Untreated mouse skin showing no hair growth, left, compared to mouse skin treated with the drug UK5099, right, showing hair growth. Photo courtesy UCLA Broad Stem Cell Center/Nature Cell Biology
Aug. 14 (UPI) -- Researchers at the University of California, Los Angeles say in a study they have identified a new way to activate stem cells in hair follicles to regrow hair.
The study, published today in Nature Cell Biology, findings could lead to new drugs that could promote hair growth for people with baldness or alopecia.
Hair follicle stem cells are quiescent, meaning they are inactive except during a new hair cycle when they activate to grow hair. The quiescence is regulated by several factors and failure to activate leads to hair loss.
UCLA researchers found that hair follicle stem cell metabolism differs from other cells of the skin in that they consume glucose from the bloodstream and process the glucose to produce a metabolite called pyruvate. The cells then either sent pyruvate to their mitochondria or convert it to lactate.
"Our observations about hair follicle stem cell metabolism prompted us to examine whether genetically diminishing the entry of pyruvate into the mitochondria would force hair follicle stem cells to make more lactate, and if that would activate the cells and grow hair more quickly," Healther Christofk, an associate professor of biological chemistry and molecular and medical pharmacology at UCLA, said in a press release.
Researchers blocked the production of lactate genetically in mice and found that this prevented hair follicle stem cell activation and then increased lactate production genetically in the mice, which accelerated hair follicle stem cell activation.
"Before this, no one knew that increasing or decreasing the lactate would have an effect on hair follicle stem cells," William Lowry, a professor of molecular, cell and developmental biology, said. "Once we saw how altering lactate production in the mice influenced hair growth, it led us to look for potential drugs that could be applied to the skin and have the same effect."
Researchers identified two drugs that influenced hair follicle stem cells in mice, RCGD423 and UK5099.
RCGD423 activates a cellular signalling pathway known as JAK-Stat, which transmits information form outside the cell to the nucleus.