Podcast – Neuroinflammation drug discovery in stem cell-derived microglia

Voice Over:

Welcome to the NIHR Dementia Researcher Podcast, brought to you by dementiaresearcher.nihr.ac.uk, in association with Alzheimer’s Research UK, and Alzheimer’s Society. Supporting early career dementia researchers across the world.

Megan Calvert-O’Hare:

Hello, and welcome to another podcast brought to by NIHR Dementia Researcher. I am Meghan O’Hare, and today I’m going to be talking with three researchers from Oxford University. We are going to explore why microglia are awesome, why they use induced pluripotent stem cell models, and how they feed genome-wide association studies, hits, and basic science into drug discovery, with phenotypic screening.

Megan Calvert-O’Hare:

Before we start, I just want to explain that this is during the lockdown, so we are recording this all at a very safe distance away from each other, on laptops. The sound quality won’t be quite as good as when we’re in the studio, but the quality of the conversation will be good, so that’s fine.

Megan Calvert-O’Hare:

I’d like to introduce Dr. Hazel Hall-Roberts, who is a black-belt in Wado-Rye … is that how you say it?

Dr Hazel Hall-Roberts:

It’s Wado-Ryu. And it’s not how it’s spelt, yes.

Megan Calvert-O’Hare:

And postdoctoral research scientist at the Sir William Dunn School of Pathology, and ARUK Oxford Drug Discovery Institute. Dr. Emma Mead, a senior neuro-biologist and team leader at the ARUK Oxford Drug Discovery Institute. Who also has an allotment and is very creative in the kitchen, both skills that I think are coming in handy during this isolation time?

Dr Emma Mead:

Yeah, absolutely. Keeping me busy.

Megan Calvert-O’Hare:

And Maria Kreger Karabova. How did I do?

Maria Kreger Karabova:

Very well. Better than most people.

Megan Calvert-O’Hare:

Okay! DPhil student, also at Sir William Dunn School of Pathology, University of Oxford. And Maria’s claim to fame is that she once overheard squatted her postdoc supervisor. Did you drop them?

Maria Kreger Karabova:

I did not. No postdocs were harmed that day!

Megan Calvert-O’Hare:

Okay, great.

Megan Calvert-O’Hare:

So, hello everyone.

All:

Hello.

Megan Calvert-O’Hare:

Thank you for joining us. So let’s start with all of you to introduce yourselves better than I’ve just done, and tell us a bit more about your background and how you came to be at Oxford. Shall we start with Hazel?

Dr Hazel Hall-Roberts:

Hi, I’m Hazel, obviously. So this is my first postdoc, and before this I did my PhD at the University of Bath, which was doing dementia research using immortalised cell lines. And at the end of that period of time, I thought, I really want to work on stem cells, but wanted to stay in dementia, so I came to Oxford to learn about stem cells and work in one of the best stem cell facilities in the whole country, with Dr. Sally Cowley and Professor William James. And this has the added bonus of also getting to work with the ARUK Drug Discovery Institute, who fund me.

Megan Calvert-O’Hare:

Great. Before we move on to the other two, just quickly, why did you want to carry on working in stem cells?

Dr Hazel Hall-Roberts:

I wanted to learn about stem cells because, at the time, it felt like there was this dichotomy of people working on in vivo models and people working with stem cells, and there wasn’t much of a future for just doing bog standard cell line work. And I’m a bit squeamish, so that’s the honest truth.

Megan Calvert-O’Hare:

Okay. So no mice are harmed by you? Okay!

Megan Calvert-O’Hare:

And Emma?

Dr Emma Mead:

Yeah. So I undertook a degree at the University of Glasgow in Molecular and Cellular Biology. And then I moved on to do a PhD in Neuroinflammation. And I’ve always been really interested in translational research, so my postdoc was more angled towards looking at how anti-inflammatory compounds could be taken into the clinic. And from that I went industry and joined Eli Lily, where I worked to develop inflammatory and neuroimmune platforms.

