It was through the study of a mutant worm that led to the breakthrough discovery of aging, which seemed to be controlled by metabolic processes.

The more researchers studied these processes, however, all signs pointed to the nucleolus, writes the New York Times. “We think the nucleolus plays an important role in regulating the lifespan of animals,” said Adam Antebi, a cellular biologist at the Max Planck Institute for Biology of Ageing in Germany. 

Just to remind you, the nucleolus is the cell’s ribosome factory. They are like micro-machines that make proteins that cells then use for purposes of building walls, forming hairs, making memories, communicating and starting, stopping and slowing down reactions that help a cell stay functioning. During this process, it uses about 80% of a cell’s energy. However, there is a lot more to the nucleolus than just making ribosomes. 

Dr. Antebi suggests that as the nucleolus gets smaller, it also starts remodeling the things it would create to make the best available supplies. This is a highly coordinated process though, with lifespan being thought of as how well the nucleolus balances the need to grow with the need to repair, correct mistakes and make sure everything works. 

A drug called rapamycin, that blocks the signals of one metabolic pathway, extends life in different species from yeast, worms and fruit flies to mice. Researchers discovered that modest dietary restriction and exercise shrank nucleoli in muscle cells of some people over age 60. People who suffer from diseases like cancer or progeria, a type of accelerated ageing, tend to have enlarged nucleoli. 

These kinds of effects can be seen in many different species. “It’s amazing – even if genetically identical, some live a short life and some live a long life,” he added. “We think that the smaller nucleoli may be a cellular hallmark of longevity,” in certain cells under certain conditions, he noted. 

Despite this, more research is needed to see if the size of these structures is simply just markers for longevity or ageing, or if they actually cause it. “We’ve spent lots of money on trying to find biomarkers of longevity or ageing, and maybe it’s just sitting under the microscope for us to see,” concluded Dr. Antebi. 

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