It’s Black and White: Preventing radiation-induced hair graying

Abstract

Melanocyte stem cells (MeSCs) and their differentiated melanocyte progeny are responsible for providing pigment to the hair and skin. Dysfunction of MeSCs, therefore, can result in white hair formation and occurs for a variety of reasons, including aging, stress, and DNA damage. While mice typically develop white hairs within weeks following radiation-induced DNA damage, we discovered that treatment with prostaglandin E2 (PGE2) prevents radiation-induced hair graying. Following irradiation, vehicle injected mice displayed a drastic decrease in MeSC numbers, and treatment with PGE2 prevented this loss of MeSCs. We found that PGE2 prevents DNA damage and premature differentiation of MeSCs, which is known to drive MeSC loss and deplete the stem cell pool. To understand how PGE2 prevents MeSC loss and radiation-induced hair graying, we used receptor agonists to determine that PGE2 is acting through the prostaglandin EP3 receptor. Surprisingly, we found that PGE2 is acting through sensory nerves to protect MeSCs, as celltype specific knockout of EP3 on sensory nerves prevented the protective abilities of PGE2. In this study, we demonstrate that PGE2 prevents radiation induced hair graying by protecting MeSCs from loss. While sensory nerves in the skin are classically thought to mediate our sensations of touch, pain, and heat, here we uncover a previously unknown function of sensory nerves to regulate and protect MeSCs.