The Mystery of Hair Growth, Untangled

The amount of hair on a person's head is dictated by how hair follicles communicate, a mechanism recently discovered by a Pew biomedical scholar and his team.

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Hair follicles on the body correspond with each other, according to a new study by 2016 Pew biomedical scholar Maksim Plikus, Ph.D., of the University of California, Irvine. Plikus’ research has shown that follicles throughout the human body communicate via a major signaling pathway that helps to dictate when and where hair should grow. The hairs on different parts of our body grow to specific lengths and adjust their growth patterns to ensure that vulnerable areas remain adequately covered—necessary if animals are to survive frigid temperatures.

While it has been known that a particular growth pathway is responsible for dictating hair growth cycles, it was largely unclear how different regions of the skin communicate and coordinate these patterns. For example, how do the back and the front of the body synchronize growth to make sure that hair develops at the same rate and time?  

Plikus and his team developed a mouse model to tease out how hair growth across the body is controlled. In collaboration with another group of scientists that specializes in mathematical modeling, they found that hair follicles use a well-known developmental pathway—Wnt-BMP—to communicate with other parts of the body to regulate hair growth. This finding demonstrates that the body has processes in place that allow coordination among different regions of hair growth. When this correspondence breaks down, it could lead to baldness or unnecessary hair. Notably, Plikus’ group also found that the level of Wnt-BMP signaling can be tuned or adjusted to stimulate or inhibit hair growth, leading to the potential for adjusting hair growth patterns in humans.

This groundbreaking study is a first step in identifying mechanisms that could contribute to abnormal hair growth. Researchers may be able to use this information to develop pharmacological agents that manipulate this pathway to combat baldness as well as unwanted hair. 

Kara Coleman directs The Pew Charitable Trusts’ biomedical programs, including the biomedical scholars, Pew-Stewart Scholars for Cancer Research, and Latin American fellows programs.