Polychlorinated biphenyls impair endometrial receptivity in vitro via regulating mir-30d expression and epithelial mesenchymal transition

Advances in polychlorinated biphenyls-induced female reproductive toxicity

Polychlorinated biphenyls (PCBs) are a class of endocrine-disrupting chemicals (EDCs) widely present in the environment. PCBs have been of concern due to their anti/estrogen-like effects, which make them more toxic to the female reproductive system. However, there is still a lack of systematic reviews on the reproductive toxicity of PCBs in females, so the adverse effects and mechanisms of PCBs on the female reproductive system were summarized in this paper. Our findings showed that PCBs are positively associated with lower pregnancy rate, hormone disruption, miscarriage and various reproductive diseases in women. In animal experiments, PCBs can damage the structure and function of the ovaries, uterus and oviducts. Also, PCBs could produce epigenetic effects and be transferred to the offspring through the maternal placenta, causing development retardation, malformation and death of embryos, and damage to organs of multiple generations. Furthermore, the mechanisms of PCBs-induced female reproductive toxicity mainly include receptor-mediated hormone disorders, oxidative stress, apoptosis, autophagy, and epigenetic modifications. Finally, we also present some directions for future research on the reproductive toxicity of PCBs. This detailed information provided a valuable reference for fully understanding the reproductive toxicity of PCBs.

Mechanisms of LPS-induced epithelial mesenchymal transition in bEECs

High-concentrate diets cause subacute ruminal acidosis, resulting in increased blood lipopolysaccharide (LPS) levels in cows. We found that the peak LPS in cows fed with high-concentrate diets coincides the period of embryo implantation in a large-scale dairy farm. As epithelial-mesenchymal transition (EMT) should be tightly regulated during normal embryo implantation in cows, we speculated that increased LPS may cause abnormal EMT, thereby inhibiting embryo implantation in cows. To confirm that elevated LPS levels induce abnormal EMT in cows, we treated bovine endometrial epithelial cells (bEECs) with LPS for 48 h and analyzed the protein levels of ZEB1, a major EMT-related transcription factor, which is positively regulated by the TGFβ/SMAD3 pathway. In addition, we analyzed the changes in expression of three EMT-related genes (E-cadherin, N-cadherin, and Vimentin), and examined the morphology and migratory ability of the cells. The results showed that elevated LPS levels increased protein expression of ZEB1, vimentin, and N-cadherin, and reduced that of E-cadherin. Elevated LPS also increased bEECs migration rate, and induced the cells to acquire a mesenchymal phenotype. Furthermore, benzyl butyl phthalate (BBP)-induced ZEB1 overexpression significantly decreased E-cadherin levels and increased N-cadherin levels. As LPS treatment also decreased the expression of Bta-miR-200b, we further found that Bta-miR-200b targets to the 3'UTR of ZEB1 through the confirmation of dual-luciferase reporter system. And the increased level of Bta-miR-200b by mimic enhanced the expression of E-cadherin and yet inhibited the expression of N-cadherin in protein, which exactly opposite to the results induced by LPS. In conclusion, LPS induced EMT in bEECs by upregulating ZEB1, while Bta-miR-200b could inhibit the occurrence of EMT by binding ZEB1 3'UTR. These results provide a new insight for low reproductive rate of dairy cows under the background of high-concentrate diets.

MicroRNAs, small regulatory elements with significant effects on human implantation: a review

Embryo implantation is a critical process for achieving a successful pregnancy and live birth. The proper implantation must have a synchronized interaction between blastocyst and a receptive endometrium. Many genes are involved in the modulation of precise molecular events during implantation. MicroRNAs (miRNAs) have been extensively reported as gene regulatory molecules on post-transcriptional levels involved in various biological processes such as gametogenesis, embryogenesis, and the quality of sperm, oocyte, and embryos. A plethora of evidence has demonstrated critical roles for miRNAs in regulating genes involved in the implantation process; hence, dysregulation of miRNAs could be associated with significant impairments in implantation, such as recurrent implantation failure. In addition to the indispensable role of miRNAs in the intracellular control of gene expression, they can also be secreted into extracellular fluid and circulation. Therefore, miRNAs in body fluids and blood may be exploited as non-invasive diagnostic biomarkers for different pathological and physiological conditions. Recently, several studies have focused on the discovery of miRNAs function in the implantation process by appraising miRNAs and their target genes in human embryos, endometrial tissue, and cell culture models. Moreover, it was revealed that there could be a significant association between endometrial receptivity or implantation status and the expression of miRNAs in human body fluids, reinforcing their role as non-invasive biomarkers. In the current work, we reviewed the studies concerning the role of intracellular and extracellular miRNAs in human implantation and the influence of their dysregulation on implantation disorders.

