Novel Immune Mechanisms in Androgenetic Alopecia

This study investigates the role of the succinate receptor GPR91 in androgenetic alopecia (AGA), using human genetic data from the UK Biobank. The research identifies GPR91 as a novel immune target, with its expression in mast cells and macrophages within the perifollicular dermis of hair follicles. In AGA-affected follicles, these immune cells increase, leading to the production of cytokines that cause microinflammation and promote hair loss. The study highlights that GPR91 signaling contributes to the development of a disease-associated macrophage subtype, "trichophages," which further induces hair follicle dysfunction and miniaturization. Importantly, GPR91 inhibition by small molecule antagonists can reverse these pathological effects, suggesting GPR91 as a promising therapeutic target for preventing and reversing hair loss in AGA.