CXCL12 Drives Reversible Fibroimmune Remodeling in Androgenetic Alopecia Revealed by Single-Cell RNA Sequencing.

Androgenetic alopecia (AGA) is a common form of hair loss characterized by androgen-driven tissue remodeling, including progressive follicular miniaturization and dermal fibrosis, which is accompanied by low-grade immune activation. However, the molecular mechanisms underlying this fibroimmune dysfunction remain poorly understood. Dermal fibroblasts (DFs) have been suggested as androgen-responsive stromal cells and a potential source of CXCL12, a chemokine implicated in fibroimmune pathology, but their precise role in AGA has not been fully established. In this study, we performed single-cell transcriptomic profiling of a testosterone-induced mouse model of AGA, with or without treatment of CXCL12-neutralizing antibody, to elucidate the pathological role of CXCL12 in mediating stromal-immune interactions. Our analysis suggested that DFs are the primary androgen-responsive population driving CXCL12 expression. Autocrine CXCL12-ACKR3 signaling in DFs activated TGF-β pathways and promoted fibrotic extracellular matrix deposition. In parallel, paracrine CXCL12-CXCR4 signaling reprogrammed Sox2+Twist1+ dermal papilla cells (DPCs) and promoted the accumulation of pro-fibrotic Trem2+ macrophages, contributing to impaired hair follicle regeneration. Notably, CXCL12 blockade attenuated these stromal and immune alterations, restored the regenerative capacity of DPCs, reduced pro-fibrotic macrophage infiltration, and promoted hair regrowth. Together, these findings identify CXCL12 as a central mediator of androgen-induced fibroimmune remodeling and highlight its potential as a therapeutic target in AGA.