Benzo(a)pyrene inhibits migration and invasion of extravillous trophoblast HTR-8/SVneo cells via activation of the ERK and JNK pathway

Epidermal growth factor receptor in placental health and disease: pathways, dysfunction, and chemical disruption

Formation of the placenta during gestation is required to support fetal growth and development. Derived from the placenta, trophoblast cells express nuclear and membrane-bound receptors. Among these receptors is the epidermal growth factor receptor (EGFR) which plays a key role in placental development. Activation of EGFR-mediated signaling in trophoblast cells regulates critical processes, such as proliferation, differentiation, invasion, and fusion during pregnancy, making it essential for normal placental formation. Dysfunction of EGFR in placental trophoblast cells has been associated with adverse pregnancy outcomes, including intrauterine growth restriction, preeclampsia, and preterm birth. Ubiquitous environmental chemicals, like polycyclic aromatic hydrocarbons, polychlorinated biphenyls, organochlorine pesticides, and bisphenols, have been reported to modulate EGFR signaling pathways, potentially contributing to placental dysfunction. This review explores the pivotal role of EGFR signaling in placental development and function, with a focus on how environmental chemicals interfere with EGFR-mediated pathways and placental cell functions as well as their implications for pregnancy outcomes. Findings presented herein underscore the need for further research into the effects of exposure to environmental chemicals on modulating EGFR signaling pathways in the context of placental health.

Exposure to BaA inhibits trophoblast cell invasion and induces miscarriage by regulating the DEC1/ARHGAP5 axis and promoting ubiquitination-mediated degradation of MMP2

Benz[a]anthracene (BaA), a hazardous polycyclic aromatic hydrocarbon classified by the EPA, is a probable reproductive toxicant. Epidemiological studies suggest that BaA exposure may be a risk factor for recurrent miscarriage (RM). However, the underlying mechanisms are not well understood. This study identified DEC1 as a key gene through RNA-seq and single-cell RNA sequencing analysis. DEC1 expression was found to be downregulated in villous tissues from women with RM and in primary extravillous trophoblasts (EVTs) exposed to BaA. BaA suppressed DEC1 expression by promoting abnormal methylation patterns. Further analysis revealed that ARHGAP5 is a direct target of DEC1 in EVTs, where DEC1 inhibits trophoblast invasion by directly regulating ARHGAP5 transcription. Additionally, BaA destabilized matrix metalloproteinase 2 (MMP2) by activating the aryl hydrocarbon receptor (AhR) and promoting E3 ubiquitin ligase MID1-mediated degradation. In a mouse model, BaA induced miscarriage by modulating the DEC1/ARHGAP5 and MID1/MMP2 axes. Notably, BaA-induced miscarriage in mice was prevented by DEC1 overexpression or MID1 knockdown. These findings indicate that BaA exposure leads to miscarriage by suppressing the DEC1/ARHGAP5 pathway and enhancing the MID1/MMP2 pathway in human EVTs.

In vitro blastocyst implantation and trophoblast migration are disrupted by the UV filter benzophenone-3 (BP3)

Benzophenone-3 (BP3) is a common ingredient in personal care products (PCPs) due to its well-established effectiveness in absorbing UV radiation. Sunscreen products are among the most widely used PCPs-containing BP3 applied to the skin, resulting in significant human exposure to BP3 primarily through a dermal application. In the present work, we have tested the action of three environmentally relevant concentrations of BP3 (2, 20 and 200 μg/L) on an in vitro model of implantation of murine blastocysts and on migration ability of the human trophoblast cell line Swan 71. We showed that BP3 caused a significant reduction of blastocyst expansion and a delayed hatching in a non-monotonic way. Besides, embryos displayed a delayed attachment in the three BP3 groups, resulting in a smaller implantation area on the 6th day of culture: BP3(2) (0.32 ± 0.07 mm2); BP3(20) (0.30 ± 0.08 mm2) and BP3(200) (0.25 ± 0.06 mm2) in comparison to the control (0.42 ± 0.07 mm2). We also found a reduced migration capacity of the human first-trimester trophoblast cell line Swan 71 in a scratch assay when exposed to BP3: the lowest dose displayed a higher uncovered area (UA) at 6h when compared to the control, whereas a higher UA of the wound was observed for the three BP3 concentrations at 18 and 24 h of exposure. The changes in UA provoked by BP3 restored to normal values in the presence of flutamide, an androgen receptor (AR) inhibitor. These results indicate that a direct impairment on early embryo implantation and a defective migration of extravillous trophoblast cells through the androgen receptor pathway can be postulated as mechanisms of BP3-action on early gestation with potential impact on fetal growth.

Cell type-dependent response to benzo(a)pyrene exposure of human placental cell lines under normoxic, hypoxic, and pro-inflammatory conditions

Benzo(a)pyrene (BaP) can be detected in the human placenta. However, little is known about the effects of BaP exposure on different placental cells under various conditions. In this study, we aimed to investigate the effects of BaP on mitochondrial function, pyrin domain-containing protein 3 (NLRP3) inflammasome, and apoptosis in three human trophoblast cell lines under normoxia, hypoxia, and inflammatory conditions. JEG-3, BeWo, and HTR-8/SVneo cell lines were exposed to BaP under normoxia, hypoxia, or inflammatory conditions for 24 h. After treatment, we evaluated cell viability, apoptosis, aryl hydrocarbon receptor (AhR) protein and cytochrome P450 (CYP) gene expression, mitochondrial function, including mitochondrial DNA copy number (mtDNAcn), mitochondrial membrane potential (ΔΨm), intracellular adenosine triphosphate (iATP), and extracellular ATP (eATP), nitric oxide (NO), NLPR3 inflammasome proteins, and interleukin (IL)-1β. We found that BaP upregulated the expression of AhR or CYP genes to varying degrees in all three cell lines. Exposure to BaP alone increased ΔΨm in all cell lines but decreased NO in BeWo and HTR-8/SVneo, iATP in HTR-8/SVneo, and cell viability in JEG-3, without affecting apoptosis. Under hypoxic conditions, BaP did not increase the expression of AhR and CYP genes in JEG-3 cells but increased CYP gene expression in two others. Pro-inflammatory conditions did not affect the response of the 3 cell lines to BaP with respect to the expression of CYP genes and changes in the mitochondrial function and NLRP3 inflammasome proteins. In addition, in HTR-8/SVneo cells, BaP increased IL-1β secretion in the presence of hypoxia and poly(I:C). In conclusion, our results showed that BaP affected mitochondrial function in trophoblast cell lines by increasing ΔΨm. This increased ΔΨm may have rescued the trophoblast cells from activation of the NLRP3 inflammasome and apoptosis after BaP treatment. We also observed that different human trophoblast cell lines had cell type-dependent responses to BaP exposure under normoxia, hypoxia, or pro-inflammatory conditions.

