WHAT Is the MTOR Longevity Pathway?

WHAT Is the MTOR Longevity Pathway? by Edward Van Harmelen 8 min read The mechanistic target of rapamycin (mTOR) is a longevity pathway that plays a vital role in aging, growth, metabolism, and disease. Find out why it’s important to know about mTOR and how to keep it in balance. What is mTOR? mTOR is a protein kinase (an enzyme that modifies other proteins) that regulates cell growth and metabolism. It’s a complex pathway that’s critical to many cellular processes. But, in short, it's a survival mechanism that signals to the body and cells that they should grow during times of plenty and not grow when food is scarce. It’s a bit like the central processing unit of a computer that makes all the complex decisions relating to cellular growth and it’s one of the longevity pathways. For more on the longevity pathways, read: The Longevity Pathways - How to Live a Happy, Healthy and Long Life As with all longevity pathways, this one should be kept in balance so that the body functions optimally. Although the exact mechanisms are still a mystery, too much mTOR has been linked to a shortened lifespan, cancers, and many chronic health conditions, and too little mTOR could cause other health issues such as liver problems, muscle atrophy, delayed healing, and disrupted insulin sensitivity. Here’s a brief explanation of mTOR from Dr. David Sabatini: Is mTOR Good or Bad? Because of the many critical processes that it regulates, mTOR shouldn’t be viewed as good or bad but rather that it has a function, timing, and purpose. Here are some of the ways that mTOR benefits the body when it’s functioning optimally: It promotes muscle growth When mTOR is activated, it stimulates muscles to grow through the activation of various hormones. Loss of muscle mass is one of the first signs of aging which is why activating this pathway through exercise is so beneficial for your health and longevity. mTOR increases metabolism As mentioned, mTOR signals to your body that it’s time to grow and repair. Some of the ways it does so is to regulate the production of ATP, create new mitochondria, and increase metabolism. Studies have shown that mTOR is essential for proper metabolic regulation, which is consistent with its role in coordinating anabolic and catabolic metabolism. It slows aging Methods to slow aging have often been the pinnacle of medical research. The last decade of research shows the answer might lie within the nutrient pathway controlled by mTOR. mTOR, in response to calorie restriction, has been shown to extend lifespan and slow the onset of age-related diseases. mTOR seems to inhibit fear memory reconsolidation In a study of male subjects, inhibiting mTOR was shown to block the reconciliation of lasting fear memory. This study suggested that inhibiting mTOR might be a way to help people suffering from acquired anxiety disorders such as Post Traumatic Stress Disorder (PTSD). However, the over-activation of mTOR has also been associated with many diseases. Scientists are still unclear on the details as to why they find higher levels of mTOR or why inhibiting it produces beneficial results. Here are some of the conditions that are associated with mTOR: Some types of cancer mTOR is linked to cancer because it increases the process of angiogenesis (the formation of new blood vessels from pre-existing ones) which helps the growth of tumors. Scientists are hard at work researching inhibiting mTOR as a potential cancer treatment. Autoimmune diseases mTOR activation is recognized as a biomarker and one of the main pathways to autoimmune disorders, obesity, and other conditions. In autoimmune disease, the activation of mTOR is thought to be due to oxidative stress. Currently, much research is being conducted on ways to inhibit mTOR as a means of treating autoimmune conditions, obesity, and certain cancers. Depression The activation of mTOR has been shown to be involved in many physiological processes in the nervous system and higher nervous system functions such as cognition, survival, appetite, and eating behavior, as well as the control of the sleep-wake cycle. Because of the central role that it plays, researchers have hypothesized that changes in mTOR signaling may underlie pathologies such as depression. Research has shown that blocking the signaling pathways that stimulate mTOR shows the potential for the development of antidepressants. Diabetes Diabetes is a condition that’s associated with high blood sugar levels and a resistance to insulin. Here’s a brief video by the Animated Diabetes Patient on Understanding Type 2 Diabetes. Studies have shown that inhibiting mTOR increases the process of glycolysis (breaking down sugar) thereby increasing insulin sensitivity in muscle cells. Alzheimer’s and cognitive function According to researchers, increased levels of mTOR are associated with Alzheimer’s disease. A recent study found that the inhibition of mTOR enhanced learning and memory in younger subjects, whilst maintaining memory in older ones. It’s thought that inhibiting this pathway shows therapeutic potential for this devastating condition. Autism Growing evidence suggests that a wide variety of autism disorders may be linked to dysregulated mTOR activity. The collected data suggest that disinhibited mTOR may contribute to or cause autism spectrum disorder. It is important to note that although many of these diseases are commonly associated with the overactivation of mTOR, many genetic