Estradiol promotes trophoblast viability and invasion by activating SGK1

Uteroplacental microvascular remodeling in health and disease

The microvascular system is essential for delivering oxygen and nutrients to tissues while removing metabolic waste. During pregnancy, the uteroplacental microvascular system undergoes extensive remodeling to meet the increased demands of the fetus. Key adaptations include vessel dilation and increases in vascular volume, density, and permeability, all of which ensure adequate placental perfusion while maintaining stable maternal blood pressure. Structural and functional abnormalities in the uteroplacental microvasculature are associated with various gestational complications, posing both immediate and long-term risks to the health of both mother and infant. In this review, we describe the changes in uteroplacental microvessels during pregnancy, discuss the pathogenic mechanisms underlying diseases such as preeclampsia, fetal growth restriction, and gestational diabetes, and summarize current clinical and research approaches for monitoring microvascular health. We also provide an update on research models for gestational microvascular complications and explore solutions to several unresolved challenges. With advancements in research techniques, we anticipate significant progress in understanding and managing these diseases, ultimately leading to new therapeutic strategies to improve maternal and fetal health.

Upregulated YTHDC1 mediates trophoblastic dysfunction inducing preterm birth in ART conceptions through enhanced RPL37 translation

Assisted reproductive technology (ART) pregnancies present a higher risk of singleton preterm birth than natural pregnancies, but the underlying molecular mechanism remains largely unknown. RNA m6A modification is a key epigenetic mechanism regulating cellular function, but the role of m6A modification, especially its "reader" YTHDC1, in preterm delivery remains undefined. To delineate the role and epigenetic mechanism of m6A modification in ART preterm delivery, the effects of YTHDC1 on trophoblastic function were evaluated by CCK-8, EdU, Transwell, and flow cytometry analyses post its overexpression or knockdown. Downstream signaling pathways of YTHDC1 were investigated by RNA-seq, and targeted mRNAs were explored by RIP-seq and MeRIP-seq. Upstream transcriptional factors of YTHDC1 were determined by ChIP-seq and luciferase reporter assays. Elevated YTHDC1 was detected in human ART-conceived preterm placentas and in murine preterm placentas post estradiol (E2) exposure. In vitro experiments showed that YTHDC1 promoted trophoblastic cell proliferation and migration, but inhibited cell apoptosis. Mechanistically, E2 was proven to upregulate YTHDC1 expression via retinoid X receptor alpha (RXRA) in trophoblastic cells. Enhanced YTHDC1 expression augmented the translation of RPL37 in an m6A-dependent manner by binding to m6A-modified RPL37 mRNA and concomitantly promoted the overall translational output. Importantly, administration of siRNA targeting YTHDC1 effectively delayed the progression of preterm delivery. In conclusion, the identified E2/RXRA/YTHDC1/RPL37 axis provides new insights into the epigenetic mechanism underlying ART-associated preterm delivery. The findings offer a potential prognostic biomarker and therapeutic target for preterm delivery.

Unlocking trophectoderm mysteries: In vivo and in vitro perspectives on human and mouse trophoblast fate induction

In recent years, the pursuit of inducing the trophoblast stem cell (TSC) state has gained prominence as a compelling research objective, illuminating the establishment of the trophoblast lineage and unlocking insights into early embryogenesis. In this review, we examine how advancements in diverse technologies, including in vivo time course transcriptomics, cellular reprogramming to TSC state, chemical induction of totipotent stem-cell-like state, and stem-cell-based embryo-like structures, have enriched our insights into the intricate molecular mechanisms and signaling pathways that define the mouse and human trophectoderm/TSC states. We delve into disparities between mouse and human trophectoderm/TSC fate establishment, with a special emphasis on the intriguing role of pluripotency in this context. Additionally, we re-evaluate recent findings concerning the potential of totipotent-stem-like cells and embryo-like structures to fully manifest the trophectoderm/trophoblast lineage's capabilities. Lastly, we briefly discuss the potential applications of induced TSCs in pregnancy-related disease modeling.

The role of serum-glucocorticoid regulated kinase 1 in reproductive viability: implications from prenatal programming and senescence

OBJECTIVE

Organisms and cellular viability are of paramount importance to living creatures. Disruption of the balance between cell survival and apoptosis results in compromised viability and even carcinogenesis. One molecule involved in keeping this homeostasis is serum-glucocorticoid regulated kinase (SGK) 1. Emerging evidence points to a significant role of SGK1 in cell growth and survival, cell metabolism, reproduction, and life span, particularly in prenatal programming and reproductive senescence by the same token. Whether the hormone inducible SGK1 kinase is a major driver in the pathophysiological processes of prenatal programming and reproductive senescence?

