Hairy moles could be the key to curing baldness; at least, that is what a study from the University of California, Irvin suggests, which ensures that these skin spots contain a protein that acts as a powerful hair growth activator. The discovery may offer a roadmap for a whole new generation of molecular therapies for androgenetic alopecia, a common form of hair loss in both women and men.
The research, published in the journal Nature, describes the essential role that osteopontin and CD44 molecules play in activating hair growth within hairy skin moles or nevi. These nevi accumulate particularly large numbers of senescent pigment cells, yet show very robust hair growth.
“We found that senescent pigment cells produce large amounts of a specific signaling molecule called osteopontin, which causes tiny, normally inactive hair follicles to activate their stem cells for robust growth of long, thick hairs”, the researcher said in a statement. Lead author MaksimPlikus, Professor of Developmental and Cell Biology. “Senescent cells are generally considered detrimental to regeneration and are believed to drive the aging process as they accumulate in tissues throughout the body, but our research clearly shows that there is a positive side to cellular senescence“.
Hair follicle growth is well regulated by stem cell activation; these cells divide, allowing the follicles to produce new hair in a cyclical fashion. After each period of hair growth, there is a latency period, during which the follicle stem cells lie dormant until the next cycle begins.
Hyperactivated hair stem cells
The study involved mouse models with pigmented skin spots that had hyperactivated hair stem cells and exhibited accelerated hair growth, much like clinical observations documented in human hairy skin nevi. Further analysis of senescent pigment cells and nearby hair stem cells revealed that the former produced high levels of a signaling molecule called osteopontin, for which the hair stem cells had a corresponding receptor molecule called CD44. Following the molecular interaction between osteopontin and CD44, hair stem cells were activated, resulting in strong hair growth.
To confirm the major role of osteopontin and CD44 in the process, mouse models lacking either of these genes were studied; exhibited significantly slower hair growth. The effect of osteopontin on hair growth has also been confirmed through samples of hairy skin moles collected from humans.