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Hello, and welcome to Episode Thirty-Eight of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features part one of a two-part interview with Joseph Berger of the University of Pennsylvania. But to begin, we’d like to tell you about MSDF’s Drug-Development Pipeline.

 

Twelve drugs are currently approved in the US for the treatment of MS, but there are many more drugs in various stages of clinical and pre-clinical development. We’re keeping daily track of 44 of them in our Drug Development Pipeline.

 

To visit the pipeline just go to msdiscovery.org and click on Research Resources, and then Drug-Development Pipeline. You’ll find a finely detailed, fully referenced, and easily searchable database of all 44 of those drugs. The database includes details on each drug candidate’s physiology, its progress through pre-clinical and clinical trials, and its regulatory and commercial status.

 

Science journalist Heather McDonald has managed this database since its inception, and she updates it continuously, whenever new information becomes available. In just the last week, for example, she added one new clinical trial to the database, she updated information on two other clinical trials, and she added 5 other pieces of information. The drugs with important additions and changes were dimethyl fumarate, fingolimod, glatiramer acetate, interferon beta-1a, interferon beta-1b, mitoxantrone, natalizumab, and RPC1063.

 

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Now to the interview. Dr. Joseph P Berger is a professor of neurology and Chief of the MS Division at the University of Pennsylvania in Philadelphia. In part one of our discussion with Dr. Berger, we’re talking about the risk of progressive multifocal leukoencephalopathy (PML), a rare but serious brain infection that occasionally arises in people being treated for multiple sclerosis.

 

Interviewer – Dan Keller

The topic of quantifying risk and mitigating risk comes up with certain immunosuppressive drugs, notably natalizumab in MS but also with other drugs as well in other conditions. What are some of the confounding factors? Why is this not an easy thing to approach?

 

Interviewee – Joseph Berger

Well, it’s not easy because it’s so unpredictable. Nobody would have thought that natalizumab would have uniquely predisposed to the development of progressive multifocal leukoencephalopathy. In fact, when natalizumab was introduced, if one would have attempted to predict what would have happened, you might have said, well, we’ll see a wide variety of opportunistic infections of the central nervous system, since this is a drug that prevents the neural immunosurveillance that is necessary to prevent these diseases from occurring. However, that’s not what we see. We don’t see the opportunistic infections of the central nervous system that we see in the AIDS patient; for instance, things like cryptococcal meningitis and toxoplasma and tuberculous meningitis, it simply doesn’t happen. What we see, on the other hand, is this unique increased risk for the development of progressive multifocal leukoencephalopathy. This was an entirely, in my mind, unpredictable event. I suspect that this is true of many of the other drugs that are now coming to market; that our experience with them is limited, they have what we think is a well-defined effect on the immune system – they’re not broadly immunosuppressant – yet our knowledge of the immune system is such that we don’t understand fully the downstream effects they have. And it’s only after we’ve used these drugs for a number of years do we have a comfort level with what sort of risks that are engendered by their use.

 

MSDF

But it’s not unique to natalizumab; other drugs can induce this whether in neurologic conditions or even rheumatologic conditions. Is that right?

 

Dr. Berger

Yes. In talking about PML, that is true that there are other drugs that carry black box warnings for the development of PML; however, there’s something unique about natalizumab and another drug that is somewhat related to it and now off the market called efalizumab, which was a drug which went by the name of Raptiva and was used for the treatment of psoriasis. So there are drugs that uniquely increase the risk of PML and there are those that marginally increase the risk of PML, and one shouldn’t conflate them. And though a drug carries a black box warning for PML, it doesn’t necessarily mean that the risk is the same as it is with another drug that may also carry such a warning.

 

And let me explain this a little further. If you look at natalizumab and you look at efalizumab, those are drugs that have been used for conditions that had never previously been associated with progressive multifocal leukoencephalopathy. So despite the fact… And natalizumab, as you know, is used in the treatment of MS and used in the treatment of inflammatory bowel disorders, in particular Crohn’s disease, efalizumab used in the treatment of psoriasis; these are autoimmune diseases. And prior to the availability of these compounds, we did some aggressive immunosuppressive therapies in the treatment of these diseases. We would treat them with drugs like Cytoxan and azathioprine and high-dose steroids; a wide variety of things were employed. Yet until the PML experience with natalizumab and efalizumab, we had never seen PML in the setting of multiple sclerosis, in the setting of inflammatory bowel disease, or in the setting of psoriasis. So that tells you that there’s something unique about the drugs that we’re using and that it’s not necessarily the underlying condition that is responsible.

 

The second is when you start the drug, you do not see PML develop immediately; it takes some time. So the experience with efalizumab was three or more years, the experience with natalizumab is typically 12 months; actually the vast majority of cases – over 80% - have been on natalizumab for 24 months, so they’re on the drug for a long time. The shortest latency from initiation to the development of PML has been a single case in which it developed within eight months; everything else is 12 or more months. So what is that telling you? That tells you that the drug is doing something fundamentally to overcome the barriers to the development of this disease and that it’s not simply opening up a gate and letting the horses out; it’s doing something to the pathobiology of the disease.

 

And then lastly, the incidence with which we see PML with natalizumab – and presumably with efalizumab, although the numbers were much smaller – is extraordinarily high in the appropriate context. So for natalizumab, the risk of developing PML, provided you’re on the drug for two years, you’ve seen prior immunosuppressive therapy, and you’re JC virus antibody-positive so that you have been exposed to the virus that causes this disease, if you have all three of those, your risk is on the order of 1 in 90 or thereabouts. That is a risk that is commensurate with what we see with HIV-associated PML, so it’s very, very high.

 

However, if one looks at these other drugs which I have called Class 2 agents in several papers now; drugs like rituximab, also a monoclonal antibody though directed against CD20, drugs like brentuximab vedotin or mycophenolate mofetil – which is CellCept – those drugs, too, carry black box warnings for the development of PML; however, the setting in which PML occurs with their use is almost always with a condition that already predisposes you to the development of PML. So with rituximab, for instance, it’s seen with lymphoproliferative disorders, or with transplantation, or with autoimmune diseases in which PML had already been described long before the use of rituximab for the condition. And the same is true with these other drugs.

 

The second is there’s no latency to the development of the disease, so this is strictly a stochastic event; you may start rituximab today and in two weeks’ time develop PML. There’s no way that somebody’s developed PML in two weeks’ time. What that indicates is that individual was predisposed to developing PML, that virus was already in their brain, it was percolating there, your immune system was suppressing it adequately so it wasn’t expressing itself. And now you’ve done something, you’ve tweaked it a bit and the PML is now expressing itself because you’ve introduced the drug, but the drug fundamentally is not changing the pathobiology of the disease.

 

Lastly, although we do not have good figures on this, but the best data that I have is that we’re talking about orders of magnitude lower risk with these other drugs. So rituximab, for instance, the risk is probably on the order of 1 in 30,000, or something to that effect. That compared to 1 in 90 when you have all the risk factors that I described with natalizumab. So we’re talking orders of magnitude difference. So I’d suggest that we avoid conflating these drugs when talking about PML risks, and I think that this is something that is generalizable for other risks; I mean, PML is just one risk, but we see other infections and other things that have occurred with other drugs that we’ve employed tweaking the immune system, and I don’t think that one should necessarily put all these drugs that cause these things in the same boat.

 

MSDF

These drugs that are used in other conditions that do in themselves predispose to PML, when they’re used in MS which as a disease does not, on its own, predispose to PML, these same drugs – azathioprine, cyclophosphamide, mycophenolate – add to the risk when you give natalizumab?

 

Dr. Berger

That’s what it looks like. So when Biogen looked at the data that they had available from the initial cases of natalizumab-associated PML, one of the risks that they identified was the increased risk of the development of PML in those individuals that had previously received immunosuppressive therapy. And it really didn’t seem to matter which immunosuppressive therapy it was, it was any immunosuppressive therapy. However, it may be different with the different immunotherapies, it’s simply that the numbers weren’t large enough for one to say that this was particularly associated with azathioprine. People in Europe like to use azathioprine often very early in the course of the disease, so they were seeing a bit more PML than we had seen in the United States at least initially. And it wouldn’t surprise me if there aren’t certain immunosuppressive agents that increase the risk significantly compared to others, but we simply don’t have that data. And what is known is that it really doesn’t matter, any of them can do that.

 

MSDF

Without really having a firm understanding of the pathogenesis of PML – you know the risks but maybe not exactly why it’s occurring – how do you come up with a framework for mitigating risk; is it purely empiric?

 

Dr. Berger

That’s an excellent question. So it turns out that this was a back-of-the-textbook disease; this was the disease that occurred very, very rarely. Between 1958 and 1984 in a review published by Ben Brooks and Deward Walker, there were only 230 cases that they were able to come up with; 1958, of course, is when the disease was first described. So this was a very, very rare disease until the AIDS pandemic where people developed some interest in it, and then it really became interesting when we saw it with natalizumab. And there’s been more resources put into the study of this disease since then, so that we do have a better understanding of the pathogenesis. But in identifying these risks, we’ve worked backwards; you know, we say, alright, what does natalizumab do? So why is it that we see this increased risk?

 

So in getting back to your question, we know that immunosurveilling the brain is important; so if you have a drug that prevents appropriate immunosurveillance of the central nervosus system, it should not surprise you that the risk of PML is increased. And we do think that the alpha-4 beta-1 integrin inhibition that occurs preventing the entry of JC virus-specific cytotoxic T lymphocytes into the brain is in a large measure – but not completely – contributing to the development of PML. We also know other things. For instance, the virus that we are likely infected with – and the infection occurs very early in our lives; seroepidemiologic studies indicate that most individuals that are infected are infected before the age of 20 – that that virus is a virus that is ubiquitous but incapable of growing effectively in glial tissues; it is a virus found in urine and found in the urinary tract, it’s found in kidney and renal pelvis and bladder, and it’s found in high concentrations in some people’s urine. That virus will not grow in the brain. So something has to happen to the virus.

 

Does natalizumab change that in some way? Well, we think it does. We think it does that by causing the release of immature B cells; these immature B cells can harbor JC virus, and that virus as these B cells mature there is an upregulation of transcriptional factors that transactivate the virus, it is occurring in a milieu that may uniquely predispose to a genetic rearrangement of the virus enabling it to become a form of the virus referred to as a prototype strain or a neurotropic strain that can grow in the brain. So we think that there are at least two very large barriers that prevent PML that are affected by natalizumab; there may be others. And as we investigate this disease further, our understanding may improve and these explanations I’m telling you will likely be expanded. And, in fact, it may be that some of the thoughts that we have are wrong, because the story with the B cells is actually somewhat hypothetical; there’s some preliminary evidence supportive of it, and that’s why I tell people that I’m fond of Ralph Waldo Emerson’s comment, that consistency is the hobgoblin of small minds. If I stand before you a year from today and tell you something different, it’s only because we’ve learned more about it.

 

MSDF

So how do you mitigate risk and how do you get the point across to patients to let them make informed decisions with you?

 

Dr. Berger

So this is difficult, but we lay the facts out to them. And the facts are that there is this risk of PML, the risk in individuals that are JC virus antibody-negative are very small, the product label puts the risk at less than 1 in a thousand; the belief is that it’s significantly less than that. The fact is that we do see individuals who are JC virus antibody-negative months before the development of PML – it’s rare but it occurs – and there have been studies, including my own, that have indicated that the antibody study doesn’t necessarily mean you’ve never been infected by the virus. So one shouldn’t conflate JC virus antibody negativity with never having been infected, but it is a very good marker for the development of PML, and it is one that needs to be monitored carefully at six month intervals.

 

So we lay out to the patients that if you’re antibody-negative your risk is infinitesimal and an acceptable risk, and that we monitor you carefully. The second is this is a disease that can be life-threatening, and if not life-threatening certainly severely debilitating – multiple sclerosis I’m talking about – and there are people that have very aggressive disease and will accept the risk of developing PML, knowing that the risk may be 1 in 100, but their risk of developing something that was going to leave them wheelchair-bound and totally disabled is very, very high, and they say I’d rather take the risk of the development of PML.

 

So we do know what the numbers are. There’s a table that’s been published and gets revised periodically that puts into it JC virus antibody positivity, duration of therapy broken up into 24-month epochs, and prior immunosuppressive use. So we know what the risks are; the highest are in individuals that are treated more than 24 months with the drug, are JC virus antibody-positive, and had previously received immunosuppressive therapies.

 

MSDF

What about monitoring for signs and symptoms of PML if someone does choose to go on some of these drugs?

 

Dr. Berger

Yes, so that’s very, very important. And we do have patients that even in the face of JC virus antibody positivity, we and the patient elect to continue them on the drug. And patients on natalizumab need to be monitored very carefully for the development of PML, and that is a combination of both clinical screening – there is a TOUCH program that queries for the development of symptoms that may be concordant with PML – unfortunately, you also see symptoms of that nature develop in MS patients, as well, so it’s sometimes difficult to tell whether it’s MS or PML – and at that point in time you definitely want to survey them with an MRI. And, in fact, many of us do MRIs at regular intervals in patients on Tysabri attempting to identify the disease – PML – when it is asymptomatic. And those people seem to do best; the prognosis both in terms of disability and in terms of survival is better when you pick the disease up while they’re still asymptomatic, and they have what one would refer to as radiographically isolated PML.

 

So it’s a combination of vigilance, asking the right questions, performing your physical examination, and obtaining period MRIs, and in those that are JC virus antibody-negative – or even the antibody-positive – repeating that study periodically. And the reason I say that repeating it periodically even in the positive patients is because what’s been demonstrated is that the higher your antibody titer, the greater the risk of developing PML. So there’s a threshold now that’s been identified and individuals above that range have a significantly higher risk of developing PML than individuals who are seropositive but below that level.

 

MSDF

And just to clarify; the TOUCH program is the Tysabri Outreach Unified Commitment to Health? This is what you’re referring to in terms of monitoring for signs and symptoms of PML?

 

Dr. Berger

That is correct. That is the risk mitigation strategy that is FDA-approved and that Biogen has implemented in an effort to decrease the likelihood of PML developing.

 

MSDF

Very good, thank you.

 

Dr. Berger

My pleasure.

 

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Thank you for listening to Episode Thirty-Eight of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

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Host – Dan Keller

Hello, and welcome to Episode Thirty-Seven of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Jeanne Loring, who works with human induced pluripotent stem cells in a mouse model of MS. But to begin, we’d like to tell you about one of the most useful features of the MS Discovery Forum.

 

Each week somewhere between 30 and 110 papers related to multiple sclerosis are published in the scientific literature. At MSDF, we endeavor to list them all, publishing links to a curated set of each week’s new papers every Friday at msdiscovery.org/papers.

 

The first step in curating this list is an automated PubMed query that pulls all papers containing the terms multiple sclerosis, myelin, optic neuritis, acute disseminated encephalomyelitis, neuromyelitis optica, transverse myelitis, experimental autoimmune encephalomyelitis, cuprizone, neurodegeneration, microglia, and several related terms. This query returns many false positives. MSDF editors read all the titles and most of the abstracts and make judgments about which papers are directly relevant to MS or related disorders. Last week, for example, the query returned 139 papers and, in our judgment, only 58 of them – 42% – were truly MS-related. Some weeks the proportion is even lower than that.

 

The query terms neurodegeneration, myelin, and microglia are responsible for most of the false positives. Neurodegeneration, in particular, returns many references related to other neurodegenerative disorders, such as Alzheimer’s disease, Parkinson’s disease, amyotrophic lateral sclerosis, stroke, and hypoxia, to name a few. Editorial judgments on which articles are relevant are often subjective, and we frequently struggle with those decisions. It’s easy to decide relevance when an article actually mentions multiple sclerosis. It’s harder when it mentions only myelin or only Th17 cells. If you think we’ve missed an important MS-related article—or if you think we’ve included an irrelevant article—I hope you’ll let us know by emailing us at editor@msdiscovery.org. And we’re open to suggestions on how to adjust our PubMed query to decrease false positives and false negatives.

 

Once we’ve chosen which of the articles to include in the week’s list, we select between two and four of them as Editors’ Picks. Those are the week’s articles that seem to us to be the most important or interesting or intriguing. Once again, we invite readers to take issue with our choices. We’d love to hear about important articles that we have not designated Editors’ Picks or, on the contrary, Editors’ Picks that don’t deserve the honor.

 

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Now to the interview. Dr. Jeanne Loring is Professor of Developmental Neurobiology and Director of the Center for Regenerative Medicine at the Scripps Research Institute in San Diego. She and her collaborators have been testing human neural precursor cells derived from embryonic stem cells in a mouse model of MS. The cells are injected into the spinal cords of immunocompetent mice with a model of MS induced by a neurotropic hepatitis virus. The cells are rejected within a week, but in that time they suppress the immune system and induce remyelination.

 

Interviewer – Dan Keller

In terms of how you came upon your most recent finding about human pluripotent stem cells in the mouse model of MS, could you give me a little bit of the back story?

 

Interviewee – Jeanne Loring

Oh yeah, sure. It was really interesting. So Tom Lane and I set out to try to develop a stem cell therapy for MS using human cells. So as a control experiment, we took human pluripotent stem cells, in this case embryonic stem cells, and turned them into neural precursors; differentiated them just a little bit. And then we transplanted them into Tom’s mouse model of MS. These mice were not immunosuppressed, and so we expected the cells to be rejected. And this was just our first experiment. But the results were not what we expected. After the cells were rejected, the mice started getting better, and their clinical scores improved. And then after several months, these mice were almost indistinguishable from normal mice.

 

The first thing we thought was that we’d gotten the cages mixed up, and we were looking at something different. But we’ve repeated the experiment now more than a hundred times, and about 75% of the time we get the same result. So what this tells us is that these cells that we put into the animals are having some effect during the seven days that they exist in the animals that leads to both immunosuppression and remyelination and a clinical improvement which is quite remarkable.

 

MSDF

When you say 75% of the time, does that mean you get almost no effect 25 % of the time? Or does it mean that 75% or the mice? Because that would say whether you’re making your stem cells right or not.

 

Dr. Loring

It’s 75% of the mice.

 

MSDF

How do you explain it at this point, or where do you go from here to find a way to explain it?

 

Dr. Loring

So once we’d realized that we had a phenomenon that was repeatable, we realized that there was something special about these cells. And we tested other cell types, like the pluripotent stem cells that they were derived from, and human fibroblasts, and discovered that neither one of those was effective. And since then we’ve also tried other ways of making neural precursor cells, and those cells aren’t effective either. So it’s something extremely special about the cells that we used in these experiments, which is very lucky when you think about it.