Dr Emma Mead:

There was really a point where I felt like I wanted to be more involved in directing research and having my own group, and there was a really great opportunity that came up at the University of Oxford at the Drug Discovery Institute, to be able to grow into that area. I was really pleased that they were happy to take me on as a group leader.

Megan Calvert-O’Hare:

That’s great. My undergrad degree was also in Molecular and Cellular Biology, and every time I tell people, they’re, like, “What?”, because I just ramble it all together to get it over and done with.

Megan Calvert-O’Hare:

Okay. And Maria?

Maria Kreger Karabova:

Hi. At the moment I’m a second year DPhil student. I’m a neuroscientist by training. I completed my degree at King’s College London, in 2018. To be very honest, I’m still in a little bit of an awe from how I ended up in Oxford. During my undergrad, I was fortunate to participate in a study abroad program. This is something I completed at the MIND Institute at the University of California in Irvine. I first dipped my toes into Alzheimer’s research then. I received a fantastic mentorship from one of the pioneers in the field of synaptic plasticity, and I also devoted my time volunteering at low income clinics, so I was able to see the effects of dementia on patients and carers first hand.

Maria Kreger Karabova:

I knew when I returned to the UK I really wanted to pursue the dementia research. I literally Googled Alzheimer’s Research UK, in hope of finding laboratories where I could carry on with internships. I half expected my emails to end up in spam, but you can imagine my surprise when I few weeks later I heard back from the Oxford Drug Discovery Institute and Dunn School of Pathology offering me a joint summer internship. Hazel was actually one of my supervisors. There was really a no point of return for me, because the environment, the facility, the novel stem cell methods I was exposed to, and the mentorship, it just sealed the deal and it really encouraged me to continue with dementia research, and file a PhD application. And here I am.

Megan Calvert-O’Hare:

Great! Do you all work in the same area, same lab now, is that correct? Or, maybe, Hazel?

Dr Hazel Hall-Roberts:

How we fit together is that Maria and I work in the same lab at the Dunn School of Pathology, and with William James and Sally Cowley. But I also work with Emma Mead, who’s based “up the hill” from us, as we say, up in the Old Road Campus. And she’s got her own neuroinflammation team, and I’m also part of her team, with a number of colleagues working on similar things.

Maria Kreger Karabova:

And also, Emma has been incredibly helpful to my project, helping me with the purification of the protein of interest.

Megan Calvert-O’Hare:

Maybe, you could take us through that a little bit?

Maria Kreger Karabova:

Yeah. I can kick-off. So my primary research interest lies in the role of neuroinflammation in the pathogenesis of Alzheimer’s disease. And we’ve known in our field that neuroinflammation is a common denominator in the neurodegeneration for quite some time, following the GWAS hits and also imaging studies. But, the reactive microgliosis, the pro-inflammatory state of microglia around toxic protein aggregates in neurodegeneration, it has been consistently described in multiple neurodegenerative diseases but it was always thought to be secondary to the actual neurodegeneration processes. The molecular processes surrounding the phagocytic uptake, degradation and secretion of the protein deposits in microglia, particularly in humans, are still very poorly understood. This is what I’m currently working on.

Maria Kreger Karabova:

I’m studying the molecular processing of tau protein aggregate. That means my protein of interest by human iPS-derived macrophages and microglia.

Megan Calvert-O’Hare:

Okay, so, you’re using induced pluripotent stem cells.

Maria Kreger Karabova:

Yes.

Megan Calvert-O’Hare:

Right?

Maria Kreger Karabova:

Yes.

Megan Calvert-O’Hare:

Okay. They are, just, some of our listeners are social scientists, some work in health and social care, some are bench scientists. Maybe you could talk through actually what induced pluripotent stem cells are for us, just very quickly.

