Researchers from the University of Michigan suggest that the naturally occurring Sestrin protein appears to mimic the effects of exercise on flies and mice in their experimental trials. Their findings published in Nature Communications have far reaching implications across many fields, for example in the future this may be of benefit to those who are unable to exercise due to health issues, old age, or problems with muscles.
“Researchers have previously observed that Sestrin accumulates in muscle following exercise,” explains Myungjin Kim, Ph.D., a research assistant professor in the Department of Molecular & Integrative Physiology, in a release.
To further explore the connection between exercise and Sestrin the team designed a version of a fly treadmill in which a group of flies were trained three weeks to climb up and out of a test tube; some of the flies were normal control subjects while others were specifically bred to lack the ability to produce Sestrin.
“Flies can usually run around four to six hours at this point and the normal flies’ abilities improved over that period,” says professor Jun Hee Lee, Ph.D. “The flies without Sestrin did not improve with exercise.”
When another group of untrained normal flies was provided the maximum dose of Sestrin the flies were observed to become immediately more adept at the exercises and were physically superior to other flies, even those that spent weeks training. The flies given the max dose did not appear to get in any better shape after exercising, indicating that Sestrin alone effectively caused them the reach full physical potential, according to the researchers.
For another portion of the study mice were also bred to not be able to produce Sestrin: Typically normal mice should demonstrate respiration, fat burning, and aerobic capacity improvement with exercise, but this group of nice had no improvements after training.
“We propose that Sestrin can coordinate these biological activities by turning on or off different metabolic pathways,” Lee explains. “This kind of combined effect is important for producing exercise’s effects.”
Another portion of the study found that muscle specific Sestrin is capable of preventing atrophy in immobilized muscle groups which often occurs when a limb is placed in a cast for months at a time.
Although these findings are remarkable, the authors note that there still is a great deal of work to do before Sestrin will be ready for humans, so it won’t be hitting the selves as a supplement any time soon. For now the researchers top priority is to identify how exactly exercise produces Sestrin within the body.
“Sestrins are not small molecules, but we are working to find small molecule modulators of Sestrin,” Lee says. “This is very critical for future study and could lead to a treatment for people who cannot exercise,” Kim concludes.
