| 1 | Protocol Labs | Brain Rejuvenation by Partial Cellular Reprogramming | Yuri Deigin | 1850 | 68 | 5 | 69.1 | positive | 58:59 | welcome everybody to this session my name is Yuri denan I'm the CEO of Youth Biotherapeutics and today I'd like to tell you about partial reprogramming and uh in particular its application to the brain which is what precisely we're doing at youth bio and uh um just a few words about who I am just so you know um I've been a drug developer for over 15 years and I've been a longevity activist for over a decade and uh I'm one of the earliest proponents of partial reprogramming as you can see on the slide I founded the first company dedicated to partial reprogramming in 2017 and uh to translate partial reprogramming into therapies unfortunately I was a bit too early investors thought I was kind of crazy trying to uh activate yamanaka factors in the brain uh but uh thankfully other people came into uh the area like people like David Sinclair and investors got much more comfortable and people like Jeff Bezos or us Miler poured like $3 billion into partial reprogramming companies and so in 2020 I started use bio where our Focus from the very beginning was on the brain and uh let me just uh say a few words about why I'm so bullish about partial reprogramming and then I'll dive deeper exactly what partial reprogramming is for those of you who don't know but the next few slides are just like a movie trailer preview of what's to come in my presentation and why par programming is so awesome and it's it's awesome because it has the potential to completely revolutionize medicine and if in 2017 I was one of the few to recognize this potential as I mentioned now there's a lot more people like Joe Bezos who've also recognized it and poured billions of dollars into it I mentioned Alo slabs which is probably the most most known example there's also Sam Alman who financed retr with like $180 million there's Brian Armstrong of coinbase he's financing a new limit with $100 million so partial reprogramming now is is really taking off and for good reason because reprogramming has been shown to rejuvenate cells fully rejuvenate cells on the cellular level and amarate homeworks of aging and so it's been demonstrated to be effective in many different cell types and different cell types have like different diseases associated with it so there's like dozens and dozens of diseases in which partial reprogramming can have potentially therapeutic benefit so collectively this has the potential to be like a trillion dollar field if these therapies are indeed proven to be effective and safe and go on the market and it all started with this paper this 2016 paper by ampo all out of the sulk Institute which demonstrated that parure e programming can extend lifespan by up to 50% in Pro mice these mice are fast aging mice but yet this is a very compelling result and it showed that Not only was their lifespan extended it also showed they had many any other benefits relative to home marks of Aging or relative to their his tissue histology basically it made tissues look younger or at least physiologically younger and also more importantly recently there is a result in normal mice uh completely normal mice not transgenic animals with a gene therapy approach who've been shown to extend lifespan bip partial reprogramming the previous model was a transgenic animal so it's it's really complicated to translate this into humans because we're are already kind of formed without the Amica factors so we need a gene therapy approach and this paper kind of recapitulated what we would expect from a therapeutic standpoint it had a gene therapy with OS delivered to these old mice and that extended their lifespan by not much but as a proof of concept showing that it's possible to use par programming to extend lifespan of normal animals and as I said this is a preview I'll go deeper into each of these things later on in the presentation uh but also besides extending lifespan partial reprogramming has been demonstrated to be effective in many different models of disease I mentioned theoretically it could be a trillion dollar market because by now I think there's been like a dozen studies in different disease models showing some sort of therapeutic benefits and this slide is about Alzheimer's which is very dear to my heart and this is what we're doing at youth bio showing that parure programming can have beneficial effects beneficial therapeutic effects in a mouse model of Alzheimer's and I was very happy to see this paper this is not by our group but we're also doing of course Alzheimer's research and this essentially validated the findings that we observed in our studies of our Gene Therapies in our Alzheimer's Mouse model so now that you're hopefully interested to hear more about partial reprogramming let me give it a proper introduction but for a proper introduction of course we need to talk about why is it that we need to rejuvenate things in the first place and of course this is because of Aging so we need to talk about aging but before we do let me just point out uh kind of an interesting Paradox that we've been discussing here in the past few days that when you ask people like the general public do they think we should be eradicating cancer and everybody's like yeah yeah we should cure cancer and you ask them what about Alzheimer's everybody yeah yeah we should cure Alzheimer's and if you ask them pretty much about any disease they all think yeah diseases need to be cured we should eradicate all diseases and then if you ask them okay let's imagine we've eradicated all disease and also figure out how to keep you young for as long as you want how long would you like to live in that scenario and people still say that oh maybe just 100 years and to me this is mindboggling like why do you want to have some sort of external externality determine how long you live shouldn't that be your choice shouldn't you live you know for as long as you want rather than have something externally determin that and it's funny that even within edes moral the mark Haman did a poll only about a quarter people attending this very Progressive you know Gathering of you know hopefully very smart people only about a quarter of those people say they would want to live in indefinitely and others still want some sort of like external uh expiration they put on them so um I I find that mindboggling because basically you know this ability this option to to determine ourselves the control of our biology including how long we want to live I think it's so valuable that we should all be you know trying to get it and support the research that is trying to um uh give this option to everybody in the world and I think the reason why people uh don't really they think they don't want it is just because collectively Humanity has this sort of