Dual effect of transforming growth factor β1 on cell adhesion and invasion in human placenta trophoblast cells

Latent-Transforming Growth Factor β-Binding Protein 1/Transforming Growth Factor β1 Complex Drives Antitumoral Effects upon ERK5 Targeting in Melanoma

Melanoma is the deadliest skin cancer, with a poor prognosis in advanced stages. While available treatments have improved survival, long-term benefits are still unsatisfactory. The mitogen-activated protein kinase extracellular signal-regulated kinase 5 (ERK5) promotes melanoma growth, and ERK5 inhibition determines cellular senescence and the senescence-associated secretory phenotype. Here, latent-transforming growth factor β-binding protein 1 (LTBP1) mRNA was found to be up-regulated in A375 and SK-Mel-5 BRAF V600E melanoma cells after ERK5 inhibition. In keeping with a key role of LTBP1 in regulating transforming growth factor β (TGF-β), TGF-β1 protein levels were increased in lysates and conditioned media of ERK5-knockdown (KD) cells, and were reduced upon LTBP1 KD. Both LTBP1 and TGF-β1 proteins were increased in melanoma xenografts in mice treated with the ERK5 inhibitor XMD8-92. Moreover, treatment with conditioned media from ERK5-KD melanoma cells reduced cell proliferation and invasiveness, and TGF-β1-neutralizing antibodies impaired these effects. In silico data sets revealed that higher expression levels of both LTBP1 and TGF-β1 mRNA were associated with better overall survival of melanoma patients. Increased LTBP1 or TGF-β1 expression played a beneficial role in patients treated with anti-PD1 immunotherapy, making a possible immunosuppressive role of LTBP1/TGF-β1 unlikely upon ERK5 inhibition. This study, therefore, identifies additional desirable effects of ERK5 targeting, providing evidence of an ERK5-dependent tumor-suppressive role of TGF-β in melanoma.

Can circulating levels of transforming growth Factor-β1 in early pregnancy serve as a predictive marker of unfavourable outcome?

INTRODUCTION

Transforming Growth Factor (TGF-β1) is an anti-inflammatory pleiotropic cytokine, crucial for maternal immune tolerance towards semi-allograft. It acts as a mediator in achieving successful implantation and maintenance of pregnancy.

METHODS

A total of 300 samples; 150 with Recurrent Pregnancy Loss (RPL) and 150 with no pregnancy loss, in their first trimester were evaluated for circulating levels of TGF-β1 using Enzyme-Linked Immunosorbent Assay (ELISA). Further, the Receiver Operating Characteristics (ROC) analysis was performed to assess the potential of TGF-β1 in the risk prediction of RPL and the prognostic importance in the form of favourable and unfavourable outcome in the existing pregnancy.

RESULTS

The results showed significant elevated levels in women without the history of RPL compared to those with the history of RPL (4783.60 ± 522.95 vs. 4252.18 ± 672.26 pg/mL, p < 0.0001).Further evaluation of follow up data of women with the history of RPL, based on favourable (78%) and unfavourable (22%) outcome of the existent pregnancy showed significantly higher TGF-β1 in women with favourable pregnancy outcome in comparison with those who had a foetal loss (4877.12 ± 460.04 vs. 4075.91 ± 616.17 pg/mL, <0.0001). Furthermore, the Receiver Operating Characteristics (ROC) analysis revealed sufficient importance for risk assessment and very good marker to predict unfavourable event (AUC-0.85, SE = 67%, SP = 88%, p < 0.0001).

CONCLUSION

Certainly TGF-β1 appears to have predictive importance; however additional studies with large sample size are warranted for further validation.

Roles of TGF-β1 in Viral Infection during Pregnancy: Research Update and Perspectives

Transforming growth factor-beta 1 (TGF-β1) is a pleiotropic growth factor playing various roles in the human body including cell growth and development. More functions of TGF-β1 have been discovered, especially its roles in viral infection. TGF-β1 is abundant at the maternal-fetal interface during pregnancy and plays an important function in immune tolerance, an essential key factor for pregnancy success. It plays some critical roles in viral infection in pregnancy, such as its effects on the infection and replication of human cytomegalovirus in syncytiotrophoblasts. Interestingly, its role in the enhancement of Zika virus (ZIKV) infection and replication in first-trimester trophoblasts has recently been reported. The above up-to-date findings have opened one of the promising approaches to studying the mechanisms of viral infection during pregnancy with links to corresponding congenital syndromes. In this article, we review our current and recent advances in understanding the roles of TGF-β1 in viral infection. Our discussion focuses on viral infection during pregnancy, especially in the first trimester. We highlight the mutual roles of viral infection and TGF-β1 in specific contexts and possible functions of the Smad pathway in viral infection, with a special note on ZIKV infection. In addition, we discuss promising approaches to performing further studies on this topic.

Post-warming culture of human vitrified blastocysts with prolactin improves trophoblast outgrowth

BACKGROUND

Human embryos express the prolactin (PRL) receptor at the morula and blastocyst stages. Treatment with PRL from cleavage to the blastocyst stage improves blastocyst outgrowth on fibronectin-coated dishes. However, whether post-warming PRL treatment of blastocysts cultured without PRL could improve outgrowth competence remains unknown. Furthermore, the optimal time for post-warming PRL treatment remains to be ascertained. This study investigated the effects of PRL treatment during recovery culture on human blastocyst outgrowth and its related genes.

METHODS

In total, 374 discarded vitrified blastocysts were randomly allocated to two groups, to be cultured with (n = 208) or without PRL (control; n = 166) for 120 min for recovery, and then plated on fibronectin-coated dishes. The expression level of PRL-interacting genes, blastocyst adhesion rate, outgrowth area, distance of trophoblast migration, and outgrowth degeneration were examined.

RESULTS

The mRNA expression of ezrin, radixin, and moesin, which regulate cell adhesion and invasion by controlling actin reorganization during epithelial-to-mesenchymal transition (EMT), was stimulated by PRL treatment for 120 min. The expression of EMT-related genes, transforming growth factor β1, snail1, and twist1 was also promoted following treatment with PRL for 120 min. PRL-treated blastocysts also exhibited augmented expression of cadherin 2 and transcriptional repression of cadherin 1. Higher mRNA expression of integrin-based focal adhesion-related genes, ITGA5 and ITGB1, was observed after treatment with PRL for 120 min than in the non- and shorter-treatment groups. PRL treatment for 120 min did not alter the rate of blastocyst adhesion to fibronectin-coated dishes 96 h after the outgrowth culture assay. However, multiple linear regression analysis revealed that the outgrowth area was significantly increased in PRL-treated blastocysts. The migration distance of trophoblast cells was significantly increased and degeneration rate was significantly decreased after PRL treatment. Furthermore, a more beneficial effect of PRL treatment on blastocyst outgrowth was observed when the blastocysts were vitrified on day 5 than when they were vitrified on day 6.

CONCLUSIONS

Post-warming culture of human vitrified blastocysts with PRL for 120 min promoted trophoblast outgrowth in vitrified human blastocysts. Furthermore, PRL treatment may reduce outgrowth degeneration by increasing resistance to apoptosis during trophoblast migration.

