Prof. Carole LaBonne of Northwestern University on neural crest and stem cells

This is the scientific sense podcast that features unscripted conversations with leading academics in a variety of domains. Our goal is to take emerging technical content and make it approachable for public. My name is Gil Epen. If you're watching this on YouTube, there is a link just below to access the full episode. If you like it, please subscribe to it. My question is Professor Carol LeBorn, who is professor of Medical Biosciences at North Western University, and she has served as president of the Society for Development Biology. The research focuses on the genetic and epigenetic control of the stem cell state and its relationship to invasive cell behavior. Welcome. Thank you. Thanks for doing this. I want to go through some of your papers. The first one I have is the developmental and evolutionary origins of cellular pluripotency in the vertebrate neurocrest. As you see here, neurocrest cells are central to vertebrate development and evolution, and doing vertebrates with a new head that resulted in morphological, physiological and behavioral features that allowed vertebrates to become active predators. One remarkable feature of neurocrest cells is a multi-germed layer potential that allows for the formation of many different cell types, understanding cellular and evolutionary origins of this broad cellular potential in the neurocrest has been a long-standing focus for development biologies, biologies. This seems very fascinating, Carol. This seems like a very important thing for vertebrates. This is what really kick them, kickstart them, so to speak, got a head that they can go hunt, open their mouths, and have prey. It's really a very, very important evolutionary discontinuity in some sense, right? Yeah, I mean, it's one of the most important evolutionary novelties that there is. At the base of the vertebrates about 500 million years ago, this stem cell population arose, and it allowed us to develop all the things that make us the large, successful group of animals that we are as vertebrates, including humans, without them, we would be basically soft squishy marine animals like sea squirts. Those are our closest evolutionary relatives, non-vertebrate coordinates. By acquiring this stem cell population, we didn't just acquire that new head, although that's super important, we acquired not just that facial structure that you mentioned that allows for predation, but also a skull to house the brain so it could get bigger without being detrimental, a peripheral nervous system that allowed us to be much bigger animals and still relay information to that brain, a sexual dimorphism through pigmentation, a flight or flight instinct that comes from our sympathetic renal gland. All of these things collectively have a risen from the neural crest and are what we call the primary synoptomorphically of the vertebrates, the shared characteristic that makes them different from the animals they came from. It's amazing, I mean, a singular, well, it's not necessarily singular, but a change that happened in a very short time window had such profound impact on evolution. So in this paper, so we want to talk about the neural crest cells in a little bit more detail. Apparently, they are related to the stem cells, right, in some ways. They are a stem cell population and what my lab showed some years back was that the control of their stem cell attributes is shared with probably the slightly more famous stem cell population that you read about in things like the New York Times. These are the inner cell maths cells or the pluripotent cells that are present in blasterless stage embryos that have been used in regenerative medicine in the clinic. Right, yeah, so they are in some sense similar, but you know, I was looking at some of the videos, I mean, these things sort of start at one point and they migrate all through the embryo and they can create different cell types and all of that. We go a little bit on a tangent gal, I want to understand this. So these migrations that we see of these neural crest cells, are they autonomous or are they guided by some process? So at the beginning, when they are pluripotent, when they can give rise to any of the derivatives, they are not necessarily guided. They say form in one place in the embryo, which ends up being the dorsal part of your central nervous system, and then from there, they're going to undergo what's called an epithelial to mizankomal transition, and that's when they acquire that migratory and invasive behavior. And that behavior is super important because actually that behavior and the genes that control it are what is co-opted by cancer cells at least to metastasis. And in cancer, you don't die from primary tumors, you die from those secondary metastases. The neural crest cells have served as a model for understanding how a cell goes from being part of an epithelial to having this migratory and invasive ability. So to get back to your question, once they undergo that EMT and they begin their migration, they start to lose those stem cell attributes. And what that means is that basically they become better listeners. Now they can listen to cues in their environment that are telling them either what path to take, or what they should become. And so yes, that initial cell doesn't know what it's going to be. It learns that from its neighbors as it traverses throughout the embryo. But an important aspect of stem cell biology is letting go of the, I'm not going to listen to you, I'm going to continue to be able to form anything and begin to take input from your environment that can say, you're going to form a neuron and you're going to form a skin pigment cell and you're going to form a cartilage cell. Yeah, it's a bit like machine learning, in some sense. So if understanding correctly, Carol, you're saying the set of in some direction and the understanding environment and they figure out whether it should end up in where they end up in is quite critical because the destined to create certain specific types of cells. And so yeah, the cancer thing is very interesting, Carol, I didn't think about this. So, cancer is sort of hijacking the same concept you're saying, right? Not just the same concept, the same molecular machinery. So cancer reactivates gene regulatory