Apoptosis Of Placental Cells Research Articles

SIRT5-mediated PRKAA2 succinylation ameliorates apoptosis of human placental trophoblasts in hypertensive disorder complicating pregnancy

ABSTRACT Purpose Hypertensive disorder complicating pregnancy (HDCP) is a serious clinical disorder syndrome during pregnancy. This study aims at finding novel targets for HDCP therapy. Methods HDCP-related mRNAs were firstly screened out and subjected to gene enrichment analysis. We chose protein kinase AMP-activated catalytic subunit alpha 2 (PRKAA2) as the research object. Thirty-nine HDCP patients at 32 to 40 weeks of gestation were selected as the HDCP group, and 39 normal controls who received cesarean section delivery at 37–42 weeks of pregnancy were enrolled in this study. Chorionic villi samples were collected within 30 min of delivery. The apoptosis of isolated placental trophoblasts was monitored to investigate the regulatory role of PRKAA2. Results PRKAA2 expression was further proven to be enhanced in the placental tissues of HDCP patients compared with that of normal puerpera. Subsequently, the results of flow cytometry analysis and western blot indicated that PRKAA2 overexpression accelerated primary placental cell apoptosis, while its knockdown attenuated cell apoptosis. Mechanistically, we determined that the level of PRKAA2 succinylation was elevated in the placental tissue of HDCP patients. Through in vitro succinylation assay and mutagenesis, we confirmed that sirtuin 5 (SIRT5) interacts with PRKAA2 at K69 and K260 to induce PRKAA2 desuccinylation. SIRT5 regulated primary HDCP cell apoptosis through PRKAA2. Finally, the animal study revealed that PRKAA2 elevates the systolic blood pressure of HDCP rat model. Conclusion Our findings indicated that SIRT5-mediated PRKAA2 succinylation modulates placental cell apoptosis in HDCP, suggesting that PRKAA2 is a potential therapeutic target for HDCP treatment.

Echinatin Inhibits Oxidative Stress and Inflammatory Processes in Trophoblast Cells by Inhibiting TLR4-MyD88-NF-κB Pathway in Preeclampsia

Background. Preeclampsia (PE) is a common obstetric disorder hallmarked by impaired trophoblast invasion and a skew toward an inflammatory immune response. Echinatin, a flavonoid with established anti-inflammatory, antioxidant, and anticancer activities, may offer therapeutic benefits in PE. Our study aimed to investigate the effect of echinatin on preeclampsia in vitro and in vivo and to reveal the potential molecular mechanism of its action. Methods. Eighteen adult female Sprague Dawley rats were randomized into three experimental groups: a PE model group, a PE + echinatin treatment group, and a PE + echinatin treatment group with TLR4 overexpression. Placental tissue CK7 expression was assessed by immunohistochemistry. TUNEL immunofluorescence staining quantified placental cell apoptosis. Cell viability, proliferation, and migration were evaluated using cell counting kit-8, EdU incorporation, and Transwell assays, respectively. Oxidative stress parameters of malondialdehyde, superoxide dismutase, and glutathione peroxidase were measured. Flow cytometry determined cell apoptosis and intracellular reactive oxygen species (ROS) levels. Western blotting evaluated the expression of proteins related to the TLR4-MyD88-NF-κB signaling pathway, and the concentrations of TNF-α, IL-6, and IL-18 were measured with ELISA kits. Results. Echinatin mitigated placental damage, reduced apoptosis, and increased CK7 expression. It significantly enhanced HTR-8/SVneo cell viability and migration. Echinatin also counteracted H2O2-induced ROS production and cell death in HTR-8/SVneo cells. Moreover, it inhibited the expression of proteins within the TLR4-MyD88-NF-κB signaling cascade. Overexpression of TLR4 negated echinatin’s protective effects. Conclusion. Echinatin exerts protective effects against oxidative stress and inflammation in PE by targeting the TLR4-MyD88-NF-κB pathway, suggesting its therapeutic potential for the management of preeclampsia.