TGF-β1 Promotes Zika Virus Infection in Immortalized Human First-Trimester Trophoblasts via the Smad Pathway

The Zika virus (ZIKV) is well known for causing congenital Zika syndrome if the infection occurs during pregnancy; however, the mechanism by which the virus infects and crosses the placenta barrier has not been completely understood. In pregnancy, TGF-β1 is abundant at the maternal–fetal interface. TGF-β1 has been reported to enhance rubella virus binding and infection in human lung epithelial cells. Therefore, in this study, we investigate the role of TGF-β1 in ZIKV infection in the immortalized human first-trimester trophoblasts, i.e., Swan.71. The cells were treated with TGF-β1 (10 ng/mL) for two days before being inoculated with the virus (American strain PRVABC59) at a multiplicity of infection of five. The results showed an enhancement of ZIKV infection, as demonstrated by the immunofluorescent assay and flow cytometry analysis. Such enhanced infection effects were abolished using SB431542 or SB525334, inhibitors of the TGF-β/Smad signaling pathway. An approximately 2-fold increase in the virus binding to the studied trophoblasts was found. In the presence of the Smad inhibitors, virus replication was significantly suppressed. An enhancement in Tyro3 and AXL (receptors for ZIKV) expression induced by TGF-β1 was also noted. The results suggest that TGF-β1 promotes the virus infection via the Smad pathway. Further studies should be carried out to clarify the underlying mechanisms of these findings.

Association between transforming growth factor-beta 1 polymorphisms and risk of pre-eclampsia: a meta-analysis

PURPOSE

Pre-eclampsia (PE) is a common pregnancy-specific disorder characterized by hypertension and proteinuria. Previous studies have generated conflicting results regarding the association of transforming growth factor-beta 1 (TGF-β1) gene polymorphisms (+869 T/C, -509 C/T, +915 G/C, and -800 G/A) with PE risk. Therefore, we conducted this meta-analysis to more precisely assess the role of TGF-β1 gene polymorphisms in PE.

METHODS

Eligible studies were retrieved from PubMed, Embase, Web of Science, Elsevier Science Direct, and several Chinese databases. The pooled odds ratios (ORs) and 95% confidence intervals (CIs) were used to calculate the associations.

RESULTS

A total of 11 eligible studies (1463 cases/1754 controls) were included in this meta-analysis. A statistically significant association was found between the TGF-β1 + 869 T/C polymorphism and PE risk in the Asian population and in subgroup analyses of the Hardy-Weinberg equilibrium (HWE) in controls and healthy pregnant controls. There was a statistically significant association between TGF-β1 - 509 C/T polymorphism and PE risk among Asian women, and in the subgroup analysis of healthy pregnant controls. No obvious association was observed under any genetic model for the TGF-β1 + 915 G/C and -800 G/A polymorphisms and PE risk, or between the TGF-β1 + 869 T/C and -509 C/T polymorphisms and severity of PE.

CONCLUSIONS

The present study suggested that the TGF-β1 + 869 T/C and -509 C/T polymorphisms are associated with an increased risk of PE in the Asian population. Further case-controlled studies with larger sample sizes are needed to confirm our results.

miR-2337 induces TGF-β1 production in granulosa cells by acting as an endogenous small activating RNA

Transforming growth factor-β1 (TGF-β1) is essential for ovarian function and female fertility in mammals. Herein, we identified three completely linked variants, including two known variants referred to as c.1583A > G and c.1587A > G and the novel variant c.2074A > C in the porcine TGF-β1 3′-UTR. An important role of these variants in Yorkshire sow fertility was revealed. Variants c.1583A > G and c.1587A > G were located at the miRNA response element (MRE) of miR-2337 and affected miR-2337 regulation of TGF-β1 3′-UTR activity. Interestingly, miR-2337 induces, not reduces the transcription and production of TGF-β1 in granulosa cells (GCs). Mechanistically, miR-2337 enhances TGF-β1 promoter activity via the MRE motif in the core promoter region and alters histone modifications, including H3K4me2, H3K4me3, H3K9me2, and H3K9ac. In addition, miR-2337 controls TGF-β1-mediated activity of the TGF-β signaling pathway and GC apoptosis. Taken together, our findings identify miR-2337 as an endogenous small activating RNA (saRNA) of TGF-β1 in GCs, while miR-2337 is identified as a small activator of the TGF-β signaling pathway which is expected to be a new target for rescuing GC apoptosis and treating low fertility.

Role of Transforming Growth Factor-β1 in Regulating Fetal-Maternal Immune Tolerance in Normal and Pathological Pregnancy

Transforming growth factor-β (TGF-β) is composed of three isoforms, TGF-β1, TGF-β2, and TGF-β3. TGF-β1 is a cytokine with multiple biological functions that has been studied extensively. It plays an important role in regulating the differentiation of immune cells and maintaining immune cell functions and immune homeostasis. Pregnancy is a carefully regulated process. Controlled invasion of trophoblasts, precise coordination of immune cells and cytokines, and crosstalk between trophoblasts and immune cells play vital roles in the establishment and maintenance of normal pregnancy. In this systematic review, we summarize the role of TGF-β1 in regulating fetal-maternal immune tolerance in healthy and pathological pregnancies. During healthy pregnancy, TGF-β1 induces the production of regulatory T cells (Tregs), maintains the immunosuppressive function of Tregs, mediates the balance of M1/M2 macrophages, and regulates the function of NK cells, thus participating in maintaining fetal-maternal immune tolerance. In addition, some studies have shown that TGF-β1 is dysregulated in patients with recurrent spontaneous abortion or preeclampsia. TGF-β1 may play a role in the occurrence and development of these diseases and may be a potential target for the treatment of these diseases.

Cortisol Dose-Dependently Impairs Migration and Tube-like Formation in a Trophoblast Cell Line and Modulates Inflammatory and Angiogenic Genes

Several stimuli can change maternal hormone levels during pregnancy. These changes may affect trophoblastic cells and modulate the development of the embryo and the placental tissue itself. Changes in cortisol levels are associated with impaired trophoblast implantation and function, in addition to other pregnancy complications. This study aims to analyze the effects of low and high doses of cortisol on an extravillous trophoblast cell line, and the effects of various exposures to this hormone. SGHPL-4 cells were treated with cortisol at five doses (0-1000 nM) and two exposures (continuous: 24 h/day; and intermittent: 2 h/day). In intermittent treatment, cortisol acted mainly as an anti-inflammatory hormone, repressing gene expression of kinin B1 receptors, interleukin-6, and interleukin-1β. Continuous treatment modulated inflammatory and angiogenic pathways, significantly repressing angiogenic factors and their receptors. Cortisol affected cell migration and tube-like structures formation. In conclusion, both continuous and intermittent exposure to cortisol repressed the expression of inflammatory genes, while only continuous exposure repressed the expression of angiogenic genes, suggesting that a sustained increase in the levels of this hormone is more harmful than a high short-term increase. Cortisol also impaired tube-like structures formation, and kinin receptors may be involved in this response.

