Study Links Grey Hair in Mice to Cellular Process

A study in mice has identified a process in which melanocyte stem cells respond to specific types of DNA damage by maturing and exiting the stem cell pool, resulting in grey hair. The research, published in a peer-reviewed journal, focused on double-strand breaks in DNA within these pigment-related cells located in hair follicles.

Melanocyte stem cells normally replenish pigment-producing cells that give hair its color. When these stem cells sustain certain DNA damage, they undergo seno-differentiation, a process that converts them into mature pigment cells that then leave the stem cell population.

This removal prevents damaged cells from accumulating mutations that could lead to cancer.

The study also tested melanocyte stem cells exposed to cancer-causing chemicals and ultraviolet radiation. Under these conditions, the cells bypassed seno-differentiation and instead received signals to continue dividing despite carrying genetic damage, creating conditions that can lead to melanoma.

Researchers described the two outcomes as antagonistic fates for the same stem cell population. The findings suggest that grey hair can result from a protective mechanism that eliminates risky cells, while certain environmental stressors may override this mechanism and allow damaged cells to persist.

The experiments were conducted in mice. The authors noted that further research is required to determine whether the same mechanisms operate in human melanocyte stem cells.