 In Jacqueline Joseph Silverstein, she is our dean and CEO here at UW-Shabuigan. She joined us in January 2013 and prior to coming to our campus, she completed her master's degree in biology from Emory University and her PhD in developmental biology from the City University of New York. She spent two years as a postdoctoral fellow at NYU Medical Center and was a faculty member teaching developmental and cell biology at St. John's University, where she also ran a research lab focusing on the role of a particular chemical signal in the development of the cardiovascular system. So tonight, Dean Joseph Silverstein is going to talk to us about understanding adult stem cells. Thank you. Thanks for all coming out in this cold weather tonight with promise of still a few more of snow flurries. What I'm going to do tonight is take you on a journey through a field of biology that's called developmental biology. This is the field that actually is the foundation for what we know about adult stem cells today and the kinds of studies that are happening right now in this field. I'll tell you a little bit about what developmental biology is in a moment, but first I want to show you a brief movie and hopefully this will help you to understand why I became so enamored of this field and needed to study it for, oh, about 15 years. The fertilized ovum undergoes rapid divisions and forms a blastula. Each division normally takes about 30 minutes. The blastula develops into a gastrula. Neuro folds develop and fuse to form the spinal cord and brain. Eventually the embryos hatch as free swimming tadpoles or larvae. The tadpoles undergo metamorphosis and tiny frogs emerge that eventually grow into adults. So this is the field of developmental biology and those of us who study this field are very, very interested in understanding how you can go from a single fertilized egg to a complex multicellular organism made up of many, many different cells and tissues. So you start out with a single fertilized egg. It divides and becomes a ball of cells. One of the things you saw there over time was that ball of cells seemed to be changing a little and cells seemed to be moving. And what's happening there is the embryo is then forming three layers. And I'll talk a little bit about those three layers later, but I didn't bring a snack with me. I brought what might be some visual aids. So this would be the ball of cells. This would be a really early embryo that we call a blastula. And what happens is at one end it begins to kind of drop in and cells move along the outside and move inside to form the three germ layers. Then the other thing you heard him talk about was the formation of the neural tube and the brain. And what happens is on the outside of this three-layered embryo at that point, on one part of it the cells again begin to move and fold and they form a pocket like that and the pocket comes together and closes with the top being the brain and the remainder being the neural tube which goes on to become the spinal cord. So you've all heard of spina bifida, children that are born with spina bifida. That happens because when the neural tube doesn't close all the way there's some kind of genetic abnormality where their closure doesn't take place. So how does all of this happen? How do we end up with three layers of cells and then an organism with a brain and a spinal cord? Developmental biologists are the people who study the mechanisms for how those things happen. The field of developmental biology is well over 100 years old. The earliest studies were basically done just by looking at embryos like this one through a microscope and watching what happened and then doing some manipulation of cells to see what would happen if you destroyed one cell in a four-celled embryo. How does that impact development of the rest? To now using molecular biology and genetic engineering to try to get deeper and deeper into an understanding of how an organism develops. This is just a picture of that ball of cells I was telling you about when it has formed the three germ layers. And I'll talk a little bit about those germ layers in a minute. But if you were to cut this orange in half, if this was an embryo, a three-layered embryo, this is what you would see. And these are frog embryos. Human embryos develop a little bit differently. And I'll mention that briefly when we talk a little bit later on about embryonic stem cells. So how does all this happen? Well, the first thing you need to understand is a little bit of cellular biology. And I've been showing the top part of this slide over probably over 20 years now because I always remember when I was in elementary school and the teachers would tell us the cells are the building blocks of life. And I'd always picture like this brick wall. And these were the cells. They were these inert things that were just sitting there. And then you get a little more advanced in school and they start telling you, well cells have organelles inside. They have the nucleus inside that contains the DNA. And they have the mitochondria that are the powerhouse of the cell. And then I was kind of picturing this brick wall, but they had organelles in them. They had nuclei in them. Well, this is not what cells are at all. Cells are, they behave. They have behaviors. They can divide just like you saw in the movie. They move. As I said, these cells are moving around in these embryos to form these three layers. They send signals to each other. Cells can send signals and cells can respond to signals. They stick to each other to form sheets. And sometimes it's in sticking to each other that those signals are sent from one cell to another. And then cells also become differentiated to perform specific tasks. You have an egg and then you have neurons that form specific tasks of sending nervous impulses through the body. You have a liver with hepatocytes that have digestive enzymes in them. You have muscle cells that contract. Those are all differentiated cells. They have specific functions. They're not the same as the egg or those early cell divisions that we saw earlier. So, when the cells form those three layers, each one of those layers goes on to become particular sorts of tissues. And the three germ layers, as you might, you can kind of tell by the names, ecto is