Possible Role of TGF-β1, MMP-2, E-CAD, β-Catenin and Antioxidants in Pathogenesis of Placenta Accreta

Placenta accreta (PA) can be life-threatening due to postpartum hemorrhage and may lead to cesarean hysterectomy. We investigated the expression of Matrix metalloproteinase-2 (MMP-2), β-catenin, E-cadherin (E-CAD), transforming growth factor β1 (TGF-β1), glutathione peroxidase 1 (GPx-1), reduced glutathione (GSH) and superoxide dismutase (SOD) in PA compared to controls to determine if alterations may contribute to PA. Materials and methods: Twenty six PA and 31 controls were evaluated immunohistochemically for expression of MMP-2, β-catenin and E-CAD on villous and extravillous trophoblasts. TGF-β1 and GPx-1 mRNA levels were evaluated by rt-PCR. We measured biochemical levels of GSH and SOD. Results: Significant increases of MMP-2 immunoexpression, GPx-1 mRNA, SOD and GSH levels, decreases in immunoexpression of E-CAD and β-catenin and TGF-β1 mRNA were found in PA. Conclusion: These findings suggest that loss of cell-cell adhesion and increased antioxidants level may have a role in PA.

Roles of TGF-β Superfamily Proteins in Extravillous Trophoblast Invasion

Following embryo implantation, extravillous trophoblasts (EVTs) invade the maternal decidua to a certain extent during early pregnancy, which is critical for normal placentation and successful pregnancy in humans. Although sharing a similar protein structure, the transforming growth factor-β (TGF-β) superfamily members exert divergent functions in regulating EVT invasion, which contributes to a relative balance of TGF-β superfamily proteins in precisely modulating this process at the maternal-fetal interface during the first trimester of pregnancy. This review details recent advances in our understanding of the functions of TGF-β superfamily members and their corresponding receptors, signaling pathways, and downstream molecular targets in regulating human EVT invasion from studies using various in vitro or ex vivo experimental models. Also, the relevance of these discoveries about TGF-β superfamily members to adverse pregnancy outcomes is summarized. The application of 3D culture trophoblast organoids, single-cell sequencing, and microfluidic assays in EVT invasion studies will help better reveal the molecular mechanisms through which TGF-β superfamily members regulate human EVT invasion, shedding light on the development of innovative strategies for predicting, diagnosing, treating, and preventing adverse human pregnancy outcomes related to EVT invasion dysfunction.

Prolactin receptor expression and its role in trophoblast outgrowth in human embryos

RESEARCH QUESTION

What is the gene expression pattern of prolactin receptor (PRLR) in human pre-implantation embryos and what are its functions during the embryonic development and adhesion process?

DESIGN

A total of 405 discarded human vitrified oocytes and embryos donated for research by consenting couples were used in this study. The oocytes and embryos were used to analyse PRLR expression and to evaluate the influence of prolactin (PRL) supplementation in the embryo culture medium on embryo developmental competence and viability. The rates of blastocyst development and adhesion, outgrowth area, cytoskeletal reorganization and nascent adhesion formation were compared between groups.

RESULTS

PRLR expression increased significantly after embryo compaction (P < 0.0001) and blastulation (P < 0.0001). Supplementation of the embryo culture medium with PRL did not improve the developmental rate and morphological grade. In contrast, blastocyst outgrowth was significantly increased in embryos cultured with PRL (P = 0.0004). Phosphorylation of JAK2, downstream of the prolactin receptor family, was markedly higher in the PRL-treated embryos than in embryos cultured without PRL. Furthermore, the expression of mRNAs encoding ezrin-radixin-moesin proteins and epithelial-mesenchymal transition-related genes was stimulated by the activation of PRL-JAK2 signalling. The PRL-treated embryos had higher mRNA expression of integrins than non-treated embryos, and transcriptional repression of cadherin 1 was observed after PRL treatment. More nascent adherent cells expressed focal adhesion kinase and paxillin in PRL-treated embryos than in non-treated embryos.

CONCLUSIONS

Human embryos express PRLR at the morula and blastocyst stages, and PRLR signalling stimulates blastocyst adhesion by promoting integrin-based focal adhesions and cytoskeletal organization during trophoblast outgrowth.

Tuning Trophoblast Motility in a Gelatin Hydrogel via Soluble Cues from the Maternal-Fetal Interface

Trophoblast cells play multiple critical roles in pregnancy, notably modulating blastocyst attachment to the endometrium as well as invading into and actively remodeling the endometrium to facilitate biotransport needs of the growing embryo. Despite the importance of trophoblast invasion for processes essential at early stages of pregnancy, much remains unknown regarding the balance of signaling molecules that may influence trophoblast invasion into the endometrium. The goal of this study was to use three-dimensional trophoblast spheroid motility assays to examine the effect of cues from the maternal-fetal interface on trophoblast motility. We report use of a methacrylamide-functionalized gelatin hydrogel to support quantitative analysis of trophoblast outgrowth area and cell viability. We show that this multidimensional model of trophoblast motility can resolve quantifiable differences in outgrowth area and viability in the presence of a known invasion promoter, epidermal growth factor, and a known invasion inhibitor, transforming growth factor β1. We then investigate the sensitivity of trophoblast motility to cortisol, a hormone associated with exogenous stressors. Together, this approach provides a toolset to investigate the coordinated action of physiological and pathophysiological processes on early stages of trophoblast invasion.

CXCR4 signaling at the fetal-maternal interface may drive inflammation and syncytia formation during ovine pregnancy†

Early pregnancy features complex signaling between fetal trophoblast cells and maternal endometrium directing major peri-implantation events including localized inflammation and remodeling to establish proper placental development. Proinflammatory mediators are important for conceptus attachment, but a more precise understanding of molecular pathways regulating this process is needed to understand how the endometrium becomes receptive to implantation. Both chemokine ligand 12 (CXCL12) and its receptor CXCR4 are expressed by fetal and maternal tissues. We identified this pair as a critical driver of placental angiogenesis, but their additional importance to inflammation and trophoblast cell survival, proliferation, and invasion imply a role in syncytia formation at the fetal-maternal microenvironment. We hypothesized that CXCL12 encourages both endometrial inflammation and conceptus attachment during implantation. We employed separate ovine studies to (1) characterize endometrial inflammation during early gestation in the ewe, and (2) establish functional implications of CXCL12 at the fetal-maternal interface through targeted intrauterine infusion of the CXCR4 inhibitor AMD3100. Endometrial tissues were evaluated for inflammatory mediators, intracellular signaling events, endometrial modifications, and trophoblast syncytialization using western blotting and immunohistochemistry. Endometrial tissue from ewes receiving CXCR4 inhibitor demonstrated dysregulated inflammation and reduced AKT and NFKB, paired with elevated autophagic activity compared to control. Immunohistochemical observation revealed an impairment in endometrial surface remodeling and diminished trophoblast syncytialization following localized CXCR4 inhibition. These data suggest CXCL12-CXCR4 regulates endometrial inflammation and remodeling for embryonic implantation, and provide insight regarding mechanisms that, when dysregulated, lead to pregnancy pathologies such as intrauterine growth restriction and preeclampsia.

miR-18a Contributes to Preeclampsia by Downregulating Smad2 (Full Length) and Reducing TGF-β Signaling

The study investigated the regulation of Smad2 by miR-18a and its role in preeclampsia (PE). Bioinformatics analysis showed that both Smad2 and Smad3 were the predicted targets for miR-18a. Mass spectrum analysis showed that two mature Smad2 isoforms existed in human placenta: full length, Smad2(FL), and that lacking exon3, Smad2(Δexon3). The protein level of Smad2(FL), but not Smad2(Δexon3) or Smad3, was significantly increased in severe PE (sPE) placenta, which was inversely correlated with the level of miR-18a. Elevated Smad2(FL) phosphorylation level appeared in sPE placenta, and Smad2 was colocalized with miR-18a in various subtypes of trophoblasts in human placenta. Smad2(FL) was validated as the direct target of miR-18a in HTR8/SVneo cells. miR-18a enhanced trophoblast cell invasion, which was blocked by the overexpression of Smad2(FL). Furthermore, overexpression of miR-18a repressed Smad2 activation and the inhibition of trophoblast cell invasion by transforming growth factor-β (TGF-β). In conclusion, our results suggest that miR-18a inhibits the expression of Smad2(FL), but not Smad2(Δexon3) or Smad3, which can reduce TGF-β signaling, leading to the enhancement of trophoblast cell invasion. A lack of miR-18a, which results in the upregulation of Smad2(FL), contributes to the development of PE.