programs that are, so computer scripts, if you will, that are used early on in the embryo and then go quiet, but cancer cells reactivate them inappropriately to be able to accomplish things that adult somatic cells shouldn't be able to. Well, okay, so it might have some therapeutic potential possibilities, right? So if you study how the embryo develops and as you say, they go quiet at some point after they have done their work, they go quiet. And whatever information we can corner in that process could be quite useful from a therapeutic intervention for cancer potentially, right? Oh, a lot of what we currently use as therapeutics for metastatic cancer, it's derived from studies of cells like the neural crest that can do this migratory and invasive behavior. So these genes were first identified, actually not just in the neural crest of vertebrates, but even in things like a fruit fly drosophila, those same programs are used to mediate a process called gastrelation where cells on the outside of the embryo move into the embryo to approximate the germ layers where they're supposed to be. And so these are, this is a genetic program that's used multiple times over the course of building a body plan and then largely it's not supposed to be used anymore. And so disease processes in particular cancer reactivate things and use them in ways that then further the disease process. Now some of these processes are also used outside of things like cancer. So wound healing, wound healing uses some of those, not the entire pathway, but some of the pathway in order to mediate wound closure, but really, you know, cancer cells which are a lot like stem cells. So if you can think about cancer as a developmental biology experiment, right? So if a cancer is not a lump of cells that are all the same, it has sub-functionalization where certain cells in the tumor, let's say, are involved in attracting the vasculature and other cells are involved in getting rid of signals from their neighbors that tell them to stop growing. So there's specialization in a tumor. Oh, excuse me. So if you are going to want to make a new tumor remotely, so let's say your cancer started in your skin and it's ultimately going to create tumors in your lungs and in your bone marrow. So the cells that leave that primary tumor have to have the developmental potential to give rise to all those specializations to make a new tumor. So it's a little bit like developmental biology. And again, in order to do that, they have to leave that primary tumor and they do that again by harnessing the machinery that cells in the early embryo use to do the same thing. - Yeah, the wound healing is also very interesting. So we don't know anything about it, Carol. So the wound healing requires a lot of transport of cells and mechanically, this appears to be an interesting process they're doing. - Yep, no, it's biology is fascinating. - So let's talk a little bit about evolution. So how did this happen? I mean, before the vertebrates, we didn't have this. And then one day, maybe it's 100 days or 10 million years, something happened in the neuro crest. And we have these very specialized cells that can migrate from there to different parts of the system and specialized. As if their autonomous is taught with some sort of an autonomous program, I'm speculating. And then they're done and they're guided into their ultimate position. And as you say, they go sort of quiet after they reach, they want to reach, right? - Well, the program that has the migrate goes quiet, but they're at what along that pathway, they've been given instructions about what kind of cell they're gonna become. And so then they're gonna be using those genetic programs in order to do the specialization that makes them a cartilage cell or makes them a neuron or makes them a glial cell. So those programs are not quiet at that point because they're going to differentiate into critical parts of the vertebrate body plan. - Yeah, so I don't know who you want to give credit to, is it nature or God, but it seems like she's taking, she's taking a lot of risk here. I mean, this is one of the riskiest process you can cook of. You have all these cells originating in one place and they have to migrate to all sorts of parts of the embryo and specialize. Seems like a very risky process, isn't it? - Well, so nature always has fail safes, if you will. I mean, if you think about it, just the process of a single cell forming you is really remarkable, right? And so along that route, there were cells that made mistakes or didn't do the right thing and your embryonic body compensated by saying, okay, we're not going to use those cells and they put some other cells, okay? So there are, as animals have gotten more complex, they become, we call it regulative, more regulative, which means there's more plasticity in the process to account for something goes wrong and how you can correct it. Now, your original question that you started to ask, how did this happen, right? That's actually been the main focus of my laboratory in the last several years. So we've tied these neural crest cells origins to the origins of those earlier stem cells in the blastula, those pluripotent blastulas cells, yes. And then we wanted to say, okay, but where did those come from? 'Cause it turns out we found that those are also a vertebrate innovation. So our nearest relatives, non vertebrate coordinates, they don't have either of those stem cell populations. So half a billion years ago, at the base of the vertebrates, essentially two new cell types form, those pluripotent cells and then derived from them these neural crest cells. And it's the combination of the two of them that allowed you to form, okay? And so the way we look at things like that is not to start with something like a human because so much has gone on in that half a billion years that we really want to know is we want to look over our shoulder and ask, well, where on earth did that start, right? And so we use something that I think is the inspiration for the Demi-Gorgon, if your listener is want to Google something called a sea lamprey, they should, you know, take a deep breath first because they're pretty ugly looking critters, but they are really important from an evolutionary perspective. So it turns out that there are two kinds of vertebrates, almost