Stress and Health: From Molecules to Societies

good afternoon and welcome to the Florence Mahoney lecture in the directors Wednesday afternoon lecture series I'll just very briefly introduce the the history of Florence Mahoney then have a privilege of introducing Francis Collins who will in turn introduce our speaker today Florence Mahoney was an extraordinary woman who was remarkably influential in political circles and directed that severe of influence in support of NIH over years Florence died in 2002 at the age of 103 up until the very last she was intensively interested in this lecture series in her name she was adamant that we should focus on only hard science and none of the scribble of stuff and I think we should be she'll be absolutely delighted with our choice of speaker today I only want to read one one quote about Florence Mahoney and published in a biography jack valenti who is a friend of hers and was an advisor to the Johnson administration said when I would tell him the president that Florence Latin that Florence Mahoney and Mary Lasker who worked together wanted to see him the president would groan he'd say oh my god these two women are going to bankrupt this country they usually got what they wanted out of him and we applaud Florence Mahoney we look for future champions in this direction and in that very same mode it's my privilege to introduce the director of NIH Francis Collins Thank You Richard good afternoon to all of you it is my privilege to introduce the speaker for this year's Florence Mahoney lecture and it's wonderful to see such a full auditorium I think that indicates that maybe people at NIH are interested in stress I'm sure I don't know why we are fortunate today to have a speaker a scientist of considerable renown who is as close to the holistic model as one could hope I think to encounter in terms of the way in which his own research includes detailed analyses at the cellular level on the expects the effects of stress on individual neurons all the way to understanding how stress affects individuals and social groupings in the work that he has done in East Africa studying baboons and I'm hoping he's going to tie that all together into a package that will elevate all of our understanding of this important aspect of what it means to be alive and how stress plays out in various ways in terms of health and disease dr. Spolsky has a distinguished academic record he's currently the John a and Cynthia fry Gunn professor of biology neurosurgery and neurology at Stanford he obtained his PhD in neuro endocrinology from the Rockefeller University he was previously a MacArthur Fellow he has received many awards that I won't even try to name but it's quite an interesting group looking through his CV I encountered hundreds of publications in distinguished places I can't help but say I also found it kind of enjoyable to get to the end of his CV and see a special category called op-ed pieces book reviews preface --is and articles in embarrassing places and I'm not sure which ones were supposed to be the embarrasing places there's a lot of USA Today and some San Francisco Chronicle I suspect maybe it was item 16 from 2002 in men's health entitled guerrilla dating tactics you can ask him about that later so please join me in welcoming dr. Robert Sapolsky well you see the drawbacks of being honest on your CV so take that as a cautionary note well I'm delighted to be here and thank you for the invitation and it's always very good to speak at a Aging context and honor someone who lived to 103 so I'm hopefully going to pick up some sort of pheromones from Florence Mahoney or maybe not maybe that's the wrong way to state it anyway but starting off I know many people here and based on that I am willing to sort of extrapolate a bit and bet that nobody in this room has leprosy I would guess nobody here is going to be running to the bathroom every 10 minutes because of their dysentery probably nobody here is teeming with liver parasites the size of your fists probably nobody here is a normal mammal you don't worry about smallpox scarlet fever a few of us come down with malaria during the rainy season few of our mothers died in childbirth nobody in this room is malnourished we're not like normal mammals we don't die like normal mammals run-of-the-mill off-the-rack mammal what happens you drink some contaminated water and you're dead two days later from dehydration what do we do we spend 75 years having our bodies go to hell on us and this is wonderful news this is wonderful news because we succumb to westernize disease diseases of slow accumulation of damage and when you look at the ones that do us in these are very different diseases than the ones that got our ancestors a world now where we live well enough and long enough to fall apart with cardiovascular disease and diabetes and cancer and neurodegenerative disorders and this is an extremely different world of who is healthy and who's sick 20,000 years ago you're some hunter-gatherer you have screwed up big time you've just eaten some reedbuck riddled with anthrax and the Medical Outcomes absolutely clear you've got like a three-day life expectancy these days you've screwed up because you've decided a diet of red meat and saturated fats and maybe a drink every other day or so constitute two healthy diet and it's not at all clear what the outcomes going to be you may be dead in your grave at 50 or you may be running marathons with your grandkids when your five and in lots of ways the central question in westernized medicine these days is why do some of us last 250 in some 285 some of it's got to do with nuts and bolts biology what your liver does with cholesterol and you know that whole world but some of its got to do with questions that nobody ever had to think about before in medicine utterly bizarre questions like what's your psychological makeup or what's your social status or how do people with your social status get treated in your society or even something as bizarre as when you're feeling unloved do you eat more carbohydrates figure that one out and you've solved half the cases of diabetes in this country this is a very different world that we've entered and when we look at these diseases that do us in these diseases of slow accumulation of damage these are predominantly diseases that can either be caused by or be made worse by stress most of us in this room will have the profound westernized luxury of dropping dead someday of a stress-related disease nonetheless it's a good thing that this happened later rather than sooner what I'll be focusing on today is what is by now a 67 year old literature showing how stress could adversely affect your body pathogenic processes all over the place we're perfectly comfortable by now with the notion that stress can do bad things to your blood pressure and your stomach walls and your gonads all of that what I'll be focusing on is what is now a 20 30 year-old story showing that in addition stress can have some very adverse effects in the nervous system even down to the level of neurotoxicity what I'll do is focus on what we understand now to be the cell molecular biology of how things go wrong and just when one is about to think perhaps this is only bad news for cultured neurons showing the increasing evidence that this is in fact pertinent to our own human brains okay at that point if you're still awake you should be depressed as hell because there's nothing but bad news between now and then what I will then focus on is a very reductive realm of potential good news the capacity to do a rational intervention in the life of the neuron the possibilities of doing gene therapy in order to save neurons from these adverse effects of stress finally in the last third what I'll focus on is a much more integrative level getting at the shear issue of why do some of us succumb to stress more readily than others and using as you'll see a rather unlikely study subject ok so starting off stress when same stress not meaning some sort of undefined state but rather a class of stress hormones that will be the villains throughout glucocorticoids adrenal steroids released in response to stress human version hydrocortisone also known as cortisol rodent version of great significance to the bad news to come many millions of prescriptions written each year for synthetic glucocorticoid such as prednisone dexamethasone and what we have classic neuro endocrine Cascades something stressful occurs the brain mumbles to the pituitary Mobile's to the adrenals and outcome glucocorticoids glucocorticoids