Science Vs - How Bats Break Science

Episode Date: July 20, 2023

Many bats can live a bizarrely long time, and brush off viruses that kill people. How do they do it and what can we learn from them? Zoology Professor Emma Teeling and bat researcher and clinician Matae Ahn fly through the science.  Find our transcript here: https://bit.ly/ScienceVsBats  This episode was produced by Flora Lichtman with help from Wendy Zukerman, Joel Werner, R.E. Natowicz, and Michelle Dang, Rose Rimler. Editing by Jorge Just, Annette Heist and Blythe Terrell. Fact checking by Carmen Drahl. Mix and sound design by Bumi Hidaka. Music written by Billy Libby, Emma Munger, Darah Hirsch, So Wylie and Bobby Lord. Thanks to everyone we reached out to for this episode including Dr. Vera Gorbunova, Dr. Sharon Swartz, Dr. Gerry Wilkinson, and Dr. Lisa Cooper.  Learn more about your ad choices. Visit podcastchoices.com/adchoices

Wendy, I have a story for you, and it is absolutely batshit, and you are guana-wana-hear-it. Oh! I have no idea what you're guana-tell-me. A lot is about to happen. Here with me is award-winning science journalist and host of Every Little Thing, Flora Lichtman. Hello, Flora. Hello. While the team at Science Versus is diving into topics for next season, Flora was like,

Wendy, turn on your microphone. I got to tell you something about bats. This can't wait one more minute, Wendy. I'm here, ready to go. Right off the bat, I want to introduce you to Emma Teeling, bat biologist and full professor of zoology at University College Dublin, because she does not fly away from a bold statement on bats. They are by far the most magnificent of all mammals that have the rarest of all traits. Emma is going for it. The most magnificent. I mean, I did feel I'm very competitive, so I was like, whoa.

Does she know me? Anyway, bats, bring it on. Let's just count the ways. Bats turn teenage human heartthrobs into teenage vampire heartthrobs. They give Sarah Michelle Gellar seven seasons of work and no more. I'm a vampire slayer. They also created the best Sesame Street character. I am the count because I love to count. I really love to count. Betty, Betty, Betty, Betty,

Betty, Betty, Betty, Betty, Betty. But beyond their IMDb cred, bats are the only mammals to fly. Plus, they echolocate. They find their way around in the dark by making sound and listening to how it echoes. That's crazy. But there are two special bat tributes I want to home in on today. First of all, they live for a weirdly, mysteriously long time. The longest-lived bats can live for decades. Interesting. And number two is about their immune system. Many viruses that kill us, from the flu to Ebola, bats brush them off like a fly. Huh. So bats scat all over aging, and they fly in the face of immunology.

And I am going to hang upside down from a spindly limb and say, bats break science. Whoa, that's a very big call, Flora. How do they live so long and crush killer viruses? And what can we learn from them? Wouldn't you like to be youthful until you die? That's what we're clawing into today. I'm in. I'm holding on stalactitely to your every word. Oh, sorry. You've got such a bad influence on me, Flora. Do not blame me, Wendy. That's ridiculous. It's season three of The Joy of Why, and I still have a lot of questions. Like, what is this thing we call time? Why does altruism exist?

And where is Jan Eleven? I'm here, astrophysicist and co-host, ready for anything. That's right. I'm bringing in the A-team. So brace yourselves. Get ready to learn. I'm Jan Eleven. I'm Steve Strogatz.

And this is... Quantum Magazine's podcast, The Joy of Why. New episodes drop every other Thursday, starting February 1st. What does the AI revolution mean for jobs, for getting things done? Who are the people creating this technology, and what do they think? I'm Rana El-Khelyoubi, an AI scientist, entrepreneur, investor, and now host of the new podcast, Pioneers of AI. Think of it as your guide for all things AI, with the most human issues at the center. Join me every Wednesday for Pioneers of AI. And don't forget to subscribe

wherever you tune in. Welcome back. Today, we are uncovering the mysteries of the bat with Flora Lichtman. Now you're going to tell us why bats live forever. Yes, and Vendy, this is the first thing you need to know. Lifespan for most mammals follows a general pattern. You're born, you suffer, and then you die, probably alone. Oh, come now.

