Now, Dillin and his team have expanded that finding by discovering new details about how mitochondria in the brain communicate with cells across the worm\u2019s body to extend life.<\/p>\n

First, he had to understand why damage to the brain\u2019s mitochondria could possibly have a beneficial effect on the organism. A mitochondrion\u2019s process for generating energy requires exceedingly complex molecular machinery with dozens of different protein parts. When things go awry, such as when some components are missing or misfolded, mitochondria activate a stress response, known as the unfolded protein response, which delivers repair enzymes to help the complexes assemble properly and restore mitochondrial function. In this way, the unfolded protein response keeps cells healthy.<\/p>\n

Dillin expected this process to unfold only inside the neurons with damaged mitochondria. Yet he observed that cells in other tissues of the worm\u2019s body also turned on repair responses even though their mitochondria were intact.<\/p>\n

It\u2019s this repair activity that helped the worms live longer. Like taking a car to a mechanic regularly, the unfolded protein response seemed to keep cells in good running order and function as anti-aging detailing. What remained mysterious was how this unfolded protein response was communicated to the rest of the organism.<\/p>\n

After some investigation, Dillin\u2019s team discovered that the mitochondria in stressed neurons were using vesicles \u2014 bubblelike containers that move materials around the cell or between cells \u2014 to carry a signal called Wnt beyond the nerve cells to other cells in the body. Biologists already knew that Wnt plays a role in setting up the body pattern during early embryonic development, during which it also triggers repair processes like the unfolded protein response. Still, how could Wnt signaling, when turned on in an adult, avoid activating the embryonic program?<\/p>\n