and environmental factors influence this risk. Overactivation of mTOR in no way guarantees that every mTOR user will experience or develop these diseases. What Stimulates mTOR? mTOR activation is mainly linked to a variety of amino acids, the hormone insulin as well as testosterone. It’s important to remember that activating mTOR through exercise is healthy and it has an important role to play in preventing loss of muscle mass, repairing tissue, and many other cellular processes. The following are all linked to mTOR over-activation: Excessive amounts of leucine-rich proteins -regularly eating too much red meat, chicken, tuna, beans, cheese, milk, and eggs will activate mTOR. The recommended daily amount of protein varies from 46-63 grams for most adults. Excessive calorie intake -regularly consuming more than your body needs will lead to weight gain and will also over-activate the mTOR pathway. According to the NHS, men should eat about 2 500 calories (10 500 KJ) per day and women should eat about 2,000 calories (8 400 KJ). Most people consume way more calories than they need during the day which is why obesity rates are at an all-time high globally. Excessive carbohydrate intake- carbohydrates fuel our bodies but most of us eat way more carbohydrates than we need. Excessive consumption of carbohydrates leads to weight gain, obesity, cancer, and many other health conditions. Unfortunately most commercially prepared foods and sweet foods contain hidden sugars and unhealthy carbohydrates that send levels soaring way over what they should be. The Dietary Guidelines for Americans recommends about 225 to 325 grams of carbohydrates a day. Did you know that people who live in the Blue Zones all practice some form of calorie restriction? To find out more, read: Lessons from the Blue Zones - Feel Younger for Longer How to activate mTOR in a healthy way mTOR is activated through exercise. Exercise seems to increase mTOR in the muscle, brain, and heart but inhibits mTOR in the fat and liver cells. When activated in the brain, it improves memory and learning and the inhibition in the liver cells and fat cells may be one of the reasons why exercise is so good for these organs. Interestingly, omega 3 fatty acids also activate the mTOR pathway and encourage the beneficial properties of muscle growth and healing. The exact mechanism is still unknown but researchers think that it may have something to do with its anti-inflammatory properties. Did you know that Krill Oil is a highly-effective source of omega 3 fatty acids? Find out more in What is Krill Oil and Why Is It Good for You? What Inhibits mTOR? If you are functioning at optimal health, then mTOR should be inhibited naturally by the balances and checks that your body should have in place. However, with aging, optimal cell function tends to decrease so here are ways to inhibit mTOR. Calorie restriction and activating AMPK Calorie restriction means reducing daily caloric intake without causing malnutrition. It has been linked to extended lifespan and increased health benefits in numerous studies. Restricting calories inhibits mTOR and also activates AMPK - another longevity pathway that is known as the metabolic master switch. Although fairly easy to do in the short term, it’s very challenging to restrict calories for most of your life. The good news is that you can also take natural supplements that mimic calorie restriction such as berberine to experience the benefits of calorie restriction such as inhibiting mTOR. Our product RELEAF contains Berberine, PQQ, and Silymarin and is specifically designed to increase AMPK and inhibit mTOR. Silymarin or milk thistle has been shown to significantly inhibit cell proliferation by suppressing the mTOR pathway. For more on calorie restriction, read: Five Easy Anti-Aging Hacks to Increase Your Longevity. Exercise Exercise both activates and inhibits mTOR in all the right places. It inhibits mTOR in the fat and liver cells but activates in the brain, muscles, and heart. Daily exercise is possibly one of the best ways to balance mTOR and AMPK and is key to extending your life and healthspan. Resveratrol, curcumin, and quercetin Resveratrol is a polyphenol that is a powerful antioxidant that has anti-inflammatory and neuroprotective properties. It’s found in grapes (mostly the skin and seeds), berries, and red wine. Studies have shown resveratrol inhibits mTOR. Curcumin, found in turmeric, may have anticancer properties through the blocking of mTOR pathways in tumor cells. When taken with piperine (black pepper) it significantly helps the body decrease inflammation and oxidative stress (one of the triggers that may cause increased mTOR). Quercetin (a natural pigment found in fruits, vegetables, and grains) has antiviral, anti-inflammatory, and anti-carcinogenic properties. It’s a proven tool in cancer treatment and various other diseases through its ability to inhibit mTOR activity in multiple pathways. For more on the above polyphenols, read: Why Polyphenols Are Good for You Our product PRESERVAGEis rich in trans-resveratrol, curcumin, quercetin, and Bioperine which helps activate sirtuins and inhibit mTOR. How can you regulate mTOR? Research has shown us that to use mTOR in a way that best benefits our bodies, we need to activate mTOR during periods of exercise to maximize muscle growth and keep our mTOR levels low at other times to promote health and longevity. The following can be achieved by: Stimulating mTOR through