Role of STAT signaling and autocrine action of chemokines during H2 O 2 induced HTR-8/SVneo trophoblastic cells invasion

Her2 amplification, Rel-A, and Bach1 can influence APOBEC3A expression in breast cancer cells

APOBEC-induced mutations occur in 50% of sequenced human tumors, with APOBEC3A (A3A) being a major contributor to mutagenesis in breast cancer cells. The mechanisms that cause A3A activation and mutagenesis in breast cancers are still unknown. Here, we describe factors that influence basal A3A mRNA transcript levels in breast cancer cells. We found that basal A3A mRNA correlates with A3A protein levels and predicts the amount of APOBEC signature mutations in a panel of breast cancer cell lines, indicating that increased basal transcription may be one mechanism leading to breast cancer mutagenesis. We also show that alteration of ERBB2 expression can drive A3A mRNA levels, suggesting the enrichment of the APOBEC mutation signature in Her2-enriched breast cancer could in part result from elevated A3A transcription. Hierarchical clustering of transcripts in primary breast cancers determined that A3A mRNA was co-expressed with other genes functioning in viral restriction and interferon responses. However, reduction of STAT signaling via inhibitors or shRNA in breast cancer cell lines had only minor impact on A3A abundance. Analysis of single cell RNA-seq from primary tumors indicated that A3A mRNA was highest in infiltrating immune cells within the tumor, indicating that correlations of A3A with STAT signaling in primary tumors may be result from higher immune infiltrates and are not reflective of STAT signaling controlling A3A expression in breast cancer cells. Analysis of ATAC-seq data in multiple breast cancer cell lines identified two transcription factor sites in the APOBEC3A promoter region that could promote A3A transcription. We determined that Rel-A, and Bach1, which have binding sites in these peaks, elevated basal A3A expression. Our findings highlight a complex and variable set of transcriptional activators for A3A in breast cancer cells.

Unraveling the molecular mechanisms driving enhanced invasion capability of extravillous trophoblast cells: a comprehensive review

Precise extravillous trophoblast (EVT) invasion is crucial for successful placentation and pregnancy. This review focuses on elucidating the mechanisms that promote heightened EVT invasion. We comprehensively summarize the pivotal roles of hormones, angiogenesis, hypoxia, stress, the extracellular matrix microenvironment, epithelial-to-mesenchymal transition (EMT), immunity, inflammation, programmed cell death, epigenetic modifications, and microbiota in facilitating EVT invasion. The molecular mechanisms underlying enhanced EVT invasion may provide valuable insights into potential pathogenic mechanisms associated with diseases characterized by excessive invasion, such as the placenta accreta spectrum (PAS), thereby offering novel perspectives for managing pregnancy complications related to deficient EVT invasion.

Biomarkers of oxidative stress and reproductive complications

Oxidative stress is the result of an imbalance between the formation of reactive oxygen species (ROS) and the levels of enzymatic and non-enzymatic antioxidants. The assessment of biological redox status is performed by the use of oxidative stress biomarkers. An oxidative stress biomarker is defined as any physical structure or process or chemical compound that can be assessed in a living being (in vivo) or in solid or fluid parts thereof (in vitro), the determination of which is a reproducible and reliable indicator of oxidative stress. The use of oxidative stress biomarkers allows early identification of the risk of developing diseases associated with this process and also opens up possibilities for new treatments. At the end of the last century, interest in oxidative stress biomarkers began to grow, due to evidence of the association between the generation of free radicals and various pathologies. Up to now, a significant number of studies have been carried out to identify and apply different oxidative stress biomarkers in clinical practice. Among the most important oxidative stress biomarkers, it can be mentioned the products of oxidative modifications of lipids, proteins, nucleic acids, and uric acid as well as the measurement of the total antioxidant capacity of fluids in the human body. In this review, we aim to present recent advances and current knowledge on the main biomarkers of oxidative stress, including the discovery of new biomarkers, with emphasis on the various reproductive complications associated with variations in oxidative stress levels.

IL-6 and IL-8: An Overview of Their Roles in Healthy and Pathological Pregnancies

Interleukin-6 (IL-6) is an acknowledged inflammatory cytokine with a pleiotropic action, mediating innate and adaptive immunity and multiple physiological processes, including protective and regenerative ones. IL-8 is a pro-inflammatory CXC chemokine with a primary function in attracting and activating neutrophils, but also implicated in a variety of other cellular processes. These two ILs are abundantly expressed at the feto-maternal interface over the course of a pregnancy and have been shown to participate in numerous pregnancy-related events. In this review, we summarize the literature data regarding their role in healthy and pathological pregnancies. The general information related to IL-6 and IL-8 functions is followed by an overview of their overall expression in cycling endometrium and at the feto-maternal interface. Further, we provide an overview of their involvement in pregnancy establishment and parturition. Finally, the implication of IL-6 and IL-8 in pregnancy-associated pathological conditions, such as pregnancy loss, preeclampsia, gestational diabetes mellitus and infection/inflammation is discussed.

