Wingless (Wnt)-3A induces trophoblast migration and matrix metalloproteinase-2 secretion through canonical Wnt signaling and protein kinase B/AKT activation

NOTUM-MEDIATED WNT SILENCING DRIVES EXTRAVILLOUS TROPHOBLAST CELL LINEAGE DEVELOPMENT

Trophoblast stem (TS) cells have the unique capacity to differentiate into specialized cell types, including extravillous trophoblast (EVT) cells. EVT cells invade into and transform the uterus where they act to remodel the vasculature facilitating the redirection of maternal nutrients to the developing fetus. Disruptions in EVT cell development and function are at the core of pregnancy-related disease. WNT-activated signal transduction is a conserved regulator of morphogenesis of many organ systems, including the placenta. In human TS cells, activation of canonical WNT signaling is critical for maintenance of the TS cell stem state and its downregulation accompanies EVT cell differentiation. We show that aberrant WNT signaling undermines EVT cell differentiation. Notum, palmitoleoyl-protein carboxylesterase (NOTUM), a negative regulator of canonical WNT signaling, was prominently expressed in first trimester EVT cells developing in situ and upregulated in EVT cells derived from human TS cells. Furthermore, NOTUM was required for human TS cell differentiation to EVT cells. Activation of NOTUM in EVT cells is driven, at least in part, by endothelial PAS domain 1 (also called hypoxia-inducible factor 2 alpha). Collectively, our findings indicate that canonical WNT signaling is essential for maintenance of human trophoblast cell stemness and prevention of human TS cell differentiation. Downregulation of canonical WNT signaling via the actions of NOTUM is required for EVT cell differentiation.

WNT and NOTCH signaling in human trophoblast development and differentiation

Correct development of the human placenta and its differentiated epithelial cells, syncytial trophoblasts (STBs) and extravillous trophoblasts (EVTs), is crucial for a successful pregnancy outcome. STBs develop by cell fusion of mononuclear cytotrophoblasts (CTBs) in placental floating villi, whereas migratory EVTs originate from specialized villi anchoring to the maternal decidua. Defects in trophoblast differentiation have been associated with severe pregnancy disorders such as early-onset preeclampsia and fetal growth restriction. However, the evolutionary pathways underlying normal and adverse placentation are poorly understood. Herein, we discuss Wingless (WNT) and NOTCH signaling, two pathways that play pivotal roles in human placenta and trophoblast development. Whereas WNT is necessary for expansion of trophoblast progenitors and stem cells, NOTCH1 is required for proliferation and survival of EVT precursors. Differentiation of the latter is orchestrated by a switch in NOTCH receptor expression as well as by changes in WNT ligands and their downstream effectors.

New-onset postpartum preeclampsia: epigenetic mechanism and prediction

OBJECTIVE

Placental cytosine (CpG) methylation was measured to predict new-onset postpartum preeclampsia (NOPP) and interrogate its molecular pathogenesis.

METHODS

NOPP was defined as patients with a new diagnosis of postpartum preeclampsia developing ≥48 h to ≤6 weeks after delivery with no prior hypertensive disorders. Placental tissue was obtained from 12 NOPP cases and 12 normotensive controls. Genome-wide individual cytosine (CpG) methylation level was measured with the Infinium MethylationEPIC BeadChip array. Significant differential methylation (NOPP vs. controls) for individual CpG loci was defined as false discovery rate (FDR) p value <.05. Gene functional enrichment using Qiagen's ingenuity pathway analysis (IPA) was performed to help elucidate the molecular pathogenesis of NOPP. A logistic regression model for NOPP prediction based on the methylation level in a combination of CpG loci was generated. The area under the receiver operating characteristic curves (AUC [95% CI]) sensitivity, and specificity for NOPP prediction based on the CpG methylation level was calculated for each locus.

RESULTS

There were 537 (in 540 separate genes) significantly (FDR p<.05 with a ≥ 2.0-fold methylation difference) differentially methylated CpG loci between the groups. A total of 143 individual CpG markers had excellent individual predictive accuracy for NOPP prediction (AUC ≥0.80), of which 14 markers had outstanding accuracy (AUC ≥0.90). A logistic regression model based on five CpG markers yielded an AUC (95% CI)=0.99 (0.95-0.99) with sensitivity 95% and specificity 93% for NOPP prediction. IPA revealed dysregulation of critical pathways (e.g., angiogenesis, chronic inflammation, and epithelial-mesenchymal transition) known to be linked to classic preeclampsia, in addition to other previously undescribed genes/pathways.

CONCLUSIONS

There was significant placental epigenetic dysregulation in NOPP. NOPP shared both common and unique molecular pathways with classic preeclampsia. Finally, we have identified novel potential biomarkers for the early post-partum prediction of NOPP.

Placental Angiogenesis in Mammals: A Review of the Regulatory Effects of Signaling Pathways and Functional Nutrients

Normal placental development and proper angiogenesis are essential for fetal growth during pregnancy. Angiogenesis involves the regulatory action of many angiogenic factors and a series of signal transduction processes inside and outside the cell. The obstruction of placental angiogenesis causes fetal growth restriction and serious pregnancy complications, even leading to fetal loss and pregnancy cessation. In this review, the effects of placental angiogenesis on fetal development are described, and several signaling pathways related to placental angiogenesis and their key regulatory mediators are summarized. These factors, which include vascular endothelial growth factor (VEGF)-VEGF receptor, delta-like ligand 4 (DLL-4)-Notch, Wnt, and Hedgehog, may affect the placental angiogenesis process. Moreover, the degree of vascularization depends on cell proliferation, migration, and differentiation, which is affected by the synthesis and secretion of metabolites or intermediates and mutual coordination or inhibition in these pathways. Furthermore, we discuss recent advances regarding the role of functional nutrients (including amino acids and fatty acids) in regulating placental angiogenesis. Understanding the specific mechanism of placental angiogenesis and its influence on fetal development may facilitate the establishment of new therapeutic strategies for the treatment of preterm birth, pre-eclampsia, or intrauterine growth restriction, and provide a theoretical basis for formulating nutritional regulation strategies during pregnancy.

Long intergenic noncoding RNA 00473 promoting migration and invasion of trophoblastic cell line HTR-8/SVneo via regulating miR-424-5p-mediated wnt3a/β-catenin signaling pathway

BACKGROUND

Preeclampsia (PE) is a serious obstetric complication. Recent studies point out that the functions of long intergenic noncoding RNA 00473 (linc00473), miR-424-5p, and Wnt/β-catenin signaling pathway were involved in the invasion and migration of extravillous trophoblast. Here, we investigated the role and mechanism of linc00473 in HTR-8/SVneo trophoblastic cell line and its role in PE.

METHOD

The expression levels of linc00473 and miR-424-5p in placental tissues and the transfection efficiency of miR-424-5p were detected by quantitative real-time polymerase chain reaction (qRT-PCR). HTR-8/SVneo cell invasion and proliferation were determined by transwell and Cell Counting Kit-8 (CCK-8) assays. The protein expressions of wnt3a, p-GSK3β, GSK3β, active β-catenin, and total β-catenin were detected by Western blot. The apoptosis and migration of HTR-8/SVneo cells were detected by flow cytometry and wound healing assays. The targeting relationships between linc00473, miR-424-5p, and wnt3a were predicted by ENCORI database and TargetScan V7.2 and were determined using dual-luciferase reporter assay.

RESULTS

The expression level of linc00473 was low and miR-424-5p was high in placenta of PE patients. Linc00473 can target miR-424-5p, while miR-424-5p target wnt3a. High expression of linc00473 and wnt3a promoted cell proliferation, migration, invasion, and inhibited cell apoptosis. However, miR-424-5p mimic inhibited HTR-8/SVneo cells proliferation, migration, invasion, while promoted cell apoptosis, partially reversed the effect of linc00473, while wnt3a overexpression partially counteracted the effect of miR-424-5p mimic.