 

So we’ve now, both Tom and I – even though we’re not in the same place – we’ve set out to try to find out what it is about these cells that gives them these properties. Our first sort of cut on this – our hypothesis – is that the cells are secreting something that has a lasting effect. Our sort of big picture idea is that there are probably more than one protein or glycoprotein being secreted. And together they suppress the immune system so they act on the inflammatory response so that they increase the number of regulatory T cells that are produced and decrease the other T cell types. And they induce remyelination.

 

So Tom is now working on trying to identify what factors these cells make that are inducing the T regulatory cells. And on my side, we’re trying to identify what it is that makes them remyelinate.

 

MSDF

When you make these cells, how do you know you got a good batch? Can you characterize them? Are there biomarkers, and you can say, “We did it right this time?”

 

Dr. Loring

Yes. In fact, that turns out to be really important because we did it wrong a few times. And we have a gene expression signature. It’s essentially diagnostic assay for this particular cell type. We’ve boiled it down to a set of qRT-PCR markers. And, because we have collaborators in Australia, we had to be able to transfer this quality control assay to them. So far it seems like those markers, I think it’s a group of 10 or 12 markers, seem to be predictive of the cells’ working in the animals.

 

MSDF

And just to clarify, that’s real time quantitative polymerase chain reaction? How are you going about characterizing what they’re doing? I mean, are you doing cytokine measurements or you’re looking at cells that get produced in the mice?

 

Dr. Loring

Tom is really handling the cells that get produced in the mouse. He’s doing the T cell analysis. What we’re doing, we developed an in vitro cell culture method to look for the effect of these cells on maturing oligodendroglia in culture. And we found that something secreted by these cells which shows up in their culture medium actually induces maturation of oligos – of OPCs – in vitro. I guess that’s another result that we didn’t expect to be quite so clear. So that shows that there’s something that is secreted by the cells. I mean, that’s the most likely idea. And on Tom’s side, he’s shown that the conditioned medium from the cells induces T-reg generation. And on our side, we’ve shown that conditioned medium from the cells induces oligo maturation.

 

So now we’re trying to figure out what it is in that conditioned medium because now we think we can do a cell-free therapy for MS if we can identify what the factors are. It would be much simpler for us to do even a protein therapy for MS than it is to do a cell therapy. So both sides are taking sort of a candidate gene approach in which we’re identifying the proteins that are most highly specifically expressed in the cells that work in the mice. We have a list of those proteins, and we’ve sort of snatched a few candidates out of that group, and we’re testing to see whether each one of those proteins in purified form has the same effect as the conditioned medium.

 

The other approach, which is more tedious but more likely to actually tell us what’s going on is for us to fractionate the medium into different sized proteins and then test each one of those fractions. We’re in the process of doing that right now.

 

MSDF

But it sounds like these cells are pluripotent. Not pluripotent in the normal sense of a stem cell leading to different lineages, but they have a couple of effects. One is the immunomodulatory, the other is regenerating oligodendrocytes. Do you think it really requires the gamish of proteins? If you fractionate them, will you possibly lose the signal? And that’s a big matrix to put back together again.

 

Dr. Loring

Yes, it is. And obviously, if we get no signal from our fractions, we’ll put our fractions back together again and try to find out whether – there are only three fractions, really, right now. So we’ll try different combinations of these fractions to try to find out if we can reproduce the effect. The effect is quite robust. We essentially get no maturation in medium conditioned by other cell types, but we get very strong maturation when we use conditioned medium from this particular neural precursor cell.

 

MSDF

If you only have three fractions now, is it because you just have chosen not to fractionate it even more until you know what’s going on?

 

Dr. Loring

Yes, we’re trying to hone in on it. So we don’t want too many different things to look at right away. I’m hoping that we find that only one of those fractions works, and that we can discover everything is within that fraction, but I really can’t predict what’s going to happen.

 

MSDF

It sounds like the approach would be to put everything in except one each time as opposed to keep adding back. You’ve got to find the one critical one missing that makes the thing not work.

 

Dr. Loring

Yes, and eventually we will do that with specific antibodies, but right now that is, since we don’t really have our candidates narrowed down enough, that isn’t a viable approach. But you’re absolutely right. We want to find out if that’s missing, whatever the things that are that are missing. And I’m hoping it’s not so complex that it’s five or six or seven proteins, because that’ll make it much harder for us.

 

MSDF

How do characterize the condition of the mice?

 

Dr. Loring

So that’s Tom’s area of expertise. It’s essentially an observation of the mice over time. We have a movie which I can show you, but I can’t actually do it in a recording. It’s quite obvious when the mice – they’re blind scored so the person who looks at the mice and sees how well they’re walking around doesn’t know whether they’re controls or experimentals. If you just see the movies that are selected at particular times after the cells have been transplanted, it’s quite dramatic. They have a much better clinical score. Essentially, they’re almost normal after six months.

 

MSDF

And how are you sure that the cells you injected into the spinal cord are gone, that they’ve been rejected completely?

 

Dr. Loring

That’s a good question. We used a method for live imaging of cells in which we use luciferase to label the cells. And then we used an instrument which allows us to image the cells in mice – in living mice – over time. So we did this in individual mice and saw that they disappeared over time. And after eight days we couldn’t detect them anymore. That doesn’t mean there isn’t one or two left because the resolution isn’t that high. We will go back eventually and look through sections of the spinal cords and see whether we can detect any. The other thing we can do is (skip 13:37) a human-specific markers. So we can just take a section of the spinal cord and find out if there’s any human cells in it at all, or any human genes in it at all. But we haven’t done that yet.

 

MSDF

Do the cells have to be gone? Have you tried injecting a second time?

 

Dr. Loring

No, we haven’t. We don’t know. We really don’t know. It would be very interesting if it reversed the effects. Then we’d really have a problem to solve.

 

MSDF

What else is there important to add or that we’ve missed that’s important to this kind of research?

 

Dr. Loring

So our dream is that we will identify a group of proteins and the concentration of those proteins necessary to have these two effects in this mouse model. And then we will do some biological engineering. We’ll be putting the cells into these little spheres and matrix that allows slow release of these proteins or controlled release of these proteins. And then, instead of putting cells in, we’ll put these beads in. And I don’t know whether that would end up being the final product or not, but there are lots of ways to deliver proteins, and this one I find rather attractive because it doesn’t require pumps or syringes. And I think that’s certainly the direction we’re going to try to go in. And so Tom Lane and I have just gotten an NIH grant for five years of funding, which seems like a very long time to me. So in five years we will have discovered the best way to deliver these things. We’ll discover what they are and the best way to deliver them. Tom has put conditioned medium into the mice, and it also works.

 

MSDF

Because I was going to ask, had you encapsulated the cells just to see that the supernatant does it without cell contact?

 

Dr. Loring

It turns out that the conditioned medium itself, you inject that into spinal cord, it’s not as dramatic an effect, but you have a clear clinical improvement.

 

MSDF

Have you tried injecting it either IV or intraperitoneally?

 

Dr. Loring

Yes. Well, we didn’t inject the conditioned medium. We did try injecting the cells, and they pretty much stayed where we injected them. These cells, unlike mesenchymal stem cells, they aren’t very migratory. So they don’t really have the receptors that cause them to move to areas of inflammation like CXCR4, for example; they don’t express that on their surfaces. So that does not seem to be a good delivery method for these cells. They don’t go anywhere.

 

MSDF

I was also thinking that if something they secrete is important, whether it circulates. Maybe they’re not making enough concentration if you inject them outside of the central nervous system, but it seems like you’re going to be faced with a little cumbersome problem in a clinical situation years and years ahead from now if you have to keep injecting proteins into the spinal cord as opposed to more peripheral.

 

Dr. Loring

I agree. And the solution to that is generally to look for peripheral effects and then try to suppress those when you do a therapy like this. That’s a long time, and we could certainly imagine how we would do it. But we need to know what those proteins are before we can decide on whether we expect them to have effects peripherally or not. But I agree with you; delivering them intravenously would be far easier.

 

MSDF

I know you have a lot of work ahead of you now with this, but is there another animal model of MS – or even another mouse model of MS – where you can see if it works even in a mouse model different from this one?

 

Dr. Loring

Yes, we’re actively pursuing that with our collaborators in Australia. And it’s interesting because they’ve gotten some positive preliminary results using the EAE model, but the approach to the EAE model I’ve realized is quite different. Generally, what people do is they provide the therapy at the time that the pathology is developing, and they try to prevent it, which is a really different idea than what we had using the mice that are already paralyzed. So they have found that if you can deliver the cells at least close to the spinal cord, then you can see some effects. The problem is that in Australia, and this is one of those technical things we had not anticipated, they don’t have permission to inject cells into the spinal cord. So they have to go through their animal rights people or their animal protection groups and try to get permission to do so. So with Craig Walsh at UC Irvine we have started doing parallel experiments with the EAE model. I’m not necessarily sure that it’s going to have similar effects. I mean, I really don’t know.

 

MSDF

Can you describe how these mice in your experiments were made to have MS?

 

Dr. Loring

Yes, they were given a virus, a neurotropic virus, which kills off the oligodendroglia. They become demyelinated, and there is a secondary inflammatory response. So the mice are actually paralyzed in their hind quarters at least by the time we put the cells in. They have to be fed by hand. So this is not a trivial thing to do. But we’re trying to reproduce the effects during the progressive form of MS, for example, or during an attack of MS. So we’re trying to repair the mice or cure the mice that are in a condition which would be similar to the worst case scenario for people with MS.

 

MSDF

Do you think this may also have effects not only on the myelin, but also on damaged neurons?

 

Dr. Loring

We don’t know, because the mice haven’t really had enough time to get a lot of neuronal damage, but that’s a very good question. We don’t know yet.

 

MSDF

I appreciate it. Thank you.

 

Dr. Loring

You’re welcome. It was a pleasure.

 

[transition music]

 

Thank you for listening to Episode Thirty-Seven of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

[outro music]

[intro music]

 

Dan Keller: Hello, and welcome to Episode Thirty-six of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an extended interview with Jenny Ting, an immunologist who studies the inflammasome, a multi-protein oligomer that’s part of the innate immune system. But to begin, we’d like to tell you something about why we started the MS Discovery Forum.

 

MSDF, located at www.msdiscovery.org, is an online portal providing news and information about research in MS. We offer a unique combination of news and background articles written by professional science journalists, viewpoints from thought leaders and subject matter experts, and technical resources that enable sharing and analysis of information and open discussion among MS stakeholders in academia, industry, and the clinic. Membership in MSDF is free, and all content on the site is provided on an open-access basis to the entire MS community.

 

MSDF stands apart for its comprehensive and independent coverage of MS research. Readers can depend on MSDF to report and verify, not merely re-run press releases. MSDF’s overarching goal is to accelerate progress toward clinically useful advances.

 

We launched MSDF in April 2012 with the aim of filling a knowledge gap in MS research. The plan was to promote collaboration among scientists who are separated by specialized skill sets, institutional boundaries, and geography. It’s well known that these individuals attend different meetings and read different journals. And while it’s common knowledge that scientific breakthroughs and medical advances most typically result from cross fertilization of ideas, in today’s world scientists still do not easily share ideas and collaborate on solutions. We wanted to change that, and to bring thoughts, knowledge and ideas out from the lab into the open to enlighten and inform all stakeholders in the effort to cure MS, including health care providers and people affected by MS.

 

To that end, we employ the highest standards for independent journalistic reporting, including the use of multiple viewpoints to give a full picture of a finding’s impact. We aim to make scientific findings accessible to everyone, from busy clinicians to cutting-edge researchers to people with MS and their loved ones. We avoid short-cuts, such as the use of jargon, that get in the way of comprehensibility. We highlight the potential clinical impact of the research we cover, even when we’re covering basic research that may be years from direct clinical relevance. And we seek innovative ways to communicate important information to our audience.

 

[transition music]

 

Now to the interview. Dr. Jenny Ting is Professor of Microbiology in the Institute for Global Health & Infectious Diseases at the University of North Carolina at Chapel Hill School of Medicine. In addition to MS, Dr. Ting’s research interests include the role of the immune system in infection, inflammation, and cancer. Science Journalist Carol Morton caught up with Dr. Ting at a recent Keystone meeting.

 

Carol Morton: I appreciate your taking time out to talk to MS Discovery Forum. So we’re at the Keystone meeting on Neuroinflammation in Taos, New Mexico, and you gave a very interesting talk today.

 

Jenny Ting: Thank you.

 

Morton: So can you tell us what you’re talking about when you’re talking about the inflammasome and the particular proteins that you’ve been looking at.

 

Ting: The groups of proteins that we work on are cytokines, and cytokines are made by immune cells. And they have a tremendous impact on inflammatory responses. As you know, in MS there is a big immune component, so these cytokines will influence it. And in most cases cytokines activate the immune system. One of the key cytokines that we’ve studied is called IL-1, interleukin-1 beta; this is the one, for example, that causes fever, inflammation, and so forth. So it’s called interleukin-1 because it was the first one discovered, and it turns out it’s probably one of the most important ones.

 

So because it’s a master cytokine, and once it goes it kicks off all the other cytokines, so there’s a cascade that goes on. So it could activate other cells to make other cytokines, so it’s like a vicious cycle. Obviously, this becomes a pretty important target to think about. The process that causes this cytokine to be produced is a very big molecule that’s comprised of different proteins. And these different proteins, they are, together, called the inflammasome for inflammation large complex because “some” means large complex. Inflam- is inflammation, as in inflammasome. It’s the name given by Jürg Tschopp.

 

And so this process where you have this big complex, and as a result you get the cytokine called interleukin-1 beta, what happens is that interleukin-1 beta has now been implicated in so many diseases including arthritis, very rare diseases that causes a lot of inflammatory responses. It’s involved in skin allergies. It’s involved in colitis, you name it, and it’s involved in smoke-induced chronic obstructive pulmonary disease, COPD, that we see advertised on TV. So all of these have this component of this molecule.

 

Morton: So anything that releases IL-1 beta, inside the cell there’s a cluster of proteins that have to come together to make it.

 

Ting: Right.

 

Morton: And then it gets secreted and does its job.

 

Ting: Yes. And as we learned today, and actually it’s been published, but may be new to some of the audience, is that this whole complex can also be excreted in some ways into the cell, you know, pushed outside of cells so it can go from perhaps one cell to the other. So we have previously found that this can be a complex that’s membrane bound, and that’s called an exosome. So it’s both just like a minicell that goes from one cell to the next and make the next cell inflammatory as well. The speaker today showed that, in addition to that, it can also go out as a complex, perhaps naked. It seems like they are not really membrane bound, so that’s a different form. So it could be different forms that goes out from one cell to the next causing inflammasomal activation in the next cell and therefore perpetuates this IL-1 process.

 

Obviously, in normal hosts there must be a way to turn off this process, otherwise we would be, you know, a little ball of pus sitting on a chair. So obviously these don’t go on forever. The problem with chronic inflammatory diseases is many of these things, they don’t go on probably all the time, but they do increase. So what we did is really look at mice lacking genes that can make these proteins. This complex is usually comprised of at least three components; you knock out one and you can’t make IL-1 anymore. Actually, I should say five components. So we did that, and what we found was that if you take this out, the models of MS suggests the well-known mouse model, EAE, and another model that we’ve been really pushing, although it was initially worked on in the late 1960s and early 70s, this model of neurotoxicant-induced demyelination. In both of those models this process of inflammasome/IL-1 turned out to be bad.

 

So if you remove this process, the disease is much more attenuated. So that’s one of the really interesting parts about what we had found is that potentially this could be a target. And the good thing is that there is certainly some companies that have successfully made anti-IL-1s. So there is an IL-1 receptor antagonist that inhibits this process. There is an antibody against IL-1 that will inhibit this process. So certainly there are therapies, if this is true, that this is part of the MS problem that this could be used as a therapy.

 

The other thing we have found, which I didn’t get a chance to talk about, is that we did look at the remyelination phase and found out that, for example, IL-18 is not very good for remyelination. Of course, remyelination is what everybody would like to have, is a reparative process. And so one possibility is, can we block the IL-18 pathway, and can we get better remyelination processes. So those are some of the thoughts that we have.

 

Morton: So have you examined a number of the ILs from 1 to 18 or…?

 

Ting: No, because 18 is the product. So this inflammasome actually has many different targets. One of them is IL-1 beta; that’s the key one. Another one is IL-18. So we went from there to look at what’s downstream of the inflammasome and found out that IL-18 actually has a role both in making MS disease models worse and in reducing the extent of remyelination. So it doesn’t look like it’s a great protein to have around. So the question is can we try to inhibit this molecule.

 

Morton: Just to make sure that I’m clear on that: the inflammasome is a cluster of proteins that come together in an immune cell, like a T-cell, or a…

 

Ting: Usually it’s a macrophage or a microglia or an astroglia.

 

Morton: A macrophage or a microglia. And then that makes the IL…

 

Ting: So what you have is – I don’t know if the audience might be familiar with the coagulation pathway where you have one protein that has to be cleaved into a smaller protein. Then this protein B goes and cleaves a second protein from a bigger form to a smaller form. And the smaller form, in every case, is the mature protein that has activity. The bigger protein is the inactive form that doesn’t do anything. So this exactly the same. Pro-IL-1 has to be cleaved into IL-1. Pro-IL-18 has to be cleaved into IL-18. And what that cleavage process is this inflammasome complex producing an enzyme that will cleave these proteins.

 

Morton: So the inflammasome is like Edward Scissorhands running around cutting proteins making them active.

 

Ting: Yes, that’s a great analysis. So it’s just exactly like that. The inflammasome produces this – like you said – Edward Scissorhand that then this guy can go and prune the roses and prune the bushes, and they’re different, and they have different functions.

 

Morton: And it’s the starting block for the activity of the IL-1 and IL-18.

 

Ting: Right, so the bushes are like – if the roses are the IL-1, you can decorate it; you can give it to somebody; you can make it into a bouquet. So that’s the kind of idea. And then if you have a bush, you know, you can potentially do other things with it. Or if he’s cutting some edible plants you can use that for cooking. So that’s the whole idea. Whatever you produce has different effects. And it turns out IL-18, in our hands, looked like it’s not a good molecule. We have previously found that a cytokine called TNF, which has different roles depending on what it binds. So if it binds to TNF receptor 1, then it’s not so good. If it binds to TNF receptor 2, it actually enhances remyelination, so again, something you want.

 

And there’s recent talks and there are small molecules where people tried to activate the TNF receptor 2 pathway, and they found that that really enhances the remyelination process. It’s kind of really neat; if you can dissect these pathways well enough, then you might be able to use drugs to target MS.