all the ones that are living or extant are like you and I, they're jawed vertebrates. But there's a small number of essentially living dinosaurs. There's two of them really, the sea lamprey and hagfish. And they are jawless vertebrates. So they're missing that facial structure that we have. And so they're thought to be even more ancient than the youngest of the jawed vertebrates. And so if we want to know where we came from, we do evolutionary comparisons. So if lamprey, for example, represents an ancient form of vertebrates, if we compare them to another vertebrate, a jawed vertebrate, anything that they share in common was likely a feature of their common ancestor. So basically, if we see it in both of them, then the critter that they are evolutionary derived from likely had that characteristic. And then we've got one more arrow in our quiver, which is those critters that I was talking to you about that are non vertebrate quartets, are closest relatives, they're not vertebrates. And so, Sclona intestinalis, a sea squirt, so a cessile filter feeder in the ocean is a common model for those critters. So now, we can compare a jawed vertebrate, a jawless vertebrate, and something that's not a vertebrate, but it's really close and look at their genes and how they use them and compare. And so what we've found is that where these blastulas stem cells should be in a sea squirt are a population of more limited stem cells called neural stem cells. So they don't have neural crest and they don't have pluripotency at blastulas stages, but they have stem cells that are going to give rise to their central nervous system. And what we've been showing through studies in both lamprey and in a jawed vertebrate, a frog called Xanapis, which is very manipulable in the laboratory, is that it probably only took a couple of modifications to that regulatory program that made those neural stem cells to turn it into a stem cell population that could make more than just neural tissue. - So do we have a time, I mean, it's very, really difficult. I mean, we're talking about long time ago. So you said that three varieties here, there is vertebrates with jaws, vertebrates with our jaws. And there's something that is very close to vertebrates, but it's not quite, and all of them have some innovation, not all of the innovations. Do we have a timeline how this might approach us in the past? - Yeah, I mean, so if you think about what else has happened on the pathway from that C-squirt to you, okay? One of the things that's happened are two full genome duplications. So for every gene that a C-squirt has one of, you have anywhere from one to four of, because that C-squirt genome was duplicated twice, okay? So some of those genes have disappeared because they didn't prove to be useful. In order to be retained over the course of evolution, you have to be selected for, you have to convey some sort of advantage or be linked to something that can be some sort of an advantage. So there aren't huge numbers of cases where you've retained all four of those copies, but they're definitely strong. But then what happens is a process that's called duplication and divergence, okay? If I had one gene that was responsible for doing, let's say, three things, A, B, and C, okay? And I duplicate it, and now they're both capable of doing A, B, and C. I don't have selected pressure to have two of these because the other one can handle it. But what happens? - The same thing happens to you. - Right, it's a redundancy. And if that redundancy just continues, then one of them is gonna be lost by mutation. Mutations are random, lots of mutations are detrimental, so there'll be no selected pressure to keep both of them. But sometimes things change so that, let's say, this one can still do A and B, and this one can be. do B and C. And so now I need them both. Right. And so what happens over the course of evolution, let's, let's look at it this way. I'm going to talk to you for your birthday. I'm going to give you a Lego set. And out of that Lego set, you're going to make some primitive Lego creature. Okay. Not me. I'm, I'm, I am bored about this. And so there Christmas comes along. And I'm going to do a whole bunch of new Legos. And now that's going to allow you to iterate new novelties onto that simple critter that you made the first part. Right. So I have extra bed Lego so I can make more of this. I've got extra blue Legos so I can do that. So basically evolution by having this duplication has given us the tools to take some of those genes and change them slightly so they can take on new roles and eventually can be involved in making new cell types. Yeah. Yeah. So I'm going to go to another paper cows of related papers. So shared regulatory programs suggest retention of blustular stage potential in neural cross cells. So you hear, you see here neural cross cells which are specific to vertebrates, we talked about that rise in the actoderm, but can generate cell types that typically categorize as mess or dermal. So actoderm is sort of in the outer part, mess or dermal is sort of the middle part, et cetera. Yeah. So you can be making an embryo or development as we talk, call it as a process of progressive restriction and potential. So the fertilized egg can form everything. And then we start making differences and propagate those differences so that you can build complexity. Okay. And so the first difference that gets made is to put those Legos into three piles. It represent what we call the three primary germ layers, exoderm, mesoderm, and endoderm. Okay. And so once we do that, the mesoderm isn't supposed to be able to form ectoderm and the endoderm isn't supposed to be able to form mesoderm, et cetera, they've been restricted to a particular germ layer. So neural crest cells have fascinated evolutionary biologists forever because they don't obey germline theory. Okay. So basically they form in the ectoderm, but they can form mesoderm and actually also endoderm we've shown. So basically they return, reach, they retain multi germ layer developmental potential. So there's two ways that could happen. You could reestablish that potential or you could just preserve it, which is in many ways what we call the more parsimonios explanation. And so the first paper that you're referring to, which is maybe 10 years ago now, we showed that