CONCLUSION

Linc00473 mediates the regulation of Wnt/β-catenin signaling pathway by miR-424-5p to affect the invasion and migration ability of trophoblastic cell line HTR-8/SVneo. It indicated that linc00473 is involved in PE and could be a therapeutic target.

Long noncoding RNA expression profiling identifies MIR210HG as a novel molecule in severe preeclampsia

OBJECTIVE

Preeclampsia (PE) is a potentially fatal pregnancy-specific complication. Nevertheless, the pathogenesis of PE remains indistinct. Recently, increasing studies emphasized that long noncoding RNAs (lncRNAs) functions as imperative regulators in PE. The aim of this study was to compare the lncRNAs transcript profile of placentae in early onset severe preeclampsia (EOSP) with lncRNAs in normal pregnancy (NP) and to evaluate the role of lncRNA MIR210HG (microRNA 210 host gene) in the PE pathogenesis.

METHODS

Using RNA sequencing, we compared transcriptome profiles of placentae in EOSP (n = 3) and NP (n = 3). Bioinformatic tools were used to predict the function of differentially expressed genes while qRT-PCR was used to verify RNA sequencing data. The role of MIR210HG in HTR8/SVneo migration and invasion were analyzed by in vitro MIR210HG gene overexpression.

RESULTS

Our results showed that 527 lncRNAs and 600 mRNAs were differentially expressed in placental samples of EOSP, and the analysis identified 63 key EOSP related genes. As indicated by bioinformatics analyses, lncRNA MIR210HG was a potential pathogenic marker of PE. LncRNA-MIR210HG expression was upregulated in placental samples of PE and enriched in the canonical Wnt signalling pathway. MiR210HG overexpression inhibited HTR8/SVneo cell migration and invasion in vitro. Additionally, miR210HG upregulated dickkopf-1 expression via the sponging of microRNA-520a-3p (miR-520a-3p), thus repressing trophoblast migration and invasion.

CONCLUSION

Our study showed that MiR210HG is a novel upregulated lncRNA in the placentas of PE and MiR210HG regulates the migration and invasive potential of HTR-8/SVneo cell by targeting the miR-520a-3p/Dickkopf-1 axis.

Oxidative stress-induced downregulation of glycogen synthase kinase 3 beta in fetal membranes promotes cellular senescence†

OBJECTIVE

Oxidative stress (OS)-induced stress signaler p38 mitogen-activated protein kinase (p38MAPK) activation and fetal membrane senescence are associated with parturition. This study determined changes in glycogen synthase kinase 3 beta (GSK3β) and its regulation by p38MAPK in effecting senescence to further delineate the molecular mechanism involved in senescence.

METHODS

Primary human amnion epithelial cells and amnion mesenchymal cells were treated with cigarette smoke extract (CSE, OS inducer). Expression of total and phosphorylated GSK3β and p38MAPK, and that of GSK3β's downstream targets: beta-catenin (β-Cat) and nuclear factor erythroid 2-related factor 2 (Nrf2) (western blot analysis), cell cycle regulation and senescence (flow cytometry) were determined. The specificity of GSK3β and p38MAPK's mechanistic role was tested by co-treating cells with their respective inhibitors, CHIR99021 and SB203580. Exosomal secretion of β-Cat from OS-induced cells was confirmed by immunofluorescence confocal microscopy and western blot.

RESULTS

OS induced by CSE resulted in phosphorylation of GSK3β (inactivation) and p38MAPK (activation) that was associated with cell cycle arrest and senescence. Inhibitors to GSK3β and p38MAPK verified their roles. Glycogen synthase kinase 3 beta inactivation was associated with nuclear translocation of antioxidant Nrf2 and exosomal secretion of β-Cat.

CONCLUSIONS

OS-induced P-p38MAPK activation is associated with functional downregulation of GSK3β and arrest of cell cycle progression and senescence of amnion cells. Lack of nuclear translocation of β-Cat and its excretion via exosomes further supports the postulation that GSK3β down-regulation by p38MAPK may stop cell proliferation preceding cell senescence. A better understanding of molecular mechanisms of senescence will help develop therapeutic strategies to prevent preterm birth.

Systematic Identification of Hub Genes in Placenta Accreta Spectrum Based on Integrated Transcriptomic and Proteomic Analysis

Placenta accreta spectrum (PAS) is a pathological condition of the placenta with abnormal adhesion or invasion of the placental villi to the uterine wall, which is associated with a variety of adverse maternal and fetal outcomes. Although some PAS-related molecules have been reported, the underlying regulatory mechanism is still unclear. Compared with the study of single gene or pathway, omics study, using advanced sequencing technology and bioinformatics methods, can increase our systematic understanding of diseases. In this study, placenta tissues from 5 patients with PAS and 5 healthy pregnant women were collected for transcriptomic and proteomic sequencing and integrated analysis. A total of 728 messenger RNAs and 439 proteins were found to be significantly different between PAS group and non-PAS group, in which 23 hub genes were differentially expressed in both transcriptome and proteome. Functional enrichment analysis showed that the differentially expressed genes were mainly related to cell proliferation, migration and vascular development. Totally 18 long non-coding RNA were found that might regulate the expression of hub genes. Many kinds of single nucleotide polymorphism, alternative splicing and gene fusion of hub genes were detected. This is the first time to systematically explore the hub genes and gene structure variations of PAS through integrated omics analysis, which provided a genetic basis for further in-depth study on the underlying regulatory mechanism of PAS.

Gasotransmitters in pregnancy: from conception to uterine involution

Gasotransmitters are endogenous small gaseous messengers exemplified by nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S or sulfide). Gasotransmitters are implicated in myriad physiologic functions including many aspects of reproduction. Our objective was to comprehensively review basic mechanisms and functions of gasotransmitters during pregnancy from conception to uterine involution and highlight future research opportunities. We searched PubMed and Web of Science databases using combinations of keywords nitric oxide, carbon monoxide, sulfide, placenta, uterus, labor, and pregnancy. We included English language publications on human and animal studies from any date through August 2018 and retained basic and translational articles with relevant original findings. All gasotransmitters activate cGMP signaling. NO and sulfide also covalently modify target protein cysteines. Protein kinases and ion channels transduce gasotransmitter signals, and co-expressed gasotransmitters can be synergistic or antagonistic depending on cell type. Gasotransmitters influence tubal transit, placentation, cervical remodeling, and myometrial contractility. NO, CO, and sulfide dilate resistance vessels, suppress inflammation, and relax myometrium to promote uterine quiescence and normal placentation. Cervical remodeling and rupture of fetal membranes coincide with enhanced oxidation and altered gasotransmitter metabolism. Mechanisms mediating cellular and organismal changes in pregnancy due to gasotransmitters are largely unknown. Altered gasotransmitter signaling has been reported for preeclampsia, intrauterine growth restriction, premature rupture of membranes, and preterm labor. However, in most cases specific molecular changes are not yet characterized. Nonclassical signaling pathways and the crosstalk among gasotransmitters are emerging investigation topics.

ERp29 affects the migratory and invasive ability of human extravillous trophoblast HTR-8/SVneo cells via modulating the epithelial-mesenchymal transition

Dysfunction of trophoblast metastasis into the endometrium is the main cause of pre-eclampsia (PE); however, the factors affecting this process are still unclear. In this study, we found that endoplasmic reticulum protein 29 (ERp29), one molecular chaperone of the endoplasmic reticulum, was aberrantly upregulated in the placenta of pre-eclamptic patients compared with healthy controls. Then, an in vitro study using human extravillous trophoblast HTR-8/SVneo cells showed that ERp29 upregulation could inhibit the migratory and invasive ability of HTR-8/SVneo cells, while ERp29 downregulation had the opposite effect. Mechanical experiments confirmed that ERp29 blocked trophoblast metastasis via inhibiting the process of epithelial-mesenchymal transition and affecting the Wnt/β-catenin signaling pathway. In conclusion, this study revealed the important role of ERp29 in trophoblast metastasis and improved the mechanical understanding of PE occurrence.

