Recombinant Type XVII Collagen Promotes Hair Growth by Activating the Wnt/β-Catenin and SHH/GLI Signaling Pathways

(1) Background: As society progresses, increasing numbers of individuals are experiencing hair loss, which can be attributed to factors such as unhealthy diets, insufficient sleep, stress, and hormonal imbalances. Currently available pharmacological treatments for hair loss often cause undesirable side effects, highlighting the urgent need to explore safer and more effective agents to promote hair restoration. This study investigated the role of recombinant human type XVII collagen derived from the α1 chain (rhCOL17A1) in facilitating hair growth and restoration. (2) Methods: We analyzed the impact of rhCOL17A1 on the mRNA expression of several growth factors, as well as Bcl-2 and Bax, at the cellular level. Moreover, the effects of rhCOL17A1 on the expression of key proteins in the Wnt/β-catenin and Sonic Hedgehog (SHH)/GLI signaling pathways were examined by Western blotting (WB). At the organismal level, we established a model in C57BL/6 mice through chronic subcutaneous administration of 5% testosterone propionate. We subsequently assessed the effect of rhCOL17A1 on hair regrowth via histological analysis using hematoxylin and eosin (H&E) staining and immunofluorescence staining. (3) Results: rhCOL17A1 contributes to the resistance of hair follicle dermal papilla cells (HFDPCs) to apoptosis. rhCOL17A1 activates the Wnt/β-catenin and SHH/GLI signaling pathways, and increases the expression of type XVII collagen (COLXVII), thereby creating a favorable environment for hair growth. Furthermore, rhCOL17A1 exerts a significant growth-promoting effect at the animal level. (4) Conclusions: rhCOL17 promotes hair growth by activating the Wnt/β-catenin and SHH/GLI signaling pathways and upregulating COLXVII expression.