exercise and consuming protein straight after you exercise to maximize muscle growth. Remember, exercise stimulates mTOR in the brain and muscles but inhibits it in the liver and fat cells. Decreasing protein and carbohydrate intake but keep in mind that these levels will be greatly determined by how much exercise you perform, especially resistance-based exercising. Increasing good fats while decreasing proteins and carbohydrates, especially on days when you are not exercising. Taking a caloric restriction mimetic such as berberine. Conclusion Our bodies are incredibly designed and with good care, we can live long and happy lives. By implementing a well-balanced healthy diet that’s not high in calories, protein, and carbs, as well as exercising regularly, you use the longevity pathways to your benefit. Don’t forget, taking our natural supplements will also help you on your path to feel younger for longer and give you a leg up to achieve your goals. The content of this article is for informational purposes only. It’s not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or health provider before starting a new health regime or program. Do not ignore medical advice or delay seeking it because of something you’ve read on this site or any Youth & Earth product. mTOR signaling in growth and metabolism 6,009 views Jun 30, 2022 Sjöberg Prize Laureate 2020 Michael N. Hall, Universität Basel, Switzerland. From: Sjöberg Prize Lectures, 2022-06-13. Transcript Follow along using the transcript. Show transcript Vetenskapsakademien 4.28K subscribers Videos About 5 Comments rongmaw lin Add a comment... @hs2336 @hs2336 10 months ago Thank you for sharing, very helpful! 3 Reply @peouspaul1258 @peouspaul1258 1 year ago (edited) If we modify mtor to check scfa status instead of protein before replication of cells then most human disease will disappear.. 2 Reply 1 reply @bruceroseman5616 @bruceroseman5616 10 months ago Ausgezeichnet 1 Reply @dr.tranngocthien @dr.tranngocthien 2 months ago thank you very much Reply Transcript Search in video 0:07 so first of all thank you very much for these very kind words of introduction 0:13 i'd also like to begin by saying that i'm immensely honored and delighted to 0:19 be a recipient of the showbag prize to have our work recognized in this in 0:25 this manner so i also feel uh very strong emotions of 0:31 of gratitude for this uh which i will get to later before i i 0:37 do that i would like to uh tell you a little bit of our about our research 0:42 in the laboratory and what i'd like to do well first of all we work on 0:48 cell growth control particularly the tor signaling pathway is as bank mentioned 0:53 and what i'd like to do today is not give you an overview of the work in our laboratory 0:59 but rather to focus on one story one current story it's an unpublished story 1:04 which we're very excited about and it deals it's one of the cancer 1:10 related projects in the lab as bank said torah is involved in many different 1:16 disease areas and we work on many different disease areas but this one story uh deals with with cancer 1:25 um but before i do that i'd like to give you a brief introduction to tor signaling 1:32 so what you have here is a condensed overview of the tor field 1:38 this on the left is the very first ever model of tor signaling published one we published 1:45 shortly after our discovery of tor in 1991 i have to say 1:51 i'm actually embarrassed we published this model it uh it says very little other than the 1:56 fact that tor exists there are more question marks here than anything else it actually reminds me of a gary larson 2:02 cartoon more than a serious uh uh publica a serious model you'd find in scientific publication i don't know how 2:08 many of the people how many people in the audience remember gary larson but i'm sure the older members of the 2:14 audience do since this very early rudimentary model 2:20 the field has progressed this is a more up-to-date model but it's also now hopelessly out of date 2:27 we've stopped drawing models of complete models of torch signaling it's become so complex you'd have to do this in three dimensions 2:34 and what's driven this complexity uh uh in the tor signaling network is this 2:41 exponential increase in publications in this area and what's driven this uh increase in 2:47 publications that tor turned out to be both fundamentally important and clinically important much more so than 2:54 we suspected when we first started working on rapamycin back in the late 1980s 3:00 so um let me uh take you back a little bit uh 3:06 as a way of introducing you to the tor signaling pathway so this is rapamycin so the protein we 3:14 work on tor as you heard stands for target of rapamycin and this is the rapamycin is a drug it's 3:22 a natural uh drug it's a natural secondary metabolite secreted by 3:28 a soil bacterium which was isolated on on easter island also known as rappanui 3:34 hence this drug is called rapamycin and 3:41 this the bacteria which produces were originally isolated by a group of scientists in the 1960s and what they 3:49 were looking for were bacteria which produced some novel metabolite which they could then develop 3:55 into an anti-fungal they did find the isolate this and found it did have 4:00 anti-fungal activity but as they were developing as an anti-fungal they realized it had the undesirable side 4:06 effect of suppressing the immune system and of course suppressing the immune system is the