outer. So, the ectoderm is the outer layer of cell. Endo is the inner layer of cells. And the mesoderm is the middle layer of cells. And each one of these layers contains the precursors of all of the cells that make up the tissues that you see here. So, when I was doing research, I was specifically focused on the cardiovascular system. And so, I was looking at cells that were derived from this middle layer or the mesodermal layer. So, I mentioned cell differentiation. I said that's one of the behaviors of cells. They divide. Well, what is differentiation? Differentiation is the process by which cells become specialized. And it happens in sort of a sequential way. The egg is what we call todipotent. It's able to make any kind of cell type at all in the body. Over time, a cell's fate begins to be narrowed somewhat. And then cells are pluripotent. Plurie means many. They can become many different types of cells if they're in the right environment and treated the right way. And then, ultimately, they're differentiated. They're only one cell type. They have a job to do, and they can only do that job. Now, when I was doing research, we believed that this pathway could not be reversed, that it was irreversible. You could never go from a differentiated cell back to a pluripotent or a todipotent cell. And what I'm going to talk to you about for at least half of the night tonight shows exactly that. That we can go from a differentiated cell to a pluripotent cell if we treat the cells appropriately. And the whole adult stem cell field, as it exists today, is based on the ability to reverse that so that differentiated cells can become pluripotent again and therefore become many different kinds of cells. And this is just a little diagram that the fertilized egg would be on top, and the fertilized egg would have the capacity to become any of these eight or nine different cell types. But over time, you see the branches, cells have a lesser and lesser ability to go on to become particular cell types. Their fates become narrow. Eventually, they are differentiated and they do the job there they were determined to do, to secrete digestive enzymes or to contract like a skeletal muscle would contract. So stem cells, stem cells are cells that are able to renew themselves and stay in an undifferentiated form, but they're also able to differentiate into mature cells. So the example of stem cells that we have the most knowledge about, we meaning everyone in this room, is bone marrow cells. So we know that we have stem cells in our bone marrow that can go on to differentiate into white cells or red cells or blood platelets. Those cells are able to renew themselves, so you always have a pool of stem cells that when necessary, go on and differentiate into each of these different cell types that make up the blood. And a lot of the early work in this field was done on blood cells. So how do cells become differentiated? Remember I talked about the fact that cells can send signals and cells can respond to signals. Well, the whole process of differentiation is based on cellular signals. And this is just a diagram of the surface of a cell and on the cell you have something called a receptor. And a receptor, you can kind of think of it like an antenna. And there are thousands and thousands of receptors that respond to different kinds of molecules on the surface of the cells. And when the right molecule comes in contact with the receptor, it sends a signal inside the cell and there's a whole cascade of things that happens that scientists have been studying for 20 plus years now that then tell a cell to behave in a particular way. When we're talking about differentiation, much of what happens is the signal that is sent inside the cell somehow impacts the DNA in the nucleus and impacts gene expression. So gene expression, DNA, genes are on the DNA. They can be transcribed to RNA. RNA is then made into proteins. Okay? There are some those who are molecular biologists know there are some other things that can happen too. But that's kind of the basic tenet. And so what happens, what we know about differentiation is that some of the chemical signals come from the outside of the cell like this. There are actually other signals in the cytosol. That's the cytoplasm, the soup that's inside the sac, that's the cell. And they all interact with the genes inside the nucleus to turn genes on or to turn genes off. So the word differentiation means becoming specialized or different from every other cell type. And the process by which this occurs we call differential gene expression. Different genes are turned on at different times. And there are factors in the cytoplasm that bind to DNA. That's kind of a simplistic way to think about it and turn certain genes on and turn certain genes off. And I think this is kind of a neat diagram and it's something I never did. This technique has probably just come about in the last ten years. But it uses bioinformatics. And bioinformatics is really the ability to use computer programs and that kind of thing along with quantification of signals to be able to look at different gene expression. You can use bioinformatics in a lot of things, but this one is gene expression. And this is called a heat map. And what you have here is across, in the horizontal direction, these are all different types of cells. And then vertically these are all different genes that might be found in these cells. And the brighter the red, the higher the level of expression of that particular gene. So what you can see is every single cell type that you see here has a different pattern. And I wouldn't call it a fingerprint because that actually is something in biology, but it's kind of a signature. So each cell type has its own signature of gene expression. So if you think about it, there are certain kinds of proteins that all cells have. All cells have a shape and that shape is brought about by certain kinds of structural proteins that form scaffolds inside the cells. So you would expect to see those kinds of proteins and those genes expressed and all the cells you're looking at. But on the other hand, a neuron will have a gene for a neurotransmitter. A muscle cell will have a gene for a particular kind of contractile protein that are only found in muscle cells. And the