Venki Ramakrishnan

And so this idea that you destroy that ability to divide forever in most of our cells and restrict it to just a few cells, like our stem cells, that's probably evolved as a cancer prevention mechanism. And that, again, is because you don't want to get cancer before you have a chance to reproduce.

And so this idea that you destroy that ability to divide forever in most of our cells and restrict it to just a few cells, like our stem cells, that's probably evolved as a cancer prevention mechanism. And that, again, is because you don't want to get cancer before you have a chance to reproduce.

And once you've reproduced, okay, the consequences that you age, that's okay because you've passed on your genes. That's the evolutionary game.

And once you've reproduced, okay, the consequences that you age, that's okay because you've passed on your genes. That's the evolutionary game.

No, there are many different aspects to aging, and they happen from the molecular level all the way to the level of tissues where cells talk to each other. So just to give you an example, we could start with DNA. which encodes proteins and so on. And DNA damage is one of the primary causes of aging. And of course, we have extensive repair mechanisms, but the DNA repair mechanisms themselves

No, there are many different aspects to aging, and they happen from the molecular level all the way to the level of tissues where cells talk to each other. So just to give you an example, we could start with DNA. which encodes proteins and so on. And DNA damage is one of the primary causes of aging. And of course, we have extensive repair mechanisms, but the DNA repair mechanisms themselves

can break down with aging. So it's a kind of auto catalytic or accelerating phenomenon that DNA damage becomes increasing with age. But that's a cause of aging. And then the proteins that are made using genetic information They often, the quality of those proteins goes down with age. Our ability to recycle proteins that are defective also goes down with age.

can break down with aging. So it's a kind of auto catalytic or accelerating phenomenon that DNA damage becomes increasing with age. But that's a cause of aging. And then the proteins that are made using genetic information They often, the quality of those proteins goes down with age. Our ability to recycle proteins that are defective also goes down with age.

So there's all those levels at what I call the protein level. And then this also affects organelles like our mitochondria, which are our organelles in our cell that are responsible for energy production. Of course, some of you may be interested that mitochondria actually were bacteria that were swallowed up by an ancestral cell of ours.

So there's all those levels at what I call the protein level. And then this also affects organelles like our mitochondria, which are our organelles in our cell that are responsible for energy production. Of course, some of you may be interested that mitochondria actually were bacteria that were swallowed up by an ancestral cell of ours.

And the two somehow managed to live in a symbiotic state ever since. But mitochondria now control a lot of the health of the cell, including a lot of metabolic pathways. And so if mitochondria become dysfunctional, that's another cause of aging. or the lysosome, another organelle which is responsible for removing the junk in our body.

And the two somehow managed to live in a symbiotic state ever since. But mitochondria now control a lot of the health of the cell, including a lot of metabolic pathways. And so if mitochondria become dysfunctional, that's another cause of aging. or the lysosome, another organelle which is responsible for removing the junk in our body.

So all of these proteins that accumulate that are defective or entire organelles that are defective are taken to the lysosome and recycled, basically degraded and recycled. But that process called autophagy can also decline with age. And then cells themselves can decline. So I pointed out that when cells are stressed, when they sense damage, they go into a state called senescence.

So all of these proteins that accumulate that are defective or entire organelles that are defective are taken to the lysosome and recycled, basically degraded and recycled. But that process called autophagy can also decline with age. And then cells themselves can decline. So I pointed out that when cells are stressed, when they sense damage, they go into a state called senescence.

These cells can't divide, but they, in turn, they secrete inflammatory molecules. And early on in life, that has a purpose because this senescent cell is saying to the immune system and other repair cells that, look, I'm damaged. This site around me is probably damaged. Maybe there's a virus attack. And so come here and repair the damage.

These cells can't divide, but they, in turn, they secrete inflammatory molecules. And early on in life, that has a purpose because this senescent cell is saying to the immune system and other repair cells that, look, I'm damaged. This site around me is probably damaged. Maybe there's a virus attack. And so come here and repair the damage.

And so in the process, they repair the damage and the senescent cell is destroyed. But as we get older, the ability to destroy the senescent cells has also declined. And of course, more and more senescent cells are formed because other processes stop working and more cells go into senescence. So you get this buildup of senescent cells and inflammation. So that's another problem.

And so in the process, they repair the damage and the senescent cell is destroyed. But as we get older, the ability to destroy the senescent cells has also declined. And of course, more and more senescent cells are formed because other processes stop working and more cells go into senescence. So you get this buildup of senescent cells and inflammation. So that's another problem.

And then stem cells, which are the cells which are responsible for regenerating tissues. So they have to do two things. They have to regenerate themselves, and they also have to regenerate the tissue that they are sort of in charge of. Early stem cells can make any kind of tissue. So in an early embryo, you have what are called pluripotent stem cells. These cells can make anything.

And then stem cells, which are the cells which are responsible for regenerating tissues. So they have to do two things. They have to regenerate themselves, and they also have to regenerate the tissue that they are sort of in charge of. Early stem cells can make any kind of tissue. So in an early embryo, you have what are called pluripotent stem cells. These cells can make anything.