B(a)P induces ovarian granulosa cell apoptosis via TRAF2-NFκB-Caspase1 axis during early pregnancy.

Benzo(a)pyrene [B(a)P] is an environmental endocrine disruptor with reproductive toxicity. The corpus luteum (CL) of the ovary plays an important role in embryo implantation and pregnancy maintenance. Our previous studies have shown that B(a)P exposure affects embryo implantation and endometrial decidualization in mouse, but its effects and mechanisms on CL function remain unclear. In this study, we explore the mechanism of ovarian toxicity of B(a)P using a pregnant mouse model and an in vitro model of human ovarian granulosa cells (GCs) KGN. Pregnant mice were gavaged with corn oil or 0.2 mg/kg.bw B(a)P from pregnant day 1 (D1) to D7, while KGN cells were treated with DMSO, 1.0IU/mL hCG, or 1.0IU/mL hCG plus benzo(a)pyrene-7,8-dihydrodiol-9,10-epoxide (BPDE), a B(a)P metabolite. Our findings revealed that B(a)P exposure damaged embryo implantation and reduced estrogen and progesterone levels in early pregnant mice. Additionally, in vitro, BPDE impaired luteinization in KGN cells. We observed that B(a)P/BPDE promoted oxidative stress (OS) and inflammation, leading to apoptosis rather than pyroptosis in ovaries and luteinized KGN cells. This apoptotic response was mediated by the activation of inflammatory Caspase1 through the cleavage of BID. Furthermore, B(a)P/BPDE inhibited TRAF2 expression and suppressed NFκB signaling pathway activation. The administration of VX-765 to inhibit the Caspase1 activation, over-expression of TRAF2 using TRAF2-pcDNA3.1 (+) plasmid, and BetA-induced activation of NFκB signaling pathway successfully alleviated BPDE-induced apoptosis and cellular dysfunction in luteinized KGN cells. These findings were further confirmed in the KGN cell treated with H2O2 and NAC. In conclusion, this study elucidated that B(a)P/BPDE induces apoptosis rather than pyroptosis in GCs via TRAF2-NFκB-Caspase1 during early pregnancy, and highlighting OS as the primary contributor to B(a)P/BPDE-induced ovarian toxicity. Our results unveil a novel role of TRAF2-NFκB-Caspase1 in B(a)P-induced apoptosis and broaden the understanding of mechanisms underlying unexplained luteal phase deficiency.

Subacute exposure to DEHP leads to impairing decidualization process and exacerbating the risk of early pregnancy miscar-riage in mice. / 孕早期增塑剂DEHPäºšæ€¥æ€§æš´éœ²å½±å“èœ•è†œååº”å¹¶å¢žåŠ æµäº§é£Žé™©.

OBJECTIVES: To investigate the effect of subacute exposure of Di (2-ethylhexyl) phthalate (DEHP) on endometrial decidualization in mice. METHODS: CD1 mice were orally administrated with 300 mg·kg－1·d－1 (low-dose group), 1000 mg·kg－1·d－1 (medium-dose group), or 3000 mg·kg－1·d－1 DEHP (1/10 LD50, high-dose group) for 28 days, respectively. The early natural pregnancy model and artificially induced decidualization model were established, and the uterine tissues were collected on D7 of natural pregnancy and D8 of artificially induced decidualization, respectively. The effects of subacute exposure to DEHP on the decidualization of mice were detected by HE staining, Masson staining, TUNEL staining, and Western blotting, respectively. A model of spontaneous abortion was constructed in mice after subacute exposure to 300 mg·kg-1·d-1 DEHP, and the effect of impaired decidualization on pregnancy was investigated by observing the pregnancy outcome on the 10th day of gestation. RESULTS: Compared with the control group, the conception rate was significantly lower in the high-dose DEHP subacute exposure group. HE staining showed that, compared with the control group, the decidual stromal cells in the low- and medium-dose exposure groups were disorganized, the nuclei of the cells were irregular, the cytoplasmic staining was uneven, and the number of polymorphonuclear cells was significantly reduced. Masson staining showed that compared with the control group, the collagen fibers in the decidua region of the DEHP low-dose group and the medium-dose group were more distributed, more abundant and more disorderly. TUNEL staining showed increased apoptosis in the decidua area compared to the control group. Western blotting showed that the expression of BMP2, a marker molecule for endometrial decidualization, was significantly reduced. The abortion rate and embryo resorption rate were significantly higher, and the number of embryos, uterine wet weight, uterine area and placenta wet weight were significantly lower in mice exposed to 300 mg·kg－1·d－1 DEHP than in control mice stimulated by mifepristone abortifacient drug. CONCLUSIONS: Subacute exposure to DEHP leads to impaired endometrial decidualization during early pregnancy and exacerbates the risk of adverse pregnant outcomes in mice.

Uterine deficiency of Dnmt3b impairs decidualization and causes consequent embryo implantation defects.

