Circ_FURIN promotes trophoblast cell proliferation, migration and invasion in preeclampsia by regulating miR-34a-5p and TFAP2A.

Emerging evidence has shown that circular RNAs (circRNAs) play vital roles in the progression of diverse human diseases. However, the functions of circRNAs in preeclampsia (PE) are largely unknown. In this study, we aimed to explore the functions of the circRNA furin, paired basic amino acid cleaving enzyme (circ_FURIN) in PE development. qRT-PCR and western blot analyses were conducted to determine the levels of circ_FURIN, miR-34a-5p and transcription factor AP-2 alpha (TFAP2A). A Cell Counting Kit-8 (CCK-8) assay and a 5'-ethynyl-2'-deoxyuridine (EdU) incorporation assay were utilized to evaluate the cell proliferation ability. Transwell assays were adopted to estimate cell migration and invasion. A dual-luciferase reporter assay and an RNA pulldown assay were utilized to analyze the relationships among circ_FURIN, miR-34a-5p and TFAP2A. It was found that circ_FURIN was downregulated in PE placental tissues and hypoxia-treated placental trophoblast cells. Overexpression of circ_FURIN promoted trophoblast cell proliferation, migration and invasion under hypoxic conditions. Circ_FURIN functioned as the sponge for miR-34a-5p. MiR-34a-5p overexpression abrogated the effects of circ_FURIN on the proliferation, migration and invasion of trophoblast cells under hypoxic conditions. In addition, TFAP2A was demonstrated to be the target gene of miR-34a-5p. TFAP2A silencing ameliorated the promotive effects of miR-34a-5p inhibition on trophoblast cell proliferation, migration and invasion under hypoxic conditions. In conclusion, circ_FURIN enhanced trophoblast cell proliferation, migration and invasion under hypoxic conditions by elevating TFAP2A expression through sponging miR-34a-5p.