last thing you want to do 4:12 to somebody with a fungal infection so it was immediately rejected and discarded 4:17 until uh years later it was now rediscovered for the very property for which it 4:23 originally been discarded for immune suppression so the 1980s and 90s uh 4:29 transplantation surgery came into the clinic as a viable procedure due the development of immunosuppressive 4:36 due to development of immunosuppression and it was drugs such as rap mice and others like cyclosporin a which allowed 4:43 this development in the clinic of transplantation surgery so now 4:48 if you have liver transplant the chances of survival are large 4:54 if you had a liver transplant in let's say 1980 chances of survival were were small 5:02 however since uh the original development of rapamycin as an immunosuppressive it's now become even 5:07 more famous as an anti-cancer drug and it's also now used in the clinic 5:13 to treat cardiovascular disease rest no restinosis after angioplasty in particular 5:19 so it has applications in three major very different therapeutic areas which also already begins to hint to the 5:26 fact that whatever this drug must do whatever this drug does it must 5:33 do something rather central to affect such different diseases so what does tor 5:38 actually do the target of of rapamycin the protein which this drug binds and 5:44 inhibits well the tor protein is a kinase it's a protein kinase very highly conserved 5:51 protein kinase can serve all the way from yeast to mammalian so this is an assumption we made early on when we 5:57 started working on yeast to attempt to elucidate the mechanism of action of the drug 6:04 and what this uh kinase does it 6:09 it forms a central hub in controlling cell growth and by cell growth i mean 6:14 increase in cell size or cell mass not increase in cell number and it does that by controlling a large 6:20 number of cellular processes which collectively determine mass accumulation and thereby cell size 6:26 and these proper and these processes can be subdivided into two groups the anabolic processes which tor activates 6:34 and the catabolic processes which tor inhibits so what tor does it balances these opposing forces of synthesis and 6:40 degradation such that the cell will accumulate the appropriate level of mass 6:46 in response to whatever nutrients might be available so in very simple terms what tor does 6:53 it controls our growth in response to to when we eat 6:59 so how does tor actually control all these different cellular processes well there are effector signaling 7:05 pathways which emanate from tor which then intersect with key proteins involved in all these processes and in 7:11 some cases we know what those effector pathways are and some we don't but uh over the last uh 30 years uh and 7:18 something i failed to mention in the previous slide is that we discovered tour 30 years ago so we just celebrated 7:23 the 30th anniversary of the discovery tour so over these 30 years we uh 7:28 we've uh uh described what we call the tor signaling network and i 7:35 refer to it as a network not as a signaling pathway but it's in fact more than a single pathway it's actually two 7:41 pathways and this network is defined by these two complexes which 7:47 we discovered in about the year 2000 2002 which defined these two pathways 7:54 each one of these uh complexes the central catalytic subunit of which 7:59 is tor in this case mtor from mammalian tor each one of these 8:04 complexes is functionally and structurally distinct so each phosphorylates its own substrates to 8:09 control its own processes and this is a major uh advance because it told us that taur is in fact two separate kinase it's 8:18 not a single kinase now like a tor itself which is concerned 8:23 all the way from yeast to mammals these two complexes are also conserved all the way from yeast to mammals in 8:31 fact the entire architecture of the network is conserved all the way from yeast 8:36 to mammals so the picture that's emerged is that this is a primordial or ancestral signaling network which is 8:42 controlled which has been conserved throughout eukaryotic evolution to control this very fundamental process 8:48 of cell growth now the exception to that statement i just made is this part of the network up here 8:55 which is the growth factor signaling uh pathway which evolved later this evolved with multicellularity and when that was 9:02 then grafted onto this more primordial tor signaling of components which are 9:07 already already existed in unicellular yeast and the reason for that is that growth 9:12 control in multicellular organisms or metazoans is more complex than growth control and unicellular organisms 9:19 because in multicell organisms it's critical to control the growth of every cell in the body 9:25 relative to every other cell in the body such that our organs end up being properly proportioned and that then is 9:31 what this part of the network achieves this controls growth into a in response to growth factors which control growth 9:37 over a whole body plan so now we know in uh mammalian cells tor is activated by three inputs the growth 9:44 factor which then controls growth over the whole body over the whole body plan uh combined 9:50 with local nutrients amino acids in particular and then energy local energy 9:56 atp in particular so when these three factors are present energy nutrients and growth factors the entire torso network 10:03 is activated these