hepatic cell will only have genes turned on in addition to the ones that are always turned on to make digestive enzymes. You're not going to see all those things turned on in all those different kinds of cells. That's what makes the cells different, which genes are expressed in those cells. And as I said, this is a really neat technique that obviously allows you to look at lots and lots of cells and lots and lots of genes all at the same time. So we now know that cells differentiate. We think, at least up to this point, that that differentiation is irreversible and we know what a stem cell is. A stem cell is a cell that can not only renew itself but can differentiate into a different kind of adult cells. And I'll use the word somatic for adult cells. You have the fertilized egg and then you have the somatic cell, somatic soma's body. So you have the cells of the body. But now I'm going to talk a little bit about the experiments that were actually the kind of breakthrough experiments that ultimately led to the current work that's being done in the adult stem cell field. And this was actually a cloning experiment and this was done way back in 1952. So a major question in the field of developmental biology is how do cells differentiate? Why does this cell become a skin cell and this cell become a muscle cell? And very early on there was some thought that perhaps the way this happened is that some of the nuclear material was lost over time. So when you became a two-celled embryo, each cell got half of the genetic material in the nucleus. And when you became eight cells, each cell had only an eighth of what was found in the nucleus. So the questions that scientists began to ask was, well, are nuclei all the same or not? You know, if we could show that nuclei were all the same, then that would give us some information. So this was an early experiment and this gentleman really did it to perfect a technique that he could use later on to answer that question about whether all nuclei were the same or whether they were different as the embryo continued to develop. Briggs and King, they were in the United States. I think they were in Indiana, actually. And what they did is they used a frog called Ronapippans and they developed a technique that sounds easy, but I can imagine the meticulousness and the eye-hand coordination that was required to do it. They took an egg and they removed the nucleus from an egg. All this obviously needs to be done under the microscope. Then they took a cell from a blastocyst. Now a blastocyst is an embryo just at the stage where it's a ball of cells. They took one of those cells and they removed the nucleus from it. And they took the nucleus from that one blastula cell and they injected it back into the egg. And what they were looking for was, all right, can this cell from the blastula now cause this egg to develop into a frog? If it could develop into a frog, it would mean nothing was lost from the nucleus during the early stages of development. It would mean everything was there that was needed in the nucleus and there was something else that was going on that was causing differentiation to take place. And what they found was when they did this experiment with these early embryos that were just a ball of cells, when they took the nucleus out of one of those cells, they got some swimming tadpoles. About half of those eggs developed to a ball stage themselves and of those a certain percentage went on to become tadpoles. Now that was pretty cool and that would make you think that the nucleus must contain all of the genetic information to direct development because you could take a nucleus out of the 128 celled embryo and get it to direct the development of an egg again. Well, but then Briggs and King tried to do these experiments on the little later embryos. They took the embryos with the three layers that are a little later. They took nuclei out of those and they got very little successful development when they did that. So at that point, not quite sure, does the nucleus contain all of the developmental information no matter when you take it out of the embryo or is it only at the earliest stages? Is something being lost with later development? So then along comes Gordon, who I believe was at Cambridge, and he actually took advantage of the technique of cloning that Briggs and King had developed. He was a different species of frog and he used adult cells. He took adult, first he started with intestinal epithelium cells. He took a nucleus out of an adult intestinal epithelial cell, put it into a frog's egg that had been enucleated. Enucleated means the nucleus had been removed from it. He put the intestinal epithelial cell inside that egg and he got some swimming tadpoles. Those adult nuclei were able to direct the development to the point of a whole swimming tadpole. Now you can see this experiment shows a skin cell. Well, people didn't believe Gordon. After all, Briggs and King couldn't get it to work after a certain point in time. So why are they going to believe Gordon in England who's doing these experiments? So instead he tried them again using a skin cell and so a skin cell would have a pigment to it. So you would really know that the nucleus you were taking was coming out of that skin cell. When he was doing the experiments with intestinal cells, people said, oh well maybe he's not really getting an intestinal cell. Maybe there are some early cells in there and he's getting those. But when he used a stem cell he was able to show that was exactly where he was getting those nuclei from. And again he was getting swimming tadpoles. So these are both cloning experiments done in frogs that ultimately show that the nucleus contains all of the information necessary to direct the development of a whole organism, to make cells differentiate into all of the different cell types that there are. Now I always can't resist talking about Dolly because when Dolly was cloned in 1996 it was a huge deal and the newspapers ran with this one for weeks and months and then dogs were cloned and cats were cloned and all kinds of things were cloned. And of course those of us in developmental biology said, what's the big deal? This was done 30 years ago in a frog. Well the big deal I suppose you could call it is it had never been done