PSAT1 regulates hair follicle growth and stem cell behavior in cashmere goats

The Arbas Cashmere Goat from Inner Mongolia is renowned for its superior-quality cashmere, which is primarily produced by secondary hair follicles (SHFs). Secondary hair follicle stem cells (SHFSCs) are critical regulators of SHF growth and development. However, the specific regulatory mechanisms of phosphoserine aminotransferase 1 (PSAT1) in SHFSCs remain unclear. This study aimed to examine the expression pattern of the PSAT1 gene during SHF cycle transitions in cashmere goats and analyze its effects on SHFSC survival and wound healing.

PSAT1 expression was significantly higher in the anagen phase than in the telogen phase, and was predominantly localized to the bulge region. Functional analyses revealed that elevated PSAT1 expression inhibited SHFSC survival and delayed wound healing; on the other hand, a reduced expression promoted SHFSC survival and accelerated healing. Transcriptomic profiling further demonstrated that PSAT1 expression levels markedly altered the gene expression landscape of SHFSCs. Notably, key signaling pathways essential for hair follicle growth and development, such as Wnt/β-catenin, MAPK, and TGF-β, were significantly affected by PSAT1 modulation.

This study highlights PSAT1 as a critical regulator of SHFSC function in cashmere goats, affecting both cellular survival and regenerative capacity. Through its modulation of multiple signaling pathways, PSAT1 plays a pivotal role in the SHF cycle and may serve as a potential molecular target for improving cashmere fiber production.