anabolic processes are are turned on catabolic processes are turned off and cells will grow 10:10 now another fascinating aspect of the tor signaling network is the large number of disease to which it's been 10:16 functionally linked and these diseases all have in common 10:22 that they are due to inappropriate or ectopic cell growth and these can be malignant forms of cell 10:28 growth such as cancer or benign forms of cell growth such as cardiac hypertrophy 10:33 but in all cases cell growth it's been calculated the torah is upregulated 10:39 and contributes to cancer in about 70 to 80 of all tumors 10:44 now uh more recently torr has been implicated another set of disorders the so-called metabolic disorders we know 10:51 chronically high levels of circulating nutrients can upregulate the tor pathway even in the absence of growth 10:58 factors and this can lead to adipogenesis and obesity which can in turn lead to type 2 diabetes 11:04 but more common a more direct route to type 2 diabetes 11:10 is through this negative feedback loop in the tor signaling network in which high levels of tor 11:15 can inhibit irs in the insulin signaling pathway and thereby confer insulin insensitivity 11:23 which as you know is one of the hallmarks of type 2 diabetes and this then 11:28 in this in this context some have actually argued that rapamycin uh via 11:33 inhibition of tor could lead to inhibition of this negative feedback loop and restoration of signaling 11:39 through the insulin pathway and therefore could be applied now in a fourth therapeutic area diabetes 11:45 i don't think any pharma company is actually developing rap mice as an anti-diabetic because 11:50 there are a number of of complications which would prevent that but something it gives at least credence 11:55 to this notion is the fact that metformin the world's most commonly prescribed anti-diabetic works at least 12:01 in part via inhibiting mtor via ampk 12:07 and the talk i will give in just a moment about our current research deals with the role of tor in 12:14 cancer i will not talk about diabetes today now over the last 30 years while we've been trying to 12:20 define or understand tor the physiology and pathophysiology of tor we've also been trying to understand 12:26 the tor function at the atomic level and a few years ago we published the structure of mammalian tor complex one 12:34 which is shown here it is a dimer of heterotrimers 12:39 so it contains so the blue and gray is the mtor protein itself 12:44 the green is another protein called raptor and the orange is another protein called 12:49 list eight because it's a dimer it has two catalytic uh sites a catalytic cleft here this is a 12:57 rather conventional structure of a kinase a bilobe structure with a catalytic site between the two lobes 13:03 we also determine the structure of rapamycin bound to torque complex one to 13:08 understand how this drug inhibits a tor complex one and what i've not told you 13:14 is that rapamycin acts first by binding a small protein in the cell called fkbp 13:19 and it's then this fkbp rapamycin complex which binds to tor and we never knew why we needed 13:27 both rapamycin and fkbp to inhibit tor because rapamycin alone 13:33 can bind tor but not inhibited and the structure elucidated or provide an answer to this 13:40 question so if you'll keep your eye focused here and here so this is fkbp 13:47 and rapamycin would form a glue much like the glues you'll hear about later which binds then fkbp to the lip of the 13:54 catalytic cleft and this then reveal the mechanism of action of this drug because it 14:00 the way the drug works is by binding or gluing fkbp to the lip of this cleft it 14:07 forms a lid which blocks acid access of substrates to the catalytic site which is at the bottom of this uh left here 14:13 very unusual mechanism of action for a kinase inhibitor 14:19 more recently more recently we've also determined the structure of tor complex 2 mammalian human tour complex 2. 14:26 that's shown over here what we learned is tor itself here in blue has the same structure in both complexes it's now 14:32 decorated by different substrates to to confer the different function of torque complex too compared to tor complex one 14:42 and i think we learned much from the structure of this as well but i think the most interesting thing we learned is 14:47 it resolved a question since we've been dealing with since 2004 and that is we 14:52 knew fkbp rap myosin could bind and inhibit tor complex one but we also knew 14:58 that it could not bind inhibit tor complex ii so why is tor in tor complex one sensitive but tor and tar complex 15:04 two insensitive rapamycin and the structure revealed the answer and that is that this subunit of torque complex 2 15:12 which is specific to tor complex 2 binds torn away which is masked the fkbp 15:17 rapamycin binding site so that fkbp shown here in red cannot bind the lip here and prevent access of substrates to 15:25 the catalytic site in tor in tor complex too okay so i've given you a kind of a rapid 15:31 introduction to torah both the physiology pathophysiology and structural aspects and i'd like to tell 15:36 you about this current unpublished work in the lab and this deals with arginine the amino acid arginine and how 15:44 it promotes liver cancer hepatocellular carcinoma and does so by reprogramming 15:50 metabolism so it's been known for many years that uh tor mtor uh promotes cancer uh too 15:59 much