Inflammation-Related Molecules at the Maternal-Fetal Interface during Pregnancy and in Pathologically Altered Endometrium

The blastocyst expresses paternally derived alloantigens and induces inflammation during implantation. However, it is necessary for the onset of pregnancy. An abnormal response might result in a pathological course of pregnancy or pregnancy failure. On the other hand, a state of maternal immune tolerance is necessary to ensure the normal development of pregnancy by suppressing inflammatory processes. This article discusses recognized mechanisms and the significance of inflammatory processes for embryo implantation and pregnancy establishment. We would also like to present disorders involving excessive inflammatory response and their influence on events occurring during embryo implantation. The chain of correlation between the processes responsible for embryo implantation and the subsequent physiological course of pregnancy is complicated. Many of those interrelationships are still yet to be discovered. Undoubtedly, their recognition will give hope to infertile couples for the emergence of new treatments that will increase the chance of giving birth to a healthy child.

Maternal Exercise-Induced SOD3 Reverses the Deleterious Effects of Maternal High-Fat Diet on Offspring Metabolism Through Stabilization of H3K4me3 and Protection Against WDR82 Carbonylation

Preclinical studies reveal maternal exercise as a promising intervention to reduce the transmission of multigenerational metabolic dysfunction caused by maternal obesity. The benefits of maternal exercise on offspring health may arise from multiple factors and have recently been shown to involve DNA demethylation of critical hepatic genes leading to enhanced glucose metabolism in offspring. Histone modification is another epigenetic regulator, yet the effects of maternal obesity and exercise on histone methylation in offspring are not known. Here, we find that maternal high-fat diet (HFD; 60% kcal from fat) induced dysregulation of offspring liver glucose metabolism in C57BL/6 mice through a mechanism involving increased reactive oxygen species, WD repeat-containing 82 (WDR82) carbonylation, and inactivation of histone H3 lysine 4 (H3K4) methyltransferase leading to decreased H3K4me3 at the promoters of glucose metabolic genes. Remarkably, the entire signal was restored if the HFD-fed dams had exercised during pregnancy. WDR82 overexpression in hepatoblasts mimicked the effects of maternal exercise on H3K4me3 levels. Placental superoxide dismutase 3 (SOD3), but not antioxidant treatment with N-acetylcysteine was necessary for the regulation of H3K4me3, gene expression, and glucose metabolism. Maternal exercise regulates a multicomponent epigenetic system in the fetal liver resulting in the transmission of the benefits of exercise to offspring.

miR-219a suppresses human trophoblast cell invasion and proliferation by targeting vascular endothelial growth factor receptor 2 (VEGFR2)

OBJECTIVE

Vascular endothelial growth factor (VEGF) plays a critical role in regulating trophoblast cell invasion and proliferation, involved in a variety of pregnancy complications, such as spontaneous abortion and pre-eclampsia. Numerous studies have revealed that microRNAs (miRNAs) are participated in a series of molecular processes that regulate cell function, such as cell invasion, proliferation, and apoptosis. Vascular endothelial growth factor receptor 2 (VEGFR2), a receptor of VEGF, has been shown to be involved in trophoblast function. However, the relation between miRNA and VEGFR2 and their role in trophoblast function remain to be elucidated.

METHODS

The effect of miR-219a on the trophoblast function has been explored using luciferase reporter, transwell, qRT-PCR, western blot, bromodeoxyuridine (BrdU), ELISA, immunofluorescent staining, and tube formation assays.

RESULTS

In the current study, we observed that through targeted inhibition of VEGFR2 expression by miR-219a, the function of VEGFR2 as well as the downstream PI3K/AKT/NF-κB signaling pathway were suppressed, leading to suppression of trophoblastic proliferation and invasion. Moreover, upregulation of VEGFR2 restored the miR-219a-inhibited cell proliferation, invasion, and tube formation.

CONCLUSIONS

These results revealed that miR-219a played crucial roles in negatively regulating trophoblastic proliferation and invasion by suppression of the PI3K/AKT/NF-κB signaling pathway by targeting VEGFR2, therefore serving as a potential treatment method for the complications of pregnancy caused by trophoblastic dysregulation.

Involvement of signal transducers and activators of transcription in trophoblast differentiation

INTRODUCTION

To explore the involvement of signal transducers and activators of transcription (STATs) in trophoblast differentiation.

