Circular RNA VRK1 facilitates pre-eclampsia progression via sponging miR-221-3P to regulate PTEN/Akt

Pre-eclampsia (PE) is a worldwide pregnancy-related disorder. It is mainly characterized by defect migration and invasion of trophoblast cells. Recently, circular RNAs (circRNAs) have been believed to play a vital role in PE. The expression patterns and the biological functions of circRNAs in PE remain elusive. Here, we performed a circRNA microarray to identify putative PE-related circRNAs. Bioinformatics analyses were used to screen the circRNAs which have potential relationships with pre-eclampsia, and we identified a novel circRNA (circVRK1) that was up-regulated in PE placenta tissues. By using HTR-8/SVneo cells, circVRK1 knockdown significantly enhanced cell migration and invasion abilities, as well as epithelial-mesenchymal transition (EMT). Mechanistically, we found that circVRK1 and PTEN could function as the ceRNAs to miR-221-3p. Overexpression of miR-221-3p promoted cell migration, invasion and EMT via regulating PTEN. The cotransfection of miR-221-3p inhibitor or PTEN reversed the effect from circVRK1 knockdown. Moreover, the circVRK1/miR-221-3p/PTEN axis greatly regulated Akt phosphorylation. In general, circVRK1 suppresses trophoblast cell migration, invasion and EMT, by acting as a ceRNA to miR-221-3p to regulate PTEN, and further inhibit PI3K/Akt activation. The purpose of this paper is to open wide insights to investigate the onset of PE and provide new potential therapeutic targets in PE.