shore activity promotes cancer but the underlying mechanism was unknown so uh we decided to study this uh and to 16:07 do so we developed a a mouse an mtor driven mouse model of liver cancer to to 16:13 to study and we did that by again back to the mtor signaling network we deleted two tumor 16:20 suppressors in this network tsc and p10 and we deleted tsc 16:26 and we did this specifically in the liver we hyperactivate tor complex one 16:32 and then we combine that with a deletion of p10 we further activate tor complex one but 16:38 now we also hyperactivate torque complex two so both complexes are now hyper activated uh in this 16:44 mouse and we call this mouse the liver specific double knockout this i'll be 16:50 referring to it in some slides ahead so what did we see uh in this mouse um 16:55 well uh deletion of these two tumor suppressors occurs at birth and we see that 17:01 at four weeks of age we see hepatomegaly or enlarged liver and this continues throughout the lifetime of this mouse 17:08 and this is due to this growth inducing aspect of hyperactive tor signaling the parasites in these livers 17:15 are bigger and the liver itself gets bigger by about eight weeks of age we start 17:21 seeing uh non-fatty liver disease or apatostatosis which then progresses to an inflamed 17:28 liver and by about 16 weeks of age we start seeing very mild 17:34 forms of hepatocellular carcinoma or liver cancer and then by 20 weeks of age there's very 17:41 severe liver cancer in these mice and the mice have to be sacrificed at this at this at this point 17:48 so uh we want to understand what is giving rise to these uh tumors in this liver 17:55 in a tor dependent manner so we applied many different omics approaches to 18:01 to these tumors and what i'd like to start with is the metabolomic study we did 18:07 so we excited these individual tumors we did study the metabolites in these tumors by 18:13 mass spec we identified about sixteen thousand metabolites of which four 18:19 thousand were annotated and of these four thousand about a thousand changed in the tumor versus control non-tumor 18:26 tissue from this liver and we did the pathway enrichment analysis we found that the metabolic 18:32 pathway most affected was amino acid metabolism we then did target analysis of of all 18:38 the amino acids in the tumors and we found indeed some amino acids change 18:44 most of those who change most are decreased but one amino acid in 18:49 particular and the one where the change was perhaps most dramatic there's an increase and this is specifically for arginine 18:57 so we of course wondered why is arginine increased and how is this at all related to 19:03 the ability of the tumor to grow so we the first thing we did then was to 19:09 look at our transcriptomic and proteomic studies to see if the 19:14 arginine biosynthetic pathway was affected so this is the arginine biosynthetic 19:20 pathway and let me introduce you to this key here the box on the left 19:25 refers to mrna so this data from the transcriptome the box on the right is data from the 19:31 proteome it's a protein and blue means it's down red means it's up and as you can see all the enzymes 19:39 the genes encoding and the proteins of the arginine biosynthetic pathway which is by the way is part of the urea cycle 19:47 all these uh are down despite the fact that arginine levels are up this was a 19:52 little counter-intuitive so we assumed that 19:58 the there are high arginine concentrations in these tumor cells due to increased import of arginine from the tumor 20:05 environment and there are two types of hisidine transporters uh 20:12 so-called uniporters and then anti-porters anti-porters are different from uni-porters and these 20:18 rely on an it has to be exported to bring arginine into the cell and glutamine is normally 20:24 the anti solute that's used and there are several 20:30 different versions of these two different transporters as listed here so we went back to our data and looked to 20:35 see whether these transporters are changing expression indeed they are all 20:40 uh almost all are up regulated in the tumor compared to non-tumor tissue 20:46 we couldn't detect the protein uh by uh mass spec because they're membrane proteins they're difficult to 20:52 detect but we can confirm by immunoblotting if these proteins are indeed increased in the tumor compared 20:58 to controls in addition uh uh recently the christophel has shown 21:03 that in the case of liver cancer it's not glutamine which is anti-solute for the anti-transporter 21:09 but it is asparagine and indeed we also seen the 21:15 asparagine synthetase is upregulated in the tumor uh compared to non-tumor so everything 21:20 you need now to increase import of histidine is upregulated in these uh in these tumors 21:27 we actually did arginine transport assays ex-vivo material from the tumor we found indeed 21:34 arginine uptake is increased in the tumor compared to the control so this then explains why arginine levels are so 21:41 high despite the fact that that the arginine biosynthetic pathway is is 21:48 down i should say that it's long been known that arginine pathway 21:53 is down in tumors of many different types but it was always assumed that arginine levels would also be down because no one 21:59 would ever check arginine actually checked arginine levels so we wondered whether these high arginine levels are important for tumor 22:05 genicity so we went back to our mouse model