https://www.economist.com/technology-quarterly/2023/09/25/eating-fewer-calories-can-ward-off-ageing
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Take the mtorc1 pathway. The complex of proteins which gives it its name first came to attention because an immune suppressant called rapamycin has a strong effect on it: hence “mechanistic target of rapamycin complex 1”. That gives no real clue, however, to the fact that the signalling pathway in which mtorc1 sits is a complex set of controls and feedbacks designed to regulate metabolism in response both to the availability of nutrients …
The ambit of this regulatory power is broad; it influences the rate at which cells break down damaged internal structures (“autophagy”), the balance of their protein content (“proteostasis”) and the reproduction of their mitochondria, components responsible for turning the calories it receives into a form of energy its proteins can use. Autophagy, proteostasis and mitochondrial reproduction are three more of the 12 hallmarks of aging.
What is more, rapamycin, the effects of which give mtorc1 its name, turns out to lengthen the lives of lab animals even though it curbs their immune responses. …There is thus a search for “rapalogs” which provide the benefits of a tuned-up mtorc1 pathway without so many costs.
Another pathway which calorie-restriction studies have marked out as promising is named after a protein called ampk (don’t ask). This regulates the production of ATP, a small energy-carrying molecule produced in mitochondria. When atp levels fall, the ampk pathway increases a cell’s sensitivity to insulin.
Metformin, a drug used to treat type-2 diabetes, does so by activating the ampk pathway. Like rapamycin, it extends the lifespans of healthy mice.
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