New Research Provides Clues on Why Hair Turns Grey
New York, NY – A new study by researchers at NYU Langone Medical Center has shown that Wnt signalling, already known to control many biological processes, between hair follicles and melanocyte stem cells can dictate hair pigmentation. The study was published in the June 11, 2011 issue of the journal Cell.
The research was led by Dr. Mayumi Ito, assistant professor in the Ronald O. Pereleman Department of Dermatology at NYU Langone. “We have known for decades that hair follicle stem cells and pigment-producing melanocycte cells collaborate to produce coloured hair, but the underlying reasons were unknown,” said Dr. Ito. “We discovered Wnt signalling is essential for coordinated actions of these two stem cell lineages and critical for hair pigmentation.” The study suggests the manipulation of Wnt signalling may be a novel strategy for targeting pigmentation such as greying hair. The research study also illustrates a model for tissue regeneration.
“The human body has many types of stem cells that have the potential to regenerate other organs,” said Dr. Ito. “The methods behind communication between stem cells of hair and colour during hair replacement may give us important clues to regenerate complex organs containing many different types of cells.”
Using genetic mouse models, researchers were able to examine how Wnt signalling pathways enabled both hair follicle stem cells and melanocyte stem cells to work together to generate hair growth and produce hair colour. Research also showed the depletion (or inhibition or abnormal) Wnt signalling in hair follicle stem cells not only inhibits hair re-growth but also prevents melanocytes stem cell activation required for producing hair colour. The lack of Wnt activation in melanocyte stem cells leads to depigmented or grey hair.
The study raises the possibility that Wnt signalling is a key pathway for the regulation of melanocyte stem cells and shows how melanocyte behaviour is associated with hair regeneration. This insight provides further understanding of diseases in which melanocytes are either appropriately lost such as hair greying or undergo uncontrolled cell growth as in melanoma