The placenta has numerous functions, such as transporting oxygen and nutrients and building the immune tolerance of the fetus. Cell fusion is an essential process for placental development and maturation. In human placental development, mononucleated cytotrophoblast (CTB) cells can fuse to form a multinucleated syncytiotrophoblast (STB), which is the outermost layer of the placenta. Nephrin is a transmembrane protein that belongs to the Ig superfamily. Previous studies have shown that nephrin contributes to the fusion of myoblasts into myotubes in zebrafish and mice, presenting a functional conservation with its Drosophila ortholog sticks and stones. However, whether nephrin is involved in trophoblast syncytialization remains unclear. In this study, we report that nephrin was localized predominantly in the CTB cells and STB of human placenta villi from first trimester to term pregnancy. Using a spontaneous fusion model of primary CTB cells, the expression of nephrin was found to be increased during trophoblast cell fusion. Moreover, the spontaneous syncytialization and the expression of syncytin 2, connexin 43, and human chorionic gonadotropin beta were significantly inhibited by nephrin-specific siRNAs. The above results demonstrate that nephrin plays an important role in trophoblast syncytialization.
Yue Li, Ru Zheng, Rui Wang, Xiaoyin Lu, Cheng Zhu, Hai-Yan Lin, Hongmei Wang, Xiaoguang Yu and Jiejun Fu
Rui Hua, Yao Zhou, Biao Wu, Zhongwei Huang, Yongtong Zhu, Yali Song, Yanhong Yu, Hong Li and Song Quan
Triclosan (TCS) exists ubiquitously in the environment. Several in vitro and in vivo studies have demonstrated that TCS exerts endocrine disruptive effects on reproduction, but data from human populations are limited and conflicting. The objective of our study was to investigate whether high urinary TCS concentration is adversely associated with early reproductive outcomes in women undergoing in vitro fertilization-embryo transfer (IVF-ET). This prospective cohort study was conducted from September 2015 to June 2016, including 156 infertile women undergoing their first IVF-ET cycle. Two spot urine samples were collected prior to oocyte retrieval for TCS detection using solid-phase extraction (SPE) and liquid chromatography coupled with tandem mass spectrometry (LC–MS/MS). Linear regression model and binary logistic regression model were used to evaluate the association between urinary TCS concentrations and IVF outcomes. The intake of aquaculture food may have positive influences on urinary TCS concentrations. After adjustment for age, body mass index (BMI), baseline follicle-stimulating hormone (FSH), antral follicle count (AFC) and smoking status, a significant decrease of top quality embryo formation and implantation rate was observed in patients with urinary TCS concentration greater than or equal to the median level (0.045 μmol/mol Cr). We concluded that TCS exposure may exert negative effects during early stages of human reproduction.
Songcun Wang, Fengrun Sun, Mutian Han, Yinghua Liu, Qinyan Zou, Fuxin Wang, Yu Tao, Dajin Li, Meirong Du, Hong Li and Rui Zhu
There is delicate crosstalk between fetus-derived trophoblasts (Tros) and maternal cells during normal pregnancy. Dysfunctions in interaction are highly linked to some pregnancy complications, such as recurrent spontaneous abortion (RSA), pre-eclampsia and fetal growth restriction. Hyaluronan (HA), the most abundant component of extracellular matrix, has been reported to act as both a pro- and an anti-inflammatory molecule. Previously, we reported that HA promotes the invasion and proliferation of Tros by activating PI3K/Akt and MAPK/ERK1/2 signaling pathways. While lower HA secretion by Tros was observed during miscarriages than that during normal pregnancies, in the present study, we further confirmed that higher secretion of HA by Tros could induce M2 polarization of macrophages at the maternal–fetal interface by interacting with CD44 and activating the downstream PI3K/Akt-STAT-3/STAT-6 signaling pathways. Furthermore, HA could restore the production of IL-10 and other normal pregnancy markers by decidual macrophages (dMφs) from RSA. These findings underline the important roles of HA in regulating the function of dMφs and maintaining a normal pregnancy.
Ru Zheng, Yue Li, Huiying Sun, Xiaoyin Lu, Bao-Fa Sun, Rui Wang, Lina Cui, Cheng Zhu, Hai-Yan Lin and Hongmei Wang
The syncytiotrophoblast (STB) plays a key role in maintaining the function of the placenta during human pregnancy. However, the molecular network that orchestrates STB development remains elusive. The aim of this study was to obtain broad and deep insight into human STB formation via transcriptomics. We adopted RNA sequencing (RNA-Seq) to investigate genes and isoforms involved in forskolin (FSK)-induced fusion of BeWo cells. BeWo cells were treated with 50 μM FSK or dimethyl sulfoxide (DMSO) as a vehicle control for 24 and 48 h, and the mRNAs at 0, 24 and 48 h were sequenced. We detected 28,633 expressed genes and identified 1902 differentially expressed genes (DEGs) after FSK treatment for 24 and 48 h. Among the 1902 DEGs, 461 were increased and 395 were decreased at 24 h, whereas 879 were upregulated and 763 were downregulated at 48 h. When the 856 DEGs identified at 24 h were traced individually at 48 h, they separated into 6 dynamic patterns via a K-means algorithm, and most were enriched in down–even and up–even patterns. Moreover, the gene ontology (GO) terms syncytium formation, cell junction assembly, cell fate commitment, calcium ion transport, regulation of epithelial cell differentiation and cell morphogenesis involved in differentiation were clustered, and the MAPK pathway was most significantly regulated. Analyses of alternative splicing isoforms detected 123,200 isoforms, of which 1376 were differentially expressed. The present deep analysis of the RNA-Seq data of BeWo cell fusion provides important clues for understanding the mechanisms underlying human STB formation.
Rui-Song Ye, Meng Li, Chao-Yun Li, Qi-En Qi, Ting Chen, Xiao Cheng, Song-Bo Wang, Gang Shu, Li-Na Wang, Xiao-Tong Zhu, Qing-Yan Jiang, Qian-Yun Xi and Yong-Liang Zhang
FSH plays an essential role in processes involved in human reproduction, including spermatogenesis and the ovarian cycle. While the transcriptional regulatory mechanisms underlying its synthesis and secretion have been extensively studied, little is known about its posttranscriptional regulation. A bioinformatics analysis from our group indicated that a microRNA (miRNA; miR-361-3p) could regulate FSH secretion by potentially targeting the FSHB subunit. Herein, we sought to confirm these findings by investigating the miR-361-3p-mediated regulation of FSH production in primary pig anterior pituitary cells. Gonadotropin-releasing hormone (GnRH) treatment resulted in an increase in FSHB synthesis at both the mRNA, protein/hormone level, along with a significant decrease in miR-361-3p and its precursor (pre-miR-361) levels in time- and dose-dependent manner. Using the Dual-Luciferase Assay, we confirmed that miR-361-3p directly targets FSHB. Additionally, overexpression of miR-361-3p using mimics significantly decreased the FSHB production at both the mRNA and protein levels, with a reduction in both protein synthesis and secretion. Conversely, both synthesis and secretion were significantly increased following miR-361-3p blockade. To confirm that miR-361-3p targets FSHB, we designed FSH-targeted siRNAs, and co-transfected anterior pituitary cells with both the siRNA and miR-361-3p inhibitors. Our results indicated that the siRNA blocked the miR-361-3p inhibitor-mediated upregulation of FSH, while no significant effect on non-target expression. Taken together, our results demonstrate that miR-361-3p negatively regulates FSH synthesis and secretion by targeting FSHB, which provides more functional evidence that a miRNA is involved in the direct regulation of FSH.