we get prided evidence that basically that the retention model was the one that made sense. So even though these cells ended up in the ectoderm, they never let go of the ability to form mesoderm and endoderm. The still have the knowledge and potential. And that is also redundancy in some ways. If things are going bad in one way or the other, they could substitute in some ways. This, I don't know anything about this, Carol, but there's usually a lot of physics involved here too, in the sense that you know the movement of the cells to various layers and the specialization. My intuition is that it has to be guided by physics at some level. I mean, I have no clue about this yet. Absolutely. So I mean, you know, among the biggest advances in this process of turning a single cell into you has been the recognition that of how important both physics and mathematics are to understanding it. There are all sorts of physical properties of cells, not just their behavior like you were talking about, but their shape and their ability to tug on one another. So all of these things are based on mechanical properties of the cells themselves. And so you have to understand, to understand the process, you have to understand not just genes getting turned on and off in the nucleus, but also how that translates into changes in the physical properties of the cells and their contacts. Yeah, so thermodynamics in some sense could be involved. Whenever I see an autonomous migration, my intuition is that it's driven by physics at some level, but then we don't know. You said it starts autonomous and then something else is guiding it to its ultimate position. I would say that there's physical and mechanical aspects to the process that it starts even when it's still a full stem cell. So it has to go from having contacts with its neighbors in a sheet to using those contacts. And instead of having that kind of side to side polarity, it gets free to back polarity, which is what allows you to migrate. And there's going to be two different kinds of migratory cells. There's going to be leaders and followers. So the followers are just going to do what the leaders do, but they have to be able to keep checking and make sure they're doing the right thing. And the leaders are going to interact with the basement level of the tissue and really put force on on philippodia and things to essentially walk across the tissue and generate forward motion. So there's physics involved in all aspects of biology. Yeah. I mean, engineering can learn a lot from this going backward. In the sense that, you know, we have this autonomous vehicle thing going on. And fleet systems. So the idea of the fleet is that each vehicle can sort of communicate with the vehicles around it and make an optimal decision. Perhaps engineering could learn a lot from biology in some way, because I don't think we have solved that problem very effectively yet. Yeah, no, I think it's bi-directional. I think that physics and chemistry can learn a lot from biology and vice versa. You know, and I think that each time there's been a revolution in scientific progress, like the dawn of the molecular error, it's come because rather than each field of the natural sciences and the physical sciences, being its own silo, there were suddenly interactions between them. So basically in the last decade or so, there's been a really renewed interest in applying physical and mathematical tools to understanding biology. And actually, at Northwestern, we have an institute that is funded by the National Science Foundation and the Simon's Foundation. And they collaborate because they each have overlapping but separate interests. So the National Science Foundation is interested in improving our biological knowledge by using physics and math. The Simon's Foundation is very physics and math focus. What they want is to advance mathematics by inspiration from biological processes, right? So I mean, developing embryo is a playground of dynamical systems, right? And so, yeah, systems and with a lot of uncertainty. So you know, the beauty of face like Northwestern is that you can go across disciplines and learn from each other. And that cannot be really replicated elsewhere. And so I want to talk about something that I picked up here. So the ability of neural-crested contribution, Mesodermal derivatives to the, you say it's a bold plan. B-A-U-P-L-A-N has raised questions about. It's a German old German way of saying body plan. Okay. Be embryologists of old German language because they, you know, some of the oldest embryologists were German. Yeah, so I'm at a distinct disadvantage here. I don't know German or biology, but it has to be. Yes, it's questions, you say, but how this apparent gain potential is achieved. So he will describe shared molecular underpinnings of potency in neural-crested and blastular cells. And you talked about this a little bit. So synopos. I don't know if I'm pronouncing this correctly. This is the one with the, with the jaw. The animal with the jaw. X-E-N-O-P-U-S. X-E-N-O-P-U-S? Yeah, X-E-N-O-P-U-S. And then there is one without, without the jaw, right? What, what, what is that thing called? Lampry. Okay. So, so what do we learn? So these are sort of the, the first sample that we have in the two extreme cases is, what do we learn from them? Yeah, so, you know, we're, we're just so privileged to live in an age when it's so simple to do large-scale sequencing of transcriptome. So all of the messages that are present, so okay, let's, let's go back even a little further in the biology. So pretty much every cell in your body has the same DNA, okay? And so muscle cell and a neuron and a cartilage cell, they all have the same genetic blueprint. So what makes them different from one another is what, which of the genes that are in an on-state or an off-state in those different cells, okay? And so we know it's in an on-state because we're making what's called messenger RNA from that blueprint that's going to then be turned into proteins that are specialized for that cell type, right? And so if we want to know what genes are being expressed, we can take those messenger RNAs and turn them back into a DNA copy that we can sequence and we can figure out even at the single cell level what genes are on and what genes are off in any kind of cell, okay? So we can do that