 

Morton: So what are the next questions that you’re asking? Where are you going from here?

 

Ting: So we have a number of directions. Certainly, like I say, I raised the concept of IL-18; so can we target that molecule? In our own lab we’re also looking at several other pathways. So we have found a pathway that’s really important for cell-cell interaction that’s important for MS activation. And the molecules are called plexins and semaphorins. And this is a pair of proteins that seems to activate the immune system especially during MS. So we’ve done that in disease models, and we actually produce a blocker of that pathway. And we have treated mice, and they look much better. We showed that when they’re going through relapse, we can actually prevent them from coming back with a relapse.

 

So, very similar to some other MS drugs that are on the market, we’d like to think about this as additional possibilities. So those are some of the things that we’re doing.

 

Morton: What cells are these on?

 

Ting: These are T-cells and dendritic cells so they’re…

 

Morton: They’re talking to each other.

 

Ting: Yes, exactly, they’re talking to each other. And in an MS situation they talk to each other, they activate T-cells, which destroys the myelin. So if you can block that interaction, many of the drugs that are used for MS actually are targeting exactly that interaction pathway. For example, Tysabri is one that’s not so much dendritic cells and T-cells, but it reduces T-cell migration through the vasculature into the blood brain barrier. So that’s one of them where they block T-cell activation. So we are trying to block T-cell activation as well, but at the face of these two cell types.

 

Morton: If the inflammasomes, if they were superheroes or characters in an Oscar-winning movie, what would their personalities be, do you think?

 

Ting: I think they would be very powerful because they impact a lot of disease processes, yet they have very strong roles so that, when they’re used properly, they can defend against all sorts of stuff. Whey they’re used improperly, they can really cause a lot harm. So if they’re a superhero, people always say Batman has a dark side, right, a really dark side and a really good side. Maybe that’s what they are.

 

Morton: That’s a good analogy.

 

Ting: They’re not like Superman because Superman seems like all good.

 

[transition music]

 

Keller: Thank you for listening to Episode Thirty-Six of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

[outro music]

[intro music]

 

Hello, and welcome to Episode Thirty-Five of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Daniel Reich, an expert in MS neuroradiology. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Every week somewhere between 30 and 100 scientific papers related to MS are published in the peer-reviewed literature. And every Friday MSDF lists them all. You can find this week’s list, as well as three years’ worth of past lists by clicking on the Papers tab at the top of every MSDF page. In addition to listing the new papers, we also have a section containing classic papers in the field, along with commentary about what makes them classic. We’d love it if you’d like to suggest a classic paper we haven’t yet listed, and we’d love it even more if you’d like to contribute commentary. Please send your suggestions to editor at msdiscovery.org.

 

In addition to detailed original reports on new research, MSDF also curates MS-related news from around the Internet in a series of news briefs we call Research Roundups. In our latest Research Roundup, we reported on a second case of progressive multifocal leukoencephalopathy in a patient taking fingolimod. We mentioned a new trial of mesenchymal stem cells that will soon begin recruiting people in Canada with relapsing or progressive MS. And we pointed out that while scientific research was a favorite choice of America’s 50 biggest philanthropists last year, no neurological disease benefitted directly from the $1.6 billion they contributed. If you happen to have one of those folks on speed dial, we hope you’ll put in a good word for MS research. You can find our Research Roundups by clicking on News and Future Directions and then on News Briefs.

 

If you enjoy this podcast and find MSDF helpful, please consider supporting us with a donation, even if you’re not a billionaire. MSDF is run by a small team of reporters and editors. We are devoted to bridging the gaps between scientific disciplines to speed the flow of information from the lab bench to the bedside. Our ultimate goal is to facilitate the discovery of a cure. We believe one of the best ways to do that is to bring independent, research-focused news to a professional audience on a platform that fosters discussions and discourse. Help keep us going by visiting our website and clicking on the green “Support MSDF” button next to the “Research Resources” tab on the top right of our screen.

 

[transition music]

 

Now to the interview. Dr. Daniel Reich directs the Translational Neuroradiology Unit in the National Institute of Neurological Disorders and Stroke, part of NIH. In his practice as a neuroradiologist, he cares for patients with multiple sclerosis and other neurological diseases, and he also leads several clinical studies. Research in Dr. Reich’s lab focuses on the use of advanced MRI techniques to understand the sources of disability in multiple sclerosis and on ways of adapting those techniques for use in research trials and patient care. Dr. Reich is also a member of MSDF’s scientific advisory board. Science Journalist Carol Morton caught up with Dr. Reich at the recent Keystone meeting on Neuroinflammation in Diseases of the Central Nervous System in Taos, New Mexico.

 

Interviewer – Carol Morton

Can you tell us the value of MRI in multiple sclerosis?

 

Interviewee – Daniel Reich

The way I see it, MRI has tremendous value in multiple sclerosis in three major ways. One is in the clinic, one is in clinical trials, and the third is really for understanding the biology of the disease; it’s an incredibly powerful tool for that. And in my own evolution as a clinician and researcher in multiple sclerosis, I’ve really moved my thinking a lot from kind of using MRI diagnostically or thinking about how we might develop markers of the disease to look at in clinical trials to really the third part, which is trying to understand the disease using the MRI, or sometimes as I call it, the MRIcroscope.

 

Because really it is, in a way, a scientific tool to look at aspects of the disease that we can’t access either because we can’t study the brain tissue or the spinal cord tissue directly, and because it’s really much more sensitive than doing clinical evaluations in neurology. So one of the interesting things that came out from early MRI studies in the 1990s, many of them done at the NIH long before I got there where they started doing MRIs every month on people even before the era of disease-modifying therapy, was that new plaques that appeared in the brain occurred roughly ten times more frequently than new symptoms appeared in the form of relapses.

 

MSDF

Ten times?

 

Dr. Reich

Ten times, or maybe even more. But that was with the sensitivity of the techniques that were available then, that was the number that was found. What that’s telling you, of course, is that there’s a lot of subclinical disease activity that’s going on that we can completely miss if we are just doing examinations or asking patients to report their symptoms.

 

MSDF

Have there been eras of MRI use in MS and where are we now with it? And that could be in clinical trials and biology.

 

Dr. Reich

We’ve made a lot of progress, I think, in all three areas. The MRI is absolutely the most important paraclinical tool for making the diagnosis of MS. And since the newest generation of diagnostic criteria were established, the McDonald Criteria, MRI has really formed the centerpiece of those. So in somebody who is having symptoms that may be due to multiple sclerosis, the MRI is absolutely the most important test that can be done. And, in fact, it’s now evolved to the point where the diagnosis can be made based on a single MRI at one time in many cases in somebody who comes in with the appropriate clinical symptoms.

 

MSDF

A new challenge confronts the whole MS community in developing therapies and monitoring outcomes of interventions for progressive MS.

 

Dr. Reich

Yes. So how might MRI play a role in assessing therapies for progressive MS? That is a huge challenge. It’s a challenge I would say the majority of my colleagues in the imaging field in MS are working on; what can you measure with MRI that might be the equivalent of new plaque development for the progressive MS question? And it’s, in my view, quite unresolved. The most studied markers that have behind them the weight of evidence to date is brain volume changes – how much brain is there – which can be assessed with MRI and is being done routinely in clinical trials now. I think how exactly that’s being done, which parts of the brain to look at – grey matter, white matter, specific portions of the brain like the thalamus – remains an open question.

 

What quantitative analysis tools should you use to make the measurements from the images? How you set up the scanner? All of this is still being worked out. That idea of measuring brain volume and seeing whether therapies may slow the rate of brain volume loss appears to be relatively promising. But even with that, proof of concept early trials to see whether a therapy might work are still much larger and much longer than the proof of concept trials that work for assessing new therapies to reduce the number of plaques.

 

MSDF

By how much longer?

 

Dr. Reich

They usually are two years or so at the minimum and they would involve on the order of 100 to 150 patients. Contrast that to four to six months with 10 to 15 patients and you can see how many more therapies can be tested with the shorter, smaller approach. So, in fact, in our lab, one of the things we’ve been thinking about a lot is how we may shorten that. And in the context of progressive multiple sclerosis, I think that’s not clear how to do. However, a lot of the biological processes that are occurring in progressive multiple sclerosis, there’s now a lot of evidence that they also occur very early in the disease, perhaps even before somebody has their first symptoms. So these brain atrophy processes, I think that’s been quite well established.

 

But you can also ask the question of whether brain tissue repair. Parts of the brain that have been demyelinated that requires remyelination that occurs early in the disease and it may be relevant for progressive phases of the disease as well, or for people who have primary progressive MS. And so we’ve been thinking a lot about how to look at these early plaques that develop early in the disease and use imaging of those plaques to see how they repair in order to test new therapies coming down the block that may promote remyelination or protect brain tissue that’s undergoing inflammation and demyelination from more extensive destruction. And we think, based on the some of the work we’ve done that is going to be published next week, that we can design trials that are, again, very short – six months or so with 10 to 20 patients, 15 to 20 patients – that may be able to assess that. And, of course, we’ll need to understand whether success in such a trial would predict whether that therapy would work in larger trials of progressive MS.

 

MSDF

Are there other challenges with MRI and related to multiple sclerosis?

 

Dr. Reich

Sure. From the point of view of doing clinical trials that are generalizable to large groups of patients that are able to be implemented at multiple sites, we need to understand how to standardize our techniques better. I’ve been involved with an effort recently to develop a group of cooperating investigators in North America similar to our older, more venerable brothers and sisters in Europe who have been working together on imaging for 20 years or so in the MAGNIMS Consortium. Our group which is called the North American Imaging in Multiple Sclerosis Cooperative – or NAIMS – is really very interested in trying to understand how we can standardize high-end approaches that may be very effective for testing new therapies that may be useful for assessing tissue or repair. With this consortium, the NAIMS Consortium, we’ve been very interested in developing standardized protocols that could be useful for assessing in a multicenter way, whether new therapies that are designed to repair or protect brain tissue and spinal cord tissue work. So we’ve been working very hard to do that, and we hope that once a study can be done in multiple sites, it can often be done much more efficiently.

 

From a diagnostic point of view, the types of MRIs that are done at all different centers may be equally good for just assessing, for example, whether plaques are present in the brain of somebody who is being worked-up for multiple sclerosis. But if you have to take the next step to quantify that and to submit those results to statistical analysis, then you really need a lot more homogeneity. It’s not actually clear how much homogeneity you need, how much narratization you need, that’s an open question. Does it need to be exactly the same, or does it need to be approximately the same, or really do we need to understand the differences between what is done at one site versus what is done at the other?

 

The last area in which I think MRI is incredibly valuable and offers something that no other technique really can is the ability to study the spatiotemporal dynamics of the disease. MS is, of course, a disease that affects people young and that they carry with them for their entire life, so it can last 40, 50, 60, 70 years in some cases. And I think we all know that the disease changes a lot during that period, and it changes as people are changing and as they age, and you can’t take pieces of the brain or spinal cord and study it under the microscope. I mentioned already that clinical evaluation is less sensitive than the MRI for picking up these changes, so only with the MRI can you understand how things change and where they’re changing in the brain.

 

In that context, I think people have been going along one of two pathways for how to use MRI to understand the biology of the disease. On the one hand, people have been using the physics of MRI to build really complicated models of how different types of tissue changes – demyelination, inflammation, atrophy – could affect the pictures we take, and that’s been a very interesting but quite complicated effort and the results have been a little bit hard to interpret. The other approach is to take advantage of the rapidly evolving technical changes in MRI acquisitions to really just learn how to take higher and higher resolution pictures.

 

And I think that’s the bias that we have in our group, that’s the approach we’re taking where we think that as we begin to hone in on really fine features of structures of the brain, whether it be the cerebral cortex or the spinal cord or the brain stem or the cerebellum, we’ll begin to see things that will help to bridge this divide between what people can do in the lab with really fancy molecular techniques with what they can do in the clinical with MRI. And so that’s really where we’ve been spending a lot of our effort using very powerful MRI machines – 7 Tesla – using very advanced antennas – we call them coils – in MRI to really get high-sensitivity images.

 

Changing the way we tune the magnet to focus on things that we think are interesting. For example, one of the areas we’ve been studying quite intensively recently is inflammation in the meninges in the coverings of the brain, which we think from the pathological data are quite relevant to the disease. We have a way now that we’ve described of assessing at least some of that inflammation in MS, and we’ve been following up on that. So I think the potential of MRI as a biological tool, even after 30 years of work on it, is really largely untapped.

 

MSDF

Are there things that the MRI can’t do right now that you really want it to do?

 

Dr. Reich

Oh, absolutely. You know, MRI is based on the physics of how protons behave in a strong magnetic field and when those protons which are largely in water are aligned when they go into a magnetic field. And we can perturb that alignment, and then it relaxes back into the equilibrium state. And the rates at which that happen depend on where these protons are located, and that’s what allows us to see the tissue. And I go into that because it just illustrates that we’re not looking at T cells and B cells and microglia and axons and oligodendrocytes, we’re looking at the physics of protons in a magnetic field.

 

I would, of course, love to have a technique that combines the exquisite submillimeter spatial resolution of MRI with specificity for these various cell types or biological processes that are going on. And a lot of people have been working on this, but to date that doesn’t really exist. And part of the reason for that is because the biological processes don’t occur in isolation. Lots of different things happen with inflammation – water moves around – and so it may actually not be possible to do that, but people are still working in that. So that’s a great challenge is to figure out how we could specifically assess inflammation, myelination, axonal health with imaging. But I don’t think that precludes us, again, from using the imaging either to help with the diagnosis, to assess new therapies, or to really observe and build stories about how the biology is working in the disease.

 

MSDF

What’s happening in the cutting-edge of MS neuroradiology?

 

Dr. Reich

I think the most exciting development in MRI and multiple sclerosis is the ability to look with greater and greater precision at what’s going on in the brain and spinal cord, and how that changes over time. And that is being made possible by really rapid advances in the technology. I think that will no doubt translate into the ability to better assess the course of an individual person’s disease, whether they’re responding to therapies, either immunomodulatory therapies that current exist or the reparative or protective therapies that will hopefully come online soon. And I think that’s tremendously exciting.

 

MSDF

Do you also collaborate with people in other specialty areas in the course of your work?

 

Dr. Reich

Yeah. Personally, I have many collaborations. I have collaborations with pathologists, I have collaborations with immunologists, with clinicians, with virologists, with other imagers. So for my work which really depends on understanding the intersection between the imaging we do and the biology of the disease, those collaborations are critical. Through our NAIMS Cooperative, the imaging group in North America that we’ve recently started, we’re hoping really to develop very powerful interactions among groups that have a lot of expertise in how to do imaging in multiple sclerosis.

 

So in addition to the standardization work, we’re very much hoping to be able to share techniques that we develop. And we’ve established a platform in which that is happening. We’re also hoping to use this cooperative group to sort of cross-pollinate the various labs to use it as a training forum so that the next generation of people interested in imaging and MS will, number one, get to know each other, but also learn from labs in which they don’t spend all their time. So it has a multipartite mission which hopefully will really drive the field forward.

 

MSDF

Well, thank you for sharing your thoughts on MRI and MS with MSDF.

 

Dr. Reich

It’s my pleasure.

 

[transition music]

 

Thank you for listening to Episode Thirty-Five of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

 [intro music]

 

Hello, and welcome to Episode Thirty-Four of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features a follow-up interview from last week’s episode with Dr. Pierre-Antoine Gourraud. This week, we interview Dr. Jill Hollenbach about killer immunoglobulin-like receptors – or KIR – and their relationship with human leukocyte antigen and MS. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Take some time to check out our most recent data visualization on our website. Under the research resources tab, you can find a series of interactive data visualizations useful for MS researchers. Our most recent one organizes 142 ongoing clinical trials into an interactive bubble chart. We have another visualization on the natural history of MS symptoms. The interactive bar chart allows you to see the change of various symptom severity in MS over a 30-year period.

 

If you enjoy this podcast and find MSDF helpful, please consider supporting us with a donation. MSDF is run by a small team of full-time employees and a few regular contributors. We are devoted to bridging the gaps between scientific disciplines to speed the flow of information from the lab bench to the bedside. Our ultimate goal is to facilitate the discovery of a cure. We believe one of the best ways to do that is to bring independent, research-focused news to a professional audience on a platform that fosters discussion and discourse. Help keep us going by visiting our website and clicking on the green “Support MSDF” button next to the “Research Resources” tab on the top right of our screen.

 

[transition music]

 

Now to the interview. Dr. Jill Hollenbach is an assistant professor in the department of neurology at the University of California, San Francisco. She met with science journalist Cynthia McKelvey, to talk about KIR in MS.

 

Interviewer – Cynthia McKelvey

Why don’t we start by introducing what KIR is, how it’s different from the potassium channel and what its relationship is to HLA.

 

Interviewee – Jill Hollenbach

Well, KIR is an acronym, it stands for killer immunoglobulin-like receptor. These are receptors on the surface on the surface of natural killer cells. They use generally, not in every case, but use HLA as their ligand and they have either an activating or inhibitory effect on natural killer cells.

 

MSDF

You mentioned in your talk earlier today at UCSF that they are difficult to study. Why is that?

 

Dr. Hollenbach

Just in terms of their genetic architecture. KIR occupy a complex on chromosome 19, it’s a multigene complex. And so on any individual haplotype that’s one chromosome, an individual can have between 4 and 14 KIR genes. These genes are really recently evolved, and so they’ve kind of arisen in humans as a result of repeated events of recombination and gene duplication. So what that means is that one KIR gene often at the nucleotide level looks an awful lot like another KIR gene. And so we’ve had a lot of issues. A lot of the methodologies that are available right now in terms of sequencing, part of this has to do with a lack of human genome reference alignments, but there has been a lot of difficulty in examining these genes because they look so much like one another.

 

MSDF

How does that relate to why they haven’t really seen them on genome-wide association studies?

 

Dr. Hollenbach

There’s a couple of reasons why we don’t see them on genome-wide association studies. One is that, as I mentioned, there haven’t been a lot of good reference alignments, so as a result we don’t actually see a lot of SNP markers on most of the common platforms that are used for genome-wide association studies. And then the markers that are there are often lost to quality control, because we have a lot of gene content variation, which is kind of like a copy number variant. And so if we only see a result for one chromosome, for example, for a given SNP, that is not going to pass general quality control thresholds. And, of course, you have to recognize that when you’re doing these GWAS studies, you’re looking at a hundred thousand, five hundred thousand, a million markers, two and a half million markers, so you’re not going one-by-one and saying, well this KIR-1, we expect to only see one copy or that sort of thing. So it just gets thrown out in the mix with things that don’t pass QC.

