TLR2 Regulates Hair Follicle Cycle and Regeneration via BMP Signaling

The study explores the role of Toll-like receptor 2 (TLR2) in hair follicle (HF) cycle regulation and regeneration via BMP signaling. It shows that TLR2, activated by the PUFA metabolite CEP, promotes hair regeneration and growth, with TLR2 levels declining with age and obesity. TLR2 is essential for HF stem cell (HFSC) activation and hair cycle progression, as its deletion delays the onset of the anagen phase. TLR2 knockout mice exhibited prolonged telogen phases and reduced HFSC proliferation due to elevated BMP signaling, which Noggin, a BMP antagonist, could reverse. The findings suggest targeting TLR2 and its ligands could be a therapeutic strategy for treating hair loss and enhancing hair regeneration.