sort of within one organism to understand how gene expression is changing over time but what we did in that study was we said, okay, we're going to stage match embryos from these two different kinds of vertebrates that have been independently evolving for half a billion years, okay? And we're going to ask are the same genes on and off in those two sets of neural crest cells and blastula cells, or do they have differences, okay? And so what we found was some differences but the vast majority of genes that were on in a blastula stem cell in a jawed vertebrate were also on in a blastula stem cell in a jawless vertebrate and the vast majority of genes that were on in a neural crest cell, whether in lamfri or in xenopus were the same ones that were on in that blastula cell, right? So we got under the hood and we asked in these two different stem cell populations in these two different critters that have been independently evolving for 500 million years, what are the similarities and differences in the genes that they're expressing, okay? And we found actually that they're so remarkably similar in some cases that there's a one-to-one correlation and not just what gene is expressed but the amount of it that's expressed in a lamfri and in xenopus, again, that are separated by 500 million years of independent evolution, it's just so stunning. So isn't that simplistic, Carol? I'm just thinking, so I'm thinking, look, sort of a bad way of binary switches and some of them are on some of them are off and they take it from two different biological systems and they can sort of outline them and look at the correlations of the switches. Is it as simple as that or something more complicated? It's almost not quite as simple as that, right? So those messenger RNAs tell you what proteins are going to be made, but once you make those proteins, and even to some example for it, but let's just stick with the proteins, you can have something that's called post-translational modifications, you can put little bells and whistles on those proteins that might change their activity, you can locate them in different places in the cell because of that and if they're in one location, they might be off in another location, they might be on, right? And so those modifications are important too and from our study, you can't tell whether those were conserved or not. You'd have to do the same study but use a technique called proteomics, which basically analyzes proteins, but you'd have to use a special kind of proteomics that has the ability to detect those post-translational modifications and these are things that we want to do. So there is more complexity and this becomes really important because if you actually, if you've read that paper comparing the lamprey and the xenopus, you know, we found that one really, really important protein that is involved in stemness and making a blastula stem cell or making a neural crest cell, really two of them, but we studied one in that paper, are the main contributions that probably were added to that neural stem cell back in that soft squishy non-vertebraquartate that turns those neural stem cells into pluripotent stem cells with all this potential and allow the evolution of the vertebrates. And so we took all that data and we said, okay, so that protein in humans is called opt 4 a lot of the time across all vertebrates, it's called pow five. It's part of a large class of transcription factors called pow factors. So we looked in through all the sequence data for many, many, many animals and we said, okay, if only vertebrates have pow five, what do the non-vertebrates have that's most closely related to pow five? Because that's going to tell us what was, so a common ancestor of that pow and pow five was duplicated and then diverged to create what is now pow five and not. So this is where those genome duplication come in. And so that turns out to be a protein called pow three. And you know what pow three does? It's essential for the neural stem cells. So way back, way back more than half a billion years ago, there was a neural stem cell population. And then again, at the base of the vertebrates, we duplicated the genome that allowed that stem cell to form. And there was an ancestral protein, ancestral to extant or living pow three and pow five that was part of that neural stem cell program. It got duplicated and those two proteins changed over evolutionary time to give rise to what in extant or living vertebrates are pow three and pow five, okay. So this is the ability to be a detective though. So we can now compare and we can move around bits of pow three and pow five to try and understand what had to change in that ancestral protein. What sequence is different that created pow five, and therefore created pluripotent stem cells and created you? We can also simulate them with a computing power that we afford now and ask questions around that. But these modifications that you talked about, the gene modifications, I don't know if I understood this correctly. So we have this DNA, you know, a lot of the time we say a good part of it is what it called junk DNA. But it's not quite junk, is it? I mean, it is, there's something there that we haven't quite understood. It feels like. Oh, there's a lot that we understand. It just doesn't get distilled in the in the popular press very well. There isn't there isn't very much of your DNA that I would call junk. There's some regions of repetitive sequences that are left over from things called transposons hopping around your genome in the past. But mostly you have a certain number of what we call genes that encode for proteins. And then you have all these upstream regions that are regulatory. They're switches. They're the parts of the DNA that tell that gene whether it's on or off. And when I said things duplicated and diverged, when I said I had something that gave rise to A, B, and C, and then I duplicated it and now they can both give rise to A, B, and C. And if I make it so this one can only do A, B, and this one can only do B, C, then I have to keep both of them. Those changes were happening in those non-coding regions, the switches, the switch that says A, the switch that says B, and the switch that says C. Right. So let's go to some of a couple of your opinion pieces, which is less technical. Sorry. I find it as simple