are the damaging hormones in the story and 25-30 years now in to this finding you sit down your basic endocrinologist and they think this is the most ridiculous thing they have ever heard because if you don't have glucocorticoids you are dead they are essential for life where do they get off damaging your brain cells and to begin to appreciate that what you need to do is get a sense of what glucocorticoids are doing because they absolutely encapsulate the double-edged sword of the stress response what you do with glucocorticoids and the other players in the stress response what you do with it is exactly what your body needs done if you are getting stressed like a normal mammal you or a zebra a lion is left out ripped your stomach open your energy dragging in the dust and you still need to get out of there and glucocorticoids are essential to this process they mobilize energy delivering energy to your exercising muscles diverting it from fat from glucose breaking down glycogen breaking down triglycerides you increase your cardiovascular tone increase that glucose and oxygen levels in your bloodstream as fast as possible get it to your thigh muscles in two seconds instead of three you're that much more likely to survive during stress as well you turn off all sorts of long-term building projects in the body and this makes perfect sense if there's a tornado d this afternoon you don't spend the day outside gardening you don't worry about the long term projects until you know there's a long term you shut down digestion if you are the lion chasing after a zebra you don't have a full stomach if you receive a running for your life the energy you're mobilizing this first line is happening in like two seconds through your fat cells digestion is slow it's expensive it takes forever you're trying to avoid being somebody's lunch don't worry about digesting breakfast and we all know the first step of this suppose you get a little bit stressed speaking in public what happens your mouth gets dry you've stopped secreting saliva the first step of shutting down the system in addition you shut down growth you shut down reproduction big expensive optimistic things to be doing with your body and this is no time for it you're running for your life there's a line two steps behind you you know ovulate some other time don't do it right now hit puberty next we grow antlers tonight doting to think about sperm hallmark of the stress response you shut down growth you shut down tissue repair every sex hormone on earth disappears from the bloodstream do it later if there is a later continuing all the way down to stress hormones glucocorticoids getting into the brain and short-term they do wondrous things they sharpen cognition they lower your sensory thresholds flashbulb memory thee where were you every one of us in this room will remember forever exactly where we were when we heard the news that Britney Spears had shaved her head so you need some sort of mechanism saying this is important file it away look at all the stuff you're doing here on the Left you're mobilizing energy you're delivering where it's needed you're shutting off the uh essentials you're thinking more clearly absolutely essential if you were going to be a normal mammal being normally acutely physically stressed and glucocorticoids are central to this what you see on the right though is what if you secrete them too often too long for purely psychogenic reason psychosocial ones and we see a whole array of the pathologies of and excess of stress and excess igloo corticoids not coincidentally some of the leading causes of disease of westernized lifestyle so we have this double-edged sword if you plan to be stressed like a normal mammal you had better secrete glucagon cause if you are going to be stressed like a cognitively sophisticated primate like us which is to say chronic psychosocial stress glucocorticoids are bad news now it's in that context that we can appreciate this last line this ability of chronic Luca corticoid exposure to begin to damage the nervous system and again this is a literature going back in decades you disrupt the sort of memory specialized by a part of your brain the hippocampus explicit declarative memory chronic stress chronically corticoids it's impaired and all the building blocks of it are as well non neurobiologist LTP is long term potentiation it's probably what's going on between your synapses when learning occurs essential in the hippocampus glucocorticoids and stress disrupted over the course of days to weeks in rodents stress glucocorticoids causing retraction dendritic atrophy disconnecting circuits probably the biggest revolution in neurobiology for the last 2,000 years if you took an intro neuro class they taught you the adult brain doesn't make new neurons that is not the case it is centered in the hippocampus in response to learning exercise stimulation and the surest way to shut it down stress and glucocorticoids finally as I'll be focusing on the ability and an extreme of glucocorticoids to overtly kill hippocampal neurons or to endanger them to make them less capable of surviving a neurological insult so the question becomes where do these hormones get off damaging your hippocampus why the hippocampus and this was appreciated in the late 60s work of Bruce McEwen and colleagues Rockefeller University who mapped the first steroid hormone receptors in the brain and as I understand it virtually by random he started with glucocorticoids and back came autoradiogram like these reaming the hippocampus the target site for glucocorticoid action and from that day on if you're going to think stress and the brain and glucocorticoids you got to start with the hippocampus over the subsequent years emerged a picture of glucocorticoids being able to damage the hippocampus and every one of these slides is a dozen years work from various labs but a literature coming out then showing lots of stress lots of glucocorticoids and you make a hippocampus get older faster more dead neurons more reactive gliosis more of the associated memory problems conversely go in there and any of a number of different techniques decrease the cumulative glucocorticoid exposure and you slow down the hippocampal aging and you put the pieces together of cumulative glucocorticoid exposure over a rat's lifetime a very dramatic pacemaker of the rate of hippocampal aging ok so how does this work how are these glucocorticoids killing hippocampal neurons and it struck me in the mid 80s or so that in fact glucocorticoids didn't need to be killing hippocampal neurons all they needed to be doing was messing them up in some way all they needed to be doing was taking a hippocampal neuron and leave it dangling on the edge of some cliff at that point if nothing else happens everyone lives happily ever after on the other hand if at that point you push the neuron with something else it's that much more likely to go over the edge and what this notion of endangerment predicted was all sorts of neurological insults the damage that hippocampus should be made more damaging when there's a lot of glucocorticoids on board and this turned out to be a case with a vengeance all sorts of the leading necrotic insults to the hippocampus the more glucocorticoids in the circulation at the time the more of an acute stress history the more dead neurons afterward ischemia stroke hypoglycemia sustained seizures oxygen radical generators of great disturbing relevance the beta-amyloid peptide the rogue peptide and Alzheimer's disease gp120 the glycoprotein from the AIDS virus responsible for some aspects of AIDS related dementia what we got here are an enormous Lee very number of ways of doing in an Iran all of them made worse by glucocorticoids whatever this cliff of vulnerability is about it's a very generalized one so what is it about what's going on here what you then begin to see is all sorts of possibilities how our glucocorticoids doing this they could be changing cerebral perfusion rates and insulin levels and 11d different things in the periphery the surest way to show that it's not a phenomenon of the peripheral physiology is get rid of the peripheral physiology do all the same thing in vitro in vitro models of these insults and you see the same thing insult and the more glucocorticoids on board the fewer surviving neurons and using these in vitro approaches you could do your basic endocrine homework and ask for example do you see endangerment by glucocorticoids like this in other brain areas cultures from cortex hypothalamus cerebellum you do see it in other areas