Endothelial dysfunction is a marked feature of Kawasaki disease during convalescence, but its pathogenesis is currently unclear. Circulating microRNAs (miRNAs) are associated with the progression of Kawasaki disease. However, the role and mechanism of circulating miRNAs in endothelial dysfunction are largely unknown. Kawasaki disease patients were found to have a unique circulating miRNA profile, including upregulation of miRNA-210-3p, miR-184 and miR-19a-3p, compared to non-Kawasaki disease febrile controls. This study aimed to investigate the effects of these three miRNAs on endothelial function.

Overexpression of miRNAs in human umbilical vein endothelial cells was done by transfection of miRNA mimics. The tube formation assay was used to evaluate the function of human umbilical vein endothelial cells. The potential binding sites of miRNAs on 3’untranslated regions were predicted by using TargetScan database and validated by dual luciferase reporter assay. The protein expression of AGO2, PTEN and VEGF in human umbilical vein endothelial cells was detected by Western blot. Overexpression of AGO2 in human umbilical vein endothelial cells was done by transfection of AGO2 expression plasmids.

Overexpression of miRNA-184 and miRNA-19a-3p, but not miR-210-3p, impaired the function of human umbilical vein endothelial cells. Mechanistically, miR-184 and miR-19a-3p could target the 3’untranslated regions of AGO2 mRNA to downregulate its expression and subsequently impede the AGO2/PTEN/VEGF axis. To be noted, the rescue of the expression of AGO2 remarkably recovered the function that was impaired by overexpression of miRNA-184 and miRNA-19a-3p.

This study suggested that miR-184 and miR-19a-3p could target AGO2/PTEN/VEGF axis to induce endothelial dysfunction in Kawasaki disease.