Maria Kreger Karabova:

Induced pluripotent stem cells are a fantastic tool when you want to move on beyond cell lines, which are immortalised cancer lines but don’t technically reproduce the physiology of the actual cells in human body. Induced pluripotent stem cells are cells that had been basically, to start off, they were your fibroblasts, your skin cells that are then induced by a special cocktail of transcription factors back to their proliferatory properties, your stem cell properties, when all the cells are capable of differentiating to everything in your body, so all the other cells in your body. Then, from this fate, when they’re in their stem cell fate, we can use a set of different transcription factors and differentiation factors to push them into whatever fate we want them to take on. We can take these stem cells and push them onto become neurons, which we can work with, or microglia, or epithelial cells, and stuff like that.

Maria Kreger Karabova:

They have a wonderful advantage of reproducing the authentic human physiology recapitulating that, but in a dish where we can zoom in and get rid of all the systemic noise and all the other variables.

Megan Calvert-O’Hare:

Okay. I actually didn’t realize you started with a cell line. I thought you started with stem cells. That’s interesting. So, you take them back to the stem cell situation.

Maria Kreger Karabova:

You would start with skin cells, which are taken by biopsy and these are then reprogrammed to stem cell lines, which we store in freezers, and then conveniently we can thaw them whenever needed.

Megan Calvert-O’Hare:

Okay. So, you’re starting to build up a big library of stem cells and then you can push them into the cell fate that you want them to have. Like you said, neurons or microglia.

Megan Calvert-O’Hare:

Once you have them like that, obviously, in the neuroinflammation paradigm you’re working with, they are activated microglia, is that right? So, you can still activate the microglia?

Maria Kreger Karabova:

Activated microglia is a little bit of an interesting phrase because we’re learning about what microglia respond to, how they behave and when they’re activated. Perhaps the activation doesn’t have anything to do with a specific insult but perhaps their surveying, patrolling role. When we culture the microglia in a dish, we’re still not 100% sure whether they’re activated at that point or whether they take on the activated role only upon an insult, perhaps by feeding them with a cargo they would normally be phagocytosing, such as, E. Coli, zymosan, or, in the context of neurodegeneration your proteins of interest.

Maria Kreger Karabova:

The whole question of whether and when microglia are activated, there is a lot of discussion going on about that being on a spectrum. So, they can interchangeably transcribe a set of genes to plastically change their behaviour depending on what kind of environment they are in.

Megan Calvert-O’Hare:

Okay, and in your dish with your microglia, do you have neurons as well? So, you have more of a mixed environment of cells?

Maria Kreger Karabova:

I personally don’t. At the moment I’m working with iPS-macrophages and microglia only but our lab, specifically postdoc, Walther Haenseler, has developed a co-culture system in which, when we culture neurons with the iPS-macrophages, interestingly, the iPS-macrophages actually take on the more microglia-like characteristics. This really goes on to show that it’s the systemic talk between several types of cells that pushes them towards their true fate.

Megan Calvert-O’Hare:

Emma, maybe we could hear from you a little bit about how you link with Maria’s work, how Maria links with you, and also your own independent work?

Dr Emma Mead:

Yeah, sure. I work pretty much entirely in the drug discovery space. At the ODDI we’re interest in taking hits from GWAS studies and looking at whether they could become tractable targets. We do lots of target validation, so investigating whether something is likely to be involved in Alzheimer’s disease or other dementias and taking it forward to see whether we can develop screening assays to target that protein of interest and modulate it in certain ways.

Dr Emma Mead:

In the context of the work that we do with Hazel and Maria, Hazel works on one of our key projects and she’s involved in the target validation side of that and developing some nice assays to investigate that further.

Dr Emma Mead:

With Maria, a couple of my team members are protein biochemists, and they’ve been developing methods to produce tau proteins, so the proteins aggregated in Alzheimer’s disease, and it plays an important role in causing a number of pathologies that we see in dementia. My group have been providing Maria with some tau and helping her, and teaching her how to make it herself.