Stockholm syndrome when it comes to aging and death and I think it's is a textbook case of learned helplessness and I think Aubrey deg gr put it really well he said that we all grew up with the idea that aging is inevitable and so we rationalize that okay if it's in inevitable even if it's really bad we can't do anything about it so let's just accept it and pretend that we didn't really want it in the first place like oh okay you know it's it's impossible so I don't even want to live for as long as I want but of course thankfully science and technology has been kind of pushing away from like pushing on death and aging for the past you know many many years including extending our lifespan for example in the past like 100 plus years we've extended the median lifespan from about 50ish to like 80ish so that's a 30-year increase in median lifespan and there is still room to grow because the oldest humans are known to live to about like 120 just a bit Les a bit less so there's still a lot of room to grow just within the known human lifespan between 80 and 120 and also this is just kind of known biology but of course there's this X Factor U that can potentially extend it much farther Beyond 120 that has to do with current you know research genetic engineering and the novel things that will eventually become modern medicine which they haven't yet but this is once they do this has the potential to extend our lifespan much greater because right now we finally we collectively as Humanity finally have the tools to modify our biology in you know ways we couldn't imagine maybe just a few decades ago so it's it's I think basically what I'm trying to say it's time to kind of get away from our learned helplessness and at least put ourselves much much more um Higher Goals of what we want to do with our health and our biology and of course the inspiration from to to the previous slide that we can extend our lifespan much more significantly stems from the observations that in nature there're animals who live much much longer than humans do by like 100 200 or even 300 years they live longer than us so with the proper tools that are disposable like genetic engineering we can potentially you know reach or even surpass those same lifespans because we know that even some mammals they live for over 200 years so I don't think it's you know out of the realm of possibility of figuring out the mechanism behind that and also implementing them within ourselves and besides mammals there's green shark that's known to live over 400 years some estimates even say over 500 years and so the problem that we're trying to solve at youth bio and the rest of the longevity field is the aging process itself we're just trying to do something about well about those kind of later years marked by bad health and suffering and initially would like to figure out how to slow down the aging process extend the healthy years of Our Lives then learning to stop a all together just to maybe even prevent ever having to suffer from the diseases of aging and ideally develop ways to reverse aging for those people who kind of have already entered the not so healthy years of Our Lives to bring them back into good health and allow them to um enjoy that good health indefinitely and so this is why we're called youth bio we want to extend not just Health span or lifespan we want to extend your youth span which is the most enjoyable and most happy and most healthy time of our lives and so one possible solution of how we can do this is cellular reprogramming because on the cellular level reprogramming has been shown to rejuvenate cells and accomplish pretty much all of the things that I was talking about on the previous slide including ameliorating all cellular homeworks of Aging that are listed on this diagram I have a pointer oh no I don't um but basically this diagram shows that the reprogramming process reverses all the homeworks of Aging that are known to occur at the cellular level and so now the biggest challenge for our field is to translate this these results from the cellular level to the organismal level and enjoy the benefits of Rejuvenation in our already adult organisms and just before we go go deeper into reprogramming just like let me briefly talk about what aging is and actually there's no consensus in the field on people scientists that study aging don't completely agree even on what it is of course there's Hallmarks of aging and I think we actually all of us know it when we see it like we can very well tell apart an old person from a young person but then having a precise definition scientific definition of course is a little more complex than that but you know obviously aging involves the worsening of our ability to maintain homeostasis and it's known to be associated with all sorts of Hallmarks listed on the slide and really the the biggest problem with aging is that it kills us and the fact that it it not only that the rate at which it kills us or the risk at which it kills us grows exponentially with age and so for like since about age 10 the risk of dying doubles every eight years and if for a 20-year older annual risk of death so risk of dying within one year is about 1,000 which is very low just imagine if we are able to freeze aging that such a person would be like mathematically expected to live a thousand years but then for a 60-year-old it's already one in 100 and for an 80-year-old the risk of dying within one year is one and 10 so you can see the exponential increase in that risk and before killing us of course aging makes us suffer with this arenol of unpleasant diseases all of which also increased exponentially with age of course the two biggest killers are heart disease and cancer I'm sure most of you know this and there are a few other Pleasant things like dementia which you know also not not a fun thing to have um and the second biggest problem with aging is that besides actually killing us it uh starts so early the process of Aging starts so early I think we barely get to enjoy our you know fully grown bodies until and they when they start falling apart at like age 40 basically and the pace of this falling apart is is infuriatingly quick so of course The Logical question then is why does aging happen at all and as I mentioned scientists can't even agree on what aging is so obviously there's no consensus of on why aging happens and some people like John and be may think that aging is completely random other people kind of on the end of the spectrum think aging is programmed me and there's I think then there's this Continuum between the two poles something that might be like an accidental program and obviously nobody's denying that there are some stochastic random changes with with aging the question is what plays a bigger role and what allows the stochastic events to eventually start accumulating as