in a mammal before. And so this was the first time a mammal had been cloned and what they used to clone Dolly were cells from the mammary gland. So they used two different species of sheep so that they could tell by looking at the genes which nucleus or which nucleus the new embryo came from. And what these guys also in England or Scotland I guess were able to show was that they were actually able to get a complete sheep by using an egg from a Scottish blackface and the nucleus from an adult again an adult cell a differentiated cell mammary gland cell. And they got Dolly. Now one of the things that you need to know is yeah this can be done. It's been done in lots of different species now. Probably the efficiency of this is maybe between one and five percent. So you know you need a hundred eggs to get to get one Dolly basically. And the other thing that's interesting to note is that Dolly you got there. I don't know a lot about sheep but Dolly appears to have died prematurely. She died at the age of eight. She had really bad arthritis and a bunch of other problems as well. And you know when some of that may be the result of the fact that she was cloned and there might have been some genetic issues that were related to that that didn't show up until later. But I always have to talk about Dolly because Dolly is kind of the point in the field where everybody now has said aha developmental biology and cloning this is happening. You know this is amazing stuff and everyone now was more focused on this field than they were back when I was doing it back in the 1980s and 90s kind of thing. So as I said what we now know are genes aren't lost during the development and the nucleus from a differentiated cell like an intestinal cell or a skin cell or a mammary gland cell can be what we call reprogrammed back to that pluripotent early state where then if you treat them the right way they can go on and become a different kind of differentiated cell. And I'll talk a little bit more about that in a second. So here's a good point for me to mention what one of my basic take-home messages is every time I talk to an audience where there aren't a lot of scientists in the audience and that is a lot of major breakthroughs that impact what we know about human disease and how we can treat human disease come from basic biological research. No one sets out to say I want to clone a sheep just for the heck of cloning a sheep. They ask the question I want to understand more about differentiation. I want to understand if a nucleus is altered or not during the course of development and it is during the process of trying to understand more about the mechanisms of development that you sometimes have these amazing findings that later on become breakthroughs in the field of biomedicine. So I always kind of like to make that point. I remember when I was working on my master's degree I was working on salamander fertilization and I remember my smart alec brother-in-law saying, so who cares about salamander fertilization? And even then when I was much, much younger I knew enough to say well if I understand how this works in a salamander, if I understand how sperm are able to penetrate eggs in a salamander that could help us to understand how that happens in a human. And obviously over the years they have come to understand that and it has helped a lot with methods for in vitro fertilization and also methods to inhibit contraception as well. So out of basic research comes those breakthroughs that end up changing our lives and our health sometimes. So this whole cloning thing and showing that differentiation can be reversible led to a new thought. Can we use stem cells to renew damaged tissue and cure disease? I like to talk about the search for the holy grail and by the way we talk about tissue regeneration. So tissue regeneration is just what it sounds like being able to take stem cells and regenerating new cardiac muscle or regenerating new neuronal networks. And in fact you'll see that there are people now who call themselves regenerative scientists and there's a field of regenerative medicine and lots of very well-known medical schools all over the country have institutes of regenerative medicine and what they are all doing is studying stem cells because there are so many ways that we believe now stem cells are going to help us to understand disease, help us to discover new drugs and perhaps even eventually help us to treat diseases. So there are several different kinds of stem cells and the ones that most people know about are embryonic stem cells because those are the ones that have made their way over the years into the newspaper and into the controversy over whether or not scientists should be using embryonic stem cells. So embryonic stem cells are just as they sound like from the embryo. I showed you the development of a frog but mammals develop a little bit differently and the way mammals develop is they have an outer layer of cells and that outer layer of cells goes on to become the placenta and then there's a little mass of cells inside that's called the inner cell mass the entire embryo develops from that little small mass inside and embryonic stem cells are made by removing cells from that inner cell mass growing them up in culture and now you have embryonic stem cells that if you treat them the right way you can get them to differentiate into other cell types you can get them to differentiate to cardiac cells into neuronal cells into hepatic cells into many many different cell types and that's because since they're from a very early stage embryo they're pretty close to being toady potent they have that ability to become almost any kind of cell in the body or actually any cell in the body so those are the embryonic stem cells and before I came down I double checked when they were first isolated they were first isolated in mice in 1981 and then not until 1998 from humans and actually I remember probably in the early 90s I was studying a protein that I believed was important in the development of the cardiovascular system the reason I believed that was because I was able to track development I used chicken embryos and a chicken embryo and show that this particular protein showed up in the heart and in cells that went on to become endothelial cells or capillary