Effect of Zhujingqiaoyun Receptivity of Infertility with Kidney Deficiency Based on Ultrasonic Evaluation

Objective

This study aims to explore the effect of the prescription for Zhujingqiaoyun receptivity in patients with infertility.

Methods

This project is a prospective randomized controlled clinical study, including infertility diagnostic criteria and dialectical kidney deficiency patients. 60 cases were randomly divided into 2 groups: the control group, where medication complex packing estradiol tablets were given, and the treatment group, on the basis of the control group, which was given Zhujingqiaoyun receptivity plus or minus. Transvaginal ultrasound was used to observe the endometrial thickness, endometrial volume, endometrial blood supply, and other aspects of patients in the two groups to evaluate the endometrial receptivity before and after treatment, and to record the pregnancy rate and safety of patients in the two groups after three menstrual cycles.

Results

There was no significant difference in age, course of disease, and endometrial thickness between the two groups (P > 0.05). Before and after treatment, the endometrial thickness of the two groups increased significantly, and the uterine artery blood flow pulsatility index (PI) and resistance index (RI) decreased significantly (P < 0.05). The endometrial volume in the control group was significantly lower than that in the treatment group, and the difference was statistically significant (P < 0.05). The endometrial FI and VFI in the control group were significantly lower than those in the treatment group, and the difference was statistically significant (P < 0.05). In the treatment group, 30 cases were treated for 3 months, and 11 of those were pregnant (36.7%). There were 30 cases in the control group, and 5 cases were pregnant (16.67%). Both groups had good safety. SPSS 22.0 statistical software was used for the chi-square test.

Conclusion

Zhujingqiaoyun receptivity on endometrial receptivity can treat infertility patients with good efficacy, increasing endometrial thickness and reducing uterine artery blood flow index. It is worthy of clinical promotion to improve pregnancy rates.

Single Cell Proteomics Profiling Reveals That Embryo-Secreted TNF-α Plays a Critical Role During Embryo Implantation to the Endometrium

It has been long-known that endometrium-secreted cytokines play a critical role during embryo implantation. However, whether cytokines secreted from the embryo are relevant to the process of embryo implantation remains unclear. The concentration of cytokines in embryo culture medium was tested using a newly developed, high-sensitivity single-cell proteomic platform and evaluated in comparison to embryo quality and clinical outcome. The effect of TNF-α on embryo and endometrium Ishikawa cells was investigated using immunofluorescence staining, CCK-8 assay, TUNEL staining, and RT-qPCR. Of the 10 cytokines measured, only TNF-α concentration was significantly higher in the group with embryo implantation failure. Immunofluorescence staining showed that the expression of TNF-α was unevenly distributed in blastocysts, and the expression level was significantly correlated with the blastocyst inner cell mass (ICM) quality score. Gene profiling showed that addition of TNF-α led to increased expression of tumor necrosis factor receptor 1 (TNFR1) and apoptosis-related genes and that this could be inhibited by the TNF-α receptor inhibitor etanercept (ETA). In addition, an increased expression of water and ion channels, including AQP3, CFTR, ENaCA, and CRISP2 was also observed which could also be inhibited by ETA. Our results show that higher embryo-secreted TNF-α levels are associated with implantation failure through activation of TNF-α receptor, and TNF-α may be an independent predictor for pre-transfer assessment of the embryo development potential in IVF patients.