METHODS AND RESULTS

First, the localization of STATs in human placentas was detected via immunohistochemistry (IHC) and immunofluorescence (IF). Cytotrophoblasts (CTBs) expressed both STAT1 and 3, but syncytiotrophoblasts (STBs) did not. Staining for these two proteins showed a distinct upregulation from the proximal part to the distal end of cell columns. STAT5B was mainly expressed in the STBs, low in the CTBs, and absent in the extravillous trophoblasts (EVTs). Next, the 44 placenta samples were tested via western blot (WB) and quantitative real time polymerase chain reaction (qRT-PCR). We found a decrease in STAT1 and 3 and an increase in STAT5B as gestation increased from five to 10 weeks. Then, an in vitro co-culture model of placenta with or without decidua stromal cells (DSCs), as detected via flow cytometry, revealed an increase in the human leukocyte antigen (HLA)-G positive rate in trophoblasts from placentas co-cultured with DSCs, accompanied by an increase in p-STAT1 and 3 and a decrease in p-STAT5 and STAT5B. Finally, mRNA of matrix metalloproteinases (MMPs) and integrins after STAT silencing in HTR-8/SVneo was detected via qRT-PCR. STAT1 silencing decreased MMP9 expression, STAT3 silencing decreased MMP9, integrin α6, and β4 expression, and STAT5B silencing increased MMP2 and integrin β1 expression.

DISCUSSION

Different trophoblasts showed distinct STAT expression profiles which were related to their MMP and integrin expression. DSCs promoted trophoblast differentiation into EVTs, possibly by regulating the STAT expression of the trophoblasts.

GPx8 Expression in Rat Oocytes, Embryos, and Female Genital Organs During Preimplantation Period of Pregnancy

This study aimed to detect the presence of glutathione peroxidase 8 (GPx8) in rat during preimplantation period of pregnancy. Females were killed on first (D1), third (D3), and fifth (D5) day of pregnancy. The presence of GPx8 in embryos was detected under the confocal microscope, the presence of GPx8 in genital organs was confirmed immunohistochemically, and the amount of GPx8 was determined using densitometry. We found that GPx8 is dispersed in the cytoplasm of oocytes, while after fertilization, it is concentrated in granules. From 4-cell stage till blastocyst, GPx8 reaction was found in the perinuclear region. In the ovary, GPx8 was seen in granulosa-lutein cells, in plasma of blood vessels, and inside Graafian follicles. In oviduct, GPx8 was detected in the plasma and in the extracellular matrix (ECM). Moreover, epithelial cells of isthmus were positive. In uterus, GPx8 was observed in the uterine glands, in the plasma, and in ECM. On D5, the enzyme disappeared from the uterine glands and appeared in fibroblasts. Densitometry revealed that the highest amount of GPx8 was on D1 and subsequently declined. To our knowledge, this is the first paper describing GPx8 presence in the oocytes, preimplantation embryos, and female genital organs in mammals. Our results improve the understanding of antioxidant enzymes presence during pregnancy in defense against oxidative stress, which is considered to be one of the main causes of infertility.

EGF-mediated reduced miR-92a-1-5p controls HTR-8/SVneo cell invasion through activation of MAPK8 and FAS which in turn increase MMP-2/-9 expression

The members of human miR-17-92 cluster are implicated in several cancers and are known to increase cancer cells invasiveness. The present study reports reduced expression of miR-92a-1-5p in EGF treated HTR-8/SVneo trophoblastic cells by NGS and qRT-PCR. Overexpression of miR-92a-1-5p led to significantly reduced EGF-mediated HTR-8/SVneo cells invasion. MAPK8 and FAS were predicted to be miR-92a-1-5p targets, and confirmed to be reduced by qRT-PCR and Western blotting in trophoblast cells overexpressing miR-92a-1-5p. The binding of miR-92a-1-5p to MAPK8 and FAS 3'-UTR was confirmed by Luciferase reporter assay and Rescue assay. EGF increases MMP-2 & MMP-9 expression and reduces TIMP1 expression in HTR-8/SVneo cells. Inhibition of MAPK8 (by SP600125) reduced EGF-mediated MMP-9/TIMP1 ratio and invasion. Similarly, silencing of FAS by siRNA reduced EGF-mediated MMP-2/TIMP1 ratio and invasion. Treatment of HTR-8/SVneo cells with STAT1/3 inhibitors or siRNAs led to loss of EGF-mediated reduction in miR-92a-1-5p levels. Inserting the predicted binding sites of STAT3 present in promoter region of miR-92a-1-5p upstream of Luciferase promoter reduced its expression in presence of STAT3 expression vector. Thus, EGF leads to reduced miR-92a-1-5p expression which may be regulated by STAT1/STAT3 and controls HTR-8/SVneo cells invasion by targeting MAPK8 and FAS, which in turn increases MMP-2/MMP-9 expression.