Association between urinary polycyclic aromatic hydrocarbons and unexplained recurrent spontaneous abortion from a case-control study

Polycyclic aromatic hydrocarbons (PAHs) have been reported to be associated with adverse pregnancy outcomes. However, there is limited knowledge regarding the effects of single or mixed PAHs exposure on unexplained recurrent spontaneous abortion (URSA). This study aimed to investigate the association between monohydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) and URSA in a case-control study. The results showed that 1-NAP, 2-NAP, 9-FLU, and 1-PYR were detected in 100% of the subjects among measured all sixteen OH-PAHs. Compared with those in the lowest quartiles, participants in the highest quartiles of 3-BAA were associated with a higher risk of URSA (OR (95%CI) = 3.56(1.28-9.85)). With each one-unit increase of ln-transformed 3-BAA, the odds of URSA increased by 41% (OR (95%CI) = 1.41(1.05-1.89)). Other OH-PAHs showed negative or non-significant associations with URSA. Weighted quantile sum (WQS) regression, Bayesian kernel machine regression (BKMR), and quantile-based g-computation (qgcomp) analyses consistently identified 3-BAA as the major contributor to the mixture effect of OH-PAHs on URSA. Our findings suggest that exposure to 3-BAA may be a potential risk factor for URSA. However, further prospective studies are needed to validate our findings in the future.

Association of urinary polycyclic aromatic hydrocarbon metabolites with gestational diabetes mellitus and gestational hypertension among pregnant women in Southwest China: A cross-sectional study

The association of polycyclic aromatic hydrocarbons (PAHs) with gestational diabetes mellitus (GDM) and gestational hypertension during pregnancy has not yet been established. To investigate the association between PAH exposure and GDM and gestational hypertension, we conducted a cross-sectional study of 4206 pregnant women from the Zunyi birth cohort in southwestern China. Gas chromatography/mass spectrometry was used to detect the urinary levels of 10 monohydroxylated PAHs (OH-PAHs). GDM and gestational hypertension were diagnosed and the relevant information was documented by specialist obstetricians and gynecologists. Logistic regression and restricted cubic spline regression were employed to investigate their single and nonlinear associations. Stratified analyses of pregnancy and body mass index data were conducted to determine their moderating effects on the abovementioned associations. Compared with the first quartile of urinary ∑OH-PAHs, the third or fourth quartile in all study participants was associated with an increased risk of GDM (quartile 3: odds ratio [OR] = 1.35, 95% confidence interval [CI]: 1.03-1.77) and gestational hypertension (quartile 3: OR = 1.88, 95% CI: 1.26-2.81; quartile 4: OR = 1.58, 95% CI: 1.04-2.39), respectively. Nonlinear associations of 1-OH-PYR with GDM (cutoff level: 0.02 μg/g creatinine [Cr]) and 1-OH-PHE with gestational hypertension (cutoff level: 0.06 μg/g Cr) were also observed. In pregnant women with overweight or obesity, 1-OH-PHE and 3-OH-PHE were more strongly associated with gestational hypertension. Our results indicate that exposure to PAH during pregnancy may significantly increase the maternal risks of GDM and gestational hypertension; however, this finding still needs to be confirmed through larger-scale prospective studies and biological evidence.

Bifenox compromises porcine trophectoderm and luminal epithelial cells in early pregnancy by arresting cell cycle progression and impairing mitochondrial and calcium homeostasis

Bifenox is a widely used herbicide that contains a diphenyl ether group. However its global usage, the cell physiological effects that induce toxicity have not been elucidated. In this study, the effect of bifenox was examined in porcine trophectoderm and uterine epithelial cells to investigate the potential toxicity of the implantation process. To uncover the toxic effects of bifenox, cell viability and apoptosis following treatment with bifenox were evaluated. To investigate the underlying cellular mechanisms, mitochondrial and calcium homeostasis were investigated in both cell lines. In addition, the dysregulation of cell signal transduction and transcriptional alterations were also demonstrated. Bifenox reduced cell viability and significantly increased the number of cells arrested at the sub-G1 stage. Moreover, bifenox depolarized the mitochondrial membrane and upregulated the calcium flux into the mitochondria in both cell lines. Cytosolic calcium flux increased in porcine trophectoderm (pTr) cells and decreased in porcine luminal epithelium (pLE) cells. In addition, bifenox activated the mitogen-activated protein kinase and phosphoinositide 3-kinase signaling pathways. Furthermore, bifenox inhibited the expression of retinoid receptor genes, such as RXRA, RXRB, and RXRG. Chemokine CCL8 was also downregulated at the mRNA level, whereas CCL5 expression remained unchanged. Overall, the results of this study suggest that bifenox deteriorates cell viability by arresting cell cycle progression, damaging mitochondria, and controlling calcium levels in pTr and pLE cells. The present study indicates the toxic potential of bifenox in the trophectoderm and luminal epithelial cells, which can lead to implantation disorders in early pregnancy.

Interactions between Benzo(a)pyrene exposure and genetic polymorphisms of AhR signaling pathway on missed abortion

Benzo(a)pyrene (BaP) is an environmental pollutant widely exposed to human beings. While the relationship between BaP and missed abortion is few understood. To explore the association between missed abortion and BaP, genetic polymorphisms of AhR pathway, we recruited 112 cases women with missed abortion and 137 controls women with normal pregnancy from Shanxi, China. The BPDE-DNA adducts level in the case group was higher than that in the control group (P < 0.001). The subjects were categorized according to the tertiles of BPDE-DNA adduct concentrations: T1 ( Collapse

Key Words

• AhR signaling pathway
• BaP
• genetic polymorphisms
• missed abortion

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MESH Headings

• Pregnancy
• Humans
• Female
• DNA Adducts
• Benzo(a)pyrene/toxicity
• 7,8-Dihydro-7,8-dihydroxybenzo(a)pyrene 9,10-oxide/metabolism
• Abortion, Missed
• Signal Transduction
• Polymorphism, Genetic

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Affiliation(s)

Sha Liu Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Mei Han Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Jiayu Zhang Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China
Jingru Ji Department of Obstetrics, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China
Yanfei Wu Department of Obstetrics, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China Department of Chinese Medicine, The First Affiliated Hospital, Shanxi Medical University, Taiyuan, Shanxi, China
Junni Wei Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, China

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Effects of polycyclic aromatic hydrocarbons (PAHs) on pregnancy, placenta, and placental trophoblasts

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants that are carcinogenic, mutagenic, endocrine-toxic, and immunotoxic. PAHs can be found in maternal and fetal blood and in the placenta during pregnancy. They may thus affect placental and fetal development. Therefore, the exposure levels and toxic effects of PAHs in the placenta deserve further study and discussion. This review aims to summarize current knowledge on the effects of PAHs and their metabolites on pregnancy and birth outcomes and on placental trophoblast cells. A growing number of epidemiological studies detected PAH-DNA adducts as well as the 16 high-priority PAHs in the human placenta and showed that placental PAH exposure is associated with adverse fetal outcomes. Trophoblasts are important cells in the placenta and are involved in placental development and function. In vitro studies have shown that exposure to either PAH mixtures, benzo(a)pyrene (BaP) or BaP metabolite benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE) affected trophoblast cell viability, differentiation, migration, and invasion through various signaling pathways. Furthermore, similar effects of BPDE on trophoblast cells could also be observed in BaP-treated mouse models and were related to miscarriage. Although the current data show that PAHs may affect placental trophoblast cells and pregnancy outcomes, further studies (population studies, in vitro studies, and animal studies) are necessary to show the specific effects of different PAHs on placental trophoblasts and pregnancy outcomes.

