Establishment Of Pregnancy Research Articles

Cytochrome c oxidase IV isoform 1 (COX4-1) regulates the proliferation, migration and invasion of trophoblast cells via modulating mitochondrial function

IntroductionSpontaneous miscarriage is a common complication of early pregnancy. Previous studies have shown that mitochondrial function plays an important role in establishment of a successful pregnancy. Cytochrome c oxidase subunit 4 isoform 1 (COX4I1), a component of electron transport chain complex Ⅳ, is required for coupling the rate of ATP production to energetic requirements. However, there is very limited research on its role in trophoblast biology and how its dysfunction may contribute to spontaneous miscarriage. MethodsPlacental villi (7–10 weeks gestational age) collected from either induced termination of pregnancy or after spontaneous miscarriage were examined for expression of COX4I1. COX4I1 was knocked down by siRNA transfection of primary isolates of EVT cells. Real-time cell analysis (RTCA) and 5-Ethynyl-2′-deoxyuridine (EdU) were used to detect changes in proliferation ability after COX4I1 knockdown of EVT cells. Migration and invasion indices were determined by RTCA. Mitochondrial morphology was observed via MitoTracker staining. Oxidative phosphorylation, ATP production, and glycolysis in COX4I1-deficient cells and controls were assessed by a cellular energy metabolism analyzer (Seahorse). ResultsIn placental villous tissue, COX4I1 expression was significantly decreased in the spontaneous miscarriage group. Knockdown of COX4I1 inhibited EVT cell proliferation, increased the migration and invasion ability and mitochondrial fusion of EVT cells. Mitochondrial respiration and glycolysis were impaired in COX4I1-deficient EVT cells. Knockdown of MMP1 could rescue the increased migration and invasion induced by COX4I1 silencing. DiscussionLow expression of COX4I1 leads to mitochondrial dysfunction in EVT, resulting in altered trophoblast function, and ultimately to pregnancy loss.

Progesterone Supplementation Improves the Maternal Syndrome of Superimposed Preeclampsia in the Dahl Salt Sensitive Rats

Introduction: Preeclampsia (PE) is characterized by new onset of hypertension after 20 weeks of gestation. It affects 5-7% of all pregnancies in the U.S., and is associated with reduced fetal weight, inflammation and hypertension (HTN). Importantly, 30% of HTN disorders in pregnancy are caused by chronic HTN that is present prior to pregnancy which increases the risk of superimposed PE (SIPE). The mechanisms responsible for the pathogenesis of PE and SIPE are unclear and currently the only treatment is early delivery of the fetus. Progesterone is important for the establishment and maintenance of pregnancy. We have previously shown that progesterone supplementation with 17-hydroxyprogesterone caproate (17-OHPC) improves inflammation, fetal weight and blood pressure in the preclinical RUPP rat model of PE, however the mechanism for this in SIPE is still unknown. Hypothesis: This study was designed to test the hypothesis that 17-OHPC reduces inflammation while improving maternal blood pressure in the preclinical pregnant Dahl Salt Sensitive (DS) rat model of SIPE. Methods: 17-OHPC (3.32mg/kg) or vehicle (Saline) was administrated intraperitoneally on gestation day (GD) 15 to normal pregnant (NP) Sprague-Dawley (SD) and pregnant Dahl Salt Sensitive (DS) rats. On GD 18, Uterine Artery Resistance Index (UARI) was measured by Vevo Doppler Ultrasound and carotid catheters were inserted. On GD 19, mean arterial blood pressure (MAP) and samples were collected. All data are expressed as mean ± standard error means (SEM). Results: MAP was 105±5 mmHg in SD+ Saline rats (n=7) and 105±4 mmHg in SD+17-OHPC rats (n=4), 137±3 mmHg in DS + Saline rats (p<0.05, n=11), which improved to 125±4 mmHg in DS+17-OHPC rats (p<0.05, n=7). Pup and Placenta weights were 2.1± 0.1 g, 0.6 ± 0.1 g in SD + saline rats and significantly reduced to 1.4±0.1 g, 0.5±0.1 g in DS+ Saline rats (p<0.05). Neither placental weight nor pup weight was affected by 17-OHPC. UARI was 0.5 ±0.1 in SD+ Saline rats (n=6) and 0.5 ±0.1 in in SD+17-OHPC (n=4), 0.7±0.1 in DS+Saline rats (n=6, p<0.05), which reduced to 0.5±0.1 in DS+17-OHPC (n=7, p<0.05). TNF-alpha levels were 3.0±1.0 pg/mL in SD+ Saline rats, 11.0±1.2 in DS + Saline rats, which reduced to 4.1±1.6 in DS+17-OHPC (n=4, p<0.05). Importantly, circulating and placental CD4+ T cells were 9.3±3.7 % Gate and 6.4± 1.6 % Gate in SD+ Saline rats (n=4), 38.9 ±2.9 % Gate and 33.1±4.3 % Gate in DS + Saline rats (n=6), which significantly reduced to 26.3 ± 0.1 % Gate and 3.4±1.2 % Gate in DS + 17-OHPC. Conclusion: Collectively, our findings demonstrate that 17-OHPC reduces inflammation and hypertension in the Dahl Salt Sensitive rat model of SIPE. Supported by NIH P20GM121334. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Placenta: an old organ with new functions.