METHOD

The PubMed/Medline, Web of Science, Embase/Ovid, and Elsevier Science Direct literature databases were searched for articles in English focusing on SGK1 published up to July 2023 RESULT: Emerging evidence is accumulating pointing to a pathophysiological role of the ubiquitously expressed SGK1 in the cellular and organismal viability. Under the regulation of specific hormones, extracellular stimuli, and various signals, SGK1 is involved in several biological processes relevant to viability, including cell proliferation and survival, cell migration and differentiation. In line, SGK1 contributes to the development of germ cells, embryos, and fetuses, whereas SGK1 inhibition leads to abnormal gametogenesis, embryo loss, and truncated reproductive lifespan.

CONCLUTION

SGK1 integrates a broad spectrum of effects to maintain the homeostasis of cell survival and apoptosis, conferring viability to multiple cell types as well as both simple and complex organisms, and thus ensuring appropriate prenatal development and reproductive lifespan.

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.

Combined Effects of Polystyrene Nanosphere and Homosolate Exposures on Estrogenic End Points in MCF-7 Cells and Zebrafish

BACKGROUND

Micro- and nanoplastics (MNPs) and homosalate (HMS) are ubiquitous emerging environmental contaminants detected in human samples. Despite the well-established endocrine-disrupting effects (EDEs) of HMS, the interaction between MNPs and HMS and its impact on HMS-induced EDEs remain unclear.

OBJECTIVES

This study aimed to investigate the influence of MNPs on HMS-induced estrogenic effects and elucidate the underlying mechanisms in vitro and in vivo.

METHODS

We assessed the impact of polystyrene nanospheres (PNSs; 50  nm , 1.0 mg / L ) on HMS-induced MCF-7 cell proliferation (HMS: 0.01 - 1 μ M , equivalent to 2.62 - 262 μ g / L ) using the E-SCREEN assay and explored potential mechanisms through transcriptomics. Adult zebrafish were exposed to HMS (0.0262 - 262 μ g / L ) with or without PNSs (50  nm , 1.0 mg / L ) for 21 d. EDEs were evaluated through gonadal histopathology, fertility tests, steroid hormone synthesis, and gene expression changes in the hypothalamus-pituitary-gonad-liver (HPGL) axis.

RESULTS

Coexposure of HMS and PNSs resulted in higher expression of estrogen receptor α (ESR1) and the mRNAs of target genes (pS2, AREG, and PGR), a greater estrogen-responsive element transactivation activity, and synergistic stimulation on MCF-7 cell proliferation. Knockdown of serum and glucocorticoid-regulated kinase 1 (SGK1) rescued the MCF-7 cell proliferation induced by PNSs alone or in combination with HMS. In zebrafish, coexposure showed higher expression of SGK1 and promoted ovary development but inhibited spermatogenesis. In addition, coexposure led to lower egg hatchability, higher embryonic mortality, and greater larval malformation. Coexposure also modulated steroid hormone synthesis genes (cyp17a2, hsd17[Formula: see text]1, esr2b, vtg1, and vtg2), and resulted in higher 17 β -estradiol (E 2 ) release in females. Conversely, males showed lower testosterone, E 2 , and gene expressions of cyp11a1, cyp11a2, cyp17a1, cyp17a2, and hsd17[Formula: see text]1.

DISCUSSION

PNS exposure exacerbated HMS-induced estrogenic effects via SGK1 up-regulation in MCF-7 cells and disrupting the HPGL axis in zebrafish, with gender-specific patterns. This offers new mechanistic insights and health implications of MNP and contaminant coexposure. https://doi.org/10.1289/EHP13696.

Jiawei Shoutai Pill promotes decidualization by regulating the SGK1/ENaC pathway in recurrent spontaneous abortion

ETHNOPHARMACOLOGICAL RELEVANCE

Jiawei Shoutai Pill (JWSTW) is a traditional herbal formula for recurrent spontaneous abortion (RSA). Although JWSTW significantly improves the clinical symptoms of RSA patients, its molecular mechanism remains unclear.

AIM OF STUDY

This study evaluated the expression and function of the serum/glucocorticoid regulated kinase 1/epithelial sodium channel (SGK1/ENaC) pathway and decidualization level in RSA patients and mice. It also investigated the therapeutic effects and potential mechanisms of JWSTW.

