Research from Duke-NUS Medical School, in collaboration with Singapore General Hospital and Cardiff University, reveals that exercise not only builds muscle but also plays a crucial role in reversing muscle aging. The study identifies a cellular mechanism that enhances the repair and growth capabilities of muscles in older individuals, potentially mitigating mobility and strength decline associated with aging.
As people age, muscle function typically deteriorates, leading to increased risks of falls, slower recovery from injuries, and poor blood sugar regulation. The research team discovered that the key to maintaining muscle function lies in a growth pathway known as mTORC1. This pathway is responsible for overseeing protein production and maintaining tissue health. However, as individuals grow older, the balance of this pathway is disrupted, resulting in the accumulation of damaged proteins that contribute to muscle weakness.
Understanding the Mechanism Behind Muscle Aging
The research pinpointed a transcription factor named DEAF1 as a significant contributor to this imbalance. DEAF1’s activity increases with age, leading to overactivity in the mTORC1 pathway. This disrupts the normal protein exchange that helps maintain muscle strength in younger individuals. Regulatory proteins known as FOXOs typically help manage DEAF1 levels, but their effectiveness diminishes with age.
“Exercise can reverse this process, correcting the imbalance,” stated Tang Hong-Wen, an associate professor at Duke-NUS. Physical activity activates proteins that lower DEAF1 levels, restoring balance to the growth pathway. This restoration enables aging muscles to eliminate damaged proteins and rebuild effectively, enhancing overall strength and resilience.
Despite these findings, researchers caution that high DEAF1 levels or muted FOXO activity may hinder the ability of exercise alone to restore muscle power. This variability could explain why some older adults experience significant benefits from physical activity while others do not.
Implications for Older Adults
According to Priscillia Choy Sze Mun, lead author of the study, “Exercise tells muscles to ‘clean up and reset.'” Lowering DEAF1 levels allows older muscles to regain strength and balance, akin to hitting a rewind button. With millions of older adults at risk of muscle decline, understanding DEAF1 could pave the way for innovative strategies to protect muscle health and enhance quality of life.
The study utilized older mice and fruit flies as models, revealing consistent patterns across both species. Increasing DEAF1 levels led to greater muscle weakness, while reducing its activity restored balance and promoted muscle repair. These findings suggest that humans may experience similar age-related dysregulation in muscle tissue.
Manipulating DEAF1 levels could be a promising approach to ensuring that the benefits of exercise are sustained well into older age, even for those who may not engage in extensive physical activity. “This study helps explain, at a molecular level, why aging muscles lose their ability to repair themselves and why exercise can restore that balance in some individuals,” noted Patrick Tan, a professor at Duke-NUS.
This significant research was published in the journal PNAS, highlighting the importance of DEAF1 as a key regulator in muscle repair processes. The findings may lead to new interventions aimed at enhancing the health and mobility of aging populations worldwide.