 

MSDF

How does KIR relate to multiple sclerosis specifically?

 

Dr. Hollenbach

Well, we’re trying to figure that out. So there’s been a small number of studies examining KIR in multiple sclerosis, and what seems clear is that variation in the KIR does play a role in susceptibility to multiple sclerosis. It may play a role in progression; we’re just not sure. There’s not been enough work done to say definitely what’s going on, but there’s enough evidence to say that something is going on. And some of the work that I talked about in my talk today, an analysis of KIR variation along with HLA in an African-American MS cohort, a very large study population, it seems clear that there is some association of KIR variation with susceptibility or protection for multiple sclerosis.

 

MSDF

Why study the African-American cohort? What does that tell us about MS in general?

 

Dr. Hollenbach

We want to study them because they’re different from one another; so an African-American population is going to look very different genetically with respect to KIR and HLA from a European-American population. So we want to know two things. We want to know is there something different going on with these genes with respect to disease in these different populations, OR at the same time we want to know is something the same going on? And so we can learn something both from these commonalities and differences, and both can be really important in genetics. So if there’s something that is important that’s specific in the African-American population, we want to know that, and we can only find out by looking at a number of different ethnic groups.

 

MSDF

Let’s talk a little bit more about interaction between KIR and the HLA ligand, and how that plays in with Bw4. And if we can define all of those things, too, that would be great.

 

Dr. Hollenbach

Okay. Well, so KIR molecules, as I mentioned before, need to see something, they need to have a ligand on their target cell. We have both inhibitory receptors and activating receptors. The job of the NK cell is to perform immune surveillance. So NK cells kind of wander around the body, and what they’re looking for are cells that don’t look healthy. So what does that look like and what is an unhealthy cell? It’s a cell that is virally infected, it’s a tumor cell. Those are the two main things that NK cells are looking for. And it’s a really important function because they’re part of what we refer to as the innate immune system; it’s the first line of defense against these kind of unhealthy events.

 

And so what does an unhealthy cell look like? Well, one of the things that happens in both viral infection and tumors is downregulation of MHC class I. That’s what the KIR are looking for. So when an NK cell encounters a healthy cell, it will see HLA class I, it immediately recognizes this is self, this is healthy cell at least in terms of what I’m able to see as an NK cell, and it will move on and it won’t cause any damage to the cell after making contact between the KIR and that ligand.

 

On the other hand, if the KIR doesn’t see this HLA ligand, the inhibitory KIR, an activating KIR – and we’re still not completely sure what the activating KIR ligands are – but the activating KIR is also bound to something on the surface of this cell. If the activating KIR is bound but the inhibitory KIR is not, what happens is the NK cell is going to lyse that cell which is presumably unhealthy in some ways – tumor or viral infected.

 

Now HLA class I – actually all HLA molecules – have another primary really important role which is antigen presentation to T cells. Class I molecules present antigen to the CD8-positive T cells, and so that’s how these T cells perform their role in terms of the active immune response. KIRs see a different part of the HLA molecule than the T cell receptors, and so they see kind of this piece of the HLA class I molecule that’s kind of on the side of where the T cell receptors sit. And the variation that they see on that HLA class I molecule can kind of be defined by these broad categories based on the particular amino acid residues. And it’s generally just from two to four amino acid residues that determine whether or not a given KIR can see a given HLA class I molecule.

 

So one of these epitopes, as we call them – and if they were originally defined on a serological basis because specific antibodies could recognize them – so one of these epitopes is referred to as Bw4; these are epitopes that we mainly see on HLA-B molecules – not all – so depending on the population, human population, may be from 40 to 60 or 70% of HLA-B molecules will have this Bw4 epitope. Some HLA-A molecules also bear the Bw4 epitope. So that’s what some KIR molecules, specifically KIR3DL1, is seeing is Bw4.

 

The results of the study that I talked about today and what we saw is in this African-American multiple sclerosis cohort, individuals that have both 3DL1 and HLA alleles with the Bw4 epitope appear to be protected from multiple sclerosis. And so we see higher frequencies of this combination in our control population relative to patients. So that suggests a protective effect of that combination, 3DL1 plus Bw4.

 

MSDF

Where do you see the research going from here?

 

Dr. Hollenbach

Right now the data that we’re looking at is strictly in terms of carrying frequencies for these particular genes. So these genes are actually highly variable at the allele level, so any given gene like KIR3DL1 has many, many variants that are already known, and likely many variants that we haven’t identified yet because the technology has not been there. The technology is just about now caught up to the point where we are able to examine at the sequence level the variation within these specific KIR genes, and so I think that that’s really the next step. And we’re actually taking steps to start examining this cohort and others in terms of this fine-grained variation in the KIR genes.

 

MSDF

Very good. Thanks.

 

[transition music]

 

Thank you for listening to Episode Thirty-Four of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

[intro music]

 

Host – Dan Keller

Hello, and welcome to Episode Thirty-Three of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. Pierre-Antoine Gourraud about the function of human leukocyte antigens and their role in MS. But to begin, here's a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Early in January, the journal Nature Reviews Neurology published a highlights issue of research advances in MS in 2014. The milestones included successful phase 2 trials for simvastatin in progressive MS, new clinical phenotype categories, and more. We summarized each of these advances, supplemented with interviews from some of the authors. Go to the “News and Future Directions” section of our website and click on “Top 8 MS Research Advances of 2014” to read it. And please do make use of our comment section, especially if you believe that we – and Nature Reviews Neurology – failed to list any equally important advances.

 

Dimethyl fumarate, also known as Tecfidera, may lower CD8-positive T cells in patients with MS, according to a new study out last week. This news follows an earlier story of a patient who died of complications from the rare brain infection, progressive multifocal leukoencephalopathy, or PML, after taking dimethyl fumarate. The drug is known to lower leukocyte levels, including lymphocytes, but many patients are able to maintain normal white cell counts while on the drug. This study showed that even patients with normal leukocyte counts may have dangerously low levels of CD8-positive T cells. These cells are involved in viral immunity, and lower levels of them may leave the gate open for opportunistic infections, such as JC virus, that causes PML.

 

If you enjoy this podcast and find MSDF helpful, please consider supporting us with a donation. MSDF is run by a small team of three full-time employees and a few regular contributors. We are devoted to bridging the gaps between scientific disciplines to speed the flow of information from the lab bench to the bedside. Our ultimate goal is to facilitate the discovery of a cure. We believe one of the best ways to do that is to bring independent, research-focused news to a professional audience on a platform that fosters discussion and discourse. Help keep us going by visiting our website and clicking on the green “Support MSDF” button next to the “Research Resources” tab on the top right of our screen.

 

[transition music]

 

Now to the interview. Dr. Pierre-Antoine Gourraud is the leader of the translational digital medicine group in the Department of Neurology at the University of California, San Francisco. He’s also a distinguished member of our scientific advisory board. He met with science writer, Cynthia McKelvey, to talk about human leukocyte antigen in MS.

 

 

Interviewer – Cynthia McKelvey

Let’s begin by defining the major histocompatibility complex and human leukocyte antigen; what those are and how they relate to multiple sclerosis.

 

Interviewee – Pierre-Antoine Gourraud

So the MHC, the major histocompatibility complex is one of the most important region of the genome. It’s 1000 of the genomes, 3.6 megabase, but it represent about 1% of the total number of genes. So a region that is very dense in genes that are very, very important in neurological functions. It’s also one of the most polymorphic region of the genome, which mean that there are many, many version, many diversity, a lot of alleles, as we call these different forms of a given gene for that particular region of the genome. Basically, it’s encode for or identity or genetic identity, and it has been studied a lot for transmutation. So for multiple sclerosis, since 1972 has been recognized that something in that region had to do with multiple sclerosis risks or the susceptibility; why people are getting multiple sclerosis whatever or not. So back in 1972, researchers realized that people carrying an HLA-DR2 type were actually more susceptible to multiple sclerosis. So doing that in a very simple and comparative manner, we took a bunch of people that have MS, a bunch of people that don’t have MS, and you just see that people that have MS tends to have more HLA-DR2. At that time, the HLAs so the genes that bears the immunity identity of [?] – very important for transmutation again – they were typed by serological techniques. So we were using antibodies to distinguish different types. Over the years, serology has been replaced by PCR-based technique, molecular techniques, and we are now doing HLA typing by sequencing. And for 30 years basically this result has been confirmed, and many additional findings we find the initial association between the MHC region and multiple sclerosis.

 

MSDF

So you’re looking at a cohort of African American MS patients and comparing them to people of European descent with MS. And, you're seeing some differences in the major histocompatibility complexes with these. And how do those relate to MS? What are they telling you about the disease?

 

Dr. Gourraud

You know, if we're stepping back a little bit, it's very important to get very large samples to do genetic studies. The more people we are looking at the easier the findings easy to find alleles. So UCSF and other groups in the world have been organizing to coordinate their effort in structuring the International Multiple Sclerosis Genetic Consortium, IMSGC, and we have been really, really successful in gathering large number of MS patients of European ancestry, as well as controls. Within that consortium, UCSF and Dr. Cree and Dr. Oksenberg, have been pushing an effort to coordinate as well African American cohort of MS patients. So we have been working on that, and for the past two to three years we have done a tremendous effort to actually type the HLA of these patients and these controls. And we have gathered more than about 1600 African American MS patients – and we are still collecting them – and roughly 2000 African American controls to do the comparison.

 

So the first thing we want to do is to see if we are confirming what we see in the European patients – and that is true – we have found  HLA-DRB1 15:01, 15:03 as a specific allele for African American. The HLA-DRB1 03:01 is also to some extent a risk allele in African American. And we also confirm that in the class I HLA-02:01 has a protective effect on MS. So, it's not necessarily obvious, because some of these alleles are actually not found in people of African ancestry, and they also have a much larger diversity. So we are starting to accumulate evidence showing that other alleles that are not present in the Europeans are associated with MS risk. And that’s a very important finding, because now we are in a position where we're going to find structural, functional commonalities between the African American alleles and the European alleles that are both associated to MS.

 

MSDF

And where do you see the research going from here?

 

Dr. Gourraud

So one also very important topic that's being working on both in Europeans and African American is trying not to consider HLA on its own, even if we have really put a lot of samples and money and effort in that, but also consider another very complex family of genes that interact with HLA. These are called KIR (K-I-R), and they are receptor at the cell surface of NK cells, the natural killer cells that have a very important role in immune regulation, and it has been reported that NK cells are actually present in the brain in active MS lesions. So we looked at these two system as potentially interacting to define the risk of MS. So we started typing also for these KIR genes in our African American to be able to study at the same time the MHC or the HLA genes, the KIR genes on a different region of the genome, and also the rest of the genome where we've used a simple marker called SNP.

 

MSDF

That’s great. Thank you very much.

 

Dr. Gourraud

You’re very welcome. Thank you.

 

[transition music]

 

Thank you for listening to Episode Thirty-Three of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

[intro music]

 

Host – Dan Keller

Hello, and welcome to Episode Thirty-Two of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. David Holtzman of Washington University in St. Louis about how a protein implicated in Alzheimer’s disease may also have a role in MS progression. But to begin, here's a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

We recently added a new data visualization to our growing collection. This one organizes every ongoing MS clinical trial—142 of them—into an interactive bubble chart. The size of each bubble represents the sample size of the trial, and the color indicates if the compound has been used to treat MS before. You can organize the chart 10 different ways, including by phase, compound, and sponsor. Go to the “Research Resources” section of our page and click on “data visualizations” to view it.

 

Yet another Phase 2 trial on autologous hematopoietic stem cell transplant was published last week. We reported on this trial’s results and how it was different from previous trials we covered. Like the last two studies we reported on, this current study yielded very encouraging results. To view all of the stem cell stories, go to the “news and future directions” section of our website and look for any story with an image of a mouse in a little white lab coat.

 

New research from the journal Neurology suggests that imaging measurements of the spinal cord and retina independently correlate to disability. Specifically, damage in the two structures was related to visual acuity and to the patient’s ability to discern vibration sensation. The authors suggested that clinicians may want to incorporate scans of the spinal cord and retina into their routine practice.

 

[transition music]

 

Now to the interview. Dr. David Holtzman is Chairman of the Department of Neurology at Washington University. He met with MSDF senior science journalist, Carol Cruzan Morton, at a recent Keystone meeting in Taos, New Mexico, to discuss how his work on apolipoprotein Ein Alzheimer's disease may be relevant to MS.

 

Interviewee – David Holtzman

Most of my career has been focused on trying to understand the pathogenesis of Alzheimer's disease, as well as to develop better diagnostic and treatment methods. However, in doing that – in trying to study the science behind that disease – I've also worked a lot on how normal brain function might be related to not only Alzheimer's disease but just some of the proteins that are involved in both Alzheimer's disease and related disorders.

 

Interviewer – Carol Cruzan Morton

We're at the Keystone meeting on neuroinflammation in Taos, New Mexico, and at the talk this morning you mentioned that there might be a connection between the ApoE and this protein involved in Alzheimer's and MS. Can you talk a little bit more about how that protein works normally in an Alzheimer's, and how you came to make that connection to multiple sclerosis?

 

Dr. Holtzman

Sure. Apolipoprotein E first just in terms of a risk factor for Alzheimer's disease ApoE is present as a protein in all of our bodies. It's made in the brain; it's made by the liver; it's at very high levels in the bloodstream. ApoE plays a role in the bloodstream in transporting lipids around the body. It turns out, though, that if the only thing it did was to transport lipids in the blood then you would probably only need to produce it in the liver so that it was secreted into the blood. But interestingly, it's also produced in several other organs: the ovary, the testes, the brain, and a few other places. So in those other organs, it doesn't probably have exactly the same function that it does when it's made by the liver. But the form of the lipoprotein that's in the brain that ApoE is within is somewhat different than it is, for example, in the bloodstream. It's in what's called HDL or high-density lipoproteins in the brain.

 

MSDF

That's a good thing, right?

 

Dr. Holtzman

That's the good cholesterol. That's the good cholesterol in the blood. In the brain, it's not entirely clear what these HDL lipoprotein particles are really doing. So, for example, if ApoE is absent from the brain of a person, and there are people that have genetic mutations, they have no ApoE in their body…

 

MSDF

Completely gone.

 

Dr. Holtzman

Completely gone. And they have developed serious problems with cholesterol buildup in their arteries because they can't clear big lipoprotein particles from their blood, but their brain is okay, no problem. The people are born normal; brain is okay. And there are probably other proteins in the brain that may be able to takeover for its function in the brain; whereas in the blood that's not the case.

 

MSDF

And when it goes wrong in Alzheimer's, what's happening…?

 

Dr. Holtzman

So that's a different issue. So in Alzheimer's disease, there's no lack of ApoE. In humans, there's three different flavors of ApoE: ApoE2, ApoE3, or ApoE4. And there's a very, very subtle difference between the ApoE2, 3, and 4; just really, really small difference. So brain function in people that are of different ApoE types is normal when they're born and when they grow up and as adults. But for some reason – which we'll talk about in a moment – when people have the ApoE4 form of ApoE, it causes a higher risk for Alzheimer's disease probably because it's promoting the buildup of one of the proteins that's really important in causing Alzheimer's disease earlier. So this amyloid protein that builds up in Alzheimer's is strongly influenced by the form of ApoE that you produce. So if you make the E4 form, it's probably because amyloid doesn't get cleared away as well; it builds up earlier. And if you have the ApoE2 form, which is protective against Alzheimer's disease, it pushes out the development of amyloid deposition until very old ages, if ever. That may be something that's related to Alzheimer's disease that's distinct from what it might do in other diseases of the brain like MS, for example.

 

MSDF

How did you make that connection to MS?

 

Dr. Holtzman

Right. So over the years, there's been a number of scientists and physicians around the world who have studied the many possible functions of ApoE in the body. And for gosh it's been about 30 years or so, there's been reports that one of the things that ApoE does is to influence inflammatory cells: T cells, macrophages, etc.

 

MSDF

All over the body or in the brain and spine?

 

Dr. Holtzman

Yeah, in different locations actually. It's never been completely clear exactly what ApoE is doing to the immune system. A lot of studies individually show effects, but it's not entirely clear what it's doing. And so, I got interested in this personally a few years ago there was a prominent paper published suggesting that one of the things that ApoE does to the immune system outside the brain is to help present antigens to the immune system if they contain lipids. And so, that caught my attention because, one, ApoE carries lipids. And just naively I thought well if it helps present lipid antigens in multiple sclerosis the antigens that are being attacked generally are the lipid related antigens.

 

MSDF

The myelin.

 

Dr. Holtzman

The myelin, right, exactly. So I thought well that seems, you know, maybe there's something to this that one could study in relation to MS because of that.

 

MSDF

And then how did you go about asking those question? Where did you start?

 

Dr. Holtzman

Basically, I thought alright, well a lot of people who work on MS if they use animal studies use the model EAE. So we thought well some of my colleagues at Washington University have been using the EAE model for years – like many people have – and so we thought well the obvious experiment to try first is just compare animals that express ApoE in their body versus those that don't. And simply ask the question is there anything different about EAE in an animal that lacks ApoE or not? And so, first, we started working with Anne Cross and then later with Greg Wu together who are experts in using animal models of MS. And ultimately published findings showing – and a few other groups have worked on this, as well – showing that there appears to be decreased clinical severity of EAE in a slightly later onset of disease in animals that lack ApoE.

 

MSDF

And what does that tell you…there might be a role or…?

 

Dr. Holtzman

Obviously many other studies would need to be done to know if it has a role in human MS. But once we found that, particularly Greg's lab began to ask the question well if that's true what's the mechanism? If there is a mechanism that we could hone in on, is that something that seems logical based on what we actually know about ApoE already? And so, the things that kind of came out of our first series of studies was that – unlike what I initially had thought from this earlier paper – it doesn't appear that ApoE is modifying antigen presentation of cells or the ability of T cells to react against the brain. But something once T cells do get in the brain to attack myelin and other components, there's something about that ApoE is acting on at that point. It could be that it's involved in allowing the myelin to repair, or alternatively it could be that when T cells get into the brain and interact with other cells in the brain – like other immune cells like microglial cells or dendritic cells – that that interaction is altered by ApoE within the brain. That might make sense given that ApoE is highly expressed by macrophages outside the brain, and inside the brain it's highly expressed by what are called activated microglial cells. So kind of the macrophages of the brain. So that's where we kind of are now, and I think there's a lot more studies that could be done to really understand both that interaction as well as whether human ApoE causes the same effect that we saw in animals as mouse ApoE. Because they're not exactly the same; they're similar but not the same.

 

MSDF

Is there other evidence connecting ApoE or its various forms with MS?