damage and why doesn't that happen for example in the first 20 years of Our Lives I won't get into like the debates on the uh what exactly causes aging we can just uh for now for just for the benefits of of this presentation look at empirical facts and kind of draw conclusions in terms of what things we can modulate and what things matter more and what things matter less look at just kind of the Animal Kingdom and inform our opinion on what we think are more important or less important aspects of aging and I think epigenetics is a more important aspect of Aging just kind of like a preview and the next few slides we'll try to make that point and of course this slide uh I think the main takeaway is that aging is just not Universal there's so much variation in lifespans and so like rates of Aging in the animal kingdom some species live just for a few days other species live for like a thousands of years and even within the mamalian kingdom among mammals the variation is like two orders of magnitude Mount lives 2 years whale 200 and so um but even within much closely related species than a mouse and a whale like for example this genus of rock fishes which are you know very similar evolutionarily related species on kind of their their philogyny they have huge variation in lifespan between like some some rock fishes live just 10 years and others live for over 200 years and it's not just two species it's a continue of 50 different species with kind of very smooth increase from like 12 years to 205 years between them so again aging within like I think on the power of evolution to really adapt to particular eological Niche aging can be varied very you know easily at least on an evolutionary time scale and I already made it the point that aging is not Universal but this slide tries to show just how variable the patterns are in the animal kingdom and to me this means that there's no single fundamental like physical law like say some people say oh it's the second law of Thermodynamics entropy has to increase but actually when it comes to the Aging of biological systems that's obviously not why we age and of course being open systems we can take in energy and matter and decrease entropy and so there has to be a aging has to be a biological phenomenon rather than just a phenomenon of physics and clearly aging is under genetic control uh because you know DNA determines how long a species lives and of course there's some variation between individuals there could be also some inputs uh based on environment but all of this happens within the confines of the life history encoded by genomes and um this is I mean we understand this from a basic level that's everything encoded in the DNA that then drives the morpholog morphology and the subsequent life history of a given species and the good news that genetically prolonging lifespan might not require massive genetic manipulation as kind of two quick examples show here in in mice just a single Gene actual knockout or knockdown can greatly extend lifespan and by almost like 70% and in nematodes a single Gene knockout increased the lifespan by 10 times so obviously with simple genetic manipulations it's possible that we can greatly uh increase lifespans and also artificial selection can ex uh greatly extend lifespan as well this is a famous Michael Rose experiment in fruit flies which initially increased lifespan in those flies by like 30% they continued running this experiment for like many many years years and ultimately they claim to have extended lifespan of these fruit flies with just like you know random mutation but artificial selection by up to seven times which shows that on a very very small evolutionary time scales like our time scales you can greatly increase lifespan and so to me this shows that there's a lot of potential for lifespan increase with genetic and I'll make the case later epigenetic modulation and so uh the next few observations are devoted to this hypothesis that it's also epigenetic modulation that can greatly vary lifespan on a level of a single individual and of course this has important implications for us because I think we all want to also be able to extend our lifespan rather than kind of live with a happy thought that eventually Evolution might extend human lifespan sometime in the future I think we actually want to get to live to see that they are s and so the next few observations that kind summarized on this slide I'll just quickly go into some detail about them why I think there's a strong case that there's epigenetic control of Aging as well and just briefly for those of you who might have not heard what epigenetics is this slide tries to summarize it basically epigenetics is control of gene expression so we are a multicellular organism we have 200 different cell types but of course each cell has the identical copy of DNA and so for each different cell type we the cell needs to have a certain set of genes on and off and so the mechanisms that control this are called epigenetic mechanisms and there's various different mechanisms I won't get into like exactly each once basically we need we need this system of control of gene expression and this is what we call epigenetics and also within aging we observe that these epigenetic changes happen during our aging with some genes kind of going down in the volume there's also it's not just the binary on or off there's also like a volume knob and some genes get silenced other genes get upregulated and these mechanisms are uh being observed to be play an important role in aging and let me just now share a few more observations from nature that I think show that aging could be under epigenetic control and of course the most clear example of this is social animals where you have identical DNA in the same kind of uh twins essentially determining very different lifespan if uh this individual ends up being a queen it lives by you know several times or sometimes in order of magnet longer than the same individuals with the same DNA but who went to the worker path and an even more extreme disparity is observed in ants their ant Queen lives for like up to 30 years and worker ants live like just one or two years and yeah like when I first found found out about examples my eyes were like enlarged just like yours I'm like holy as a small insect that lives longer than a horse or like twice as long as a dog this is like incredible that's probably longer than most Maman species 30 years and U yeah this I like wow uh I really like this example because previous examples of course they were based on like the social role of the insect and some people argue that essentially like two different programs in the same DNA that just like at Birth you go One path or another that determines your lifespan but in this case this shows that epigenetics can influence the lifespan even in the context of