nowhere near as dramatically as in hippocampal neurons this is the most sensitive area second question what about other steroids what about specificity do you see endangerment by progestin Xandra jhin's no not at all how about estrogen of great relevance to about 30 minutes from now not only does estrogen not make things worse estrogen is protective we'll come back to that finally for those who care about such minutia there's two different types of receptors for glue corticoids it's the GR that mediates this this is classical boring and de chronology this is a hormone working in a specific way through its receptor so that whatever you now throw at the target cell it's going to be in a more fragile state so what is this about how are glucocorticoids in danger and it struck me about the late 80s or so that there is one thing in common that slide I just showed you all those different neurological insults so heterogeneous they all ultimately have one thing in common which is they ultimately constitute an energy crisis either the neuron can generate enough energy hypoglycemia hypoxia schemee or the neuron has such insanely high energy demands sustained seizure that there's an energy crisis so looking at that that struck me that maybe what this generalized cliff of vulnerability is about is in some way an energetic one now what this predicted was a very simple experiment which is you should be able to take one of these insults that causes like this much damage now insult plus glue corticoids you get this much damage insult glucocorticoids and feed the neurons something extra supplement them with excess energy and you will subtract out the glucocorticoid endangerment and that's precisely what you wind up seeing all sorts of ways of demonstrating this here just one version a particular insult insult alone this much hippocampal damage in so plus glucocorticoids far more damage insult glucocorticoids and feed the neurons man owes man owes this monosaccharide it has its own transport system in the brain works perfectly well away goes the endangerment try the same thing with fructose no luck doesn't capacity blood-brain barrier use one of the only other things neurons can eat ketone subtracts as well it's an energetic endangerment so by the early 90s we had figured out the mechanism for this and his neurobiologists we were thrilled because we were one the first to see this and his endocrinologist we were totally bored because everybody had known this forever it's got something to do with the logic of what you want to do with your circulating glucose when you're stressed you're running for your life from the lion you've just done gluconeogenesis and your liver you've dumped glucose and your blood stream for your exercising muscle what would be the stupidest thing on earth now to do with your circulating glucose store it away in your fat cells for next spring store it away in your liver stored anywhere and for 56 years it's been known glucocorticoids inhibit glucose uptake and storage throughout the body except for exercising muscle a strategy for diverting it to where it's needed so we went and looked and in the hippocampus the exact same thing glucocorticoids inhibiting glucose uptake by way of pulling glucose transporters off of the cell surface less glucose uptake at that point is this a big effect not at all take a fat cell and glucocorticoids new knock out like 80% of glucose transport do it with a neuron via knockdown maybe 20% that's not enough to kill under on but you're not trying to explain killing a neuron you're trying to explain making it a little bit queasy and fragile and what you see then is along comes an insult and with glucocorticoids ATP levels drop sooner mitochondrial potential collapses faster you have a neuron that is more energetically vulnerable at this point so what goes wrong at this point and I put up here this magnificent 3,000 year old Egyptian hieroglyphics showing the synapse which I do need to replace one of these days but what we see here is the basic workings of excitotoxin necrotic neurological neuron death the centerpiece of all of that being the release of a class of neurotransmitters excitatory amino acid neurotransmitters most notoriously glutamate glutamate if you want to learn and do that LTP stuff you better release glutamate in your hippocampus but all these insults involve a vast excess of glutamate causing tidal waves of calcium mobilization causing downstream generation of oxygen radicals and cytoskeletal breakdown and all sorts of bad stuff all of those neurological insults involve this pathway tremendous amount of work at blocking various receptors chelating calcium this is the central dogma of acute necrotic neuron death critically every step in this pathway is made worse if you're running out of energy at the presynaptic end the neurons are more readily depolarizing they dump more glutamate even more importantly they don't have the energy to run these high affinity reuptake pumps more glutamate sticks around longer more calcium rushes in and not enough energy to pump them out and what you see is all of these steps are energy dependent now at this point you don't need to be a brain scientist to come up with a scenario that ooh insofar as glucocorticoids make all of these energy dependent insults worse in an energy dependent manner maybe what they're doing is by inhibiting glucose uptake the neurons are simply less capable of doing every step along the way and in this badly doctored hieroglyphic here was the 90s in my lab showing this is precisely what occurs every single step is made worse with glucocorticoids on board more glutamate sticks around longer more calcium sticks around longer more of all the downstream steps all of them reversible with excess energy so in lots of ways that's kind of where the story is at this point Luca corticoids hammering away at these neurons making them more fragile neurons however do not just sit there and get pummeled by these insults there's a variety of defenses they can mobilize they up regulate heat shock proteins antioxidants there are retaliatory neurotransmitters that inhibit glutamate release there's a whole bunch of these defenses collectively they're somewhat protected collectively they're really expensive and thus you know the next sentence I'm going to say not only do Glu corticoids make the insults more insulting they impair the capacity of neurons to mobilize these defenses so that's where the story is at except for one complication and this is one that is always floated around if you're oriented towards the world of neuron death a dominating theme these days is inflammation unhappy brains have chronic inflammatory States inflammation plays a big role in the neuron death after both acute insults and slow neurodegenerative diseases in a broad sustained way big time inflammation bad news in the brain glucocorticoids and inflammation glucocorticoids are anti-inflammatory everyone learns that in kindergarten glucocorticoids are anti-inflammatory thus glucocorticoids should be decreasing damage not making things worse and for about 15 years sort of my next to last paragraph my ro1s would always hand wave like crazy on this one saying well insofar as you have glucocorticoids making things worse for the neurons but decreasing the inflammation ooh you got the arrows pointing in two different directions which arrow is stronger put the pieces together in a whole system and if you've got more dead neurons coming out the other end it means the endangering component is more powerful then about a half dozen years ago I had a first-person my lab and immunologist decide actually look at this to finally explicitly show that yes this arrow isn't as powerful as this one and something very interesting came out instead something that has now been seeing a number of labs which is there's all sorts of domains in the acutely injured nervous system where not only are glucocorticoids no longer anti-inflammatory they can worsen inflammation they are pro-inflammatory and this has now been shown my group on a number of different levels glucocorticoid stress increasing the amount of inflammatory cell migration to the injury site more production and release of inflammatory pro-inflammatory cytokines a absolutely textbook thing the glucocorticoids do is inhibit the activity of NF kappa-b pro-inflammatory transcription factor what they do in the injured hippocampus and cortex is they increase the activity of NF kappa-b this whole pathway here exacerbated and we're beginning to believe what it involves is oxidative