Dr Emma Mead:

That’s where I fit in with both Hazel and Maria.

Megan Calvert-O’Hare:

Okay. We had a podcast last year. I think it was called “Fifty shades of microglia”. Hopefully our listeners will listen to that, so they know the general role of microglia but maybe we could hear from you Maria about quite how awesome microglia are?

Maria Kreger Karabova:

Sure. In my personal experience, I always think of microglia as your very own personal ninjas, avenging any kind of threat to your brain and all of the central nervous system. In more scientific terms, microglia serve as your phagocytic sentinels, so the key effector cells of the immune system patrolling the brain, maintaining homeostasis, making sure that everything works just fine, pruning any unnecessary connections and also clearing up pathogens and cellular debris. They’re not just smart and capable, they’re quite the looker because they’re really fascinating to observe and study under a microscope.

Maria Kreger Karabova:

For me personally, what I really appreciate about microglia is that their function and dysfunction in the brain represents uncharted territory, secrets behind open doors, if you will, because it really stirs hope for new discoveries and treatments. The brain has been studied for decades from that cup. It was almost always as if the brain functions doesn’t function in unison with the periphery and other cell types surrounding neurons.

Maria Kreger Karabova:

The term glia literally derives from Greek “glue”, reflective of how the microglia very long thought of and basically it was just a support to the main star of the game, the neurons. For me personally, as a neuroscientist, it’s really encouraging and exciting to see the growth of the inter-disciplinary approach, and the efforts to understand neuronal function in the context of everything else that’s going on in the brain.

Megan Calvert-O’Hare:

So, microglia eat up amyloid and tau protein tangles through phagocytosis. Do we just want them to do more of that?

Maria Kreger Karabova:

I personally actually believe that we shouldn’t be focusing therapeutically on boosting the phagocytic ability before we understand better what’s happening following the phagocytosis. At the moment it is thought that the decrease in phagocytic clearance of the misfolded proteins in the AD is what’s contributing to the pathogenesis. But effective clearance actually relies heavily on the ability to then degrade the cargo via endo-lysosomal pathways. Endosomal trafficking and lysosomal abnormalities preceded the appearance of the protein deposits some 20 years prior to the diagnosis. There is plenty of GWAS hits highlighting the lysosomal dysfunction in AD and it’s this long-standing, forgotten hypothesis that should be perhaps revisited again.

Maria Kreger Karabova:

Just boosting the phagocytic ability of microglia can be downright detrimental and inducing a situation where lysosomes can rupture, and all the cargo can be then released into the extracellular matrix from which it can propagate and cause further havoc.

Megan Calvert-O’Hare:

That’s lysosome dysfunction within microglia or do you mean in neurons as well throughout the brain?

Maria Kreger Karabova:

I was referring specifically to the lysosomal function in the microglia although there is a lysosomal dysfunction documented also in neurons in the context of AD. But focusing on increasing phagocytosis before we know whether this can be degraded could be detrimental, in my opinion.

Megan Calvert-O’Hare:

But the lysosome dysfunction in neurons, I assume, happens also 20 years previous to the amyloid, if it’s also happening in microglia, is that right, or no?

Maria Kreger Karabova:

Yeah, that’s correct. So far, we don’t really have very tangible evidence of that because, as you can imagine, it’s difficult to visualise it 20 years prior to the diagnosis because you can’t take a set of people predicting whether they will go on to develop Alzheimer’s disease 20 years onwards, or not. We don’t understand the molecular processes before the diagnosis but that is the general effort, trying to understand exactly what’s going on and to catch the disease earlier.

Megan Calvert-O’Hare:

Hazel, you mentioned that you work with induced pluripotent stem cells, which you gave us a really nice description of but maybe we could actually talk about the advantages of using some of them.