The transition from oviparity to viviparity and the establishment of feto-maternal communications introduced the placenta as the major anatomical site to provide nutrients, gases, and hormones to the developing fetus. The placenta has endocrine functions, orchestrates maternal adaptations to pregnancy at different periods of pregnancy, and acts as a selective barrier to minimize exposure of developing fetus to xenobiotics, pathogens, and parasites. Despite the fact that this ancient organ is central for establishment of a normal pregnancy in eutherians, the placenta remains one of the least studied organs. The first step of pregnancy, embryo implantation, is finely regulated by the trophoectoderm, the precursor of all trophoblast cells. There is a bidirectional communication between placenta and endometrium leading to decidualization, a critical step for maintenance of pregnancy. There are three-direction interactions between the placenta, maternal immune cells, and the endometrium for adaptation of endometrial immune system to the allogeneic fetus. While 65% of all systemically expressed human proteins have been found in the placenta tissues, it expresses numerous placenta-specific proteins, whose expression are dramatically changed in gestational diseases and could serve as biomarkers for early detection of gestational diseases. Surprisingly, placentation and carcinogenesis exhibit numerous shared features in metabolism and cell behavior, proteins and molecular signatures, signaling pathways, and tissue microenvironment, which proposes the concept of "cancer as ectopic trophoblastic cells". By extensive researches in this novel field, a handful of cancer biomarkers has been discovered. This review paper, which has been inspired in part by our extensive experiences during the past couple of years, highlights new aspects of placental functions with emphasis on its immunomodulatory role in establishment of a successful pregnancy and on a potential link between placentation and carcinogenesis.

Effects of Regulating Hippo and Wnt on the Development and Fate Differentiation of Bovine Embryo.

The improvement of in vitro embryo development is a gateway to enhance the output of assisted reproductive technologies. The Wnt and Hippo signaling pathways are crucial for the early development of bovine embryos. This study investigated the development of bovine embryos under the influence of a Hippo signaling agonist (LPA) and a Wnt signaling inhibitor (DKK1). In this current study, embryos produced in vitro were cultured in media supplemented with LPA and DKK1. We comprehensively analyzed the impact of LPA and DKK1 on various developmental parameters of the bovine embryo, such as blastocyst formation, differential cell counts, YAP fluorescence intensity and apoptosis rate. Furthermore, single-cell RNA sequencing (scRNA-seq) was employed to elucidate the in vitro embryonic development. Our results revealed that LPA and DKK1 improved the blastocyst developmental potential, total cells, trophectoderm (TE) cells and YAP fluorescence intensity and decreased the apoptosis rate of bovine embryos. A total of 1203 genes exhibited differential expression between the control and LPA/DKK1-treated (LD) groups, with 577 genes upregulated and 626 genes downregulated. KEGG pathway analysis revealed significant enrichment of differentially expressed genes (DEGs) associated with TGF-beta signaling, Wnt signaling, apoptosis, Hippo signaling and other critical developmental pathways. Our study shows the role of LPA and DKK1 in embryonic differentiation and embryo establishment of pregnancy. These findings should be helpful for further unraveling the precise contributions of the Hippo and Wnt pathways in bovine trophoblast formation, thus advancing our comprehension of early bovine embryo development.

Uterine macrophages and NK cells exhibit population and gene-level changes after implantation but maintain pro-invasive properties.