a single individual and it can actually be reprogrammed uh epigenetically and have a much longer lifespan in this case if this an it it's born as a worker but then under some uh circumstances in the colony if if the queen dies workers can become breeders and in that case their lifespan is significantly extended and so this to me shows again the power of epigenetics to modulate and change the fate and lifespan of an already formed individual and here's an example another example of extreme variation in lifespan brought about by epigenetics and I like it even more because mon butterflies they do not have different social roles and the only thing that determines how long they will live is the season in which they're born if they're born in the summer they live very short like about a month but if they're born in the fall then they need to migrate down to Mexico for the winter and basically in that case they live for like nine months and so this is again an example how epigenetics can greatly modulate lifespan of the species and we even observed this in some mammals because there's this rodent in Montana that have a similar pattern that if they're born in the spring then they sexually mature within the same year they breed and they die by the end of the year but if they're born in the fall then their development is put on pause and they actually sexually mature after the winter and so this also greatly extends their lifespan and the previous examples they were like about insects or animals of course we're much more interested in ourselves humans and while we don't have as clear examples of epigenetics playing a role in our aging but now we have Le circumstantial evidence that there is also epigenetic control of our lifespan thanks to these epigenetic clocks that have been discovered about a decade ago or even more than a decade ago by now and they show that uh there is this clock that ticks in our cells even sometimes very different cells this slide shows different tissues which show that this clock is synchronized between cells as different as a neuron and a blood cell and yet they show the same epigenetic time and so if you take a cell from an individual you can actually tell how old that individual is without knowing anything about them uh and so this shows that there is a some sort of epigenetic process some people like myself argue epigenetic program running that with aging modulates the epigenetics of very very different cells and another observation about these epigenetic clocks that they actually take slower in animals that undergo known interventions no interventions known to extend lifespan or slow down aging so basically they show that these clocks are kind of causitive and not just correlative so if you use an intervention to slow down aging basically this will be reflected in the clocks and if if you weren't yet convinced that epigenetics plays a key role in aging I hope the maybe next few slides will maybe convince you because uh these ones present uh the latest discovery that not only do all mammals have these epigenetic clocks this is worked by Steve horv and and his colleagues but you can actually build a panaman epigenetic clock that has the same underlying sites in the genome so basically it's like a a conserved epigenetic clock that reuses the same sites in the genome between very different species and the only difference between those clocks is of course the speed with which they tick so they use the same sides in the genome and the only difference is the speed with which those sides in the genome change over age so basically you could say that a mouse epigenetic clock just based on built on this cpgs just uh is ticking 30 times quicker than a human it's still the same same kind of epigenetic program it just ticks faster and I think this is a compelling evidence that there's some underlying epigenic program running with aging and so also these clocks have been shown to be very accurate across pretty much all mammals regardless if they're shortlived or long lived and to me also another convincing observation is that the clocks they were built based on adult tissues and yet when they observe the epigenetic timing in uh tissues from like embryos or development developing um uh individuals they show that the clocks recapitulate the development process even embryogenesis but the only difference being that that process is exponentially faster so basically uh and we also see this kind of remarkable conservation among species essentially we see that pretty much in all mammals the first 10% of our life history is spent on development according to these epigenic clocks which moves at an exponential ually quicker Pace than the the rest the other 90% of our life history and so this I think is this kind of ultimate evidence of a conserved eptic program running with at least the Maman genomes that determines the Aging life history or the Aging trajectory of our species and so the B the the basic kind of variable in this program is just the speed at which the clock ticks so like mentioned the mouse clock just moves 30% uh 30 times quicker than a human clock okay enough with like theoretical epigenetic uh questions the I think the question that we're all kind of wondering about is if aging is under epigenetic control can we actually do something about it can we reverse it of course epigenetics is reversible so it's U The Logical inference to make is that can we actually use epigenic to reverse aging and obviously in nature we see Rejuvenation happen all the time and uh it just seems to be reserved for reproduction in fact I think it's a requirement for reproduction without Rejuvenation post reproduction we wouldn't be here as I think there would be some sort of accumulation of of damage from one generation to the next but thankfully after fertilization the damage gets cleared and we have evidence of this from many different species showing that there is active clearance of damage there's active Rejuvenation that is tied to reproduction Even in our organisms as simple as yeast which are just you know unicellular single cellular organism which like a special case they can reproduce both sexually and asexually they can just do cloning and if they do cloning asexual reproduction they age but as soon as they're forced to reproduce sexually through like gametogenesis process they are rejuvenated and so this observation seems to be uh very again evolutionarily conserved about this rejuvenation to reproduction and it's been observed you know also to be the case in mice that also clear damage after fertilization in nematode worms by this was shown by Sy Kenyon team they have the same process of damage clearance in sexual reproduction in frogs also similar observation there's active Rejuvenation happening after fertilization and and a very interesting observation kind of Shifting