N-Acetyl-L-cysteine and aminooxyacetic acid differentially modulate toxicity of the trichloroethylene metabolite S-(1,2-dichlorovinyl)-L-cysteine in human placental villous trophoblast BeWo cells

Trichloroethylene (TCE) is a known human carcinogen with toxicity attributed to its metabolism. S-(1,2-Dichlorovinyl)-L-cysteine (DCVC) is a metabolite of TCE formed downstream in TCE glutathione (GSH) conjugation and is upstream of several toxic metabolites. Despite knowledge that DCVC stimulates reactive oxygen species (ROS) generation and apoptosis in placental cells, the extent to which these outcomes are attributable to DCVC metabolism is unknown. The current study used N-acetyl-L-cysteine (NAC) at 5 mM and aminooxyacetic acid (AOAA) at 1 mM as pharmacological modifiers of DCVC metabolism to investigate DCVC toxicity at concentrations of 5–50 µM in the human placental trophoblast BeWo cell model capable of forskolin-stimulated syncytialization. Exposures of unsyncytialized BeWo cells, BeWo cells undergoing syncytialization, and syncytialized BeWo cells were studied. NAC pre/co-treatment with DCVC either failed to inhibit or exacerbated DCVC-induced H2O2 abundance, PRDX2 mRNA expression, and BCL2 mRNA expression. Although NAC increased mRNA expression of CYP3A4, which would be consistent with increased generation of the toxic metabolite N-acetyl-DCVC sulfoxide (NAcDCVCS), a CYP3A4 inhibitor ketoconazole did not significantly alter BeWo cell responses. Moreover, AOAA failed to inhibit cysteine conjugate β-lyase (CCBL), which bioactivates DCVC, and did not affect the percentage of nuclei condensed or fragmented, a measure of apoptosis, in all BeWo cell models. However, syncytialized cells had higher CCBL activity compared to unsyncytialized cells, suggesting that the former may be more sensitive to DCVC toxicity. Together, although neither NAC nor AOAA mitigated DCVC toxicity, differences in CCBL activity and potentially CYP3A4 expression dictated the differential toxicity derived from DCVC.

Fetal Growth Retardation is Associated with High Apoptotic Cells and Low VEGF Expression in Placenta of Malarial Pregnant Mice.

During pregnancy, pregnant women are susceptible to malaria, contributing significantly to maternal and infant mortality. This research was conducted to study the effect of Plasmodium berghei infection in pregnant mice on fetal growth retardation through placental cell apoptosis and the change of local vascularization. Eighteen pregnant Balb/c strain mice resulting from simultanously mating were divided into two groups those were nine pregnant mice used as non infected group and nine pregnant mice infected with Plasmodium berghei on day 9th post mating used as infected group respectively. On day 15th of post mating, all of the pregnant mice were killed. Fetal weights were measured using analytic balance. Apoptosis of placental cells and VEGF expression in the placental tissue were measured using immunohistochemistry. Result showed that there was sequestration of parasite-infected red blood cells (PRBCs) in intervillous space. Statistical analysis showed that the fetal weights in infected pregnant mice group was significantly lower than non infected one (p = 0.01), and the placental cell apoptosis in placental tissue of infected pregnant mice was significantly higher than the non infected one (p=0.00).There was also a significant difference on VEGF expression between infected group and non infected group (p= 0,00). Plasmodium berghei infection in pregnant Balb/c mice can cause fetal growth retardation due to high of placental cell apoptosis and low VEGF expression.

Nobiletin Inhibits Hypoxia-Induced Placental Damage via Modulating P53 Signaling Pathway.

In this study, we aimed to evaluate the effect of Nobiletin (NOB) on the placenta of Sprague–Dawley (SD) rats that had undergone reduced uterine perfusion pressure (RUPP) surgery and to evaluate the safety of NOB intervention during pregnancy. The results showed that NOB alleviated placental hypoxia, attenuated placental cell apoptosis, and inhibited placental damage in RUPP rats. No side effect of NOB intervention during pregnancy was observed. BeWo cell lines with P53 knockdown were then constructed using lentiviral transfection, and the P53 signaling pathway was found to be essential for NOB to reduce hypoxia-induced apoptosis of the BeWo cell lines. In summary, NOB attenuated hypoxia-induced placental damage by regulating the P53 signaling pathway, and those findings may contribute some insights into the role of NOB in placental development and the prevention of placental-related diseases.

