Function of Heterogeneous Nuclear Ribonucleoprotein U and related MicroRNAs in Human Coronary Artery Endothelial Cells and Endothelial Microparticles

Abstract

The protein heterogeneous nuclear ribonucleoprotein U (hnRNP U) plays an essential role in the development and function of the heart. The hnRNP U protein in human coronary artery endothelial cells (HCAEC) mediates its function by binding microRNAs (miRNAs). Endothelial microparticles (EMP) derived from HCAEC regulate several processes in cardiovascular biology by transferring miRNAs to target cells. In this study, we aimed to explore the function of hnRNP U in HCAEC and EMP.<br /> We found that the hnRNP U protein binds to microRNA-30c (miRNA-30c) and microRNA-24 (miRNA-24) in HCAEC <em>in vitro</em>. Furthermore, the downregulation of hnRNP U in HCAEC decreases the levels of both miRNA-30c and miRNA-24. Downregulation of hnRNP U did not affect the number of EMP released from HCAEC. The miRNA-30c and miRNA-24 expression levels were higher in both EMP and the supernatant when transfected with si-hnRNP U compared to transfection with the siRNA negative control. EMP derived from HCAEC transfected with si-hnRNP U inhibit HCAEC migration and promote proliferation. Furthermore, upregulated miRNA-30c and miRNA-24 expression both inhibit HCAEC motility and promote proliferation <em>in vitro</em>.<br /> HnRNP U protein binds to miRNA-30c and miRNA-24 <em>in vitro</em>. EMP derived from HCAEC cells transfected with si-hnRNP U negatively regulate HCAEC motility and positively promote proliferation.