Dr Hazel Hall-Roberts:

Oh, great. Generally, we’re using cells derived from iPSCs as an alternative to using primary rodent cells in order to isolate a particular cell type and study that. One really important advantage relative to rodents is that there are some differences between human and rodent genes, particularly with microglia-specific genes. In fact, there are some microglial genes in humans that are not expressed at all in mice. My particular gene of interest, TREM2, is expressed in mice but, as well as simply low orthology- there are quite a lot of dissimilarities in the primary amino-acid sequence with the rodent gene- there was a fairly recent study showing that, if you insert an Alzheimer’s disease risk mutation into TREM2 in the mouse gene, called R47H, it leads to the formation of a premature stop codon and aberrant splicing and, in fact, TREM2 ends up not being expressed. Whereas, if you do that to the human gene, the TREM2 protein is expressed perfectly normally and spliced correctly. We feel that this emphasises the importance of knowing- with what you’re studying, the particular focus that you have- that you are looking at the right gene that, if it’s quite different in the mouse, then you really ought to be using the human model.

Dr Hazel Hall-Roberts:

There are a few other advantages. With the iPSC lines that we have, we can gene-edit those and turn them into a number of different cell types that are isogenic and we could then co-culture, say, neurons and microglia or astrocytes together and study how they interact.

Dr Hazel Hall-Roberts:

We can also reprogram human cells from live patients, as Maria mentioned earlier. We could get someone with an Alzheimer’s risk mutation, and actually reprogram stem cells from them, and study their mutation in the dish.

Dr Hazel Hall-Roberts:

iPSCs are very versatile. With the iPSC-microglia we can actually grow these in quite huge bulk and purity to do high-content screening for potential drugs or potential drug targets. Traditionally, that’s been done with immortalised cell lines but, obviously, with the iPSC-microglia we get some more authentic microglial biology and more authentic phenotypes out of those.

Megan Calvert-O’Hare:

Maybe very quickly you could talk about, because you work on target validation, a bit about that and how you use the iPSCs to do that, maybe even describe how your experiments work?

Dr Hazel Hall-Roberts:

Yeah. Basically, I’m generating, what we call iPSC-macrophages but they’re our most basic model of human microglia and their gene expression profile is quite similar. We can generate those from “differentiation factories”, which is basically a big T175 flask full of embryoid bodies that we can just, siphon, they produce free-floating iPSC-macrophages that we can just siphon off once a week and then feed them again. They’re continuously producing for a couple of months. Then I will take those from a healthy control line and from a line with an Alzheimer’s disease risk mutation in, culture them side by side and perform assays on their phenotypes, basically looking at their behaviour in the dish. I’m interested in phagocytosis particularly, and I’ve developed a couple of assays to study phagocytosis in a more disease-relevant context, so using dying cells, rather than just chucking beads or bacteria at them.

Dr Hazel Hall-Roberts:

Also, I’ve been looking …

Megan Calvert-O’Hare:

[crosstalk 00:22:59], sorry, dying in colour or kill them.

Dr Hazel Hall-Roberts:

Dying, as in apoptotic, as in, cells that are dead.

Megan Calvert-O’Hare:

Right. Okay.

Dr Hazel Hall-Roberts:

Yeah. Although, we have to dye them in order to perform microscopy to study the phagocytosis process.

Dr Hazel Hall-Roberts:

I’ve also been looking at survival with growth-factor withdrawal. I’ve been looking at motility as well, which turns out to be quite important.

Dr Hazel Hall-Roberts:

It’s basically an all-round health testing of the microglia. We want to look at a number of different parameters and see whether any of these are defective with the Alzheimer’s mutation.

Megan Calvert-O’Hare:

You said motility is quite important. How is your culture set up? Are they on something they can move around on? Are you talking about motility around each other? How does it work? Is it a 3D space?

Dr Hazel Hall-Roberts:

It’s actually really, really difficult to study. You can just culture the cells in a dish and create a scratch or have a stamp that leaves a space clear and then just image how they randomly walk towards each other. But without much stimulation they move pretty slowly in a dish.

