A new study in mice examines why muscles lose strength with age and why exercise helps. The researchers focused on a protein-control complex called mTORC1, which normally builds and repairs muscle but can become chronically overactive during aging. They identify a gene regulator, DEAF1, as a key factor that drives mTORC1 into an unhealthy, high-activity state.
The scientists report that DEAF1 increases protein production in muscle cells while preventing the removal of damaged proteins. Over time this imbalance can damage muscle cells and contribute to sarcopenia, the age-linked loss of muscle mass and function. To test the role of activity, the team put aging mice through endurance workouts that included an exhausting treadmill run and compared them with sedentary older mice.
After exercise, the active mice showed large reductions in mTORC1 activity. Further analysis showed that exercise activates FOXO genes, which suppress DEAF1 and help return mTORC1 toward normal activity. The authors suggest drugs that reduce DEAF1 or boost FOXO could mimic some exercise benefits and help prevent age-related muscle weakening.
Difficult words
- complex — group of connected parts that work together
- regulator — something that controls a process or system
- chronically — over a long period, repeatedly or continuously
- overactive — more active than normal, often causing problems
- imbalance — situation where things are not in correct proportion
- sarcopenia — age-related loss of muscle mass and strength
- endurance — ability to do hard activity for long time
- sedentary — involving little or no physical activity
- suppress — to stop or reduce the activity of something
Tip: hover, focus or tap highlighted words in the article to see quick definitions while you read or listen.
Discussion questions
- Do you think drugs that reduce DEAF1 could replace exercise to prevent muscle weakening? Why or why not?
- What types of exercise do you think are most helpful to keep muscles strong as people age? Explain briefly.
- If someone is sedentary now, what small weekly changes could help improve their muscle health?
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