Epigenetic alterations induced by genotoxic occupational and environmental human chemical carcinogens: An update of a systematic literature review

Epigenetic alterations, such as changes in DNA methylation, histones/chromatin structure, nucleosome positioning, and expression of non-coding RNAs, are recognized among key characteristics of carcinogens; they may occur independently or concomitantly with genotoxic effects. While data on genotoxicity are collected through standardized guideline tests, data collected on epigenetic effects is far less uniform. In 2016, we conducted a systematic review of published studies of genotoxic carcinogens that reported epigenetic endpoints to better understand the evidence for epigenetic alterations of human carcinogens, and the potential association with genotoxic endpoints. Since then, the number of studies of epigenetic effects of chemicals has nearly doubled. This review stands as an update on epigenetic alterations induced by occupational and environmental human carcinogens that were previously and recently classified as Group 1 by the International Agency for Research on Cancer. We found that the evidence of epigenetic effects remains uneven across agents. Studies of DNA methylation are most abundant, while reports concerning effects on non-coding RNA have increased over the past 5 years. By contrast, mechanistic toxicology studies of histone modifications and chromatin state alterations remain few. We found that most publications of epigenetic effects of carcinogens were studies in exposed humans or human cells. Studies in rodents represent the second most common species used for epigenetic studies in toxicology, in vivo exposures being the most predominant. Future studies should incorporate dose- and time-dependent study designs and also investigate the persistence of effects following cessation of exposure, considering the dynamic nature of most epigenetic alterations.

Expression and significance of miR-30d-5p and SOCS1 in patients with recurrent implantation failure during implantation window

BACKGROUND

Poor endometrial receptivity is a major factor that leads to recurrent implantation failure. However, the traditional method cannot accurately evaluate endometrial receptivity. Various studies have indicated that microRNAs (miRNAs) are involved in multiple processes of embryo implantation, but the role of miRNAs in endometrial receptivity in patients with recurrent implantation failure (RIF) remains elusive. In the present study, we investigated the presence of pinopodes and the roles of miR-30d-5p, suppressor of cytokine signalling 1 (SOCS1) and the leukaemia inhibitory factor (LIF) pathway in women with a history of RIF during the implantation window.

METHODS

Endometrial tissue samples were collected between January 2018 to June 2019 from two groups of women who underwent in vitro fertilisation and embryo transfer (IVF-ET) or frozen ET. The RIF group included 20 women who underwent ≥ 3 ETs, including a total of ≥ 4 good-quality embryos, without pregnancy, whereas the control group included 10 women who had given birth at least once in the past year. An endometrial biopsy was performed during the implantation window (LH + 7). The development of pinopodes in the endometrial biopsy samples from all groups was evaluated using scanning electron microscopy (SEM). Quantitative reverse transcription-polymerase chain reaction and western blotting were used to investigate the expression levels of miR-30d-5p, SOCS1, and the LIF pathway.

RESULTS

The presence of developed pinopodes decreased in patients with RIF on LH + 7. The expression level of miR-30d-5p decreased in the endometria during the implantation window of patients with RIF, whereas the mRNA and protein levels of SOCS1 were significantly higher in the RIF group than in the control group. Furthermore, a negative correlation was observed between the expression of miR-30d-5p and SOCS1 (r² = 0.8362). In addition, a significant decrease in LIF and p-STAT3 expression was observed during the implantation window in patients with RIF.

CONCLUSIONS

MiR-30d-5p and SOCS1 may be potential biomarkers for endometrial receptivity. Changes in pinopode development and abnormal expression of miR-30d-5p, SOCS1 and LIF pathway in the endometrium could be the reasons for implantation failure.