Porcine reproductive and respiratory syndrome virus induces tight junction barrier dysfunction and cell death in porcine glandular endometrial epithelial cells

Reproductive failure caused by porcine reproductive and respiratory syndrome virus (PRRSV) is characterized by embryonic death and weak-born piglets and is associated with placental cell apoptosis and impairment of endometrial integrity. Here, we aimed to determine whether endometrial epithelial barrier function and viability were altered following PRRSV type 1 or type 2 infection. PRRSV inoculation was examined at the apical or basolateral side of porcine glandular endometrial epithelial cell cultures isolated from 4- to 6-month-old PRRSV-free herd gilts (n = 7 pigs). On the apical side, four days postinfection (4 dpi) with type 2 PRRSV, transepithelial electrical resistance decreased by 31% ± 5%, and paracellular permeability to fluorescein isothiocyanate-dextran (4 kDa) increased by 10-fold as compared with the mock and type 1 infection. Real-time polymerase chain reaction results revealed that both PRRSV types upregulated the mRNA expression of the barrier builder tight junction protein (TJ) Cldn5, but downregulated pore-forming TJ Cldn7. Additionally, the expression of other TJ genes, i.e., Cldn3 and Cldn8, was differentially increased by PRRSV type 1 and that of zonula occludens-1 was increased by PRRSV type 2. MTT assays indicated an increase in porcine glandular endometrial epithelial cell culture at 2–6 dpi following type 2 infection. Analysis of apoptosis using Annexin/propidium iodide staining combined with flow cytometry showed that the percentage of viable cells decreased, accompanied by a significantly higher dead cell population following PRRSV type 2 infection at 2–4 dpi. PRRSV type 1 infection also induced dead cells (>4%) at 2 dpi; however, the cell population recovered at 4 dpi. In conclusion, PRRSV type 2 infection caused more severe TJ barrier dysfunction and reduced cell viability compared with PRRSV type 1 infection in the porcine endometrium. Impairment in the membrane integrity of the maternal glandular endometrium may be the underlying mechanism of PRRSV-induced reproductive failure in pregnant sows.

Gestational exposure to BDE-209 induces placental injury via the endoplasmic reticulum stress-mediated PERK/ATF4/CHOP signaling pathway

Several epidemiological studies have reported significant associations between prenatal polybrominated diphenyl ethers (PBDEs) exposure and adverse birth outcomes. Placental injury is thought to mediate these associations. However, few study has investigated the adverse effects of PBDEs exposure on placental growth and development. We examined the impacts of gestational exposure to BDE-209, the most abundant PBDE conger detected in human samples, on placental structure and function, and its model of action in vivo and in vitro. Pregnant mice were exposed to 0, 2, 20, 200 mg/kg/day of BDE-209 by gavages from gestational day (GD) 0 to GD18. Results showed that gestational BDE-209 exposure significantly reduced placental weight, impaired placental vascular development and induced placental cell apoptosis. In addition, gestational BDE-209 exposure impaired placental transport and endocrine function as demonstrated by markedly downregulated expression of Glut1, Znt1, Pgf and Igf2 in BDE-209-treated placentas. Mechanistically, gestational exposure to BDE-209 upregulated the expression of GRP78, and 3 downstream proteins (p-eIF2α, ATF4 and CHOP) of the PERK signaling, suggesting the activation of endoplasmic reticulum (ER) stress and PERK signaling pathway in mouse placentas. Further in vitro study showed that PERK siRNA pretreatment markedly reversed BDE-209-induced cell apoptosis in human JEG-3 cells. Collectively, our results suggest that the activation of the ER stress-mediated PERK/ATF4/CHOP signaling pathway played a role in BDE-209-induced placental injury. Our findings provide new insight into the mechanisms of BDE-209 induced reproductive and developmental toxicity.