There's some podcasts in the middle there. And generally for mammals, the bigger you are, the longer you live. And the smaller you are, the shorter you live. Here's bat biologist Emma Teeling again. Small things, they live very fast and they die young. Think of a mouse, think of a shrimp. So the thing is that bats are unusual because they buck this trend. Humans buck the trend too. Shout out to soap and medicine. But if we lived proportionally as long as the longest lived bat, corrected for body size, we'd be living for centuries. We'd be like 250 years old. They blow us out of the cave on lifespan. And that is with all of our medical intervention. Wow. That is so impressive

that they bat us out of the water with no vaccines, no hand washing. No hand washing. I really love the image of them at their tiny little sink, sudsing their little claws. And it's not just that they live a long time. Researchers don't find many visible signs of aging. For example, gray hair. You don't see that in the bats that we're looking at. They seem to be able to reproduce into old age. And here's the kicker. They don't show signs of age-related disease.

You don't seem to see evidence of cancer. You don't see evidence of big tumors on these bats. They're living way longer than expected. You don't see this. So it's not just that they're holding on by a thread into old age. They are literally like vampires. I think they're more like Paul Rudd. They age so slowly you can barely detect it. So under the hood biologically, what is happening here? That is what Emma is batting her head against the wall to find out. That is a question I wanted to know. How do bats resist aging? To find out, for over a decade, Emma has

been studying these wild, long-lived bats in Brittany, France, along with a colony of scientists, which included Nicole Foley. I did my PhD with Emma, who I think you've been talking to previously. Nicole's now a research scientist at Texas A&M, and she was the lead author on the study we're going to talk about. So Nicole was out studying these bats, but the field sites are maybe not exactly what you'd picture. These bats are not living in caves. There's some that are in churches, some that are in the roofs of schools. These scientists work with a French naturalist association

that helps them track down these long-lived bat populations and arrange access, including to these old churches. And I just want Nicole to paint you a picture. The churches are amazing. Like, I mean, think of the most kind of Dracula Gothic church with, like, you know, the really, like, narrow steeples and it's, like, super high and imposing. Yeah, I mean, just picture what if Disney had to do a church for a villain. So the bats wiggle their way in under the shingles of the roof and hang in the attic. Uh-huh. How do they catch them? This is another fun detail. Compared to other bat field work,

in this project, catching them is kind of a cinch. Normally you go out and you put up nets and you stay out all night in the forest and you catch bats that way and it's hard. Really, really hard work. Because we knew that the bats were in the attic and we knew where they were coming out, we just had to make like a little contraption. It's called like a harp trap because it just has like all of these like straight strings hanging down from it. They put this harp trap over the bat exit and then the bats fly out. They bump into the strings. And then we just kind of had like a plastic tube weaving its way down into like just a box on the bottom and you get a box of bats. It's like a laundry chute of bats. I mean, I kind of feel bad for the bats, right? Because they're like hanging out in the attic and they're like, time to party for the night.

And instead they're like, whoa, now I'm in a box. So these scientists have been catching these bats for years and they track them over their lives. So here's Emma again. Every single bat that's born in this colony, we catch them year after year after year, the same individuals. We take a little bit of individuals. We take a little bit of wing. We take a little bit of blood, a few drops. And then they analyze this tissue and blood to try to figure out why bats live so long. We release them and we look at markers of age. And one of the markers Emma has looked at are telomeres. These are the little caps at the end

of our chromosomes that protect your DNA from degrading, which is important because generally speaking, DNA damage can lead to cancer and other problems. And so what's going on with bats' telomeres? Okay, so generally in mammals, you may recall that telomeres get shorter as you get older. Right. And this science is changing all the time, but this shortening is considered one of the classic hallmarks of aging. That's why Emma was looking at it. So we asked this question, do telomeres shorten as we would be expected in these long-lived bats or not? And we looked at young, middle-aged, and older bats. So they asked, do older bats have shorter telomeres

than younger bats? And what we found was extraordinary. In the longest-lived bats, their telomeres did not shorten with age. Oh, wow. So in the older bats, their telomeres, on average, weren't shorter. Yeah. So this was a big result. Like, it was so surprising that Nicole, Emma's student at the time, couldn't believe it. This was her response. Like, it's just, it's wrong. What did I do? I feel like that's a natural tendency. It's like, oh, that's interesting.

It must be nonsense. Then you go back and you do your living best to find all of the things that you may have done wrong. And eventually you kind of get to the point where you run out of ways of confirming that you're wrong. So you must be right. Wait, why was she so unconvinced

and then convinced? Is that because this is so confounding that these bats don't have this telomere shortening thing? They're not following the rules. Here's Emma again. So what this meant was that potentially bats had a way of maintaining telomerenus, which is a good thing, but how do they do it? And Emma's working on it. She has a couple weeds, some genes that might be responsible.

