Circ_0003314 Combines with the miR-26b-5p/IL1RAP Axis to Inhibit HTR-8/SVneo Cell Proliferation, Migration, Invasion and Tube Formation and Promote Apoptosis.

Preeclampsia (PE) is a pregnancy-related syndrome that can lead to a variety of pathophysiological processes, such as impaired implantation. The pathogenesis of PE involves circular RNA (circRNA). The study aims to determine the role of a novel circRNA, circ_0003314, in trophoblast cell phenotypes. Circ_0003314, microRNA-26b-5p (miR-26b-5p) and IL-1 receptor accessory protein (IL1RAP) expression were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Cell proliferation was investigated by MTT assay and 5-Ethynyl-2'-deoxyuridine assay. Cell migration and invasion were investigated by transwell assay. Cell apoptotic rate and angiogenesis were investigated by flow cytometry analysis and tube formation assay, respectively. Protein expression was detected by western blotting. The binding relationship between miR-26b-5p and circ_0003314 or IL1RAP was identified using dual-luciferase reporter assay and RNA pull-down assay. Circ_0003314 and IL1RAP expression were significantly increased, while miR-26b-5p was decreased in placental tissues of PE patients. Circ_0003314 overexpression inhibited trophoblast cell proliferation, migration, invasion and angiogenesis and induced cell apoptosis. Additionally, circ_0003314 acted as a sponge for miR-26b-5p, and miR-26b-5p bound to IL1RAP. Introduction of miR-26b-5p or silencing of IL1RAP attenuated the effects of circ_0003314 overexpression on trophoblast cell phenotypes. Further, circ_0003314 induced IL1RAP expression through miR-26b-5p in trophoblast cells. Circ_0003314 regulated trophoblast cell phenotypes by increasing IL1RAP expression through binding to miR-26b-5p.