Dr Hazel Hall-Roberts:

We’ve found that some of the best ways is this fairly old technique with transwells assays where you suspend the cells in a membrane with pores, above the cell culture dish and then put in a chemo-attractant underneath. They tend to walk around, they walk through the pores onto the underside of the membrane and then you can, with microscopy, measure the total number of cells and also the ones that walked through the pores. Then, of course, the stimuli that you’re using may also be quite important in the context of Alzheimer’s disease.

Megan Calvert-O’Hare:

I always like those videos where they show the neurons and they put a bit of chemo-attractant and they go really, well, obviously it’s time-lapsed, they go really fast towards it.

Megan Calvert-O’Hare:

Okay. That’s great. You’re actually testing different small molecules, potential drugs on your iPSC cultures.

Dr Hazel Hall-Roberts:

I have done so in the past with the phagocytosis assay because I got that into 96-well plate format with imaging on the Opera Phenix, but at the moment I’ve been mostly working on the actual validation of the target cells on TREM2, our gene of interest, and just whether we can quite well and quite accurately assess any phenotypic defects. Then we can apply that to other targets in the general TREM2 pathway and we can move forward, potentially, to do some drug screening in the future, if there’s sufficient interest.

Dr Hazel Hall-Roberts:

The main problem we had was, it was suggested that I test a few things, but we weren’t entirely clear whether we were looking for things that increased phagocytosis or decreased phagocytosis, and we’re still not sure.

Megan Calvert-O’Hare:

Okay. Does this come back to what Maria was saying about whether you want to increase phagocytosis because actually you might be compounding the problem by creating more debris, or there’s nowhere for it to go if the lysosomes are dysfunctional?

Dr Hazel Hall-Roberts:

Yeah. It might depend on how you’re doing it, on what pathways you’re activating.

Megan Calvert-O’Hare:

Okay. The stem cell lines or the lines you’re getting from the patients, are they, do they having anything to do with TREM2?

Dr Hazel Hall-Roberts:

We don’t have any patient lines, I know that they’ve been working on them over at UCL and Cambridge, but, no, we’re actually using the other technique, which is having just a healthy donor and then CRISPR-gene editing the gene mutation onto that. Then we have a healthy genetic background, which controls the other simultaneous risk factors that are involved.

Megan Calvert-O’Hare:

So, you’re purely focusing on the function of TREM2.

Dr Hazel Hall-Roberts:

We’re purely looking at that particular gene, and then you can create an isogenic series if you like, in a controlled fashion.

Megan Calvert-O’Hare:

Okay. Emma, maybe let’s move onto you to talk about GWAS, genome-wide association studies. You’ve all been saying the acronym but, so maybe even just go right back to basics and tell us what it is, and how to pronounce it.

Dr Emma Mead:

As you say, genome-wide association studies or GWAS are studies have been performed to identify genes that are modulated or have variants in them, in patients with Alzheimer’s disease. Some of these genes might increase the risk of somebody developing disease and some may reduce the risk. There’s a variety of genes that have been identified in both directions. Several of these genes contain single nucleotide polymorphisms and, as I say, these affect the function of the protein and the aim is to cause changes that affect Alzheimer’s disease risk.

Dr Emma Mead:

We’ve been really interested in looking at these GWAS hits, and really using them as a source of targets to identify suitable proteins to work on. We’re really quite focused and really excited when we see some of these genes that interact in connected networks. If we can find proteins that communicate in distinct signalling pathways, we can find quite a number of different points where we might be able to intervene with chemical compounds. That increases our chance of identifying a drug that we could potentially develop and also increases the probability of us finding something that is safe as well, because that’s quite an important consideration when we look at the immune system, and modulating that.

