title: MicroRNA-378a-5p targets cyclin G2 to inhibit fusion and differentiation in BeWo cells.
abstract: MicroRNAs are expressed abundantly in the placenta throughout pregnancy. We have previously reported that microRNA (miR)-378a-5p promoted trophoblast migration and invasion. To further understand the role of miR-378a-5p during placental development, we investigated whether it may regulate the differentiation of syncytiotrophoblast (STB). Using a choriocarcinoma cell line, BeWo, we found that miR-378a-5p was down-regulated during forskolin-induced STB differentiation. Transfection of a miR-378a-5p mimic into BeWo cells decreased the formation of multinucleated STB, increased E-cadherin, and decreased the expression level of STB marker genes. On the other hand, transfection of anti-miR-378a-5p resulted in an increase in formation of multinucleated STB and expression of STB marker genes, as well as the loss of E-cadherin. Bioinformatic analysis revealed that miR-378a-5p has four potential binding sites at the 3' untranslated region (UTR) of cyclin G2 (CCNG2). Using luciferase reporter assays, we showed that miR-378a-5p decreased the luciferase activity of reporter constructs that contain CCNG2 3' UTR. In addition, miR-378a-5p decreased, whereas anti-miR-378a-5p increased, CCNG2 mRNA levels. Overexpression of CCNG2 increased the expression of syncytin-1 and fusion index and reversed the inhibitory effects of miR-378a-5p. In contrast, silencing of CCNG2 using siRNA increased E-cadherin and decreased syncytin-1 levels. These findings provide initial evidence that CCNG2 promotes STB differentiation and suggest that miR-378a-5p exerts an inhibitory role in STB differentiation, in part, by down-regulating CCNG2 expression, in the BeWo cell model.
authors.affiliation: Department of Biology, York University, Toronto, Canada.
authors.forename: Uzma
authors.initials: U
authors.lastname: Nadeem
authors.affiliation: Department of Biology, York University, Toronto, Canada.
authors.forename: Gang
authors.initials: G
authors.lastname: Ye
authors.affiliation: Department of Biology, York University, Toronto, Canada.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Salem
authors.affiliation: Department of Biology, York University, Toronto, Canada cpeng@yorku.ca.
authors.forename: Chun
authors.initials: C
authors.lastname: Peng
mesh_terms: D020413:3' Untranslated Regions; D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D045744:Cell Line, Tumor; D002822:Choriocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D056767:Cyclin G2 / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism; D015536:Down-Regulation; D005260:Female; D018507:Gene Expression Regulation, Developmental; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing; D006801:Humans; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D010929:Placentation; D011247:Pregnancy; D012313:RNA / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D020218:Response Elements; D014162:Transfection; D014327:Trophoblasts / Q000378:metabolism* / Q000473:pathology
chemical_list: D020413:3' Untranslated Regions; D014408:Biomarkers, Tumor; C101593:CCNG2 protein, human; D056767:Cyclin G2; C526012:MIRN378 microRNA, human; D035683:MicroRNAs; D009363:Neoplasm Proteins; C039919:RNA, recombinant; D012313:RNA
keywords: cell fusion; cyclin G2; miR-378a-5p; syncytiotrophoblast differentiation