FGF7 secreted from dermal papillae cell regulates the proliferation and differentiation of hair follicle stem cell1

Hair follicle stem cell (HFSC) capable of self-renewal and differentiation in hair follicle is an undeveloped stem cell model for regenerative medicine. The interaction between HFSC and dermal papilla cell (DPC) determines hair follicle development. FGF7 is a paracrine protein of epithelial proliferation, differentiation and migration. The single-cell transcriptome profiling and immunofluorescence results showed that FGF7 localized at DPC, while FGF7 receptor (FGFR2) expressed in both DPC and HFSC. By co-culturing HFSC and DPC, we found that FGF7 secreted from DPC could promote the proliferation of DPC and HFSC via Wnt signaling pathway and induce the differentiation of HFSC. Additionally, CUT&Tag assay revealed a genomic colocalization between FGF7 and pluripotency-related genes and GSK3β. EMSA assay further suggested that FGF7 could interact with the promoter region of CISH and PRKX. This study provides valuable insights into the molecular mechanisms underlying hair cycle. Understanding the interaction between HFSC and DPC, as well as the role of FGF7, could potentially lead to the advancements in regenerative medicine and treatment of hair loss.