Megan Calvert-O’Hare:

Have you found hits in TREM2 that then you feed into Hazel’s work, so then she can use CRISPR to introduce those specific single nucleotide …

Dr Emma Mead:

Yeah. It’s well-known that there are several single nucleotide polymorphisms in the TREM2 gene, which are conferring of loss-of-function mutations in TREM2. As Hazel said, the R47H variant is important and that affects ligand binding. There’s another variant, H157Y, that affects the shedding of TREM2, so as a receptor, TREM2 is released from the membrane and we’re looking at ways that we can explore how to potentially affect ligand binding and promote the stability, or inhibit the shedding, of TREM2. We’re quite interested in looking at how those variants affect the function of the protein and understanding the protein and its activity in general, so that we can try and find the best strategy to target it therapeutically.

Megan Calvert-O’Hare:

This is a silly question. Basically, the genetics you’re talking about and the mutations, the patients would have had them from birth presumably?

Dr Emma Mead:

Yeah. Absolutely.

Megan Calvert-O’Hare:

Then this is a disease associated with old age.

Dr Emma Mead:

Mm-hmm (affirmative). These variants are, they range from being fairly common in the population through to be quite rare in some ways, and almost, the more rare the variant, the stronger the phenotype. We know that patients who have mutations in genes such as presenilin 1 and 2, that’s causative. People with those mutations will have, they’ll be the ones to develop Alzheimer’s disease.

Dr Emma Mead:

The genes that are more common in the population have polymorphisms that confer lower risk. It’s really then down to a combination of things like lifestyle factors, environmental factors, and these added affects that you have with the risk genes that contribute to the risk of developing Alzheimer’s disease as people grow older. It’s really all these contributing factors that come together to lead towards people developing disease in old age.

Megan Calvert-O’Hare:

If you’re using a stem cell or iPSC culture you can’t replicate the environment factors that will impact them.

Dr Emma Mead:

That’s quite right. We really use them as a model to understand exactly what that one protein or one gene that we’re interested in is doing, and what the variant does, so that we can really get a much more in-depth idea about really what impact that has on the microglia itself. That will then inform us about how microglia behave in the brain during disease.

Megan Calvert-O’Hare:

We’re coming near the end now. Maybe we can move onto Maria and you can tell us the most exciting things going on in your field of research right now, is one of my questions on my sheet?

Maria Kreger Karabova:

There is so much exciting stuff coming on in the dementia field in general but it’s really hard to pick just one thing. If you go onto Alzforum, the 2019 year was actually described as the year of hope because of so many breakthroughs and the results described.

Maria Kreger Karabova:

I think going back specifically to the role of neuroinflammation in AD, I would pick the growth of data we are extracting in several cohorts from humans. I think this is really important given the doubts as to whether we can truly reciprocate and understand the AD pathology in mouse models of the disease. For example, single cell transcriptomic study on the post-mortem cohort done in Chicago found that human AD-associated microglia, actually only express about some 30 out of 250 genes previously described as AD-associated in mice. You can see that in mice we can get a lot of false-positive hits and vice-versa. We have to be careful about drawing conclusions from the mice studies and the cell line studies to humans. The growth of the human studies is really exciting because it cements the role of microglia in AD and confirms that this is the right direction.

Megan Calvert-O’Hare:

I think, I actually don’t know who’s going to do it or whether we’ve done the podcast yet about mouse-models in AD we should come together and have a play-off between the two of you. When you list the iPSC advantages, it’s like, yes, yes, yes, and then you put the mouse-model on and you’re like yes. They complement each other, let’s say.

Megan Calvert-O’Hare:

I actually have a really mean question. Maybe this one’s for Emma a bit more, as you worked at Eli Lily for a while. Maria mentioned that in 2019 it was the year of hope for all these things, and then loads of pharmaceutical companies cut their neuroscience budgets, departments and things and I just wondered whether you had any thoughts on that, having working in industry for a while?

