According to Qi Sun, the lead researcher in charge of the study, there is now “potential to reverse or prevent graying of human hair by helping stuck cells to move between developing hair follicle compartments again.”
Scientists may have found the reason why our hair turns gray as we age. A new study suggests that stem cells could get stuck and lose their ability to maintain hair color as hair ages. Certain stem cells, capable of developing into different cell types, have a unique ability to move between hair follicle growth compartments. It is these cells that lose their ability to move with age, setting the stage for gray hair. The research, led by the Grossman School of Medicine at New York University (NYU), focused on mouse skin cells, also found in humans, called melanocyte stem cells (McSCs). The scientists suggested that if their findings apply to humans as well, it could pave the way for a method to reverse or prevent graying hair.
Hair color is controlled by the continuous multiplication of McSCs inside hair follicles, thereby enabling the signaling necessary for the maturation of cells that produce the pigments responsible for color. The study, published in the journal Nature, found that during normal hair growth, these cells constantly move from one compartment to another in the developing hair follicle. It is within these compartments that McSCs are exposed to cues that influence their maturity. According to the findings, as hair ages, falls out and regrows, an increasing number of McSCs get stuck in the compartment called the “hair follicle bulb”. They remain there, do not mature and do not return to their original location in the compartment, where they would have been stimulated to regenerate into pigment cells.
Qi Sun, postdoctoral researcher at NYU Langone Health in New York and principal investigator in charge of the study, said, “Our study deepens our understanding of how melanocyte stem cells work to color hair. The newly discovered mechanisms raise the possibility that fixed positioning of melanocyte stem cells also exists in humans. If so, this has potential to reverse or prevent graying of human hair by helping stuck cells move between follicle compartments again developing hair.”
Mayumi Ito, principal investigator of the study and professor in the Ronald O. Perelman Department of Dermatology and Department of Cell Biology at NYU Langone Health, said, “It is the loss of chameleon function of melanocyte stem cells that could be responsible for graying and loss of hair color.”
The researchers plan to investigate ways to restore the movement of McSCs or physically move them back to their germinal compartment, where they can produce pigment.