Effects of Xenobiotic Compounds on Preeclampsia and Potential Mechanisms

Preeclampsia (PE) refers to a disease with new hypertension and albuminuria or other end-organ damage after 20 weeks of pregnancy. As a major complication of pregnancy, PE can increase the morbidity and mortality of pregnant women and fetuses and cause serious social burden. Recently, it has been found that exposure to xenobiotic compounds, especially endocrine disruptors in the environment, may contribute to the development of PE. However, the underlying mechanism is still unclear. It is generally believed that PE is related to placental dysplasia, spiral artery remodelling failure, oxidative stress, etc. Therefore, in order to better prevent the occurrence of PE and reduce the damage and impact on mother and fetus, this paper reviews the role and potential mechanism of PE induced by exogenous chemicals and provides an outlook on the environmental etiology of PE.

Regulators involved in trophoblast syncytialization in the placenta of intrauterine growth restriction

Placental dysfunction refers to the insufficiency of placental perfusion and chronic hypoxia during early pregnancy, which impairs placental function and causes inadequate supply of oxygen and nutrients to the fetus, affecting fetal development and health. Fetal intrauterine growth restriction, one of the most common outcomes of pregnancy-induced hypertensions, can be caused by placental dysfunction, resulting from deficient trophoblast syncytialization, inadequate trophoblast invasion and impaired vascular remodeling. During placental development, cytotrophoblasts fuse to form a multinucleated syncytia barrier, which supplies oxygen and nutrients to meet the metabolic demands for fetal growth. A reduction in the cell fusion index and the number of nuclei in the syncytiotrophoblast are found in the placentas of pregnancies complicated by IUGR, suggesting that the occurrence of IUGR may be related to inadequate trophoblast syncytialization. During the multiple processes of trophoblasts syncytialization, specific proteins and several signaling pathways are involved in coordinating these events and regulating placental function. In addition, epigenetic modifications, cell metabolism, senescence, and autophagy are also involved. Study findings have indicated several abnormally expressed syncytialization-related proteins and signaling pathways in the placentas of pregnancies complicated by IUGR, suggesting that these elements may play a crucial role in the occurrence of IUGR. In this review, we discuss the regulators of trophoblast syncytialization and their abnormal expression in the placentas of pregnancies complicated by IUGR.

Effect of benzo[a]pyrene on proliferation and metastasis of oral squamous cell carcinoma cells: A transcriptome analysis based on RNA-seq

Benzo[a]pyrene (BaP), a representative polycyclic aromatic hydrocarbon compound, is a carcinogen that causes head and neck cancers. Despite intensive research, the molecular mechanism of BaP in the development of oral squamous cell carcinoma (OSCC) remains largely unknown. In the present study, the SCC-9 human OSCC cell line was cultured in vitro, separated into treatment groups, and treated with dimethyl sulfoxide or BaP at various concentrations. The malignant behavior ascribed to the BaP treatment was investigated by cell proliferation, clony formation assay, and Transwell assays. Furthermore, transcriptome sequencing was performed to detect the differentially expressed genes, followed by quantitative real-time PCR to measure the expression levels of nine of these genes. Moreover, the Gene Ontology (GO) term and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses showed the biological processes and signaling pathways in which the target genes were involved. Significant effects on SCC-9 cell proliferation, tumorigenicity, cell migration, and invasion were observed after exposure to 8 μM BaP. Additional results revealed that BaP inhibited apoptosis in a dose-dependent manner. The transcriptome sequencing results showed 137 upregulated genes and 135 downregulated genes induced by BaP, associated with tumor-related biological processes and signaling pathways, mainly including transcriptional dysregulation in cancer, the tumor necrosis factor signaling pathway, metabolism of xenobiotics by cytochrome P450, mitogen-activated protein kinase signaling pathway, and so forth. Our study demonstrates that BaP may regulate the expression of certain genes involved in tumor-associated signaling pathways, thereby promoting the proliferative, tumorigenic, and metastatic behaviors of OSCC cells while suppressing their apoptosis.

Toxicity assessments of selected trichloroethylene and perchloroethylene metabolites in three in vitro human placental models

Residential and occupational exposures to the industrial solvents perchloroethylene (PERC) and trichloroethylene (TCE) present public health concerns. In humans, maternal PERC and TCE exposures can be associated with adverse birth outcomes. Because PERC and TCE are biotransformed to toxic metabolites and placental dysfunction can contribute to adverse birth outcomes, the present study compared the toxicity of key PERC and TCE metabolites in three in vitro human placenta models. We measured cell viability and caspase 3 + 7 activity in the HTR-8/SVneo and BeWo cell lines, and caspase 3 + 7 activity in first trimester villous explant cultures. Cultures were exposed for 24 h to 5-100 µM S-(1,2-dichlorovinyl)-L-cysteine (DCVC) and S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC), or 5-200 µM trichloroacetate (TCA) and dichloroacetate (DCA). DCVC significantly reduced cell viability and increased caspase 3 + 7 activity in HTR-8/SVneo cells at a lower concentration (20 µM) compared with concentrations toxic to BeWo cells and villous explants. Similarly, TCVC reduced cell viability and increased caspase 3 + 7 activity in HTR-8/SVneo cells but not in BeWo cells. TCA and DCA had only negligible effects on HTR-8/SVneo or BeWo cells. This study advances understanding of potential risks of PERC and TCE exposure during pregnancy by identifying metabolites toxic in placental cells and tissues.

Prothioconazole induces cell cycle arrest by up-regulation of EIF4EBP1 in extravillous trophoblast cells

Prothioconazole (PTC) is a new broad-spectrum triazole antibacterial agent that is being widely used in agriculture. PTC has been linked to a number of reproductive outcomes including embryo implantation disorder; however, the exact mechanism underlying this relationship has yet to be determined. Proper trophoblast proliferation and migration is a prerequisite for successful embryo implantation. To elucidate the underlying molecular perturbations, we detect the effect of PTC on extravillous trophoblast cells proliferation and migration, and investigate its potential mechanisms. Exposure to different concentrations of PTC (0-500 μM) significantly inhibited the cell viability and migration ability (5 μM PTC exposure), and also caused the cell cycle arrest at the lowest dose (1 μM PTC exposure). Transcriptome analysis revealed that PTC exposure disturbed multiple biological processes including cell cycle and apoptosis, consistent with cell phenotype. Specifically, eukaryotic translation initiation factor 4E binding protein 1 (EIF4EBP1, 4E-BP1) was identified as up-regulated in PTC exposure group and knockdown of EIF4EBP1, and attenuated the G1 phase arrest induced by PTC exposure. In summary, our data demonstrated that 4E-BP1 participated in PTC-induced cell cycle arrest in extravillous trophoblast cells by regulating cyclin D1. These findings shed light on the potential adverse effect of PTC exposure on the embryo implantation.