Prior to pregnancy, hormonal changes lead to cellular adaptations in the endometrium allowing for embryo implantation. Critical for successful pregnancy establishment, innate immune cells constitute a significant proportion of uterine cells prior to arrival of the embryo and throughout the first trimester in humans and animal models. Abnormal uterine immune cell function during implantation is believed to play a role in multiple adverse pregnancy outcomes. Current work in humans has focused on uterine immune cells present after pregnancy establishment, and limited in vitro models exist to explore unique functions of these cells. With single-cell RNA-sequencing (scRNAseq), we comprehensively compared the human uterine immune landscape of the endometrium during the window of implantation and the decidua during the first trimester of pregnancy. We uncovered global and cell-type-specific gene signatures for each timepoint. Immune cells in the endometrium prior to implantation expressed genes associated with immune metabolism, division, and activation. In contrast, we observed widespread interferon signaling during the first trimester of pregnancy. We also provide evidence of specific inflammatory pathways enriched in pre- and post-implantation macrophages and natural killer (NK) cells in the uterine lining. Using our novel implantation-on-a-chip (IOC) to model human implantation ex vivo, we demonstrate for the first time that uterine macrophages strongly promote invasion of extravillous trophoblasts (EVTs), a process essential for pregnancy establishment. Pre- and post-implantation uterine macrophages promoted EVT invasion to a similar degree as pre- and post-implantation NK cells on the IOC. This work provides a foundation for further investigation of the individual roles of uterine immune cell subtypes present prior to embryo implantation and during early pregnancy, which will be critical for our understanding of pregnancy complications associated with abnormal trophoblast invasion and placentation.

Establishment of Murine Pregnancy Requires the Promyelocytic Leukemia Zinc Finger Transcription Factor.

Using an established human primary cell culture model, we previously demonstrated that the promyelocytic leukemia zinc finger (PLZF) transcription factor is a direct target of the progesterone receptor (PGR) and is essential for progestin-dependent decidualization of human endometrial stromal cells (HESCs). These in vitro findings were supported by immunohistochemical analysis of human endometrial tissue biopsies, which showed that the strongest immunoreactivity for endometrial PLZF is detected during the progesterone (P4)-dominant secretory phase of the menstrual cycle. While these human studies provided critical clinical support for the important role of PLZF in P4-dependent HESC decidualization, functional validation in vivo was not possible due to the absence of suitable animal models. To address this deficiency, we recently generated a conditional knockout mouse model in which PLZF is ablated in PGR-positive cells of the mouse (Plzf d/d). The Plzf d/d female was phenotypically analyzed using immunoblotting, real-time PCR, and immunohistochemistry. Reproductive function was tested using the timed natural pregnancy model as well as the artificial decidual response assay. Even though ovarian activity is not affected, female Plzf d/d mice exhibit an infertility phenotype due to an inability of the embryo to implant into the Plzf d/d endometrium. Initial cellular and molecular phenotyping investigations reveal that the Plzf d/d endometrium is unable to develop a transient receptive state, which is reflected at the molecular level by a blunted response to P4 exposure with a concomitant unopposed response to 17-β estradiol. In addition to a defect in P4-dependent receptivity, the Plzf d/d endometrium fails to undergo decidualization in response to an artificial decidual stimulus, providing the in vivo validation for our earlier HESC culture findings. Collectively, our new Plzf d/d mouse model underscores the physiological importance of the PLZF transcription factor not only in endometrial stromal cell decidualization but also uterine receptivity, two uterine cellular processes that are indispensable for the establishment of pregnancy.