damage to a cofactor of the glucocorticoid receptor which changes receptor interactions with NF kappa-b and for us most remarkably is one inch away in the rest of the brain classically anti-inflammatory so this is a new disturbing piece of the story ok so all sorts of this is bad news bad news for rats for mice for cultured hippocampal neurons what about us what about the primate brain now the primate brain has the hippocampus even though it's spelled differently in the primate but up until a number of years ago about a decade ago the entire literature of asking well is this pertinent to the primate hippocampus the human one consisted of a number of studies that came out of my lab looking at captive primates and showing sustained social subordination stress and you get the same thing as in the rodents you get hippocampal damage at the e/m level same exact picture oh one would conclude this may be a bad sign for stress then follow-up study surgically implant cortisol secreting pellets in the hippocampus and monkeys come back a few years later same bad thing the suggesting that maybe all this bad news is in the ballpark of impertinent to humans in the last 10 years or so what's become clear is it is far closer than merely on the ballpark a number of different bodies of evidence three of the strongest now Cushing's syndrome Cushing's most will know any of a number of disorders resulting in wildly elevated glue corticoid levels you get every pathology on the right side of that chart back when including memory problems hippocampal dependent memory problems often known as cushingoid dementia and about a decade ago Monica Starkman and colleagues University Michigan showing atrophy of the hippocampus only the hippocampus and Cushing's the more elevated the glucocorticoid levels the more atrophy the more memory loss bad news is this due to dead neurons almost certainly not because what they then show who's go in and surgically get rid of the tumor and over the next year or so hippocampus comes back to normal volume and cognition normalizes next one PTSD post-traumatic stress disorder combat vets childhood abuse and by now an extensive well replicated literature showing atrophy of the hippocampus preferentially so the more severe the trauma history the more atrophy the more memory problems is this one reversible as far as I know from the literature no but that may well be because PTSD actually is never cured people learn to manage it a huge incendiary question in that field right now is whether trauma causes a tree of the hippocampus or whether a small hippocampus sets you up for being more vulnerable to trauma at least some of the evidence shows that trauma can lead to hippocampal atrophy finally of alarming pertinence - like 15% of us in this room those of us destined to have a major league depression at some point or other depression and about half the patients associated with highly elevated glue corticoid levels and a literature now showing atrophy of the hippocampus the more severe the depression history the more atrophy the more memory problems and at present the bulk of those studies show that when the depressions have been normalized you do know get normalization that they hit the capital volume okay so it was promised you should be utterly depressed by now okay let me make it even worse more bad news so what does this tell us also about the hundreds of thousands of individuals getting high-dose corticosteroids each year for their rheumatoid arthritis their lupus all of that too they get memory problems well-documented steroid dementia and the first good case control studies are now showing that for the same inflammatory disease the more of the history of treating it with steroidal anti-inflammatories rather than non-steroidal the more cognitive problems finally what this also is telling you is if you go and have yourself a stroke please mention to your clinician not to give you corticosteroids at that point typically done at that stage and something lead less than leading medical institutions in this country to take down the post stroke edema and it's been clear for thirty years that it doesn't do a very good job of taking down the post stroke edema and it tends to worse than the neurological outcome so the best people in the field for decades have been saying don't use steroidal anti-inflammatories for post stroke edema use nonsteroidals more evidence supporting this but the worst news in some way is go and have one of these neurological disasters and you don't need your neurologist to give you google corticoids at that point to get into trouble you're secreting boatloads of the stuff on your own somebody who has just had a concussive head trauma grand mal seizure cardiac arrest some of the highest levels of glucocorticoids you will ever see in a mammal and they make the damage worse how do you know take a rat and adrenalectomy is it right after one of these insults and there's less damage afterward in other words what we've been taught to think of as the typical damage you get after these insults in the hippocampus is damage we've made worse by the fact that our bodies stupidly go and have stress responses at the time I mean look at how bizarre this is you get chased by a predator you secrete glucagon jitu your thigh muscles saves your life psychological stress you're on a blind date you secrete glucose and divert energy to your thigh muscles probably irrelevant you have a stroke you have a stroke and you divert energy to your muscles totally maladaptive this is very very useless from the neurological standpoint so what can you do about this obviously you can't adrenalectomy somebody just because they've had a seizure but all sorts of things can be done there's a whole class of drugs well documented well studied in various endocrine clinics for years used in other domains that are steroid Genesis inhibitors and they will shut down blue corticoid secretion for 12 24 48 hours or so and my lab and other showing get it into the animal right after the insult stop the glucocorticoid secretion you decrease the damage but what if you're too late for that and you've secreted the hormones already next obvious option is get a glucocorticoid receptor antagonist block the receptors and the very renowned progesterone receptor blocker ru-486 is also quite good at blocking glucocorticoid receptors a literature now showing that can be protective as well but what if you're too late for that they've already bound to their receptors they're already messing up energetics and what you see here is a strategy showed earlier energy supplementation but what if you're too late for that and you're already now in the realm of more glutamate and more calcium more oxygen radicals and you have now entered the central arena of neuron death and what I put here is not facetious but the transition instead to the next section go and build yourself a better neuron and from the early 90s the main focus in my lab has been doing so with gene therapy strategies okay at this point it's not hard to come up with a shopping list of what sort of genes you might want to over express in a neuron going through one of these acute insults what of course has always been the challenge is how are you going to do it for the very simple reason that the gene therapy techniques that like you could do in your liver that are so easy like high school kids doing for science fair projects you can't use any of that stuff in the nervous system because the brains heterogeneous in the brain isn't accessible most of all because the brains post-mitotic and neurons most of the viral approaches retroviral ones are taking advantage of cell division what you're left with is a relatively small family of neuro trophic viruses that are able to infect non-dividing cells and since over these years my lab is focused on using a number of these to deliver the genes in question okay so starting at that time early nineties what genes would we want to over express and starting off right then the first gene we chose not very surprising was one that focused on everything that goes wrong on all of these insults again no matter what the acute insult is a little bit of extra energy is going to help so the first one starting with over expressing the glucose transporter so how do you show this is useful first you do your basic molecular homework can you find a vector that's safe does it express is the protein made does the protein wind up in the right place you do all that good next step if you're over expressing a glucose transporter you'd better be able to