Extravillous trophoblast migration and invasion: Impact of environmental chemicals and pharmaceuticals

During pregnancy, the migration and invasion of extravillous trophoblasts (EVTs) into the maternal uterus is essential for proper development of the placenta and fetus. During the first trimester, EVTs engraft and remodel maternal spiral arteries allowing for efficient blood flow and the transfer of essential nutrients and oxygen to the fetus. Aberrant migration of EVTs leading to either shallow or deep invasion into the uterus has been implicated in a number of gestational pathologies including preeclampsia, fetal growth restriction, and placenta accreta spectrum. The migration and invasion of EVTs is well-coordinated to ensure proper placentation. However, recent data point to the ability of xenobiotics to disrupt EVT migration. These xenobiotics include heavy metals, endocrine disrupting chemicals, and organic contaminants and have often been associated with adverse pregnancy outcomes. In most instances, xenobiotics appear to reduce EVT migration; however, there are select examples of enhanced motility after chemical exposure. In this review, we provide an overview of the 1) current experimental approaches used to evaluate EVT migration and invasion in vitro, 2) ability of environmental chemicals and pharmaceuticals to enhance or retard EVT motility, and 3) signaling pathways responsible for altered EVT migration that are sensitive to disruption by xenobiotics.

IL-25 promotes trophoblast proliferation and invasion via binding with IL-17RB and associated with PE

INTRODUCTION

Interleukin-25 is a Th2 interleukin and has been shown to influence cell behavior. This study aims to illustrate its affection on extravillous trophoblasts function and association with PE. Methods qPCR and immunohistochemistry demonstrate IL-25 and IL-17RB expression. CCK-8 test and transwell were to access the behavior of HTR8 in the presence or absence of IL-25, IL-25 neutralization antibody. Results EVTs and HTR8 express IL-25 and IL-17RB. IL-25 promotes proliferation and invasion (p< 0.05),which was abolished in the presence of IL-25Ab (p< 0.05). Conclusion: IL-25 may contribute to promote trophoblast invasion and proliferation and abnormal decline of IL-25 might be associated with PE.

METHODS

qPCR and immunohistochemistry (IHC) were used to demonstrate IL-25 and its receptor IL-17RB expression in primary human trophoblasts of normal first- and third- trimester, as well as third-trimester of PE. CCK-8 test and transwell invasion system in vitro were applied separately to access the behavior of trophoblast cell line (HTR8) in the presence or absence of IL-25, IL-25 neutralization antibody (IL-25 Ab).

RESULTS

EVTs and HTR8 express IL-25 and IL-17RB. The expressions increase in third-trimester during normal pregnancy. In PE, both of IL-25 and IL-17RB expressions decrease (p< 0.05). IL-25 for 24 h promoted HTR8 proliferation and invasion (p< 0.05). The effect was abolished in the presence of IL-25Ab (p< 0.05).

CONCLUSION

This study demonstrates that IL-25 may contribute to promote trophoblast invasion and proliferation and abnormal decline of IL-25 might be associated with PE.

Angiopoietin 2 stimulates trophoblast invasion via a mechanism associated with JNK signaling

Extravillous trophoblast cell (EVT) invasion is tightly controlled, and its dysregulation can lead to altered spiral artery remodeling and contribute to a number of different pregnancy complications. Angiopoietin-2 (Ang-2) is expressed by trophoblast cells and various cells in the decidua, and trophoblast cells express its receptor, Tie2. Ang-2 has been shown to play roles in tumor progression and metastasis but it is not known if it also regulates EVT invasion. Here, we show that both the HTR-8/SVneo cell line and primary isolates of human EVT expressed various integrins and the Tie2 receptor, and Ang-2 stimulated their migration and/or invasion. Ang-2 increased expression of matrix metalloproteinase (MMP)2 and MMP9, altered the cytoskeleton of HTR-8/SVneo cells and also induced phosphorylation of Tie2, JNK and c-Jun. Inhibition of p-JNK (using SP600125) blocked the Ang-2 induced invasion of HTR-8/SVneo cells. In addition, inhibition of Tie2 (pexmetinib) and integrin signaling (RGDS and ATN-161) also blocked Ang-2-induced invasion. In conclusion, we demonstrate that Ang-2 can stimulate EVT invasion via a mechanism associated with activation of both the Tie2 receptor and integrins, which appear to work through different pathways; Tie2 through the JNK/c-JUN pathway and integrins through an as yet unidentified pathway(s). We therefore propose that any alterations in Ang-2 expression in the decidua would lead to an imbalance in pro- and anti-invasive factors, disrupting regulation of EVT invasion and spiral artery remodeling and thereby contribute to the etiology of several complications of pregnancy.

Maternal PM2.5 exposure and abnormal placental nutrient transport

Epidemiological studies of human and animal experiments indicated that gestational exposure to atmospheric pollutants could be followed by the abnormal placental development. However, the effects of this exposure on the placental transportation for nutrients have not been systematically investigated. In this study, fine particulate matters (PM_2.5) samples were collected in Taiyuan and pregnant rodent models were administered with 3 mg/kg b.w. PM_2.5 by oropharyngeal aspiration every other day starting on embryonic day 0.5 (E0.5). Then the pregnant mice were sacrificed and their placentas were collected at different time points. The results showed that maternal PM_2.5 exposure (MPE) disrupted the expression of proliferating cell nuclear antigen (PCNA) at all time points and inhibited the cell proliferation in placenta. Following that, the capacity for placental nutrient transport was impaired. The changes at E18.5 were observed most significantly, showing the altered mRNA expression of amino acid, long-chain polyunsaturated fatty acid (LCPUFA), glucose and folate transporters. In addition, the glycogen content was elevated at E18.5, and the triglyceride content was increased at E13.5 and E15.5 and decreased at E18.5 in the placenta after MPE. In a word, the adverse effect induced by MPE revealed that MPE led tothe disruption on the nutrient supply to the developing fetus via modulating the abundance of placental nutrient transporters (PNT).

Toxicological Effects of BPDE on Dysfunctions of Female Trophoblast Cells

Polycyclic aromatic hydrocarbons (PAHs) are widely spread persistent environmental toxicants. Its typical representative benzo[a]pyrene (BaP) is a human carcinogen. BaP can pass through the placental barrier and is finally metabolized into benzo[a]pyren-7, 8-dihydrodiol-9, 10-epoxide (BPDE). BPDE can form DNA adducts, which directly affect the female reproductive health. Based on the special physiological functions of trophoblast cells and its important effect on normal pregnancy, this chapter describes the toxicity and molecular mechanism of BPDE-induced dysfunctions of trophoblast cells. By affecting the invasion, migration, apoptosis, proliferation, inflammation, and hormone secretion of trophoblast cells, BPDE causes diseases such as choriocarcinoma, intrauterine growth restriction, eclampsia, and abortion. In the end, it is expected to provide a scientific basis and prevention approach for women's reproductive health and decision-making basis for the formulation of environmental health standards.