Uterine deficiency of Dnmt3b impairs decidualization and consequent embryo implantation defects. Recent advances in molecular technologies have allowed the unprecedented mapping of epigenetic modifications during embryo implantation. DNA methyltransferase 3a (DNMT3A) and DNMT3B are responsible for establishing DNA methylation patterns produced through their de novo-type DNA methylation activity in implantation stage embryos and during germ cell differentiation. It was reported that conditional knockout of Dnmt3a in the uterus does not markedly affect endometrial function during embryo implantation, but the tissue-specific functions of Dnmt3b in the endometrium during embryo implantation remain poorly understood to investigate the role of Dnmt3b during peri-implantation period. Here, we generated Dnmt3b conditional knockout (Dnmt3bd/d) female mice using progesterone receptor-Cre mice and examined the role of Dnmt3b during embryo implantation. Dnmt3bd/d female mice exhibited compromised fertility, which was associated with defective decidualization, but not endometrial receptivity. Furthermore, results showed loss of Dnmt3b did not lead to altered genomic methylation patterns of the decidual endometrium during early pregnancy. Transcriptome sequencing analysis of uteri from day 6 pregnant mice identified phosphoglycerate kinase 1 (Pgk1) as one of the most variable genes in Dnmt3bd/d decidual endometrium. Potential roles of PGK1 in the decidualization process during early pregnancy were confirmed. Lastly, the compromised decidualization upon the downregulation of Dnmt3b could be reversed by overexpression of Pgk1. Collectively, our findings indicate that uterine deficiency of Dnmt3b impairs decidualization and consequent embryo implantation defects.

Decidual derived exosomal miR-99a-5p targets Ppp2r5a to inhibit trophoblast invasion in response to CeO2NPs exposure.

BACKGROUND: The biological effects of cerium dioxide nanoparticles (CeO2NPs), a novel material in the biomedical field, have attracted widespread attention. Our previous study confirmed that exposure to CeO2NPs during pregnancy led to abnormal trophoblast invasion during early placental development, thereby impairing placental development. The potential mechanisms may be related to low-quality decidualization triggered by CeO2NPs exposure, such as an imbalance in trophoblast invasion regulators secreted by decidual cells. However, the intermediate link mediating the "dialogue" between decidual cells and trophoblasts during this process remains unclear. As an important connection between cells, exosomes participate in the "dialogue" between endometrial cells and trophoblasts. Exosomes transfer bioactive microRNA into target cells, which can target and regulate the level of mRNA in target cells. RESULTS: Here, we constructed a mice primary uterine stromal cell-induced decidualization model in vitro, and detected the effect of CeO2NPs exposure on the expression of decidual-derived exosomal miRNAs by high-throughput sequencing. Bioinformatics analysis and dual-luciferase reporter assays were performed to identify target genes of the screened key miRNAs in regulating trophoblast invasion. Finally, the role of the screened miRNAs and their target genes in regulating trophoblast (HTR-8/SVneo cells) invasion was confirmed. The results showed that CeO2NPs exposure inhibited trophoblast invasion by promoting miR-99a-5p expression in decidual-derived exosomes, and Ppp2r5a is a potential target gene for miR-99a-5p to inhibit trophoblast invasion. CONCLUSIONS: This study revealed the molecular mechanism by which CeO2NPs exposure inhibits trophoblast invasion from the perspective of decidual derived exosomal miRNAs. These results will provide an experimental basis for screening potential therapeutic targets for the negative biological effects of CeO2NPs exposure and new ideas for studying the mechanism of damage to trophoblast cells at the decidual-foetal interface by harmful environmental or occupational factors.

MicroRNA-27a, downregulated in human obesity, exerts an antiapoptotic function in adipocytes.

Adipocyte apoptosis is a key initial event that contributes to macrophage infiltration into adipose tissue (AT) and thus triggers AT inflammation in obesity. MicroRNA-27a (miR-27a) was shown to mediate the pathological processes of many metabolic disorders; however, whether miR-27a is involved in adipocyte apoptosis of obese AT remains unknown. The present study aimed to investigate the alteration of miR-27a in obese individuals and its antiapoptotic function in adipocytes. In vivo, serum samples and omental adipose tissue from humans as well as epididymal fat pads from mice were collected to detect miR-27a expression. In vitro, 3T3-L1 preadipocytes and mature adipocytes were treated with TNF-α to induce apoptosis and transfected with a mimic for overexpressing miR-27a-3p. The results showed that miR-27a was markedly decreased in the serum and AT of obese human patients and in the AT of high-fat diet-fed mice. Regression analyses revealed that the serum level of miR-27a was correlated with metabolic parameters in human obesity. Notably, TNF-α induced cell apoptosis in both preadipocytes and mature adipocytes, as evidenced by the upregulation of cleaved caspase 3 and cleaved caspase 8 and the ratio of Bax to Bcl-2, while these effects were partly diminished by miR-27a overexpression. In addition, TUNEL and Hoechst 33258 staining verified that miR-27a overexpression markedly inhibited the apoptosis of adipocytes under TNF-α stimulation. Thus, miR-27a was downregulated in the AT of obese subjects with proapoptotic status, and overexpression of miR-27a exerted an antiapoptotic effect on preadipocytes, providing a novel potential target for preventing AT dysfunction.

