| 1 | Longevity Summit Dublin | Rejuvenation Through Cellular Reprogramming- Yuri Deigin at Longevity ... | 2615 | 84 | 5 | 65.8 | positive | 31:21 | the next um speaker Yuri Degen entrepreneur and biotech expert who is now all right here we go yeah who is now the CEO of um youth Biotherapeutics specializing on genetical programming tissue specific in Vivo thank you so much for being here thank you it's my pleasure I guess today I won't be talking about my company or pitching anything uh I'll just talk about some fundamental biology aging biology that uh I I'm fascinated by and I actually as I was introduced as a kind of reprogramming guy before I became a reprogramming guy I was a person very interested in germline Rejuvenation and it's germline Rejuvenation that ultimately drove me to reprogramming once reprogramming showed its great potential to rejuvenate cells essentially ameliorate all cellular homeworks and also in Vivo produce Rejuvenation and live extension but um to uh oh there we go to to dive into the processes that basically make the germline immortal uh I think it's it's very illiter illustrative for ourselves and for uh us as an aging field to see What mechanisms already exist in nature that produce Rejuvenation and germline being a prime example of these mechanisms because all of us here can trace our ancestry back three and a half billion years ago to our common ancestor and this is actually our all right there we go our genealogical tree dating back all the way back to three and a half billion years ago to our common ancestor and it's fascinating that all of us here have a unbreakable line of successful regenerating events to that point in time and so the the interesting question I think from a very early stage in the field of aging biology was what exactly happens to the germline to enable us to enable it to have this Rejuvenation and one of the first questions was maybe germline is somehow prevented from accumulating damage in the first place but I think then later on indications were that it's not exactly the case and there might be actual active mechanisms of damage clearance and by now basically this presentation is all about examples of such active mechanisms of damage clearance that hopefully we can repurpose for ourselves because in the case of the germline they're reserved for reproduction for sexual reproduction when genes decided it's beneficial to activate these mechanisms but for some reason they decided that in the context of an already formed adult organism these mechanisms need not apply but for ourselves we're very selfish we'd like to kind of hack our genes and and hack our biology to use these mechanisms to Keep Us Alive rather than successive generations and so today I'll show some examples of What mechanisms we have now learned we collectively as a field have now learned are responsible for Rejuvenation in germline cells and then what we can do to actually repurpose them for our ourselves in somatic cells in cells of an already formed organism and so as I said uh one of the questions early on was is there some sort of privileged uh do journalists are protected from Aging in the first place and the answer to that is no there is accumulated damage uh in germline cells as well and while there is some maybe some degree of this kind of protection from aging damage still accumulates in germline cells and in the context of mammals for example you know our egg cells are the same age as the mother because they get formed when the mother is still an embryo and they show a pattern of accumulated damage which after fertilization is actually actively cleared and so some examples from other organisms also show this highly conserved evolutionary mechanism of clearing damage when sexual reproduction takes place and there's also this this question that's been asked before are germline cells Protected Their evidence from experiments shown here kind of summarize here in the slides have shown that germline cells are actually not actively protected from accumulating this damage is already already mentioned and so today just want to show several examples from several species kind of progressively from the farthest away from us to the closest yeast farthest and the closest being the mice that there is this active mechanism of Rejuvenation in the germline cells so starting from yeast uh just want to highlight this work by Elton who used to work in the Angelic Ammons Lab at MIT unfortunately Angelica passed away several years ago now Elgin has her own lab in Berkeley and so these experiments were done by them together many years ago and so in yeast there's uh two sorts of lifespans there's chronological Iceland and replica replicative lifespan and so in yeast they notice that this active process of damage clearance only is reserved for sexual reproduction for gametogenesis or sporulation which induces gametogenesis and so this work is based upon this concept of replicative lifespan which gets reset by this gametogenesis process and so the key findings by unal and Ammon were that it is the sporulation process that is reserved for this sexual reproduction that induces reset not only reduces reset of replicative lifespan but also active Rejuvenation and clearance of damage that has been accumulated in the cell uh previously and of course yeast are a special case because they're a single cellular organisms which is kind of both