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Many of the physical benefits that come with regular exercise may be mediated by a single protein group called Sestrin, according to a new study in the journal Nature Communications. What’s more, by altering the amount of Sestrin present in the body, it may be possible to burn fat and increase endurance without having to break into a sweat.
Previous research has indicated that Sestrin tends to build up in muscles after a workout, although the role of this protein had never been fully understood. To investigate, a team of researchers created a line of fruit flies that had been genetically engineered to lack the ability to produce Sestrin. These flies were then placed in vials that dropped every 15 seconds, causing them to repeatedly climb or fly back up to the top of their container – kind of like a treadmill for flies.
After three weeks of training in their insect gym, normal flies displayed an increase in their performance levels and were able to maintain a higher intensity for longer periods. In contrast, the flies that lacked Sestrin showed no improvement at all, suggesting that the molecule must in some way generate changes in endurance levels following exercise.
Another line of flies was then genetically engineered to overexpress Sestrin, to the point that their muscles were so full of it that they couldn’t produce any more. Without needing to exercise, these flies displayed significantly higher performance levels than regular flies, again indicating that Sestrin in some way enhances physical capacities. Because these flies couldn’t produce any more Sestrin than they started with, the researchers were unsurprised to see that the insects made no further gains after exercise.
The team then repeated the experiment with mice, producing a strain of rodents that lacked the ability to produce Sestrin. Compared to normal mice, these mutants were unable to burn fat, increase their aerobic capacity, or improve their respiration following a period of regular exercise on a running wheel.
All of these findings point to the possibility of one day using Sestrin to help reduce muscle wasting in humans without the need for exercise. While the anti-doping authorities would surely ban athletes from engaging in such a practice, it could be used to help heal muscular decline in elderly people.
However, a lot more work will have to be conducted before Sestrin-based treatments are declared safe and effective. On top of that, study author Jun Hee Lee mentioned in a statement that a method for delivering Sestrin to the body has yet to be developed, explaining that “Sestrins are not small molecules, but we are working to find small molecule modulators of Sestrin.”