Exposure to Benzo(a)pyrene promotes proliferation and inhibits differentiation of stromal cells in mice during decidualization.

The environmental pollutant Benzo(a)pyrene (BaP) has an adverse effect on the reproductive performance of mammals. We previously showed that BaP treatment during early pregnancy damages endometrial morphology and impairs embryo implantation. Endometrial decidualization at the implantation site (IS) after embryo implantation is crucial for pregnancy maintenance and placental development. The balance between proliferation and differentiation in endometrial stromal cells (ESCs) is a crucial event of decidualization, which is regulated by the cell cycle. Here, we report that abnormal decidualization caused by BaP is associated with cell cycle disturbance of stromal cells. The mice in the treatment group were gavaged with 0.2 mg/kg/day BaP from day 1-8 of pregnancy, while those in control were gavaged with corn oil in parallel. BaP damaged the decidualization of ESCs and reduced the number of polyploid cells. Meanwhile, BaP up-regulated the expression of Ki67 and PCNA, affecting the differentiation of stromal cells. The cell cycle progression analysis during decidualization in vivo and in vitro showed that BaP induced polyploid cells deficiency with enhanced expressions of CyclinA(E)/CDK2, CyclinD/CDK4 and CyclinB/CDK1, which promote the transformation of cells from G1 to S phase and simultaneously activate the G2/M phase. The above results indicated that BaP exposure accelerates cell cycle progression, promotes ESC proliferation, inhibits differentiation, and impedes proper decidualization and polyploidy development. Thus, the imbalance of ESC proliferation and differentiation would be an important mechanism for BaP-induced defective decidualization.

Plasticizer DEHP exposure in early pregnancy affects the endometrial decidualization in mice through reducing lncRNA RP24-315D19.10 expression. / 孕早期增塑剂DEHPæš´éœ²é™ä½Žé•¿é“¾éžç¼–ç RNA RP24-315D19.10è¡¨è¾¾å½±å“å­å®«å† è†œèœ•è†œååº”.

OBJECTIVES: To explore the effect of exposure to di (2-ethyl) hexyl phthalate (DEHP) in early pregnancy on endometrial decidualization in mice and its relation with lncRNA RP24-315D19.10. METHODS: Early pregnancy mice were exposed to DEHP (1000 mg·kg－1·d－1) to construct the model. The uterus was collected on day 6 of pregnancy to detect its effect on decidualization by HE staining and immunofluorescence. A decidualization induction model of mouse endometrial stromal cells exposed to DEHP (0.1, 0.5, 2.5, 12.5, 62.5 µmol/L) was constructed. The changes of cell morphology were observed by light microscopy and phalloidin staining, and the expression of decidual reaction related molecular markers were detected by immunofluorescence, realtime RT-PCR and Western blotting. The expression of RP24-315D19.10 in decidua tissue and cells was detected by realtime RT-PCR. Cellular localization of RP24-315D19.10 was determined by lncLocator database and RNA FISH. AnnoLnc2 database was used to predict miRNAs bound to RP24-315D19.10. RESULTS: The number of embryo implantation sites, uterine weight and uterine area were significantly lower in the DEHP exposed group than those in the control group, and the expression of the decidual reaction related molecular markers matrix metalloprotein 9 and homeobox A10 in the DEHP exposure group were also significantly lower than those in the control group (all P<0.05). With the increase of DEHP concentration, the expression of dtprp in decidua cells was gradually decreased. 2.5 µmol/L DEHP exposed stromal cells failed to be fully decidualized in vitro, andphalloidin staining showed abnormal cytoskeleton morphology. The expression levels of homeobox A10, bone morphogenetic protein 2 and proliferating cell nuclear antigen in the DEHP exposure group were significantly lower than those in the control group (all P<0.05). The expression of RP24-315D19.10 in DEHP exposed decidua tissue and cells was significantly reduced (both P<0.05). RP24-315D19.10 is mainly localized in the cytoplasm and RP24-315D19.10 might bind to 45 miRNAs, among them, miR-138-5p, miR-155-5p, miR-183-5p and miR-223-3p were associated with endometrial decidualization. CONCLUSIONS: DEHP exposure in early pregnancy may impair endometrial decidualization, and the damage may be associated with the down-regulation of RP24-315D19.10.

Maternal exposure to CeO2NPs derails placental development through trophoblast dysfunction mediated by excessive autophagy activation.

