Diabetes mellitus is a major cause of blindness and chronic ulcers in the working age population worldwide. Former research have found that differentially expressed circular RNAs (circRNAs) are associated with hyperglycemia (HG)-induced endothelial cell damage. And adipose-derived stem cells (ADSCs)-exosome transplant have more therapeutic effect to enhance wound healing in diabetic mice by delivery circRNA. The current investigation employed high-throughput sequencing to identify circRNAs that are abnormally expressed in endothelial progenitor cells (EPCs) under HG conditions. The regulatory mechanism and predicted targets of one differentially expressed circRNA, circ-Snhg11, were investigated utilizing bioinformatics analyses, luciferase reporter assays, angiogenic differentiation assays, flow cytometric apoptosis analysis, and RT-qPCR. The result show that circ-Snhg11 expression decreased in EPCs under HG conditions and that overexpression of circ-Snhg11 suppressed HG-induced endothelial cell damage and M1-like macrophage polarization. miR-144-3p and HIF-1α were identified as downstream targets of circ-Snhg11, which was further verified by luciferase reporter analysis. miR-144-3p overexpression or HIF-1α inhibition reversed circ-Snhg11 protective effect on HG-induced endothelial cell dysfunction, as evidenced by increased apoptosis, abnormal vascular differentiation, and secretion of inflammatory factors. In addition, miR-144-3p overexpression or inhibition of HIF-1α reversed protective effect regarding circ-Snhg11 on M2-like macrophage polarization under HG conditions. These findings suggest that circ-Snhg11 promotes HIF-1α expression through miR-144-3p sponging. Our data demonstrate that circ-Snhg11 overexpression exosome from ADSCs suppresses HG-induced endothelial cell damage and induces M2-like macrophage polarization via the miR-144-3p/HIF-1α axis.

Diabetes mellitus is a major cause of blindness and chronic ulcers in the working‐age population worldwide. Wound healing is deeply dependent on neovascularization to restore blood flow. Former research has found that differentially expressed circular RNAs (circRNAs) are associated with hyperglycaemia‐induced endothelial cell damage, and hypoxia‐pretreated adipose‐derived stem cells (ADSCs)‐extracellular vesicle (HEV) transplants have a more therapeutic effect to enhance wound healing in diabetic mice by delivery circRNA. The current investigation employed high‐throughput sequencing to identify circRNAs that are abnormally expressed between EV and HEV. The regulatory mechanism and predicted targets of one differentially expressed circRNA, circ‐IGF1R, were investigated utilizing bioinformatics analyses, luciferase reporter assays, angiogenic differentiation assays, flow cytometric apoptosis analysis and RT‐qPCR. Circ‐IGF1R expression increased in HEV, and downregulation of circ‐IGF1R suppressed and reversed the promotion effect of HEV on angiogenesis in ulcerated tissue. Bioinformatics analyses and luciferase reporter assays confirmed that miR‐503‐5p was the downstream target of circ‐IGF1R, and inhibiting miR‐503‐5p restored the promotion effect of HEV on angiogenesis after circ‐IGF1R silence. The study also found that miR‐503‐5p can interact with 3'‐UTR of both HK2 and VEGFA. Overexpression of HK2 or VEGFA restored the promotion effect of HExo on angiogenesis after circ‐IGF1R silence. Overexpression miR‐503‐5p or silence HK2/VEGFA reversed the protective effect of circ‐IGF1R to MLMECs angiogenic differentiation. Overexpression of circ‐IGF1R increased the protective effect of HEV on the promotion of wound healing in mice with diabetes. Circ‐IGF1R promotes HIF‐1α expression through miR‐503‐5p sponging. Our data demonstrate that circ‐IGF1R overexpression EVs from ADSCs suppress high glucose‐induced endothelial cell damage by regulating miR‐503‐5p/HK2/VEGFA axis.