Yale Scientists discover the signal source for hair growth

In a research published in the Sept. 2 issue of the journal Cell, researchers at Yale provide insights for developing new treatments for baldness as they have discovered the signal source that stimulates hair growth.

In mice, researchers found that hair growth was initiated by molecular signals from stem cells within the fatty skin layer.

Study senior author, and assistant professor of molecular, cellular, and developmental biology, Valerie Horsley said, “If we can get these fat cells in the skin to talk to the dormant stem cells at the base of hair follicles, we might be able to get hair to grow again.”

Although stem cells exist in the follicle roots of men with male pattern baldness, the stem cells lose their potential to stimulate hair regeneration. While scientists are aware that follicle stem cells demand signals within the skin to stimulate hair growth, the signal source has been indistinct.

As per an observation by Horsley’s team, hair death causes the fat layer in the scalp to shrink. In contrast, hair re-growth causes the fat layer to swell up through a process called adipogenesis. In the mouse model, researchers found that hair regeneration required adipose precursor cells, a type of stem cells involved in the formation of new fat cells. Researchers also found that hair growth required molecules called platelet derived growth factors (PDGF) produced by these stem cells.

Horsley’s lab has embarked upon understanding hair growth regulation by trying to identify other signals produced by adipose precursor stem cells. They further want to understand whether human hair growth would require the same signals.
The paper was authored by lead author Eric Festa, Jackie Fretz, Ryan Berry, Barbara Schmidt, Matthew Rodeheffer, and Mark Horowitz from Yale. The National Institutes of Health and the Connecticut Stem Cell Research Program funded the research.