99 Diversity of vaginal bacteria in lactating dairy cattle on pregnancy establishment

Abstract Establishment and maintenance of pregnancy has a substantial economic impact within the dairy industry each year. Recent research has indicated a potential role of the reproductive microbiome on impacting pregnancy status as a result of hormone concentrations and breeding strategies. However, the association between alpha (within sample metric) and beta (between samples metric) bacterial diversity with pregnancy establishment has not been extensively evaluated in dairy cattle. Thereby, the objective of this study was to analyze vaginal bacterial diversity in lactating dairy cows 1) between day of artificial insemination (AI; day 0) and maternal recognition of pregnancy (MRP; d 18), and 2) between resulting Open and Pregnant females. Lactating Holstein dairy cows (n = 53) were sampled of day of AI and day of MRP. Pregnancy determination occurred on day 32 via transrectal ultrasonography. Sterile swabs were inserted into the vagina, rotated eight times against the vaginal wall, and stored in sterile microcentrifuge tubes at -80°C. Swab samples were utilized for subsequent bacterial diversity analyses targeting the V4 hypervariable region of the 16S rRNA gene. Cows underwent transrectal ultrasonography on gestational day 32 for pregnancy determination. Sample quality was determined by FastQC before being processed with the qiime2 pipeline for taxonomic classification. Alpha diversity metrics were analyzed with Kruskal-Wallis and beta diversity was measured utilizing PERMANOVA in the qiime2 pipeline. At day 32 of gestation, the pregnancy rate was 47.2%. According to Faith’s Phylogenetic Diversity metric for alpha diversity, there was no significant difference in diversity richness (i.e., number of different bacterial species within a sample) between day of AI and MRP or between cows diagnosed as Open or Pregnant (P >0.05). Pielou’s Evenness metric (i.e., distribution or balance of bacterial species within a sample) for alpha diversity indicated greater diversity within samples at day of AI compared with day of MRP (P = 0.02). Shannon’s diversity index metric (i.e., richness and evenness within a sample) for alpha diversity also indicated greater diversity at day of AI compared with day of MRP (P = 0.04). However, there was no difference between resulting Open and Pregnant females for Pielou’s or Shannon’s metrics (P > 0.05). Distinctions between samples (beta diversity) were compared utilizing pairwise comparisons of the unweighted and weighted Unifrac distance metrics. Specifically, day of AI indicated lower diversity compared with day of MRP for both metrics (P < 0.01). However, upon comparisons of Open and Pregnant status, there was no difference between samples for unweighted or weighted Unifrac distances (P > 0.05). Based on these results, bacterial diversity within and between vaginal samples appear to shift between day of AI and day of MRP. Additional studies are needed to elucidate the mechanisms altering bacterial diversity during early gestation in lactating dairy cows.

9 Randel Lecture: In Vivo investigation of pregnancy Physiology

Abstract Pregnancy in any mammal requires the integration of three distinct compartments; the maternal, placental and fetal compartments. Compromised function of any of the three compartments can result in suboptimal pregnancy outcomes, including increased morbidity and mortality at delivery, reduced livestock production efficiency and adult-onset of metabolically-related disease in humans. To accurately understand the progression of both normal and compromised pregnancies, therefore, requires the simultaneous assessment of all three compartments, which for most species is not technically feasible. Consequently, over the past 60 yr the pregnant sheep has been used extensively for in vivo investigation of pregnancy physiology. The ability to place indwelling catheters, within both maternal and fetal vessels, allows the simultaneous steady-state assessment of uterine and umbilical blood flows, hormone secretion, and nutrient uptake and utilization of nutrients by each of the three compartments, under non-stressed and non-anesthetized conditions. This has provided unrivalled insight into the physiology of pregnancy, and the realization that the placenta is a highly metabolic tissue, utilizing the majority of oxygen and glucose taken up by the uterus. However, the deficit in studying pregnant sheep is the lack of genetic models, readily available in rodents, that could help define specific gene function during pregnancy. Consequently, we developed in vivo lentiviral-mediated RNA interference (RNAi) methods to specifically alter the abundance of specific gene transcripts/proteins within the placenta, beginning at 9 d of gestation (dGA). Our lentiviral-mediated approach limits the RNAi to the trophectoderm derivatives of the placenta. Initially we used this approach to determine the importance of PRR15 and LIN28 during the establishment of pregnancies, but turned our efforts towards combining in vivo RNAi with steady-state physiological assessments during late gestation to examine the function of genes involved in placental nutrient transport (SLC2A3) and placenta derived hormones (CSH). By creating a placental deficiency in SLC2A3, not only was the fetus smaller and hypoglycemic at mid-gestation, but by interfering with placental glucose uptake, maternal hormone concentrations were also impacted, yet near-term, a distinctly different phenotype was present. For the placental hormone CSH (a.k.a. placental lactogen), CSH RNAi not only impacts placental and fetal growth, but also reductions in uterine blood flow, nutrient fluxes to the fetus, and produces an altered hormonal environment. Combining these methodological approaches provides new and often unexpected insights into the physiological integration of the maternal, placental and fetal compartments. Supported by NIH-NICHD grants HD093701 and HD094952.