 

Dr. Holtzman

There are human studies that have been done trying to ask the very simple questions of is the ApoE4, which is a risk factor for Alzheimer's, is that over represented in MS? Or is the ApoE2 form, which is under represented in Alzheimer's, is that protective against MS? And the studies on this some have suggested effects, some haven't. There's no clear answer. But I think if ApoE is involved in MS, it would be less likely to be involved in whether you get MS but more likely involved in the progression of the disease. And I know in the MS field one of the big areas now – now that there's so many studies and as well as treatments that have emerged that are quite effective at suppressing the initial phases of MS, the immune response phases – a lot the work is going into understanding this prolonged progressive phase of MS. And that's where ApoE could be important in sort of the repair and recovery of neurons and axons, for example. Because the fact it transports lipids between cells, maybe it has something to do with recovery of the brain after injury. And that's been speculated on for some time, although not as much work on that has been done in MS.

 

MSDF

Has it been speculated on in MS or MS and Alzheimer's both or…?

 

Dr. Holtzman

No, it's been speculated on after a variety of different brain injuries that it plays a role in redistributing lipids in the brain after injury, and that might be promoting recovery. So one possibility that still hasn't really been tested that I'm aware of in models of MS or in human MS is to whether that really happens for ApoE in the human brain or animal models.

 

MSDF

Can that be tested now?

 

Dr. Holtzman

Absolutely, absolutely. Those are some of the studies that I think are really critical as the next step.

 

MSDF

Is it conceivable that the body of knowledge for Alzheimer's research on ApoE might yield a treatment for progressive MS?

 

Dr. Holtzman

It's possible. I mean a lot of the understanding of what ApoE might be doing in the brain has really expanded because people have been studying Alzheimer's disease and its relationship with ApoE. So I can't imagine it wouldn't help with that because we've learned a lot so far.

 

MSDF

Are there other treatments in the pipeline for Alzheimer's related to ApoE?

 

Dr. Holtzman

There are. There's not too many things yet that have reached human trials, but there are groups trying to alter the level of ApoE in the brain or to alter its receptors in the brain as potential treatments for affecting Alzheimer's disease. So yeah, I mean those are the kind of things, as they advance, depending on what's found in regard to the relationship between ApoE and MS could be tried in MS. I don't see why not.

 

MSDF

That's interesting. What else should I be asking?

 

Dr. Holtzman

I think what scientifically what I think is really important to still sort out in this area is that when the innate immune cells of the brain – the microglial cells or even macrophages when they get into the brain – they produce tremendous levels of ApoE when that happens. And I think understanding what that protein is really doing in that setting could provide insight into future treatments. So that's what I think is really fascinating to try to understand.

 

MSDF

Well if it happens in Alzheimer's, as well, it happens before the blood-brain barrier breaks down and then after it, it sounds like.

 

Dr. Holtzman

Well, in MS, it's probably occurring after there's cell entry into the brain. But the upregulation of ApoE by these innate immune cells is much higher in MS than it is in Alzheimer's disease.

 

MSDF

Oh, is that right?

 

Dr. Holtzman

Yeah, yeah.

 

MSDF

That's interesting. That's even more interesting.

 

Dr. Holtzman

Yeah, I know. That's why it's really, really fascinating. I think one of the figures from the paper that we published last year from Greg's lab showed that the level of ApoE increasing in microglial cells versus similar cells that are present in the spleen of an animal is like 25 times higher in the setting of an EAE model than normal. So it's really, really high. Is it really doing anything, or is it just a byproduct? I suspect it probably is doing something. So that's what I think would be really interesting to figure out.

 

MSDF

Thanks. Well I appreciate your taking time out at the Keystone meeting to talk with MS Discovery Forum.

 

Dr. Holtzman

Yeah, it's great. Well good luck. MS is such a…the treatments that have been evolving are so exciting compared to Alzheimer's disease where we don't yet have good treatments. So I think there will be soon, but I think it's a great opportunity to even advance for ...

 

MSDF

Is there a chance that the reverse could be true? That treatments existing for MS would be helpful in Alzheimer's?

 

Dr. Holtzman

That's a good question. I don't know if any of the frequently used ones where you're preventing cell entry into the brain necessarily would be useful for Alzheimer's. But like one of the new drugs, Tecfidera, this oral medication does do some interesting things to cells in the brain that might be useful in a disease like Alzheimer's. So maybe there will be some things that we can translate.

 

MSDF

I appreciate it. Thank you so much.

 

Dr. Holtzman

Thank you.

 

[transition music]

 

Thank you for listening to Episode Thirty-Two of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

[outro music]

 

 

 

 

 

[intro music]

 

Hello, and welcome to Episode Thirty-One of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. Lloyd Kasper about the gut microbiome and its role in MS. But to begin, here is a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Last week our parent organization, the Accelerated Cure Project, launched its latest endeavor called “iConquerMS.” iConquerMS aims to enroll 20,000 people living with MS to play an active role in research, empowering them to securely submit their health data, influence the studies that are carried out by the initiative, and stay informed about the research. Visit iConquerMS.org for more information.

 

Vision and sensorimotor problems go together in some MS patients. A recent publication in the journal Neurology examined the relationship between MRI measures of the spinal cord and retina in patients with MS. The investigators found some correlation between the two types of metrics, but they also found that damage in each structure had independent relationships with disability. Read the full story in our “news and future directions” section.

 

And lastly, our previous podcast contained an error. We mentioned a story about a proof-of-concept study of a novel way to monitor lesion repair. However, the story was withheld from publication due to a delay in the release of the research article. The story is now live on our website.

 

[transition music]

 

Now to the interview. Dr. Lloyd Kasper is a faculty member of the Geisel School of Medicine at Dartmouth College. He met with MSDF Executive Editor, Bob Finn, to talk about his research on the gut microbiome and MS.

 

Interviewer – Robert Finn

Dr. Kasper, welcome.

 

Interviewee – Lloyd Kasper

Thank you.

 

MSDF

So to start, why on earth would someone interested in a neurological disease such as MS concern himself with bacteria in the intestines; what’s the connection?

 

Dr. Kasper

That’s actually a very valid question. And the answer to that question is pretty straightforward, is that there’s a very clear brain-gut access so that the brain talks to the gut primary modulating the physiology of the gut through secretion of a variety of molecules, vasoactive proteins, etc. That in turn affects the motility of the gut. By affecting the motility of the gut, you also affect everything that’s inside the gut, which is – as you mentioned just previously – the 100 trillion bacteria that each and every one of us in this world has. And those bacteria in response to the changes in motility shift their behavior, because these are living organisms, and they secrete a wide range of metabolites.

 

For the purposes of simplicity, you can look at those metabolites and the effect of those various metabolites on the immune system, taking into account that the gut is the largest immune system in our body – 80% of our immune cells are in the gut. So you’ll have this clear interaction between the brain, its activity physiologically on the gut, and the gut’s activity on the bacteria, and then the bacteria’s activity back on the immune system which leads to issues related to the brain.

 

MSDF

So you partly answered my next question. There are microbiomes in other places besides the gut – the skin, the urinogenital tract, etc. Do those other microbiomes have any affect or any relationship to multiple sclerosis, do you think?

 

Dr. Kasper

First of all, the association between the gut microbiome and MS has not yet been fully established, there’s experimental data that would suggest that there is a relationship between the two but that’s still at the experimental level. There really has been very little exploration of the other microbiomes within the body. Remember, the microbiome is not just the microflora. What the microbiome is is the genome of the flora in its relationship to the genome of its host. So when you look at the genomics of MS, for example, in the host – which there’s a lot of work that’s being done – you’re only looking at a fraction of the genetic material that’s involved in this relationship between the gut and the body that it’s in OR any of the other sites that we have microflora – our mouth, as you pointed out; our ears – inside of our ears; our lungs. Those are all areas that bacteria in our body exists in balance with us to achieve a homeostasis. The reason for looking at the gut microbiome is that because it’s the largest, probably the most complex as well.

 

MSDF

So you focused much of your attention on a single bacterial species. Let me see if I pronounce this correctly – Bacteroides fragilis– am I close?

 

Dr. Kasper

Correct.

 

MSDF

And a single substance that it produces, polysaccharide A, or PSA – which has no relation to prostate specific antigen. Why are you focusing on that species and that product?

 

Dr. Kasper

Well, there is mounting evidence that there are several phyla that colonize the gut. The two major phyla of interest are Firmicutes, which are gram-positive aerobes, and Bacteroides, which are gram-negative anaerobes. I’m talking about at the phyla level over which there is no kingdom, phylum, class, order, family, genus, species. Under each one of those phyla there are many different species. We’ve focused in on primarily Bacteroides because Bacteroides fragilis is a very common commensal that essentially inhabits in the neighborhood of 80-90% of all mankind in the world. Bacteroides as a phyla has been associated with the induction of regulatory T cells. Regulatory T cells live in the colon, in and around the colon, and that’s where Bacteroides live. And it’s been shown that Bacteroides as a phyla have the capacity to drive regulatory T cells.

 

The reason it’s important in MS is because there is a known deficit in the regulatory T cell population in patients with MS. And we chose Bacteroides fragilis because of all the Bacteroides species, that’s the one that we actually know most about immunologically. There’s at least 20 or 25 years’ worth of very, very important data that shows how this particular molecule, this polysaccharide A – and it’s a polysaccharide, it’s not a peptide, it’s a polysaccharide – how this polysaccharide can drive the immune system to a regulatory phenotype that’s associated with the induction of regulatory T cells, production of IL10, all those factors which are important in MS which we know are deficient in those with MS.

 

MSDF

When you say drive the immune system, drive T regs, what do you mean by that?

 

Dr. Kasper

Basically, these bacteria have the capacity to convert effector cells, which would be CD4 positive CD25 negative cells to a regulatory phenotype, which would be CD4 CD25 positive associated with sort of the standard-bearer of regulatory cells, which is Foxp3, which is a nuclear antigen that’s been characterized with it. So this molecule has a remarkable capacity to do that both in vivo and our studies show you can do that actually in vitro as well. So you can take cells that are negative that would be considered naïve or effector-type cells, culture them with this PSA molecule, and convert them to regulatory cells which we know are important in controlling the disease.

 

MSDF

So remind me whether you want more or fewer of these regulatory T cells.

 

Dr. Kasper

It depends where you are in life. To give you sort of a circumstantial argument, we know that Firmicutes, which is that other major phyla, has been associated with a number of disease states, including obesity – just to name one – atherosclerosis, but we also know that the Firmicutes have the capacity to drive IL-17. The regulatory T cells are cells that control the IL-17 response, so it’s important to have regulatory T cells to control the IL-17. We know experimentally that IL-17 drives the experimental form of multiple sclerosis EAE, and there is mounting data – and pretty conclusive, I think – MS is probably at least in part driven by IL-17 cells. So you need these regulatory T cells to control that IL-17 response which is probably being driven by the Firmicutes population. And I’m oversimplifying this, because you remember, you’ve got a hundred trillion cells downstairs making god knows how many different metabolites with over a million genes. So what I’m presenting to you is a very simplified version of this remarkably complex organ.

 

MSDF

So is this leading toward clinical utility for polysaccharide A?

 

Dr. Kasper

We hope so.

 

MSDF

Can you tell me more about that?

 

Dr. Kasper

Well, again, our experimental data – at least in EAE – demonstrates that animals that have been induced with EAE are protected by this polysaccharide. Animals that have EAE, we can therapeutically treat them with this. So this is the first demonstration that a commensal-derived bacterial product that’s within essentially pretty much all of mankind has the capacity to induce regulatory T cells. We don’t know if MS patients are deficient in this or they have the genetic makeup that they can’t respond to it, or whatever it may be. As I said, there’s a real complexity. But the simple observation as we know is that if we take animals that are susceptible to EAE and we treat the prophylactically or therapeutically, we’re able to protect them very, very nicely against the disease process.

 

And now we have preliminary data in humans that we can take human cells in vitro out of a person and we can drive those human cells from an effector CD4-positive CD25-negative phenotype to a regulatory phenotype by this molecule; just five days of exposure and you see this very nice conversion that’s associated with increased IL10 protection, etc.

 

MSDF

Do you imagine that the PSA molecule itself, if drug development goes on, is there any chemistry that needs to be done before it might possibly be therapeutic?

 

Dr. Kasper

A lot of the chemistry has been done. We have a pretty good idea of what the molecule looks like, it’s a repeating polysaccharide chain. And we know what the conditions are at least in animals as far as innate response molecules – TLRs, toll-like receptors, etc. So as far as the molecule itself, I think we have a pretty good understanding. As I said, there’s about 20 years’ worth of very solid biology behind this molecule. So how far we are away from the clinic at this point is a matter of time, resources, and money to be able to move it from the experimental stage that we’re in into the clinic.

 

MSDF

So you’re not the only research group working on the connection between the gut microbiome and multiple sclerosis. I wonder if you can talk a little bit about how your research fits in with the various other approaches that are going on.

 

Dr. Kasper

Our research has been focused primarily on immune regulation – how to get the disease under control, at least experimentally and hopefully in MS patients. Most of the other labs are looking primarily at what bacteria or bacteria populations are responsible for affecting the disease; what’s driving the disease. We’ve sort of kept away from that because we were fortunate in being able to find this one molecule derived from a bacteria, as I said, that much of mankind is colonized with, so we’ve been focused mostly on how to regulate the disease rather than what’s driving the disease.

 

MSDF

Now, as you know, there’s been a lot of talk and controversy about the role of diet in multiple sclerosis. Do you think that gut bacteria and the substances they product may provide that missing link connecting diet with MS.

 

Dr. Kasper

I think that diet’s going to turn out to be one of the more critical environmental factors that’s associated with the disease process.

 

MSDF

Can you say a little bit more about that?

 

Dr. Kasper

Well, if you look at all the risk factors that we know for MS, that being genetics, obesity, smoking, gender – just to name a few – there’s about six or seven of them. Every one of those risk factors is associated with the microbiome. The common denominator for all the risk factors we know so far in MS is the microbiome, and that includes genetics. As I said, the microbiome is a two-way street; it induces things in us and we do things in turn to it, so it’s a binary system. So our speculations – and we just had a paper published in FEBs – Federation of Experimental Biology – is we’re speculating that the gut microbiome is the major environmental risk factor for MS because it includes all of the known risk factors.

 

So how can you adjust that? Well, the most logical way is diet, right, because it’s the change in the human diet over the last hundred years that may be accountable for the rise in the disease process. It may also be the change in the diet in Africa as well as Asia which were relatively unknown for MS, but now the incidents in Asia as well as in Africa is approaching about the same as it is in the United States and Europe. So as diet has changed, so has the incidence of the disease gone up. So I’m speculating that diet will turn out to be a very important factor in controlling the microflora, which in turn allows for the balance, the homeostasis, in individuals.

 

MSDF

Well, very interesting. We’ve come to the end of our time, but is there anything you’d like to add, any important questions that I haven’t asked that I should have asked?

 

Dr. Kasper

No. I think the question about the diet, you know, where do you go from here? Because it’s going to take years and years for scientists and clinicians to sort out what’s actually going on in the microbiome. We’re at the tip of the iceberg in this really, because not only is it the immunology that’s important but it’s the physiology and the physiologic changes that the gut microbiome may be creating in people. So as we get better definition of what activities are going on in the microbiome, the greater the likelihood we’ll have of understanding a whole range of human diseases. And not just MS, but that’s all other autoimmune diseases, cancer, obesity, you know, it’s a long list.

 

And it may ultimately turn out that it’s a clue to our understanding of cancer, for example, because as the microflora shifts as we grow older – which it does – perhaps what we’re seeing is that early on we have bacteria that induce inflammatory processes – which is why MS is a disease of young people – that tends to peter out as you get older. It’s a well-known thing. It doesn’t go away but it tends to peter out. But that may be parallel to the shift in the microflora that’s going on. So early on in the western diet you’re having mostly Firmicutes. As we get older that shifts to more of Bacteroides, which has more regulation. What does more regulation equal? Well, you’re down-regulating the immune system, and as we get older what do we become susceptible? Cancer. So there’s a real balance that’s going on here. And I think a lot of the clues to human biology as far as disease state are going to ultimately be related to the microbiome.

 

MSDF

Dr. Kasper, thank you very much.

 

Dr. Kasper

Thank you.

 

[transition music]

 

Thank you for listening to Episode Thirty-One of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

 

[intro music]

 

Hello, and welcome to Episode Thirty of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. Seema Tiwari-Woodruff about estrogen in animal models of MS. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Last week, we reported on the results of another clinical trial for hematopoietic stem cell transplantation in relapsing-remitting MS. Compared to the “halt-MS” trial, which we reported on in January, this study used a less aggressive conditioning approach. Patients involved in the study demonstrated improvement in EDSS scores, and eighty percent of them were relapse-free at four years. The results raised important questions about how to prep MS patients for the transplant. Visit our “News and Future Directions” section to read the full story.

 

A recent study published in the Multiple Sclerosis Journal demonstrated a potential new way to monitor lesion repair using standard MRI techniques. Clinical trials usually look for new lesions in brain scans to monitor drug efficacy. Lead author, Daniel Reich, told MSDF it’s more important than ever to be able to visualize changes in tissue since drug development is shifting towards neuroprotection and repair.

 

We’re also pleased to announce that Daniel Reich is one of two new members of our Scientific Advisory Board. Dr. Reich is the director of the Translational Neuroradiology Unit in the National Institute of Neurological Disorders and Stroke, part of NIH. Our other new board member is Deborah Backus, an expert on rehabilitation who is Director of Multiple Sclerosis Research at the Shepherd Center in Atlanta, Georgia. Read their full bios in our “Who We Are” section under the “About Us” tab.

 

[transition music]

 

Now to the interview. Dr. Tiwari-Woodruff is an associate professor of biomedical sciences at the University of California, Riverside. She met with MSDF editor-in-chief, Bob Finn, to talk about her research on estrogen and multiple sclerosis.

 

Interviewer – Robert Finn

Dr. Tiwari-Woodruff, welcome.

 

Interviewee – Seema Tiwari-Woodruff

Thank you.

 

MSDF

So what is the connection between estrogen and MS?

 

Dr. Tiwari-Woodruff

It’s an interesting connection between estrogen and MS, because estrogen is actually a part of life in a way that our brains require it, our bodies require it at every moment of our life, I should say. Many years ago it was found that relapsing-remitting patients had less relapses when they were pregnant, and the causes of that was potentially estrogens – high levels of them – or progesterone or vitamin D. Many researchers went ahead and looked at those high levels of pregnancy estrogens called estriol and found that high levels of estriol were the reason why these women patients had lower levels of MS symptoms.

