Mouse Study Finds Molecule That Tells Hair to Grow

Aug. 1 -- THURSDAY, July 31 (HealthDay News) -- Scientists have taken a step forward in understanding the mechanisms behind a problem that has bedeviled many men, and some women, for all of history: hair loss.

The study identifies a key signaling molecule that tells hair follicles to start the hair-growing cycle.

"These are very complex molecular signals, and the authors have very nicely shown that there is one molecule, laminins 511, that is a very important signal to tell the hair molecule to move through the process. It's part of a basic biological understanding," said Dr. Ronald Crystal, chairman of genetic medicine at New York Presbyterian Weill Cornell Medical Center in New York City.

The researchers, reporting in the Aug. 1 issue of Genes & Development, feel the findings may one day hold the key to treating male-pattern baldness, as well as hair loss from chemotherapy or even to restore hair on burn victims.

But, as so often happens, the study was conducted in mice and, as Crystal pointed out, "Mice are not just little men and women. They are different than us and also different in their hair."

A series of complex molecular signals tell hair follicles to go through a cycle of follicle growing, hair growing, follicle receding and hair receding, Crystal explained.

The same group of researchers had previously found that the protein laminin-511 was important to hair development.

In this study, the authors found out why. It was originally thought that laminin-511 was made from the cells of the outer layer of the skin (epithelium) and acted on the epithelium.

It now turns out, however, that the protein, although produced by the epithelium, actually penetrates into the inner layer of the skin (dermis) to kick start the hair-growing process.

"So laminin-511 is an early epithelial message to the dermis to say let's start producing hair," said study senior author Dr. Peter Marinkovich, an associate professor of dermatology at Stanford University School of Medicine and member of the Stanford Cancer Center. "Hair is formed as a result of cooperation and communication between the two layers."