MATERIALS AND METHODS

30 early RSA patients and 30 normal pregnant women undergoing induced abortion during the same period were included in the study. Decidual tissues were collected, and HE staining, immunohistochemistry, Western blot, and RT-PCR were used to detect protein and mRNA expression levels of SGK1, ENaC-a, estrogen Rreceptor β (ERβ), and progesterone receptor (PR) in patients' decidual tissues. Protein expression levels of prolactin receptor (PRLR) and insulin-like growth factor binding protein 1 (IGFBP-1) were also detected. A classical RSA mouse model was constructed, and the mice were randomly divided into four groups: normal, model, dydrogesterone (DQYT) (0.33 g/kg/d), and JWSTW (1.66 g/kg/d). The normal and model groups received the same volume of distilled water by gavage for 8 and 14 days after pregnancy. On the 14th day of pregnancy, the embryonic loss rate of each group, the number of offspring born to naturally delivered mice, and the protein or mRNA expression levels of key factors of the SGK1/ENaC pathway (SGK1, ENaC-a, ERβ, and PR), decidual proliferation marker (Ki67), mesenchymal-epithelial transition (E-cadherin and Vimentin), and decidualization markers (PRLR and IGFBP-1) in mouse decidual tissue on the eighth day of pregnancy were observed.

RESULTS

The decidual tissue structure of RSA patients was abnormal. Immunohistochemical analysis revealed significantly reduced positive expression of SGK1, ENaC-a, ERβ, and PR proteins in the decidual tissue of RSA patients (P < 0.001). Western blot and RT-PCR analyses demonstrated significantly decreased protein and mRNA expression of SGK1, ENaC-a, ERβ, and PR in the decidual tissue of RSA patients (all P < 0.05). Additionally, protein expression of PRLR and IGFBP-1 was significantly reduced (both P < 0.001). The RSA mouse model exhibited a significant increase in embryo loss rate and decreased litter size (both P < 0.001). Treatment with DQYT and JWSTW rescued the embryo loss rate and litter size to varying extents (all P < 0.05). The protein or mRNA expression levels of SGK1, ENaC-a, ERβ, PR, Ki67, E-cadherin, vimentin, PRLR, and IGFBP-1 in RSA mice were improved to different degrees after treatment with DQYT and JWSTW (all P < 0.05).

CONCLUSIONS

Abnormal SGK1/ENaC signaling pathway regulation is closely associated with early endometrial damage in RSA patients. JWSTW promotes endometrial proliferation and mesenchymal-epithelial transition through the SGK1/ENaC signaling pathway, improving endometrial shedding. Consequently, JWSTW is a potential treatment for RSA.

Isolation of Human Villous Cytotrophoblastic Cells from Term Placenta for Transfection

Isolation of villous cytotrophoblastic cells (vCTBs) from placental tissue provides the possibility of studying differentiation of these cells as well as their function. We describe herein a protocol, in which term placentas are used to isolate a population of vCTB in high quantities. These cells are subsequently used to transfect siRNA through microporation and thereby to achieve efficient silencing of targeted genes.

Activation of SGK1/ENaC Signaling Pathway Improves the Level of Decidualization in Unexplained Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) is one of the most common complications during pregnancy and seriously affects women's physical and mental health. About 50% of RSA cases are of unknown etiology. Our previous study found that the decidual tissue of patients with unexplained recurrent spontaneous abortion (URSA) had low expression levels of serum and glucocorticoid-induced protein kinase (SGK) 1. Endometrial decidualization is a key link in the early stage of pregnancy and is crucial to the development and maintenance of pregnancy. Decidualization is the proliferation and differentiation of endometrial stromal cells into deciduals, which involves a complex physiological process such as ovarian steroid hormones (estrogen, progesterone, prolactin, etc.), growth factors, and intercellular signaling. The binding of estrogen and its receptor stimulates the synthesis of endometrial deciduating markers prolactin (PRL) and insulin-like growth factor binding protein 1 (IGFBP-1), which mediates the occurrence of decidualization. Among them, SGK1/ENaC is a signaling pathway closely related to decidualization. The purpose of this study was to further investigate the expression of SGK1 and decidualization-related molecules in the decidual tissue of URSA patients and to explore the potential mechanism of SGK1's protective effect in URSA patients and in mouse models. Decidual tissue samples from 30 URSA patients and 30 women who actively terminated pregnancy were collected, and a URSA mouse model was established and treated with dydrogesterone. Expression levels of SGK1 and its signaling pathway-related proteins (p-Nedd4-2, 14-3-3 protein and ENaC-a), estrogen and progesterone receptors (ERβ, PR), and decidualization markers (PRLR, IGFBP-1) were assessed. Our study found that SGK1, p-Nedd4-2, 14-3-3 proteins, and ENaC-a expression levels were reduced in the decidual tissue, the SGK1/ENaC signaling pathway was inhibited, and the expression levels of the decidualization markers PRLR and IGFBP-1 were downregulated in the URSA group compared with the controls. Additionally, the concentrations of E2, P, and PRL in the serum of mice were decreased in the URSA group compared with the controls. However, SGK1/ENaC pathway-related proteins, estrogen and progesterone and their receptors, and decidualization-related molecules were upregulated by dydrogesterone. These data suggest that estrogen and progesterone can induce decidualization by activating the SGK1/ENaC signaling pathway; disruption of this pathway can lead to the development of URSA. Dydrogesterone can increase the expression level of SGK1 protein in decidual tissue.