 

So eventually down the line, estrogens were parsed out of which estrogen was better. And it turns out that one type of estrogen, which is the estrogen of the alpha, is more immunomodulatory – it actually suppresses the immune response – and that is probably what makes MS symptoms better versus estrogens of the beta ligand was known not to have that much immunomodulatory effect; instead, it was actually directly neuroprotective. So estrogens of the alpha and beta both seem to have an effect on various cell types which are involved in multiple sclerosis.

 

MSDF

So if estrogen seems to be protective in pregnant women with MS, why not just use estrogen, or an analog like estriol or estradiol, as a treatment?

 

Dr. Tiwari-Woodruff

That’s a very good question. And, first, these therapies were thought that we were going to use those first, and a lot of clinical trials were going through with that. But what happens with high levels of estrogen is there are two things which are important to know. One is they have a feminizing effect, and the second one is they have a preponderance for causing uterine cancer or breast cancer. So you don’t want to stimulate those two types of cancer. So high levels of estrogen could be dangerous in that aspect. So that is why we don’t want to use that as potential therapy.

 

MSDF

So you’ve done a lot of work with a specific estrogen receptor agonist called indazole chloride. First, tell me how you came upon this compound.

 

Dr. Tiwari-Woodruff

So estrogens of the beta ligands are not just being looked at for multiple sclerosis, they were being looked at as a potential therapeutic for menopause – hot flashes included – rheumatoid arthritis, and other impairments like prostate cancer, etc. So there were quite a few chemists who were coming up with various different types of estrogen receptor beta ligands. So while I was doing my work with mouse models of MS in generic estrogen receptor beta ligand, which was the DPN – diarylpropionitrile – a study came out which was actually on indazole chloride which was developed by a chemist, John Katzenellenbogen; he’s done a lot of work on developing these molecules. And this particular compound showed that it decreased activation of astrocytes and microglia; this was published in Cell a few years back. And we met at a meeting, John Katzenellenbogen and myself – we were giving a talk at the same time in a meeting in Stockholm – and we decided to talk to each other. And he said, “Your research is very intriguing on estrogen receptor beta ligand, would you like to try this out?” And that’s how I got my hands on the indazole chloride. And we did some preliminary studies and showed good results. Then we decided to embark on a full-fledged study which was published in PNAS.

 

MSDF

So you used indazole chloride in two different mouse models of MS, and you used it both prophylactically and in mice that are already showing symptoms. What did you find?

 

Dr. Tiwari-Woodruff

So prophylactically when you use a compound, you are actually trying to see if you can inhibit the symptoms which are going to come up when you induce a disease, and that is all good. But when you are talking about patients who come to see the doctor, they’re always coming in with symptoms, so they already have the disease ongoing. So the second paradigm where you give the drug when the disease symptoms are already there is closer to what humans are going to be able to see. So the nice thing about indazole chloride was that, prophylactically, definitely it made the mice better, but therapeutically also; they were able to decrease the disease symptoms by nearly 50%.

 

MSDF

What is the significance of the fact that it seems to work on two different mouse models of MS?

 

Dr. Tiwari-Woodruff

So when you’re looking at a drug especially in a disease like multiple sclerosis which has two major components – one is inflammatory component and another one is a neurodegenerative component – if you can show that this drug is working in one way or both ways would be very useful for developing better drugs or better treatments. So what we did was when we treated the mice with indazole chloride, in one mouse model which is the experimental autoimmune encephalomyelitis which contains both the inflammatory and the neurodegenerative component, we saw a decrease in the disease symptoms. But we couldn’t tell if the indazole chloride was working in the inflammatory component or the neurodegeneration component, because it showed effect on both.

 

So we went to a second mouse model which is the toxic cuprizone diet model which doesn’t have a primary inflammatory component. The disease starts with oligodendrocytes, the cells which make the myelin. They die when you feed this diet to the mice, so they have massive demyelination in regions of the brain. When we gave the drug during the remyelination phase, we found that indazole chloride was able to remyelinate the axons better when the drug was present versus when it was absent. So this actually showed us that indazole chloride has two arms to it. One, it inhibits the inflammatory component and the second, it inhibits the neurodegenerative component independent of the inflammatory component.

 

MSDF

Is it also sort of confirmatory? The EAE is not a perfect model of MS and neither is the cuprizone mouse model, but does it make you feel better that these two completely different models are showing similar effects?

 

Dr. Tiwari-Woodruff

Absolutely, you really hit the point where… We are always looking for the best model for multiple sclerosis, but because the disease is so complex no one model can be said that it’s 100% mimicking multiple sclerosis. So for us to see that demyelination which occurs both in EAE and the cuprizone model was improved – we actually saw remyelination in both models – really gave us hope that this drug could be directly acting on oligodendrocytes which are forming the myelin, which is the cause of major mode of dysfunction in multiple sclerosis.

 

MSDF

So does indazole chloride help these mice a little bit, or does it help them a lot?

 

Dr. Tiwari-Woodruff

So that’s a very good question. Similar to what you might see in the patient population, in the mouse model of MS, especially in the EAE model, the disease is not consistent. So the lesions which appear in the brain of EAE animals are very diverse, unlike the cuprizone model where the demyelination is very consistent. So when you’re looking at these mice, especially in the EAE cohort, if the animal is really, really sick, you actually see the disease symptoms go down just a little bit. But if the animals were sick to the middle level, they actually showed a bigger difference, they showed better recovery. And we hypothesize that the axons which have been injured to the point of no return, if the axons have been demyelinated and injured, it doesn’t matter now when you give them therapeutic drugs, these are not going to improve. So there are certain number of axons in the brain which drop out and we don’t see recovery in those. But said that, overall we still saw a significant increase with indazole chloride treatment in both models.

 

MSDF

Have you done histology?

 

Dr. Tiwari-Woodruff

Yes. We’ve done histology, we’ve done electron microscopy. And we do one more thing my lab is very good at, we do electrophysiology. Because one of the things we always think is when you look at remyelination you can see myelin coming up, but is the myelin functional? If the axons can conduct faster or better, then you know that the myelin which has covered the axons is functional. So we do all three. And we also include behavioral testing. So one of the tests we included which a lot of people use is a Rota rod; it’s a motor test to show that the mice can stay on the Rota rod much longer after treatment with indazole versus just the vehicle.

 

MSDF

Do you see any side effects?

 

Dr. Tiwari-Woodruff

So that’s interesting. We did not see any side effects in these mice. Agreed, we treated them up to 60 days, we haven’t treated them longer than that, plus we were giving them at a 5 mg/kg/day concentration. So we didn’t see any kind of toxicity. But said that, we still need to do those studies in a thorough way before we can safely say that they had no side effects.

 

MSDF

So what’s next in the development of indazole chloride as a potential MS treatment?

 

Dr. Tiwari-Woodruff

So indazole chloride is a good target. And while these studies were going on last year, John Katzenellenbogen and myself, we were talking about how are we going to proceed with this because we were seeing really good results; this is even before I published the paper. And he said what would you like to do? And one of the things we said was is it possible to make better analogs of this compound which are going to be more specific, could be used in a lower concentration and may have a better therapeutic outcome?

 

So he came up with four analogs which he has sent to me, and we did some preliminary studies to see if they were toxic to cells in culture, because that’s the first thing you do. And they have no toxicity in cells, they actually have shown to behave well with proliferation – depreciation of the cell – and we haven’t seen more cell death or less cell death with them. So we are very excited about that. So coming next month, we are actually going to start treatment of EAE animals, and once that goes through the goal is to do toxicity studies on the two best compounds and see if we can find a company so we can have a backing on these drugs for potential human trials. It’s a couple years from now, at least – it could be even more – but we are actually moving in that direction.

 

MSDF

Dr. David Baker in a commentary on his multiple sclerosis research blog seemed less than enthusiastic about indazole chloride. He suggested that many compounds seem to work similarly in mouse models. How do you respond to that criticism?

 

Dr. Tiwari-Woodruff

So Dr. Baker has a very good point on saying that there could be many compounds which are good in EAE but they fizzle out and they don’t go up to clinical trial. I disagree on one point where it comes to indazole chloride, because we have precedence of estrogens showing good therapeutic indication in humans; there were clinical trials done in UCLA where they showed that there was improvement with estriol treatment. And estriol does target both ER-alpha and ER-beta – ER-beta a little more than ER-alpha – so I’m very confident that what we are seeing with estrogen receptor beta is not a fluke. And because it’s a steroid and a small molecule, it does not seem to have a lot of toxicity involved which could be somewhat which is brand new. So we’ll see. I hope Dr. Baker’s wrong and we do manage to get this drug to human patients and we see therapeutic efficacy in them.

 

MSDF

Dr. Baker also said that a critical experiment had not yet been done. And let me quote from his blog post. He said, “The development of demyelination should be allowed to occur after this damage has abated, then punitive remyelinating drugs should be given.” How do you respond to that?

 

Dr. Tiwari-Woodruff

Very good point made by Dr. Baker, but I have actually addressed those in the PNAS paper. We part off particularly this aspect of the disease. So the prophylactic treatment was before the disease started; that is what he’s mentioning in the blog. The second part is what is important where EAE disease was induced, and after peak disease had occurred we gave the drug, indazole chloride. At the peak disease, we actually see increased inflammation, but alongside with that we see demyelination and axon degeneration. So the damage has already started. The drug treatment after that is what caused the disease to get better. We saw increased conduction, we saw increased remyelination, and less axon damage.

 

Similar to that, we also did the experiment in cuprizone. The treatment paradigm was as such: We actually had nine week of demyelination ongoing in the cuprizone model, which is very chronic; it’s chronically ongoing where you have quite a bit of damage of the axons and you have acute demyelination. During the remyelination phases where we gave the drug either to one group and vehicle to the other group, what we saw was that the drug treatment, indazole chloride, actually increased remyelination and decreased axon damage. So I think Dr. Baker was trying to make a point on we haven’t done the right experiment, but I think we have done the right experiment. And further research with indazole chloride will let us know if this is a good drug or not.

 

MSDF

Dr. Tiwari-Woodruff, is there anything you’d like to add?

 

Dr. Tiwari-Woodruff

I would like to add one more thing. We have actually looked at indazole chloride in optic neuritis – EAE-induced optic neuritis – and we are going to be publishing a paper fairly soon showing that in optic neuritis we see less inflammation in the retina and increased remyelination in the optic nerve. So I’m very confident that it’s not just a phenomenology in one part of the brain which we picked last time – it was the corpus callosum – that we see increased remyelination and decreased damage caused by EAE with treatment of indazole chloride.

 

MSDF

Well, thank you very much.

 

Dr. Tiwari-Woodruff

Thank you.

 

[transition music]

 

Thank you for listening to Episode Thirty of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

[intro music]

 

Hello, and welcome to Episode Twenty-Nine of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. Monica Carson on funding research in MS. But to begin, here is a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Glatiramer acetate and the interferon betas appear to be clinically similar, according to a new study in the Multiple Sclerosis Journal. This study follows on the heels of a Cochrane meta-analysis we covered earlier in 2014 that found similar results. Instead of performing a meta-analysis, though, the researchers of the MSJ article used data from over 3,000 patients in the MS Base database. They found very little difference in annualized relapse rates over 10 years, though glatiramer acetate and subcutaneous interferon beta 1-a did eke out a statistical win over the other interferons.

 

Together, MSDF and our non-profit publisher, Accelerated Cure for Multiple Sclerosis, are committed to speeding the pathway toward a cure for MS. Among the news and resources we provide is a list of more than two dozen tissue repositories, including one maintained by Accelerated Cure. Visit our website and click on the “tissue repositories” button under the “research resources” tab to browse through repositories from all over the globe.

 

Another part of our goal in working faster toward a cure is to provide a place where researchers can share their experiences and expertise with one another and also debate controversial issues in MS research. We encourage researchers and clinicians from all disciplines to log onto our forum and discuss their latest research, techniques, and discoveries. We also encourage you to help keep us up-to-date on your latest work by e-mailing us directly. Send information you’d like to share on job postings, meetings, funding opportunities, or other news to editor at msdiscovery.org.

 

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Now to the interview. Dr. Monica Carson is director of the center for glial-neural interactions at the University of California, Riverside. She met with MSDF editor-in-chief, Bob Finn, to talk about the current state of funding in MS research.

 

[Interview]

 

Interviewer – Robert Finn

Dr. Carson, welcome.

 

Interviewee – Monica Carson

Thank you.

 

MSDF

So let’s stipulate that there’s never enough money available for funding any area of research adequately. On a scale from bad to awful to dire, what is the state of funding for MS research?

 

Dr. Carson

I would say it’s better than maybe other areas, but all areas of research, I feel, are dire, so I do not want to make MS research sound worse. It’s probably actually better because individuals can see the value of research in disease-oriented research programs. So in a worse situation, it’s good.

 

MSDF

So there are essentially three sources of research funding. There’s the government; there are nonprofits; and then there are for-profit companies, mostly pharmaceutical companies in the biomedical area. How are each of these doing in funding MS research?

 

Dr. Carson

There are objectives in all of these. There’s always been a long-term funding priority in NIH NINDS. There’s also out of various objectives that are perhaps nontraditional for those of us who came up as NIH-funded investigators, such as the DOD and various congressionally-mandated research programs. There are much more funding, I think, also in private foundations. Funding in biotech and pharmaceutical, I think, has been the one area that has dropped severely over the years, and that one is not an area that I think one can count on, that is going to be something targeted when you have a proposal. And then you do have to work through the ethics and various other aspects of that.

 

That said, the National Multiple Sclerosis Society has really shown a very nice model of partnering with pharmaceuticals with their Fast Forward program. I’ve served on those panels and they are really wonderful models of projects that are brought in that have sufficient IP – intellectual property – protection of the ideas brought in that could be moved Fast Forward by a partnership with pharmaceutical and the National Multiple Sclerosis Society. So there are targeted areas, but of course it’s going to be very more modest in general funding overall for the average investigator, whereas the more traditional governmental and private foundations are going to be our primary sources.

 

MSDF

How do you account for the drop-off in pharmaceutical company funding?

 

Dr. Carson

Well, I am not an expert in economics, in the costs that it takes to take something to market, but I would speculate that it has to do with the difficulty of getting drugs that work in the brain that pass all the various measures of blood-brain barrier, unexpected toxicities and side effects. And so I think this area of pharmaceuticals has had great expense but great dropouts. So for great expense there hasn’t been a lot of drugs coming out except in targeted areas. I would say recently it’s been very exciting about the therapies that are coming out in MS research.

 

MSDF

So do these three sources – government, nonprofit, for-profit – do they tend to support different types of research?

 

Dr. Carson

Yes, very much so. I think as we very much know, you go to NIH, it’s a good scientific idea, needs to impact health, could be a basic science issue that applies to MS but also might apply to Alzheimer’s diseases, neural inflammation, or a variety of other diseases in childhood. When you get to a private foundation, the private foundation has taken donations or raised money very specifically for a disease, and so different private foundations are going to be focused on how much other research is applied to the disease, but also how translational it is. How important that translational element is going to be specific to the different foundation. But all of the private foundations are going to be very specific that this is not just a good idea, but is a good idea for their diseases, specifically multiple sclerosis.

 

MSDF

So let’s say you are a researcher, possibly a young researcher, searching for his or her first research funding. How do you strategize the search for research funding?

 

Dr. Carson

Very good question. I don’t think there’s one right answer to this and one has to look at one’s own portfolio of research, one’s resources, and what one can actually deliver after one has made a promise in a grant proposal. And I think you need to as a young researcher get advice from senior researchers and investigators in your area in your field to see how to go forward. But very often the best way is to take advantage of the pilot grants, the junior investigative grants that are really targeted to getting you off the ground and can have ideas that are high-risk, high-impact.

 

There are also many of these pilot grants from the private foundations, such as the National Multiple Sclerosis Society has a pilot project; it’s aimed at getting folks to get their early funding in MS to sort of capture them as a long-term MS researcher. So I think the pilot grants are a good way to start to get that bolus of research-funded publications, demonstrate your productivity level so that you get the larger grants from NIH.

 

MSDF

So let’s talk specifically about the National MS Society and Erase MS, which are the two large nonprofits that you’ve been involved with. How do their funding philosophies differ?

 

Dr. Carson

Well, I’m not really ready at this point to talk quite about more about the Erase MS, because I’ve just joined their scientific advisory board and I am about to start participating in their review cycles. And so I think it’s best to go through that cycle a few more times before commenting on that. But I would say it’s going to be very focused. They are also looking at bringing together research centers, and the Erase MS is very much focused on therapies and things that are going to move things forward quite fast. So in that sense, the MS Society is a more longstanding society; it has been on my mind one of the best models of collecting money, giving out money to researchers, making sure the research is very specific to MS. And this goes back to my prior point. Having been on MS study sections, it’s very important for them – this can’t be just a good idea – it has to be applying to MS.

 

So one of the things I think is the other very big difference between these is the MS Society also has a lot of different types of grant funding programs – these pilots which I just mentioned; training grants; transition grants which are very important to the junior investigator which will take you being from a senior post-doc to an independent position; as well as larger grants, 3-year grants, that are sufficient to carry a major project.

 

MSDF

So there’s a perception in the public, I think among scientists as well, that some of the big disease societies spend 90% of their funding on administration and 10% on funding research. How does the National MS Society stack up in that regard?

 

Dr. Carson

I would say the MS Society is a model of what most disease societies should be. I have been impressed by them from when I entered the research field starting off in MS and being funded – so just for conflict of interest, I was funded at 5M as a post-doctoral fellow – and what I have been impressed because I have had colleagues, I have had neighbors who develop MS or children who have MS, so I’ve seen it from both sides. I am very impressed how they keep a very lean, mean administration, they keep reinvestigating how they should be distributing the money.

 

They think about how much of the money is really going toward patient causes, as things about wheelchairs and thinking about those things, but also in the research; what’s the right time and how much to give the pilots to just generate these, you know, high-risk but potentially high-impact projects and keeping the money small. They look at things for these transition awards to really capture people when they saw that this was a dropout period that people were trying to have a problem launching. They are the ones when you are trying to get that NIH grant and you’ve been a successful investigator, they are focused on MS and they get these nice, shorter three-year grants. And they are very focused. And sometimes if you’re thinking it may be a little too harsh, but saying that it’s MS-focused.