BACKGROUND: The increasing use of cerium dioxide nanoparticles (CeO2NPs) in biomedical field has attracted substantial attention about their potential risks to human health. Recent studies have shown that nanoparticles can induce placental dysfunction and even fetal abortion, but a more detailed mechanism of nanoparticles affecting placental development remains elusive. RESULTS: Here, we constructed a mouse exposure model with different doses of CeO2NPs (2.5, 4, 5, 7.5, and 10 mg kg-1 day-1, average particle size 3-5 nm), finding that intravenous exposure to pregnant mice with CeO2NPs could cause abnormal placental development. Deposited nanoparticles were able to be observed in the placental trophoblast at doses of 5 and 7.5 mg kg-1 day-1. Diving into molecular mechanisms indicated that CeO2NPs exposure could lead to autophagy activation in placental trophoblast. At the cellular level, exposure to CeO2NPs inhibited the migration and invasion of HTR-8/SVneo and activated the autophagy through mammalian target of rapamycin complex1 (mTORC1) signaling pathway. Furthermore, inhibition of autophagy initiation by 3-Methyladenine (3-MA) partially restored the function of HTR-8/SVneo, while blocking autophagic flow by Chloroquine (CQ) aggravated the functional damage. CONCLUSIONS: Maternal exposure to CeO2NPs impairs placental development through trophoblast dysfunction mediated by excessive autophagy activation. These results suggested that autophagy dysfunction may be a potential mechanism for the impairment of trophoblast by CeO2NPs exposure. As above, our findings provide insights into the toxicity mechanism to the reproductive system induced by rare-earth nanoparticles exposure.

The expression of lincRNA AC027700.1 in mouse decidualization.

Long non-coding RNAs (lncRNAs), which belong to the non-protein-coding RNAs, are greater than 200 nt in length. Although they have been found to play crucial roles in the regulation of cell growth and development, cell metabolism and the development of diseases, they are rarely reported in decidualization. The objective of our study is to explore the expression of lincRNA AC027700.1 in the endometrium of early pregnant mice and its role in decidualization. The expression of AC027700.1 in uterine tissues at implantation sites and inter implantation sites on the 6th day of pregnancy were detected by qRT-PCR. The relative expression of AC027700.1 in an in vivo model of induced decidualization in pseudopregnant mice and in in vitro model of induced decidualization in primary stromal cells and nucleus/cytoplasmic fractions were detected by qRT-PCR. GO and KEGG analysis of downstream target genes were performed by GOseq and KOBAS, respectively. The results show that AC027700.1 expression is significantly increased in tissues at implantation sites on the 6th day of pregnancy and in decidualized endometrial tissues and stromal cells. Furthermore, AC027700.1 localizes in the nuclear fraction and the downstream targeted genes are mainly involved in autophagy, cell cycle and RNA transport pathways. This study revealed that lincRNA AC027700.1 may be involved in decidualization of endometrium in early pregnancy, but the specific role and regulatory mechanism remain to be further studied.

Impairment of endometrial decidual reaction in early pregnant mice fed with high fat diet.

OBJECTIVE: To investigate the effect of obesity induced by high fat diet on decidual reaction of endometrium in mice, and the effect of high fat treatment on decidual reaction of endometrial stromal cells. METHODS: Twelve 4-week-old healthy C57BL/6J female mice were randomly divided into high fat diet group and control group with 6 mice in each group. They were fed with high fat diet (22 kJ/g) or normal diet (16 kJ/g) for 12 weeks, respectively. The body weight of mice was measured every week. After feeding for 12 weeks, the body length and width of mice were measured, and the levels of fasting serum triglyceride and total cholesterol were determined. Then the mice were mated with healthy C57BL/6J male mice, and the uterine tissues were collected on the seventh day of pregnancy. The decidual cells and collagen fibers in mouse endometrium was observed by HE staining and Masson staining respectively. The expression of decidual reaction related proteins in mouse endometrium were detected by immunohistochemistry and Western blotting. Mouse endometrial stromal cells (mESCs) were isolated and treated with the oleic acid and palmitic acid in vitro, and the decidual reaction was induced with estradiol and progesterone. The accumulation of lipid droplets in mESCs was observed by oil red O and Bodipy staining. The cytoskeleton of mESCs was observed by phalloidin staining. The levels of decidual reaction related genes and proteins were detected by real-time fluorescence quantitative PCR and Western blotting. RESULTS: After feeding for 12 weeks, the body weight of mice in the high fat group was significantly higher than that in the control group ( P<0.01), and there was no significant difference in body length between two groups ( P>0.05), but the body width of mice in the high fat group was significantly larger than that in the control group ( P<0.01), and the levels of serum triglyceride and total cholesterol were significantly higher than those in the control group (Both P<0.05). The number of embryo implantation in the high fat group was significantly less than that in the control group ( P<0.01). The differentiation of mESCs to decidual cells in high fat group was slow and abnormal. The expression levels of decidual reaction markers bone morphogenetic protein (BMP)2 and homeobox A10 (HOXA10) were lower than those in the control group, and there was significant difference in the expression level of HOXA10 ( P<0.01). The results of oil red O and Bodipy staining in mESCs showed that after high fat treatment, the accumulation of lipid droplets increased significantly, phalloidin staining showed abnormal cytoskeleton morphology. The expression levels of decidual reaction related genes dtprp, HOXA10 and proteins BMP2, HOXA10 and cyclooxygenase (COX)2 were significantly lower than those in the control group ( P<0.05). CONCLUSION: Obesity induced by high fat diet and high fat treatment can impair the decidual reaction of endometrium and endometrial stromal cells in mice.

