High Glucose-Induced Senescent Fibroblasts-Derived Exosomal miR-497 Inhibits Wound Healing by Regulating Endothelial Cellular Autophagy via ATG13.

Fibroblasts play a crucial role in diabetic wound healing, and their senescence is the cause of delayed wound repair. It was reported that fibroblasts can secrete exosomes that can mediate a vital role in diabetic complications. Our purpose is to examine the biological function of high glucose (HG)-induced senescent fibroblasts from the perspective of exosomes and reveal the mechanism at cellular and animal levels. HG-induced senescent fibroblasts were measured by senescence-associated -galactosidase staining and immunofluorescence. Flow cytometry, 5-ethynyl-2'-deoxyuridine (edu), and cell counting kit 8 (CCK-8) assay were applied to detect apoptosis and cell viability. Fibroblasts and endothelial cells were cocultured, and the migration and angiogenesis abilities were detected by scratch, transwell, and tube formation assays. Exosomes were isolated and identified from fibroblasts that were treated differently. Then, the function of exosomes was investigated in cells and mice, including examining the cellular phenotype changes, detecting the autophagy levels, and evaluating the wound healing rate. Furthermore, the potential mechanism by which senescent fibroblast-derived exosomes inhibit wound healing was examined via bioinformatics, real-time quantitive polymerase chain reaction (qPCR), transfection, and dual-luciferase assays. It illustrated that HG-induced senescent fibroblasts exhibited adverse impacts on cellular proliferation, migration, and angiogenesis of endothelial cells via secreting exosomes, and senescent fibroblast-derived exosomes (S-Exos) can delay skin wound defects in mice. Subsequent differential analysis of the GSE153214 and GSE48417 datasets elucidated that miR-497 was the biomarker in the senescent fibroblasts. Interestingly, the miR-497 levels were also elevated in S-Exos. Its overexpression can regulate human umbilical vein endothelial cell function by regulating autophagy via targeting ATG13. Furthermore, experiments also illustrated that miR-497 can delay wound healing and reduce autophagy. Our study demonstrated that exosomes from senescent fibroblasts can impair endothelial cell function and impede diabetic wound healing. The underlying mechanism was that fibroblast-derived exosomal miR-497 can target ATG13 to reduce autophagy, offering insight into new therapy for diabetic complications and other diseases.