Comparative single-cell transcriptomics and preclinical evaluation of human hair follicle and umbilical cord-derived mesenchymal stem cells in skin wound healing

Mesenchymal stem cells (MSCs) are promising candidates for skin repair, but tissue-source heterogeneity may contribute to variable therapeutic outcomes. Human hair follicle-derived mesenchymal stem cells (HFMSCs) are an accessible autologous source, yet their cellular composition and preclinical activity relative to umbilical cord-derived mesenchymal stem cells (UCMSCs) remain incompletely defined. We performed single-cell ribonucleic acid (RNA) sequencing (scRNA-seq) on in vitro-expanded HFMSCs and UCMSCs. Cluster annotation, gene-set scoring, trajectory inference, Single-Cell Regulatory Network Inference and Clustering (SCENIC), and CellChat were used to compare their transcriptional heterogeneity. Preclinical evaluation included trilineage differentiation, scratch assays, and a murine full-thickness wound model, together with histological, immunofluorescence, and quantitative polymerase chain reaction (qPCR) validation. Analysis of 81,910 cells identified five transcriptionally distinct states: STEM-LIKE, mesenchymal progenitor cell (MPC) states 0 and 1 (MPC0 and MPC1), adipogenic-like (ADP), and myofibroblast-like (MYF). UCMSCs were relatively homogeneous and enriched in STEM-LIKE and MPC1 cells. HFMSCs were more heterogeneous and relatively enriched in MPC0, ADP, and MYF cells. HFMSCs also showed stronger transcriptional signatures related to extracellular matrix organization, integrin signaling, and wound repair. HFMSCs closed in vitro scratches faster at early time points. In mice, both MSC treatments improved wound closure relative to control, but overall closure did not differ significantly between HFMSCs and UCMSCs. Histological findings and MPC0/MYF-associated marker signals were consistent with tissue-source-associated differences in matrix organization and hair follicle-associated repair. ADP was too rare for reliable in vivo validation, and none of these associations established subpopulation-specific causality. HFMSCs and UCMSCs have distinct cellular compositions and transcriptional programs that may support different aspects of wound repair. HFMSC-enriched MPC0, ADP, and MYF states were associated with matrix-remodeling and regenerative signatures, whereas UCMSCs were enriched in STEM-LIKE and MPC1 states. These preclinical findings support tissue-source-aware MSC selection and direct functional testing of defined subpopulations before clinical translation.