cells at particular stages in development so usually if a protein or a gene is expressed at a particular time very often that tells you something about the fact that it might play a role in that particular time in development and so I remember there's a place that you can get cell lines called the American Tissue Culture Consortium or something like that I don't remember what the second C was but there are thousands and thousands of different cells you can get from this organization that you can then grow up in your lab and treat however you want and I remember taking mouse embryonic stem cells they would send them to you in a test tube and you would put them in a dish with the right kinds of nutrients and watch to see whether or not you could get them to differentiate and because I believed my molecule wasn't my molecule but my molecule was involved in cardiac development I would treat these dishes of cells with the protein that I was studying to see if I could get cardiac cells to develop anyone have an idea how you know if you have a dish full of cardiac cells? anyone know? any of the biologists in the room? so if you have a dish of real cardiac myocytes, cardiac muscle cells they begin to beat and when they form a monolayer where they're all touching each other they beat synchronously so when they're kind of just spread on the dish here and there this one is beaten like this and this one's got a little bit of a different beat but once they make contact with each other they all take on the same beat and that's how you know you have a dish of cardiac muscle cells cardiac myocytes well I never saw that and soon after I became an administrator since then, I have to say that since then what I've learned is that that protein that I was studying has been shown to be involved in cardiac development and in fact they're using it as part of a cocktail to take some stem cells and make them cardiac cells I just didn't know how to do it and didn't know what all the other right nutrients were that were supposed to be there at the time it's 20 years ago now then there's something called adult stem cells and there's still a lot of controversy about whether they exist or not you know, for a long time people were certain there was no such thing as an adult stem cell with the exception of skin turns over very very quickly obviously there must be skin stem cells blood turns over very very quickly we know there are blood stem cells in the bone marrow but people did not believe there were anything like neuronal stem cells or cardiac stem cells or muscle stem cells and for a while back in the early 2000s there was a flurry of work being done that made people think there were likely cardiac stem cells and neuronal stem cells I think later research is the thinking now is that they're not actually stem cells they're cells in a tissue that can divide and then differentiate so they're kind of a pool of cells but they're not stem cells from the perspective of being pluripotent they can't become lots of different cell types the thinking now is that maybe there are some cardiac stem cells the only things they're going to do is become cardiac cells they come to the rescue when tissue was damaged basically so that field maybe doesn't have as much promise for taking a cell, making it pluripotent and then growing it up in large numbers making it any kind of cell you want then there was something called mesenchymal bone marrow cells and these were cells that were not blood cells in the bone marrow but some of the other cells that are found in the bone marrow that people believed were pluripotent and as I read the literature I think they now believe that while they become all the different types of skeletal cells that exist bone cells and cartilage cells and some other connective tissue cells they can't become other kinds of cells outside of that cell lineage or group of cell fates that's related to skeleton what appears like it might be the Holy Grail although a whole lot of work is still being done on embryonic stem cells are these things called induced pluripotent stem cells the name in itself is kind of daunting to understand what that means and these are adult cells that can be reprogrammed back to almost an embryonic state they can be de-differentiated remember I said we didn't think the arrows could go that way the arrows could only go that way but these are cells that you can reprogram back to an undifferentiated or embryonic like state and then by using particular signals sometimes you actually have to get genes inside the cells sometimes you can grow them in a particular cocktail of molecules you can get them to go on to become a differentiated cell induced because an induction needs to take place you have to force them back to an embryonic state and then you have to induce them to become a new differentiated cell type and that really appears to have a lot of potential and there's a ton of work being done on those cells right now because none of this stuff is easy you have to figure out what kinds of chemicals they need to grow in sometimes you need to grow them with another kind of cell there might be another kind of cell that produces just the right signal that those cells need well now you have two kinds of cells in a dish and you've got to purify those cells that are just helping your cells grow from the ones that you want you have to make sure that you're turning on the right genes so they're differentiating along the pathway you want them to so none of this sounds easy and work is continuing just on being able to get decent populations of these induced stem cells now they can become there are several types of cells that they've been able to show they easily become it turns out that these induced stem cells can fairly easily become cardiac cells and neuronal cells, nervous system cells they can also become blood cells they can also become hepatocytes those are the things that require the least manipulation to get them to go down those pathways so pluripotent stem cells the Nobel Prize actually was awarded to Shinya Yamanaka but also Gerden remember Gerden from the frog experiment earlier? the two of them together were awarded the Nobel Prize in 2012 and obviously hopefully now you can see the bigger picture that Gerden's work really laid the