AMPK/mTOR downregulated autophagy enhances aberrant endometrial decidualization in folate-deficient pregnant mice.

Existing evidence suggests that adverse pregnancy outcomes are closely related to dietary factors. Folate plays an important role in neural tube formation and fetal growth, folate deficiency is a major risk factor of birth defects. Our early studies showed that folate deficiency could impair enddecidualization, however, the mechanism is still unclear. Dysfunctional autophagy is associated with many diseases. Here, we aimed to evaluate the adverse effect of folate deficiency on endometrial decidualization, with a particular focus on endometrial cell autophagy. Mice were fed with no folate diet in vivo and the mouse endometrial stromal cell was cultured in a folate-free medium in vitro. The decrease of the number of endometrial autophagosomes and the protein expressions of autophagy in the folate-deficient group indicated that autophagosome formation, autophagosome-lysosome fusion, and lysosomal degradation were inhibited. Autophagic flux examination using mCherry-GFP-LC3 transfection showed that the fusion of autophagosomes with lysosomes was inhibited by folate deficiency. Autophagy inducer rapamycin could reverse the impairment of folate deficiency on endometrial decidualization. Moreover, folate deficiency could reduce autophagy by disrupting AMPK/mTOR signaling, resulting in aberrant endometrial decidualization and adverse pregnancy outcomes. Further co-immunoprecipitation examination showed that decidual marker protein Hoxa10 could interact with autophagic marker protein Cathepsin L, and the interaction was notably reduced by folate deficiency. In conclusion, AMPK/mTOR downregulated autophagy was essential for aberrant endometrial decidualization in early pregnant mice, which could result in adverse pregnancy outcomes. This provided some new clues for understanding the causal mechanisms of birth defects induced by folate deficiency.

Exposure to ethylparaben and propylparaben interfere with embryo implantation by compromising endometrial decidualization in early pregnant mice.

Ethylparaben (EtP) and propylparaben (PrP) are common preservatives and well-known endocrine-disrupting chemicals. Studies have demonstrated that they can reduce female fertility, but the underlying mechanism, especially that on embryo implantation, is still poorly understood. Endometrial decidualization is a critical event for embryo implantation. In this study, we aimed to explore the effects of EtP/PrP on endometrial decidualization. Pregnant mice were dosed daily by oral gavage with EtP at 0, 400, 800 and 1600 mg/kg or with PrP at 0, 625, 1250 and 2500 mg/kg from Day 1 of pregnancy until sacrifice. The results showed that the rate of pregnant mice with impaired embryo implantation, whose number of implantation sites was less than 7, was significantly increased after exposure to 1600 mg/kg EtP or 2500 mg/kg PrP. Further study found that the expression of endometrial decidualization markers HOXA10, MMP9 and PR was significantly downregulated in 1600 mg/kg EtP group and 2500 mg/kg PrP group. Notably, serum oestrogen and progesterone levels were significantly increased, whereas the expression of uterine oestrogen receptor and progesterone receptor was decreased following 1600 mg/kg EtP or 2500 mg/kg PrP exposure. In the breeding test, fewer offspring were found after females were exposed to 1600 mg/kg EtP or 2500 mg/kg PrP in early pregnancy. This demonstrated that exposure to EtP/PrP interfered with embryo implantation by compromising endometrial decidualization in early-stage pregnant mice. Disorders of reproductive hormones and hormone receptor signals could be responsible for impaired decidualization. This study broadened the understanding on the biological safety of EtP and PrP.

Melatonin alleviates benzo(a)pyrene-induced ovarian corpus luteum dysfunction by suppressing excessive oxidative stress and apoptosis.

