Regulatory Effects of FGF9 on Dermal Papilla Cell Proliferation in Small-Tailed Han Sheep

Fibroblast growth factor 9 ( ) is crucial for the growth and development of hair follicles (HFs); however, its role in sheep wool growth is unknown. Here, we clarified the role of in HF growth in the small-tailed Han sheep by quantifying expression in skin tissue sections collected at different periods. Moreover, we evaluated the effects of protein supplementation on hair shaft growth in vitro and knockdown on cultured dermal papilla cells (DPCs). The relationship between and the Wnt/β-catenin signaling pathway was examined, and the underlying mechanisms of -mediated DPC proliferation were investigated. The results show that expression varies throughout the HF cycle and participates in wool growth. The proliferation rate and cell cycle of -treated DPCs substantially increase compared to that of the control group, and the mRNA and protein expression of , a Wnt/β-catenin signaling pathway marker gene, is considerably lower than that in the control group. The opposite occurs in -knockdown DPCs. Moreover, other signaling pathways are enriched in the -treated group. In conclusion, accelerates the proliferation and cell cycle of DPCs and may regulate HF growth and development through the Wnt/β-catenin signaling pathway.