Spatial and temporal expression profile of sex steroid receptors and antioxidant enzymes in the maternal-fetal interface of domestic cats

Sex steroids and antioxidant enzymes modulate uterine and placental physiology. Failures in the expression, signaling, and/or secretion of these mediators are associated with female infertility and gestational problems. However, there is no data on the expression profile of receptors for sex steroids and antioxidant enzymes in the maternal-fetal interface of domestic cats. Uterus and placenta samples from non-pregnant diestrus cats and cats in mid- and late pregnancy were used to analyze the protein and gene expression of the receptors for estrogen alpha (ERα), progesterone (PR), and androgen (AR) and the antioxidant enzymes superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 1 (GPX1) by immunohistochemistry and qPCR. Higher uterine expression of ERα, Pr, and Sod1 was observed in the pregnant cats, especially in mid-pregnancy, compared to non-pregnant diestrus cats, as well as reduced endometrial catalase immunostaining. In the placenta, the mRNA expression of Erα, Pr, Ar, and Gpx1 was higher in late pregnancy in relation to mid-pregnancy. Moreover, weak or no placental expression was observed for catalase in mid- and late pregnancy, while strong immunostaining was observed for AR in trophoblasts and decidual cells in mid-pregnancy. The findings of this study demonstrated that pregnancy in female cats increases the uterine expression of sex steroid receptors and antioxidant enzymes, and that the placental expression of these mediators varies according to gestational age.

The EstroGene Database Reveals Diverse Temporal, Context-Dependent, and Bidirectional Estrogen Receptor Regulomes in Breast Cancer

As one of the most successful cancer therapeutic targets, estrogen receptor-α (ER/ESR1) has been extensively studied over the past few decades. Sequencing technological advances have enabled genome-wide analysis of ER action. However, comparison of individual studies is limited by different experimental designs, and few meta-analyses are available. Here, we established the EstroGene database through unified processing of data from 246 experiments including 136 transcriptomic, cistromic, and epigenetic datasets focusing on estradiol (E2)-triggered ER activation across 19 breast cancer cell lines. A user-friendly browser (https://estrogene.org/) was generated for multiomic data visualization involving gene inquiry under user-defined experimental conditions and statistical thresholds. Notably, annotation of metadata associated with public datasets revealed a considerable lack of experimental details. Comparison of independent RNA-seq or ER ChIP-seq data with the same design showed large variability and only strong effects could be consistently detected. Temporal estrogen response metasignatures were defined, and the association of E2 response rate with temporal transcriptional factors, chromatin accessibility, and heterogeneity of ER expression was evaluated. Unexpectedly, harmonizing 146 E2-induced transcriptomic datasets uncovered a subset of genes harboring bidirectional E2 regulation, which was linked to unique transcriptional factors and highly associated with immune surveillance in the clinical setting. Furthermore, the context dependent E2 response programs were characterized in MCF7 and T47D cell lines, the two most frequently used models in the EstroGene database. Collectively, the EstroGene database provides an informative and practical resource to the cancer research community to uniformly evaluate key reproducible features of ER regulomes and unravels modes of ER signaling.

SIGNIFICANCE

A resource database integrating 246 publicly available ER profiling datasets facilitates meta-analyses and identifies estrogen response temporal signatures, a bidirectional program, and model-specific biases.