Exposure to wood smoke particles leads to inflammation, disrupted proliferation and damage to cellular structures in a human first trimester trophoblast cell line

The ongoing transition to renewable fuel sources has led to increased use of wood and other biomass fuels. The physiochemical characteristics of biomass combustion derived aerosols depends on appliances, fuel and operation procedures, and particles generated during incomplete combustion are linked to toxicity. Frequent indoor wood burning is related to severe health problems such as negative effects on airways and inflammation, as well as chronic hypoxia and pathological changes in placentas, adverse pregnancy outcome, preterm delivery and increased risk of preeclampsia. The presence of combustion-derived black carbon particles at both the maternal and fetal side of placentas suggests that particles can reach the fetus. Air pollution particles have also been shown to inhibit trophoblast migration and invasion, which are vital functions for the development of the placenta during the first trimester. In this study we exposed a placental first trimester trophoblast cell line to wood smoke particles emitted under Nominal Burn rate (NB) or High Burn rate (HB). The particles were visible inside exposed cells and localized to the mitochondria, causing ultrastructural changes in mitochondria and endoplasmic reticulum. Exposed cells showed decreased secretion of the pregnancy marker human chorionic gonadotropin, increased secretion of IL-6, disrupted membrane integrity, disrupted proliferation and contained specific polycyclic aromatic hydrocarbons (PAHs) from the particles. Taken together, these results suggest that wood smoke particles can enter trophoblasts and have detrimental effects early in pregnancy by disrupting critical trophoblast functions needed for normal placenta development and function. This could contribute to the underlying mechanisms leading to pregnancy complications such as miscarriage, premature birth, preeclampsia and/or fetal growth restriction. This study support the general recommendation that more efficient combustion technologies and burning practices should be adopted to reduce some of the toxicity generated during wood burning.

Induction of proliferative and mutagenic activity by benzo(a)pyrene in PC-3 cells via JAK2/STAT3 pathway

Environmental carcinogen benzo(a)pyrene (BaP) is a representative compound of polycyclic aromatic hydrocarbons (PAHs). BaP is strongly associated with prostate carcinogenesis. However, the molecular mechanism of BaP in development of prostate carcinoma remains largely unknown. The aim of this study was to investigate the effect and mechanism of BaP on the development in prostate cancer. PC-3 cells were exposed to different concentrations of BaP for 24, 48, 72 h, respectively. We analyzed the effect of BaP on PC-3 cell viability, cell cycle, DNA strand breaks, mutagenic activity, and migration. The expression of associated regulatory genes and the effect of JAK2/STAT3 signaling were also measured to explore the relationships among BaP metabolism, the JAK2/STAT3 pathway and proliferative activity in PC-3 cells. We observed significant effects on proliferation, DNA strand breaks and mutagenic activity after BaP exposure in PC-3 cells, and inhibitors of CYP1 and the AhR transcription factor α -naphthoflavone (ANF) and CH223191 treatment clearly reduced both cell survival and mutagenesis associated with BaP exposure. Reduction in G0-G1 phase population and elevation in S phase were observed after BaP exposure. Migratory cells for PC-3 were significantly increased. The results were further confirmed by the expression of mRNA levels in the significant increments of Snail, Slug, MMP-9, CYP1A1, CYP1B1, CycilnD1, CDK4 and significant reduction of E-cadherin. Significant enhancements were found in the expression of JAK2, STAT3 after BaP treatment. Additionally, activator IL-6 significantly enhanced the effect of BaP on cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression in PC-3 cells. Significant reductions in cell survival, mutagenic activity, Cyclin D1, CDK4, Snail, and JAK2/STAT3 expression were found after inhibitor AG490, ANF and CHJ223191 treatment. These findings reveal that BaP enhances the proliferative and mutagenic activity via JAK2-STAT3 pathway in PC-3 cells, and provide the additional evidence to understand the crucial role of BaP in prostate cancer carcinogenesis.

Diospyros kaki leaves inhibit HGF/Met signaling-mediated EMT and stemness features in hepatocellular carcinoma

Persimmon (Diospyros kaki L.f.) trees are widely cultivated for their edible fruits in Asia. D. kaki leaves are abundant in phytochemicals that have numerous medicinal properties. Hepatocyte growth factor (HGF) and its receptor Met lead to poor prognosis via the promotion of metastasis and chemoresistance in hepatocellular carcinoma (HCC). Therefore, inhibitors targeting the HGF/Met pathway are regarded as promising drugs against HCC. Here, we investigated the effects of D. kaki leaves on HGF-induced epithelial-to-mesenchymal transition (EMT) and stemness traits in HCC. The ethanol extract of D. kaki leaves (EEDK) markedly suppressed HGF-mediated cell migration and invasion through upregulation of CDH1 and downregulation of SNAI1, VIM, MMP1, MMP2, and MMP9. Moreover, EEDK increased the cytotoxicity of sorafenib, which was reduced by HGF, and decreased the expression of the stemness markers KRT19 and CD44. Additionally, we found a clear correlation between stemness and EMT markers in HCC patients. Importantly, EEDK reduced Met activity and attenuated HGF-mediated activation of JNK/c-Jun. Our findings provide new evidence that EEDK can ameliorate HCC with poor prognosis and aggressive phenotype by blocking HGF/Met signaling.

Comparative Study of PPARγ Targets in Human Extravillous and Villous Cytotrophoblasts

Trophoblasts, as the cells that make up the main part of the placenta, undergo cell differentiation processes such as invasion, migration, and fusion. Abnormalities in these processes can lead to a series of gestational diseases whose underlying mechanisms are still unclear. One protein that has proven to be essential in placentation is the peroxisome proliferator-activated receptor γ (PPARγ), which is expressed in the nuclei of extravillous cytotrophoblasts (EVCTs) in the first trimester and villous cytotrophoblasts (VCTs) throughout pregnancy. Here, we aimed to explore the genome-wide effects of PPARγ on EVCTs and VCTs via treatment with the PPARγ-agonist rosiglitazone. EVCTs and VCTs were purified from human chorionic villi, cultured in vitro, and treated with rosiglitazone. The transcriptomes of both types of cells were then quantified using microarray profiling. Differentially expressed genes (DEGs) were filtered and submitted for gene ontology (GO) annotation and pathway analysis with ClueGO. The online tool STRING was used to predict PPARγ and DEG protein interactions, while iRegulon was used to predict the binding sites for PPARγ and DEG promoters. GO and pathway terms were compared between EVCTs and VCTs with clusterProfiler. Visualizations were prepared in Cytoscape. From our microarray data, 139 DEGs were detected in rosiglitazone-treated EVCTs (RT-EVCTs) and 197 DEGs in rosiglitazone-treated VCTs (RT-VCTs). Downstream annotation analysis revealed the similarities and differences between RT-EVCTs and RT-VCTs with respect to the biological processes, molecular functions, cellular components, and KEGG pathways affected by the treatment, as well as predicted binding sites for both protein-protein interactions and transcription factor-target gene interactions. These results provide a broad perspective of PPARγ-activated processes in trophoblasts; further analysis of the transcriptomic signatures of RT-EVCTs and RT-VCTs should open new avenues for future research and contribute to the discovery of possible drug-targeted genes or pathways in the human placenta.