Right. So I'd tell them is the reason why bats have this longevity superpower. Well, as we know from the Marvel Universe, unraveling a superpower takes like 19 Robert Downey Jr. movies to really unpack. So telomeres are thought to be part of it, but the full story is complicated. But next up, how bats bat away viruses that make humans shudder in fear,

which also has a starring role in the bat longevity story. Coming up, up to the break. Welcome to the Batcave. I'm here with special guest Flora Lichtman. We are swooping into the science of bats. Next up, why bats look at viruses the same way that Buffy looks at vampires. Is that what we're doing?

Couldn't have put it better myself. So yeah, one of the things that bats are known for is their ability to fight off viruses. And I've got an expert to fly through the science with us. Mate An is a bat biologist and human clinician from Duke and U.S. Medical School in Singapore. Yeah, bats, what they are most famous for actually, or sometimes infamous, is carrying many, many nasty viruses. Yes. I feel like from the pandemic, this is one fact a lot of people picked up about bats, right? Because there's a lot of coronaviruses in bats. Yes, SARS, MERS, and other kinds of viruses too, like Ebola. Bats carry viruses that cause deadly epidemics in humans. They get infected, they don't show symptoms, they don't get sick, and then they clear the virus.

I'm so jealous as someone who's had a lot of viruses this year. Now, anecdotally, they don't seem to show the same invincibility when it comes to bacteria and fungi. You might remember white nose syndrome, the fungal disease that's killed millions of bats across North America. Right. Yes. Yes, yes, yes. So not fully invincible, but seemingly invincible to viruses. Yes, most viruses. So how do they do that? They do it by keeping their immune system in a Goldilocks zone. So for mammals, there's a sweet spot when it comes to an immune response.

You want your immune system to attack and clear the virus, but you don't want it to fly out of control. Too much immune response can damage healthy cells, and you can die from that. In COVID, the immune response, inflammation, is often what kills people. Right. So, bad immune systems don't fly off the handle when a virus invades. How do they do that? Like, what is the...

What's the break in their immune system that stops it going haywire for viruses? Great question. And I'm happy to tell you that we are alive at the exact right moment in history to get an answer. Mate and colleagues just published a big paper on this. They looked at inflammasomes. These are like first responders in the immune system. Okay. Bats have them. We have them. Have you heard of them? No, no. It sounds like another pun, but it's real, this one. It's real. And you're not alone. Even among clinicians, most people don't know. I never learned it in my medical school. I never learned it in my PhD as well. So that's how new it is. This is the bleeding edge of immune research. What is an inflammasome? So in your body, there are proteins called inflammasome sensors that float around and detect danger, like viruses, bacteria, cell damage. And when they sense a problem, they, along with some other proteins, come together to form an inflammasome.

Now, that inflammasome then can deal with the problem directly. It can also recruit other members of the immune system to help out. Oh, and this is different from antibodies and other more well-known stuff in our immune system. Like this is a new thing in the immune system that we're still working out. It's another player, and it's a major player. Inflammasomes play a very important role in aging, including age-related diseases. Like Alzheimer's, Parkinson's, diabetes, heart disease, and they're key responders to viruses. Now, because bats don't show signs of age-related disease, and they fight off viruses so effectively, Matei and his colleagues

wondered if their inflammasomes were different somehow. Are they different somehow? Well, through a ton of molecular detective work, they found that bats make a protein that suppresses their inflammasomes. Ah, and that's what's keeping their immune system in this Goldilocks zone. That was the hypothesis. So to test it, Maté and his colleagues genetically modified mice so they made this same inflammasome-suppressing protein, just like the ones that bats make. And then they exposed these mice to inflammation-inducing crap of different varieties,

like the flu and chemicals that cause irritation. And so what did they find? So it was really cool. They found that these modified mice reacted more like bats. They didn't have as much inflammation in response to these irritants, and they were way less likely to die from the flu. Wow. Wow. So can I get genetically modified? Like, can they give me that protein? I want that protein. Mate wants you to have it too. They're working on this exact thing, a human drug version. Amazing. It's amazing that bats just have collected these tools? Like, why bats? Why are bats so good at all this? Yes, that is such a fascinating question. And it's a batter of debate. So one theory I heard

is that it comes down to their communal lifestyle. Some bats live in colonies of millions. They are packed into these caves, wing to jowl, which is just perfect conditions for virus transmission. So to cope with this germ storm, their immune system adapted, which might help them live longer. That's super interesting. It's just making me think that humans, because we also live in these incredibly dense cities now, but we haven't evolved that way, right? This is a very new modern phenomena to be so densely packed in our little caves. Yes, exactly. We live kind of like bats, maybe not quite as densely, but we don't have the immune system of bats. But here's another theory about how bats got this fairytale immune system and longevity.

