NF-κB Participates in Mouse Hair Cycle Control and Plays Distinct Roles in the Various Pelage Hair Follicle Types

The study investigated the role of the transcription factor NF-κB in the hair follicle (HF) cycle of adult mice. Using NF-κB reporter mouse models, researchers found strong NF-κB activity in the secondary hair germ during late telogen and early anagen phases, indicating its role in HF stem/progenitor cell activation. NF-κB activity was also observed in the inner root sheath and HF matrix during mid-anagen, suggesting involvement in hair fiber morphogenesis. An inducible NF-κB suppression model revealed that NF-κB functions varied by hair type: it was crucial for the telogen-anagen transition in awl and zigzag HFs, necessary for zigzag hair bending via noncanonical signaling, and essential for guard HF cycling, highlighting its importance in stem cell activation and maintenance.