Secreted MicroRNA to Predict Embryo Implantation Outcome: From Research to Clinical Diagnostic Application

Embryo implantation failure is considered a leading cause of infertility and a significant bottleneck for in vitro fertilization (IVF) treatment. Confirmed factors that lead to implantation failure involve unhealthy embryos, unreceptive endometrium, and asynchronous development and communication between the two. The quality of embryos is further dependent on sperm parameters, oocyte quality, and early embryo development after fertilization. The extensive involvement of such different factors contributes to the variability of implantation potential across different menstrual cycles. An ideal approach to predict the implantation outcome should not compromise embryo implantation. The use of clinical material, including follicular fluid, cumulus cells, sperm, seminal exosomes, spent blastocyst culture medium, blood, and uterine fluid, that can be collected relatively non-invasively without compromising embryo implantation in a transfer cycle opens new perspectives for the diagnosis of embryo implantation potential. Compositional comparison of these samples between fertile women and women or couples with implantation failure has identified both quantitative and qualitative differences in the expression of microRNAs (miRs) that hold diagnostic potential for implantation failure. Here, we review current findings of secreted miRs that have been identified to potentially be useful in predicting implantation outcome using material that can be collected relatively non-invasively. Developing non-invasive biomarkers of implantation potential would have a major impact on implantation failure and infertility.

The role of mesenchymal-epithelial transition in endometrial function

BACKGROUND

The human uterine endometrium undergoes significant remodeling and regeneration on a rapid and repeated basis, after parturition, menstruation, and in some cases, injury. The ability of the adult endometrium to undergo cyclic regeneration and differentiation/decidualization is essential for successful human reproduction. Multiple key physiologic functions of the endometrium require the cells of this tissue to transition between mesenchymal and epithelial phenotypes, processes known as mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT). Although MET/EMT processes have been widely characterized in embryonic development and in the context of malignancy, mounting evidence demonstrates the importance of MET/EMT in allowing the endometrium the phenotypic and functional flexibility necessary for successful decidualization, regeneration/re-epithelialization and embryo implantation.

OBJECTIVE AND RATIONALE

The objective of this review is to provide a comprehensive summary of the observations concerning MET and EMT and their regulation in physiologic uterine functions, specifically in the context of endometrial regeneration, decidualization and embryo implantation.

SEARCH METHODS

Using variations of the search terms 'mesenchymal-epithelial transition', 'mesenchymal-epithelial transformation', 'epithelial-mesenchymal transition', 'epithelial-mesenchymal transformation', 'uterus', 'endometrial regeneration', 'endometrial decidualization', 'embryo implantation', a search of the published literature between 1970 and 2018 was conducted using the PubMed database. In addition, we searched the reference lists of all publications included in this review for additional relevant original studies.

OUTCOMES

Multiple studies demonstrate that endometrial stromal cells contribute to the regeneration of both the stromal and epithelial cell compartments of the uterus, implicating a role for MET in mechanisms responsible for endometrial regeneration and re-epithelialization. During decidualization, endometrial stromal cells undergo morphologic and functional changes consistent with MET in order to accommodate embryo implantation. Under the influence of estradiol, progesterone and multiple other factors, endometrial stromal fibroblasts acquire epithelioid characteristics, such as expanded cytoplasm and rough endoplasmic reticulum required for greater secretory capacity, rounded nuclei, increased expression of junctional proteins which allow for increased cell-cell communication, and a reorganized actin cytoskeleton. During embryo implantation, in response to both maternal and embryonic-derived signals, the maternal luminal epithelium as well as the decidualized stromal cells acquire the mesenchymal characteristics of increased migration/motility, thus undergoing EMT in order to accommodate the invading trophoblast.

WIDER IMPLICATIONS

Overall, the findings support important roles for MET/EMT in multiple endometrial functions required for successful reproduction. The endometrium may be considered a unique wound healing model, given its ability to repeatedly undergo repair without scarring or loss of function. Future studies to elucidate how MET/EMT mechanisms may contribute to scar-free endometrial repair will have considerable potential to advance studies of wound healing mechanisms in other tissues.

MicroRNA-30d deficiency during preconception affects endometrial receptivity by decreasing implantation rates and impairing fetal growth

BACKGROUND

Maternal-embryonic crosstalk between the endometrium and the preimplantation embryo is required for normal pregnancy. Our previous results demonstrated that maternal microRNAs secreted into the endometrial fluid, specifically miR-30d, act as a transcriptomic regulator of the preimplantation embryo by the maternal intrauterine environment.

OBJECTIVE

To investigate the reproductive and fetal effects of murine miR-30d deficiency at the maternal-embryonic interface according to the origin of its maternal or embryonic default.

