Venki Ramakrishnan

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.

But later stem cells, later in development, they specialize. So some stem cells can only make skin and hair. Others can only make cells of the nervous system. Of course, there are many different types, but still a subset. Others can only make cells of the blood, and that includes the entire immune system and our red blood cells. So these stem cells themselves

But later stem cells, later in development, they specialize. So some stem cells can only make skin and hair. Others can only make cells of the nervous system. Of course, there are many different types, but still a subset. Others can only make cells of the blood, and that includes the entire immune system and our red blood cells. So these stem cells themselves

decline with age because many of them go into senescence. And so you get a depletion of stem cells. And the quality of the remaining stem cells is also not as diverse and not as good because they're often descended from a few clones which don't have necessarily the optimal properties. So that's another cause of aging. And that leads to tissue loss.

decline with age because many of them go into senescence. And so you get a depletion of stem cells. And the quality of the remaining stem cells is also not as diverse and not as good because they're often descended from a few clones which don't have necessarily the optimal properties. So that's another cause of aging. And that leads to tissue loss.

For example, a common problem with aging is loss of muscle and frailty. So you can see that at every level there's an effect, but each level is not independent. They all interact with each other. And so there's this complicated web of things happening at different levels of complexity.

For example, a common problem with aging is loss of muscle and frailty. So you can see that at every level there's an effect, but each level is not independent. They all interact with each other. And so there's this complicated web of things happening at different levels of complexity.

Yeah, it does. People have made a lot of progress. For example, I mentioned senescent cells. So amazingly, people have been able to target senescent cells using some particular biomarkers, things characteristic of senescent cells. And when they destroy senescent cells in, say, mice, aging mice, the symptoms of aging improve in those mice. And so that's one way.

Yeah, it does. People have made a lot of progress. For example, I mentioned senescent cells. So amazingly, people have been able to target senescent cells using some particular biomarkers, things characteristic of senescent cells. And when they destroy senescent cells in, say, mice, aging mice, the symptoms of aging improve in those mice. And so that's one way.

that one of the more exciting and more challenging ways to deal with aging is to reprogram cells. So you take cells and you reprogram them so they go slightly backwards in development. So effectively they become like stem cells. So you're reactivating stem cells for different types of tissues.

that one of the more exciting and more challenging ways to deal with aging is to reprogram cells. So you take cells and you reprogram them so they go slightly backwards in development. So effectively they become like stem cells. So you're reactivating stem cells for different types of tissues.