as possible. No, no, no, I think, I mean, this is sort of practical, a lot of practical questions, as you mentioned on the cancer side, for instance, and we finish up on this. So the therapeutic effects or therapeutic possibilities of these things could be quite enormous for humans. Right. So getting into the hardware of biology in the detailed way has a lot of positive implications at the end. So yeah, so we have to, we have to understand this in more detail. We will get into the funding part of it. But yeah, so without research, we are sort of dead in the water. In some ways, I mean, you can have Washington come out and say if you want to cure cancer, good luck with that. It's fundamental research that ultimately makes a difference. So you have an opinion piece here. It's entitled, why we study shrimp on treadmills? I often wondered this. The case for curiosity driven research, basic science is the engine that drives transformative discoveries. I talked a little bit about this, yeah. Yeah, I picked up the shrimp on treadmills because Ted Cruz was mocking the study in the senate one day. And it does sound absolutely ridiculous. But a lot of things, I mean, Sarah Palin was making jokes about why we study fruit flies. She didn't know how many Nobel prizes that have emerged from studies on fruit flies many. And there are even little soil nematodes or worms called C. elegans that have led to numerous Nobel prizes. So anything that you want to translate or apply. So if you're talking about engineering, that's an application of something. If you're talking about something in the clinic, that's translation. They don't start to know, though. So let's stick with translation and medicine. You know, vast, vast majority of therapeutics and and and approaches to curing and treating human disease did not come from a study setting out to try and cure that disease. It came from basic fun to mental curiosity-driven science about how things work, and then those discoveries had an application that could be used potentially clinically. It's in those translational scientists pick it up and then try and make a drug out of it or make a therapeutic out of it. But if you don't have that initial foundation for discovery, that basic understanding of the world around us, there's nothing to translate and there is nothing to apply. And this is something that even our representatives in Congress sometimes have trouble wrapping their heads around because they're just like, well, don't we know everything? Can't we just translate it and apply it? And no, we might be able to continue that path for a few years, but we would run out of those fundamental discoveries that are going to drive tomorrow's cures and treatments. And I can give you two examples that I think I probably wrote in that paper, one are the glip one drugs that are everywhere and soon coming to a Medicare plan by you. So these drugs didn't come from a bunch of scientists who wanted to understand how to treat diabetes or to treat obesity. They came from some scientists who was really fascinated by a big lizard in the desert in the southwest that could go for really long times without eating. So it fasted for a really long time. It's called a gila monster. Now nobody who wants to solve diabetes or obesity is going to say, I know, let's study the gila monster, right? But somebody wanted to understand why it was this particular lizard could fast for such a long time ago, a long time. And so a compound that was derived from the saliva of that gila monster was what eventually led to the glip ones that are everywhere now, right? And so that was the foundational discovery that built huge transformations that are changing wise constantly. Yeah, I mean, from a policy perspective, funding disappearing for basic science has a lot of different implications. I mean, we will suffer tactically that we can go places. But then we also suffer strategically because last 40, 50 years, a lot of scientists who came to the US from elsewhere, and they made important discoveries. And so if the engine is sort of turned off on basic science, then why would anybody, anybody even think of coming? I mean, place like North Western with a lot of foreign students coming from abroad, they all have different potentially different incentives in the future, right? So it has broad policy implications that we can only measure maybe five, ten years down the road. It's too late by the idea of different countries. What has been happening to science in this country in the last couple of years is tragic. And it is far easier to destroy what has been built since essentially World War II than it will be to try and put it back together again once we move out of whatever strange phase that we're in. You're right. We have been a beacon for the US, have been a beacon for the smartest people around the world who wanted to do science, right? We are unparalleled. We're unparalleled in that step. China is vastly soon going to surpass us. And I'm going to throw a number out there that I think is close, but might be slightly off. So don't hold me to it completely. But I believe that of all the US Nobel Prizes and science that have been won, roughly 40 percent of them were from people who were from outside the country, right? So they moved to the US to do their science. So we're talking about enormous brain drain if those people are not coming here anymore. But the brain drain goes well beyond that. You know, as a scientist on a university campus, one of the things I do is train the next generation of scientists, whether that's undergraduates, graduate students or post-doctoral fellows. And I can tell you that the current generation of students and post-docs are turning away from science. They don't see a viable career path because of the funding issues and other things that are going on to politicize science. And so we're going to lose an entire next generation of scientists within the country. Forget about even the people coming from other countries. And that's not going to just cripple university-based science because laboratories like mine we train the scientific workforce for the pharmaceutical industry, for the biotech industry. So those industries, they rely on the university-based scientists for two critical things. Those foundational discoveries that they're going to build on and