STUDY DESIGN

A miR-30d knockout murine model was used as the animal model to investigate the impact of maternal and/or embryonic origin of miR-30d deficiency on embryonic implantation and fetal development. Wild-type and miR-30d knockout pseudopregnant mice were used to study the effect of miR-30d deficiency on the receptivity markers by means of real-time quantitative polymerase chain reaction, immunofluorescence, and western blotting. We assessed receptivity markers and implantation rates in 6 different transfer conditions in which embryos obtained from wild-type, knockout, and knockout embryos pretreated with a miR-30d analog were transferred into either wild-type or knockout pseudopregnant females. The impact of miR-30d deficiency on fetal development was evaluated by analyzing the implantation sites and resorbing sites under physiological conditions at days 5, 6, 8, and 12 of pregnancy. Fetal growth was evaluated by analyzing fetuses and placentas at days 12 and 16 of pregnancy.

RESULTS

Maternal miR-30d deficiency induced a significant downregulation of endometrial receptivity markers. In wild-type recipients, miR-30d knockout embryos had poorer implantation rates than wild-type embryos (48.86 ± 14.33% vs 75.00 ± 10.47%, respectively, P = .0061). In miR-30d knockout recipients, the lowest implantation rate was observed when knockout embryos were transferred compared to wild-type embryos (26.04 ± 7.15% and 49.71 ± 8.59%, respectively, P = .0059). A positive correlation (r = 0.9978) was observed for maternal leukemia inhibitor factor expression with implantation rates. Further, the course of gestation was compromised in miR-30d knockout mothers, which had smaller implantation sites, greater rates of resorption, and fetuses with smaller crown-rump length and fetal/placental weight ratio.

CONCLUSION

Our results demonstrate that maternal and/or embryonic miR-30d deficiency impairs embryonic implantation and fetal development in the animal model. This finding adds a novel miRNA dimension to the understanding of pregnancy and fetal growth restriction in humans.

Protective effect of ginger (Zingiber officinale) against PCB-induced acute hepatotoxicity in male rats

After absorption by the organism, polychlorinated biphenyls (PCBs) cross cellular membranes and pass into blood vessels and the lymphatic system. It is generally in the liver, adipose tissues, brain and skin that we find the strongest concentrations of PCBs. Herbal medicine remains as a discipline intended to treat and to prevent certain functional disorders and/or pathologies caused by oxidative stress, which can be induced by pesticides, medicines or pollutants. The objective of this study is to verify the toxic and oxidative effects of PCBs and to investigate the protective effect of ginger (Zingiber officinale) in the liver of male rats of the “Wistar” strain. These rats are divided into 6 groups: a control group (T), two groups treated with PCB at two different concentrations (P₁ and P₂), a group treated with ginger extract (G), a group pretreated with ginger extract and then injected with the first concentration of PCBs (P₁G), and a group pretreated with ginger and then injected with the second concentration of PCBs (P₂G). The results showed that the administration of PCBs led to an increase in the relative weight of the liver, and a significant increase in all of the hepatic biomarker levels (glucose, cholesterol, triglycerides, AST, ALT, and LDH) in the serum. Furthermore, an increase in the rate of lipid peroxidation and a decrease in the antioxidant enzyme activities (catalase, superoxide dismutase and glutathione peroxidase) were observed under the influence of PCBs in the liver. The histological test showed that the PCBs induced hepatocyte vacuolization, prominent and peripheralized nuclei, hepatocellular hypertrophy and turgor of the vein in the centriacinar regions. Pretreatment with ginger extract restored all of the biochemical and oxidative parameters to the normal values and reduced the injuries caused by the PCBs. In conclusion, in our experimental conditions, ginger effectively protects the liver against the hepatotoxic effects induced by PCBs.

After absorption by the organism, polychlorinated biphenyls (PCBs) cross cellular membranes and pass into blood vessels and the lymphatic system.