foundation for this work Yamanaka did where he was able to reprogram adult skin cells back to an embryonic like state first he did it with mouse and then he did it with humans and they can show that these cells that were skin cells when you reprogram them back to an embryonic like state can go on and become cells of any of those three germ layers remember we said those three germ layers each was responsible for different tissue types in the body and there are a couple of ways to show that they can grow cells in dishes and do genetic analysis and show what kinds of genes they're expressing there are also things you can do like inject them into a mouse and they'll form teratomas and teratomas are kind of benign tumors that contain cells from a lot of different tissues they can be kind of funny looking they can have a little cluster of beating heart cells and they can have cells shooting hair out of them and they can have a little cluster of liver cells teratoma kind of monster like and that's where that name comes from they're these weird monster like clusters of cells so you can take these induced adult skin cells you make them embryonic like you inject them under the skin of a mouse embryo and they form these embryo like things that have all these tissues in them but not organized necessarily into a nice embryo at least not in the early days of showing that these cells can produce all of the cells from all three germ layers but I thought it was interesting I was wondering why Briggs and King didn't win this Nobel Prize at all and I don't know if they would have or not but as my husband pointed out to me the award the prize is not giving posthumously and both Briggs and King were long gone by 2012 actually so I don't know if that's why or if there was some other reason why they wouldn't have gotten it if they were still with us so this is just a little schematic of how making induced pluripotent stem cells work you take a differentiated somatic cell remember cell of the body, skin cell maybe white blood cell those are if you think about it those are the easiest ones wouldn't it be great if you could just take a little skin biopsy or take a mill of blood de-differentiate those cells make them any kind of cell that you want them to be I mean that's the hope that's the holy grail really that we'll be able to do that at some time you can reprogram them back to an embryo-like state and then that's when they're called the induced pluripotent stem cell and then remember their stem cells so they can renew themselves they can keep growing and some of them can be, you can differentiate into all of these different cell types so why the big hoopla about stem cells these days I won't separate embryonic from induced but obviously this has a lot of great potential because you'll be able to get these cells without being invasive really from an individual and if you think about it if I need and we're near here yet so I'm not saying we are but if I have a damaged heart if I have cardiac hypertrophy we could take a skin biopsy we could de-differentiate those cells into pluripotent stem cells we could grow large numbers of them maybe we grow them on some kind of scaffold three-dimensional kind of scaffold we differentiate them back into cardiac myocytes and they're my cardiac myocytes they have my genes my immune system is not likely to try to fight them off because they're me so think about it that could be a huge breakthrough in modern medicine if we can get to that point where those kinds of things are happening but there are a bunch of other ways you can use stem cells as well and some of them while they might not be direct treatment of disease they are gonna aid in drug discovery so for example one of the big parts of drug discovery is toxicity a lot of drugs are either really toxic to the liver or really toxic to the heart well imagine if the way you could study toxicity of drugs you're trying to develop is just by having dishes and dishes dozens of dishes of heart cells or liver cells and being able to test all of those potential drugs directly on those cells and in fact one of the articles I was reading there's actually a company now that is selling I think it's cardiomyocytes they're selling cardiac cells for that very purpose to be used by pharmaceutical companies for toxicity studies so you know the stem cells in that case are not being used to cure human disease but they are being used to hasten the pace of drug discovery and to also probably some day limit the number of clinical trials that have to be done because very often toxicity is a part of clinical trials as well how high a dose can you use to get an effect and not harm the patient too much anyway so the other things that you can do with these I've seen it referred to as disease in a dish so we use a lot of animal models to study disease but the problem sometimes with animal models is they're not exactly like the disease we have as humans they mimic that disease so they're not perfect models and even when they are perfect models sometimes because of their metabolism for example the heartbeat of a mouse is x number of times faster than a human when you look at potential drugs on these animal models they may not be giving you the same kinds of results as they would in a human but imagine if you had dishes of cells from a thousand different humans and you could test the same drug on a thousand different humans by looking at using a disease in a dish it would someday could decrease the clinical trials that would need to be done or clinical trials perhaps would just be the latter part of the drug discovery process and not happen so early in the drug discovery process the other thing people are using them for is to just study disease so there are now a number of diseases where they've been able to take cells of humans, skin cells de-differentiate them and re-differentiate them and most of these diseases into a kind of nervous system cell neuronal cells and the reason they're doing that is because they're trying to understand the disease if they can recapitulate the development of the cells prior to the disease happening they may find out oh well this is interesting this gene is turned on abnormally in the cells from the patient with Huntington's disease they're turned on at a different