Exposure to Trichloroethylene Metabolite S-(1,2-Dichlorovinyl)-L-cysteine Causes Compensatory Changes to Macronutrient Utilization and Energy Metabolism in Placental HTR-8/SVneo Cells

Trichloroethylene (TCE) is a widespread environmental contaminant following decades of use as an industrial solvent, improper disposal, and remediation challenges. Consequently, TCE exposure continues to constitute a risk to human health. Despite epidemiological evidence associating exposure with adverse birth outcomes, the effects of TCE and its metabolite S-(1, 2-dichlorovinyl)-L-cysteine (DCVC) on the placenta remain undetermined. Flexible and efficient macronutrient and energy metabolism pathway utilization is essential for placental cell physiological adaptability. Because DCVC is known to compromise cellular energy status and disrupt energy metabolism in renal proximal tubular cells, this study investigated the effects of DCVC on cellular energy status and energy metabolism pathways in placental cells. Human extravillous trophoblast cells, HTR-8/SVneo, were exposed to 5–20 μM DCVC for 6 or 12 h. After establishing concentration and exposure duration thresholds for DCVC-induced cytotoxicity, targeted metabolomics was used to evaluate overall energy status and metabolite concentrations from energy metabolism pathways. The data revealed glucose metabolism perturbations including a time-dependent accumulation of glucose-6-phosphate+frutose-6-phosphate (G6P+F6P) as well as independent shunting of glucose intermediates that diminished with time, with modest energy status decline but in the absence of significant changes in ATP concentrations. Furthermore, metabolic profiling suggested that DCVC stimulated compensatory utilization of glycerol, lipid, and amino acid metabolism to provide intermediate substrates entering downstream in the glycolytic pathway or the tricarboxylic acid cycle. Lastly, amino acid deprivation increased susceptibility to DCVC-induced cytotoxicity. Taken together, these results suggest that DCVC caused metabolic perturbations necessitating adaptations in macronutrient and energy metabolism pathway utilization to maintain adequate ATP levels.

Reduced ELABELA expression attenuates trophoblast invasion through the PI3K/AKT/mTOR pathway in early onset preeclampsia

INTRODUCTION

Early onset preeclampsia is linked to abnormal trophoblast invasion, leading to insufficient recasting of uterine spiral arteries and shallow placental implantation. This study investigated ELABELA (ELA) expression and its involvement in the pathogenesis of early onset preeclampsia.

METHODS

We used immunohistochemistry, quantitative PCR and Western blot to calculate ELA levels in the placentas. Transwell assays were utilize to assess the invasion and migration of trophoblastic Cells. Western blot was used to identify the concentrations of vital kinases in PI3K/AKT/mTOR pathways and invasion-related proteins in trophoblast cells.

RESULTS

ELA was expressed in villous cytotrophoblasts and syncytiotrophoblasts in placental tissue. Compared with the normal pregnancies, ELA mRNA and protein expression was significantly reduced in early onset preeclampsia placentas. In the HTR-8/SVneo cells, when ELA was knocked down, the invasion and migration capability of cells decreased significantly, with MMP2 and MMP9 expression downregulated and the expression of important kinases in the PI3K/AKT/mTOR pathways being significantly decreased compared to the control group. Overexpression of ELA was on the contrary. Besides, while PI3K was blocked, the invasion and migration capability of HTR-8/SVneo cells and the expression of key kinases in PI3K/AKT/mTOR pathways were decreased significantly.

DISCUSSION

ELA stimulates the invasion and migration of trophoblastic cells through activation of downstream PI3K/AKT/mTOR pathway and is complicit in early onset preeclampsia pathogenesis. Our research offers a potential novel treatment for PE.

Marijuana-derived cannabinoids inhibit uterine endometrial stromal cell decidualization and compromise trophoblast-endometrium cross-talk

Marijuana (cannabis) use by pregnant women in the United States is increasing and there is a dire need to understand the beneficial or harmful effects of cannabis during pregnancy. Uterine endometrial stromal cells are fibroblast-like cells that differentiate into secretory cells, a process called decidualization, to create a microenvironment conducive for placenta formation and early embryonic growth. In this study, using model human cell lines, we for the first time demonstrate that Δ9-tetrahydrocannabinol (THC), cannabidiol (CBD) and cannabinol (CBN) inhibit endometrial stromal cell decidualization and have adverse effects on trophoblast-endometrium cross-talk.

Gestational exposure to PM2.5 impairs vascularization of the placenta

The placenta is the bridge that connects the developing fetus and mother and is the place where nutrient uptake, waste elimination and gas exchange occurs. Epidemiological studies indicate that fetal stress, such as gestational PM_2.5 (particulate matter (PM) with diameter ≤ 2.5 μm) exposure, is a risk factor for abnormal placenta development that could induce adverse effects on the fetus. In the present study, PM samples were collected in Taiyuan. Then, pregnant C57BL/6 mice were treated with 3 mg/kg b.w. PM_2.5 every other day starting on GD0.5, and were sacrificed at embryonic day 13.5 (E13.5), E15.5 and E18.5, and placentas were collected for placenta histopathological analysis and gene expression evaluation at the transcription or translation level. Our results showed that gestational exposure to PM_2.5 significantly reduced the ratio of the mean area of labyrinthine (lab) layer/total area of placentas at E18.5. However, no significant difference was observed at E13.5 and E15.5. Interestingly, genes essential for this process were altered at E13.5 and E18.5 but not E15.5. Furthermore, gestational PM_2.5 exposure decreased the mean area of maternal blood sinuses and fetal blood vessels and suppressed protein expression of CD31 in the PM_2.5 group only at E18.5, while protein expression of CD34 in the PM_2.5 group was similar to that in the control group at all time points. Finally, gestational exposure to PM_2.5 activated mitogen-activated protein kinase (MAPK) pathways at E13.5 and E18.5 but not E15.5. Taking these results together, gestational exposure to PM_2.5 leads to histopathological changes and vascularization injuries of the placenta, and this response may be associated with activation of the MAPK pathway.

The Role of Peroxisome Proliferator–Activated Receptor Gamma (PPARγ) in Mono(2-ethylhexyl) Phthalate (MEHP)-Mediated Cytotrophoblast Differentiation

BACKGROUND

Phthalates are environmental contaminants commonly used as plasticizers in polyvinyl chloride (PVC) products. Recently, exposure to phthalates has been associated with preterm birth, low birth weight, and pregnancy loss. There is limited information about the possible mechanisms linking maternal phthalate exposure and placental development, but one such mechanism may be mediated by peroxisome proliferator–activated receptor γ (PPARγ). PPARγ belongs to the nuclear receptor superfamily that regulates, in a ligand-dependent manner, the transcription of target genes. Studies of PPARγ-deficient mice have demonstrated its essential role in lipid metabolism and placental development. In the human placenta, PPARγ is expressed in the villous cytotrophoblast (VCT) and is activated during its differentiation into syncytiotrophoblast.

OBJECTIVES

The goal of this study was to investigate the action of mono(2-ethylhexyl) phthalate (MEHP) on PPARγ activity during in vitro differentiation of VCTs.

METHODS

We combined immunofluorescence, PPARγ activity/hCG assays, western blotting, and lipidomics analyses to characterize the impacts of physiologically relevant concentrations of MEHP (0.1, 1, and 10 μM) on cultured VCTs isolated from human term placentas.