Gears again to epigenetics is that what actually happens when people what happens after fertilization when people look at epigene clock is that the Rejuvenation event is not immediate it doesn't happen right after fertilization but it actually reaches a minimum at about day 10 if we talking mice which is coincides with gastrulation and so this implies that there is some sort of active rejuvenating program tied to reproduction that actually takes some time to work its magic and rejuven cells and uh this was a paper by the gladish group this is another paper by the gladish group but by Alex strap that also confirmed the same findings but at a single cell resolution basically showing that there's an active rejuvenating program happening after fertilization which reaches the minimum during gastr relation and another paper from the same group but looking at frogs showing that in frogs also the epigenetic epigenetic age reaches a minimum at gastrulation okay now let's talk about reprogramming with like this whole Preamble of what actually happens during during aging from epigenetic standpoint now we can talk about what we can do about it and how we can modulate epigenetics and just historically uh I think we should start with the Dogma that was prevalent in like the 19 or at least formulated in 1940s and was prevalent until uh very recently that uh cell differentiation is a one-way process basically everything starts as an embryo and then cells roll down this landscape and differentiate into eventually like a neuron or a skin cell but they can never come back up that was the Dogma that was called the wton landscape formulated by Conor wton and everything pointed that there's some sort of like irreversibility to this process however very quickly just 20 years later that Dogma was uh at least the first time proven wrong by John giren who showed you can actually take a nucleus from a skin cell put it into u a an egg cell we're talking frogs here and you can generate a whole complete organism and this refuted the the notion that the skin cell somehow loses the DNA that necessary to form other cell types and so this was kind of the first instance of uh at least showing some doubt in the Wasington dogma and it was again repeated in the 1960 1990s 96 which famous Dolly the sheep cloning experiment which is essentially a repeat of the John giren experiment from like 30 years before but it again showed that actually you know there there is some potential for reversibility and the this was conclusively proven in 2006 by sh yaka that not only showed that it's possible he showed how to do it he showed that if you induce these four factors transcription factors that are later came to be known yaka factors then you can take any cell all the way back to this embryonic ground state and so after this discovery for which he got a Nobel Prize in 2012 and of course Jord Gorden also got a Nobel Prize they shared the Nobel Prize they updated epic lens came became essentially bidirectional it showed that you can move up and down and actually you can move across you can take a skin cell and trans differentiated it into a neuron without actually needing to go to the ground state and with that finally uh after this discovery we have entered the possibility of how to affect this epigenetic Rejuvenation that I've been kind of hinting or talking about in the previous few slides and the observation that really set people in motion trying to accomplish it was that during reprogramming the cells are not only epigenetically rejuvenated they don't only go to the ground state based on like development or differentiation they're also physiologically rejuvenated like I mentioned the Hallmarks of Aging in in the first few slides and the first observation came from Jean maret team and inserm that you can take uh like cells from very old people you reprogram them into embrionic plottin stem cells and then you reprogram them back into fiber blasts and those fiber blasts are fully rejuvenated it's as if they were from very young people and so this uh then got researchers looking at other homeworks of Aging repeating the these experiment or doing new experiments and this is what then formed the basis of this diagram essentially summarizing many different uh um papers and a lot of research showing that all cellular Hallmarks are ameliorated by the reprogramming process and the next logical question for the field of longevity was of course can we capture this rejuvenating effects of reprogramming and use it in V use it for rejuvenating adult organisms and the the first attempt at this wasn't really successful it the but the first ever group to try this was monal sanos group from Spain in 2013 what they did is they basically created a transgenic Mouse model in which these yanaka factors were in every cell but they were silent until you actually induced them and then they tried inducing them in adult mice and they didn't really see a positive effect basically they saw that those mice died like weeks after they started the induction of the of the yaka factors and so the title of their paper wasn't very reassuring it was like uh reprogramming in Vivo produces teratomas and ipf cells with 30 potency features teromas are of course like tumors and uh I I don't think anybody reading that paper's even title would be you know very inspired to start doing par reprogram uh but thankfully Alejandra campus group was not deterred and and they actually figured out how to use partial reprogramming in Vivo safely to get just the positive effects without the negative effects and the genius of ampo and his colleagues were that you have to do reprogramming for very short durations and that's what came to be known as partial reprogramming because if you allow reprogramming to proceed too far you get side effects that eventually kill the mice which is what you don't want but if you induce yanaka factors for just like a couple of days you get red rejuvenating effects and that what led to this liman extension by up to 50% if you compare it to the first control group or 30% if you compare it to the third control group but basically that was the therapeutic result that they observed and even visually like people who work with mice can can tell a difference that like the control group has the sky phosis this curvature of the spine that is anaging hmark whereas the treated Mouse does not but more importantly not just from appearance but like on the biomar level the level of tissues the mice that were treated by yanaka factors were younger according to these metrics they had fewer cin cells fewer DNA breaks uh their tissue hystology was better like there's four different tissues listed here skin spleen kidney stomach Etc and uh oh they had yeah even better hair and hair of course is a hair thinning and hair graying is a homework of Aging um and