time than the cells in the normal patient so maybe this is the disease target that we should be looking for a drug to discover so these can be used to look for targets for drugs they can be used just to study disease and get a better understanding of disease they can be used for cyto they can be used for toxicity studies as I said before someday we hope that we can actually use them for treatment and small molecules on cellular targets this is again part of drug discovery so there are things happening every day in this field and one of the things that I was able to do before I came down was to find a nice timeline of stem cells and you remember that Yamanaka made the first induced pluripotent stem cells in 2006 in mice in 2007 in human but then we skipped down to 2010 and a lot of this is happening in dishes right now in culture dishes reprogramming mouse non-muscle cells into beating heart cells converting human skin cells directly to human blood cells in 2012 this is an interesting one scar tissue that formed after a heart attack can be reprogrammed de-differentiated into induced pluripotent stem cells and reprogrammed into beating heart cells and living animals you can reprogram skin cells from Huntington's patients and a cell culture model that's what I was talking about before and there are a couple of clinical trials do I have that here? yes, coming soon age-related macular degeneration I think that clinical trial if I remember correctly is going to be happening in Japan and potentially Parkinson's disease too so the first two human clinical trials are on the horizon using these induced pluripotent stem cells at the same time they keep on trying to work on methods to make it easier to make these stem cells to make it more reproducible to make these stem cells and you can see there's actually an animal model where they've been able to cure sickle cell in a mouse by taking by reprogramming cells back to pluripotent stem cells skin cells I believe adding the genes doing genetic engineering to put the right gene in these cells as opposed to the gene that causes the sickle cell disease and then injecting that back into the mouse and getting red blood cells now that are sickle gene free that has been done now in animal models they've been able to take human cells that they have differentiated into neuronal cells and that basically I think the study they showed that it improved the gait of Parkinson's mice so that they were walking better and that kind of thing and then in ALS there's also been some work that's actually been done on the whole mouse now so there is great potential for adult stem cells and stem cells in general and I just wanted to I was amazed at when I googled stem cells here's an article February 2014 reprogramming skin cells into beating heart cells 2014 there's another one about being able to reprogram skin cells into hepatocytes which are liver cells and growing them on a scaffold so there is huge potential for this it's not going to be tomorrow that we are going to see diseases being cured using stem cells but certainly they're going to increase the pace of drug discovery and helping to cure human disease and hopefully 10 years from now if someone comes back and talks to you about this again there will be some major breakthroughs and they will be able to talk about the results of these clinical trials and the success of these clinical trials so thank you questions? Dave what exactly is the advantage of using induced cells rather than embryonic stem cells? well that's an interesting question obviously one advantage is you bypass all the ethical controversy that's going on about embryonic stem cells but I mean that's one and you read that people when you read the articles they talk about that but I think the really important one is what I said before it's non-invasive and it's your own cells so likely if you get transplanted with your own cells you're not going to your immune system isn't going to fight them off you're not going to have a kind of graft versus host response early on there was some fear in the work they were doing in mice that there was some graft versus host response but it appears that as they've gotten better and better at this some of the more recent studies they did to look at that showed that that wasn't the case so that's really the major I'm not being facetious though about the other one because articles usually do point that out too as an advantage but I think the main biological advantage is itself and it's not that invasive you can take a mill of blood you can take a little skin punch and you can get it what's the advantage of using the embryonic cells rather than the induces? well because we know that it's not yet been showed that those pluripotent cells can become every single type of cell we know as I said they can very easily become cardiac cells in hepatitis sites which is really nice because those are the two things where drug toxicity is greatest in so it's great that we can make large numbers of those they also can do neurons in blood I'm not sure that it's been easy to get them to differentiate into other kinds of cells yet that we might be interested in the embryonic cells are truly totipotent now there's also another disadvantage to the embryonic cells I don't think you can grow them yet without a feeder kind of cell you know I talked about the fact that sometimes you actually need another kind of cell growing right alongside them in order to get them to do what you want to do and that was the case for embryonic stem cells and I think it still is so that's another disadvantage to those but the advantage is that I think scientists believe they really can become any kind of cell that we might want them to become yes? neurons so in fact and I think some of these like the Parkinson's disease study I talked about if I'm not mistaken those were actually neurons that they then injected I think I could be wrong about this into the brains of those mice and like I said it kind of improved their gait when they did that so remember you're not transplanting a brain what you're doing is you're providing some normal tissue in a place where there's damaged tissue the cells as opposed to the whole animal not that much yet it's all of that kind of work that's really done it depends on what