The ferroptosis-associated gene TIMP1 facilitates skin scar formation through the interaction with CST3 in fibroblasts.

Skin scar formation is a critical pathological process in wound healing, but its underlying regulatory mechanisms remain incompletely elucidated. By integrating analyses of Bulk-RNA seq and single-cell RNA sequencing (scRNA-seq) data, we identified that ferroptosis-related biological processes potentially play a key role in skin scar formation. Further mechanistic studies demonstrated that in human dermal fibroblast cells, the ferroptosis regulator TIMP metallopeptidase inhibitor 1 (TIMP1) significantly promotes fibroblast differentiation toward a mature phenotype through interactions with cystatin C (CST3), characterized by upregulated expression of myofibroblast differentiation markers such as α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF), along with enhanced cell proliferation and migration abilities. Cell communication analysis from single-cell data and in vitro co-culture experiments further confirmed that TIMP1-high-expressing fibroblasts drive macrophages to polarize toward a pro-repair M2 phenotype through CCL5-GPR75 signal axis. Subsequently, M2 macrophages reciprocally secrete cytokines to further enhance fibroblast functional activation, thereby forming a bidirectional "fibroblast-macrophage" regulatory network with positive feedback effects that contribute to a profibrotic immune microenvironment. This study highlights the central role of ferroptosis-associated TIMP1 in skin scar formation, and the cell interaction network regulated by TIMP1 offers novel molecular targets and combined intervention strategies for scar prevention and treatment.