UT Southwestern research sheds light on baldness

Investigators, including Chung-Ping Liao, Reid C. Booker, Sean J. Morrison and Lu Q. Le from the University of Texas Southwestern Medical Center (UT Southwestern), have stumbled upon a finding that may lead to a cure for balding and hair graying.

The study, “Identification of hair shaft progenitors that create a niche for hair pigmentation,” appears in an advance online publication by the journal Genes & Development.

Baldness and gray hair are considered unfortunate but unavoidable products of aging. Generally, the risk of losing your hair is proportional to your age. Apparently, men are more prone to baldness than women. The American Hair Loss Association says that two-thirds of men will experience some degree of balding by age 35, and up to 85% of men will have noticeably thinner hair by age 50.

Hair is produced by the hair follicle, a skin organ that contains several structures including papilla, matrix, and bulge. Hair differentiates from follicle stem cells and is also pigmented by melanocytes in the follicle. However, the precise mechanism is not fully understood.

When UT Southwestern investigators studied how tumors form, they unexpectedly found why hair turns gray. They observed that a protein called KROX20 switches on in skin cells that develop into the hair shaft. These pre-hair cells then produce a protein called SCF, which the investigators showed is important for giving hair its color. The investigators said that SCF expression by these cells is necessary for the maintenance of differentiated melanocytes and for hair pigmentation.

KROX20, also known as EGR2, is a transcription factor that has been associated with nerve development. SCF, or stem cell factor, is a cytokine that plays a role in hematopoiesis, spermatogenesis, and melanogenesis.

When the investigators deleted the SCF gene in the pre-hair cells of mouse models, the mice's hair turned white. When they deleted the KROX20-producing cells, the mice became bald. This may help explain the mechanism of balding and hair graying. “Our findings reveal the identities of hair matrix progenitors that regulate hair growth and pigmentation, partly by creating an SCF-dependent niche for follicular melanocytes,” the investigators concluded. These findings may open new avenues for the development of therapies for baldness and hair graying. In the future research, the investigators will work to determine if the mouse findings are relevant to human balding and hair graying. (Cusabio offers KROX20, SCF, and Recombinant FGFR1 for research.)