Activation of mTORC1 Signaling Is Required for Timely Hair Follicle Regeneration from Radiation Injury

A study on mice found that activation of mTORC1 signaling is necessary for timely hair follicle regeneration after radiation injury. The researchers observed that hair follicle dystrophy was induced in mice after radiation, but it was repaired within 96 hours without significant hair loss. They found that mTORC1 signaling was activated in the transit amplifying cells (TACs) compartment soon after irradiation, and its activation was maintained until the regeneration process was completed. Inhibition of mTORC1 delayed restoration of Wnt signaling in the hair matrix after radiation injury, leading to prolonged dystrophy and hair loss. The study concludes that mTORC1 signaling is required for timely regeneration of the TAC pool of hair follicles, so that hair growth can resume after radiation injury.