121 Unraveling the biology of bovine conceptus elongation

Abstract The establishment of pregnancy is a well-regulated process that involves the development of a viable blastocyst, conceptus elongation, maternal recognition of pregnancy, implantation, and the onset of placentation. Pregnancy loss is a major factor limiting reproductive efficiency in livestock species. In cattle, most embryonic losses occur during the first month of gestation. The genetic and epigenetic regulation of embryonic and placental development in ruminants is still poorly understood. To investigate the transcriptome profile of the bovine conceptus during elongation, Angus heifers (n = 8) were superovulated and bred using semen from a proven high-fertility Bos indicus sire. Heifers were flushed on d 14 of gestation using a standard nonsurgical flushing technique. Recovered conceptuses were individually photographed and snap-frozen for total RNA extraction and bulk mRNA sequencing. Recovered conceptuses were classified based on size into ovoid (0.2 – 5mm; n = 6), tubular (<15 mm; n = 7), or filamentous (>16 mm; n = 7). Differentially expressed genes (DEG: FDR < 0.05) were determined using DESeq2 analysis and were functionally annotated using DAVID. The most pronounced transcriptomic changes were identified between the ovoid and tubular stages, with 5,937 DEGs (2,913 upregulated and 3,024 downregulated) and affected pathways were primarily involved in ribosome assembly and rRNA processing. There were 3,966 DEGs (2,069 upregulated and 1,897 downregulated) between the ovoid and filamentous stages, and the most significant pathways were involved in protein translation, embryonic development, and cell cycle. The transition between tubular to filamentous presented 1,435 DEGs (775 upregulated and 660 downregulated) and significant pathways were involved in protein degradation, cell division, cell cycle, protein stabilization, and mRNA splicing. Our findings indicate that the greatest alterations in the transcriptome occur precisely at the initiation of elongation, suggesting that the bovine conceptus undergoes major structural changes at the outset of this process. This major shift in gene expression is presumed to be necessary to support the subsequent exponential growth phase of elongation, required for maternal recognition of pregnancy.

Meta-analysis to determine efficacy of colony-stimulating factor 2 for improving pregnancy success after embryo transfer in cattle

Results have been inconsistent as to whether addition of colony stimulating factor 2 (CSF2) to culture medium improves embryo competence for establishment of pregnancy in cattle and humans. The purpose of the current study was to use all available experiments in cattle concerning effects of CSF2 on pregnancy success after transfer into recipient cattle. The approach was to perform a meta-analysis of all published data sets as well as data from an unpublished experiment described for the first time here. Meta-analysis failed to support the hypothesis that addition of CSF2 to embryo culture medium improves competence of bovine blastocysts to increase pregnancy or calving rates after transfer into recipient females. Thus, its general use as a culture medium additive to increase pregnancy success after embryo transfer is not recommended.

Protective role of complement factor H against the development of preeclampsia.

Pregnancy is an immunologically regulated, complex process. A tightly controlled complement system plays a crucial role in the successful establishment of pregnancy and parturition. Complement inhibitors at the feto-maternal interface are likely to prevent inappropriate complement activation to protect the fetus. In the present study, we aimed to understand the role of Factor H (FH), a negative regulator of complement activation, in normal pregnancy and in a model of pathological pregnancy, i.e. preeclampsia (PE). The distribution and expression of FH was investigated in placental tissues, various placental cells, and in the sera of healthy (CTRL) or PE pregnant women via immunohistochemistry, RT-qPCR, ELISA, and Western blot. Our results showed a differential expression of FH among the placental cell types, decidual stromal cells (DSCs), decidual endothelial cells (DECs), and extravillous trophoblasts (EVTs). Interestingly, FH was found to be considerably less expressed in the placental tissues of PE patients compared to normal placental tissue both at mRNA and protein levels. Similar results were obtained by measuring circulating FH levels in the sera of third trimester CTRL and PE mothers. Syncytiotrophoblast microvesicles, isolated from the placental tissues of PE and CTRL women, downregulated FH expression by DECs. The present study appears to suggest that FH is ubiquitously present in the normal placenta and plays a homeostatic role during pregnancy.

MUC1 regulation in the left and right uterine horns and conceptus trophectoderm during the peri-implantation period of dromedary camel