the somatic cell and the gamete depending on the context and all the damage you can relating within the single cell has to be removed during the the sexual reproduction process to to induce this Rejuvenation event and so they Dove deep into the mechanisms of this damage clearance and they show that there is active clearance of carbonylight proteins Advanced glycation and products extra bosomal circles that are all examples of damage accumulating in yeast during kind of vegetative growth non-sexual reproduction and then if sporulation is induced if the sexual reproduction is induced then all of those examples of damage get cleared and yeast get essentially have reset their reproductive lifespan and this is their experimental design uh just very simply they tracked various yeast cells both old ones and young ones and then they induce sporulation in both old cells and young cells and then looked into whether they were able to reset lifespan whether there was any discernible difference between the old cell and the young cell after the sporulation event and weather damage was cleared by this sporulation event this gametogenesis induction of sexual reproduction and so these slides basically go into a little more detail on what I already said they've observed they've observed that sporulation resets live spending yeast this repetitive lifespan the old uh modern cells the red line normally have only on average five divisions left in their lifespan in in their experiment while young cells have about 18 medium number of cell divisions in the reperative lifespan but if sporulation is induced both old former old and young yeast cells have a new kind of lease on life new counter of 18 cell divisions before they die and so this has shown that sporulation does reset replicative lifespan in yeast and then also they looked into the damage that gets accumulated during the lifetime of yeast cells and they also demonstrated that it is actively cleared carbonylated proteins which is a form of damage they showed that it's during Vegeta vegetative growth non-sexual growth they get accumulated but after sporulation after sexual reproduction they are fully cleared and this is just another slide with more information on on their procedure where they track down different aspects of these carbonylated proteins just basically to show that they have robust data for for the claims that they're making that carbonyl proteins are fully cleared by the gametogenesis process also another aspect of Aging Hallmark of Aging in yeast are these extra ribosomal Circles of uh our DNA which get kind of accumulated in in the cell and basically are a homework of Aging after fertilization uh sorry after gametogenesis these are DNA circles are expunged and nuclear nuclearly morphology is normalized by again the gametogenesis process so this is another example of damage that gets actively cleared by this correlation process and while an Old Mother cell might exhibit many of these extra ribosomal circles uh after extra chromosomal circuits sorry ribosomal extra chromosomal circles after sporulation event these circles are cleared and then they dove into what exactly is needed in terms of the mechanism to enable this Rejuvenation they were asking is it meiosis that is responsible for Rejuvenation that we observe in east or maybe it's you know dilution during meiosis because normally a Mother cell gets divided into four daughter tetrads during speculation maybe there's some sort of dilution that happens from one Mother cell that partitions the damage into the four daughter cells but uh in in a nutshell the answer they arrive to is no meiosis is not the deciding factor it's not the replication of DNA sorry it's not the division of the cell into four tetrads and the dilution of damage that is responsible for the gametogenesis process for the clearance of damage associated with the gametogenesis process and so they've tracked the levels of damage during the meiosis process as shown here and they they show that until kind of the final stage of sporulation even when you have the tetrad already formed for different daughter cells you still have high levels of these carbonylated proteins as an example which get cleared only after in the final stages of the the sporulation moreover if you actually disable meiosis which you can do in in these cells there's some strains where you can either in this example instead of the four daughter cells instead of two division two successive divisions you get only one division so you get two daughter cells in this case it's still uh cells get fully rejuvenated they in terms of reproductive lifespan they still get restored to full potential and finally even if you fully disable meiosis basically if you maintain the same cell the same single cell as the mother cell ends up being the daughter cell so there's nothing to dilute I mean there's no dilution because all the damage stays within the same cell even in that case use observe Rejuvenation clearance of damage and reset of replicative lifespan so all together that shows that biosis itself the process of meiosis crossing over or doubling of the DNA is not what restores the morphology and the uh of say our DNA circles and clears the damage so it could be connected to meiosis meiosis might be inducing this kind of system of Rejuvenation that triggers all of this clearance of damage but meiosis itself the the