Exosomes From Endothelial Progenitor Cells Facilitate Vascular Endothelial Cell Repair Through MiR-21-5p

Background and Objective: Endovascular therapies are widely used techniques to treat patients with cerebrovascular diseases.However,even with drug-eluting stents,there is still a risk of restenosis.Intervention-associated vascular endothelial cell injury is the key element in the initiation and progression.Thus,timely promotion of endothelial cell repair is crucial to prevent progression of restenosis.Our previous studies indicated that administration of exosomes from endothelial progenitor cells(EPCs)facilitated vascular repair in rat models of balloon injury.However,the underling molecular mechanism remains unclear.Here,we set out to interrogate key miRNA content within EPC-derived exosomes responsible for the activation of endothelial cells(ECs)repair.Methods: Endothelial progenitor cells derived from human umbilical cord blood were isolated and induced,then cells were identified by flow cytometry analysis of detection of cell surface marker expression and endothelial cell function.The exosomes in the endothelial progenitor cell culture medium were extracted by ultrafiltration combined with ultracentrifugation.Exosomes were identified by Nanoparticle tracking analysis(NTA),transmission electron microscopy(TEM),and Western Blotting.The efficacy of EPCs derived exosomes in reendothelialization was examined by Evans blue dye and histological examinations in the balloon-induced carotid artery endothelial injury model of rats.The effects of EPCs exosomes on human vascular endothelial cells(HUVECs)were also studied by the evaluation of growth rates,migratory ability and tube-formation activity.To dissect the underlying mechanisms,RNA-sequencing assays were performed to determine miRNA abundancy in exosomes and mRNA profiles in exosome-treated HUVECs.Meanwhile,in vitro loss of function assays identified an exosomal miRNA and its target gene in ECs that were engaged in the EPCs exosome-induced ECs repairment.Results: Administration of EPC-derived exosomes enhanced the reendothelialization in the early phase after endothelial damage in the rat carotid artery.The proliferation rate,migratory and tube-forming ability of HUVECs were enhanced by the uptake of exogenous EPCs exosomes.Integrative analyses of miRNA-mRNA interactions revealed that miR-21-5p was highly enriched in EPCs exosomes and specifically suppressed the expression of an angiogenesis inhibitor THBS1 in the recipient vascular endothelial cells.The following functional studies demonstrated a fundamental role of miR-21-5p in the pro-angiogenic activitie of EPCs derived exosomes.Conclusions: The present work highlights an event critical for the regulation of EC behavior by EPCs exosomes,through which EPCs exosomes delivers miR-21-5p that inhibiters THBS1 expression to promote endothelial cell repair.