A new study reveals how melanocyte stem cells are responsible for the loss of hair color with age.
- Aging but also stress are responsible for the appearance of white hair.
- This transformation is due to a blockage in the process that transforms stem cells into cells responsible for hair color.
- Deciphering this mechanism could provide new elements for a better understanding of aging in general.
White hair is often associated with aging, but the precise mechanisms behind this depigmentation were not entirely clear. A new study published in the journal Nature provides clarification by deciphering the functioning of melanocyte stem cells, which are responsible for hair color.
In the melanocyte stem cell system, dedifferentiation keeps stem cells in a dynamic nest, which is why hair whitens with age. Researchers have found that cells are responsible for hair color by continually producing and renewing it. Stem cells are mobile and can switch between stem cell and transit amplification state, which is fundamentally different from the traditional hierarchical model.
The transformation of cells responsible for hair color is blocked
During this study, researchers found that as hair ages, falls out, and regrows, melanocyte stem cells get stuck in the bulge of the hair follicle, preventing them from turning into pigment cells.
In experiments performed on mice whose hairs were aged by forced pulling and regrowth, stuck stem cells increased from 15% before the pulling out to almost 50% after the forced aging. According to the researchers, this blockage could be caused by the accumulation of defense mechanisms of the cells, which can possibly be avoided to help the hair to maintain its natural color longer.
According to Mayumi Ito, lead author of the study, “it is loss of stem cell chameleon function that may be responsible for loss of hair color“. Blocking the process that allows stem cells to change shape from an undifferentiated state to a mature pigment cell state is the cause of hair whitening. The researchers also highlighted the crucial role of interferon in blocking transformation, especially under stressful and inflammatory conditions.
Implications for anti-aging treatments
This study contributes to a better understanding of the biological processes behind hair aging and could pave the way for new treatments to prevent or reverse hair bleaching. The researchers have identified several avenues of research in this direction, in particular the development of molecules capable of neutralizing the defense mechanisms of melanocyte stem cells or even of stimulating their functioning by eliminating the obstacles which hinder their transformation into pigment cells. Much remains to be discovered about the precise mechanisms that govern the functioning of melanocyte stem cells, but this research represents a significant advance in this crucial area of biology.
This suggests the arrival of new anti-aging treatments to preserve the natural color of hair but also sheds light on the mechanisms of operation of melanocyte stem cells to better understand aging in general.
