Like many cat owners, I like to talk to my cats for no reason. As I was playing with my cat one day, I shouted at him "what a good baby boy!" My boyfriend immediately corrected me and said, " you know he is a middle age man in human years right?" Turns out my cat is 33 years old in human age! But since cats have a different life history than human, sometimes it is easy to forget my snuggle muffin is a middle age man. The difference in life history between organisms evolve over millions of years and genetics seems to have played an important role. But what if we could now genetically alter our lifespan?
In a recent research conducted by MDI Biological Laboratory, in collaboration with scientists from the Buck Institute for Research on Aging in Novato, Calif., and Nanjing University in China, scientists discovered 2 synergistic cellular pathways for longevity that amplify lifespan fivefold in C. elegans. C. elegans is a nematode worm with a life span of 3-4 weeks, which means they finish their entire life cycle from infancy to old age within this period. Through altering 2 specific genes, DAF-2 and RSKS-1, scientists are able to alter the insulin signaling (IIS) and TOR pathways in C. elegans.
These 2 signaling pathways are associated with the mitochondrial activity across organisms, since these gene are "conserved". This means that these 2 genes have been passed down from our very early common ancestor since the beginning of evolution. By genetically altering these pathways, scientists have "tricked" cells into thinking that they are starving thus they will work harder to maintain their regular activities.
Result shows that altering IIS pathway alone yields a 100% increase in lifespan and TOR pathway yields a 30% extension in lifespan. Scientists expected to see a 130% increase in lifespan in C. elegans after genetically altering the 2 pathways together. Instead, they find a 500% increase, which is the equivalent of living to 400-500 years old in human. So what does this mean to human longevity?
Death by old age in human is generally connected to age-related diseases. As human age, cells do not function the same way they used to and the rate of diseases such as cancer and Alzheimer's increases. Scientists found that genetically altered C. elegans not only extended their lifespan, they also lived healthily. Lead author of this study, Jianfeng Lan, Ph.D. explains in the news article "Our findings demonstrate that nothing in nature exists in a vacuum; in order to develop the most effective anti-aging treatments we have to look at longevity networks rather than individual pathways."
Scientists in this study seem to be hopeful to find a cure to old age in human. In fact, the private sector has already started to launch various genetic treatments that they claim could extend human life, starting at $1m. So there is clearly a desire and demand for reverting the course of life cycle in human. But the consequences of these treatments may be far beyond our wildest imagination and serious caution has to be taken when dealing with matters such as engineering human life history.
Pathways that extend lifespan by 500 percent identified
Discovery of cellular mechanisms could open door to more effective anti-aging therapies
https://www.sciencedaily.com/releases/2020/01/200108160338.htm
Monica Cheung—Feb 17th, 2020
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