Overexpression of HIF2α Enhances the Angiogenesis-Promoting Effect of hUC-MSC-Derived Extracellular Vesicles by Stimulating miR-146a.

Objective: This study aimed to explore whether excessive HIF2α can amplify the impact of human Umbilical Cord Mesenchymal Stem Cell-derived Extracellular Vesicles (hUC-MSC- EVs) on endothelial cells.

Methods: In this study, we created HIF2α-overexpressing hUC-MSC-EVs and compared their pro-angiogenic effects with control EVs on Human Umbilical Vein Endothelial Cells (HUVECs). MTT assay and Edu staining were used to detect the viability and proliferation ability of HUVECs, and Transwell and Tube Formation Assays were used to detect cell migration and tube formation ability. qPCR assay was used to detect the expression of cellular angiogenic markers. Subsequently, miRNAs that might be regulated by HIF2α were predicted by bioinformatics analysis, and qPCR was used to detect the relative expression of miRNAs in HUVECs treated with hUC-MSC- EV, which over-expresses HIF2α. Subsequently, miR-146a inhibitors were used to investigate the role of miR-146a in mediating the pro-angiogenic effect of HIF2α on HUVECs by detecting cell viability, proliferation, migration, tube-forming ability, and expression of angiogenic markers. Finally, AKT/ERK phosphorylation and Spred1 expression were detected using Western blotting.

Results: Our findings have indicated that overexpression of HIF2α significantly enhances the ability of hUC-MSC-EVs to stimulate proliferation, migration, and tube formation in HUVECs, as demonstrated by MTT/Edu staining, Transwell assay, and tube formation assay results, respectively. Mechanistically, excessive HIF2α has been found to induce the expression of miR-146a in HUVECs and the overexpression of a miR-146a inhibitor to negate the influence of excessive HIF2α on hUC-MSC-EV-induced activity in HUVECs.

Conclusion: The overexpression of HIF2α is an effective strategy for enhancing the pro-angiogenic function of hUC-MSC-EVs.