the trained workforce that's going to make their translational or applied approaches possible. Yes, again, from a policy perspective, you know, we can measure the net effect for a while. And by the time we measure it, it's too late. And so I don't know. I mean, I don't see the outcome pessimistically. I will say one thing for you that some of the effects are going to be felt sooner rather than later, because it has been estimated that 20 to 30% of the gains in productivity in GDP since World War II have been driven by government investments in the non-defense scientific research enterprise. So a lot of our economic growth is dependent on these wheels that are turning, generating new ideas and so forth. And this is true in every state in the country. And it's been estimated that somewhere between, for every dollar of NIH money that goes to a research lab, let's say at Northwestern, somewhere between 2.5 or $4 of economic activity is generated. So that's the reagents that we buy from companies all over the country, services that we use, the people that we hire. So there's a huge amount of economic engine in this country that's driven by the scientific research enterprise. We will feel that sooner than we feel anything else. And it will be bad, because one of the federal reserve banks, I think maybe in Texas, did a study, a computational study, but they estimated that the 25% reduction in NIH funding that the president asked for in his budget were that to be enacted. It would lead to an economic crisis on the level of the great repression. So that's how much we're talking about that. Science drives productivity and economic activity in this country. Yeah, I mean, you touched on this. If policymakers were to think about this more systematically, it's a national security issue. Anyway, I mean, we have, you know, maybe three or four countries competing with us very vigorously. And if we turn off our engine, we won't be, we won't, we won't win the series at all. And, yeah. So of every drug that was approved by the FDA in the last 10 years, 99% of them started as NIH funded research studies at universities. So if we stop that engine, then all of the drugs that are being made are going to be made in China. Do we want to be completely dependent for our health and and survivability on China's willingness to share those drugs with us? That's the kind of thing that you're talking about. And it's not just biomedical research. The internet came out of NSF funded studies to universities, right? The technology behind Google started in a university. AI started in universities, right? So I mean, all of these things that we look at and we're saying, wow, look what companies are doing. They didn't start in companies. They started by government funded research in universities. Yeah. I mean, more recently, SpaceX, that's apparently 1.5 trillion dollars in market cap or something like that, was rescued by NASA in 2008. And now one guy or a few people have all the benefits of that. So there's a systemic issue here too. Government agencies invest, private companies gone in the benefits of that. So that's sort of sustainable thing either. I would argue. Yeah, I mean, I would never argue that the system we have is perfect. And you hit on one very important imperfection, which is, although Joe Q public is funding for their taxes, those foundational studies, we're so capitalist focused that we don't make sure that some of those profits go back to Joe Q public, right? And so if we were going to have a change in the system, it really should be that these companies that are benefiting from government-funded research in universities have an obligation to give back percentage of their profits to the government when they use those technologies. But that's way above my pay grade. No, absolutely. In 2008, if NASA was a private equity company and the funded, SpaceX was a going bankrupt and NASA gave them, I think, $1.5 billion or something. A private equity entity would have demanded 95% of the company at that point, but NASA didn't demand anything. So the SpaceX shareholders hold all of that right now. So there's something fundamentally wrong. So I want to finish up with this. I have conflicting feelings about this, Carol, so we'll debate a little bit. You say here there is no replacement yet for animal models in medical research. Animal models are made central to understanding the complexity of biology and disease. So I spent some time in the pharmaceutical industry. And I've done increasingly less enamored, I would say, about animal models. As you know, the correlation between animal models and the ultimate success of a drug is very small. It's like 15% or so at best. We have no new technologies for micro dosing and all of that. So it is a question whether we need to do this. So make your argument. Okay. It's an easy argument to make. So first, let's start where you were talking about it in the pharmaceutical industry. I absolutely agree with you that organs on a chip and organ oils and in silico models are increasingly important for drug efficacy studies. I don't think that even in that setting, however, they can replace 100% animal models. And I'll turn around and ask you, would you take a drug that had never been tested for toxicity in an animal model? Could we move directly to humans without ever seeing if it killed a mouse? Yeah, so if I were to go into phase one directly, I'll do very controlled micro dosing type studies. And I mean, I'm not a scientist. Sorry, very controlled micro dosing where in what in a human? You're going to use a human as a human. You're going to experiment on humans and you don't think you're chip towing up to a line there. Yeah, because I mean, ultimately, I mean, we have a sort of 70% failure rate in phase two. So we kill a bunch of mice. But the thing is one is what's important. Don't you want to know that it's not going to kill you before you start micro dosing? Okay. I won't torture you anymore. I want to give an awful lot of brown there. I think I wouldn't take a drug until I know it didn't kill a mouse. Yeah. But I think that figuring out whether it's going to be effective is going to be powered increasingly by AI and in silico and vitro models. I'll give you that. Let's go back to basic science. Okay. So we can make organoids and we can do in silico studies. But