Pregnant Women and Endocrine Disruptors: Role of P2X7 Receptor and Mitochondrial Alterations in Placental Cell Disorders.

In pregnant women, the lungs, skin and placenta are exposed daily to endocrine-disrupting chemicals (EDCs). EDCs induce multiple adverse effects, not only on endocrine organs, but also on non-endocrine organs, with the P2X7 cell death receptor being potentially the common key element. Our objective was first to investigate mechanisms of EDCs toxicity in both endocrine and non-endocrine cells through P2X7 receptor activation, and second, to compare the level of activation in lung, skin and placental cells. In addition, apoptosis in placental cells was studied because the placenta is the most exposed organ to EDCs and has essential endocrine functions. A total of nine EDCs were evaluated on three human cell models. We observed that the P2X7 receptor was not activated by EDCs in lung non-endocrine cells but was activated in skin and placenta cells, with the highest activation in placenta cells. P2X7 receptor activation and apoptosis are pathways shared by all tested EDCs in endocrine placental cells. P2X7 receptor activation along with apoptosis induction could be key elements in understanding endocrine placental and skin disorders induced by EDCs.

Roles of insulin-like growth factor II in regulating female reproductive physiology.

The number of growth factors involved in female fertility has been extensively studied, but reluctance to add essential growth factors in culture media has limited progress in optimizing embryonic growth and implantation outcomes, a situation that has ultimately led to reduced pregnancy outcomes. Insulin-like growth factor II (IGF-II) is the most intricately regulated of all known reproduction-related growth factors characterized to date, and is perhaps the predominant growth factor in human ovarian follicles. This review aims to concisely summarize what is known about the role of IGF-II in follicular development, oocyte maturation, embryonic development, implantation success, placentation, fetal growth, and in reducing placental cell apoptosis, as well as present strategies that use growth factors in culture systems to improve the developmental potential of oocytes and embryos in different species. Synthesizing the present knowledge about the physiological roles of IGF-II in follicular development, oocyte maturation, and early embryonic development should, on the one hand, deepen our overall understanding of the potential beneficial effects of growth factors in female reproduction and on the other hand support development (optimization) of improved outcomes for assisted reproductive technologies.

Synthetic cannabinoids JWH-018, JWH-122, UR-144 and the phytocannabinoid THC activate apoptosis in placental cells

The increasing use of synthetic cannabinoids (SCBs) in recreational settings is becoming a new paradigm of drug abuse. Although SCBs effects mimic those of the Cannabis sativa plant, these drugs are frequently more potent and hazardous. It is known that endocannabinoid signalling plays a crucial role in diverse reproductive events such as placental development. Moreover, the negative impact of the phytocannabinoid Δ9-tetrahydrocannabinol (THC) in pregnancy outcome, leading to prematurity, intrauterine growth restriction and low birth weight is well recognized, which makes women of childbearing age a sensitive group to developmental adverse effects of cannabinoids. Placental trophoblast turnover relies on regulated processes of proliferation and apoptosis for normal placental development. Here, we explored the impact of the SCBs JWH-018, JWH-122 and UR-144 and of the phytocannabinoid THC in BeWo cell line, a human placental cytotrophoblast cell model. All the cannabinoids caused a significant decrease in cell viability without LDH release, though this effect was only detected for the highest concentrations of THC. Moreover, a cell cycle arrest at the G2/M phase was also observed. JWH-018 and JWH-122 increased reactive oxygen species (ROS) production and THC, UR-144 and JWH-122 caused loss of mitochondrial membrane potential. All the compounds were able to induce caspase-9 activation. The involvement of apoptotic pathways was further confirmed through the significant increase in caspase -3/-7 activities. For UR-144, this effect was reversed by the CB1 antagonist AM281, for JWH-018 and THC this effect was mediated by both cannabinoid receptors CB1 and CB2 while for JWH-122 it was cannabinoid receptor-independent. This work demonstrates that THC and SCBs are able to induce apoptotic cell death. Although they may act through different mechanisms and potencies, the studied cannabinoids have the potential to disrupt gestational fundamental events.

