Upregulation of circRNA hsa_circ_0008726 in Pre-eclampsia Inhibits Trophoblast Migration, Invasion, and EMT by Regulating miR-345-3p/RYBP Axis

Accumulating evidence shows that impaired spiral artery remodeling, placental dysfunction, and insufficient trophoblast infiltration contribute to the etiology and pathogenesis of pre-eclampsia (PE). circRNAs are a class of endogenous non-coding RNAs implicated in the pathogenesis of many diseases, including PE. This study aims to investigate the role of circRNA hsa_circ_0008726 in regulating the migration and invasion of extravillous trophoblast cells. RNase R assay was performed to confirm that circ_0008726 was a circular transcript. The expression of circ_0008726, RYBP, and miR-345-3p was examined by qRT-PCR. The functional interaction between miR-345-3p and circ_0008726 or RYBP was confirmed using dual-luciferase reporter assay and RNA immunoprecipitation (RIP). Cell migration and invasion ability was analyzed by Transwell assays. Western blot was used for the quantification of RYBP protein level. Circ_0008726 expression was significantly increased in PE placenta tissues as compared with normal placenta tissues. Circ_0008726 was resistant to RNase R digestion and was predominately located in the cytoplasm of HTR-8/SVneo cells. Silencing circ_0008726 promoted cell migration and EMT (epithelial-mesenchymal transition), while circ_0008726 overexpression suppressed these processes. Mechanistically, circ_0008726 sponged miR-345-3p to negatively regulate its expression, and miR-345-3p negatively modulated the expression of RYBP. In PE samples, the expression level of circ_0008726 was negatively correlated with miR-345-3p level, but was positively correlated with RYBP expression. Transfection of miR-345-3p mimic or RYBP knockdown counteracted the effects of circ_0008726 overexpression on cell migration and EMT. Our data demonstrate the upregulation of circ_0008726 in PE placenta, which inhibits the migration, invasion, and EMT of HTR-8/SVneo cells by targeting miR-345-3p/RYBP axis. These data suggest that circ_0008726 could be a potential biomarker and therapeutic target for PE.