and put them on different diets one with 22:12 full arginine ten percent of normal arginine levels and one percent of arginine 22:18 at eight weeks and then looked at the livers at 20 weeks of age and what we found is as we decreased 22:24 arginine in the diet we indeed reduced the tumor burden in these livers and 22:30 that's quantified over here tumor levels 22:36 indeed decreased dramatically and we looked uh as said arginine levels 22:42 in the cells of these hepatocytes and non-tumor cells of the 22:48 of these mice and we found that indeed arginine levels were down in non-tumor 22:53 tissue and in the few escaper so-called escaper tumors which arose in these tumors 23:00 arginine levels were high again a very strict correlation between high arginine levels and tumor genicity suggesting 23:07 that the arginine is indeed important for for tumor genicity 23:14 so now the question is what is the arginine being used for 23:19 arginine is a exceptionally versatile amino acid because it's used not only 23:24 for protein synthesis but it's also used to produce other amino acids it's used 23:30 as a signaling molecule it's actually one of the key amino acids involved the activation of tor complex one 23:38 and it's also a precursor for poly amines creatine and nitric oxide and we just we eliminated all of these 23:46 and we were left with poly means we wondered could the cell accumulate high levels of arginine to produce poly means which are 23:53 an essential metabolite in in cells nobody really knows what polymines do but they're essential 24:00 so uh here's then again the pathway of of 24:05 arginine synthesis the urea cycle the transporters which bring in arginine and 24:11 this is then how arginine is converted to the polymers the parliamenes come in three different 24:16 uh forms putrescine spermidine and spermine and it's 24:22 and these are produced from arginine via two parallel pathways this is one here through 24:29 the enzyme agmatinase and the other one is through arge 1 which again 24:35 leads to production future scene which then be converted to the other amino acids so here in very simple form is what i 24:42 just showed you before arginine is converted to polymers through the action the redundant action of these two 24:47 enzymes and polymes are extremely abundant in in liver cells uh they accumulate up to 24:55 millimolar concentrations so it would make sense that the cell would go a great length to to be able to 25:02 produce polyamines however 25:08 we found much to our surprise that the enzymes which convert arginine to polymers are also off 25:17 and this was uh despite the fact that polyamine levels were extremely high in these tumors just 25:23 like what we'd seen for arginine the biosynthetic pathways down but the level of the product is is high 25:29 and so what this told us is that the 25:35 and we then show that poly means also the high level of palming is due to increased in import of polymers 25:41 and this was important because it told us that the arginine pool and the polymer pools are uncoupled from each other 25:47 so in other words the arginine is not accumulating high levels to produce high levels of parliament arginine comes in 25:53 through transport and parliaments do as well 25:59 so we wondered whether the arginine and agmet 26:05 genes are down or polyamine synthesis down to preserve high arginine levels 26:10 so we went back to our mouse model again and what we did here now we introduced 26:17 these two genes arg1 or agmat into our mouse in a way which they could 26:23 not be turned off as the tumor developed they put them under a different promoter and asked 26:30 what uh what are the consequences of this the idea being that now if we 26:36 ensure expression of these two enzymes uh we would then consume the the arginine and would this then bring uh 26:44 tumor levels down indeed uh the the tumor burden was decreased 26:49 dramatically decreased upon expression of either one of these two so it appears that uh 26:56 expression of arg one and agmat is is turned off to ensure high levels of 27:03 of arginine which tells us that it's arginine itself which is important for the tumors unmet unmetabolized arginine 27:13 so um then the question is what is this arginine being used for if we go to the 27:20 literature we find there there's emerging evidence that arginine is somehow involved in metabolic 27:26 reprogramming and perhaps the best most famous examples in t cells where 27:31 arginine activates oxidative phosphorylation and nucleotide synthesis so he wondered if 27:38 the arginine could be required for metabolic reprogramming in tumors such 27:43 that that new metabolism would support the proliferation of the tumor cells 27:49 and to study this we didn't want to develop a different uh a different system 27:55 we wanted to use cells because it's easier to do experiments with cells so we reviewed a panel of human cancer 28:01 liver cancer cell lines to see if we could find a cell line which mimicked what we'd seen 28:06 in in the mouse and we did in fact find one snu-449 found several we chose one 28:13 snu-449 which is lacking these two enzymes we could re-express arge and agmat in 28:21 this cell line this would then bring down arginine levels in these 28:26 in these cell lines and we could also find this cell line 28:32 upon re-expression of arjun agamat 28:38 cannot survive under low concentrations of arginine so this cell line mimics what we saw in in 