divisions that happens during meiosis DNA divisions is not what causes the the damage to be cleared and they conclude with the dilution not being the key factor driving the Rejuvenation of yeast cells during sexual reproduction basically what they observed in in their work argues against dilution but for active damage clearance mechanisms in yeast during sexual reproduction and this is actually what we see time and time again time and time again in other species other animals other examples during sexual reproduction of active damage clearance and the best example I mean the closest example to ourselves to to mammals like us are mice and in mice something quite similar was observed by Maryland several years ago where she studied exactly the same process of uh sexual reproduction and damage clearance in germline cells in you know fertilized eggs that happens as part of the sexual reproduction in in these organisms and basically she demonstrated that during early embryogenesis just after fertilization in the several days after use have active clearance of damage again carbonylated proteins Advanced glycation and products and Etc in Mouse egg cells which is very close to you know our embryogenesis as well mammalian embryogenesis so it's essentially I would say guarantee that we have the same process in human cells happening during human embryogenous active clearance of damage and she narrowed it down to this 20 subunit of the Proto so I'm showing that it's the protosomal mechanisms that are responsible for clearance of damage during mouse embryogenesis that clear that damage and she had very good methodology showing the accumulated damage in mirin all sides and after visualization showing where the damage gets localized and actual clearance of the damage and she showed that for example carbonylate proteins accumulate just outside of the nucleus and within the cytoplasm of of the fertilized egg and then she followed it through the process of embryogenesis and cell divisions that happens during marine embryogenesis and show that over time several days after fertilization levels of damage in for example here carbonylated proteins next slide ages get drops within days to much much lower levels essentially to to zero during the active process of damage clearance and also she visualized that this damage actually uh doesn't damage clearance doesn't happen immediately but it starts happening when there's active differentiation of embryonic stem cells in in a blastocyst and the the if the damage is actually localized in the Inner Cell Mass that's shown here I wish I had a pointer on this slide and basically she was able to track it down during the embryogenesis process and and showing that this damage gets cleared over time and she asked a very good question basically why is it that aged tissues accumulate this damage and actually she showed that in in the embryonic stem cells before the active process of damage clearance the level of this damage is is similar to to like the liver and the brain of old or not old sex six months old mice you know adult mice but yet they're fully cleared during the emergence process in in germline cells but why not in somatic tissues so this kind of question that I think we're all asking why do genes decide to reserve this process only for sexual reproduction but not for keeping us healthier for longer uh so I think you know we we don't really need to answer that question as long as we can actually use these Pros processes you use the mechanisms of damage clearance that are already present in the genes of our organism and maybe just activating those genes in the somatic cells and this actually ties back into partial reporgan where I think partially programming activates some of these mechanisms and some of these Pathways to actually actively clear the damage and so the conclusions of her numbering listed here basically uh show that there's active Rejuvenation happening after fertilization in germline cells and the key active mechanism that she narrowed down was protosomal degradation of carbonylated proteins and AGS in addition to of course there's many other things that happen during embryogenesis complete reset of the epigenetic landscape methylation landscape Etc but she didn't she didn't focus on that she focused on actual damage protein accumulated damage in murine cells and speaking of carbonyl proteins and protosomes there were examples in other species showing very similar mechanisms clearance of carbonylated proteins and there is kind of two schools of thought one thing so it's the protosome other things it's the lysosome that plays the key role and as I mentioned Moline hernabring thought it's the protosome or had data showing it's a protosome and other groups for example in drosophila showed also that the protosome plays a key role this is a very cool experiment that they did they showed a particular uh subunit 26 subunit of the protosome was critical for lifespan of drosophila if you down regulate this subunit flies live for much shorter time period if you upregulated this actually extends lifespan of drosophila and so the authors concluded that you know solar degradation of carbonylated proteins and other misfolded proteins is a key mechanism for Rejuvenation in inrosophil including germline Rejuvenation and they were able to kind of repurpose it for somatic Rejuvenation and extending lifespan in the Flies