Kartogenin regulates hair growth and hair cycling transition

Background: Kartogenin is a heterocyclic compound able to promote the proliferation, migration, and differentiation of various cell types and induce cartilage-like tissue regeneration. However, the role of kartogenin in hair follicles (HFs), remains unknown. We therefore investigated the effects of kartogenin on the regulation of hair growth and hair growth cycle transition. Methods: The effects of kartogenin on the proliferation, cell cycle status, and migration of primary human outer root sheath cells (ORSCs) were evaluated by MTS assay, flow cytometry, Transwell^® and scratch assays, respectively. We exposed ORSCs to kartogenin (1 µM) and determined changes in mRNA and protein levels of transforming growth factor (TGF)-β2/Smad signaling molecules by reverse transcription polymerase chain reaction, western blotting, and immunofluorescence. We also examined the effects of kartogenin (10 µM) on HFs in mice by histology following cutaneous injection. Results: Kartogenin enhanced ORSC proliferation and migration function in a dose-dependent manner, and downregulated the expression of TGF-β2/Smad signaling molecules in vitro. Injection of kartogenin delayed catagen phase and increased regenerated hair length in mice in vivo. Conclusions: Kartogenin modulates HF growth and regulates the hair cycle and the TGF-β2/Smad signaling pathway, providing a potential new approach for the treatment of hair loss.