show that these are neurons that now take up more glucose and you can show this in vitro in vivo sort of controls in vitro either mock infection or infection with a vector only with a reporter gene showing us in vivo to deoxy glucose mapping great neurons are taking up more energy if you've gotten that far you now better be able to show that these are neurons that are happier metabolically all sorts of ways of showing this here's one version and a technique called silicon micro fizzy amah tree measuring metabolism of cells in vitro in real time throw in an insult metabolism crashes throw in an insult overexpressing glucose transporters and you buffer metabolism so if you've gotten that far what you better now be able to show is these are neurons better able at handling the glutamate and the calcium in the oxygen radicals and absolutely that overexpress glucose transporter and less glutamate in the synapse less calcium mobilized and if you've gotten to that point what you better now be able to show is fewer dead neurons in vitro models in all these cases in vivo taking care and taking advantage of reporter genes showing the more neurons infected the smaller of a lesion that's great one additional thing you need to show though which is most of us are not going to have the luxury to schedule our stroke for next Tuesday afternoon the doctors got an opening if this stuff is going to work it's predominately going to have to be done after the fact what sort of time window do you have and this is explored here introduced overexpression of the glucose transporter at the time of an insult you decrease the damage this is stroke model in first introduced it a half-hour post insult protection one hour by four hours the window is closed just getting a sense of what sort of time period you got to work with so over these years we have now worked our way up and down various pathways of neuron death 20-25 different genes asking does it protect against this insult that one do we understand the mechanisms what's the time window afterward for expressing different of these genes okay so all of that under our belt we then began to be able to think about doing gene therapy against stress gene therapy against the actions of glucocorticoids now the first thing we wanted to do was be able to have a vector system that would only express during stress a stress inducible system and what we began to think about then was a very clever bizarre thing that herpes virus which is our main vector system that we use that herpes virus is able to do we all know this you get a herpes infection you get a flare-up it goes away and then it goes latent for a month or 50 years and then at some point it comes out of latency when do you get a herpes flare-up when you were under stress under stress like bereavement like divorce like and like chemotherapy like social subordination new rodent all of those bring viruses like herpes at a latency what's the logic there chronic stress immune suppressed great time to come out of lace latency make a bunch of new copies myself and then go hide again it's a very opportunistic thing that viruses like these have evolved so thus you have the question how is herpes virus able to know that the host organism is stressed and a few years ago a Harvard group got the answer to this okay mechanism of action to glucocorticoids steroid hormone enters target cell binds to steroid hormone receptor at which point it translocates to the nucleus and Bynes in this case glucocorticoids to a glucocorticoid responsive element glucocorticoid response a promoter and it does its transcriptional thing at that point what do these folks find herpes virus is able to measure your glucocorticoid levels it's got GREs all over its genome all of its genes of reactivation out of latency have GREs upstream of it it knows when you're stressed so we took one look at this and like wet our pants we were so excited we immediately like made our vectors and stuck in a half dozen of these GREs and sequence there and what we wound up getting was a stress corticoid inducible vector system in what you've got here endogenous glucocorticoid synthetic ones and not by the other steroids dose response matter another hieroglyphic here in vivo increasing circulating levels of glucocorticoids more induction of this vector finally a sustained seizure model massive induction of this you can use the system to decrease hippocampal damage after these insults a stress inducible system now what we then began to focus on was what kind of genes we would want to express driven under circumstances of stress and we made a family of three genes at this point one over expressing an enzyme that breaks down blue corticoids one expressing a trans dominant mutant version the glucocorticoid receptor the one most pleasing to me is on the bottom okay back to 30 minutes ago that business about estrogen not only does estrogen not make things worse estrogen is neuroprotective in all sorts of domains estrogen being a steroid hormone works the same way as GU corticoids estrogen binds to estrogen receptor translocates to the DNA to an estrogen responsive element and then having beneficial transcriptional effects so what we did was go and make ourselves an artificial gene that was half of the glucocorticoid receptor and half of an estrogen receptor the hormone binding domain from the glucocorticoid receptor the DNA binding domain from the estrogen receptor what happens along comes a stressful period binds the glue cord Boyd's and then translocates to the estrogen responsive element instead of the glucocorticoid responsive one and this winds up transducing an endangering glucocorticoid signal into a protective estrogenic one one example of this be Deanna the growth factor all you need to know about BDNF is it's a good thing you want to have a lot of it in your hippocampus stress drives down the levels of the glute corticoids Drive it down estrogen boosts up BDNF levels and here we see estrogen treatment of go BDNF levels now instead here is a rat over expressing this chimeric artificial receptor and stress and it suddenly acts as if it's exposed to estrogen so here being able to build not only a protective stress response that gets rid of them corticoid actions but get you something protective for free now using this approach we've now started to look at other issues not only can we use gene therapy strategies to protect neurons from neurological insults can you begin to manipulate behavior can you begin to deal with animal models of psychiatric disorders and here's one example of it now over expressing this anti-glue corticoid system instead in the amygdala if hippocampus is about learning and memory with mindless simplicity the amygdala is about fear and anxiety and what we've got here is by blocking the effects of stress in the amygdala you decrease fear conditioning you can block fear conditioning which is normally greatly facilitated by stress you can do the same thing in the amygdala and decrease anxiety rats overexpressing these things are more likely to explore new open spaces which they are normally quite averse to with chronic stress the amygdala expands remember back twenty minutes or so stress causes the hippocampus to atrophy chronic stress the amygdala expands becomes more excitable LTP is enhanced you are more fearful you learn fear associations more readily and over express these anti stress vectors and you can decrease the size of the dendritic Arbor all of that good first baby steps of something in the way of gene therapy for psychiatric disorders you could then take it one step further and forget blocking the pathogenic effects of stress can you now simply block some of the physiological but negative ones can you enhance cognition during stress by now a whole series of studies we have by manipulating the glucocorticoid system blocking glucocorticoid receptor action over expressing another type of receptor that's beneficial you can now generate a rat which instead of learning worse during stress learns better finally that issue of neurogenesis in the hippocampus as promised with glucocorticoids with stress you suppress neurogenesis and what you see instead is you push towards an oligodendrocyte phenotype when you were inhibiting neurogenesis in your neural progenitor cells in the hippocampus you push instead in that direction use one of these anti glucocorticoid vectors and you push away from the oligodendrocyte phenotype and push back towards neural reproduction in theory you could now make a hippocampus which makes more neurons during stress