Scientists at the University of California, Irvine have discovered that all hairs can communicate with each other and grow in coordination across the entire body. They found that this process regulates via a single molecular mechanism that adjusts by skin region to ensure efficient hair growth across entire body. This mechanism is originally responsible for distinct hair densities in different body areas.

According to scientists, the mechanism could lead to new ways of addressing both balding and unwanted hair growth. It could also allow researchers to understand that how regions of faster and slower regeneration work in coordination in other fast-renewing tissues.

For the study, scientists used the first mouse model of poor hair growth to analyze human-like hair behavior that leads to baldness. During the study, scientists primarily focused on the interaction of the Wnt signaling pathway. This pathway is important for in embryonic development and regeneration, and bone morphogenetic proteins, which are hair growth inhibitory factors.

According to many previous studies, Wnt-BMP signals regulate hair growth across entire body areas. But, it was a mystery that how different skin regions communicate with one another to coordinate hairs across their borders. Lately, Wnt-BMP regulation was found to be ubiquitous across all skin.

UCI’s Maksim Plikus, assistant professor of developmental & cell biology said, “In analogy with languages spoken in two neighboring countries, it was unclear how the back skin ‘talks’ with the belly skin to coordinate the tasks of growing hairs.”

“We showed that although different signaling ‘dialects’ may exist between belly and back skin. For instance, all hairs can understand one another through the use of similar ‘words’ and ‘sentences.”

If communication between nonbalding and balding regions can be reactivated, hair growth signals can then start spreading across the entire head skin. Thus, it can prevent regional baldness. Just like scalp skin can show hair growth deficiency, skin in other body sites such as the face, arms, and legs can often show excessive hair growth that can be cosmetically undesirable.

The study suggests that increased signaling crosstalk among hair follicles could be one major reason for this. It also suggests that types of Wnt-BMP signaling levels that are very favorable for hair growth and the types that prevent it.

Plikus said, “The findings point toward additional signaling factors besides Wnt and BMP positively correlated with robust hair growth. Studying these will be the researchers’ next step.”

Qing Nie, professor of mathematics said, “The experiments can be insufficient to study complex biological functions, such as hair growth across entire body. In such cases, mathematical modeling can greatly assist in the discovery process.”

“Our new mathematical model predicted details of signaling communications between hairs, otherwise difficult to reveal with standard biological experiments alone.”

REFERENCEUCI News
JOURNAL REFERENCEDOI: 10.7554/eLife.22772
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