Study finds possible secret of aging
Genetics, not wear and tear, may be the true cause of aging, according to a study by School of Medicine researchers.
Led by Developmental Biology and Genetics Prof. Stuart Kim, the study looked at 20,000 genes in C. elegans, a millimeter-long worm. Researchers monitored discrepancies in gene function over the course of the worms’ lives. They found that 1,254 genes had different levels of function depending on the worm’s age.
This suggests that certain genes, especially transcription factors — the “on-and-off-switch” genes that regulate the function of other genes — play important roles in regulating the process of aging cells. Transcription factors in worms were found to gradually disrupt the balance in cell regulation, over time turning more genes “off,” than were being turned “on.”
But the new theory doesn’t explain everything. A gene-based explanation of aging doesn’t account for vast differences in the life spans of species — this is better explained by the old molecular damage theory.
“The [old theory] is that there is damage to the proteins,” Kim said. “The differences in life spans must be how well you tolerate or repair the damage to your cells. There is a huge variation in life spans, all dependent on the same chemical reactions.” In the molecular damage theory, oxygen free radicals gradually break down the molecules within the cells of species, and this wear and tear contributes to a gradual breakdown in their ability to function.
Kim and his colleagues sought to gauge just how much genetics can affect life span when they conducted the study — the researchers took steps to find how much deterioration and genetics contributed to aging, respectively.
“We rebalanced the system [stopping altogether the function of the transcription factors],” Kim explained. “Worms lived 50 percent longer [as a result]. I don’t have the tools yet to really balance it — all I can do is knock it out.”
With the power to alter transcription factors might come the power to extend life. [KH1]Scientists could inhibit genes’ ability to control the function of cell regulation and thus control the amount of time a individual possesses a balance in cell regulation. The longer amount of time balance is achieved, the longer life is sustainable.
“Here is the next experiment,” Kim said. “Let a worm grow old so the pathways are unbalanced, and then balance the pathways [by controlling changes in transcription factors over time] and see what happens. Ask yourself the question that perhaps you not only slowed down the process of aging but you reversed it. It’s a really fascinating process, and I think we can understand it.”
Source: Stanford Daily (http://daily.stanford.edu/article/2008/7/31/studyFindsPossibleSecretOfAging)
July 31 2008 06:41 pm | Life Extension and Physical Health