On November 8, UCLA biologists reported that they had slowed the aging process in fruit flies. They activated a gene called PGC-1, which increases the activity of mitochondria, the tiny power generators in cells that control cell growth and tell cells when to live and die. “We took this gene and boosted its activity in different cells and tissues of the fly and asked whether this impacts the aging process,” said David Walker, an assistant professor of integrative biology and physiology at UCLA and a senior author of the study. “We discovered that when we boost PGC-1 within the fly's digestive tract, the fly lives significantly longer. We also studied neurons, muscle and other tissue types and did not find life extension; this is telling us there is something important about the digestive tract.”
The research appears in the current online edition of the journal Cell Metabolism, and will be published in an upcoming print edition. “By activating this one gene in this one tissue—the intestine—the fly lives longer; we slow aging of the intestine, and that has a positive effect on the whole animal,” said Dr. Walker, adding, “Our study shows that increasing PGC-1 gene activity in the intestine can slow aging, both at the cellular level and at the level of the whole animal.”
The biologists delayed the aging of the flies' intestines and extended their lives by as much as 50%. Dr. Walker noted that fruit flies (Drosophila melanogaster) have a life span of about two months. They start showing signs of aging after about one month, and they slow down, become less active and die. They are an excellent model for studying aging because scientists know every one of their genes and can switch individual genes on and off. “We all think about protecting the brain and the heart, but the intestine is a vital tissue type for healthy aging,” Dr. Walker said. “If anything goes wrong with the mitochondria in cells, the consequences could be devastating, and if anything goes wrong with our intestines, that may have devastating consequences for other tissue types and organs. Not only is the intestine essential for the uptake of nutrients that are a vital source of energy, but it is also an important barrier that protects us from toxins and pathogens in the environment. The intestine has to be well-maintained. He explained that the PGC-1 gene activates the cells' mitochondria and regulates mitochondrial activity in mammals and flies. The gene is a potential target for pharmaceuticals to combat age-related diseases.
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