Global miRNA, lncRNA, and mRNA Transcriptome Profiling of Endometrial Epithelial Cells Reveals Genes Related to Porcine Reproductive Failure Caused by Porcine Reproductive and Respiratory Syndrome Virus.

Porcine reproductive and respiratory syndrome virus (PRRSV) can cause respiratory disease and reproductive failure in pregnant pigs. Previous transcriptome analyses in susceptive cells have mainly concentrated on pulmonary alveolar macrophages (PAM) and Marc-145 cells, and on the respiratory system. Some studies reported that apoptosis of placental cells and pig endometrial epithelial cells (PECs) is an obvious sign linked to reproductive failure in pregnant sows, but the mechanism is still unknown. In this study, Sn-positive PECs were isolated and apoptosis rates were assessed by flow cytometry. PRRSV-infected PECs exhibited apoptosis, indicative of their susceptibility to PRRSV. Subsequently, the whole transcriptome was compared between mock- and PRRSV-infected PECs and 54 differentially expressed microRNAs (DEmiRNAs), 104 differentially expressed genes (DEGs), 22 differentially expressed lncRNAs (DElncRNAs), and 109 isoforms were obtained, which were mainly enriched in apoptosis, necroptosis, and p53 signal pathways. Integration analysis of DEmiRNA and DEG profiles revealed two microRNAs (ssc-miR-339-5p and ssc-miR-181d-5p) and five genes (SLA-DQB1, THBS1, SLC3A1, ZFP37, and LOC100517161) participating in the apoptosis signal, of which THBS1 and SLC3A1 were mainly linked to the p53 pathway. Integration analysis of DEGs with DElncRNA profiles identified genes involved in apoptosis signal pathway are regulated by LTCONS_00010766 and LTCONS_00045988. Pathway enrichment revealed that the phagosome and p53 pathways are the two main signals causing apoptosis of PECs, and functional analysis revealed a role of miR-339-5p in regulating apoptosis of PECs after PRRSV inoculation.

MATRIX METALOPROTEINASE-2 AND PLACENTARY DYSFUNCTION DEVELOPMENT IN PREGNANCY WITH PERINATAL INFECTIONS

The search for a statistically significant link between sFasL and their potential regulators MMP-2 is necessary to optimize the tactics of managing and treating pregnant women with perinatal infections. To determine the level of MMP-2 in pregnant with perinatal infections and its role in the development of placental dysfunction. The study involved examination of 230 pregnant, who were divided into 3 groups (60 people each): Group I with viral (CMV, HSV-1,2,6 types), Group II with bacterial (chlamydia, ureaplasma, mycoplasma) and Group III with mixed infection. Group IV was the control one, and included 50 pregnant with a physiological course of pregnancy. The study implied determination of serum levels of MMP-2 and sFasL, the level of caspase-3 in the placenta, ultrasound was performed by the MINDRAY M7 (China) scanner. The data obtained were statistically processed using the STATISTICA software. Pregnant women with perinatal infection were found to have a significant increase in sFasL and caspase-3 levels in all the studied groups as compared to corresponding values in the control group (Kruskal-Wallis test, p <0.001). In all groups of pregnant women with perinatal infection the level of MMP-2 in serum was elevated with respect to control values approximately 3-4 times (Kruskal-Wallis test, p <0.05). According to ultrasound data, hypoplasia of placenta was observed in (46.6 ± 6.4)% of cases in Group І and in (30 ± 6.4)% in Group ІІІ. In Groups II and III, placental hyperplasia was detected in (20 ± 5.2)% and (26 ± 5.7)% of cases, respectively. The findings showed that secondary to the impact of perinatal infection among a number of indices in the peripheral blood of pregnant women, a significant role is played by an increase in levels of MMP-2 and sFasL. These indices reflect and determine the induction of apoptotic response from the placenta in this category of pregnant women. The revealed increase in caspase-3 level means that pregnant women with perinatal infections undergo caspase cascade of apoptosis in placental cells. Thus, the obtained results indicate that pregnant women with perinatal infections develop an increase in the level of MMP-2 and activation of the Fas-dependent signaling pathway of programmed cell death, which leads to the launch of a caspase cascade of apoptosis in placental cells. An increase in the loss of placental cells due to apoptosis may be one of the key factors triggering the development of placental dysfunction and, as a consequence, unfavorable conditions for fetal development.