so this kind of summarizes why I am so bullish about partial reprograming basically because I think it works at precisely the level at which our biology happens it works on the cellular level and regardless of you know the Matrix and the uh things that happen around the cells ultimately all the signals have to be processed by the cell and the the cell really decides how old it is right if the Matrix tells the cell you're old if we intervene at the level of gene expression and say don't listen to The Matrix you're still young we upregulate the genes that you know are associated with the younger cell then really we can circumvent the external signaling not to say that I don't support other approaches like replacement I think there's a lot of potential Synergy and replacement is also a completely viable option but I think also think paral reprogram has a lot of potential because we can actually by changing the gene expression of the cell which what what par does we can circumvent uh the aging process and so I guess one of the next interesting question is how does par reprogram work what you know where does the magic come from and unfortunately the exact mechanisms are still unknown I mean we know how reprogramming works and again from like a very mechanistic standpoint that it opens up chromatin silences one set of genes regulates or starts expressing another set of genes and ultimately this leads the cell to this path to PL potency where it it starts expressing the genes associated with ploty but where exactly in that process the rejuvenating aspects happen we still don't know but uh let me just kind of share some of my some observations that and speculate on what I think might be happening that uh could explain the rejuvenating aspects of par reain and I guess the the first question is so what exactly do yamanaka factors do and I think a lot of people already know that yamanaka factors are the factors that are responsible for maintaining stemness in these embryonic stem cells but and they're also known to be these Pioneer transcription factors that are able to access closed chromatin and start opening it up but I think what's less known about yaka factors that they're also the factors that trigger this maternal to zygotic transition during renesis and I'm getting maybe a little bit deep into like embryology but this is the process where the maternal genome gets silenced in just a few days after fertilization and the Genome of the you know ultimate resulting organism starts being activated and so if you remember the yeah that starts in the blast stage and and basically continues in the gastrol estage and if you remember this paper from the gladish group that shows that embryonic age embryonic igen age reaches a minimum at this blastula stage uh I think Gast stage again I think there's a lot of um good reason to believe that there might be some overlap between the rejuvenating program that is normally activated during embryogenesis and basically what transcription factors IM Manaka factors also trigger in the early stages of the reprogramming process so basically maybe the same gene networks that are responsible for this Rejuvenation that we see during embryogenesis are being activated by the reprogramming process and um yeah and this I think this gives a new meaning to this fun quote about gastation that it's not birth marriage or death but gastrulation that is the most important time in your life because that's what rejuvenates you as an organism okay now just still in the question of how does partial reprograming work but Switching gears from like the hypothetical scenario to just the empirical observation we don't know it maybe exact mechanisms but we do know that partial reprogramming leads to Rejuvenation so in particular the we can see this Rejuvenation on the transcriptomic levels the levels of transcripts mRNA produced by by the cell we see that uh after partial reprogramming the pattern the gene expression pattern the transcriptomic pattern of the cell is shifted towards the pattern observed in younger cells of the cell of the same cell type and so this is one result showing this here's another study showing the same observation that you're rejuvenating cell at the transcriptomic level the level of mRNA and of course I previously showed that par program rejuvenates cells at the epigenetic level the level of epigenetic clocks and so also on the third level just a level of physiology there are also observations that partial reprogramming induces this physiological Rejuvenation improves tissues at at the physiological and histological levels that are in the cells that are partially reprogrammed and the question why this is possible why you know Rejuvenation is possible during the reprogramming process I think we're just lucky that the reprogramming process is gradual both in the changing of cell identity and in the rejuvenating aspect and this slide shows like the two trajectories one trajectory of silencing the genes responsible for like fiberblast identity and another slid showing rejuvenating re Rejuvenation the the blue line is the epigenetic age of the cell and we see that this is a gradual process basically that cells are gradually reprogrammed they gradually are moved in the direction of embryonic stem cells and they're gradually rejuvenated and so there is some point like a therapeutic window B basically where we haven't yet reached the point of no return where the cell can no longer be a fiber blast cannot no longer do the function of the skin cell and yet at this still by then the cell has already been rejuvenated so we can if we stick to this therapeutic window we can push the cell just enough in the direction of embrionic stem cell but not too far so it's still a fiberblast but it's a rejuvenated fiberblast at least according to this research that looked into rejuvenating process and genetic age that happens during reprogramming and so this is what essentially what we're trying to harness thanks to this gradual nature of reprogramming we can find this window of safe partial reprogramming where we get Rejuvenation but we don't yet get the risks associated with the cell stop stopping doing its job and uh just to address another kind of a frequent point of criticism that Skeptics of partial Reaper bring up they often bring up this uh well-known fact that in vitro when you reprogram cells in a Peter dish only a small percentage of cells end up being fully reprogrammed to this F potency most of the cells do not and they kind of point to this and say well if only a few cells ever get to full reprogramming then only a few cells will ever be rejuvenated in Vivo and it's never going to be efficient enough as a process to be used as a Rejuvenation therapy for an already foreign organism but those people who actually study uh invivo uh inv vitra reprogramming they