BCL2L15 Depletion Inhibits Endometrial Receptivity via the STAT1 Signaling Pathway

In domestic ruminants, endometrial receptivity is critical for a successful pregnancy and economic efficiency. Although the endometrium undergoes major cellular changes during peri-implantation, the precise mechanisms regulating goat endometrial receptivity remain unknown. In this study, we investigated the functional roles and signal transduction of the B-cell lymphoma 2 (Bcl-2)-like protein 15 (BCL2L15) in the regulation of endometrial receptivity in vitro. Our results showed that BCL2L15 was up-regulated in goat endometrial epithelial cells (EECs) under progesterone (P₄), estradiol (E₂), and interferon-tau (IFN-τ) treatments. Our knockdown of BCL2L15 by specific shRNA that significantly hampered endometrial receptivity. In the absence of BCL2L15, the signal transducer and activator of transcription (STAT)1 and STAT3 pathway were activated. Additionally, pretreatment with the STAT1 inhibitor, fludarabine, restored the effect of silencing BCL2L15 on the endometrial receptivity, but not the STAT3 inhibitor Stattic. Overall, these results suggested that BCL2L15 is the key regulator of endometrial receptivity in goats, regulating the endometrial receptivity through the STAT1 pathway. Understanding the function of BCL2L15-STAT1 in endometrial receptivity is important to the exploration of new targets for the diagnosis and treatment of early pregnancy failure, and improving the success rates for artificial reproduction.

New Insights into the Process of Placentation and the Role of Oxidative Uterine Microenvironment

For a successful pregnancy to occur, a predecidualized receptive endometrium must be invaded by placental differentiated cells (extravillous trophoblast cells (EVTs)) and, at the same time, continue decidualization. EVT invasion is aimed at anchoring the placenta to the maternal uterus and ensuring local blood supply increase necessary to provide normal placental and foetal development. The first is achieved by migrating through the maternal endometrium and deeper into the myometrium, while the second by transforming uterine spiral arteries into large vessels. This process is a tightly regulated battle comprising interests of both the mother and the foetus. Invading EVTs are required to perform a scope of functions: move, adhere, proliferate, differentiate, interact, and digest the extracellular matrix (ECM); tolerate hypoxia; transform the maternal spiral arteries; and die by apoptosis. All these functions are modulated by their surrounding microenvironment: oxygen, soluble factors (e.g., cytokines, growth factors, and hormones), ECM proteins, and reactive oxygen species. A deeper comprehension of oxidative uterine microenvironment contribution to trophoblast function will be addressed in this review.

The enhancer RNA lnc-SLC4A1-1 epigenetically regulates unexplained recurrent pregnancy loss (URPL) by activating CXCL8 and NF-kB pathway

Background

Enhancer RNAs (eRNAs) are a group of lncRNAs transcribed from enhancers, whose regulatory effects on gene expression are an emerging area of interest. However, the role of eRNAs in regulating trophoblast cells and unexplained recurrent pregnancy loss (URPL) remains elusive.

Methods

We profiled eRNAs in villi from URPL patients and matched controls by RNA-seq. Functions of URPL-related eRNAs were further investigated in vitro.

Results

We identified lnc-SLC4A1-1, which was transcribed from an active enhancer marked with H3K27ac and H3K4me1 and so-called eRNA, highly expressed in URPL patients. Gain-of-function experiments indicated that lnc-SLC4A1-1 facilitated trophoblast cell migration and apoptosis. Mechanistically, as an eRNA, lnc-SLC4A1-1 was retained in the nuclei and recruited transcription factor NF-κB to bind to CXCL8, resulting in increased H3K27ac in the CXCL8 promoter and subsequent elevation of CXCL8 expression. Activation of CXCL8 exacerbated inflammatory reactions in trophoblast cells by inducing TNF-α and IL-1β, which could be blocked by an antagonist of lnc-SLC4A1-1.

Interpretation

These findings indicate that an eRNA, lnc-SLC4A1-1, alters trophoblast function via activation of immune responses and by regulating the NF-κB/CXCL8 axis. Our study provides new insights in understanding lncRNA/eRNA function in pathological pregnancy, potentially informing on therapeutic strategies for URPL.

Fund

National Natural Science Foundation of China, Natural Science Foundation of Jiangsu Province, National Key Research and Development Program, the Priority Academic Program for the Development of Jiangsu Higher Education Institutions.