Upregulation of DAPK2 ameliorates oxidative damage and apoptosis of placental cells in hypertensive disorder complicating pregnancy by suppressing human placental microvascular endothelial cell autophagy through the mTOR signaling pathway

Death-associated protein kinase 2 (DAPK2) has indicated functional roles in cellular processes, including survival, apoptosis, and autophagy. This study is aimed to identify the effect of DAPK2 on oxidative damage and apoptosis of placental cells in hypertensive disorder complicating pregnancy (HDCP) through mTOR pathway. Microarray-based gene expression analysis was performed to predict the differentially expressed genes related to HDCP. To investigate the specific mechanism of DAPK2 in HDCP cells, placental microvascular endothelial cells were treated with mimic or siRNA of DAPK2 and mTOR to detect the expression of related genes, cell autophagy and apoptosis and oxidative damage. Finally, rats were modeled with HDCP to verify the cell experiment results. DAPK2 was downregulated in HDCP, and could activate mTOR. Besides, DAPK2 overexpression led to decreases in autophagy in HPVECs as well as apoptosis and oxidative damage in placental cells indicated by a substantial decrease in Beclin-1, LC3 II/LC3 I and Bax along with an increase in Bcl-2, 4EBP1 and p70S6K. It also ameliorates blood pressure elevation in HDCP rats. The study defined remission effect of DAPK2 on placental cell oxidative damage and apoptosis in HDCP via mTOR activation. Together, DAPK2 regulating mTOR pathway presents a promising therapy for HDCP treatment.

Gestational 1-nitropyrene exposure causes fetal growth restriction through disturbing placental vascularity and proliferation

1-Nitropyrene (1-NP) is a widely distributed pollutant in the environment and is best known for its mutagenicity and carcinogenicity. In this study, we evaluated the effects of 1-NP exposure in different gestational stages on the pregnant outcomes. Pregnant mice were administered with 1-NP by gavage daily in early (GD1-GD6), middle (GD7-GD12) or late pregnancy (GD13-GD17), respectively. We found that gestational 1-NP exposure had no effect on implantation sites per litter, preterm delivery and fetal death. Interestingly, mice exposed to 1-NP in late pregnancy showed a significant reduction in fetal weight and crown-rump length. Correspondingly, placental weight and diameter were markedly reduced in dams exposed to 1-NP in late pregnancy. Additional experiment showed maternal 1-NP exposure in late pregnancy reduced blood sinusoid area of placental labyrinthine region in a dose-dependent manner. Although gestational 1-NP exposure had little effect on placental cell apoptosis, as determined by the TUNEL assay, the rate of Ki67-positive cell, a marker of cell proliferation, was reduced in placental labyrinthine region of mice exposed to 1-NP in late pregnancy. These findings provide evidence that gestational 1-NP exposure induces fetal growth restriction in a stage-dependent manner. Placenta is a toxic target in the process of 1-NP-induced fetal growth restriction.

Leptin action in normal and pathological pregnancies.

Leptin is now considered an important signalling molecule of the reproductive system, as it regulates the production of gonadotrophins, the blastocyst formation and implantation, the normal placentation, as well as the foeto‐placental communication. Leptin is a peptide hormone secreted mainly by adipose tissue, and the placenta is the second leptin‐producing tissue in humans. Placental leptin is an important cytokine which regulates placental functions in an autocrine or paracrine manner. Leptin seems to play a crucial role during the first stages of pregnancy as it modulates critical processes such as proliferation, protein synthesis, invasion and apoptosis in placental cells. Furthermore, deregulation of leptin levels has been correlated with the pathogenesis of various disorders associated with reproduction and gestation, including polycystic ovary syndrome, recurrent miscarriage, gestational diabetes mellitus, pre‐eclampsia and intrauterine growth restriction. Due to the relevant incidence of the mentioned diseases and the importance of leptin, we decided to review the latest information available about leptin action in normal and pathological pregnancies to support the idea of leptin as an important factor and/or predictor of diverse disorders associated with reproduction and pregnancy.

