Researchers at New York University's Langone Medical Center have identified the communication pathway between hair follicles and melanocyte stem cells that regenerates pigmented hair.
According to the study, published in the June 10, 2011, issue of Cell and led by Mayumi Ito, PhD, melanocyte stem cells (McSCs) intimately interact with epithelial stem cells (EpSCs) in the hair follicle bulge and secondary hair germ (sHG) and undergo activation and differentiation to regenerate pigmented hair. However, the mechanism behind this stem cell behavior was not known.
Using genetic mouse models, researchers found that Wnt signaling is a key pathway that couples the behavior of the stem cells. Specifically, Wnt activation in McSCs reportedly drives their differentiation into pigment-producing melanocytes, while EpSC Wnt signaling not only dictates hair follicle formation, but also regulates McSC proliferation during hair regeneration.
Research also showed that the depletion of, inhibition of, or even abnormal Wnt signaling in the hair follicle stem cells inhibits hair re-growth and prevents the activation of melanocyte stem cells required for producing hair color. Further, the lack of Wnt activation in melanocyte stem cells leads to depigmented or gray hair.
This study suggests that Wnt signaling is a key pathway for the regulation of melanocyte stem cells; it also finds that melanocyte behavior is associated with hair regeneration. Thus, according to this research, manipulating Wnt signaling may be a strategy for addressing pigmentation issues such as graying hair. It may also lead to a model for tissue regeneration or potential treatments to regenerate hair.