Upregulation of microRNA‑335 and microRNA‑584 contributes to the pathogenesis of severe preeclampsia through downregulation of endothelial nitric oxide synthase

: The aim of the present study was to identify the differentially expressed microRNAs (miRNAs) in placenta from patients with preeclampsia, and examine their roles in the pathogenesis of preeclampsia in vivo and ex vivo. The placental expression levels of miRNAs were examined in tissue samples harvested from 20 patients with preeclampsia and 20 healthy control individuals. A total of 18 miRNAs were differentially expressed (12 upregulated and six downregulated) among the preeclampsia cases, compared with the controls. By further functional/pathway analysis, two significantly upregulated miRNAs, miR‑335 and miR‑584, were identified. These target endothelial nitric oxide synthase (eNOS), which has been repeatedly reported to be involved in the development of preeclampsia. The present study then verified eNOS as a target gene of miR‑335 and miR‑584 using a luceriferase assay, and confirmed the expression patterns of the two miRNAs and eNOS in preeclampsic and normal placentas. Additionally, to examine the function of miR‑584 and miR‑335 in human placenta, the present study transiently transfected the HTR8/Svneo cell line with miR‑584 and miR‑335 mimics or their inhibitors, and the results of a subsequent Transwell insert invasion assay revealed that miR‑584 and miR‑335 inhibited the migratory ability of the trophoblast cells, and that the effect was 'rescued' by overexpressed eNOS. These data revealed a negative regulatory role of miR‑584 and miR‑335 in the migration of HTR‑8/SVneo cells by targeting eNOS, and identified miR‑584 and miR‑335 as potential novel therapeutic targets in preeclampsia.