instead of less okay so all of this is wonderful hooray for us highly protective ism this terrific next slide is meant to be extremely sober and this is a slide that I've been putting a proudly serving in the mid 90s or so and summer a few years ago struck me in fact this was quite embarrassing putting this up this is an ex plant of human brain tissue infected with these herpe viral vectors of ours expressing a blue reporter gene and you can see little bits of blue there expressing along the margins there you can get these vectors to work in human brain tissue and 14 years later now this is still the best damn picture I've ever got to show the field is not going anywhere yet in terms of being able to translate this into clinical medicine very soon there's problems of delivery there's problems of safety of the vectors all the sorts of things that has hamstrung gene therapy and all sorts of other realms doing it in the nervous system is the final frontier in many ways this is lurching in the right direction so a little bit of good news there but good news only like at this stage have a neurological insult if you want to save three adjacent neural we can do it for you right now you want to say four neurons you're going to have to wait a while but nonetheless the field is moving in the right direction okay so back to that slide before putting up what can be done block the hormone release block the receptors block the downstream consequences there's another thing you could have put up on that chart which I fail to do because it is so idiotically obvious and simplistic that it's just absurd to put up which is ooh don't get stressed why that's terrific advice and don't get stressed what I will transition to now in the last part of this talk is looking at this issue of go finish this lecture step outside and unexpectedly be gored by an elephant you're going to have a stress response you can't psychologically reframe your experience you grow from adversity or something like that go and have a concussive head trauma you're going to have a stress response go and have any of those acute neurological disasters go and have the sort of ambiguous social interactions that we navigate every day and only some of us will have stress responses only some of us will have different less adequate degrees of coping with stress and what I transition to here in this last section is beginning to deal with this issue of why do some bodies and even more importantly some psyches deal better with stress individual differences okay so you want to study this you can study this in humans where there's all sorts of fascinating things for example findings like major depression and for many years afterward you were more at risk for cardiovascular disease very solid funding by now that's great but god help you if you've got to understand all the intervening steps between those two events there it takes forever you outlive your thesis committee it's very difficult stuff okay so instead look at these issues and rodents lab rats you know shorter life span control the stressors control the pathogens a big problem there though is if a lab rat is a good model for your emotional life you've got problems so picking something in the middle there are non-human primates that's great all the obvious similarities but what's also clear is you're dealing with captive primates the potential for distorting behavior due to the captivity is enormous so with all those things in mind for the last 31 years each summer I skip out of my lab and go and study these issues in a primate population asking who gets the stress-related diseases but studying primates in their natural habitat and for these summers these have been my study subjects these are olive baboons savanna baboons living in the grasslands of East Africa these are the baboons that live in these troops of 50 hundred animals or so and this is their habitat the Serengeti ecosystem and this is your basic sort of a Robert Redford Meryl Streep grassland mosaic plateau savanna and what you have here is something critical for what I'm trying to study if you are a baboon and you had a choice in the matter this is where you want to live fabulous ecosystem you live in these big troops so the Lions don't mess with you often you have a lower infant mortality rate than among the neighboring humans probably most importantly you only have to spend three hours a day getting your day's calories critical implication if you only have to work at that three hours a day you've got nine hours of sunlight every day to devote to being just miserable to some other baboon that's the critical thing these guys are not getting stressed by predators or malnutrition they are getting stressed by each other overwhelmingly if you were a baboon in the Serengeti and you're unhappy it's because another baboon has worked very hard to bring that state about they are perfect models for westernized stress-related diseases because like us they have the luxury of generating psychosocial stress so what is the stress about in their world you go and study these guys and within hours what's clear is not all baboons are equal there are instead dominance hierarchies a number one 1020 and the quality of life varies enormous ly it influences who grooms who it influences what food you get access to it influences your mating success to a certain degree it influences do you get to sit in the shade and the hottest part of the day do you get to sit in the highest branch of a tree when the leopards around is very important rank is a very powerfully organizing feature of their society to give you an example here's a middle ranking male who's just killed an Impala this is hot stuff this guy's about to get three days worth of protein this is wonderful and suddenly from out of nowhere along comes the alpha male and what we see is our guy picks up and within seconds the alpha male has the kill exploiting the labors of the working class and what you see here most strikingly is there was no fight there was no overt aggression the guy who left didn't even mumble dirty words under his breath when the hierarchy is stable these animals are smart enough to know their place in the society rank is a very very stabilizing defining feature of their world so you look at this and of course you wonder well what goes into being a high-ranking baboon and for reasons I can explain later if there's time 90% of my work over the years has been on males rather than females what goes in to be a high-ranking male baboon one critical feature of it is to win the right fights male baboons have huge canines bigger than an adult male lions they use them they have the highest aggression rates of non-human primates here's a male with a deep canine slash in a shoulder and this is not just ritualistic fighting this is a male who had joined a troop of mine a few weeks before and the only way of describing this guy is he had terrible political skills he was hassling all sorts of guys he had no business going near one night coalition of six of them ganged up on him and this is what was left in the morning over my thirty years the leading cause of death of male baboons are male baboons so extreme high rates of violence far more often though you get threats of violence you get conventionalized gestures like this threat yawn where it is clear what you're telling the guy and the other tree there is look you remember what happened last week I've got the same teeth as then do is both a favor and don't push your luck and most of the time they don't push their luck instead they give a conventionalized gesture of subordination so violence or threats of violence and that's all these guys were about they would be boring what they're mostly about though are things that look real familiar to us things that have to be defined as psychologically stressing each other so what is it that makes psychological stress stressful jumping over a huge literature what you see is for the same external reality we feel more stressed we activate more of a stress response we're more at risk for stress-related disease if we feel like we have no outlets for the frustration caused by the stressor if we feel like we have no control no predictability if we interpret things that things are getting worse and if we lack somebody shoulder to cry on and baboons are brilliant at manipulating these variables in each other first example here is a male baboon who is in a sexual consort ship with a female this female is in estrus and heat ovulating and he's sitting there grooming her he has been with her for the last