Exogenous HS Reverses High Glucose-induced Endothelial Progenitor Cells Dysfunction Via Regulating Autophagy

This study aims to determine the effect of exogenous hydrogen sulfide (HS) under high glucose (HG)-induced injury in endothelial progenitor cells (EPCs), and to explore the possible underlying mechanisms. Mononuclear cells were isolated from the peripheral blood of healthy volunteers by density-gradient centrifugation and identified as late EPCs by immunofluorescence and flow cytometry. EPCs were treated with high concentrations of glucose, HS, Baf-A1, 3-MA or rapamycin. Cell proliferation, cell migration and tube formation were measured using cell counting kit-8, Transwell migration and tube formation assays, respectively. Cellular autophagy flux was detected by RFP-GFP-LC3, and Western blotting was used to examine the protein expression levels of LC3B, P62, and phosphorylated endothelial nitric oxide synthase (eNOS) at Thr495 (p-eNOS). Reactive oxygen species (ROS) levels were measured using a DHE probe. HS and rapamycin significantly reversed the inhibitory effects of HG on the proliferation, migration, and tube formation of EPCs. Moreover, HS and rapamycin led to an increase in the number of autophagosomes accompanied by a failure in lysosomal turnover of LC3-II or p62 and p-eNOS expression and ROS production under the HG condition. However, Baf-A1 and 3-MA reversed the effects of HS on cell behavior. Collectively, exogenous HS ameliorated HG-induced EPC dysfunction by promoting autophagic flux and decreasing ROS production by phosphorylating eNOS.