And this one I heard from both Mate and Emma. It's the theory I am buying the most right now. It comes down to flight. Okay. So flying is hard on a bat. A bat's heart rate can go up to 1,000 beats per minute. Think of them like tiny, furry, flying race cars. They are operating at the extremes. They're stressing their machinery, guzzling fuel, and spewing out

chemicals. And all that can lead to DNA damage, inflammation, and other problems. So the idea would be that to evolve flight, bats have had to evolve a countermeasure to deal with this. The countermeasures are what protects them from the damage of living and allows them to have longer health span. And so they needed these adaptations or they would have just died. Like if you're going to have flight as a mammal, you better darn well have a proper immune system to handle that or you are crashing and burning. Crashing and burning. Yeah.

Is this how Superman can survive? He's actually a bat. I think that's Batman. I think it's the other one. But Batman can't actually fly. He's just a rich guy. He's just a rich guy. Everyone forgets that. He has no superpowers other than money. Yeah, you're right. So anyway, people pack holes in this flight theory because birds don't have all these adaptations. And both Emma and Mate

said, it's hard to prove this because it's an evolutionary theory. But they're like, either way, the thing that we're really excited about is how this works. What are the mechanisms that allow bats to beat viruses and to live these long, long, healthy lives? Wouldn't you like to be youthful until you die? Not have the ravages of aging. Methuselah. Methuselah lived till he was 916 and then just died. So it's living healthier longer, that's what we want to do. Finding ways to be able to, I suppose, tolerate the damage of living

for a much longer time without it making us sick. Our dream is to really learn from bats to benefit humans, to treat diseases. So that's the exciting part of bat research, I feel. It's really cool because I feel like we tend to just hear about certain animals in these very particular lights. The bats harbor viruses. But they have their own bat lives.

That ultimately can help us to create, to live our own human lives. It's ultimately about us, though. Let's be real. Thanks so much, Flora. Thanks, Wendy. Thanks for having me. That's Science Versus. And before you go, don't go anywhere because Flora made this amazing video about bats flying. It's just a couple of minutes.

It's beautiful. Go find it on our Instagram, which is science underscore VS, or you can find it on my TikTok, which is at Wendy Zuckerman. And if you are listening on Spotify, you can just see it right there on Spotify. Thanks so much, Flora, for making it. Oh, it's gorgeous. Today's episode had more than 70 citations in it. And if you want to see them and learn more about bats, then go to our show notes and click on the link to the transcript. We are racing down facts and funnies for next season, which is going to kick off in September. But in the meantime, in just a couple of weeks, we're going to have the winners for you for our inaugural favorite science versus episode

competition, which we're calling Physic favorite science versus episode competition. We are going to work on a title as well. First up is the winner of the drug category, your favourite episode that we've done about drugs, and we've done quite a lot, Adderall, Molly, Mushies. It was a hotly contested category. This episode was produced by Flora Lichtman, with help from me, Wendy Zuckerman, Joel Werner, Ari Natavich, Michelle Dang

and Rose Rimler. Editing by Jorge Just, Annette Heist and Blythe Terrell. Fact-checking by Carmen Drahl. Mix and sound design by Bumi Hidaka. Music written by Billy Libby, Emma Munger, Dara Hirsch, So Wiley and Bobby Lord. Thanks to everyone we reached out to for this episode, including Dr Vera Gorbunova, Dr Sharon Swartz,

Dr Gerry Wilkinsonunova, Dr. Sharon Swartz, Dr. Jerry Wilkinson, and Dr. Lisa Cooper. And a little fact check, a little Bible study for my listeners. Methuselah lived to 969 years old, not 960 years old. Science Versus is a Spotify Studios original, and if you're listening on Spotify, you should tap the bell. There's a little bell icon and if you tap that, then you'll get new notifications every time an episode comes out. I'm Wendy Zuckerman. Back to you next time.