Short Wave - The Biologist Who Talks With Cells

Episode Date: December 8, 2022

The human body is made up of more than 30 trillion cells, but how do they all work together? It's all about communication! "They talk through molecules going from one cell to the adjacent cell," says Dr. Sandra Murray, a professor of cell biology and physiology at the University of Pittsburgh who studies how cells communicate with each other to do complex tasks, like close a wound or deliver a baby. This year, Dr. Murray became the first person of color elected as president of the American Society for Cell Biology. She talks with host Aaron Scott about the beautiful language of cells, how she made her way as a Black woman in STEM, and what gives her hope in her field today.See pcm.adswizz.com for information about our collection and use of personal data for sponsorship and to manage your podcast sponsorship preferences.NPR Privacy Policy

You're listening to Shortwave from NPR. Scientists estimate that there are more than 30 trillion cells in the human body. That is more than 30 trillion microscopic sacks of cytoplasm and proteins all collaborating together to do the really complicated things necessary to keep us alive. Which raises a big question. How do these tiny cells, none of which have their own brains, how do they all work? together. I'm a cell biologist who looks at how cells communicate with one another, how they talk to each other, and they talk through molecules going from one cell to the adjacent cell. Dr. Sandra Murray is a professor of cell biology and physiology at the University of Pittsburgh,

and she spent a lifetime trying to understand the language of cells. Things that could communicate would be things like the blood vessels bring information to the cells and the cells on the outside get a molecule that says, let's do something. They get a hormone carried in the blood, and that blood gets only to the outside. And those cells say, oh, wow, there's something happening. I have to move, let's move, let's move.

Then the molecule is moving from cell to cell to cell. And then all of a sudden, all the cells becoming a team. And so there's an example where you would use a hormonal stimulation and get the entire population doing something together. Like, say, to deliver a baby? The smooth muscles of the uterus where the baby is developing, those cells need to do something to push the baby out. And you need maybe all of the cells to push at the same time.

So you can get a lot of communication. And that communication is saying, everybody on board, push. And then the baby's delivered. So the cells tell each other when to go and also when to stop. If you've ever cut yourself, you might wonder why the cells in the area of the wound resealed the wound and gave you a pretty nice looking skin repair. Why didn't they just keep going and fill the whole room? And in a cancer cell population, more or less that's sort of what happens,

rather than the cells controlling the number of cells that are the cells, They just keep dividing and result in the person who has the cancer, not being able to function properly because you have this massive growth of cells. But while understanding how cells communicate has huge implications for fields like medicine, Sanders stresses asking why for its own sake is really important too. I'm a basic scientist, which means that I don't always look at what my application is. I look at how do cells communicate because I observe that and I want to know that. It's a field she had to fight to enter. Earlier this year, she was the first person of color elected as president of the American Society for Cell Biology. But her path might have been very different.

Back in the 1960s, a school counselor told her she'd be better off in vocational training because she was black and a girl. She even asked me, have you seen a colored woman? As a scientist, and I was thinking, you know, I haven't seen a hippopotamus. I haven't seen a giraffe. They haven't taken me to a good zoo yet. I mean, I believe they existed. So they must exist. My world was small. So what if I had never seen one?

So today on the show, we talked to Sandra Murray about the beautiful language of cells, how she made her way being a black woman in science and what gives her hope today. I'm Aaron Scott, and you're listening to Shortwave, the Daily Science Podcast. podcast from NPR. So Sandra, to start out, would you tell us a little bit more about how our cells are able to talk to each other? So I look at the structure that allows that communication of molecules from one cell, and that's called a gap junction or a connection channel.

I look at those channels, and I look at how those channels are formed, how they're removed from the cell surface, and how they recycle. There are a lot of different probably signals that go through, and we haven't discovered all the signals they go through. So they're speaking in a language we may not understand because we don't know what the signal is, but we know that certain things about the language they can speak, meaning we know how large a molecule can go through this channel.

I've done a lot of research on looking at one molecule, which is called cyclic AMP. In order to study that, you put one kind of cell in the incubator with another kind of cell and you let it make a junction. And after it makes a junction, you stimulate only one of the cells and then you look in the other cell and say, what changes, if any? Can this adrenal cell talk to a cell from the ovary that normally wouldn't occur? But can I put it in culture and therefore stimulate the ovary cell within? hormone to say, can I make a cell from the ovary, make the adrenal cell, make cortisol. And then I know I'm communicating. So they're not yelling, but they're passing molecules. And this conversation is all

happening at the most microscopic of levels. Would you tell us a little bit about the tools that you use to track how these molecules are moving back and forth between cells? Yes. If we let one of the molecules glow by coupling it with a fluorescent molecule. We then can see fluorescent molecule in the first cell. And then we can say, ah, does it move to the other cell? And early on, that's how it was discovered, how large a molecule could move because they put larger and larger and larger molecules in and then said, does it come from cell to cell? So we use fluorescent molecules. We use live cell imaging, which means that we just follow in a living cell. We don't fix the cell.