stages of drug discovery because when you're talking about cures you're actually talking about drug discovery in the very early stages of drug discovery when they're just testing compounds they very often start out testing those compounds on animal cells but some of the work we're talking about here is very very new and has only been done for the last three or four years but very often kind of that's the first stage you have animal cells you have animal models there's about a fourth stage that's my presentation tomorrow there's about a four or five stage process to drug discovery that can take as much as a decade and during some of the very early phases of that there could be animal cells used to try to identify the right target drugs for cells yes I know people though that have had stem cell transplants blood cell transplants so you're absolutely right that is very different from induced pluripotent stem cells as I said early on that what we're almost familiar with in terms of a stem cell are the cells in the bone marrow so the bone marrow normally contains stem cells I used to know this I don't anymore but I think a red cell turns over every 90 days or something so you have to have a source of cells to be able to keep replacing the red blood cells so yes, blood stem cells we know they exist and it's been a godsend for people with cancer you have had a stem bone marrow transplant my husband is a hematologist but also blood cells yeah so the bone marrow of the blood contains all the progenitors to all the kinds of white blood cells as well as all the well the one kind of red blood cells in the platelets so sometimes you find also can find some of those early stage blood cells circulating as well is that what they did with you they took circulating cells took it out of one arm but I still out to lunch on how they separate these things I know who knows how to get where you know how you get the right ones and the ones that you don't want in your body you don't get in your body yeah I wish my husband the hematologist was here tonight he could explain that do you other questions so the differences is that most of these are cells that most of the cells I talked about were some sort of already mature cell that to be embryonic like and then made them into a different kind of cell the blood cells are a different case they already exist in kind of that stem-ish stem-ish form well thank you oh Patti developmental biology in particular a fabulous professor in college a really amazing professor when I took developmental biology and then when I was a senior I worked in this lab and that was that was what really sparked my interest Dave did you have another question yes he's the ethical issue uh oh that was the gloss I'm just curious how much the restrictions of the previous administrations of restrictions on the use of embryonic stem cells how much of those restrictions uh are basic research and understanding of well certainly they slow down our our greater understanding of embryonic stem cells in their use you know there are still these I don't know how many 20 different cell lines that were already in existence before the law came into being and there were still people all over the country including Harvard that are working on those 20 cell lines but the inability to be able to generate more of those cell lines you know I would think if I were in that field I would be frustrated by it and it probably not probably it would impact your slow down and impact your ability to to ask all the questions you can think of because you really don't have all of this to work with you have a very limited number of sources of cells that you can work with in fact I did know someone who was at Harvard who really became very very well known through the work he had done at embryonic stem cells and I don't know why he's not working on them very much anymore but his lab in particular is pretty much from what I understand all working with these induced pluripotent stem cells now but there are other people who are still plugging away with the embryonic stem cells because as I said there really is that huge potential with them well somebody's going to probably make a lot of money for sure I don't know about a lot of people aren't going to live side of it as I said a lot of what I'm talking about here some day could actually decrease the number of clinical trials that need to be done or the earlier stage clinical trials that need to be done so probably fewer people you know may suffer as the result of something you know an early stage clinical trial or something oh yes yes yes yes yeah and I think you know one of the things that it doesn't make it right and there's a lot of work to be done in healthcare but I'm giving a presentation tomorrow where I'm talking about drug discovery and pharmaceutical companies it's a multi it costs them multi billions of dollars a year to to discover new drugs and put new drugs in the pipeline so part of that part of that huge expense is related to I think you know I don't know this personally but is related to their wanting to be able to recoup some of the investment they put into developing these drugs oh that's right and they know that they've only got x number of years to recoup that because eventually it goes generic and then anybody can make it so they've got to recoup that expense while they can so that's part of it the greed certainly plays a role yeah and then there are these drugs that are really only they're almost like designer drugs there's really only a small number of people who can benefit from them and so again if you're spending you know multi millions of dollars to develop that drug and you've got a thousand patients across the country who are going to be able to use that I mean being a scientist I would say do I not develop that drug or do I develop it and at least try to make it available to people I don't know but it's a it's a point well taken and of course one of the things that I've been thinking about too with this other presentation is access to drugs so does everybody have access to that seven thousand dollar drug who needs it so that's another piece of that one that's I'm teaching a class tomorrow I really appreciate you all coming and I I'm thrilled that you had questions for me I enjoyed it a lot thank you