the thing is we don't know that they're replicating what normal biology is. The only way we know that that organoid is functioning like an organ is by comparing it to an organ that is not artificially created. Right. So you actually need to know that you got the biology right before you can study that human derived tissue. And in my field, it's even more important than that. So the cells that I study, these neural crest cells, they are responsible for as many as 90% of birth defects in live births. Okay. So they're incredibly important for congenital defects. And we want to be able to know how to change those congenital defects maybe even in utero so that the baby will be born without those defects. Right. So how are you going to study how embryos develop normally to understand how something is going wrong without using an embryo? And we can't do it on human embryos. Right. And the government doesn't even want us to use human stem cells for doing that. And so the only way to understand that process is to study living or animals, living embryos and how they are generating that. And you can say, well, how do we know that it's the same process in a human? And the same kind of comparisons that I was talking about earlier are holds through there. So the things that are in common between lots of different animals on different branches of the tree of life tell you what is absolutely essential. And the things that are different tell you how a human is different from a mouse. Right. And so we can get the essential tool kits, like we always talking about, by studying these non-human animal models. And this is already starting to bear fruit in the sense of they're now two different babies that have been treated with personalized genome editing to correct defects that they were born with. Right. And in one case, saving their life and other case saving their vision. Right. And so this is really remarkable. But the reason we could do that is we understood how those things were normally working by embryo studies. And so then they could say, this is the part that's not working correctly in this baby. How can we fix it? And I'm going to give you one more basic science thing based on that. That crisper technology that is being used now in the clinic to save lives. It didn't come from somebody who wanted to study how to change genes in a human for medical reasons. It came from two with me scientists that were studying bacteria. And they were like, whoa, these bacteria have lots of repeats in their DNA that I've never seen anywhere before. Let's figure out what they do. Right. And so that curiosity driven research helped them uncover that those repeats were part of an immune system for the bacteria that protected them from viruses. And so then they figured out how that immune system worked. And then they realized that they could hijack that process and use it to edit the DNA of any animal they wanted to. But it didn't start with that. It started with curiosity driven basic science. Yeah. I think I think I had the right direction, Carol. I was being a little bit pessimistic. Pre-canical studies. I mean, we used to use dogs and chimps and all of that. I think they moved away from all of that. I don't know. I haven't been in pharmaceutical industry for like 25 years. So we have sort of honed that down to some sort of systematic process. And what you're seeing is that the toxicity studies, the biological system provides a lot of information. That's possibly true, I would say. So I would say it has the additional benefit of being sure. It's an additional benefit to. But yeah, so I mean, just like, I mean, there are activists around. Either the problem is activists don't study science. They just get excited about something. And they go out and activate, so to speak. So that's a problem too. I mean, the same thing happens in climate and other things. I mean, I don't know a lot about this. But so from, I mean, you're an educator. I mean, kids said Northwestern would have learned something. But then we have eight billion people around. And so from a policy perspective, how do we get information out in a systematic way to general public is what bothers me. You know, we don't have a mechanism to do that properly. Well, we're starting to and your podcast is one of them, right? So I think that scientists for a very long time have done a very poor job of outreach to the general public and making them understand what they do. And I think that's starting to change, and it's really important. But there's also been a lot of money and a lot of activism focused on miseducating the public. And so it's, you know, there's a, you know, calling rocks uphill basically is the task at hand. But you know, as often as you'll hear someone say that people don't trust science anymore, I think there was a study in the journal Nature very, very recently, which basically said that's actually not true. Like 73 to 74% of the people in this country actually do trust in value science. It's just that the new. Yeah, it's not as sexy as saying that people don't, right? And so, you know, the basis is there. And there are certain things. I mean, science Friday on NPR's incredibly loved program. The science section in the New York Times also has a huge readership, right? We need more and more of these things, but we also need scientists. of this going out and you know doing science to the general public talks in cafes and other things of some of my students have gone to nursing homes and even prisons to give presentations about what they do and so you know we really just have to look at ourselves not as educators only of the next generation of scientists but also of the general public and you know when I teach my undergraduate courses there's a handful of those students that are going to end up going into medicine or science but every single one of them is going to be a voter so it's my job to make sure that they learn how to think critically about the information that's presented to them and understand how to determine you know what is supported and what is not supported. Yeah so sincerely hope Carol that we get out of this discontinuity we appear to be fallen into and hopefully things will get better yeah yeah thanks so much for spending time with me. Oh it was fun I love talking about what I do for a living. Thank you.