The cell is alive, and we can look at where the molecule is going. When we want to get more resolution, we use super resolution microscopy, which allows us to look even closer at what's going on. And when we really want to see at the ultrustructure, when we really want to see what's going on, we go to electron microscopy. The way you describe it of the dyes going back and forth and even the time lapse, which is almost like stop motion animation, it sounds very, very beautiful.

What do you think about as you watch it? I mean, how does it feel to get to observe this process that's going on all the time in our bodies, but that most of us never get the chance to see? I think it gives me a rare and wonderful opportunity to see art in motion. It's science you can see. And the beauty of seeing some of these electron micrographs, of seeing some of these fluorescent microscopes with the colors going back and forth,

it is art. It is truly art. I love that. I mean, the next time I have a cut that's healing, I'm going to look at it as like all my little cells are putting on a little performance for me. If only I had slightly more magnification to watch it. Absolutely. How did you end up on this path? I'm curious what got you wanting to talk to cells, or at least to listen in on their conversations?

Very early on, I got into science, probably in elementary school, because I really, really liked talking about science. What does coal look like? My first project, or I was turning hard water, soft and soft water hard. Science fairs were very important. I mean, being able to participate and feel like I was doing science, it made me want to do more. And it made me want to ask questions, why, how I went and looked for it on my own. So that by the time I got to college and they said, you know, what do you want to major in? It was easier for me to do biology, which I liked.

As a high schooler, Sandra worked in a lab at the University of Illinois. And she tells this story about how she was tasked with cleaning off a bunch of slides, and she accidentally cleaned off the labels in the process. So to help her relabel the slides, somebody told her to match the pictures in a reference book with what she saw under the microscope. Microscope? That's what you use a microscope for? And so they took me to the microscope,

and then they said, here's a histology book, an Atlas. And see, if you want to know, you see these cells have to match. So that is when I discovered the microscope, the beauty of the microscope, the necessity of the microscope, and the microscope has been something that has been dear for me for a long time, therefore. And so you wanted to do biology in college, and yet I understand that they wanted to put you into kind of the secretarial track? Absolutely. And so the first year of high school, I was already in college prep. everything was going well, but someone had told me, in order to go into science, you really needed Latin. So I went to my consular in order to say, I need to get into this Latin because I'm going to become a scientist.

And the consular that was in another cubicle over from him stood up and said, I am so sick of you people coming in here with your high ideas. After all, you're colored and you're a girl. You will never be a scientist or a doctor. Here's what you can be. I'm going to help you. And she took my paperwork and she moved me from college prep to vocational training and told me at best, at best, I might be able to help scientists and doctors.

I would never be able to be one. And the best I could do is try to be very good as a secretary. It took a while for me to get back and to, college prep. I graduated top 10% of my class from high school, and I expected at any moment, someone was going to jump up and say, wait a minute, when did she get out of secretarial training? But no. When was that? Can I ask? That was around 19, just before 1963. What was it like then to go into undergraduate and graduate programs? Did you start to see women of color as scientists, or did you find that you were, in many cases, the first person?

I was pretty much the only person in my class. I went to University of Illinois. There was a Dr. Bond, who was black. He was not my biology teacher, but I knew he existed. I went to Texas Southern, and there I saw black instructors, and I saw black students. I saw minorities. of all kind. Then I went to Iowa, and it was not that that was not the case at Iowa. And it hasn't been the case pretty much after that. And I think I read that you were the first woman of color to become a full professor at your school now. That's certainly true, yes. And the first to be tenured. And that means that there's work to be done. I think there's a lot of hope. I asked my niece to do a journal cover for me.

I said, give me a scientist who is trying to control time, and it's not, they're just out of time. And I was rushed. I didn't say, give me this kind of scientist. I just said, give me a scientist. And she gave me a black woman running in a clock, and she gave me a woman with true curves. if I had asked this of myself when I was in high school and someone said, give me a picture of a scientist, I would have given them Einstein. My image of a scientist would have been a white male. We have a group of individuals now coming forward who see themselves as being scientists.

Not have you ever seen one, but you could be one. And so that gives me hope that the younger. generation somehow can see themselves in science, technology, engineering, and math. Dr. Sandra Murray, it has been an honor and a joy to talk to you. Thank you. Thank you for having me. Before we wrap up a huge thank you to our shortwave plus listeners, you like all the cells working together to keep our show moving. And if you're a regular listener who hasn't yet subscribed, consider it. We can't do what we do without your support.

and it means you get to listen without sponsor interruptions. Find out more at plus.mpr.org slash shortwave. This episode was produced by our senior supervising editor, Giselle Grayson and Margaret Serrino. It was also edited by Giselle. Britt Hansen checked the facts. The audio engineer was Neil Tewalt. Brendan Crump is our podcast coordinator. Beth Donovan is the senior director of programming,

and Anya Grunman is the senior vice president of programming. I'm Aaron Scott. Thanks as always for listening to Shortwave from NPR.