Benzo(a)pyrene (B(a)P) is a widespread persistent organic pollutant (POP) and a well-known endocrine disruptor. Exposure to BaP is known to disrupt the steroid balance and impair embryo implantation, but the mechanism under it remains unclear. The corpus luteum (CL), the primary source of progesterone during early pregnancy, plays a pivotal role in embryo implantation and pregnancy maintenance. The inappropriate luteal function may result in implantation failure and spontaneous abortions. Therefore, this study was conducted to assess the effects and potential mechanisms of B(a)P on the CL function. Our results showed that pregnant mice received B(a)P displayed impaired embryo implantation and dysfunction of ovarian CL. The estrogen and progesterone levels decreased by B(a)P. In vitro, exposure to BPDE, which is the metabolite of B(a)P, affected the luteinization of granular cell KK-1. Additionally, melatonin and its receptors, which are important for ovarian function and anti-oxidative damage, were affected by B(a)P or BPDE. B(a)P or BPDE-treated alone impaired antioxidant capacity of ovarian granulosa cells, caused an increasing of ROS and cell apoptosis, and disrupted the PI3K/AKT/GSK3ß signaling pathway in vivo and in vitro. Co-treatment with melatonin alleviated B(a)P or BPDE-induced CL dysfunction by ameliorating oxidative stress, counteracting phosphorylation of PI3K/AKT/GSK3ß signaling pathway, decreasing the apoptosis of the ovarian cells. Moreover, activation of the melatonin receptor by ramelteon in KK-1 cells exhibits an analogous protective effect as melatonin. In conclusion, our findings not only firstly clarify the potential mechanisms of BaP-induced CL dysfunction, but also extend the understanding about the ovarian protection of melatonin and its receptors against B(a)P exposure.

Exposure to ethephon compromises endometrial decidualization in mice during early pregnancy via GPR120.

Exposure to ethephon (ETH), a plant growth regulator commonly used for several purposes, can potentially decrease sperm numbers and viability. Occasional findings regarding ETH effects on female reproduction during early pregnancy have also been reported. During early pregnancy, endometrial decidualization is a critical event for embryo implantation and pregnancy maintenance. Thus, we aimed to explore the effect and mechanism of ETH on endometrial decidualization both in vivo and in vitro. Mice were gavaged with 0 and 285 mg/kg b.w. ETH from gestational days (GD)1 until sacrifice, whereas pseudopregnant mice from pseudopregnant day 1 (PPD-1) until PPD-8. Primary mouse endometrial stromal cells (mESCs) received 640 ug/ml ETH and added E2 and P4 to induce decidualization. Results indicated female albino CD1 mice exposed to high dose of ETH (285 mg/kg b.w.) by oral gavage, the number of embryo implantation sites on GD6 and GD8 were significantly decreased, the levels of serum E2 and P4 on GD8 were significantly decreased. Compared with the control group, the decidualization response artificially induced by corn oil in pseudopregnant mice and by E2 and P4 in primary mouse endometrial stromal cells (mESCs) was weakened in the high dose of ETH treated group. The high dose, 285 mg/kg b.w ETH treated group altered the expression of endometrial decidual markers on GD6 and GD8. The triglyceride and fatty acid metabolism-related genes were significantly increased after female albino CD1 mice exposed to high does, 285 mg/kg b.w ETH on GD6 and GD8. GPR120 was substantially reduced after ETH treatment. When overexpression of GPR120, the compromised decidualization induced by ETH treatment was rescued. Furthermore, molecular docking presented Thr234 and His251 of GPR120 as preferred binding sites for ETH. Mutation of these two sites rescued the compromised decidualization induced by ETH. In conclusion, we demonstrated that ETH exposure could impair decidualization during early pregnancy. GPR120 expression and binding between GPR120 and ETH are crucial for impaired decidualization mediated via ETH.

Phosphorylation of Yes-associated protein impairs trophoblast invasion and migration: implications for the pathogenesis of fetal growth restriction†.

Fetal growth restriction (FGR) is a condition in which a newborn fails to achieve his or her prospective hereditary growth potential. This condition is associated with high newborn mortality, second only to that associated with premature birth. FGR is associated with maternal, fetal, and placental abnormalities. Although the placenta is considered to be an important organ for supplying nutrition for fetal growth, research on FGR is limited, and treatment through the placenta remains challenging, as neither proper uterine intervention nor its pathogenesis have been fully elucidated. Yes-associated protein (YAP), as the effector of the Hippo pathway, is widely known to regulate organ growth and cancer development. Therefore, the correlation of the placenta and YAP was investigated to elucidate the pathogenic mechanism of FGR. Placental samples from humans and mice were collected for histological and biomechanical analysis. After investigating the location and role of YAP in the placenta by immunohistochemistry, we observed that YAP and cytokeratin 7 have corresponding locations in human and mouse placentas. Moreover, phosphorylated YAP (p-YAP) was upregulated in FGR and gradually increased as gestational age increased during pregnancy. Cell function experiments and mRNA-Seq demonstrated impaired YAP activity mediated by extracellular signal-regulated kinase inhibition. Established FGR-like mice also recapitulated a number of the features of human FGR. The results of this study may help to elucidate the association of FGR development with YAP and provide an intrauterine target that may be helpful in alleviating placental dysfunction.