Extravillous trophoblast invasion accelerated by WNT3A, 5A, and 10B via CD44

INTRODUCTION

Appropriate extravillous trophoblast (EVT) invasion is essential for successful pregnancy. Previously, we showed that EVTs express CD44, which accelerated EVT invasion. However, its regulation mechanism via CD44 remains unknown. Our hypothesis was that WNT signaling enhanced EVT invasion via CD44. To test this hypothesis, we investigated the effects of WNT ligands on CD44 expression and EVT invasion using EVT cell lines and isolated primary EVTs.

METHODS

We used EVT cell lines (HTR8/SVneo and HChEpC1b) and isolated primary EVTs, extracted from first-trimester trophoblasts. The cells were supplemented with WNT3A, 5A, and 10B. We examined cell invasion and the expressions of CD44 and matrix metalloproteinase (MMP) 9. Next, to clarify the pathway of WNT10B in EVTs, we knock-downed WNT10B using siRNA and activated or inhibited the WNT canonical pathway using an activator (lithium chloride) or inhibitor (FH535, XAV939) with WNT10B addition.

RESULTS

WNT3A, 5A, and 10B accelerated the invasion in the EVT lines and isolated primary EVTs. The expressions of CD44 and MMP9 were also upregulated by WNT ligands. WNT10B knockdown significantly inhibited EVT invasion concomitantly with CD44 expression. The WNT canonical pathway activator upregulated CD44 expression and its inhibitor downregulated it with WNT10B addition.

CONCLUSIONS

The present study is the first to show the possibility that WNT3A, WNT5A, and WNT10B exist upstream of CD44 in EVTs. Among them, WNT10B may be a novel accelerator of EVT invasion. WNT signaling mediated by multiple WNT ligands may contribute to EVT invasion.

Wnt3a protein overexpression predicts worse overall survival in laryngeal squamous cell carcinoma

As a classical ligand in the canonical Wnt/β-catenin signaling pathway, the role of Wnt3a in laryngeal squamous cell carcinoma (LSCC) remains unclear. Therefore, the expression pattern of the Wnt3a protein in 222 primary LSCC, and 19 corresponding adjacent non-carcinoma specimens, was detected by immunohistochemistry and further correlated with clinicopathological parameters. The results showed that LSCC tissue expressed higher levels of the Wnt3a protein when compared to the corresponding adjacent non-cancerous tissues. High expression of Wnt3a was closely related to histological grade (P = 0.031), clinical stage (I+II / III+IV; P = 0.004), and lymph node metastasis (P = 0.03). Kaplan-Meier analysis evidenced that a worse overall survival (OS) was correlated to the group with high Wnt3a expression (P = 0.003). When stratified survival analyses were performed, patients with lymph node metastasis/advanced clinical stages and high Wnt3a expression had worse OS rates than patients with other features (P < 0.001). Finally, multivariate analysis showed that Wnt3a expression was an independent prognosis factor for LSCC patients. The current findings suggest that Wnt3a is tightly related to the LSCC progression and could serve as a valuable clinic biomarker for LSCC patients.

SIRT1 negatively regulates invasive and angiogenic activities of the extravillous trophoblast

PROBLEM

Dysregulation of extravillous trophoblast (EVT) invasion leads to pregnancy complications, such as pre-eclampsia, fetal growth restriction, and placenta accreta. The aim of this study was to explore the role of SIRT1 in EVT invasion and its underlying mechanism.

METHOD OF STUDY

SIRT1-specific siRNA was transfected into Swan 71 cells, an immortalized first trimester trophoblast cell line. The Boyden chamber invasion assay, the scratch wound healing assay, and cell proliferation assay were performed. The expression levels of epithelial-to-mesenchymal transition (EMT) markers, matrix metalloproteinase-2 (MMP-2), MMP-9, p-Akt, Akt, p-p38MAPK, p38MAPK, p-ERK, ERK, p-JNK, JNK, Fas, and Fas ligand (FasL) were examined by western blot. Tube formation assay was conducted by using Matrigel.

RESULTS

SIRT1 knockdown by siRNA significantly enhanced invasion and migration as well as the expression of MMP-2, MMP-9, and EMT markers in Swan 71 cells, but reduced proliferation. The effects of SIRT1 knockdown on invasion, migration, proliferation, and endothelial-like tube formation in Swan 71 cells were reversely regulated by blockade of Akt and p38MAPK signaling. In addition, SIRT1 knockdown markedly promoted colocalization of Swan 71 cells to human umbilical vein endothelial cell (HUVEC) networks and induced reduction in Fas and enhancement of FasL. Conditioned media of SIRT1 knockdown-Swan 71 cells caused reduction in cell proliferation and augmentation of cytotoxicity along with increased Fas expression in HUVECs.

CONCLUSION

Our results suggest that SIRT1 may be associated with placental development by controlling EVT invasion and spiral artery remodeling via modulation of EMT, MMP-2, MMP-9, Akt/p38MAPK signaling, and Fas/FasL.

Profiles of circular RNAs in human placenta and their potential roles related to preeclampsia

To identify the profiles of circular RNAs (circRNAs) in human placental tissues and to explore the potential roles of dysregulated circRNAs in the pathological genesis of preeclampsia, expression profiles of circRNAs in human placentas were performed in this study. Utilizing high-throughput technology, based on fold changes and P values, 300 circRNAs that are differentially expressed between preeclampsia and normal placental tissues were identified. Among them, hg38_circ_0014736 and hsa_circ_0015382 were validated as significantly upregulated by real-time quantitative PCR with divergent primers. At the same time, hsa_circ_0007121 was significantly downregulated. GO analysis revealed that the three altered circRNAs had a relationship with transcription regulation, proliferation, protein binding, and response to hypoxia. KEGG analysis yielded that apoptosis, Wnt signaling, and HIF-1 pathways were significantly enriched. Interestingly, hsa_circ_0007121 was found to be expressed differently in plasma between preeclampsia and normal pregnancy and this difference could be detected before 20 gestational weeks. Besides, addition receiver operating characteristic (ROC) curve analysis showed that the area under the ROC curve of hsa_circ_0007121 reached 0.72 ([0.59-0.85], P = 0.004) with a sensitivity of 0.77 and specificity of 0.70. Collectively, this study demonstrates the existence of dysregulated circRNAs in the placenta of preeclampsia patients and annotates their potential roles in the pathogenesis of the disease. Encouragingly, hsa_circ_0007121 was found to be a potential noninvasive biomarker for the prediction of preeclampsia.

MicroRNA-16 inhibits migration and invasion via regulation of the Wnt/β-catenin signaling pathway in ovarian cancer

As small non-coding RNA molecules, microRNAs (miRs) function in the regulation of tumorigenesis. Proliferation in ovarian cancer is considered to be associated with miR-16; however, the role of miR-16 in the migration and invasion of ovarian cancer cells remains unclear. The results of the present study demonstrated that miR-16 expression is downregulated in the ovarian cancer SKOV3 and OVCAR3 cell lines compared with that in normal ovarian epithelial cells (OECs). miR-16 overexpression inhibited the proliferation, migration and invasion of SKOV3 and OVCAR3 cells, and decreased the expression of matrix metallopeptidase (MMP)2 and MMP9. Additionally, miR-16 upregulated the expression of cadherin 1, an intercellular adhesion molecule, and downregulated the expression of some mesenchymal markers, including snail family transcriptional repressor 2, snail family transcriptional repressor 1, Vimentin, twist family BHLH transcription factor 1 and cadherin 2 in SKOV3 and OVCAR3 cells. Furthermore, it was indicated that miR-16 overexpression in SKOV3 and OVCAR3 cells resulted in a significant increase in anti-glycogen synthase kinase 3 β expression and a decrease in the expression of Wnt family member 3A, β-catenin, MYC proto-oncogene, BHLH transcription factor and cyclin D1 compared with the NC group. The results of the present study indicated that miR-16 exerts a suppressive effect on cell migration and invasion in ovarian cancer in vitro, through inactivation of the Wnt/β-catenin signaling pathway. The data suggest that miR-16 may be a potential therapeutic agent for the treatment and prevention of ovarian cancer.

