Title: Hair Raising Tale: Nerve – Stem Cell Interactions
Abstract: Piloerection (goosebumps) requires concerted actions of the hair follicle, the arrector pili muscle, and the sympathetic nerve, providing a model to study interactions across epithelium, mesenchyme, and nerves. We show that arrector pili muscles and sympathetic nerves form a dual component niche to modulate hair follicle stem cell activity. Sympathetic nerves form synapse-like structures with hair follicle stem cells and regulate them directly through norepinephrine, whereas arrector pili muscles maintain sympathetic innervation to the stem cells. Without norepinephrine signaling, hair follicle stem cells enter deep quiescence by up-regulating quiescence regulators Foxp1 and Fgf18. Cold exposure, elevates sympathetic nerve activity, triggering both goosebumps and accelerating stem cell activation and hair growth. During development, hair follicle stem cells progeny secretes Sonic Hedgehog(SHH) to direct the formation of this muscle-nerve niche, which in turn controls hair follicle regeneration in adults. Our study reveals a reciprocal interdependence between a regenerative tissue and its niche at different stages and demonstrates sympathetic nerves can modulate stem cells through synapse-like connections and neurotransmitters to couple tissue production with environmental demands.
Host: Prof. Benjamin Podbilewicz