Mitch Leslie in Science:
The tails were a clue. As some kinds of mice get old, their tails can stiffen and kink. But the aged rodents in the lab of molecular biologist Shin-Ichiro Imai at the Washington University School of Medicine in St. Louis sported tails that were limber and nearly straight. The genetically altered mice seemed to defy aging in other ways, too. They were more robust than control mice and spent more time scampering in their exercise wheels. Most dramatic, the animals lived about 7% longer than their normal counterparts, gaining an extra 58 days of life, Imai and colleagues reported earlier this year in Cell Metabolism.
The genetic modification the researchers had made boosted a key communication signal from the animals’ brain to their body. Thanks to the tweak, a specific group of neurons in the hypothalamus, a physiological control center deep in the brain, remained active as the animals got older. Imai’s team discovered that those neurons send signals to the animal’s fat stores via the sympathetic nervous system, a network of nerves carrying messages from the brain throughout the body. In response to the signal, the mouse fat burns lipids and secretes a long-distance signal known as NAMPT that forestalls aging-related damage in other parts of the body, including the hypothalamus itself.
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