RESULTS

Doses of 0.1 and 1 μM MEHP showed significantly lower PPARγ activity and less VCT differentiation in comparison with controls, whereas, surprisingly, a 10 μM dose had the opposite effect. MEHP exposure inhibited hCG production and significantly altered lipid composition. In addition, MEHP had significant effects on the mitogen-activated protein kinase (MAPK) pathway.

CONCLUSIONS

This study suggests that MEHP has a U-shaped dose–response effect on trophoblast differentiation that is mediated by the PPARγ pathway and acts as an endocrine disruptor in the human placenta. https://doi.org/10.1289/EHP3730.

HGF regulate HTR-8/SVneo trophoblastic cells migration/invasion under hypoxic conditions through increased HIF-1α expression via MAPK and PI3K pathways

Hepatocyte growth factor (HGF) is reported to be down-regulated in pregnancy complications like intrauterine growth retardation and preeclampsia, which are associated with abnormal trophoblast migration/invasion. In this study, role of HGF and associated signaling pathways has been investigated in HTR-8/SVneo trophoblastic cells migration/invasion under normoxia (20% O₂) and hypoxia (2% O₂). HTR-8/SVneo cells exposed to hypoxia showed increase in migration and invasion as compared to cells incubated under normoxic conditions. The migration/invasion under both normoxic and hypoxic conditions was further enhanced after treatment with HGF. Subsequent to treatment with HGF, a significant increase in expression of MMP2 & MMP3 under normoxia and MMP1 & MMP9 under hypoxia was observed. Treatment of HTR-8/SVneo cells with HGF under hypoxia also led to decrease in TIMP1. Treatment of the cells with HGF led to activation of mitogen activated protein kinases (MAPK) and phosphatidylinositol 3-kinase (PI3K) signaling pathways. Inhibition of MAPK by U0126 and PI3K by LY294002 led to concomitant decrease in the HGF-mediated migration/invasion of HTR-8/SVneo cells. HGF treatment under hypoxia also led to a significant increase in hypoxia inducible factor (HIF-1α) expression. Additionally, inhibition of HIF-1α by siRNA led to decrease in HGF-mediated migration of HTR-8/SVneo cells under hypoxic conditions. Inhibition of HGF activated MAPK and PI3K signaling led to reduction in HIF-1α expression under hypoxia. In conclusion, HGF facilitates HTR-8/SVneo cell migration/invasion by activation of MAPK/PI3K signaling pathways and increased expression of MMPs. HIF-1α has a role in HGF-mediated increase in migration under hypoxic conditions.

Down-regulated expressed protein HMGB3 inhibits proliferation and migration, promotes apoptosis in the placentas of fetal growth restriction

Fetal growth restriction (FGR) is one of the major complications of pregnancy, which can lead to serious short-term and long-term diseases. High-mobility group box 3 (HMGB3) has been found to contribute to the development of many cancers. However, the role of HMGB3 in the pathogenesis of FGR is blank. Here, we measured the expression level of HMGB3 in the placenta tissues of six normal pregnancies and five FGR patients by western blotting and quantitative real-time polymerase chain reaction (qRT-PCR). CCK8 assay, transwell assay and flow cytometry were used to detect the functional effects of overexpression and silencing of HMGB3 on the HTR8/SVneo trophoblast cell line. The results showed that the protein levels of HMGB3 were significantly decreased in FGR placentas compared to normal controls, while mRNA levels of HMGB3 were not significantly altered. Furthermore, when overexpressed of protein HMGB3 of the trophoblast cells, the proliferation and migration abilities were significantly promoted, and the apoptosis abilities of these cells were statistically inhibited. Cell functional experiments showed the opposite results when the expression of HMGB3 was silent. And the expression of cell function-related genes PCNA, Ki67, Tp53, Bax, MMP-2 and E-cadherin was observed to show corresponding changes by qRT-PCR. The results of mass spectrometry showed that HMGB3 may directly or indirectly interact with 71 proteins. In summary, our results indicated that HMGB3 might be of very great significance to the pathogenesis of FGR and might play the role by leading the dysfunction of placental villous trophoblast cells and through the interaction with some other proteins.

Involvement of mTOR, JNK and PI3K in the negative effect of ethanol and metformin on the human first-trimester extravillous trophoblast HTR-8/SVneo cell line

Our aim was to investigate the effect of two xenobiotics to which pregnant woman may be exposed, the drug of abuse ethanol (EtOH) (and its metabolite acetaldehyde (ACA)) and the therapeutic agent metformin (METF), on placentation-related processes in an extravillous trophoblastic (EVTs) cell line (HTR-8/SVneo cells). EtOH, ACA and METF (24 h) significantly reduced cell proliferation rates, culture growth, viability and migratory capacity of HTR-8/SVneo cells. Moreover, both EtOH (100 μM) and METF (1 mM) increased the apoptosis index and inhibited ³H-deoxy-D-glucose (³H-DG) and ³H-folic acid (³H-FA) uptake. mTOR, JNK and PI3K intracellular signaling pathways were involved in the effect of EtOH upon ³H-FA uptake and in the effect of METF upon cell viability, and mTOR and JNK in the effect of EtOH upon cell viability and ³H-DG uptake. We show that EtOH and METF have a detrimental effect in placentation-related processes of HTR-8/SVneo cells. Moreover, mTOR, JNK and PI3K appear to mediate some of these negative effects.

Benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide induces human trophoblast Swan 71 cell dysfunctions due to cell apoptosis through disorder of mitochondrial fission/fusion

Benzo(a)pyren-7,8-dihydrodiol-9,10-epoxide (BPDE) is an endocrine disrupter and ultimate carcinogenic product of benzo(a)pyrene (BaP). Numerous studies have shown that BPDE causes trophoblast-related diseases, such as preeclampsia, growth restriction or miscarriages. However, the underlying mechanism, especially the mitochondria-related BPDE-induced trophoblast dysfunction remains unknown. In this study, we examined mitochondrial functions in BPDE-induced human trophoblast cell line Swan 71. BPDE decreased cell ability, attenuated cell invasion and HCG secretion, induced cell apoptosis, decreased mitochondrial membrane potential, increased reactive oxygen species (ROS) and MDA, and decreased SOD activity in a dose-dependent manner. In the mechanism, BPDE significantly increased pro-apoptosis protein (P53 and Bak1) and decreased anti-apoptosis protein (Bcl-2). Furthermore, the protein expression levels of mitochondrial fusion genes (Mfn1, Mfn2, and OPA1) were decreased and those of fission genes (Fis1 and Drp1) were increased with increasing concentrations of BPDE and incubation time, resulting in the release of Cyt c and activation of Caspase 3, which irreversibly induced trophoblast cell apoptosis. This study reveals the mechanism of dysfunction of trophoblast cells through cell apoptosis due to the disorder of mitochondrial fission/fusion after exposure to BPDE, providing a further experimental understanding the adverse effects of BaP on trophoblast cells in early pregnancy.