 

So if you are somebody who’s a donor, you should be very happy with the money that you’re giving. And they’re constantly reevaluating the distribution of the dollars, the impact, and, hence, they came up with the Fast Forward. How do they facilitate the problem of pharmaceuticals not bringing enough drugs to therapies, how could they aid this process? Hence, fast forward; trying to bring in nice grants, innovative grants, linking them up with pharmaceuticals to move things forward. So, in a nutshell, they are very milestone oriented not to keep being their own operation alive, but they can’t cure MS to make your life with MS as palliative. You have as much retention of your motor and other capabilities and that you can arrest disease process and perhaps reverse it. So they are very milestone oriented, and I’ve had high respect for how they keep re-self-examining the organization.

 

MSDF

Well, I’ve come to the end of my prepared questions. Is there anything that I haven’t asked about MS research funding that I should have asked, or anything you’d like to add?

 

Dr. Carson

I wouldn’t be afraid of entering the field because of the funding. I think there are multiple ways to have funding. And sometimes you won’t go through the traditional MS societies, sometimes it’ll just be a great idea and you’ll find some other kind of innovative idea. And the last thing I would say that you haven’t asked is that we’re past the time of being the lone-wolf researcher; it really is time to come together, as we have at the symposium here, is taking diverse experts, coming together and melding together projects. These are the ones that are going to be the most competitive in a sense, not only of getting funding, but if we’re really looking at curing diseases, are the most likely to stand the test of time with the diversity of opinions and eyes looking at the problem.

 

MSDF

Dr. Carson, thank you very much.

 

Dr. Carson

Thank you.

 

[transition music]

 

Thank you for listening to Episode Twenty-Nine of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

 

[intro music]

 

Hello, and welcome to Episode Twenty-Eight of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features part two of an interview with Dr. Brenda Banwell in which we discuss pediatric MS. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

Researchers recently put a simple measure of corpus callosum atrophy to the test in a 17-year-long study. The team measured the area of this inter-hemisphere highway in MS patients and found it correlated with their cognitive and physical disabilities over time. Corpus callosum area is faster, easier, and cheaper to measure than volume, since it requires no special equipment beyond the typical MRI machine. The researchers hope they will be able to demonstrate that this measurement can also predict disease course in future studies with larger cohorts.

 

Every Friday we curate research articles on all topics related to multiple sclerosis and highlight our favorites in the “Editors’ Pick.” Two weeks ago, the editors’ picks included a study on the HPV vaccine and MS and another about how cinnamon can ameliorate EAE. Last week we chose a study on heterogeneity among oligodendrocyte precursor cells and another on teasing out the causal variants in genetics association studies. You can see our weekly picks by going to our website, clicking on the “Papers” tab, and selecting “Editors’ Picks.” In addition to the Editors’ Picks, we link to every MS-related study found in PubMed.

 

Our senior science writer, Carol Morton, will be at the Keystone meeting on Neuroinflammation in Diseases of the Central Nervous System in Taos, New Mexico from January 25th through the 30th. She will be on the hunt for good stories and interviews for this podcast, so be sure to say “hi” and tell her all about your latest work.

 

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Now to the interview. Dr. Brenda Banwell is Professor of Neurology and Pediatrics at the Perelman School of Medicine at the University of Pennsylvania and chief of the Division of Neurology at The Children’s Hospital of Philadelphia. Last week, we talked about a new journal called Multiple Sclerosis and Related Disorders, of which she is one of the co-editors-in-chief. This week we turn to her particular subspecialty.

 

[Interview]

 

Interviewer – Dan Keller

I’m here at The Children’s Hospital of Philadelphia with Dr. Banwell, and someone from the public affairs office is here with us. Dr. Banwell, let’s talk about pediatric MS. What are some of the clinical features that you see that may distinguish it from adult?

 

Interviewee – Brenda Banwell

Maybe walk you through a little bit of the journey that the pediatric multiple sclerosis field has taken over the last 10-12 years. When pediatric multiple sclerosis clinics were first being created which was in the late 1990s, the literature on pediatric multiple sclerosis was extremely brief; it was a mixture of patients that we now recognize have multiple sclerosis, some have what we call acute disseminated encephalomyelitis – ADEM – and still others had different demyelinating disorders. And there were no consensus criteria for the diagnosis of multiple sclerosis in children and the criteria for the diagnosis in adults did not include pediatric-onset patients formally. All of that has changed. And in the process of making the diagnosis of multiple sclerosis more clearly, we obviously had to look at the clinical features.

 

So, first of all, I would say that multiple sclerosis onset during childhood and teenage years is relapsing-remitting in character, so clear relapses and periods of clear remission. We have not seen children with primary progressive multiple sclerosis. Worldwide there are a very, very small number of children who may have that diagnosis; it’s extremely unlikely that there are very many, so for all intents and purposes it’s a relapsing-remitting disease during the pediatric age group.

 

The clinical features of attacks are generally very similar to adults with a few caveats. In children who are under about 10, there’s a likelihood that the children will present a little more atypically than adults. The younger children present with an episode with multiple neurological deficits, confusion, even impairment in level of consciousness which can make that first episode very difficult to distinguish from the more traditional acute disseminated encephalomyelitis, the important difference between the two being acute disseminated encephalomyelitis is a monophasic disease, so one attack almost always without any MRI evidence of new disease over time and no further clinical relapses in the vast majority of those children. So it’s a very important diagnosis to distinguish from the lifelong disease, multiple sclerosis, and one can distinguish them obviously on the basis of time but also on certain MRI features. And specifically when one looks at the first presentation, looking for risk determinants for multiple sclerosis are also important.

 

So in that vein, we’ve looked at things that are associated with the likelihood that a first attack is really multiple sclerosis, and those include prior exposure to Epstein-Barr virus, which gives one about a sixfold increased likelihood of having MS; low vitamin D levels which is a problem because low vitamin D levels are quite common in the community now across the board in certain parts of the world, but children who have very low levels are more likely to have multiple sclerosis compared to children whose vitamin D levels were higher when they present with an acute event.

 

If the MRI scan in the brain shows areas of what we call “T1 hypointensity”, which are black holes or really are indications of focal prior brain injury, then those patients are much more likely to have multiple sclerosis. And the reason for that is that in multiple sclerosis, the first attack when you first have the deficits, there’s likely been a period of time behind the scenes where the immune system has begun to attack and has had focal areas of injury that the patient didn’t recognize but are clearly visible on MRI, so MRI is our extraordinarily helpful guide. So areas of abnormality in the brain that are in the what we call periventricular white matter, and then these dark areas on these what are called T1 sequences are strongly indicative that this is a first attack of multiple sclerosis.

 

Conversely, most children with transient illness either have a normal brain MRI and maybe have inflammation in the back of the eye, the optic nerve, or the spinal cord, or they have this ADEM – acute disseminated encephalomyelitis picture – which gives you these hazy, widespread, large, ill-defined changes in the brain MRI that are at least visually quite different from multiple sclerosis. The key subsequent to that is that in patients with multiple sclerosis, by definition there will be new disease over time both on serial MRI scans and clinically. And that is also the case in young adults with relapsing-remitting multiple sclerosis.

 

Genetically, pediatric MS patients do have – at least those from northern European heritage – a higher likelihood of having what we call the HLA-DRB*1501 locus, which is a gene that is important in immune system development or at least immune system recognition of self. And that relationship is true in adult-onset MS as well, and over the last few years the number of genes that have been linked to multiple sclerosis risk overall, and that panel of genes is similar in pediatric-onset MS.

 

So I think the overall message is that relapsing-remitting multiple sclerosis in children and adults is very likely to be the same disease. There are some subtle differences relating to the age of the patient, but if you follow people over time the relapsing-remitting character and the changes on imaging and these clinical feature of kids are really quite similar to relapsing-remitting MS in young adults.

 

MSDF

When you mentioned exposure to Epstein-Barr virus as a risk factor, if you looked at adults about 90% of people have antibody. Do kids generally not have such a proportion of antibody and it’s more indicative there? Does it tell you more if they are positive than in an adult?

 

Dr. Banwell

There’s a lot of evidence that suggests that your multiple sclerosis risk is determined by where you grow up in your childhood years. You may not manifest with the disease until you’re 20 or 30, but all sort of studies, particularly immigration studies, strongly suggest it’s where you grow up that determines your risk. Therefore, if something is a risk factor, one ought to have it if your onset is a 6-year-old or an 8-year-old or a 10-year-old, if it’s important in causing the disease. So when we looked at Epstein-Barr virus exposure in pediatric-onset MS patients, about 80-85% are positive, which compares to only about 35-40% of regional, age, and sex-matched healthy children. So our power to make the relationship is very high. What the Epstein-Barr virus means to the person may be very similar in kids and adults. Certainly in adult-onset MS patients, about 97-98% are positive, which compares to about 90% of the healthy population. So it’s still higher but, of course, you’re sampling the adult patients way past when the exposure may have occurred, and so there’s been time for people who don’t have the disease to also experience the exposure, it just doesn’t matter – presumably – to them; they’re not manifesting with MS.

 

In children, though, when we’re looking at patients who are presenting very, very close to when they presumably had the key risk exposure. So we think that’s biologically important. We’ve also looked at viral shedding. So Epstein-Barr virus is an interesting infection because once you acquire it, it lives in your B-cell population so you have EBV-infected B cells, and about 20% of the year you shed the virus in saliva, which is why it’s so easily spread, particularly in adolescence, which is when it’s particularly acquired. So we looked in our pediatric MS patients at how many times in the course of a year, so with a sample done with most swabs once a month, were they shedding the virus, and looked at Epstein-Barr virus-exposed healthy kids. Healthy children shed the virus 20% of the year, as has been previously reported; MS patients, it was 66-70% of the year.

 

So one of our hypotheses that we’re currently exploring further is whether maybe part of what Epstein-Barr virus might do in MS is, first of all, shed more often so you’re controlling it less well. Every time you shed the virus, your immune system has to turn itself back on and put the virus back into its latent state. If you don’t you can end up with all sorts of complications including lymphoma. And so if part of Epstein-Barr virus’ role in MS is turning the immune system on multiple months per year, that isn’t probably what you want when you have an autoimmune disease; you don’t want your immune system being turned on multiple times a year, particularly if unfortunately you turn on a component of the immune system that may then be directed at the brain. So that’s an interesting phenomenon that we’re currently doing further research on.

 

MSDF

So it sounds like the EBV is something of a polyclonal activator of B cells which then cross-react in the brain, or do react in the brain?

 

Dr. Banwell

Well, that’s the next stage is to see if you look at what immune cells are responding to the challenge of this reactivated EBV, is it that there are specific T-cell clones, and if so are those T-cells specifically looking at proteins expressed both by EBV and by proteins in the central nervous system, sort of a molecular mimicry model, which might be true? Or is it just unfortunate that you’ve turned the whole immune system on, or a large number of aspects of the immune system on, which is more of a general immune process? We don’t know the answer to that.

 

MSDF

Considering these patients start out with relapsing-remitting MS earlier, do they progress to secondary-progressive earlier or at the same age as someone who gets it as an adult?

 

Dr. Banwell

Good question. So the only really good paper on that question, keeping in mind that if we go from prospective studies that are really only started in 1999 to 2000, we don’t have a lot of prospectively rigorously studied pediatric patients. But Dr. Renaud in the New England Journal of Medicine published a paper from the French database where they looked at patients who reported pediatric-onset MS. And what they found was that from first attack until the point at which 50% of their pediatric-onset patients had started into secondary disease progression, that time interval was about 20 years, which is about 10 years longer than one would report on average in adult-onset MS. So if you look at adult-onset MS patients, 50% of them will have entered into secondary disease progression after 10 years from first attack. This is all untreated patients, which of course now is no longer really much the case in developed parts of the world.

 

So the patients with pediatric-onset take longer to start into secondary disease progression, but if you’re only 6 or 7 or 8 when you have your first attack, you’re 28 when you start to develop disability, which is about 10 years younger than most of the adult-onset patients. So the take-home message is it is certainly not more benign based on this particular data, the age at which patients are at-risk of becoming disabled is actually younger, but the time interval from the beginning of their disease until that time point is longer. And we hope that the current therapies and the new emerging therapies will change that outcome, but of course we only are just beginning to have a chance to see that.

 

MSDF

What are some of the challenges in doing clinical trials with a pediatric population?

 

Dr. Banwell

So in adult-onset MS patients, the clinical trial models have been very large; they’ve been randomized, double-blind, placebo-controlled, rigorously done studies that have often employed 200-400 individuals per study arm. And that is often quite feasible because the large MS programs around in North America and in many parts of Europe, an average adult MS clinic where MS is a common can have 3,000 patients alone. There are probably fewer than 3,000 pediatric-onset MS patients available for clinical trials worldwide total, and even that number may be inaccurate. So most pediatric MS programs in the world, of which there are still relatively few that have anything more than five or six patients, are really, really few and far between. So there just simply is a markedly reduced number of pediatric MS patients available for clinical trials.

 

Also challenging the current environment is that there are multiple trials all coming forward at the same time. So the FDA and the European’s Medicine Agency in particular require what they call “Pediatric Investigation Plans” – or PIPs – for all new drugs that are coming to market. In the MS field there are multiple new drugs coming to market. All of them have filed these Pediatric Investigation Plans. So even if we had the number of patients to power one study, we certainly don’t have enough patients to power five or six concurrently, therefore we run the risk of a given trial failing because it doesn’t reach its enrollment numbers.

 

We have families facing choices between multiple potential clinical trials at the same time and centers facing the challenge of launching multiple trials at the same time and the inherent difficulty with all of the work that goes into getting a study up and running at a given center. Pediatric MS patients have never previously been offered pediatric trial opportunities, so the culture of being in a trial is new so it’s a learning curve for everyone. And the medications that are being put forward have varying priorities. So some of the medications are oral, which may be quite appealing to children who are not, understandably, very keen on injections; some are given by infusion and that has varying challenges.

 

A clinical trial is not just an enormous time commitment on the behalf of the patient, in which our case is a child, but also their parents who have work and other commitments and other children. So being part of a clinical trial is an enormous commitment for a family, which is different than the commitment experienced by an individual who’s making that decision on their own behalf. And then adding to all of those challenges is the safety aspects of all these new medications, and of course our top priority amongst anything else is to make sure that our patients stay safe.

 

And so where there may be marked similarity in relapsing-remitting MS as a disease between children and adults, these therapies are being administered at a different time in terms of brain maturation, to a lesser worry but still important in terms of different levels of immune maturation, and certainly – very importantly – at a different stage of life in terms of acquisition of infection. And so many of the new medications that are coming online are more powerful than the medicines that are currently available, many are more capable of suppressing immune responses which puts a significant burden on making sure that everybody is fully vaccinated to the various things we can vaccinate against, but still kids are going to acquire their first infections during the window of time they may be on some of these medications. And so it’s really quite similar to some extent to some of the pediatric oncology care plans that we have to be very, very aware of.

 

MSDF

It looks like the Canadian database of pediatric MS patients is one of the largest; I think when I talked to Amit Bar-Or, it was about 420 or 450. It sounds like there’s a real vying here for patients in terms of clinical trials, and is it even feasible; is it something that you should just discuss with the FDA and say how is this possible to do?

 

Dr. Banwell

So I am one of four members of a clinical trials advisory group on behalf of the International Pediatric Multiple Sclerosis Study Group, which is an international group of about 150 physicians from 40 countries, so I do serve on an advisory to FDA and EMA under that umbrella. And the group of us have very much expressed this concern to FDA and EMA and have articulated our worry about underpowered trials. It’s a difficult environment, there’s a lot of discussion still to be had. The general statement from the regulatory authorities for each of the individual medications that are coming forward is that they are required to have a pediatric plan. And that was a hard-fought battle over many years to try to increase high-quality evidence for treatment of children, which all of us who treat children endorse.

 

So it’s not that we don’t want there to be good trials, it’s just, unfortunately, the reality is that it’s going to be very difficult to do traditional study designs with large arms and placebo-controlled, randomized, double-blinded models are not always going to be suited for all of the therapies. They’re not possible to do for every therapy that’s coming forward, and there’s going to need to be some discussion at a minimum on trial design and potentially on which trials are being done in what order, although that, of course, is certainly not my purview to decide, but it isn’t feasible to run multiple trials in this rare disease at the same time. So we’re going to need to look at rare disease models of therapy that have been put forward for perhaps some of the rare childhood cancers, for example, and other diseases, and we’re going to need the regulatory authorities to recognize we can’t use adult MS study designs for pediatric MS patients.

 

MSDF

Very good, I appreciate it. Thank you.

 

Dr. Banwell

Oh, you’re welcome.

 

[transition music]

 

Thank you for listening to Episode Twenty-Eight of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

 

[intro music]

 

Hello, and welcome to Episode Twenty-Seven of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Dr. Brenda Banwell about a new journal on multiple sclerosis and related disorders, of which she is a co-editor-in-chief. But to begin, here’s a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

This week we published two stories related to articles published in the December 2014 issue of JAMA Neurology. The first article is about the interim results of the Halt MS trial. In this phase 2 clinical trial, physicians performed autologous hematopoietic stem cell transplants on 24 patients with relapsing-remitting MS. In other words, the team obliterated the patients’ existing immune systems and attempted to hit the reset button by infusing the patients’ own stem cells. Three years after the treatment, 78% of patients showed no signs of disease activity, significantly higher than similar studies using conventional MS treatments. However, not everyone is popping the champagne yet. Some are concerned that the treatment may not have been aggressive enough to eradicate the patients’ entire immune systems, and it will be only a matter of time before some patients start showing signs of disease activity once more. Others are concerned that the treatment was unnecessarily intense and risky, suggesting safer methods of stem cell transplant would be effective in resetting the immune system.

 

Halt MS is one of the trials using a new primary outcome measure called “no evidence of disease activity” or NEDA for short. NEDA is basically a fancy way of saying “remission”; that is, no relapses, no disability progression, and no new lesions on MRI. NEDA sets a new treatment standard for patients and their doctors, reflecting the hope of a new generation of disease-modifying therapies.

 

But is NEDA really a feasible clinical care target? Our second story this week takes a look at this issue with the first real-world cohort study. Researchers asked how many people with relapsing-remitting MS maintained NEDA status seven years after diagnosis. While that goal remained elusive for all but 8% of patients, NEDA status at two years was highly predictive of no disease progression at seven years. Many questions remain about NEDA. But in an editorial accompanying the study, researchers suggest that NEDA is still a worthy, albeit very ambitious, goal.

 

What do you think? Let us know on the discussion forums at msdiscovery.org/forums/discussion.

 

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Now to the interview. Dr. Brenda Banwell is Professor of Neurology and Pediatrics at the Perelman School of Medicine of the University of Pennsylvania and is chief of the Division of Neurology at The Children’s Hospital of Philadelphia. We met to talk about a fairly new journal called Multiple Sclerosis and Related Disorders, of which she is one of the co-editors-in-chief.