Glycogen synthase kinase (GSK) 3 in pregnancy and parturition: a systematic review of literature

Introduction: Multiple factors and pathways have been reported as critical machineries for cell differentiation and survival during pregnancy; a number of them involve glycogen synthase kinase (GSK) 3a/β. Several reports on GSK3's functional role exist; however, the specific role of GSK3 in reproductive tissues and its contribution to normal or abnormal parturition are still unclear. To fill this knowledge gap, a systematic review of literature was conducted to better understand the functional role of GSK3 in various intrauterine tissues during implantation, pregnancy, and parturition.Methods: We conducted a systematic review of literature on GSK3's expression and function reported between 1980 and 2017 in reproductive tissues during pregnancy using three electronic databases (Web of Science, Medline, and ClinicalTrials.gov). Study selection, data extraction, quality assessment and analyses were performed in duplicate by two independent reviewers.Results: A total of 738 citations were identified; 80 were selected for full text evaluation and 25 were included for final review. GSK3's regulation and function were mostly studied in tissues and cells from placentas (12), fetuses (8), uteruses (6), and ovaries (2). GSK3 is primarily reported as a downstream responder of protein kinase B (AKT)-, Wnt-, and reactive oxygen species (ROS)-related pathways where it plays a critical role in cell survival and growth in reproductive tissues.Conclusions: Though GSK3 has been functionally linked to a number of biological processes in reproductive tissues, it has primarily been studied as a secondary signaler of various conserved cell signaling pathways. Lack of scientific rigor in studying GSK3's role in reproductive tissues makes this molecule's function still obscure. No studies have reported GSK3 in the cervix, and very few reports exist in myometrium and decidua. This systematic review suggests more functional and mechanistic studies focusing on GSK3 need to be conducted in reproductive biology.

MicroRNA-590-3p inhibits trophoblast-dependent maternal spiral artery remodeling by repressing low-density lipoprotein receptor-related protein 6

Background

The remodeling of maternal spiral artery following embryo implantation, which relies on well‐regulated trophoblast functions, is a pivotal process to ensure a successful pregnancy. Low‐density lipoprotein receptor‐related protein 6 (LRP6) and microRNAs (miRNAs, miRs) are suggested to be involved in angiogenesis and several vascular diseases; however, their functions in the control of trophoblast remain elusive. We therefore aimed to examine the roles of LRP6 and miR‐590‐3p in the regulation of trophoblast during the remodeling of maternal spiral artery.

Methods

HTR‐8/SVneo cell, a trophoblast cell line, was utilized to study the effects of LRP6 and miR‐590‐3p on apoptosis, cell proliferation, migration, invasion, as well as tube formation. Expression of angiogenic factors placental growth factor (PlGF), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), and activities of canonical Wnt/β‐catenin signaling pathway, which were implicated in the process of artery remodeling, were also examined.

Results

MiR‐590‐3p directly targeted 3′ untranslated region (3′‐UTR) of LRP6 mRNA and repressed LRP6 expression, which in turn inhibited proliferation, migration, invasion, as well as tube formation, and resulted in apoptosis in HTR‐8/SVneo cells. Further, inhibition of LRP6 through miR‐590‐3p significantly suppressed the expression of PlGF, MMPs, and VEGF and reduced the activation of Wnt/β‐catenin signaling pathway.

Conclusion

MicroRNAs‐590‐3p may inhibit trophoblast‐dependent maternal spiral artery remodeling, via both trophoblast invasion and endovascular formation, by repressing LRP6.

Bisphenol A exposure alters placentation and causes preeclampsia-like features in pregnant mice involved in reprogramming of DNA methylation of WNT2

Preeclampsia leads to adverse outcomes for pregnant women. Bisphenol A (BPA) is an environmental endocrine disruptor and has been shown to be positively associated with increased risk of preeclampsia in human studies. We investigated whether BPA exposure causes preeclampsia-like features in pregnant mice and the associated underlying mechanisms. Experiments were performed in animal models and cell cultures. In pregnant mice, BPA-exposed mice exhibited preeclampsia-like features including hypertension, disruption of the circulation, and the placental angiogenesis biomarkers fms-related tyrosine kinase 1 and placenta growth factor, and glomerular atrophy; urinary protein was not affected. These preeclampsia-like features correlated with increased retention of smooth muscle cells and reduced vessel areas at the junctional zone of the placenta. In addition, there were disrupted expression of invasion-related genes including increased tissue inhibitors of metalloproteinases, decreased metalloproteinases, and Wnt family member WNT2/β-catenin, which correlated with increased DNA methylation in its promoter region and upregulation of DNA methyltransferase (Dnmt)1. BPA exposure impeded the interaction between the human cytotrophoblast cell line, HTR-8/SVneo, and endothelium cells. BPA exposure down-regulated WNT2 expression, and elevated the DNA methylation of WNT2; these results were consistent with in vivo observations. Inhibition of DNMT in HTR-8/SVneo cells resulted in reduced DNA methylation and increased expression of WNT2. Taken together, these data demonstrate that BPA exposure alters trophoblast cell invasion and causes abnormal placental vessel remodeling, both of which lead to the development of preeclampsia-like features in pregnant mice. Our results suggest that this phenomenon involves the epigenetic reprogramming and down-regulation of WNT2 mediated by DNMT1.-Ye, Y., Tang, Y., Xiong, Y., Feng, L., Li, X. Bisphenol A exposure alters placentation and causes preeclampsia-like features in pregnant mice involved in reprogramming of DNA methylation of WNT2.

A Potential Role for MMPs during the Formation of Non-Neurogenic Placodes

The formation of non-neurogenic placodes is critical prior to the development of several epithelial derivatives (e.g., feathers, teeth, etc.) and their development frequently involves morphogenetic proteins (or morphogens). Matrix metalloproteinases (MMPs) are important enzymes involved in extracellular matrix remodeling, and recent research has shown that the extracellular matrix (ECM) can modulate morphogen diffusion and cell behaviors. This review summarizes the known roles of MMPs during the development of non-neurogenic structures that involve a placodal stage. Specifically, we discuss feather, hair, tooth, mammary gland and lens development. This review highlights the potential critical role MMPs may play during placode formation in these systems.

SFRP3 negatively regulates placental extravillous trophoblast cell migration mediated by the GCM1-WNT10B-FZD7 axis

Migration of placental extravillous trophoblast (EVT) cells into uterine decidua facilitates the establishment of blood circulation between mother and fetus and is modulated by EVT-decidual cell interaction. Poor or excessive EVT migration is associated with pregnancy complications such as preeclampsia or placenta accreta. Glial cells missing 1 (GCM1) transcription factor is essential for placental development, and decreased GCM1 activity is detected in preeclampsia. To study whether GCM1 regulates trophoblast cell migration, here we showed that GCM1 promotes BeWo and JAR trophoblast cell migration through a novel target gene, WNT10B. Moreover, WNT10B signaling stimulated cytoskeletal remodeling via Rac1 and frizzled 7 (FZD7) was identified as the cognate receptor for WNT10B to up-regulate cell migration. We further showed that secreted frizzled-related protein 3 (SFRP3) is expressed in uterine decidual cells by immunohistochemistry and that SFRP3 expression in telomerase-transformed human endometrial stromal cells (T-HESCs) is elevated under decidualization stimuli and further enhanced by bone morphogenetic protein 2 via SMAD1. SFRP3 blocked the interaction between FZD7 and WNT10B to decrease BeWo cell migration, which corroborated the elevated BeWo cell migration when cocultured with decidualized and SFRP3-knockdown T-HESC monolayer. Our results suggest that GCM1 up-regulates EVT cell migration through WNT10B and FZD7, which is negatively modulated by decidual SFRP3.-Wang, L.-J., Lo, H.-F., Lin, C.-F., Ng, P.-S., Wu, Y.-H., Lee, Y.-S., Cheong, M.-L., Chen, H. SFRP3 negatively regulates placental extravillous trophoblast cell migration mediated by the GCM1-WNT10B-FZD7 axis.