Estrogen-sensitive activation of SGK1 induces M2 macrophages with anti-inflammatory properties and a Th2 response at the maternal-fetal interface

BACKGROUND

Decidual macrophages participate in immune regulation at the maternal-fetal interface. Abnormal M1/M2 polarization of decidual macrophages might predispose immune maladaptation in recurrent pregnancy loss (RPL). However, the mechanism of decidual macrophage polarization is unclear. We explored the role of Estradiol (E₂)-sensitive serum-glucocorticoid regulated kinase (SGK) 1 in promoting macrophage polarization and suppressing inflammation at the maternal-fetal interface.

METHODS

We assessed serum levels of E₂ and progesterone during first trimester of pregnancy in women with or without threatened miscarriages (ended in live birth, n = 448; or early miscarriages, n = 68). For detection of SGK1 in decidual macrophages, we performed immunofluorescence labeling and western blot analysis applying decidual samples from RPL (n = 93) and early normal pregnancy (n = 66). Human monocytic THP-1 cells were differentiated into macrophages and treated with Toll-like receptor (TLR) 4 ligand lipopolysaccharide (LPS), E₂, inhibitors or siRNA for in vitro analysis. Flow cytometry analysis were conducted to detect macrophages polarization. We also applied ovariectomized (OVX) mice with hormones exploring the mechanisms underlying the regulation of SGK1 activation by E₂ in the decidual macrophages in vivo.

RESULTS

SGK1 expression down regulation in the decidual macrophages of RPL was consistent with the lower concentration and slower increment of serum E₂ from 4 to 12 weeks of gestation seen in these compromised pregnancies. LPS reduced SGK1 activities, but induced the pro-inflammatory M1 phenotype of THP-1 monocyte-derived macrophages and T helper (Th) 1 cytokines that favored pregnancy loss. E₂ pretreatment promoted SGK1 activation in the decidual macrophages of OVX mice in vivo. E₂ pretreatment amplified SGK1 activation in TLR4-stimulated THP-1 macrophages in vitro through the estrogen receptor beta (ERβ) and PI3K pathway. E₂-sensitive activation of SGK1 increased M2 macrophages and Th2 immune responses, which were beneficial to successful pregnancy, by inducing ARG1 and IRF4 transcription, which are implicated in normal pregnancy. The experiments on OVX mice have shown that pharmacological inhibition of E₂ promoted nuclear translocation of NF-κB in the decidual macrophages. Further more, pharmacological inhibition or knockdown of SGK1 in TLR4-stimulated THP-1 macrophages activated NF-κB by promoting its nuclear translocation, leading to increased secretion of pro-inflammatory cytokines involved in pregnancy loss.

CONCLUSION

Our findings highlighted the immunomodulatory roles of E₂-activated SGK1 in Th2 immune responses by priming anti-inflammatory M2 macrophages at the maternal-fetal interface, resulting in a balanced immune microenvironment during pregnancy. Our results suggest new perspectives on future preventative strategies for RPL.

Estrogen Actions in Placental Vascular Morphogenesis and Spiral Artery Remodeling: A Comparative View between Humans and Mice

Estrogens, mainly 17β-estradiol (E2), play a critical role in reproductive organogenesis, ovulation, and fertility via estrogen receptors. E2 is also a well-known regulator of utero-placental vascular development and blood-flow dynamics throughout gestation. Mouse and human placentas possess strikingly different morphological configurations that confer important reproductive advantages. However, the functional interplay between fetal and maternal vasculature remains similar in both species. In this review, we briefly describe the structural and functional characteristics, as well as the development, of mouse and human placentas. In addition, we summarize the current knowledge regarding estrogen actions during utero-placental vascular morphogenesis, which includes uterine angiogenesis, the control of trophoblast behavior, spiral artery remodeling, and hemodynamic adaptation throughout pregnancy, in both mice and humans. Finally, the estrogens that are present in abnormal placentation are also mentioned. Overall, this review highlights the importance of the actions of estrogens in the physiology and pathophysiology of placental vascular development.