Effect of heat exposure in the second trimester of pregnancy on intrauterine growth of fatal rat and the expression of HSP70, Bax and Bcl-2 of placenta

To investigate the effect of heat exposure during the second week of pregnancy on placental development and intrauterine growth of fetal rats. 24 pregnant rats were either exposed or not to a temperature of 35∓1 degrees celsius; during the second week of pregnancy. The body weight gain of the pregnant rats was measured regularly, and in late pregnancy, the pregnant rats were dissected and the number, weight, length, tail length, appearance of the offspring rats, number of live and still births, and the placental weight were recorded. The expressions of HSP70, Bax and Bcl-2 in the placenta were determined. Compared with the control group, the pregnant rats in heat exposure group had significantly lower body weight at the end of pregnancy and gestational weight gain, and the body weight, body length and tail length of the offspring rats were also significantly lower or smaller (P<0.05). The placental weight was comparable between the two groups. The placental expressions of HSP70,Bax,and Bcl-2 were significantly higher in the heat exposure group than in the control group (P<0.05). Heat exposure during the second trimester of pregnancy has adverse effects on placental development and intrauterine growth of the fetal rats by inducing heat shock response of placental tissue and apoptosis of the placental cells.

Adiponectin Inhibits Nutrient Transporters and Promotes Apoptosis in Human Villous Cytotrophoblasts: Involvement in the Control of Fetal Growth.

The placenta exchanges nutrients between the mother and the fetus and requires a constant abundant energy supply. Adiponectin (a cytokine produced primarily by adipose tissue) controls glucose and lipid homeostasis. It is well-known that maternal serum adiponectin levels are inversely related to birth weight, suggesting that adiponectin has a negative effect on fetal growth. This effect appears to be related to the control of nutrient transporters in human placenta. However, the underlying molecular mechanisms have not yet been characterized. In the present work, we studied adiponectin's direct effect on human primary cytotrophoblasts from first-trimester placenta. Our result showed that in placental cells, adiponectin 1) inhibits the expression of the major glucose transporters (GLUT1 and GLUT12) and sodium-coupled neutral amino acid transporters (SNAT1, SNAT2, and SNAT4), 2) enhances total ATP production but decreases lactate production, 3) inhibits mitochondrial biogenesis and function, and 4) stimulates cell death by enhancing the expression of the pro-apoptotic B-cell lymphoma-2 (BCL-2)-associated X protein (BAX) and tumor protein P53 (TP53) gene expression and inducing the caspase activity. Small-interfering RNA mediating the down-regulation of adiponectin receptors (ADIPOR1 and ADIPOR2) was used to demonstrate that adiponectin effects on placental nutrient transport and apoptosis seemed to be essentially mediated by these specific receptors. Taken as a whole, these results strongly suggest that adiponectin regulates human placental function by limiting nutrient transporter expression and inducing apoptosis. These findings may help us to better understand adiponectin's role in placental pathologies such as intrauterine growth restriction, which is characterized by fetal weight loss and drastic apoptosis of placental cells.

Dexamethasone Downregulates SLC7A5 Expression and Promotes Cell Cycle Arrest, Autophagy and Apoptosis in BeWo Cells.