Decreased expression of WNT2 in villi of unexplained recurrent spontaneous abortion patients may cause trophoblast cell dysfunction via downregulated Wnt/β-catenin signaling pathway

WNT2 has been reported to be important for placental development, especially for the proper vascularization of the placenta. However, its precise role in first-trimester trophoblast cells is still unknown. WNT2 expression in the villous tissues of unexplained recurrent spontaneous abortion (URSA) patients was compared with that of healthy women by Western blot. The function of WNT2 in HTR-8/SVneo trophoblast cells was evaluated by altering the cellular WNT2 level through overexpression and shRNA knockdown. The molecular mechanism of the effect of WNT2 on trophoblast cells was investigated. The association of WNT2 with the Wnt/β-catenin signaling pathway was studied through Western blot and immunofluorescence. Results showed that WNT2 protein expression was significantly decreased in villi of the URSA group compared with the control group. In vitro studies showed that WNT2 could promote human trophoblast cell proliferation and migration through activating the Wnt/β-catenin signaling pathway. Moreover, upon the knockdown of WNT2, trophoblast cell proliferation and migration were significantly suppressed. In conclusion, our study indicated that WNT2 plays an important role in trophoblast function. WNT2 insufficiency might cause impaired trophoblast cell proliferation and migration via downregulation of Wnt/β-catenin signaling pathway.

Novel endogenous retrovirus-derived transcript expressed in the bovine placenta is regulated by WNT signaling

Endogenous retroviruses (ERVs) are involved in placentation; perhaps, the most well-known ERVs are the syncytins, actively transcribed env genes involved in cell–cell fusion and possible morphological variations. However, ERVs other than syncytins that play an important role in placental development have not been well characterized. To identify ERV genes expressed during the onset of placentation in the bovine species, we characterized the expression profiles of bovine conceptus transcripts during the peri-attachment period using RNA-seq analysis, and confirming some candidates through real-time PCR. Using in silico and PCR analyses, we identified a novel ERV proviral sequence derived from a gag region, designated bovine endogenous retroviruses (BERV)-K3, containing Gag_p10 and Gag_p24, zinc finger domain. Initial expression of this ERV in bovine conceptuses was on day 20 (day 0 = day of estrus), soon after conceptus attachment to the endometrial epithelium, and its high placental expression was maintained up to the middle of pregnancy. The BERV-K3 transcript was also found in the uterine luminal and glandular epithelia, liver, kidney, intestine, and skin. BERV-K3 is located on chromosome 7 and integrated within LOC100848658, from which noncoding RNA could be transcribed. Furthermore, the expression of endogenous BERV-K3 in bovine trophoblast cell lines was induced by a WNT agonist, a signaling system common to genes expressed in placentas. These data support the argument that during the evolutionary process, mammals incorporated not only similar ERV sequences, but also ERVs unique to individual species. BERV-K3 is in the latter case, likely providing functions unique to ruminant gestation.

Effect of co-culture canine cumulus and oviduct cells with porcine oocytes during maturation and subsequent embryo development of parthenotes in vitro

In the estrus stage, canine oocytes are surrounded by cumulus cells and undergo maturation in the oviduct for 2-3 days after ovulation. We hypothesized that canine oviduct cells (cOC) and canine cumulus cells (cCC) during this stage might affect the maturation of oocytes and thereby improve subsequent embryo development. Therefore, the objective of this study was to compare the effects of a cOC and cCC co-culture on oocyte in vitro maturation (IVM) and subsequent embryo development, and to analyze the gene expressions in a molecular fashion what co-culture actually gives the specific pathways in which the co-culture cells act to improve maturation and embryo development. The effect of co-culture using cOC and cCC on porcine oocyte IVM was investigated. Thereafter, oocytes were activated using electrical stimulation and embryo developmental competence was estimated. The expression of the genes related to oocyte maturation, embryo development and apoptosis were analyzed. Also, reactive oxygen species (ROS) levels after IVM was analyzed. The IVM rate and embryo development including cleavage, blastocyst formation rates, and total blastocyst cell numbers from cOC group were significantly higher than other groups (P < 0.05). The expression of SMAD2/3 and growth differentiation factor 9 (GDF9) was significantly increased in cOC and oocytes from the cOC group compared with other groups. Moreover, the levels of GDF9, prostaglandin-endoperoxide synthase 2 (PTGS2), WNT3A and matrix metalloproteinase 2 (MMP2) were significantly up-regulated in blastocysts from the cOC group. The concentration of ROS was significantly lower in the supernatant of cOC groups compared with other groups. Also, the expression of BCL2 was significantly increased in porcine cumulus cells and oocytes from cOC group. The present study demonstrated that co-culture with cOC improved in vitro porcine oocyte maturation and subsequent embryo development competence. Also, co-culture with cOC during IVM induces a suitable environment for oocyte maturation by enhancing the mRNA level of SMAD2/3 and GDF9, and for embryo development by elevating the expression level of PTGS2, WNT3A and MMP2. In addition, the decreased ROS level in cOC co-culture could have a beneficial influence on oocyte maturation.

Cadmium inhibits placental trophoblast cell migration via miRNA regulation of the transforming growth factor beta (TGF-β) pathway

Preeclampsia (PE), a condition during pregnancy that involves high blood pressure and proteinuria, is potentially fatal to both mother and child. PE currently has no known etiology or cure but has been tied to poor placental trophoblast cell migration. Increased levels of the toxic metal cadmium (Cd) have been associated with increased risk of developing PE, as well as miRNA-associated regulation of the transforming growth factorbeta (TGF-β) pathway. Signal reprogramming of the TGF-β pathway via epigenetic mechanisms is hypothesized to modify placental trophoblast function. In the present study we investigated the role of increased and decreased signaling of the TGF-β pathway in relation to Cd-induced reduction in cellular migration in JEG3 trophoblast cells. Furthermore, the role of a miR-26a as a molecular mediator of placental trophoblast migration was confirmed. The results demonstrate that increased expression of miR-26a and decreased signaling of the TGF-β pathway increase placental cell migration. These findings have relevance for mechanistic understanding of the underpinnings of poor placentation associated with PE.

Wnt/β-catenin signaling pathway in trophoblasts and abnormal activation in preeclampsia (Review)

Preeclampsia (PE) is one of the most common types of hypertensive disease and occurs in 3‑4% of pregnancies. There are a number of theories on the pathogenesis of PE. Abnormal differentiation of the placenta may lead to failure of trophoblast migration, shallow placenta implantation and placental ischemia/hypoxia, followed by the subsequent occurrence of PE. The Wnt/β-catenin pathway is a canonical Wnt‑signaling pathway that regulates several biological processes, including proliferation, migration, invasion and apoptosis. Abnormal activation of the Wnt/β‑catenin signaling pathway may serve an important role in the pathogenesis of various human diseases, particularly in human cancer. Recent studies have demonstrated that the dysregulation of the Wnt/β‑catenin signaling pathway may contribute to PE. The present review aims to summarize the articles on Wnt/β‑catenin signaling pathway in the trophoblast and abnormal activation in PE. Wnt/β-catenin signaling may serve a significant role in the pathogenesis of PE and may be a prospective therapeutic target for the prevention and treatment of PE.