EstroGene database reveals diverse temporal, context-dependent and directional estrogen receptor regulomes in breast cancer

As one of the most successful cancer therapeutic targets, estrogen receptor-α (ER/ESR1) has been extensively studied in decade-long. Sequencing technological advances have enabled genome-wide analysis of ER action. However, reproducibility is limited by different experimental design. Here, we established the EstroGene database through centralizing 246 experiments from 136 transcriptomic, cistromic and epigenetic datasets focusing on estradiol-treated ER activation across 19 breast cancer cell lines. We generated a user-friendly browser ( https://estrogene.org/ ) for data visualization and gene inquiry under user-defined experimental conditions and statistical thresholds. Notably, documentation-based meta-analysis revealed a considerable lack of experimental details. Comparison of independent RNA-seq or ER ChIP-seq data with the same design showed large variability and only strong effects could be consistently detected. We defined temporal estrogen response metasignatures and showed the association with specific transcriptional factors, chromatin accessibility and ER heterogeneity. Unexpectedly, harmonizing 146 transcriptomic analyses uncovered a subset of E2-bidirectionally regulated genes, which linked to immune surveillance in the clinical setting. Furthermore, we defined context dependent E2 response programs in MCF7 and T47D cell lines, the two most frequently used models in the field. Collectively, the EstroGene database provides an informative resource to the cancer research community and reveals a diverse mode of ER signaling.

LDHA deficiency inhibits trophoblast proliferation via the PI3K/AKT/FOXO1/CyclinD1 signaling pathway in unexplained recurrent spontaneous abortion

Dysregulated trophoblast proliferation, invasion, and apoptosis may cause several pregnancy-associated complications, such as unexplained recurrent spontaneous abortion (URSA). Recent studies have shown that metabolic abnormalities, including glycolysis inhibition, may dysregulate trophoblast function, leading to URSA. However, the underlying mechanisms remain unclear. Herein, we found that lactate dehydrogenase A (LDHA), a key enzyme in glycolysis, was significantly reduced in the placental villus of URSA patients. The human trophoblast cell line HTR-8/SVneo was used to investigate the possible LDHA-mediated regulation of trophoblast function. LDHA knockdown in HTR-8/SVneo cells induced G0/G1 phase arrest and increased apoptosis, whereas LDHA overexpression reversed these effects. Next, RNA sequencing combined with Kyoto Encyclopedia of Genes and Genomes analysis demonstrated that the PI3K/AKT signaling pathway is potentially affected by downstream genes of LDHA. Especially, we found that LDHA knockdown decreased the phosphorylation levels of PI3K, AKT, and FOXO1, resulting in a significant downregulation of CyclinD1. In addition, treatment with an AKT inhibitor or FOXO1 inhibitor also verified that the PI3K/AKT/FOXO1 signaling pathway influenced the gene expression of CyclinD1 in trophoblast. Moreover, p-AKT expression correlated positively with LDHA expression in syncytiotrophoblasts and extravillous trophoblasts in first-trimester villus. Collectively, this study revealed a new regulatory pathway for LDHA/PI3K/AKT/FOXO1/CyclinD1 in the trophoblast cell cycle and proliferation.

Loss of function of the maternal membrane oestrogen receptor ERα alters expansion of trophoblast cells and impacts mouse fertility

The binding of 17β-oestradiol to oestrogen receptor alpha (ERα) plays a crucial role in the control of reproduction, acting through both nuclear and membrane-initiated signalling. To study the physiological role of membrane ERα in the reproductive system, we used the C451A-ERα mouse model with selective loss of function of membrane ERα. Despite C451A-ERα mice being described as sterile, daily weighing and ultrasound imaging revealed that homozygous females do become pregnant, allowing the investigation of the role of ERα during pregnancy for the first time. All neonatal deaths of the mutant offspring mice resulted from delayed parturition associated with failure in pre-term progesterone withdrawal. Moreover, pregnant C451A-ERα females exhibited partial intrauterine embryo arrest at about E9.5. The observed embryonic lethality resulted from altered expansion of Tpbpa-positive spiral artery-associated trophoblast giant cells into the utero-placental unit, which is associated with an imbalance in expression of angiogenic factors. Together, these processes control the trophoblast-mediated spiral arterial remodelling. Hence, loss of membrane ERα within maternal tissues clearly alters the activity of invasive trophoblast cells during placentogenesis. This previously unreported function of membrane ERα could open new avenues towards a better understanding of human pregnancy-associated pathologies.