Synthetic glucocorticoids (GCs) such as dexamethasone (Dex) are widely given to pregnant women to induce maturation and improve viability of preterm infants. Despite the beneficial effects, synthetic GCs have adverse effects on placental growth and nutrient transport system. However, the molecular mechanisms involved in these events remain unknown. Here we use a human placental choriocarcinoma cell line (BeWo) as model to explore the pathway linking amino acids transport with cell viability under Dex challenge. BeWo cells treated with Dex (100 nM) for 24 h demonstrated G1/S cell cycle arrest together with enhanced autophagy and apoptosis. Concurrently, the amino acid carrier SLC7A5 was down-regulated in association with impaired cellular amino acids uptake and inhibition of mammalian target of rapamycin (mTOR) signaling. Similar cellular responses were observed in BeWo cells treated with BCH, a classical System L inhibitor which inactivates SLC7A5. The glucocorticoid receptor (GR) antagonist RU486 was able to diminish Dex-induced translocation of GR into nucleus and to abolish these effects. Furthermore, Dex treatment significantly promoted the binding of GR to the proximal promoter sequence of SLC7A5 gene. Taken together, our results show that Dex downregulates SLC7A5 expression via GR-mediated transrepression. The impaired amino acids uptake leads to inhibition of mTOR signaling which in turn causes inhibited proliferation and enhanced autophagy and apoptosis in BeWo cells. These findings indicate that SLC7A5 mediates the effect of Dex on cell viability, thus providing a novel molecular target for the prevention and treatment of Dex-induced cell cycle arrest and apoptosis in placental cells.

Relationships Between Cell-Free DNA and Serum Analytes in the First and Second Trimesters of Pregnancy

To assess the relationship between first- and second-trimester cell-free DNA levels and maternal serum screening markers. First- and second-trimester residual maternal serum samples from 50 women were obtained. First-trimester (pregnancy-associated plasma protein A and beta-hCG) and second-trimester serum analytes (beta-hCG, alpha-fetoprotein, unconjugated estriol, and inhibin A) had been measured at the time of sample receipt. All fetuses were male as confirmed by birth records. Cell-free DNA was extracted and measured by real-time quantitative polymerase chain reaction amplification using glyceraldehyde phosphate dehydrogenase and DYS1 as markers of total DNA and fetal DNA, respectively. Determination of linear associations between first- and second-trimester serum markers and cell-free DNA levels using Pearson correlations was performed. Statistically significant correlations between first-trimester pregnancy-associated plasma protein A multiples of the median and both total (r=0.36, P=.016) and fetal (r=0.41, P=.006) DNA in the first trimester were observed. There were no significant correlations between first-trimester serum human chorionic gonadotropin or any second-trimester serum marker with DNA levels. Correlation between serum pregnancy-associated plasma protein A and first-trimester circulating cell-free fetal and total DNA levels is a novel finding. Pregnancy-associated plasma protein A is a glycoprotein of placental origin, and its correlation to cell-free fetal DNA in maternal serum suggests a common tissue origin through apoptosis of placental cells. However, because pregnancy-associated plasma protein A and cell-free DNA were only marginally correlated and cell-free DNA can be reliably detected in the first trimester, the addition of cell-free DNA to serum screening strategies may be helpful in predicting adverse pregnancy outcome. II.

Evidence for Participation of Uterine Natural Killer Cells in the Mechanisms Responsible for Spontaneous Preterm Labor and Delivery

Objective The purpose of this study was to determine in a mouse model whether uterine natural killer (uNK) cell cytotoxic activation induces infection/inflammation-associated preterm labor and delivery. Study Design Wild type or interleukin (IL)-10 –/– mice were injected intraperitoneally with lipopolysaccharide on gestational day 14. Mice were either killed for collection of uteroplacental tissue, spleen, and serum or allowed to deliver. Uteroplacental tissue was used for histology and characterization of uNK cells. Results Low-dose lipopolysaccharide treatment triggered preterm labor and delivery in IL-10 –/– , but not wild type mice, in a manner independent of progesterone levels. Preterm labor and delivery in IL-10 –/– mice was associated with an increased number and placental infiltration of cytotoxic uNK cells and placental cell death. Depletion of NK cells or tumor necrosis factor (TNF)-α neutralization in these mice restored term delivery. Furthermore, TNF-α neutralization prevented uNK cell infiltration and placental cell apoptosis. Conclusion The uNK cell-TNF-α–IL-10 axis plays an important role in the genesis of infection/inflammation-induced preterm labor/delivery.