The Science of Cell Death

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Show Me the Science with Luke O'Neill 14 min 1 speaker 8 chapters transcribed 1 month ago

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What is cell death and why does it matter for health?

Unknown 0:00

Що мідесанс? With Professor Luke O'Neill. News Talk Original Podcast.

Luke O'Neill 0:08

Hello, Luke One here, and welcome to Show Me the Science, my weekly podcast. Now, as I've mentioned, I'm happy to take requests to L A O'Neill, to L's at tccd.ie. And this one is a request from Jared McNamara. And Jared's asked me to do the science of cell death. And Jared, I think you work on this yourself. Um and it's a fascinating topic, I must say. And again, I've been watching this for decades as an area of immunology. Uh it's very important how cells die. They die because they're infected. They sometimes die because they're destroying your own tissues and there's a way to take them out. So it's a very important aspect um of immunology is the area of cell death, and I'm very glad that Gerald has recommended it.

Luke O'Neill 0:48

Uh now and if you do a subject like biochemistry or molecular medicine, you will do loads of lectures on this topic of how important it is, as I will explain. Now obviously cells die. Your body is made up. Up of cells, and they get old and they die. And this has been on for a long time, obviously, otherwise you'd be immortal. Of course, cancer cells strangely don't die. And that's an aspect of which I will come on to the relevance of this, because some of those cancer cells escape death. So cell death as an area is also very important in the field of cancer research. And y if you go back about fifty years, uh or even forty years, when I first began as a biochemist, this wasn't studied at all. The view was cells died.

Luke O'Neill 1:23

Die, hard luck, and that's the end of that, and they get replaced. And it was also known that certain things kill cells. So poisons, for instance, um will kill a cell, clearly. You know, if you put a cell in acid in a lab, it'll die, you know, and this is felt to be sort of a consequence of just sort of nonspecific injury, if you like, and nobody really thought it was that interesting. And it was quite a kind of niche area to study, but then it begins to take off. And the reason why I take off.

How did the concept of programmed cell death (apoptosis) originate?

Luke O'Neill 1:48

Takes off is some scientists begin to realize that there's something specific going on in certain situations when cells die. And one area is development. So when a when a fetus or a new organism is developing, very often tissues will grow and then they'll recede a bit and grow again, and that's because the cells are dying. But they're dying in a very ordered way. Because the problem is if a cell explodes, kind of non-specifically explodes, that can be dangerous. Damaging to a tissue because it's releasing all its contents and that's noxious, right? So if you want to control cell death in a way, uh you will have to make sure that doesn't happen. A great example in us humans is, and I bet you don't know this, that when we're developing in the womb, we've webs.

Luke O'Neill 2:28

Our ancestors remember were amphibious creatures, and uh phylogeny recapitulates, ontogeny is the great phrase. But the the webs die right between our fingers and they get Eaten away. And that's control cell death in that web structure between your fingers. Those cells die off. And you sculpt tissues through cell death. And it was noticed this is a very controlled type of cell death, right? And that became sort of an area of research then. And that there was a term even coined for it. It was called apoptosis. Now there's a funny word, A-P-O-P-T-O-S-I-S. Apotosis, that means leaves falling off trees. Wiley came up with that name. And it looked like as if leaves were falling as the cells were dying. The cells themselves were detaching from the tissue and then kind of disappearing, a bit like leaves falling off a tree.

Luke O'Neill 3:13

That's where the name apoptosis came from. And that gets studied more and more and more. And finally, they figure out a very specific series of events inside the cell is happening when it undergoes this type of cell death. It's called programmed cell death. Another name for it. Apoptosis is also called programmed cells. It's undergoing kind of a program.

Why are caspases essential for controlled cellular demolition?

Luke O'Neill 3:33

And then very importantly, and this is where it gets kind of even more fascinating, and this programmed cell death process involves special enzymes inside the cell called caspases, and they get triggered, and these caspases chop things up.