Transcriptomic Profile Identifies Hippocampal Sgk1 as the Key Mediator of Ovarian Estrogenic Regulation on Spatial Learning and Memory and Aβ Accumulation

Previous studies have shown that ovarian estrogens are involved in the occurrence and pathology of Alzheimer's disease (AD) through regulation on hippocampal synaptic plasticity and spatial memory; however, the underlying mechanisms have not yet been elucidated at the genomic scale. In this study, we established the postmenopausal estrogen-deficient model by ovariectomy (OVX). Then, we used high-throughput Affymetrix Clariom transcriptomics and found 143 differentially expressed genes in the hippocampus of OVX mice with the absolute fold change ≥ 1.5 and P < 0.05. GO analysis showed that the highest enrichment was seen in long-term memory. Combined with the response to steroid hormone enrichment and GeneMANIA network prediction, the serum and glucocorticoid-regulated kinase 1 gene (Sgk1) was found to be the most potent candidate for ovarian estrogenic regulation. Sgk1 overexpression viral vectors (oSgk1) were then constructed and injected into the hippocampus of OVX mice. Morris water maze test revealed that the impaired spatial learning and memory induced by OVX was rescued by Sgk1 overexpression. Additionally, the altered expression of synaptic proteins and actin remodeling proteins and changes in CA1 spine density and synapse density induced by OVX were also significantly reversed by oSgk1. Moreover, the OVX-induced increase in Aβ-producing BACE1 and Aβ and the decrease in insulin degrading enzyme were significantly reversed by oSgk1. The above results show that multiple pathways and genes are involved in ovarian estrogenic regulation of the function of the hippocampus, among which Sgk1 may be a novel potent target against estrogen-sensitive hippocampal dysfunctions, such as Aβ-initiated AD.

Circ-CCNB1 Modulates Trophoblast Proliferation and Invasion in Spontaneous Abortion by Regulating miR-223/SIAH1 axis

CONTEXT

Spontaneous abortion (SA) is a common disorder in early pregnancy. Circular RNAs (circRNAs) have been reported to exert important regulatory effects on trophoblast function and embryo development.

OBJECTIVE

The aim of this study was to explore whether and how circRNAs regulate trophoblast function in SA during early pregnancy.

METHODS

Cell proliferation, 5-bromo-2-deoxyuridine (BrdU) staining, Transwell, immunofluorescence, Western blot, RNA pull-down, and dual luciferase reporter assays were performed to investigate the effect of circRNA cyclin B1 (circ-CCNB1) on trophoblast function in HTR-8/SVneo and JEG-3 cells.

RESULTS

An in vitro study demonstrated that upregulation of circ-CCNB1 significantly inhibited trophoblast proliferation and invasion compared with the controls using HTR-8/SVneo and JEG-3 cells, respectively. Moreover, miR-223 was downregulated in the villous tissues of patients with SA and was further predicted and shown to negatively interact with circ-CCNB1, which is involved in trophoblast proliferation and invasion. Using bioinformatics tools and subsequent RNA pull-down and dual luciferase assays, we found that miR-223 directly targets seven in absentia homolog-1 (SIAH1) and that upregulation of miR-223 decreased circ-CCNB1-induced SIAH1 expression levels in HTR-8/SVneo cells. Interestingly, upregulation of circ-CCNB1 suppressed trophoblast proliferation and invasion through inhibition of CCNB1 nuclear translocation induced by SIAH1. Downregulation of SIAH1 enhanced circ-CCNB1-suppressed CCNB1 nuclear protein expression in trophoblast cells.

CONCLUSION

Circ-CCNB1 served as a modulator of trophoblast proliferation and invasion by sponging miR-223, thus forming a regulatory network of circ-CCNB1/miR-223/SIAH1 in modulating CCNB1 nuclear translocation, which enabled us to elucidate the molecular mechanisms involved in normal embryo implantation or in SA.

ZBED1 Regulates Genes Important for Multiple Biological Processes of the Placenta

The transcription factor ZBED1 is highly expressed in trophoblast cells, but its functions in the processes of trophoblast and placental biology remain elusive. Here, we characterized the role of ZBED1 in trophoblast cell differentiation using an in vitro BeWo cell model. We demonstrate that ZBED1 is enhanced in its expression early after forskolin-induced differentiation of BeWo cells and regulates many of the genes that are differentially expressed as an effect of forskolin treatment. Specifically, genes encoding markers for the differentiation of cytotrophoblast into syncytiotrophoblast and factors essential for trophoblast cell fusion and invasion were negatively regulated by ZBED1, indicating that ZBED1 might be important for maintaining a steady pool of cytotrophoblast cells. In addition, ZBED1 affected genes involved in the regulation of trophoblast cell survival and apoptosis, in agreement with the observed increase in apoptosis upon knockdown of ZBED1 in forskolin-treated BeWo cells. In addition, genes implicated in the differentiation, recruitment, and function of innate immune cells by the placenta were affected by ZBED1, further suggesting a role for this protein in the regulation of maternal immune tolerance. In conclusion, our study implicates ZBED1 in major biological processes of placental biology.