know or they know at least now they know that the initial stages of reprogramming are ex uh exerted on all cells and this initial opening up of Chromatin that happens happens in all the cells that have yaka factors activated in them and it's just that in most cells what happens later is chromatin is recondensed and it seems to be an active process preventing cells from being reprogrammed but if you actually disable this active process as this paper show this is one of the hisone hone 3 k36 if you want the details but if you disable that process then all of the cells in the feature dish actually make it all the way to cotesy so this implies that actually all of the cells experience the all of the cells exper experience reprogramming and in particular the early stages of reprogramming which are associated with Rejuvenation so we can expect for iniva reprogramming the cells to pretty much all the cells in which we activate the reprogramming genes to be rejuvenated to some degree because they all experience the initial stages of reprogramming and so the applications of this are quite profound basically uh as I mentioned in the beginning the problem with the aging process is or one of the problems is that it's exponential in increasing our mortality risk and so if we're able to somehow slow down this exponential increase or ideally would like to stop it or even reverse it then as I mentioned the like a person in in their 60s has one and 100 chance of dying within a year which is for a 60-year-old is is actually not too bad if we're able to freeze the aging process and stop it right there then the 60-year-old person just with this uh aspect of reprogramming just stops the increase in mortality risk just mathematically could potentially expect to live another 100 years and if we're able to reverse of course the aging process which I think partial reprogramming like repeated partial reprogramming can accomplish then we can then even rejuvenate people and decrease their mortality risk and of course while that's the ultimate goal we haven't gotten there yet we're just making kind of First Steps in this direction but I think there has been many promising steps in that direction since the 2016 or Campa paper and just want to highlight some of them in the next few slides that I think are particularly compelling for example this step that show that even a single B of partial reprogram can extend lifespan including in progeric mice and normal mice this paper the many of you have seen it from David Sinclair's group this is the famous paper where they were able to restore Vision in mice with partial reprogramming uh another paper showed that partial reprograming can improve muscle reg regeneration after injury wound healing also I mentioned in the beginning there's like a dozen different disease areas in which partial reprograming has been shown to be therapeutically effective and these slides just quickly go through them just because we don't have enough time if we had to Deep dive deep into all of them we need a couple hours uh this study showed that you can improve spinal dis degeneration with param this study looked at long-term safety of parti reprogramming showed that even a 10th 10 month long protocol of inducing IM manactors is not only safe but also therapeutically beneficial this is the same paper just another slide showing the results that with yet 10 month long period of induction in mice it was safe this study already mentioned uh in the beginning as I said Skeptics of partial reprogramming have pointed to Wild type mice as being kind of next measuring stick by which part partial reprogramming has Effectiveness has to be measured and U uh basically they were saying that because we haven't yet seen a life extension in normal mice then maybe partial reprogramming Life Extensions is an artifact of pric mice but this paper out of rejuvenate bio showed that actually gene therapy approach can greatly increase uh lifespan in not greatly but can increase lifespan in in normal mice and also there's been uh a few unpublished results I just came from a conference where people were reporting unpublished results and they're again very very promising because there group showing the parain can improve the brain in Vivo uh liver function cardiac function hematop stem cells and t- cell function and also the David Sinclair's group is pursuing an indication in the eye this eye stroke indication for using a gene therapy based on partial rogain to go into the clinic and it might be the first group to get partial rogain into the clinic okay finally let's talk about brain Rejuvenation and uh there's been also a lot of uh exploration of partial reprogramming in the brain as well including by ourselves one of the earlier studies from an alanus group who's been a pioneer of partial programming as as I showed in 2013 they've continued looking into it and they showed that partial reprograming can improve memory on the object recognition test and this is a very cool result very recent result of 2024 paper by Ares group from Stanford showing that reprogramming partial reprogramming can increase or induce neurogenesis in Old mice like basically generation of Novel neurons in the hyppocampus of old mice which has been a very uh kind of controversial aspect do we get can we have neurogenesis in adult brains and with at least with partial reprogramming it seems that we can another brain reprogramming company uh reprogramming paper from rolfa goya's group in Argentina showing that if you deliver gene therapy into the hippocampus of old rats in this case you can inre increase their cognitive performance and this is uh very similar to what we've done at youth we've delivered a gene therapy into the hyppocampus of uh old mice and also Alzheimer's mice and we also see positive results and U rolag Goya group saw improvements in cognitive tests and also saw reduction in epigenetic age of the rats treated by partial reprogramming they also done a different study on female fertility where they injected female rats in the hypothalamus with partial reprograming therapies and they showed that after after inducing partial reprogramming in that brain region that has positive effects on female fertility and moving on to alzheimer's my personal passion and of course the therapeutic focus of Youth bio uh there's from the very beginning we had good reasons to believe that Alzheimer's is a good indication for partial reprograming mainly because Alzheimer's has a strong epigenetic component to its ethology to to to the way Alzheimer's happens and basically gene expression in the brain cells of Alzheimer's patients can could actually be can explain why the disease progression happens as if you might remember since epigenetic changes are reversible we can be at least with some confidence expect that if we reverse the gene pattern