Selective estrogen receptor modulator ormeloxifene suppresses embryo implantation via inducing miR-140 and targeting insulin-like growth factor 1 receptor in rat uterus

Ormeloxifene, the non-steroidal SERM contraceptive, inhibits endometrial receptivity and embryo implantation via countering nidatory estrogen. However, the molecular mechanism of ormeloxifene action responsible for its contraceptive efficacy still remains unclear. Herein, we aimed to identify the miRNAs modulated under the influence of ormeloxifene and to explore their role in endometrial receptivity and embryo implantation. By doing microRNA sequencing analysis, a total of 168 miRNAs were found to be differentially expressed in uterine tissue of ormeloxifene-treated rats, on day 5 (10:00 h) of pregnancy i.e. peri-implantation period. Out of differentially expressed miRNAs, miR-140 expression was found to be elevated in ormeloxifene administered groups and was selected for detailed investigation. In-vivo gain-of-function of miR-140 resulted in a significant reduction of implantation sites indicating its role in embryo implantation. The experiment on delayed implantation showed that estradiol caused down-regulation of miR-140. It also suppressed the attachment and outgrowth of BeWo spheroids to RL95-2 endometrial cells. In transwell migration assay, miR-140 was found to be involved in suppression of migration and invasion of endometrial epithelial cells. The ormeloxifene treatment caused up-regulation of miR-140 along with down-regulated expression of its target IGF1R in endometrial epithelial and stromal cells which also led to the suppression of downstream effectors integrin β3 and FAK. In mimic miR-140 receiving horn, the reduced expression of IGF1R was observed along with suppressed downstream integrin β3 and FAK similar to that observed in uteri of ormeloxifene- treated rats. Taken together, these findings suggest that ormeloxifene-induced inhibition of embryo implantation occurs via inducing miR-140 and altering its target IGF1R in rat uterus.

miR-26a promoted endometrial epithelium cells (EECs) proliferation and induced stromal cells (ESCs) apoptosis via the PTEN-PI3K/AKT pathway in dairy goats

Changes in endometrial cell morphology and function are absolutely necessary for successful embryo implantation. In this study, miR-26a was widely expressed in dairy goats, and was found to be regulated by β-estradiol (E2) and progesterone (P4) in endometrial epithelium cells (EECs) as well as stromal cells (ESCs). Furthermore, miR-26a played a role in the regulation of cells proliferation and apoptosis by directly regulating PTEN and indirectly regulating the PI3K/AKT pathway in EECs but not in ESCs of dairy goats in vitro. In addition, miR-26a regulated the expression of osteopontin (OPN), vascular endothelial growth factor (VEGF), Cyclooxygenase-2 (COX-2), and prolactin (PRL) in endometrial cells. Therefore, we could get a conclusion that miR-26a had very complex and diverse functions in the endometrial cells during the development of endometrial receptivity in dairy goats. This study provided an efficient platform for studying the regulatory effect of miR-26a on endometrial cells during the development of endometrial receptivity in dairy goats.

miR-182 aids in receptive endometrium development in dairy goats by down-regulating PTN expression

Increasing evidence has shown that miRNAs play important roles in endometrium development during the menstrual cycle in humans and many other animals. Our previous data indicated that miR-182 levels increase 15.55-fold and pleiotrophin (PTN) levels decrease 20.97-fold in the receptive endometrium (RE, D15) compared with the pre-receptive endometrium (PE, D5) in dairy goats. The present study shows that miR-182 is widely expressed in different tissues of dairy goats and that its expression levels are regulated by E2 and P4 in endometrial epithelium cells (EECs). We confirmed that PTN is a target of miR-182 and that miR-182 regulates the protein levels of AKT, Bcl-2, FAS, MAPK, Caspase-3 and SP1 in EECs. Furthermore, miR-182 up-regulates or maintains the expression levels of osteopontin (OPN), cyclooxygenase-2 (COX-2) and prolactin receptor (PRLR) in EECs, suggesting that miR-182 is an important regulatory factor in the construction of endometrial receptivity in dairy goats. In conclusion, miR-182 participates in the development of endometrial receptivity by down-regulating PTN and affecting the expression of select apoptosis-related genes and increasing or maintaining the expression levels of OPN, COX-2 and PRLR in the EECs of dairy goats.