MicroRNA-27a inhibits trophoblast cell migration and invasion by targeting SMAD2: Potential role in preeclampsia

Preeclampsia (PE) is a severe idiopathic obstetric complication that occurs worldwide. Insufficient trophoblast invasion is a characteristic of the pathogenesis of PE. MicroRNA-27a (miR-27a) has been reported to be highly expressed in PE placentas. The aim of the present study was to investigate the role and underlying mechanisms of miR-27a in the pathogenesis of PE. The expression level of miR-27a was evaluated in the placenta and serum from patients with PE and healthy pregnant women. Cell Counting Kit-8 and flow cytometry assays were performed to detect human HTR-8/SVneo trophoblast proliferation and apoptosis after miR-27a overexpression or inhibition. In addition, Transwell assays were used to measure cell migration and invasion. A luciferase reporter assay was performed to determine the interaction between miR-27a and SMAD2. The present results suggested that miR-27a expression level was significantly increased in PE placentas and serum. In addition, miR-27a overexpression suppressed cell migratory and invasive abilities, impaired proliferation and promoted apoptosis in human trophoblasts. It was demonstrated that miR-27a may target SMAD and contribute to trophoblast invasion. Collectively, the results of the present study suggested that miR-27a inhibited trophoblast cell migration and invasion by targeting SMAD2, thus presenting a promising therapeutic target for PE.

The uteroplacental contact zone cytokine influence on NK cell cytotoxicity to trophoblasts

OBJECTIVE

The present study was to estimate the role of cytokines for trophoblast death in NK cells presence.

METHODS

This study involves assessment of NK-92 line NK cell cytotoxic activity against JEG-3 line cells, in presence of cytokines. We also assessed the effect of secretory placenta products on NK cell cytotoxic activity toward JEG-3 line cells.

RESULTS

Uteroplacental contact zone cytokines are able to enhance trophoblast mortality both by themselves in case of IL-1β, IL-6, IFNγ, IL-4, TGFβ, bFGF, and also through increasing the cytotoxic potential of NK cells in case of IL-1β, IFNγ, IL-8, TGFβ, and GM-CSF. PLGF decreases NK cell cytotoxicity for trophoblasts. Secretory products of first trimester placenta enhance NK cell cytotoxic potential for trophoblasts.

CONCLUSIONS

Cytokines of the uteroplacental contact zone can appear a mechanism ensuring trophoblast mortality dynamics throughout pregnancy.

HTR-8/SVneo: A model for epithelial to mesenchymal transition in the human placenta

INTRODUCTION

The placenta is a transitory organ essential for proper fetal maturation and growth. Trophoblasts, the main cell type of the placenta, differentiate along the villous or extravillous pathways. The ability of villous cytotrophoblasts to undergo an epithelial-to-mesenchymal transition to form the invasive extravillous trophoblasts is vital for a successful pregnancy outcome. Many trophoblastic cell lines, including HTR-8/SVneo, have been widely used to investigate extravillous trophoblast biology and functions. We have previously reported that HTR-8/SVneo cell line contains a mixed populations of epithelial and mesenchymal cells. Uncovering the mechanisms underlying this heterogeneity is essential for the proper study of normal and pathological placental function.

METHODS

HTR-8/SVneo was subjected to monoclonal isolation, spheroid formation assay and cell sorting to isolate pure epithelial and mesenchymal populations. These fractions were maintained in culture and assessed for expression of epithelial and mesenchymal markers using quantitative real-time PCR and immunofluorescence. In addition, the implication of TGFβ in the EMT process was investigated using a selective inhibitor of TGF-βR1 (A83-01).

RESULTS

Passaging of the pure epithelial population maintained under normal culture condition resulted in a shift to a mesenchymal phenotype. This transition was reduced upon inhibiting TGF-βR1. Similarly, E-cadherin positive HTR-8/SVneo spheroids plated in 2D culture resulted in the emergence of streams of invading mesenchymal cells.

DISCUSSION

HTR-8/SVneo cell line is undergoing EMT under normal culture condition and TGFβ is a key mediator of this process. Our results raise the possibility of using HTR-8/SVneo cell line as a model to investigate EMT in extravillous trophoblast cells.

MicroRNAs in Uteroplacental Vascular Dysfunction

Pregnancy complications of preeclampsia and intrauterine growth restriction (IUGR) are major causes of maternal and perinatal/neonatal morbidity and mortality. Although their etiologies remain elusive, it is generally accepted that they are secondary to placental insufficiency conferred by both failure in spiral artery remodeling and uteroplacental vascular malfunction. MicroRNAs (miRNAs) are small no-coding RNA molecules that regulate gene expression at the post-transcriptional level. Increasing evidence suggests that miRNAs participate in virtually all biological processes and are involved in numerous human diseases. Differentially expressed miRNAs in the placenta are typical features of both preeclampsia and IUGR. Dysregulated miRNAs target genes of various signaling pathways in uteroplacental tissues, contributing to the development of both complications. In this review, we provide an overview of how aberrant miRNA expression in preeclampsia and IUGR impacts the expression of genes involved in trophoblast invasion and uteroplacental vascular adaptation.

Activation of latent transforming growth factor-β1, a conserved function for pregnancy-specific beta 1-glycoproteins

STUDY QUESTION

Do all 10 human pregnancy-specific beta 1-glycoproteins (PSGs) and murine PSG23 activate latent transforming growth factor-β1 (TGF-β1)?

SUMMARY ANSWER

All human PSGs and murine PSG23 activated latent TGF-β1.

WHAT IS KNOWN ALREADY

Two of the 10 members of the PSG1 family, PSG1 and PSG9, were previously shown to activate the soluble small latent complex of TGF-β1, a cytokine with potent immune suppressive functions.