28:43 the tumors in the mouse and now we can do experiments for this with this cell line 28:49 and we did determine the transcriptome of this cell 28:55 line with and without argen agmat so with and without arginine in other words and we 29:01 found indeed metabolism was significantly rewired uh 29:07 many different forms of metabolism aldehyde nad amino acid pyruvate glycolysis 29:14 simply upon changes in arginine levels 29:19 and we also then asked whether this is also relevant in human cancer and we looked 29:25 at human tumor biopsies tumor and non-tumor tissue from human 29:31 patients and again we found what we found in mice arge one is law and agmat are lost in 29:38 the tumor compared to non-tumor tissue arginine levels are also high in tumors 29:43 from patients and low levels of larger agmat also 29:49 correlated with low survival in these patients so are we seeing the mice we think is also relevant to humans 29:56 so this is a model summarizing what we think is happening this is a normal liver cell where we 30:03 have high levels of enzymes of the urea cycle producing arginine which are then 30:10 converted some of which is converted to polyamines but in the tumor this is all shut off uh 30:16 arge1 agmena are also turned off and this is to compensate for this the cells take up large amounts of arginine or 30:23 polymer from the environment and then we think it's this high arginine is acting as a novel kind of 30:30 second messenger in the cell to somehow reprogram metabolism at the transcriptional level 30:36 so we hypothesize there must be some arginine binding protein 30:42 perhaps a transcription factor which when bound to arginine can 30:47 activate or inhibit the genes leading to the metabolic pre-programming we see and this would 30:53 include the gene for asparagine synthetase which forms as a kind of a positive feedback loop because if we 30:59 have more asparagine synthetase we have more asparagine more uptake of arginine 31:04 more metabolic reprogramming so asparagine synthase is key so what we did to see if such a protein exists we 31:12 prepared extracts from tumors and snu-449 cells ran them over a 31:18 column containing a matrix coupled to arginine and see what kind of proteins arginine binding proteins we would pull 31:25 out we had we identified 42 different proteins we 31:30 knocked down all 42 of our top hits and see if knocking 31:35 anyone down would have the same effect of decreasing arginine levels in other words bringing down asparagine 31:41 synthetase and indeed one did rbm 39 which 31:47 is a splicing factor and also a transcriptional co-activator so now we can 31:53 update our model we think the high levels of arginine are binding rbm39 32:00 and this is then leading to metabolic reprobing reprogramming at the mrna 32:06 level we have confirmed that rbm 39 in vitro binds arginine and we've confirmed that 32:12 when we knocked down rbm 39 we we knock out this metabolic reprogramming so 32:17 we're quite excited about this um about this about this project and where we can go 32:23 with rbm 39 and of course it could be a a good target for for therapy 32:29 okay uh i'm sorry i've run overtime i see i get let me uh quickly give credit to the people in the lab who have 32:36 done this work this is mainly the work of a very good postdoc by the name of dirk ma dirk mossman who was also helped 32:41 by others the earlier structural work i presented was also recent work this is 32:47 done in collaboration with my colleague tim meyer at the build centrum and then advanta dth both structural biologists 32:55 okay i would also like to uh at this point uh express my my deepest gratitude uh to the schoberg 33:03 uh uh foundation uh for for recognizing encouraging our work 33:10 this is extremely extremely important to us we could not be more grateful for this 33:17 but i'd also like to thank the shelburg foundation and even congratulate them for 33:23 their support of science in general not uh our science uh 33:28 alone or the science of the other laureates in this room um i also by the way congratulate 33:34 uh this is a time the world is going through a very difficult time now we facing the double scourge of climate 33:41 change and a pandemic where knowledge and science is more important than ever so what the 33:47 schobaric foundation is doing uh is extremely important uh at a at a key 33:53 moment a very noble thing that this foundation has done so uh uh thank you very much to the foundation 33:59 for doing that and also congratulations for having this visionary generosity to 34:05 to to go this way i also like to thank all the many colleagues in my lab who have contributed their work over the 34:12 last 30 years um too many to name i'd like to name them all but they're just too many uh to name 34:18 i'd like to also support all the institutions which supported me my my institute my university uh the 34:25 country of switzerland who has supported my research extremely generously 34:30 and last but not least i'd like to acknowledge my family who despite my 34:35 my absences both physical and and and mental uh have 34:41 have supported me they they there's an expression behind every successful woman behind every successful 34:47 man there is a surprised woman and in my case i'm lucky to have three 34:53 surprised women this is my family my wife sabine my daughter zoe and my daughter leia so many thank you to 35:00 everybody and of course the shelbert foundation [Applause]