the pattern of gene expression in the neurons of Alzheimer's patients we can expect if maybe even a reversal definitely slowing down of Alzheimer's symptoms may maybe even a reversal of Alzheimer's symptoms this was the theory now we have evidence in practice that this indeed seems to be the case this is a study in Alzheimer's mouth bottle showing that you can epigenetically prevent Alzheimer's then this is actually the study from 2019 that was the main inspiration for the hypothesis I just outlined basically showing that you can epigenetically reverse Alzheimer's symptoms in in a mouth model and basically it show that epigenetic modulation can like not only prevent the symptoms but can reverse them and this was what made me very optimistic that in patients we can observe the same reversal of symptoms using epigenic modulation by partial reprogramming and uh this is the paper I I gave a preview in the beginning and it seems that we're running out of time but I was very happy to see this this is a 2023 late result basically validating the same observations that we had at youth bio that parti reprogramming in Mouse model of Alzheimer's disease can have beneficial effects beneficial therapeutic effects on Alzheimer's might Alzheimer's symptoms and also not only at the cognitive testing level but also at the level of biomarkers they show that you can have lower levels of bet amalo which is a key biomarker of Alzheimer's disease lower plaque burden in in these mice and also on the cognitive test of course those mice also showed better performance in those tests and this observ of this group validate our observations which were very similar we saw a reduction bet amalo and we saw an improvement in cognitive tests in the in the mice and I briefly wanted to go over our results but it seems that I have only about five minutes but um basically our our main approach was our main tenant behind youp is that we need to be cell typ specific that uh you have to have specificity in terms of triggering partial reprogramming in in different cell types and this was validated by Alandra Campo who's if you remember was the pioneer of partial reprogramming and uh he's also our collaborator but he showed that if you avoid the liver and the small intestine you can push reprogramming for up to 10 days of consecutive expression of reprogramming factors and the all of mice survive but if you don't if you keep uh uh reprogramming the liver in the small intestine then the mice start dying after day four and basically this necessitates the cell type specific approach to reprogramming that you have to avoid certain tissues and this means that from our standpoint we can be also targeted in the cells that we induce partial reprograming in with the U different cell types listed here and of course neuronal cell types are our first priority with Alzheimer's being the first indication and relative to other companies we're already finished for animal studies so we're quite uh far ahead of our uh peers in terms of getting to the clinic and getting to clinical validation of param our first indication is Alzheimer's disease and there's I already mentioned there's good reasons from a scientific standpoint there's good reasons from regulatory standpoint why Alzheimer's disease is a good indication for Alzheimer's and our first animal study was as a proof of concept to show that we can deliver our therapeutic constructs to the brain and activate them in brain and get the expression of these factors in the brain and once we validated that with we went into three different disease models with Alzheimer's pereria and age related cognitive decline being the three models and we saw positive results in in those tests and I'm getting the signal that we're getting short on time and but basically yeah switching kind our Focus from the past to the Future the important factors in translating partial reprogramming they're listed on this slide and I think one of the main aspects is delivery and this is really the the the last interesting aspect of the presentation that I'll go into because a lot of people think delivery to the brain is a like insurmountable challenge but actually there's a lot of precedent in Parkinson's and gen already actually talked about this in Direct Delivery of therapies to the brain including cell therapies and Gene therapies and this slide lists like a dozen different Gene therapies that have been directly delivered to the brains of Alzheimer's patients by direct injection into substantial neiger and so uh also this has been shown in Alzheimer's disease as well that you can deliver into the hippocampus or Le very close to the hippocampus gene therapy and this was a 2013 study which then they had a follow up like 7even years later showing that the patients that had this injection into their brain had sustainable expression of the delivered construct for like up to seven years which makes me very optimistic that if our constructs that we deliver to the brain can also be expected to be very long lasting and there this is another paper showing the same uh precedent of Direct Delivery into the brain uh as I mentioned this just said that's the precedent that this delivery is possible but of course uh invasive delivery is is not great if we can avoid sticking inle into patient brain we should and for that there's now this concept of ultrasound guided delivery where it's a non-invasive method of getting things to the brain and this table lists like many different different Mouse models of diseases in which this approach has been tried and Beyond Mouse models it was also demonstrated in patients already this was the Toronto uh sick kids U Hospital study that showed that you can have successful delivery into the brain of pediatric patients using ultrasound guided delivery and I won't get into this slide just for the interest of time but basically future directions of partial reprogramming that are listed here uh I think we're well on our way of finding finding Noble factors some companies are dedicated to finding Noble factors that are not as risky as IM Manaka factors new limit shift bio their main mission is to find new factors and I think we'll need tissue specific and cell type specific factors that will be most effective in a given cell type and for that you also need cell type specific delivery mechanism which I think the field is also exploring and uh so in closing I just want to say that I'm very optimistic that uh both par reprogramming and brain Rejuvenation by par reprogramming will get to the clinic very soon and I just want to close with this quote from Dr b w after they published the seminal ampa paper with careful modulation aging might be reversed and I believe that with par programing we're well on our way to figuring out just how to reverse the aging process thank you very much and uh | ↗ |