also another group showed in nematodes also that it seems to be the protosome playing a key role in clearing damage Journal energy during General Rejuvenation in nematodes whereas another group and I have a few slides after show that as it's actually lysosome so there's kind of again two schools of thought but I think it would be good to upregulate both lysosomal and proteosomal mechanic in somatic cells and you know enjoy the Machinery of Rejuvenation in our somatic cells and finally on nematodes there there was a very interesting paper that showed very nice visualization that the germline cells the egg cells in nematodes actually have higher levels of damage than surrounding kind of somatic tissues so again it's not that the germline cells are somehow privileged from accumulated damage on the contrary here you see that at least in the levels of kind of oxidized levels of oxidation and oxidized proteins they're higher than surrounding tissues and yet when it it's time for them to get fertilized they're actively cleared of that damage and you know this is the actual Machinery that helps them enjoy Rejuvenation rather than a process of prevention of accumulation of this damage and so this is the work in nematodes that I mentioned by Cynthia Canyon's group and Adam Bonner in in her group that showed that in nematodes they studied in in deep detail what exactly happens during nematodes and they showed that in nematodes it's actually just before fertilization that this active clearance of damage happens because nematodes they sell fertilize they actually know when the fertilization event is going to occur and so just before that they start clearing the damage of their egg cells and the major kind of pathway there is the signaling pathway uses the major sperm proteins that kind of induce this rejuvenating event and induce this Machinery to clear the damage in in their in their egg cells and so yeah basically the next two slides summarize these findings showing that nematodes can clear the damage in in their egg cells on demand when they know that they're going to be fertilized they activate this clearance machinery and so it's the major sperm proteins that play the key role and if they mimic just the signaling they also can prevent aggregation of uh this this damage in their all sides and as I mentioned when they when they Dove deep into the mechanisms of this damage clearance the group of atom Bonner and Cynthia Kenyan they show that it's the lysosome that plays The Cure rather than protosome and they they the way they kind of were able to conclude this they knocked down or knocked out several key mechanisms of lysosomal degradation and were able to show that one of the subunits the V8 of v80pas lysosomal proton pump is important for this damage clearance and if actually they disable or knock down the subunit that you get much worse damage clearance so they were they concluded that lysosomal degradation it plays a key role here in in nematodes and to kind of bolster their conclusions there's some data from frogs that also argues that it's actually the lysosome that plays a cure role but as I said between lysosomal upregulation of lysosomes and protosomes it could probably would be good to upregulate both to uh be able to clear the damage in somatic cells but here in in frog oocytes they were showing that it's the lysosome that can that there's active clearance of damage in frog cells and it's the lysosome that plays a key role there now to try to tie it back to reprogramming as I mentioned that's what led me to believe reprogramming is repurposing some of the mechanisms of this germline rejuvenation uh there is great data from the Vadim gladyshev group and I know he's here in the in in the audience somewhere showing that epigenetic age is also not immediately reduced during the embryogenesis process but actually reaches immuno a minimum just before gastrulation or at gastrulation uh so this I think uh dovetails well with the observations of Malin herrenberg that show that again damage is not cleared immediately after fertilization but it's a gradual process that reaches a minimum I think eight days in mice that were in malin's results and here in vadim's result in vadim's groups results they also find the minimum around like eight to ten days during miles embryogenesis and as as we all know reprogramming has been shown to ameliorate all cellular hormone Hallmarks of aging on in a single cell and including clearance of damage and misfolded proteins Etc and so to me uh kind of the natural question because reprogramming already recapitulates a lot of this embryogenesis biology because essentially we're introducing the factors that are responsible for maintaining stemness and embryonic stem cells when we introduce those factors into somatic cell that somatic cell essentially kind of recapitulates the or moves back on the epigenetic lens came all the way landscape all the way back to embryonic state so it's to me very possible that the mechanisms that enable this clearance of damage are also the same mechanisms that are activated during the embryogenesis process and embryonic stem cells as was shown by million bring in in mice and in addition to the physiological Rejuvenation that we see during reprogramming we know that even partial reprogramming but can restore more youthful levels of gene expression as two papers this one showed and this one