three days and you'll notice just happening to be six feet away on the other side of the bush is another high-ranking male baboon who just happens to have been six feet away around-the-clock for the last three days never an inch closer never an inch further not fighting with the guy not even threatening him just around just constantly present just harassing the consort ship and this is enormous ly costly this guy hasn't slept in days he hasn't eaten what you wind up seeing is almost half the time this guy will pick up and voluntarily relinquish the concert ship to this guy this is not violence or threats of violence this is grinding psychological stress next version here we have one of the wild card strategies for a male baboon which is get yourself a coalitional partner to back you up in a fight and if you've got one you can rely on this is really great and you can be unstoppable at that point and here we see two of these coalition's facing off and if you don't know baboon body language these are for very uptight baboons and what's clearly about to happen is violence about to break out in a second later yes indeed the fighting begins the bet anybody see the fourth baboon there is there is showing this close relative ours which is when the going gets tough you bail out of there about 40 percent of the time when the fight occurs your erstwhile partner bails out on you and of the times that he does a third of the time he joins the other team talk about psychological stress you go into a fight that's life-threatening and you don't even know who's on which side here we have a male again in a sexual concert trip with this female grooming her and in this case he's being harassed by this guy high intensity a foot away threat yawning him in his face this guy in the middle is under stupendous pressure you know he is going to crack he's going to become violent and a second later yes indeed he does he spins around and he bites the female oh another feature of this close relative ours which is when the going gets tough look at somebody smaller to take it out on about half of baboon aggression is third-party aggression dumping on an innocent bystander a male loses a fight chases the sub-adult who bites a female who slaps a juvenile who lunges at an infant what does this mean you're sitting there minding our own business bird-watching and some other guys having a bad day and as your rear end they get slashed lack of control lack of predictability so looking at all of these traits what goes into being a high-ranking individual in this sort of world yes being big and muscular and big canines and all that sort of thing but also all sorts of social intelligence stuff which coalition's you form which ones you don't go near impulse control which provocations you could ignore as opposed to getting into every fight that eventually leaves you crippled and starting with these guys in the 70s it struck me watching them another feature of this was successful males in the world like this will have bodies that deal well with stress and that's what I proceeded to go and study and what I'll show you is I then wasted my next 15 years studying that because it turns out that was a stupidly simplistic question to ask because there's something much more interesting happening okay so how do you study this what does your social rank have to do with your stress physiology part of what you do is your basic Jane Goodall sea and of collecting behavioral data but what you also then have to do is get physiological data out of these guys with all sorts of constraints and this is a frame from a PBS thing a few years ago and you could see in this frame a white flash there on this guy's shoulder a blowgun Dart exploding at that point all sorts of constraints you got to get an anesthetic that doesn't mess up the hormone you're trying to study next you got a dart everybody roughly the same time a day in season to control for rhythm isset e next if you're trying to get a first blood sample out of the guy that tells you something about nice resting levels of stress hormones you can't dart somebody if he's had a fight that morning if he's injured if he's sick if he's made it you want to look at cholesterol you can't get somebody if he's had breakfast yet that morning next constraint you can't dart somebody if he knows it's coming there can't be any anticipate or e stress so you can't just get in your Jeep and chase the guy around for three hours and when he's winded you suddenly nail him final constraint if you want to get that first basil sample you've got like one to two minutes from the time the anesthetic kicks in to get a first sample out of the guy so given all those constraints about once a decade it works flawlessly and you've got an S the thais baboon at that point you take blood CSF tissue biopsies you can have a fancy heparin lock syringe on your acacia branch you get all your samples their samples are processed on a hand-cranked centrifuge which is as awful as it sounds guy recovers overnight in the cage let them go the next morning to his buddies get your dry ice shipment once every two weeks keep your samples frozen sneak them through customs and you're all set okay so given this what if I looked at over the years what's going to be the first thing I look at what's the relationship between rank and glucocorticoid levels and by now you can absolutely define the perfect profile what do you want absences stress you want like a zero glucocorticoids in the bloodstream along comes a psychological stressor don't get suckered in by it keep the same low levels along comes a real physical stressor have the biggest fastest response possible and the second is over with have the biggest fastest recovery you can get and that's exactly the profile that you don't see if you're a low-ranking baboon everything in them is worth basal levels of glucocorticoids are elevated they're elevated even the absence of stress because if you're low ranking you're always stressed you spend two minutes digging some food out of the ground anybody can rip you off you spend the whole morning getting somebody to groom you anybody else can disrupt it you're sitting there you get your rear end slashed by somebody else lack control lack of predictability lack of outlets when a real stressor finally does come along subordinate guys have a sluggish stress response when it's over where they have a sluggish recovery exactly what you don't want to have and I then spent the next dozen summers out there sort of doing circuitry on these guys trying to understand what's working differently according to rank at the level of brain pituitary adrenals that accounts for these elevated glue corticoid levels and subordinate baboons and mechanistically what you turn out to see is you get hypercortisolism and a subordinate baboon for the same exact reasons that you see elevated glue corticoid levels in a human with major depression cognitive psychology sound buy depression is learned helplessness and lots of ways being a subordinate baboon is an adventure in learned helplessness okay so using this approach working up and down all sorts of different physiological systems and you always see the same thing it works completely differently depending on your rank and consistently it's the low ranking baboons who are more set up for stress-related disease so this seems really straightforward which is you know go out and be a big high-ranking baboon and fight and win win win and one big social darwinism blow out there let me spend the last couple of minutes there showing how this is totally wrong and how there's much more interesting stuff going on that is much closer to home yes your social rank is important but first qualifier far more important is the sort of society in which this occurs one example among many all the data I just summarized for you come from hierarchies that are stable what do I mean by stable number five wins 95% of his interactions with number six number five loses 95 remember his interactions with number four they're stable diets on the other hand if five is winning only 51% with number six they might be just about ready to flip their to the other way that's an unstable diet all the data I showed you come from seasons were more than 90 percent of the interactions reinforce the status quo every now and then something happens some critical male dies is injured leaves the troop joins the troop who knows what and something destabilizes and the hierarchy completely comes apart for three months high-ranking guys are still higher ranking than the lowest