STUDY DESIGN, SIZE, DURATION

Recombinant PSGs were generated and tested for their ability to activate the small latent complex of TGF-β1 in a cell-free ELISA-based assay and in a bioassay. In addition, we tested the ability of PSG1 and PSG4 to activate latent TGF-β bound to the extracellular matrix (ECM) or on the membranes of the Jurkat human T-cell line.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Recombinant PSGs were generated by transient transfection and purified with a His-Trap column followed by gel filtration chromatography. The purified PSGs were compared to vehicle (PBS) used as control for their ability to activate the small latent complex of TGF-β1. The concentration of active TGF-β was measured in an ELISA using the TGF-β receptor II as capture and a bioassay using transformed mink epithelial cells that express luciferase in response to active TGF-β. The specificity of the signal was confirmed using a TGF-β receptor inhibitor. We also measured the binding kinetics of some human PSGs for the latent-associated peptide (LAP) of TGF-β using surface plasmon resonance and determined whether PSG1 and PSG4 could activate the large latent complex of TGF-β1 bound to the ECM and latent TGF-β1 bound to the cell membrane. All experiments were performed in triplicate wells and repeated three times.

MAIN RESULTS AND THE ROLE OF CHANCE

All human PSGs activated the small latent complex of TGF-β1 (P < 0.05 vs. control) and showed similar affinities (KD) for LAP. Despite the lack of sequence conservation with its human counterparts, the ability to activate latent TGF-β1 was shared by a member of the murine PSG family. We found that PSG1 and PSG4 activated the latent TGF-β stored in the ECM (P < 0.01) but did not activate latent TGF-β1 bound to glycoprotein A repetitions predominant (GARP) on the surface of Jurkat T cells.

LIMITATIONS, REASONS FOR CAUTION

The affinity of the interaction of LAP and PSGs was calculated using recombinant proteins, which may differ from the native proteins in their post-translational modifications. We also utilized a truncated form of murine PSG23 rather than the full-length protein. For the studies testing the ability of PSGs to activate membrane-bound TGF-β1, we utilized the T-cell line Jurkat and Jurkat cells expressing GARP rather than primary T regulatory cells. All the studies were performed in vitro.

WIDER IMPLICATIONS OF THE FINDINGS

Here, we show that all human PSGs activate TGF-β1 and that this function is conserved in at least one member of the rodent PSG family. In vivo PSGs could potentially increase the availability of active TGF-β1 from the soluble and matrix-bound latent forms of the cytokine contributing to the establishment of a tolerogenic environment during pregnancy.

LARGE-SCALE DATA

None.

STUDY FUNDING/COMPETING INTEREST(S)

The research was supported by a grant from the Collaborative Health Initiative Research Program (CHIRP). No conflicts of interests are declared by the authors.

The biological function of ELABELA and APJ signaling in the cardiovascular system and pre-eclampsia

Pre-eclampsia (PE) is a pregnancy-specific syndrome that is characterized by hypertension and proteinuria. The etiology of PE is not completely understood but is believed to involve placental insufficiency and maternal vascular damage. Growing evidence supports an important role for the apelin receptor (APJ) system in regulating cardiovascular physiology. There are two vertebrate APJ ligands, APELIN and ELABELA, both of which mediate vasodilatory functions. A recent study linked deficient ELABELA signaling and the development of PE, though the molecular mechanism remains largely unknown. In this review, we summarize the biological function of the ELABELA and APJ system in cardiovascular homeostasis and discuss the potential mechanisms by which ELABELA and APJ regulate placenta trophoblast invasion and vascular functions and participate in the development of PE.

Transforming Growth Factor Beta has Dual Effects on MMP9 and uPA Expression in HTR-8/SVneo Human Trophoblastic Cell Line

Invasion of trophoblast into endometrium is vital for successful pregnancy development. MMP9 and uPA are key proteases in this process, but it is still not clear the regulation of its expression by Transforming Growth Factor Beta (TGF-β), known negative regulator of trophoblast invasion. We evaluated the effect of TGF-β on the transcriptional expression of uPA and MMP9 over time, in HTR- /SVneo trophoblast cells cultured with or without 0.5 % fetal bovine serum, via RT qPCR. The involved transcription factors and signaling pathways were analyzed in silico, using Proscan, Enrich, PCViz and WikiPathway. Results showed that that TGF-β regulates the expression of uPA and MMP9. Serum modified the nature of TGF-β’s effects on uPA expression, from negative without serum to positive with it, showing opposite effects on MMP9 expression. In silico analysis evidenced different transcription factors for each protease, some belonging to TGF-β ssignaling pathway, and crosstalk with MAPK and Wnt/β-catenin pathways. The TGF-β ddual role is discussed proposing that serum affects the cellular context. Transcriptional regulation of MMP9 and uPA by TGF-β is differential and depends on serum presence and evaluation time.

Silencing BRIT1 Facilitates the Abilities of Invasiveness and Migration in Trophoblast Cells

Background

The improper invasion of trophoblast cells (TC) can cause various diseases. BRCT-repeat inhibitor of hTERT expression (BRIT1) is involved in the invasion of tumors. Here, we analyzed the effects of BRIT1 on the invasion of TC.

Material/Methods

The expression of BRIT1 in JEG-3, B6Tert, and HTR8/SVneo cells was evaluated by transcription-quantitative polymerase chain reaction (RT-qPCR) and Western blotting. The viability, invasion, and migration of HTR8/SVneo cells were measured using cell counting kit-8 (CCK-8) and Transwell assays. The activities of pro-matrix metalloproteinase-2 (pro-MMP-2) and pro-MMP-9 were tested by gelatin zymography assay. The levels of invasion- and Wnt/β-catenin pathway-related factors were assessed by RT-qPCR and Western blotting.

Results

Levels of BRIT1 in HTR8/SVneo cells were higher than that of JEG-3 and B6Tert cells. The transfection efficiency of BRIT1 siRNA-2 was better than BRIT1 siRNA-1 in HTR8/SVneo cells. BRIT1 siRNA-2 did not change cell viability, whereas it promoted cell invasion and migration. BRIT1 siRNA-2 enhanced the activities of pro-MMP-2 and pro-MMP-9, as well MMP-2 and MMP-9 levels, and reduced tissue inhibitor of metalloproteinases-1 (TIMP-1) and TIMP-2 expression. Moreover, BRIT1 siRNA-2 significantly increased the levels of Wnt2, Wnt3, and β-catenin.

Conclusions

BRIT1 silencing accelerated the invasion and migration of TC and activated the Wnt/β-catenin pathway. Our results may provide new insights for finding new molecular targets to cure disease caused by insufficient invasion of TC.

Transforming growth factor β1 promotes invasion of human JEG-3 trophoblast cells via TGF-β/Smad3 signaling pathway

Transforming growth factor (TGF)-β1 is involved invasion of human trophoblasts. However, the underlying mechanisms remain unclear. In this study, we performed Transwell assay and found that TGF-β1 promoted the invasion of trophoblast cell line JEG-3. Treatment with TGF-β1 up-regulated the expression of receptor-regulated Smad transcription factors Smad2 and Smad3, and two invasive-associated genes, namely, matrix metallopeptidase (MMP)-9 and MMP-2, in JEG-3 cells. Over-expressing activin receptor-like kinase (ALK) 5, the TGF-β type I receptor (TβRI) enhanced the up-regulation of Smad2, Smad3, MMP-9, and MMP-2 induced by TGF-β1, whereas application of TβRI inhibitor SB431542 diminished the stimulatory effects of TGF-β1 on these genes. Furthermore, transfection of Smad3 and ALK-5 seperately or in combination into JEG-3 cells before TGF-β1 treatment significantly increased the expression of MMP-9 and MMP-2. By contrast, silencing Smad3 and Smad2 by siRNAs significantly decreased the expression of MMP-9 and MMP-2, with Smad3 silence having a more potent inhibitory effect. Inhibiting TβRI with SB431542 or knockdown of Smad3, but not Smad2, abolished the stimulatory effect of TGF-β1 on the invasion of JEG-3 cells. Taken together, the results indicate that TGF-β1 activates the Smads signaling pathway in JEG-3 trophoblast cells and Smad3 play a key role in TGF-β1-induced invasion of JEG-3 and up-regulation of MMP-9 and MMP-2 expression.