showed that partially programming restores a more youthful pattern of gene expression a more useful transcript transcriptome but more importantly on the physiological level just partially programming just kind of the beginning stages of reprogramming induce this Rejuvenation in the cells that reprogramming targets and so to me this all kind of ties back again into what exactly are reprogramming factors or yamanaka factors and of course we know that these factors are responsible for supporting stemness maintaining stemness on in embryonic stem cells and uh and of course they're also a Pioneer transcription factors they're able to access condensed chromatin open it up and induce gene expression of previously suppressed genes and transcription factors triggering kind of a Cascade of uh you know other transcription factors but also another aspect of human Aqua factors is that October OCT 4 and sox2 are also the factors that trigger this maternal to zygotic transition during early embryogenesis in mammals and this kind of falls in the same time period as this observation of epigenetic age reaching a minimum during gastrulation which kind of tying it all back together to me seems to imply that there could be some sub-programs that induce active damage clearance induce Rejuvenation and not just transcriptomic epigenetic but actual physiological Rejuvenation and clearing carbonylated proteins Etc that get activated during the early stages of reprogramming even partial reprogramming and this could be responsible for the observations that we see the partial reprogramming and we have these These are empirical observations that partial reprogramming just partial reprogramming can produce rejuvenating effects on on cells and so uh yeah I think this is a great quote regarding guest relation that it's the most important period in our life I think the observation that our epigenetic rage reaches minimal gastrulation and that we're rejuvenated during gastrulation plays back uh well to this quote so uh to conclude uh I think hopefully you know in this kind of quick Whirlwind tour of Decades of research into germline Rejuvenation I was able to at least kind of interest you in diving deeper into this topic and trying to figure out what exactly are the mechanisms that nature already has that maybe we can recapitulate and of course to me personally I think partial reprogramming is one such mechanisms it's far from ideal but or at least where you have it and that's why I think we should try to translate it as quickly as possible where some people should try to translate it as quickly as possible but other people fundamental resources should dig deeper into the mechanisms of that induced Rejuvenation germline cells and figure out how we can kind of apply them in the context of an already foreign organism and be able to kind of get control back from from our genes and control of our biology so with that thank you very much if you have any questions I would love to answer them [Applause] thank you so much maybe we have time yes for one or two questions before we go to our short break is there a mic around yeah it's coming here we have a question maybe you can raise your hand so it's easier for them to find you thanks so much thank you always fascinating um at the moment what is as far as you know the difference between Rejuvenation with the yamalaka factors in the best case situation and Rejuvenation by Nature you know uh yeah from the Native the cells who are going to give another animal yes thanks DJ I think it's a it's a great question because yeah obviously with the yemenak factors I mean we can fully rejuvenate a cell in a Petri dish and you know create a colony of fully rejuvenated cells with that if we redifferentiated back into original tissues have fully restored the functions a mitochondrial function that's a great example of uh fibroblasts from 100 year old donors that have suppressed mitochondrial function but if you reprogram them into prepotent stem cells and then back into fibroblasts they're like young like young fibroblasts with fully restored mitochondrial function so on a cellular level reprogramming can do this the problem is you can't do full reprogramming on you know in Vivo in the context of adult organisms because you can't afford to lose cell identity so definitely partial reprogramming is not there yet but on on you know full reprogramming I think it's already recapitulating a lot of urination that you know Nature has reserved for for journaling cells hopefully that that kind of answers the question uh well in terms of Hallmarks of Aging I don't think so because as it can slide summarized on cellular Hallmarks of Aging full reprogramming ameliorates all the cellulose homework solution of course there's you know extracellular Hallmarks of Aging there's a matrix and all of the other problems with signaling for example that is not even you know captured by by single cell reprogramming and so and of course the during reproduction it doesn't really care about the extracellular matrix it's something that could be another aspect why I chose to do that I can just build a whole new Matrix from scratch so there's still definitely ways to to for us to explore other ways of Rejuvenation in the in other contexts and clearance of damage in in other contexts any other questions I guess not thank you so much Yuri once again um great talk [Applause] | ↗ |