ranking but among the highest ranking cohort it's chaos everybody's fighting nobody's mating nobody's eating the trains don't run on time enormous amounts of conflict there eventually it settles down what we see here is high ranking males during a stable period nice low basal goo corticoids same males of same average rank during an unstable period and the advantages go down the tubes it's not being high ranking it's being high ranking in a stable hierarchy because you've got all the psychological advantages there be high ranking be in the Czar's palace while the revolution is happening at the gates that's not a very good place to be when the hierarchy is unstable it's the highest-ranking individuals who now show the worst health so it's not just your rank at what it's what the rank means next it's also how you personally experience this two examples actually interest of time one example ok this was some years ago an extremely aggressive male joined the troop who no doubt try to impress the other male spent all of his time attacking there is females and two weeks after he joined the troop I was able to keep track of how many times had females been attacked by him to the point of his blowing drawing blood ranging from females who were lucky and those who were attacked most frequently then I darted a whole bunch of these females and looked at their white blood cell counts just Neanderthal immunology but the best that could be done out there and what you see here is a dose-response relationship the more often they were attacked by this guy the more immunosuppressed they were here were white blood cell counts and the females before the guy joined the troop so you say ooh what are the effects of a destabilizing aggressive male in function female baboons the answer is it depends it depends on your personal experience of it if you're lucky enough to be sitting on the sidelines it has no effect whatsoever it's not the abstract state of being in a violent Society its how often is your own personal nose being rubbed in it final variable and this is the strongest one yes rank is important as well as its meaning as well as personal experience but most important probably is your personality with which you filter all of this now twenty years ago if primatologist said the word personality they would instantly have their tenure taken away this is now the hottest term in primatology non-human primates have stable long term differences in temperament and a number of years ago what I did was sit down with 15 years of behavioral data and try to come up with every personality marker I could think of in these baboons you anthropomorphize like crazy what's a baboon's equivalent of a hobby what's a baboons you know smiling on the right side of the street all that sort of thing came up with like 50 measures control for rank control for stability of rank ran it against the physiology and out came an interesting finding which is all of the good physiology you get if you are a high ranking male and a stable hierarchy has nothing to do with being high ranking it is all due to some personality styles that tend to go along with high rank and you could be number one on the trubin if you don't have any of these styles you're going to be just as hypercortisolism here becomes what personality style works for a baboon and given that arm from San Francisco I could spend my weekends in like marine giving hot tub seminars to baboons teaching them how to manage stress by being exactly this way how does a male baboon go about competing with other males first variable can you tell the difference between threatening and neutral interactions in the world what does this look like you got a male he's sitting there his worst rival on the whole planet shows up and threatens him in his face from foot away this is bad news what do you do what do you do you stop what you're doing you take this defensive vigilance that's sitting there worst rival on the whole planet shows up and takes a nap a hundred yards away what do you do you do whatever you were doing this is not a big deal pathetically your average male baboons is not behaviorally distinguished between being threatened in the face by his rival and his rival napping it makes him just as disruptive this behavior this is type-a personality this is sitting there saying like look at that guy I hate him and look at the way snoring he does not just dig into my nerves this is seeing stressors that other individuals don't after controlling for rank if your behavior is just as disrupted by your rival sleeping is threatening you twice the glucocorticoid levels in your bloodstream next variable the guy is threatening you in your face what do you do next do you abdicate control and let him start the inevitable fight or do you at least get some control in this circumstance and be the one to start it two different ways of measuring this but showing males who abdicate control much higher levels of glucocorticoids next variable you've had the fight with the guy can you tell whether you won or lost oh this is rather fundamental and pathetically again your average male baboon has the same likelihood of what behavior he does afterward depending on regardless of whether he's won or lost if you can't tell the difference between a promotion and losing you're going to have significantly higher glucocorticoid levels finally you've had the fight and you've lost what do you do next you go and mope by yourself or do you go and beat up on somebody smaller okay how best to frame this male baboons who lack social outlets and go and mope by themselves significantly higher glucocorticoid levels look at this can you tell the difference between big things and little things if it's a big thing do you at least get some control can you tell if the outcomes good or bad and if it's bad you have some effective coping outlets people paid to be taught to do this sort of thing and you go back in the records of these guys these low cortisol guys and you look at them back when they were juveniles and they were like this back when it's a long-term stable trait final marker independent of rank stability of rank male male competitive style etc the single best predictor of having elevated stress hormone levels is being socially isolated how often do you groom how often you sit in contact with someone else how often do you hold an infant all of this being highly predictive okay so what do we got here first third of the talk extremely depressing we are now 60 70 years having to think about stress as playing adverse roles and how all sorts of outposts in our body function almost certainly we need to think about stress playing an adverse role in the consequences of some of the most common of neurological disasters and how we age and how some of us will age cognitively more successfully than others and increasing reasons to think this is quite pertinent our owl to our own brains amid all that bad news one version of the good news is showing you at the more reductive and the capacity to understand the nuts and bolts of what goes wrong to begin to design rational interventions gene therapy and as we all know that's just the tip of the iceberg of some things that could hopefully be done down the line there is hope in that realm final third here at this more integrative level when looking at the sort of stressors that do us in these are not the ones where everyone will catastrophic ly have a stress response this is the world of us having these individual differences that are supremely sensitive to our psychological makeups and our social contexts and basically that's the place to stop here this in so far as we are not getting ulcers because we are chased by predators or having to wrestle people for canned food items and bombed out supermarkets insofar as we live well enough and long enough to pay for these things insofar as we are smart enough to invent this stuff and foolish enough to fall for it all of us have the potential I think to be wise enough to keep it in perspective so on that note let me acknowledge the members of my lab we've done this work and my field collaborators over the years out in Kenya including my wife and thank you for your attention thanks Robert that was just superb given the hour I think perhaps we'll adjourn to the South lobby for the reception so if you have questions for Robert he will be there to address them so please do come to the reception thank you all very much to be a monic

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Length: 70min 29sec (4229 seconds)

Published: Fri Feb 18 2011