A Systematic Review to Guide Future Efforts in the Determination of Genetic Causes of Pregnancy Loss

Background: Pregnancy loss is the most common obstetric complication occurring in almost 30% of conceptions overall and in 12–14% of clinically recognized pregnancies. Pregnancy loss has strong genetic underpinnings, and despite this consensus, our understanding of its genetic causes remains limited. We conducted a systematic review of genetic factors in pregnancy loss to identify strategies to guide future research.

Methods: To synthesize data from population-based association studies on genetics of pregnancy loss, we searched PubMed for relevant articles published between 01/01/2000-01/01/2020. We excluded review articles, case studies, studies with limited sample sizes to detect associations (N &lt; 4), descriptive studies, commentaries, and studies with non-genetic etiologies. Studies were classified based on developmental periods in gestation to synthesize data across various developmental epochs.

Results: Our search yielded 580 potential titles with 107 (18%) eligible after title/abstract review. Of these, 54 (50%) were selected for systematic review after full-text review. These studies examined either early pregnancy loss (n = 9 [17%]), pregnancy loss &gt;20 weeks' gestation (n = 10 [18%]), recurrent pregnancy loss (n = 32 [59%]), unclassified pregnancy loss (n = 3 [4%]) as their primary outcomes. Multiple genetic pathways that are essential for embryonic/fetal survival as well as human development were identified.

Conclusion: Several genetic pathways may play a role in pregnancy loss across developmental periods in gestation. Systematic evaluation of pregnancy loss across developmental epochs, utilizing whole genome sequencing in families may further elucidate causal genetic mechanisms and identify other pathways critical for embryonic/fetal survival.

Loss of miR-29a impairs decidualization of endometrial stromal cells by TET3 mediated demethylation of Col1A1 promoter

A conceptual framework for understanding abnormal endometrial decidualization, with considerable significance for the diagnosis and treatment of abnormal decidualization-related changes in non-receptive endometrium in implantation failure during early pregnancy is very important. Here, we found the expression levels of miR-29a in endometrial tissues were associated with the menstrual phases and pregnancy outcome. Inhibition of miR-29a led to decreased decidualization of endometrial stromal cells (ESCs) in vitro, whereas Tet methylcytosine dioxygenase 3 (TET3) and its potential demethylation target, the collagen type I alpha 1 chain (Col1A1), were restored. The binding capacity of TET3 to the Col1A1 promoter could be enhanced by the inhibition of miR-29a. Finally, deletion of TET3 rescued the inhibitory effect of the miR-29a antagomir on the proliferation of decidualized ESCs in vitro and embryo implantation in vivo. Thus, loss of miR-29a causes implantation failure because of the limitation of ESCs decidualization-related changes in non-receptive endometrium during early pregnancy.

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Loss of miR-29a inhibits decidualization of ESCs

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TET3 demethylates the Col1A1 promoter

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Loss of miR-29a enhances the binding capacity of TET3 to the Col1A1 promoter

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Loss of miR-29a suppresses embryo implantation during early pregnancy in mice

Steroid hormones and first trimester vascular remodeling

Successful implantation and placentation require neoangiogenesis and the remodeling of the uterine spiral arteries. Progesterone and estradiol control various of the placental functions, but their role in vascular remodeling remains controversial. Therefore, this chapter aims to summarize the current knowledge regarding the role of steroid hormones in the uteroplacental vascular remodeling during the first trimester of gestation.

ERα, A Key Target for Cancer Therapy: A Review

Estrogen receptor α (ERα) is closely associated with both hormone-dependent and hormone-independent tumors, and it is also essential for the development of these cancers. The functions of ERα are bi-faceted; it can contribute to cancer progression as well as cancer inhibition. Therefore, understanding ERα is vital for the treatment of those cancers that are closely associated with its expression. Here, we will elaborate on ERα based on its structure, localization, activation, modification, and mutation. Also, we will look at co-activators of ERα, elucidate the signaling pathway activated by ERα, and identify cancers related to its activation. A comprehensive understanding of ERα could help us to find new ways to treat cancers.