RELATIONSHIP BETWEEN THE ENVIRONMENTAL ENDOCRINE DISRUPTOR BISPHENOL A AND DYSLIPIDEMIA: A FIVE-YEAR PROSPECTIVE STUDY.

Objective: To investigate whether serum bisphenol A (BPA) concentration is related to the occurrence of dyslipidemia. Methods: A total of 574 adults were enrolled at baseline and followed up for 5 years. Concentrations of serum BPA, triglycerides (TGs), low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein (HDL) cholesterol were measured. Dyslipidemia was defined as the existence of one or more of the following conditions: high-LDL-cholesterolemia (LDL ≥140 mg/dL), hypertriglyceridemia (TGs ≥150 mg/dL), or low-HDL-cholesterolemia (HDL <40 mg/dL). Participants were stratified into tertiles according to low, median, and high baseline serum BPA levels. Multivariable linear and logistic regression models were used. Data from baseline and follow-up were used for cross-sectional and longitudinal analyses, respectively. Results: In the cross-sectional analysis, compared to subjects in the low BPA tertile, those in the high BPA tertile showed a higher level of LDL cholesterol (108.1 ± 24.4 mg/dL versus 119.5 ± 26.9 mg/dL; P<.05) and a lower level of HDL cholesterol (46.2 ± 11.7 mg/dL versus 39.5 ± 7.5 mg/dL; P<.05). In multivariable linear regression models, Z-transformed BPA was positively associated with LDL cholesterol (ß= 0.13, P = .002) and negatively associated with HDL cholesterol (ß= -0.28; P<.001). After cross-sectionally adjusting for confounders, subjects in higher BPA exposure was associated with a higher prevalence of low-HDL-cholesterolemia. Longitudinally, in subjects without low-HDL-cholesterolemia at baseline, each SD increment in baseline BPA was associated with a higher incidence of low-HDL-cholesterolemia after adjustment for confounders (odds ratio [95% confidence interval; CI] 2.76, 95% CI 1.21, 6.29). Conclusion: Cross-sectionally, higher BPA exposure is associated with a higher prevalence of low-HDL-cholesterolemia. Longitudinally, baseline BPA is an independent predictor of the 5-year incidence of low-HDL-cholesterolemia. Abbreviations: BMI = body mass index; BPA = bisphenol A; CI = confidence interval; CVD = cardiovascular disease; EIMDS = environment, inflammation and metabolic diseases study; HDL = high density lipoprotein; LDL = low density lipoprotein; OR = odds ratio; PPAR = peroxisome proliferator-activated receptor; SBP = systolic blood pressure; TG = triglyceride; Z-BPA = Z-transformed bisphenol A.

Altered expression patterns of circular RNAs between implantation sites and interimplantation sites in early pregnant mice.

Circular RNAs (circRNAs), a class of newly discovered endogenous noncoding RNAs, have been found to play important roles in regulating gene expression and participate in several biological processes. However, their specific roles in embryo implantation remain unclear. This study aims to investigate the roles of circRNAs in embryo implantation. In the current study, we screened the expression profiles of circRNAs between implantation sites and interimplantation sites in the endometrial tissue of early pregnant mice on Day 5 using microarray assay. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) of four dysregulated circRNAs was performed to validate the microarray results. Bioinformatics analyses, including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and circRNA-microRNA (miRNA)-messenger RNA (mRNA) negative correlation network analyses were performed. The microarray results showed 101 upregulated and 75 downregulated circRNAs (fold change [FC] ≥ 1.5 and p value < 0.05) at implantation sites compared with interimplantation sites. Four randomly selected circRNAs were successfully verified by qRT-PCR. The GO and KEGG analyses revealed some meaningful terms. Moreover, based on circRNAs microarray data and the miRNA and mRNA high-throughput data previously published by our groups, differently expressed circRNAs, miRNAs, and mRNAs were performed to conjoint analysis. Then circRNA-miRNA-mRNA negative correlation networks were constructed and 21 downregulated circRNAs, 14 upregulated miRNAs, and 79 downregulated mRNAs were involved in the networks. The findings of this study may provide a novel perspective on circRNAs and lay a foundation for future research into the potential roles of circRNAs in embryo implantation.

FOXO3a is essential for murine endometrial decidualization through cell apoptosis during early pregnancy.

Embryo implantation is essential for normal pregnancy, and the process of decidualization is critical for embryo implantation. However, the mechanism of decidualization during early pregnancy is still unknown. Forkhead box O3a (FOXO3a) is the most important functional transcription factor of the forkhead box family and is a highly conserved transcription factor of apoptosis-related genes. In the mouse uterus, FOXO3a was found to be expressed regularly from Days 1-7 of early pregnancy. Upon further exploration, it was found that FOXO3a was expressed at significantly higher levels at the implantation site than at the interimplantation site on Days 5-7 of pregnancy. Under artificial decidualization, FOXO3a was highly expressed in the first and second decidual zones. After decidualization, the expression of FOXO3a was significantly increased both in vivo and vitro. In primary stromal cells, apoptosis was reduced by decreased expression of FOXO3a after inducing decidualization. Moreover, when FOXO3a-small interfering RNA was transfected into the uteri of mice, the expression of decidualization- and apoptosis-related factors was impaired. Thus, FOXO3a might play an important role in decidualization during early pregnancy, and cell apoptosis might be one of pathways for FOXO3a-regulated decidualization.

