Topic: Biology

Researchers at UCLA found that older mice have slower muscle healing due to a protein called NDRG1. This protein helps stem cells survive longer but makes them less functional.

Muscle aging is a frustrating reality for many older adults. New research from the University of California, Los Angeles (UCLA) has shed light on why muscles age slower in older mice. The study found that as muscles age, their stem cells build up high levels of NDRG1, a protein that makes them slower to switch on and repair damaged tissue.

The researchers, led by Dr. Thomas Rando, compared muscle stem cells from young and old mice. They discovered that NDRG1 increased sharply with age, reaching levels 3.5 times higher in older cells than in younger ones. This protein acts like a brake inside the cell, dampening a signaling pathway called mTOR, which normally drives cells to activate, grow, and repair tissue.

To determine whether NDRG1 was responsible for slower healing, the scientists allowed mice to age naturally to the equivalent of about 75 human years. They then blocked the activity of NDRG1. Once this protein was inhibited, the older muscle stem cells began behaving more like young ones, activating more quickly and repairing injured muscle faster.

However, there was a downside. When NDRG1 was blocked, fewer muscle stem cells survived over time. As a result, the muscle's ability to regenerate after repeated injuries was reduced.

Why It Matters

This discovery can help us understand why older adults may take longer to recover from injuries or illnesses. It also highlights the importance of finding ways to balance long-term survival with immediate regenerative capacity in stem cells.

Key Facts

• Aging muscles have slower muscle healing due to high levels of NDRG1 protein
• NDRG1 acts like a brake, dampening mTOR signaling pathway
• Blocking NDRG1 activity makes older muscle stem cells behave more like young ones

Key Terms

mTOR

A signaling pathway that drives cell activation, growth, and repair

Implications

This discovery can help us understand why older adults may take longer to recover from injuries or illnesses. It also highlights the importance of finding ways to balance long-term survival with immediate regenerative capacity in stem cells.