Role of Wnt signalling in early pregnancy

The integration of a complex network of signalling molecules promotes implantation of the blastocyst and development of the placenta. These processes are crucial for a successful pregnancy and fetal growth and development. The signalling network involves both cell-cell and cell-extracellular matrix communication. The family of secreted glycoprotein ligands, the Wnts, plays a major role in regulating a wide range of biological processes, including embryonic development, cell fate, proliferation, migration, stem cell maintenance, tumour suppression, oncogenesis and tissue homeostasis. Recent studies have provided evidence that Wnt signalling pathways play an important role in reproductive tissues and in early pregnancy events. The focus of this review is to summarise our present knowledge of expression, regulation and function of the Wnt signalling pathways in early pregnancy events of human and other model systems, and its association with pathological conditions. Despite our recent progress, much remains to be learned about Wnt signalling in human reproduction. The advancement of knowledge in this area has applications in the reduction of infertility and the incidence and morbidity of gestational diseases.

Notch1 controls development of the extravillous trophoblast lineage in the human placenta

Development of the human placenta and its different epithelial trophoblasts is crucial for a successful pregnancy. Besides fusing into a multinuclear syncytium, the exchange surface between mother and fetus, progenitors develop into extravillous trophoblasts invading the maternal uterus and its spiral arteries. Migration into these vessels promotes remodelling and, as a consequence, adaption of blood flow to the fetal-placental unit. Defects in remodelling and trophoblast differentiation are associated with severe gestational diseases, such as preeclampsia. However, mechanisms controlling human trophoblast development are largely unknown. Herein, we show that Notch1 is one such critical regulator, programming primary trophoblasts into progenitors of the invasive differentiation pathway. At the 12th wk of gestation, Notch1 is exclusively detected in precursors of the extravillous trophoblast lineage, forming cell columns anchored to the uterine stroma. At the 6th wk, Notch1 is additionally expressed in clusters of villous trophoblasts underlying the syncytium, suggesting that the receptor initiates the invasive differentiation program in distal regions of the developing placental epithelium. Manipulation of Notch1 in primary trophoblast models demonstrated that the receptor promotes proliferation and survival of extravillous trophoblast progenitors. Notch1 intracellular domain induced genes associated with stemness of cell columns, myc and VE-cadherin, in Notch1^- fusogenic precursors, and bound to the myc promoter and enhancer region at RBPJκ cognate sequences. In contrast, Notch1 repressed syncytialization and expression of TEAD4 and p63, two regulators controlling self-renewal of villous cytotrophoblasts. Our results revealed Notch1 as a key factor promoting development of progenitors of the extravillous trophoblast lineage in the human placenta.

Regulation of Wnt/β-catenin signaling by herpesviruses

The Wnt/β-catenin signaling pathway is instrumental in successful differentiation and proliferation of mammalian cells. It is therefore not surprising that the herpesvirus family has developed mechanisms to interact with and manipulate this pathway. Successful coexistence with the host requires that herpesviruses establish a lifelong infection that includes periods of latency and reactivation or persistence. Many herpesviruses establish latency in progenitor cells and viral reactivation is linked to host-cell proliferation and differentiation status. Importantly, Wnt/β-catenin is tightly connected to stem/progenitor cell maintenance and differentiation. Numerous studies have linked Wnt/β-catenin signaling to a variety of cancers, emphasizing the importance of Wnt/β-catenin pathways in development, tissue homeostasis and disease. This review details how the alpha-, beta-, and gammaherpesviruses interact and manipulate the Wnt/β-catenin pathway to promote a virus-centric agenda.

Acute alcohol exposure during mouse gastrulation alters lipid metabolism in placental and heart development: Folate prevention

Background

Embryonic acute exposure to ethanol (EtOH), lithium, and homocysteine (HCy) induces cardiac defects at the time of exposure; folic acid (FA) supplementation protects normal cardiogenesis (Han et al., 2009, 2012; Serrano et al., 2010). Our hypothesis is that EtOH exposure and FA protection relate to lipid and FA metabolism during mouse cardiogenesis and placentation.

Methods

On the morning of conception, pregnant C57BL/6J mice were placed on either of two FA‐containing diets: a 3.3 mg health maintenance diet or a high FA diet of 10.5 mg/kg. Mice were injected a binge level of EtOH, HCy, or saline on embryonic day (E) 6.75, targeting gastrulation. On E15.5, cardiac and umbilical blood flow were examined by ultrasound. Embryonic cardiac tissues were processed for gene expression of lipid and FA metabolism; the placenta and heart tissues for neutral lipid droplets, or for medium chain acyl‐dehydrogenase (MCAD) protein.

Results

EtOH exposure altered lipid‐related gene expression on E7.5 in comparison to control or FA‐supplemented groups and remained altered on E15.5 similarly to changes with HCy, signifying FA deficiency. In comparison to control tissues, the lipid‐related acyl CoA dehydrogenase medium length chain gene and its protein MCAD were altered with EtOH exposure, as were neutral lipid droplet localization in the heart and placenta.

Conclusion

EtOH altered gene expression associated with lipid and folate metabolism, as well as neutral lipids, in the E15.5 abnormally functioning heart and placenta. In comparison to controls, the high FA diet protected the embryo and placenta from these effects allowing normal development. Birth Defects Research (Part A) 106:749–760, 2016. © 2016 The Authors Birth Defects Research Part A: Clinical and Molecular Teratology Published by Wiley Periodicals, Inc.

Green tea (-)-epigallocatechin gallate inhibits the growth of human villous trophoblasts via the ERK, p38, AMP-activated protein kinase, and protein kinase B pathways

Green tea catechins, especially (-)-epigallocatechin gallate (EGCG), have been reported to circulate in the placenta of animals and blood of humans after consumption. Whether EGCG regulates activity of human villous trophoblasts (HVT) is unknown. This study investigated the pathways involved in EGCG modulation of trophoblast mitogenesis. EGCG inhibited trophoblast proliferation in a dose-dependent and time-dependent manner, as indicated by the number of cells and incorporation of bromodeoxyuridine (BrdU). EGCG was more effective than other green tea catechins in inhibiting cell growth. EGCG also increased the phosphorylation of the MAPK pathway proteins, ERK1/2, and p38, but not JNK. Furthermore, EGCG had no effects on the total amounts of ERK1/2, p38 MAPK, and JNK proteins. This suggests that EGCG selectively affects particular MAPK subfamilies. Pretreatment with specific inhibitors of ERK1/2, p38 MAPK, and AMP-activated protein kinase (AMPK) antagonized EGCG-induced decreases in both cell number and BrdU incorporation. These inhibitors also blocked EGCG-induced increases in the levels of phospho-ERK1/2, phospho-p38, and phospho-AMPK proteins, respectively. Moreover, EGCG was similar to the phosphatidylinositol 3-kinase inhibitors wortmannin and LY-294002 to decrease protein kinase B (AKT) phosphorylation, cell number, and BrdU incorporation. These data imply that EGCG inhibits the growth of HVT through the ERK, p38, AMPK, and AKT pathways.

CXCR2 is decreased in preeclamptic placentas and promotes human trophoblast invasion through the Akt signaling pathway

INTRODUCTION

CXCR2, the receptor of the CXC chemokines, plays a critical role in cell migration and invasion in many types of cancer. It is unclear what impact CXCR2 may have on Preeclampsia (PE), a pregnancy-specific disease, which is related to insufficient trophoblast invasion. The aim of this study was to investigate the expression pattern of CXCR2 in the placentas of healthy and PE pregnancies, and to investigate the molecular mechanism of CXCR2 involvement in the development of PE.

