Single-Cell Sequencing Reveals That CCL2+ Adipose-Derived Stem Cells Promote Diabetic Wound Healing Through the CCL2-ACKR1 Signaling Axis.

Diabetic wounds, particularly diabetic foot ulcers, represent a significant clinical challenge owing to impaired vascularization, persistent inflammation, and dysfunctional extracellular matrix remodeling. Although adipose-derived stem cells offer therapeutic potential, their heterogeneity and functional impairment within the diabetic microenvironment limit their efficacy. Using single-cell RNA sequencing of human adipose and diabetic wound tissues, we identified a distinct CCL2-expressing ADSC subpopulation that is enriched in obese individuals and exhibits elevated stemness, unique metabolic profiles, and enrichment in pathways related to ECM organization and tissue development. This subpopulation functions as a key communication node, engaging with fibroblasts, macrophages, and endothelial cells through ligand-receptor interactions such as CCL2-ACKR1, TGFB1-TGFBR1, and IL34-CSF1R. Exosomes secreted by these CCL2-positive ADSCs were found to be enriched in CCL2, TGFB1, and IL34. In a diabetic mouse wound model, CCL2-ADSC-derived exosomes significantly accelerated wound closure compared with conventional exosomes, promoting angiogenesis, collagen deposition, and M2-macrophage polarization while reducing pro-inflammatory cytokines. In vitro, these exosomes reversed high-glucose-induced suppression of endothelial cell proliferation, migration, and tube formation. Mechanistically, CCL2 carried by the exosomes activates the PI3K/AKT/mTOR/HIF-1α signaling axis in endothelial cells via ACKR1, an effect abolished by CCL2 neutralization or ACKR1 knockdown. Together, these results demonstrate that the CCL2-positive ADSC subpopulation exerts multi-cellular and multi-target therapeutic actions, and that exosomes derived from this subpopulation offer a potent cell-free strategy to enhance diabetic wound healing by improving vascularization, modulating immune responses, and supporting ECM remodeling.