Dr Emma Mead:

Yeah, sure. We all know that neurodegeneration is a really challenging field to work in, and it’s the patients that we are working towards helping, they have a disease that’s progressed over decades, which means it is very difficult to understand the cause of the disease well, and that impacts the drug discovery effort.

Dr Emma Mead:

I can appreciate that it’s difficult for pharmaceutical companies to find the right way to develop these drugs, to make sure that they are finding the right cohorts of patients to look at in their clinical trials, and really understand the end-points that they’re looking for. That presents a big challenge.

Dr Emma Mead:

It’s a real shame that a lot of companies have decided that they can’t continue with this work, and that’s where institutes like the Drug Discovery Institutes really come to the fore, because we’re working a lot within industry now to de-risk some of the approaches, and do some of the work that they can’t necessarily invest in. That’s a nice partnership that seems to be progressing things well. I hope that that’s something that will continue.

Megan Calvert-O’Hare:

We actually did a podcast with a few people and the ARUK Dementia Consortium, that was the message coming out, was that industry and academia need to work together.

Dr Emma Mead:

Absolutely. Yeah.

Megan Calvert-O’Hare:

Today has been great. Have you got any tips for ECRs wanting to work with iPSCs? Are there any irritating things you find about the cells or any tips at all, maybe, Hazel you love iPSCs?

Dr Hazel Hall-Roberts:

Yeah, sure. You have to find a group where lots of people are doing it because inevitably, when you’re actually growing the iPSCs someone will have to come in and feed them every day.

Megan Calvert-O’Hare:

Even Christmas?

Dr Hazel Hall-Roberts:

Yeah. Most labs have a rota where your colleagues can do it alternately over the weekend, so that you’re not in every weekend. Our lab actually has a stem cell feeding robot for the weekends.

Megan Calvert-O’Hare:

Wow. Is that a robot, or you just call the person the robot?

Dr Hazel Hall-Roberts:

Oh, no, it’s an actual robot.

Dr Hazel Hall-Roberts:

We’re robots too.

Megan Calvert-O’Hare:

Just pipetting, all day pipetting. Maria, any tips for people, because you said you actually worked with patients with dementia, is that right?

Maria Kreger Karabova:

I did, yes, I volunteered in clinic, a low income clinic, particularly, where our task was to translate better because the doctors don’t often have enough time to explain all the nitty-gritty details about what’s going on with the patient, what prognosis they can expect and stuff like that. Our task was to sit down with them in a more calm environment and explain, and comfort a bit, and liaise with the carer and prepare them for what’s coming.

Maria Kreger Karabova:

I would say that having experienced clinical settings and then transitioning to the bench science can tremendously complement not just the skills set but also the results you get out of your work, because you have witnessed both sides and oftentimes they can be quite divorced, so that when you’re working on the molecular pathology you don’t always appreciate what’s going on with the actual person. Having that in mind always, either having witnessed it or perhaps just educating yourself, I know there are many online courses by ARUK/NIH offering the clinical perspective of dementia. It’s fantastic because it really, it helps you understand why you’re doing this to start with and it motivates you further to commence with your bench work.

Megan Calvert-O’Hare:

That’s great. I think more bench scientists and go into hospitals and actually meet people. Well, great. Thank you so much for today. I think we’re going to say goodbye. I’d like to thank you all, Hazel, Maria and Emma. We have profiles on all of today’s panellists on the website, including details of their Twitter accounts, well, just their Twitter handles, not the personal details and passwords. We will also include a link to information on their work. If any of our listeners have questions, we have a busy WhatsApp community group where we host discussions about the topics from the podcasts. Details can be found on our website, so we look forward to chatting to you about this on there. Finally, please remember to like, subscribe and leave a review of this podcast through our website, iTunes, Spotify, Stitcher, Popping, SoundCloud and all the other places you find podcasts. Thank you.

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Brought to you by dementiaresearcher.nihr.ac.uk in association with Alzheimer’s Research UK, and Alzheimer’s Society. Supporting early career dementia researchers across the world.

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