METHODS

CXCR2 expression levels in newly delivered placentas from 38 pregnant women with PE and 21 healthy pregnant women were detected using quantitative real-time PCR, immunohistochemistry and Western blot assays. The effect of CXCR2 on trophoblast invasion and the underlying mechanisms were examined in two trophoblast cell lines (HTR-8/SVneo and TEV-1 cells).

RESULTS

CXCR2 mRNA and protein expression levels were significantly decreased in preeclamptic placentas than normal control. The invasive abilities of the two trophoblast cell lines were significantly inhibited when CXCR2 was silenced, but that CXCR2 overexpression promoted trophoblast cells invasion. In addition, silencing CXCR2 reduced the expression of matrix metalloproteinase 2 and 9 (MMP2 and MMP9) and phosphorylated Akt (p-Akt). Furthermore, an Akt inhibitor suppressed the expression of MMP-2 and MMP-9.

DISCUSSION

Our results suggest that the decreased CXCR2 may contribute to the development of preeclampsia through impairing trophoblast invasion by down-regulating MMP-2 and MMP-9 via the Akt signaling pathway.

MSX2 Induces Trophoblast Invasion in Human Placenta

Normal implantation depends on appropriate trophoblast growth and invasion. Inadequate trophoblast invasion results in pregnancy-related disorders, such as early miscarriage and pre-eclampsia, which are dangerous to both the mother and fetus. Msh Homeobox 2 (MSX2), a member of the MSX family of homeobox proteins, plays a significant role in the proliferation and differentiation of various cells and tissues, including ectodermal organs, teeth, and chondrocytes. Recently, MSX2 was found to play important roles in the invasion of cancer cells into adjacent tissues via the epithelial-mesenchymal transition (EMT). However, the role of MSX2 in trophoblastic invasion during placental development has yet to be explored. In the present study, we detected MSX2 expression in cytotrophoblast, syncytiotrophoblast, and extravillous cytotrophoblast cells of first or third trimester human placentas via immunohistochemistry analysis. Furthermore, we found that the in vitro invasive ability of HTR8/SVneo cells was enhanced by exogenous overexpression of MSX2, and that this effect was accompanied by increased protein expression of matrix metalloproteinase-2 (MMP-2), vimentin, and β-catenin. Conversely, treatment of HTR8/SVneo cells with MSX2-specific siRNAs resulted in decreased protein expression of MMP-2, vimentin, and β-catenin, and reduced invasion levels in a Matrigel invasion test. Notably, however, treatment with the MSX2 overexpression plasmid and the MSX2 siRNAs had no effect on the mRNA expression levels of β-catenin. Meanwhile, overexpression of MSX2 and treatment with the MSX2-specific siRNA resulted in decreased and increased E-cadherin expression, respectively, in JEG-3 cells. Lastly, the protein expression levels of MSX2 were significantly lower in human pre-eclamptic placental villi than in the matched control placentas. Collectively, our results suggest that MSX2 may induce human trophoblast cell invasion, and dysregulation of MSX2 expression may be associated with pre-eclampsia.

Human Cytomegalovirus Modulates Expression of Noncanonical Wnt Receptor ROR2 To Alter Trophoblast Migration. J Virol. 2015;90:1108-1115. [PMID: 26559837 DOI: 10.1128/jvi.02588-15]

Maternal primary cytomegalovirus (CMV) infection, reactivation, or reinfection with a different viral strain may cause fetal injury and adverse pregnancy outcomes. Increasing evidence indicates that fetal injury results not only from direct viral cytopathic damage to the CMV-infected fetus but also from indirect effects through placental infection and dysfunction. CMV alters Wingless (Wnt) signaling, an essential cellular pathway involved in placentation, as evidenced by reduced transcription of canonical Wnt target genes and decreased Wnt3a-induced trophoblast migration. Whether CMV affects the noncanonical Wnt signaling pathway has been unclear. This study demonstrates for the first time that CMV infection inhibits Wnt5a-stimulated migration of human SGHPL-4 trophoblasts and that inhibition of the pathway restores normal migration of CMV-infected cells. Western blot and real-time PCR analyses show increased expression of noncanonical Wnt receptor ROR2 in CMV-infected trophoblasts. Mimicking the CMV-induced ROR2 protein expression via ectopic expression inhibited Wnt5a-induced trophoblast migration and reduced T cell-specific factor (TCF)/lymphoid enhancer-binding factor (LEF)-mediated transcription as measured using luciferase reporter assays. Gene silencing using small interfering RNA (siRNA) duplexes decreased ROR2 transcript and protein levels. In contrast, proliferation of SGHPL-4 trophoblasts, measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was not affected. The siRNA-mediated downregulation of ROR2 in trophoblasts rescued CMV-induced reduction in trophoblast migration. These data suggest a mechanism where CMV alters the expression of the Wnt receptor ROR2 to alter Wnt5a-mediated signaling and inhibit trophoblast motility. Inhibition of this mechanism may be a target for therapeutic intervention for CMV-induced placental damage and consequent fetal damage in congenital CMV infections.

IMPORTANCE

Maternal primary cytomegalovirus (CMV) infection, reactivation, or reinfection with a different viral strain may cause fetal injury and adverse pregnancy outcomes. Increasing evidence indicates that fetal injury results not only from direct viral cytopathic damage to the CMV-infected fetus but also from indirect effects through placental infection and placental dysfunction. No effective therapy is currently proven to prevent or treat congenital CMV infection. Understanding the molecular underpinnings of CMV infection of the placenta is essential for therapeutic innovations and vaccine design. CMV alters canonical Wingless (Wnt) signaling, an essential cellular pathway involved in placental development. This study suggests a mechanism in which CMV alters the expression of noncanonical Wnt receptor ROR2 to alter motility of placental cells, which has important implications in the pathogenesis of CMV-induced placental dysfunction. Inhibition of this mechanism may be a target for therapeutic intervention for CMV-induced placental damage and consequent fetal damage in congenital CMV infection.

Cell Signaling Pathways Involved During Invasion and Syncytialization of Trophoblast Cells

Implantation involves an extensive cross talk between the trophoblast cells and the receptive endometrium through embryonic as well as endometrial-derived factors that regulate the invasion and migration of trophoblast cells and also syncytia formation. Any aberration in this highly regulated process may lead to pregnancy complications such as preeclampsia, intrauterine growth restriction, or even pregnancy failure. How various cytokines and growth factors act by activating various cell signaling pathways leading to the expression of the effector molecules have been reviewed, which control invasion and migration of trophoblast cells and syncytialization. The gaps in our current understanding of the various signaling pathways, activated by different cytokines/growth factors, their possible cross talk for optimized effector function(s), and future prospects in this field have been discussed.

Excess placental secreted frizzled-related protein 1 in maternal smokers impairs fetal growth

Maternal cigarette smoking during pregnancy remains one of the most common and preventable causes of fetal growth restriction (FGR), a condition in which a fetus is unable to achieve its genetically determined potential size. Even though epidemiologic evidence clearly links maternal cigarette smoking with FGR, insight into the molecular mechanisms of cigarette smoke-induced FGR is lacking. Here, we performed transcriptional profiling of placentas obtained from smoking mothers who delivered growth-restricted infants and identified secreted frizzled-related protein 1 (sFRP1), an extracellular antagonist of endogenous WNT signaling, as a candidate molecule. sFRP1 mRNA and protein levels were markedly upregulated (~10-fold) in placentas from smoking mothers compared with those from nonsmokers. In pregnant mice, adenovirus-mediated overexpression of sFRP1 led to FGR, increased karyorrhexis in the junctional zone, and decreased proliferation of labyrinthine trophoblasts. Consistent with our hypothesis that placental WNT signaling is suppressed in maternal smokers, we found that exposure to carbon monoxide analogs led to reduced WNT signaling, increased SFRP1 mRNA expression, and decreased cellular proliferation in a trophoblast cell line. Moreover, administration of carbon monoxide analogs to pregnant mice in late gestation led to FGR. In summary, our results indicate that the increased placental expression of sFRP1 seen in smokers impairs fetal growth by inhibiting WNT signaling and trophoblast proliferation.

