Hair Formation, Skin Stem Cells And BMP Signaling

Main Category: Dermatology
Also Included In: Stem Cell Research;  Genetics;  Biology / Biochemistry
Article Date: 15 Feb 2008 - 4:00 PDT

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The February 15th cover story of G&D reports on the recent discovery by Dr. Elaine Fuchs and colleagues at the Rockefeller University that BMP signaling in dermal papilla cells is important for hair follicle formation.

The dermal papilla (DP) is a small cluster of mesenchymal cells that exist at the base of the hair follicle, and instruct nearby epithelial stem cells to induce hair follicle growth. But because DP cells are so few in number, and loose their hair-inducing potential in culture, the details of this molecular conversation have remained elusive.

Dr. Fuchs' team developed a clever genetic strategy to delete specific genes of interest in DP cells, and then graft these genetically engineered cells onto the backs of immunocompromised (and bald) mice, to study the effect of gene deficiency on hair growth.

The researchers found that deletion of the receptor for the bone morphogenetic protein 1a (BMPR1a) in DP cells prevented the formation of hair follicles in engrafted mice. However, if BMPR1a is intact in DP cells, and a bit more BMP protein is added to the cells, then the DP-stem cell cross-talk is prolonged, and recipient mice grow a tuft of hair on their otherwise bald backs.

"Several years ago, we devised a method to purify the cells and characterize the genes expressed by the DP and its neighboring cells that make hair," says Fuchs. "This gave us clues that BMP signaling might be important in specifying the unique hair-inducing properties of DP cells. We've now succeeded in testing this possibility and our findings are important not only for our understanding of the mesenchymal-epithelial crosstalk that is so critical for hair production, but also for developing new and improved methods for stimulating hair growth."

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Source: Heather Cosel
Cold Spring Harbor Laboratory

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