Relationship of SOCS3 and TGF-β with IDO expression in early pregnancy chorionic villi and decidua

We aimed to investigate the expression of suppressors cytokine signaling (SOCS)-3, transforming growth factor (TGF)-β and indoleamine 2,3-dioxygense (IDO) and to analyse the relationship of SOCS3 and TGF-β with IDO expression in early pregnancy chorionic villi and decidua in the maternal-fetal interface. Western blot analysis and immunohistochemical method were used to detect the expression of TGF-β, SOCS3 and IDO in chorionic villi and decidua tissues of normal pregnant women. SOCS3, TGF-β and IDO protein was identified in chorionic villi and decidua tissues of normal pregnant women and there was a negative correlation between the expression of IDO and SOCS3, but TGF-β expression was positively correlated with IDO expression. The levels of IDO expression in the decidua from normal pregnancies were significantly higher than those in chorionic villi, while the expression of SOCS3 was no significant difference between decidua and chorionic villi. In normal physiological state of pregnancy, SOCS3 and TGF-β may be involved in the regulation of immune tolerance by positive or negative regulation of IDO expression at maternal fetal interface.

Effect of Cytokines on the Formation Tube-Like Structures by Endothelial Cells in the Presence of Trophoblast Cells

Despite ample data on cytokine secretion in the uteroplacental interface, the influence of microenvironment cells, in particular, trophoblast cells on angiogenesis and the role of cytokines in this process remain poorly studied. We studied the influence of cytokines on the formation of tube-like structures by endothelial cells in the presence of trophoblast cells and showed that trophoblast cells suppressed the angiogenic potential of endothelial cells. Antiangiogenic cytokines IFN-γ, IL-10, TNF-α, and TGFβ via modulation of trophoblast cells stimulated the formation of tube-like structures by endothelial cells. In the co-culture of endothelial and trophoblast cells, the effects of cytokines changed and they gained additional regulatory functions.

Effective prediction of preeclampsia by measuring serum angiotensin II, urinary angiotensinogen and urinary transforming growth factor β1

The aim of the current study was to analyze serum angiotensin II (Ang II), urinary angiotensinogen (AGT) and urinary transforming growth factor β1 (TGFβ1) levels in relation to the clinical manifestation of preeclampsia, and to explore the effects of circulating and renal renin angiotensin system (RAS) in preeclampsia patients. An enzyme-linked immunosorbent assay was used to evaluate serum Ang II, urinary AGT and urinary TGFβ1 in preeclampsia, pregnancy-induced hypertension and normotensive pregnancy patients. The correlation between urinary AGT and serum Ang II, urinary TGFβ1, blood pressure and urinary albumin/creatinine ratio (ACR) were then analyzed. Receiver operating characteristic (ROC) curves were also constructed. Negative correlations were observed between urinary AGT and blood pressure, and urinary AGT and ACR, whereas positive correlations were found between urinary AGT and serum Ang II, and urinary AFT and TGFβ1. Moreover, the area under the curve (AUC) of AGT was 0.841 [95% confidence interval (CI): 0.742–0.940, P<0.001], which was significantly higher than that of serum Ang II or urinary TGFβ1 (P<0.001). The optimal cut-off value of urinary AGT at 193 ng/l showed a high diagnostic value in preeclampsia. The AUC of combined serum Ang II, urinary AGT and urinary TGFβ1 was 0.918 (95% CI: 0.845–0.990, P<0.001), with a sensitivity of 83.9% and a specificity of 89.7%. Decreased levels of urinary AGT in preeclampsia patients suggested that local renal RAS was suppressed, and this was associated with hypertension and proteinuria. A high value preeclampsia diagnosis could be achieved by measuring urinary AGT or a combination of urinary AGT, serum Ang II and urinary TGFβ1.

Epithelial-mesenchymal transition during extravillous trophoblast differentiation

A successful pregnancy depends on the intricate and timely interactions of maternal and fetal cells. Placental extravillous cytotrophoblast invasion involves a cellular transition from an epithelial to mesenchymal phenotype. Villous cytotrophoblasts undergo a partial epithelial to mesenchymal transition (EMT) when differentiating into extravillous cytotrophoblasts and gain the capacity to migrate and invade. This review summarizes our current knowledge regarding known regulators of EMT in the human placenta, including the inducers of EMT, upstream transcription factors that control EMT and the downstream effectors, cell adhesion molecules and their differential expression and functions in pregnancy pathologies, preeclampsia (PE) and fetal growth restriction (FGR). The review also describes the research strategies that were used for the identification of the functional role of EMT targets in vitro. A better understanding of molecular pathways driven by placental EMT and further elucidation of signaling pathways underlying the developmental programs may offer novel strategies of targeted therapy for improving feto-placental growth in placental pathologies including PE and FGR.

Molecular Cross-Talk at the Feto-Maternal Interface

Molecular cross-talk at the feto-maternal interface occurs between many different cell types, including uterine leukocytes, extravillous trophoblast cells, and uterine spiral arteries, is essential for the establishment and maintenance of pregnancy. This review concentrates on human pregnancy and examines three main areas in which cross-talk occurs; immune tolerance, regulation of extravillous trophoblast invasion, and remodeling of the uterine spiral arteries.

Effects of transforming growth factor-β1 on the proliferation and invasion of the HTR-8/SVneo cell line

Transforming growth factor-β1 (TGF-β1) is involved in the regulation of trophoblast cell proliferation and invasion. However, the mechanism underlying this process remains unknown, which is predominantly due to the difficulty in obtaining and maintaining primary trophoblast cells in culture over a long period of time. The HTR-8/SVneo cell line is an immortalized trophoblast cell line, which has been reported to exhibit a number of similar characteristics to those of parental trophoblast cells. Therefore, the cell line has been a useful tool for the investigation of placental function and tumor progression. In the present study, the HTR-8/SVneo cell line was used as a model to investigate the TGF-β1/SMAD signaling pathway in the proliferation and invasion of trophoblast cells. The proliferation and invasion ability of HTR-8/SVneo cells was determined using the MTT and Transwell assays, respectively. In addition, reverse transcription polymerase chain reactions were performed to detect the mRNA expression of a panel of known downstream mediators of TGF-β1, including TGF-β receptor I (TβRI), SMAD4, SMAD3, SMAD7 and tissue inhibitor of metalloproteinases-1 (TIMP-1). The results indicated that TGF-β1 promotes the proliferation and invasion of the HTR-8/SVneo cell line at passage 90. Furthermore, the expression of TβRI, SMAD3 and SMAD4 were reduced following treatment with TGF-β1, while the expression of SMAD7 was increased and the expression of TIMP-1 remained unchanged following TGF-β1 treatment. These observations indicated that the effects of TGF-β1 on the proliferation and invasion of the HTR-8/SVneo cell line at passage 90 were different from those of parental trophoblasts, which is in contrast to the results of previous studies. It was concluded that the HTR-8/SVneo cell lines, which have been grown for over 90 passages, do not accurately represent parental trophoblast cells in studies of the TGF-β/SMAD signaling pathway.