Regulatory Action of Calcium Ion on Cyclic AMP-Enhanced Expression of Implantation-Related Factors in Human Endometrial Cells

Decidualization of human endometrial stroma and gland development is mediated through cyclic AMP (cAMP), but the role of intracellular calcium ion (Ca2+) on cAMP mediated-signaling in human endometrial stroma and glandular epithelia has not been well-characterized. The present study was designed to investigate the role of intracellular Ca2+ on cAMP mediated-decidualization and gland maturation events, which can be identified by the up-regulation of prolactin and IGF-binding protein (IGFBP)1 in human endometrial stromal cells (ESCs), and cyclooxygenase 2 (COX2) and prostaglandin E2 (PGE2) and glandular epithelial EM-1 cells. Increases in decidual prolactin and IGFBP-1 transcript levels, induced by cAMP-elevating agents forskolin or dibutyryl cyclic AMP, were inhibited by Ca2+ influx into ESCs with Ca2+ ionophores (alamethicin, ionomycin) in a dose-dependent manner. Conversely, inhibitors of Ca2+ influx through L-type voltage-dependent Ca2+ channel (VDCC), nifedipine and verapamil, enhanced the decidual gene expression. Furthermore, dantrolene, an inhibitor of Ca2+ release from the intracellular Ca2+ store, up-regulated prolactin and IGFBP-1 expression. Ca2+ ionophores decreased intracellular cAMP concentrations, whereas nifedipine, verapamil or dantrolene increased cAMP concentrations in ESCs. In glandular epithelial cells, similar responses in COX2 expression and PGE2 production were found when intracellular cAMP levels were up-regulated by decreases in Ca2+ concentrations. Thus, a marked decrease in cytosolic Ca2+ levels caused the elevation of cAMP concentrations, resulting in enhanced expression of implantation-related factors including decidual markers. These findings suggest that fluctuation in cytosolic Ca2+ concentrations alters intracellular cAMP levels, which then regulate differentiation of endometrial stromal and glandular epithelial cells.

Oxidative stress-induced C/EBPβ inhibits β-catenin signaling molecule involving in the pathology of preeclampsia

INTRODUCTION

Oxidative stress-induced trophoblast cell dysfunction is a major pathology in preeclampsia (PE). Recently, CCAAT/enhancer binding protein beta (C/EBPβ) has been investigated as a tumor suppressor that participates in tumor invasion. However, the function of C/EBPβ in trophoblast cells remains unknown. Our study was designed to detect the expression of C/EBPβ in the preeclamptic placenta and to identify the underlying mechanisms of oxidative stress.

METHODS

Human placental tissues with PE were collected. The expression of C/EBPβ and β-catenin were detected. Human first trimester extravillous trophoblast cell (HTR8/SVneo) line exposed to hypoxia/reoxygenation (H/R) was employed as an oxidative stress model in vitro to investigate the effects of C/EBPβ on invasion and the expression of β-catenin. Moreover, first trimester-derived placental villous explants were used to verify the effects of C/EBPβ and β-catenin in placentation.

RESULTS

In preeclamptic placentas, C/EBPβ was overexpressed and β-catenin was decreased. In addition, C/EBPβ was found to have increased expression in H/R-treated HTR8/SVneo cells and villous explants. C/EBPβ knockdown and β-catenin activation could significantly promote the invasion of HTR8/SVneo cells, enhance the outgrowth and migration in villous explants and inhibit the excessive generation of intracellular ROS. These findings might be related to the increased activities of MMP-2/9 and the decreased expression of TIMP-1/2. Meanwhile, C/EBPβ knockdown remarkably increased the expression of β-catenin.

DISCUSSION

We hypothesize that the oxidative stress-induced overexpression of C/EBPβ might influence the activity of MMPs by regulating the Wnt/β-catenin signaling pathway to affect the invasion of trophoblast cells, which then participate in the pathogenesis of preeclampsia.

Adaptive mechanisms controlling uterine spiral artery remodeling during the establishment of pregnancy

Implantation of the embryo into the uterus triggers the initiation of hemochorial placentation. The hemochorial placenta facilitates the acquisition of maternal resources required for embryo/fetal growth. Uterine spiral arteries form the nutrient supply line for the placenta and fetus. This vascular conduit undergoes gestation stage-specific remodeling directed by maternal natural killer cells and embryo-derived invasive trophoblast lineages. The placentation site, including remodeling of the uterine spiral arteries, is shaped by environmental challenges. In this review, we discuss the cellular participants controlling pregnancy-dependent uterine spiral artery remodeling and mechanisms responsible for their development and function.

The role of Wnt signaling members in the uterus and embryo during pre-implantation and implantation

Wnt family members are best known for their roles in cell fate determination, differentiation, proliferation and apoptosis during embryonic development. Wnt signaling becomes effective during these cellular processes through the proper interaction between its ligands, receptors, effectors and inhibitors. Here we review Wnt signaling in terms of embryonic development to the blastocyst stage implantation with emphasis on endometrial changes that are critical for receptivity in the uterus. The relationship between Wnt signaling and implantation clearly reveals that, Wnt family members are critical for both early embryonic development and changing of the endometrium before implantation. Specific Wnt signaling pathway members are demonstrated to be critical for endometrial events such as decidualization and endometrial gland formation in addition to cyclic changes in the endometrium controlled by reproductive hormones. In conclusion, specific roles of Wnt members and associated factors for both uterine function and embryonic development should be further investigated with respect to the efficiency of human ARTs.

Wnt3a expression is associated with epithelial-mesenchymal transition and promotes colon cancer progression

Introduction

Epithelial–mesenchymal transition (EMT) contributes to the progression and metastasis of cancer cells and is associated with a more invasive phenotype of cancer. The Wnt/β-catenin signaling pathway is one of the major pathways involved in EMT regulation. Many studies provide evidence that β-catenin, the key regulator of the canonical Wnt signaling pathway, is important in regulating EMT in cancer. However, the roles of Wnt3a, the representative canonical Wnt ligand, in EMT and colon cancer progression have not yet been fully explored.

Methods

The expression levels of Wnt3a and EMT-associated proteins (E-cadherin, vimentin, and β-catenin) were assessed by immunohistochemistry in human colon cancer tissues to evaluate the clinicopathological significance of Wnt3a, as well as the correlation between Wnt3a and EMT. We then upregulated Wnt3a expression in HCT116 colon cancer cells, established a nude mouse xenograft model, detected the expression of EMT and Wnt/β-catenin signaling-associated proteins, and observed invasion and clone-initiating abilities.

Results

In 203 human colon cancer tissue samples, Wnt3a protein overexpression was related to colon cancer histological differentiation (P = 0.004), clinical stage (P = 0.008), presence of metastasis and recurrence (P = 0.036), and survival time (P = 0.007) of colon cancer patients. Wnt3a expression was notably concomitant with EMT immunohistochemical features, such as reduced expression of the epithelial marker E-cadherin (P = 0.012), increased expression of the mesenchymal marker vimentin (P = 0.002), and cytoplasmic distribution of β-catenin (P = 0.021). Results of in vitro and in vivo experiments showed that Wnt3a overexpression could alter cell morphology, regulate EMT-associated protein expression, and enhance clone-initiation and invasion. Dkk1 (antagonist of Wnt/β-catenin signaling) could also partially reverse the expression of EMT-associated proteins in Wnt3a-overexpressing cells.

Conclusions

Wnt3a expression was associated with EMT and promoted colon cancer progression. The EMT-inducing effect was partially due to the stimulative effect of Wnt3a on the Wnt/β-catenin pathway.