MicroRNA-155 inhibits migration of trophoblast cells and contributes to the pathogenesis of severe preeclampsia by regulating endothelial nitric oxide synthase

The aim of the present study was to characterize the role of microRNA (miR)-155 in the pathogenesis of severe preeclampsia (PE). A total of 19 severe preeclampsic and 22 normal placentas were collected to measure miR-155 and endothelial nitric oxide synthase (eNOS) expression using quantitative (q)PCR and western blot analysis. The results demonstrated a significant increase in the levels of miR-155 and decreased eNOS expression in the severe preeclampsic placentas, as compared with the normal controls. In order to examine the function of miR-155 in the human placenta, the HTR8/Svneo cell line was transiently transfected with an miR-155 mimic or its inhibitor, anti-miR-155. It was confirmed that miR-155 may suppress the expression of eNOS in HTR-8/SVneo cells. Furthermore, a transwell insert invasion assay demonstrated that miR-155 inhibited cell invasion in trophoblast cells, and the effect was rescued by over expression of eNOS. The present study revealed that miR-155 has a negative regulatory role in the migratory behavior of HTR-8/SVneo cells via modulating eNOS.