The relationship between TGFβ, low oxygen and the outgrowth of extravillous trophoblasts from anchoring villi during the first trimester of pregnancy

BACKGROUND

During the first trimester of human pregnancy, specialised placental cells called extravillous trophoblasts (EVTs) grow out from anchoring villi, invade the maternal decidua and remodel the uterine spiral arteries. Inadequate EVT invasion is associated with pregnancy complications including intrauterine growth restriction (IUGR) and pre-eclampsia. During early pregnancy, the placenta exists in a physiologically normal low oxygen environment, which may regulate EVT outgrowth. One potential oxygen responsive regulator of EVTs is the transforming growth factor-beta (TGFβ) family of cytokines. This work aimed to determine the role of TGFβ1, β2 and β3 in regulating EVT outgrowth in the low oxygen environment of early pregnancy.

RESULTS

Using a quantitative high-throughput first trimester villous explant model of EVT outgrowth we demonstrated no significant difference in the frequency of EVT outgrowth between explants treated with TGFβ1, β2 or β3. However, explants treated with TGFβ2, but not β1 or β3, produced EVT outgrowths with a significantly smaller area in comparison to untreated controls (p=0.03). When explants were cultured in 1.5% oxygen, TGFβ2, but not β1 or β3, in the conditioned medium of explants that produced EVT outgrowth was significantly reduced in comparison to 8% oxygen (p<0.05). There was no significant difference in the concentration of TGFβ2 or TGFβ3 from isolated primary EVTs cultured in 1.5% or 8% oxygen.

CONCLUSIONS

TGFβ2 inhibits EVT outgrowth expansion from first trimester anchoring villi. As TGFβ2 secretion from anchoring villi is down-regulated in low oxygen, these findings suggest that the low oxygen environment in early pregnancy may be important to allow EVT outgrowth expansion and promote adequate placentation.

Transforming growth factor-β1 inhibits trophoblast cell invasion by inducing Snail-mediated down-regulation of vascular endothelial-cadherin protein

Human trophoblast cells express transforming growth factor-β (TGF-β) and TGF-β receptors. It has been shown that TGF-β1 treatment decreases the invasiveness of trophoblast cells. However, the molecular mechanisms underlying TGF-β1-decreased trophoblast invasion are still not fully understood. In the current study, we demonstrated that treatment of HTR-8/SVneo human trophoblast cells with TGF-β1 decreased cell invasion and down-regulated the expression of vascular endothelial cadherin (VE-cadherin). In addition, the inhibitory effect of TGF-β1 on VE-cadherin was confirmed in primary cultures of human trophoblast cells. Moreover, knockdown of VE-cadherin using siRNA decreased the invasiveness of HTR-8/SVneo cells and primary cultures of trophoblast cells. Treatment with TGF-β1 induced the activation of Smad-dependent signaling pathways and the expression of Snail and Slug. Knockdown of Smads attenuated TGF-β1-induced up-regulation of Snail and Slug and down-regulation of VE-cadherin. Interestingly, depletion of Snail, but not Slug, attenuated TGF-β1-induced down-regulation of VE-cadherin. Furthermore, overexpression of Snail suppressed VE-cadherin expression. Chromatin immunoprecipitation analyses showed the direct binding of Snail to the VE-cadherin promoter. These results provide evidence that Snail mediates TGF-β1-induced down-regulation of VE-cadherin, which subsequently contributed to TGF-β1-decreased trophoblast cell invasion.

Homeobox gene transforming growth factor β-induced factor-1 (TGIF-1) is a regulator of villous trophoblast differentiation and its expression is increased in human idiopathic fetal growth restriction

Abnormal trophoblast function is associated with human fetal growth restriction (FGR). Targeted disruption of homeobox gene transforming growth β-induced factor (TGIF-1) results in placental dysfunction in the mouse. The role of human TGIF-1 in placental cell function is unknown. The aims of this study were to determine the expression of TGIF-1 in human idiopathic FGR-affected placentae compared with gestation-matched controls (GMC), to elucidate the functional role of TGIF-1 in trophoblasts and to identify its downstream targets. Real-time PCR and immunoblotting revealed that TGIF-1 mRNA and protein expression was significantly increased in FGR-affected placentae compared with GMC (n = 25 in each group P < 0.05). Immunoreactive TGIF-1 was localized to the villous cytotrophoblasts, syncytiotrophoblast, microvascular endothelial cells and in scattered stromal cells in both FGR and GMC. TGIF-1 inactivation in BeWo cells using two independent siRNA resulted in significantly decreased mRNA and protein of trophoblast differentiation markers, human chorionic gonadotrophin (CGB/hCG), syncytin and 3β-hydroxysteroid dehydrogenase/3β-honest significant difference expression. Our data demonstrate that homeobox gene TGIF-1 is a potential up-stream regulator of trophoblast differentiation and the altered TGIF-1 expression may contribute to aberrant villous trophoblast differentiation in FGR.

MicroRNA-376c impairs transforming growth factor-β and nodal signaling to promote trophoblast cell proliferation and invasion

Preeclampsia is a major disorder of pregnancy and a leading cause of maternal and perinatal morbidity and mortality. MicroRNAs are small noncoding RNAs that regulate gene expression posttranscriptionally. In this study, we examined the expression of miR-376c and found that miR-376c levels were downregulated in both placental and plasma samples collected from preeclamptic patients, when compared with the normal pregnant women at the same gestational stage. Overexpression of miR-376c induced trophoblast cell proliferation, migration, and invasion in HTR8/SVneo cells and promoted placental explant outgrowth. In contrast, inhibition of endogenous miR-376c resulted in a decrease in trophoblast cell invasion and placental explant outgrowth. We identified activin receptor-like kinase 5 (ALK5), a type I receptor for transforming growth factor-β, and ALK7, a type I receptor for Nodal, as targets of miR-376c. Overexpression of miR-376c repressed transforming growth factor-β and Nodal functions, whereas overexpression of ALK5 and ALK7 reversed the effects of miR-376c. These results demonstrate that miR-376c inhibits both ALK5 and ALK7 expression to impair transforming growth factor-β/Nodal signaling, leading to increases in cell proliferation and invasion. An unbalanced Nodal/transforming growth factor-β and miR-376c expression may lead to the development of preeclampsia.

Enantioselectivity in estrogenicity of the organochlorine insecticide acetofenate in human trophoblast and MCF-7 cells

Previous studies have showed that some chiral pesticides with estrogenic activity possess enantioselectivity in endocrine disruption. Despite the assessment of enantioselectivity in the estrogenic potential of chiral pesticides, which deserve particular attention, there has been limited research into their molecular mechanisms of human health risk. In this study, the role of enantioselectivity in the endocrine disruption and potential human maternal-fetal health risk of acetofenate (AF), an organochlorine insecticide, were investigated in both MCF-7 and JEG-3 cells. The two in vitro assays showing a clear enantioselectivity in the estrogenic activity with S-(+)-AF showed stronger effects than R-(-)-AF and rac-AF. Moreover, the racemate's estrogenicity was in between that of enantiomers. Our results also demonstrated that S-(+)-AF possesses the strongest potential effects in disruption of hormone secretion, maternal immune tolerance, and steroidogenesis in the trophoblast. The results suggest that assessment of the health risk of chiral contaminants should consider the role of enantioselectivity.