 

[Interview]

 

Interviewer – Dan Keller

I’m here at The Children’s Hospital of Philadelphia with Dr. Banwell, and someone from the public affairs office is here with us. I’m just wondering why did you see a need for a new journal?

 

Interviewee – Brenda Banwell

At the time that we launched Multiple Sclerosis and Related Disorders, there were journals focused solely on multiple sclerosis and journals on neurology broadly, but not one that focused specifically on multiple sclerosis and the various and increasing number of demyelinating disorders of the central nervous system that are being recognized. So Multiple Sclerosis and Related Disorders was meant to be a home for sometimes comparisons, sometimes new insights, and certainly thoughtful reflection on the scope and breadth of demyelinating disorders in the central nervous system in adults and in children.

 

MSDF

Is there a certain amount of waiting, or it’s just the volume of papers that you get in that determines the mix between multiple sclerosis and other demyelinating disorders?

 

Dr. Banwell

Really it’s actually the quality of the papers we receive that drive the selection into the journal. To date, we have been blessed to receive some very interesting manuscripts, some of which relate to multiple sclerosis but many others relate to neuromyelitis optica, which is one of the disorders we were interested in; in antibody-associated encephalopathies; in patient perceptions of demyelinating disease, which is from the area that I think is very interesting and relevant; and then even some basic science, manuscripts that have looked at mechanisms of the immune system targeting the central nervous system.

 

MSDF

Is there a particular editorial philosophy?

 

Dr. Banwell

I guess the one my co-editors and I would say that we’re looking for manuscripts that push the envelope a little bit in terms of hypothesis generation. We like to see a thoughtful reflection on where the next step needs to be in the papers that we accept. And we’re not at all uncomfortable with being a little bit provocative in terms of perhaps people broaching new hypotheses as long as those hypotheses are well defended and can generate the next step of research.

 

MSDF

So it sounds like you’re also delving into basic science, or at least early clinical studies here, too?

 

Dr. Banwell

We’ll delve into it. We are not a basic science journal, so we would not pretend to be Cell or Nature or any of those sorts of journals. But certainly many of the manuscripts that we’ve accepted have discussed potential hypotheses based on basic science research and how that might tie to the clinical picture.

 

MSDF

One question that always arises with a new journal is why should people want to publish in this journal as opposed to some of the more established ones?

 

Dr. Banwell

Well, I think like any new journal, we have a lot of opportunity to accept manuscripts. We have very quickly gotten to the point where we have a very high caliber of manuscripts, which I think speaks to the interest in the field, so the journals that are arguably in competition with us are also now increasingly receiving high quality manuscripts as well. And I think overall it reminds us that there is actually quite a bit of research going on in multiple sclerosis and related disorders, and therefore there’s room for several journals in the field at this time.

 

MSDF

Is it now being indexed in PubMed?

 

Dr. Banwell

We have applied for indexing and we’ll hope to hear very shortly.

 

MSDF

Is there any problem or have you faced any barriers?

 

Dr. Banwell

No barriers. It’s just that you have to have a certain number of manuscripts published, you have to show that the manuscripts are of high quality, and you have to have been in the field long enough to actually have enough publications for them to judge the quality of what we’re doing.

 

MSDF

I see that you have co-editors-in-chief. Who are your colleagues in this?

 

Dr. Banwell

So there’s Dr. Chris Hawkes and Dr. Gavin Giovannoni from England, and Dr. Fred Lublin from the United States.

 

MSDF

Anything else important to add about the new journal or the things that it’s come out with lately?

 

Dr. Banwell

Well, we have a lay review author as well, and we do hope to increase some scholarly input from the lay public over time. Certainly we’re interested in maintaining the sort of price we put on novelty and in encouraging people to submit work that is perhaps looking at a new angle in the field. I think the related disorders aspect of our journal is an important component, both of the title and also of the concept. We are particularly interested in some of the emerging disorders that we now realize are potentially, if not multiple sclerosis, certainly in the field of immune-directed responses in the central nervous system. So I think that aspect of our journal speaks to an area of the field that might not have been previously quite so well captured in the existing journals.

 

MSDF

Does this journal lend itself to a more global approach to demyelinating diseases, since it’s multiple sclerosis and related disorders as opposed to just looking at MS as an isolated condition?

 

Dr. Banwell

Certainly in concept, yes. I think in fairness to the other journals that I think are all excellent and also in the field, we are not the only ones that are broadening the scope. And I think that speaks to the discoveries. So with the identification in 2004 of the aquaporin-4 antibody, and then subsequent to that really compelling evidence that the aquaporin-4 neuromyelitis optica story broadened and recognized a very specific subgroup of patients, that is also happening with other antibodies potentially, and there’s some emerging information about, for example, NMDA receptor encephalitis and other disorders that weren’t really recognized as such a few years ago. Our journal is prioritizing this type of sort of patient base and diagnostic categories, but so too are other journals that are also excellent in the field. So I think in fairness, everyone is recognizing that there’s more to the story.

 

MSDF

Is the NMDA antibody story with the catatonia?

 

Dr. Banwell

So NMDA receptor encephalitis is a disorder actually discovered by Josep Dalmau at Penn, so very near and dear to our heart here. The patients present sometimes with psychotic features, they can become quite catatonic. There’s been some lay publications on that. “Brain on Fire” was a book written by a survivor of NMDA receptor encephalitis. In children we certainly see – and in adults, but certainly in children – we see a number of patients present with severe seizures and then with abnormalities of movement. When these patients present they can be catastrophically ill, often in intensive care unit. Over time as the patients recover, miraculously it seems because it really does appear to be quite miraculous, the patients can have a full recovery. So it is a disorder that’s extremely important to recognize and can be misdiagnosed quite easily as an infectious encephalitis, as initially other psychiatric disorders, and in some patients as a really severe form of epilepsy, all of which it is, but it has a better overarching diagnosis. And making the diagnosis certainly gives hope in terms of long-term prognosis, and we do use specific therapies for the patients with the diagnosis.

 

MSDF

Very good, I appreciate it. Thanks.

 

Dr. Banwell

My pleasure.

 

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Thank you for listening to Episode Twenty-Seven of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

 [outro music]

 

[intro music]

 

Host – Dan Keller

Hello, happy new year, and welcome to Episode Twenty-Six of Multiple Sclerosis Discovery, the podcast of the MS Discovery Forum. I’m your host, Dan Keller.

 

This week’s podcast features an interview with Tim Kennedy about remyelination and neural development. But to begin, here is a brief summary of some of the latest developments on the MS Discovery Forum at msdiscovery.org.

 

According to a new clinical trial, azathioprine, or AZA, may be as effective as interferon beta. The generic immunosuppressant was effective in both reducing relapses and reducing new brain lesions in the multicenter trial. This may not be surprising since the drug has been used off-label to treat MS for several decades. If trials continue to go well, AZA may become the go-to alternative for patients who can’t afford brand name interferons.

 

A pair of Canadian studies recently showed that both neurodegeneration and inflammation may start in the early stages of pediatric multiple sclerosis. One team found epitope spreading in the blood of children shortly after the onset of MS, suggesting a potential new diagnostic tool. Though children comprise only 2 to 10 percent of the MS population, data gleaned from them may provide insights into the disease as a whole.

 

If you enjoyed our end-of-the-year interview with Alan Alda and find MSDF to be helpful, please consider supporting us with a donation. We share Mr. Alda’s philosophy that closing the gaps between scientific disciplines is key to improving scientific progress. To make a donation, visit msdiscovery.org and click on the green “Support MSDF” button next to “Research Resources”.

 

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Now to the interview. Tim Kennedy is a researcher at the Montreal Neurological Institute. He met with MSDF to talk about the role of certain molecules and receptors necessary for oligodendrocyte development, maintenance, and function and their implications for remyelination.

 

Interviewer – Dan Keller

Welcome, Dr. Kennedy. Let's talk about the life of oligodendrocytes. These are important for myelination and probably play a role in remyelination. What is the life of an oligodendrocyte? How does it start out? And what does it react to?

 

Interviewee – Tim Kennedy

Many labs around the world have been studying the life history of an oligodendrocyte and also the lineage of the cells and how they differentiate during normal development. One of the reasons for doing this is that oligodendrocyte precursor cells are present in the mature nervous system and almost certainly contribute to remyelination in demyelinating diseases like MS. Oligodendrocyte precursors are born in the early embryonic CNS, and from the very restricted regions where they're born they then migrate away to populate all of the regions of the mature CNS where myelin occurs. In the lab here, we've been very interested in the molecular cues that direct and influence oligodendrocyte precursor migration. These include a family of proteins called netrins that we work on. And receptors for netrin like a protein called DCC. DCC stands for deleted in colorectal cancer. It was originally identified in cancer, and we now know that it has a critical role in the central nervous system in the migration, maturation, and maintenance of myelin by mature oligodendrocytes.

 

MSDF

Some of these molecules take on different functions as the oligodendrocytes mature. How do they react, or what do these molecules do over time?

 

Dr. Kennedy

When an oligodendrocyte precursor is born, it makes the netrin receptor DCC, but it doesn't make netrin. What the cell does is it responds to netrin in the environment, and through DCC reacts to it, and the netrin directs the cells to migrate. It tells them to initially migrate away from the position where they're born and sends them in the direction of axon tracks that require myelination. In mature myelinating oligodendrocytes, one of the huge surprises we had is that both of these proteins are made. Now, both netrin and DCC are required for normal neural development. If we examine a conventional knockout mouse that lacks either netrin-1 or DCC, those mice die within a few hours of being born, and there's a massive disorganization of the nervous system. So these are essential for normal neural development. When we look at the mature nervous system, we see that every single oligodendrocyte, every single mature myelination oligodendrocyte, makes readily detectable levels of netrin-1 and also the receptor for netrin-1, DCC. And a very simple statement of the question that we wanted to answer is what's the point of that? Why do these cells make these proteins that are essential for normal neural development but make them in the adult nervous system? In every adult human that we encounter, every single person, we're making netrin-1 and DCC in our brains right now. So what's the point? One of the functions that we've recently identified is that DCC produced by oligodendrocytes is required for the maintenance of myelin. Now what that means is that initially when we looked at the distribution of netrin-1 and DCC in relation to myelin we see that they're enriched at paranodal junctions. Paranodes are at the ends of internodes that are the regions of compact myelin that wrap and insulate an axon. The paranodes are a specialization that's made by the oligo that then connects it and ties it down to the surface of the axon. The paranodes flank the node of Ranvier, which is the key point, the specialized region along an axon that regenerates the action potential. So if we think of the internode of compact myelin as the region where the oligodendrocyte insulates the axon and allows the action potential to jump from node to node, the paranodes are the specializations at the end that tie it down. Now, the paranode is where we see the netrin and DCC enriched. If we take away either netrin-1 or DCC from oligodendrocytes, what we see is that the paranodes begin to come apart. Now in a very recent publication, what we did was use a genetic trick called cre-lox recombination to selectively take DCC out of mature myelinating oligodendrocytes. In these mice, the mice develop perfectly normally, the nervous system develops normally, the myelin develops normally. But then, at two months of age, we induce the deletion of DCC only from oligodendrocytes. Now having taken DCC out of oligodendrocytes, what we see is that first the paranodal junctions start to come apart, and then as we let the mice age the compact myelin itself starts to become disorganized. Now, that's interesting because what we're able to document in these mice is a progressive disorganization of the myelin produced by the oligodendrocyte. The progression is interesting, obviously, because we believe that this has identified a new mechanism that maintains myelin, and we would then relate that to the progression of demyelinating disorders like multiple sclerosis. A consequence of having lost DCC is that the action potential conduction velocity in the nervous system is delayed, and when we look at the mice themselves – and look at their behavior, put them through behavioral tests – what we see is that they become uncoordinated and slower in their movements. So again, this would all be consistent with this disruption of the myelin along the axons in the central nervous system due to the loss of DCC. And it's an indication that DCC being made by oligodendrocytes is absolutely essential to maintain the appropriate organization of myelin.

 

MSDF

That explains why myelin may become disorganized. Now, if there is a state in which it's already disorganized, which we look at someone with MS, is there any indication here how to remyelinate knowing what you now know about what's required for maintenance of myelin?

 

Dr. Kennedy

Certainly. What's really exciting having found that DCC is essential to maintain myelin is that this is a new biochemical mechanism that is required to organize and maintain the structural paranodal junctions, and that that's critical for the integrity and the maintenance of compact myelin. Now, DCC is a transmembrane receptor, and every single component of the signal transduction pathway downstream of DCC is potentially a drug target that could be manipulated to enhance the maintenance of myelin. So this is a new biochemical mechanism that exists in oligodendrocytes that promotes myelin maintenance. And that has enormous potential for trying to encourage the persistence of myelin in demyelinating disease.

 

MSDF

What about remyelination? I think you've said oligodendrocytes are born to myelinate. What's stopping them?

 

Dr. Kennedy

If we go back to the oligodendrocyte precursor in early development, what our studies of the developing nervous demonstrated was that oligodendrocyte precursors are repelled by netrin-1. The normal function of netrin-1 in the early embryo is to drive oligodendrocyte precursors away from where they're born so that they can go out into the rest of the central nervous system, find axons that need to be myelinated and myelinate them. That indicates that in the early embryo netrin-1 is a repellent for these cells. Again, we recently reported that in human MS plaques netrin-1 is present in those plaques. Where that's likely coming from is from the wreckage of cells that have died in those plaques. So I had said that mature myelinating oligodendrocytes express netrin-1. When those cells die and when the myelin is lost, the debris from those cells remains behind and potentially even builds up in plaques. There are a number of inhibitors of oligodendrocyte precursor migration that we now know are present in human MS plaques. These include proteins like chondroitin sulfate proteoglycans, semaphorins, and now netrin. What that strongly suggests is that when oligodendrocyte precursors are migrating in the adult brain to sites of demyelination with the intention of remyelinating an axon that has been demyelinated these inhibitors will very likely prevent those cells from entering the plaque and doing what they were born to do, which is to remyelinate. A very exciting thing about MS research today is that we know that the brain contains stem cells that produce oligodendrocyte precursor cells that readily give birth to these cells. So all of us have oligodendrocyte precursor cells in our head. Those cells are born to myelinate. They will migrate towards plaques where demyelination has happened, and if they're allowed to enter the plaque find the axon that needs to be remyelinated. And if they can be encouraged to overcome whatever it is that is blocking them from remyelinating, potentially that aspect of MS remyelination could be encouraged to happen.

 

MSDF

Do you have some ideas on how to overcome this blockage either clearing away the debris or making the oligodendrocytes insensitive to the inhibitors and the debris?

 

Dr. Kennedy
Both of those approaches would be very appropriate. So encouraging the nervous system to clear away the debris we would predict that that would encourage remyelination to happen. In addition, although I said there were multiple inhibitors present in MS plaques – and those inhibitors have different receptors – downstream of those receptors it's very likely that common signal transduction mechanisms are engaged. So targeting those common signal transduction mechanisms inside the migrating oligodendrocyte precursor cell could very potentially nullify all of the inhibitors at once. If it was possible to turn off the sensitivity to those inhibitors, then we would predict that the cells would enter the plaque more readily, and more of the cells would then be able to encounter the axons that require remyelination, and we would obviously predict that that would promote remyelination happening.

 

MSDF

What are some of the big questions now to look at, solve?

 

Dr. Kennedy

The oligodendrocyte is an absolutely fascinating cell type. It's a highly specialized cell type, critically clinically important. We still understand very little about these cells. The mechanisms that I've been talking about that regulate the maintenance of myelin, those have only very recently been discovered. And I think it's extremely exciting that this type of thing is being found in oligodendrocytes. But these are still very mysterious cell types. I think the more we understand about the cell biology of the oligo the more we'll be able to target pathways in the biochemistry of oligodendrocytes to try and promote things like myelin maintenance and the ability to remyelinate. Being able to do those things and essentially manipulate these cells in specific ways, we can then overcome specific clinical issues.

 

MSDF

Does this go beyond MS? Are there other conditions that it applies to?

 

Dr. Kennedy

I think there are two things built into that question. One is that there are many diseases for which the cause either isn't clear – and MS would be in that category – or there are also diseases that have many different causes, but they may manifest in similar ways. So by understanding oligodendrocytes and being able to encourage oligodendrocytes to remyelinate, that could have broad applicability for treating the symptoms of many different forms of demyelinating disease irrespective of the cause of those diseases. Beyond that, as we come to better understand how cells move in the nervous system, how they migrate, how they form attachments, how they connect to each other, and how they maintain those connections, those kinds of insights are going to have broad applicability for all sorts of neurodegenerative diseases where the basic problem in the neurodegenerative disease is that the networks that are the nervous system are coming apart. And if we can encourage those networks to just stay together or rebuild themselves, then I think that again has broad applicability to many types of neurodegenerative diseases in the myelinating field and outside of myelination, as well.

 

MSDF

It sounds like it may even have applicability to not only neurodegeneration but in development where you may have miswiring such as potentially an autism or something like that.

 

Dr. Kennedy

Yeah. An exciting thing is that a lot of the mechanisms that I'm thinking about and we're thinking about in the lab is that the insights that got us working on myelin, that brought us to work on myelin really came from neural development and better understanding neural development; the studies of neural development identified proteins and gene families that have very, very potent actions in the nervous system. When we then looked at expression, we saw that they were expressed in the mature CNS, and that brought forth a whole other group of questions related to the function of the normal adult nervous system and also the degeneration of the adult nervous system in neurodegenerative disease. The exciting thing about that is that as we understand the molecular biology of the central nervous system better that's going to be applicable to development, to normal function, to enhanced function, and also promoting function in degenerative conditions.

 

MSDF

I appreciate it. Thank you.

 

Dr. Kennedy

You're very welcome.

 

[transition music]

 

Thank you for listening to Episode Twenty-Five of Multiple Sclerosis Discovery. This podcast was produced by the MS Discovery Forum, MSDF, the premier source of independent news and information on MS research. MSDF’s executive editor is Robert Finn. Msdiscovery.org is part of the non-profit Accelerated Cure Project for Multiple Sclerosis. Robert McBurney is our President and CEO, and Hollie Schmidt is vice president of scientific operations.

 

Msdiscovery.org aims to focus attention on what is known and not yet known about the causes of MS and related conditions, their pathological mechanisms, and potential ways to intervene. By communicating this information in a way that builds bridges among different disciplines, we hope to open new routes toward significant clinical advances.

 

We’re interested in your opinions. Please join the discussion on one of our online forums or send comments, criticisms, and suggestions to editor@msdiscovery.org.

 

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