Abstract 165: Large Extracellular Vesicles-derived MicroRNA-150-5p Is Upregulated In Patients With Aortic Valve Stenosis And Regulates Valvular Endothelial Cell Function

Abstract

Aortic valve stenosis (AVS) is the most common type of valvular disease. Recent evidence indicates that extracellular vesicles (EVs) might play an important role in cardiovascular disease, particularly AVS. However, the contribution of EV-encapsulated microRNAs (miRNAs) in valvular endothelial cells (VECs) and AVS has been poorly investigated. Herein, we identified the differentially expressed miRNAs in large EV-derived aortic valve tissue from patients with AVS and explored the novel role of miR-150-5p in endothelial to mesenchymal transition (EndMT). Our miRNA sequencing revealed several EV-miRNAs (miRNA-150-5p, miR-486-5p, and miR-486-3p) were significantly dysregulated in large EVs from aortic valve tissue in patients with AVS. In silico analysis indicated that miRNA-150-5p is mainly enriched in Wnt, TGF-β, and PI3k/AKT signaling pathways, known to be altered in the pathogenesis of AVS. To elucidate the role of miR-150-5p in AVS, we validated the upregulation of miR-150-5p in AVS patients by RT-qPCR. Importantly, the overexpression of miR-150-5p in VECs treated with TNF-α reduced EndMT, which was quantized by significant expression of EndMT markers (vWF, ACTA1, VIM, and SLUG). To investigate the role of miRNA-150-5p in VEC function, cell migration and tube formation were performed. The data revealed that miR-150-5p regulates VEC function via increased tube formation and reduced cell migration. To further investigate VEC function under the laminar flow, which regulates EC function, we exposed VEC under the flow and found that the expression of miR-150-5p is increased suggesting a protective role in VECs. To study the role of miR-150-5p in intercellular communication, we overexpressed miR-150-5p in donor VECs and incubated them with recipient VECs prior to the labeling of EVs with PKH67. Fluorescent microscopy showed an increased expression of miR-150-5p in recipient VECs. Further, we induced EndMT in VECs after co-incubation with EVs (miR-150-5p overexpression vs. control). Our qPCR-analysis revealed that EV-miR-150-5p rescued the expression of EndMT markers. Our data showed that large EV-associated miR-150-5p was significantly upregulated in AVS and may play a crucial role in cellular crosstalk via regulating function of VEC via EndMT.