Characterization of invasive trophoblasts generated from human embryonic stem cells

BACKGROUND

Abnormal human embryo implantation leads to poor foetal development and miscarriage, or pre-eclampsia. Ethical and practical considerations concerning implantation limit its investigation, and it is often difficult to extrapolate findings in laboratory animals when implantation processes show diverse species differences. Therefore, it is important to develop new in vitro models to study the earliest events of human implantation. The aim of this study was to derive trophoblast cell lines from human embryonic stem cells (hESCs) by a robust protocol and co-culture of these cells with an established endometrial cell culture system to validate a model of trophoblast invasion at implantation.

METHODS

Derivation of trophoblast cell lines from hESC lines was established by spontaneous and induced differentiation of embryoid bodies and by initial measurement of hCGβ secretion by enzyme-linked immunosorbent assay and their phenotype investigated using gene- and protein-expression markers. Vesicles formed from an aggregating trophoblast were co-cultured with decidualized human endometrial stromal cells in hypoxic (2% oxygen) and normoxic (20% oxygen) environments.

RESULTS

Derived villous cytotrophoblast cell (CTB) lines further differentiated to invasive, extra-villous CTBs. Eventually, cells lost their proliferative capacity, with some lines acquiring karyotypic changes, such as a gain in the X chromosome. Cell-invasion assays confirmed that the extra-villous CTBs were invasive and erosion of the endometrial stromal layer occurred, particularly under hypoxic conditions in vitro.

CONCLUSIONS

Trophoblast cell lines derived from hESCs differentiate and adapt in vitro and can be used as a model to study the mechanisms of early trophoblast invasion.

Integrative assessment of enantioselectivity in endocrine disruption and immunotoxicity of synthetic pyrethroids

The increasing release of chiral chemicals into the environment dictates attention to a better understanding of enantioselectivity in their human and ecotoxicological effects. Although enantioselectivity has been considered in many recent studies, there is little effort for discerning the connection between different processes, and as such, our current knowledge about chiral contaminants is rather scattered and incoherent. In this study, we simultaneously evaluated enantioselectivity of two chiral pesticides, lambda-cyhalothrin (LCT) and (Z)-cis-bifenthrin (cis-BF), in immunotoxicity to macrophage cells (RAW264.7), and endocrine disruption activity in human breast carcinoma cell line MCF-7. Analysis of cell proliferation, cell viability, apoptosis, and receptor gene expression showed significant differences between the enantiomers of LCT or cis-BF in estrogenic potential and immunocytotoxicity. The selectivity in these effects consistently followed the same direction, with (-)-LCT or 1S-cis-BF displaying a greater activity than its counterpart. The consistency was attributed to interplaying mechanisms in the closely interacting immune and endocrine systems. The underlying interplays suggest that other chiral xenobiotics may also show a directional enantioselectivity in immunotoxicity and endocrine toxicity. Given that many biological processes are inter-related, enantioselectivity may follow specific patterns that can be revealed via integrative assessments as demonstrated in this study.

Induction of oxidative stress and cytotoxicity by PCB126 in JEG-3 human choriocarcinoma cells

The compound 3,3',4,4',5-pentachlorobiphenyl (PCB126) exists in various environmental media, which may have adverse effects on human health. In the present study, induction of the oxidative stress and cytotoxicity by PCB126 were investigated in the human choriocarcinoma cell line JEG-3 cells. Both the reactive oxygen species (ROS) generation and lipid peroxidation production of malondialdehyde (MDA) were obviously increased. Whereas the activity of antioxidant enzymes (superoxide dismutase [SOD] and catalase [CAT]) and glutathione (GSH) content were declined with dose-dependent manners. Furthermore, the result of the cytotoxicity assay showed a clear, dose-dependent growth inhibition effect of PCB126 in JEG-3 cells. Our present results revealed that PCB126 exhibited significant oxidative stress and cytotoxicity in human trophoblast. Given the widespread use of PCBs, a more comprehensive understanding of the significance of reproductive toxicity of PBCs is imperative for improving risk assessment and regulation of these chemicals.

Genes and signals regulating murine trophoblast cell development

A fundamental step in embryonic development is cell differentiation whereby highly specialised cell types are developed from a single undifferentiated, fertilised egg. One of the earliest lineages to form in the mammalian conceptus is the trophoblast, which contributes exclusively to the extraembryonic structures that form the placenta. Trophoblast giant cells (TGCs) in the rodent placenta form the outermost layer of the extraembryonic compartment, establish direct contact with maternal cells, and produce a number of pregnancy-specific cytokine hormones. Giant cells differentiate from proliferative trophoblasts as they exit the cell cycle and enter a genome-amplifying endocycle. Normal differentiation of secondary TGCs is a critical step toward the formation of the placenta and normal embryonic development. Trophoblast development is also of particular interest to the developmental biologist and immunobiologist, as these cells constitute the immediate cellular boundary between the embryonic and maternal tissues. Abnormalities in the development of secondary TGCs results in severe malfunction of the placenta. Herein we review new information that has been accumulated recently regarding the molecular and cellular regulation of trophoblast and placenta development. In particular, we discuss the molecular aspects of murine TGC differentiation. We also focus on the role of growth and transcription factors in TGC development.

Cytokine regulation during the formation of the fetal-maternal interface: focus on cell-cell adhesion and remodelling of the extra-cellular matrix

The establishment of human pregnancy requires the orchestration of substantial cell differentiation and tissue remodelling processes in the context of a complex dialogue between the receptive endometrium and the implanting blastocyst, and is therefore dependent upon a complex sequence of signalling events. Cytokines play an important role in each step of implantation, modulating expression of adhesion molecules on both the fetal and maternal surfaces, regulating expression of the proteases that remodel the extra-cellular matrix, and promoting invasion and differentiation of trophoblasts. Here we review the role of cytokines in regulating the establishment of the fetal-maternal interface, with a particular focus on regulation of the functional expression of CAMs, the ECM and of the proteinases that modulate their function.

Chorionic Villus Sampling as a Source of Trophoblasts

Unlike trophoblasts obtained from pregnancy termination material, trophoblasts grown from explanted chorionic villus samples (CVS) from 11-14 weeks of gestation potentially enable investigation of pre-eclampsia and other pregnancy disorders as the pregnancy outcome will later be known. CVS surplus to diagnostic needs were cultured as explants on either Matrigel or gelatin and the outgrowing cells characterised. Cell morphology was examined and the cells were stained for cytokeratin-7 and HLA-G. Outgrowing trophoblasts co-stained strongly for HLA-G and cytokeratin-7. While outgrowths on Matrigel grew faster and were 100% positive for cytokeratin-7, they proved to be embedded in the matrix and difficult to passage. Outgrowths on gelatin could be released by trypsinisation and were subcultured and further characterised before and after freezing. These cells should prove a valuable resource for the examination of disorders of pregnancy.