Hypoxic ADSC-derived exosomes enhance wound healing in diabetic mice via delivery of circ-Snhg11 and induction of M2-like macrophage polarization.

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.