Trichloroethylene metabolite S-(1,2-dichlorovinyl)-l-cysteine induces lipid peroxidation-associated apoptosis via the intrinsic and extrinsic apoptosis pathways in a first-trimester placental cell line

Trichloroethylene (TCE), a prevalent environmental contaminant, is a potent renal and hepatic toxicant through metabolites such as S-(1, 2-dichlorovinyl)-l-cysteine (DCVC). However, effects of TCE on other target organs such as the placenta have been minimally explored. Because elevated apoptosis and lipid peroxidation in placenta have been observed in pregnancy morbidities involving poor placentation, we evaluated the effects of DCVC exposure on apoptosis and lipid peroxidation in a human extravillous trophoblast cell line, HTR-8/SVneo. We exposed the cells in vitro to 10-100μM DCVC for various time points up to 24h. Following exposure, we measured apoptosis using flow cytometry, caspase activity using luminescence assays, gene expression using qRT-PCR, and lipid peroxidation using a malondialdehyde quantification assay. DCVC significantly increased apoptosis in time- and concentration-dependent manners (p<0.05). DCVC also significantly stimulated caspase 3, 7, 8 and 9 activities after 12h (p<0.05), suggesting that DCVC stimulates the activation of both the intrinsic and extrinsic apoptotic signaling pathways simultaneously. Pre-treatment with the tBID inhibitor Bl-6C9 partially reduced DCVC-stimulated caspase 3 and 7 activity, signifying crosstalk between the two pathways. Additionally, DCVC treatment increased lipid peroxidation in a concentration-dependent manner. Co-treatment with the antioxidant peroxyl radical scavenger (±)-α-tocopherol attenuated caspase 3 and 7 activity, suggesting that lipid peroxidation mediates DCVC-induced apoptosis in extravillous trophoblasts. Our findings suggest that DCVC-induced apoptosis and lipid peroxidation in extravillous trophoblasts could contribute to poor placentation if similar effects occur in vivo in response to TCE exposure, indicating that further studies into this mechanism are warranted.

Environmental contaminants and preeclampsia: a systematic literature review

Preeclampsia is a medical condition specific to pregnancy characterized by high blood pressure and protein in the woman's urine, indicating kidney damage. It is one of the most serious reproductive conditions, posing substantial risks to the baby and potentially fatal for the mother. The causes of preeclampsia are largely unknown and environmental contaminants merit further investigation. The aim of this review was to determine the association between environmental chemical exposures and preeclampsia. PubMed was searched for articles examining a priori chemical exposures and preeclampsia through April 2018. Studies were included in our review if they included at least 10 cases, evaluated preeclampsia independent of gestational hypertension, and used either measured or modeled exposure assessments. Our review contained 28 investigations examining persistent organic pollutants (POP) (6 studies), drinking water contaminants (1 study), atmospheric pollutants (11 studies), metals and metalloids (6 studies), and other environmental contaminants (4 studies). There were an insufficient number of investigations on most chemicals to draw definitive conclusions, but strong evidence existed for an association between preeclampsia and cadmium (Cd). There is suggestive evidence for associations between nitrogen dioxide (NO₂), particulate matter (PM)_2.5, and traffic exposure with preeclampsia. There is evidence for an association between preeclampsia and Cd but insufficient literature to evaluate many other environmental chemicals. Additional studies using repeated measures, appropriate biological matrices, and mixtures methods are needed to expand this area of research and address the limitations of previous studies.

Polycyclic aromatic hydrocarbons and female reproductive health: A scoping review

Polycyclic aromatic hydrocarbons (PAHs) are a class of common persistent environmental pollutants found in water, air, soil, and plants and can be released by natural sources. However, the majority of atmospheric PAHs are from vehicular emissions, coal-burning plants, and the production and use of petroleum-derived substances. Exposure to PAHs has been implicated in cancer and other diseases, including reproductive disorders. This scoping review is a preliminary step that explores the utility and feasibility of completing a systematic review evaluating the effect of PAHs on female reproduction. We performed literature searches in PubMed, Web of Science, and Scopus, then screened, identified, and categorized relevant studies. Our results identified fertility and pregnancy/fetal viability as outcomes with sufficient research for systematic review. In addition to presenting the relevant studies, the review identifies data gaps, and provides the groundwork to develop the most appropriate research questions for systematic review.

Interdependence of JAK-STAT and MAPK signaling pathways during EGF-mediated HTR-8/SVneo cell invasion

Invasion of trophoblast cells is spatio-temporally regulated by various cytokines and growth factors. In pregnancy, complications like preeclampsia, shallow invasion of trophoblast cells and low amounts of epidermal growth factor (EGF) have been reported. In the present study, regulatory mechanisms associated with EGF-mediated invasion in HTR-8/SVneo trophoblastic cells have been delineated. Treatment of HTR-8/SVneo cells with EGF (10 ng/ml) led to eight fold increase (p < 0.05) in invasion. Increased invasion of HTR-8/SVneo cells by EGF was associated with an increase in phosphorylation of ERK½. In addition, significant phosphorylation of STAT1 (ser 727) and STAT3 (both tyr 705 and ser 727 residues) was also observed, accompanied by a decrease in total STAT1. Inhibition of ERK½ phosphorylation by U0126 (10 μM) led to a significant decrease in EGF-mediated invasion with simultaneous decrease in the phosphorylated forms of STAT3 and STAT1. Decrease in total STAT1 was also reversed on inhibition of ERK½. Interestingly, inhibition of STAT3 by siRNA led to a significant decrease in EGF-mediated invasion of HTR-8/SVneo cells and phosphorylation of STAT1, but it did not have any effect on the activation of ERK½. On the other hand, inhibition of STAT1 by siRNA, also led to a significant decrease in the EGF-mediated invasion of HTR-8/SVneo cells, showed concomitant decrease in ERK½ phosphorylation and STAT3 phosphorylation at ser 727 residue. These results suggest cross-communication between ERK½ and JAK-STAT pathways during EGF-mediated increase in invasion of trophoblast cells; phosphorylation at ser 727 residue of both STAT3 and STAT1 appears to be critical.

Role of connexin 43 in cadmium-induced proliferation of human prostate epithelial cells

Connexins (Cxs), the subunits of gap junction channels, are involved in many physiological processes. Aberrant control of Cxs and gap junction intercellular communication may contribute to many diseases, including the promotion of cancer. Cd exposure is associated with increased risk of human prostate cancer and benign prostatic hyperplasia. The roles of Cxs in the effects of Cd on the prostate have, however, not been reported previously. In this study, the human prostate epithelial cell line RWPE-1 was exposed to Cd. A low dose of Cd stimulated cell proliferation along with a lower degree of gap junction intercellular communication and an elevated level of the protein Cx43. Cd exposure increased the levels of intracellular Ca²⁺ and phosphorylated Cx43 at the Ser368 site. Knockdown of Cx43 using siRNA blocked Cd-induced proliferation and interfered with the Cd-induced changes in the protein levels of cyclin D1, cyclin B1, p27^Kip1 (p27) and p21^Waf1/Cip1 (p21). The increase in Cx43 expression induced by Cd was presumably mediated by the androgen receptor, because it was abolished upon treatment with the androgen receptor antagonist, flutamide. Thus, a low dose of Cd promotes cell proliferation in RWPE-1, possibly mediated by Cx43 expression through an effect on cell cycle-associated proteins. Cx43 might be a target for prostatic diseases associated with Cd exposure. Copyright © 2017 John Wiley & Sons, Ltd.