Benzo(a)pyrene inhibits endometrial cell apoptosis in early pregnant mice via the WNT5A pathway.

Benzo(a)pyrene (BaP) is an endocrine-disrupting pollutant present in various aspects of daily life, and studies have demonstrated that BaP exerts reproductive toxicity. We previously showed that BaP damages endometrial morphology and decreases the number of implantation sites in early pregnant mice, but the mechanisms underlying these effects remain unclear. The endometrial function is crucial for implantation, which is associated with endometrial cell apoptosis. In this study, we focused on the effect of BaP on endometrial cell apoptosis and the role of WNT signaling during this process. Pregnant mice were gavaged with corn oil (control group) or 0.2 mg·kg-1 ·day -1 BaP (treatment group) from Days 1 to 6 of pregnancy. BaP impaired endometrial function by decreasing the expression of HOXA10 and BMP2, two markers of receptivity and decidualization. WNT5A and ß-catenin were activated in the BaP group. BaP affected the expression of apoptosis-related proteins and inhibited the apoptosis of endometrial stromal cells. In vitro, human endometrial stromal cells (HESCs) were treated with different concentrations of BaP (dimethyl sulfoxide (DMSO); 5, 10 µM). WNT5A and ß-catenin were also upregulated in the BaP treatment group. HESC apoptosis was restrained by BaP. Inhibiting WNT5A by SFRP5 partially restored the effect of BaP on apoptosis. In summary, these results suggested that BaP exposure during early pregnancy activates WNT5A/ß-catenin signaling pathway, which inhibits the endometrial cell apoptosis and potentially destroys endometrial function.

The Regulation of Trophoblastic p53 Homeostasis by the p38-Wip1 Feedback Loop is Disturbed in Placentas from Pregnancies Complicated by Preeclampsia.

BACKGROUND/AIMS: Excessive apoptosis of trophoblasts, induced by sustained hypoxia, leads to abnormal placentation and is strongly linked to pregnancy complications such as preeclampsia (PE). Wild-type p53-induced phosphatase (Wip1) positively regulates cellular survival in tumor cells through the p38 and p53 pathways, but its expression pattern and effects in trophoblasts have yet to be reported. This study clarified the effect of Wip1 on the regulatory mechanism of p53-dependent apoptosis in trophoblasts, and thus increases understanding of the etiology of PE. METHODS: In normal and PE placentas, Wip1 mRNA and protein levels were determined by RT-qPCR and Western blotting respectively, while localization of Wip1 in placental tissues and in HTR8/SVneo cells was determined by immunohistochemistry and immunofluorescence. Two in vitro trophoblastic PE models were established by subjecting HTR8/SVneo cells to either hypoxia intervention in incubator (HII) or simulated ischemic buffer (SIB). Wip1 was suppressed in the aforementioned PE models by specific inhibitor or shRNA, and apoptosis was then assessed by flow cytometry, while further validation was done by measurement of cleaved-caspase 9 expression by Western blotting. The p38 inhibitor SB202190, Mdm2 inhibitor NVP-CGM097, and proteasome inhibitor MG-132 were administered in PE models, either in combination or alone, to determine the regulatory order of the component signal molecules of the feedback loop. The impact of Wip1 on p53-Mdm2 interaction was examined by coimmunoprecipitation. Lastly, the upregulation of the p38-Wip1 loop was confirmed in human placentas from pregnancies complicated by PE, using Western blotting. RESULTS: Wip1 expression was significantly elevated in human PE placentas and in vitro trophoblastic PE models; this is opposite to the pattern observed in tumor cells. Inhibition of Wip1 rescued hypoxia-induced p38 activation, cleavage of caspase 9 and apoptosis but significantly compromised p53-Mdm2 binding, while p-p53Ser15 was increased. Inhibition of Mdm2 degradation resulted in p53 destabilization and p38-Wip1 loop down-regulation, while degradation of the p53-Mdm2 complex resulted in p53 accumulation and p38-Wip1 loop hyperactivation. However, the p53-Mdm2 interaction was found to be more important in the regulation of the p38-Wip1 loop than Mdm2 stability. CONCLUSION: Trophoblastic p53 homeostasis is maintained by the p38-Wip1 feedback regulatory loop in response to hypoxic stress, which is dysregulated in the placentas of pregnancies complicated by PE, and thereby leads to excessive apoptosis.