Pregnancy maintenance in dromedary camels poses significant challenges, including early embryonic loss in the left uterine horn (LH) and unsuccessful pregnancy in the right uterine horn (RH), suggesting a potential asynchrony between conceptus signaling and uterine receptivity. The transition of the uterine epithelium from a pre-receptive to a receptive state requires a delicate balance of adhesion-promoting and anti-adhesion molecules. Mucin-1 (MUC1) acts as an anti-adhesive molecule on the uterine luminal (LE) and glandular (GE) epithelium. Downregulation of MUC1 is believed to be crucial for successful embryo attachment in various mammals. This study aimed to investigate the temporospatial expression of MUC1 in the LH and RH on Days 8, 10, and 12 pregnant dromedaries and their conceptuses. Quantitative real-time polymerase chain reaction (qrt-PCR), Western blot analysis, immunohistochemistry, and immunofluorescence techniques were employed to assess MUC1 expression at the mRNA and protein levels. The results demonstrated a reduction in MUC1 mRNA expression on Day 8, then increased on Day 10, followed by a decrease on Day 12 in LH. While the RH exhibited progressive increases, peaking on Day 12. However, MUC1 expression constantly exhibited higher levels in RH than in LH in all days. Two bands were detected at 150-kDa and 180-kDa, with the highest intensity observed on Day 10. Spatially, MUC1 was localized in the apical, cytoplasmic, and lumen of uterine glands only. MUC1 was barely detectable on Day 8 but gradually increased on Days 10 and 12 in both horns. Likewise, the RH exhibited higher MUC1 signals than the LH on Days 10 and 12. In the conceptuses, MUC1 mRNA increased on Day 8, peaked on Day 10, and declined on Day 12. Notably, MUC1 protein was detected in both the trophectoderm and endoderm, with high expression observed on Day 10 and reduced by Day 12. In conclusion, the decrease in MUC1 expression on Day 8 in the LH may be associated with maternal recognition of pregnancy (MRP), and the increase on Day 10 may related to embryo protection and movement, while the subsequent decrease on Day 12 could be linked to the embryo attachment and preparation for the implantation. Conversely, the increase of MUC1 in the RH implies a role in the anti-adhesion mechanism. These findings contribute to understanding MUC1's involvement in reproductive processes and provide insights into the complex mechanisms underlying successful pregnancy establishment and maintenance in dromedary camels.

Exosomes as modulators of embryo implantation.

Exosomes, known as extracellular vehicles (EVs), are found in biological fluids. They have the capability to carry and transfer signaling molecules, such as nucleic acids and proteins, facilitating intercellular communication and regulating the gene expression profile in target cells. EVs have the potential to be used as biomarkers in diagnosis, prognosis and also as feasible therapeutic targets. The available evidence suggests that exosomes play critical roles in the reproductive system, particularly during implantation, which is widely recognized as a crucial step in early pregnancy. A proper molecular dialogue between a high-quality embryo and a receptive endometrium is essential for the establishment of a normal pregnancy. This review focuses on the key role of exosomes originated from various sources, including the embryo, seminal fluid, and uterus fluid, based on the available evidence. It explores their potential applications as a novel approach in assisted reproductive technologies (ART).

Transcriptomic analysis of bovine endometrial epithelial cells in response to interferon tau and hormone stimulation.

The embryonic loss during early stage of gestation is one of the major causes of infertility for domestic ruminants, causing huge economic losses to pasture. Maternal recognition of pregnancy and implantation are the crucial process for determining the successful establishment and development of pregnancy in cattle. The research on molecular mechanisms of pregnancy recognition will facilitate illustrating the complex process of pregnancy establishment and help to improve pregnancy outcomes. In this study, we performed transcriptomic analysis of primary bovine endometrial epithelial cells (BEND) with or without IFNT and hormones intervention through RNA sequencing. We eventually identified 608 differentially expressed genes (DEGs) including 409 up-regulated genes and 199 down-regulated genes in IFNT and hormones-treated group compared with control group. Gene Ontology (GO) enrichment analysis demonstrated that the majority of DEGs were implicated in immune system process, response to external stimulus, response to cytokine, regulation of response to stress. Results from KEGG analysis showed a significant enrichment of NOD-like receptor signaling pathway, antigen processing and presentation, necroptosis, oxidative phosphorylation, RIG-I-like receptor signaling pathway. Additionally, a set of promising candidate genes, including (USP18, STAT1, PSMB8, IFIH1, MX2, IFI44, DHX58, CASP8, DRAM1, CXCR4), were characterized by constructing an integrated interaction network. Specifically, the mRNA expression of HOXA11, PTGS1 and PTGS2 were remarkably suppressed by silencing DRAM1 under IFNT and hormone administration, thus speculating that DRAM1 might play a crucial role in early pregnancy by regulating endometrial function. The results of this study depicted a relatively comprehensive transcriptional profiles of BEND in response to IFNT and hormones, which contributes to a better understanding of gene interaction network and underlying regulatory mechanisms in endometrium of ruminants during early pregnancy.

Role of immune cells in the establishment of implantation and maintenance of pregnancy and immunomodulatory therapies for patients with repeated implantation failure and recurrent pregnancy loss.

Immune cells play an important role in the establishment of pregnancy, and abnormalities in the immune system can cause implantation failure and miscarriage. Previous papers have been summarized and the role of immune cells in reproduction is reviewed. The immune environment in the uterus changes drastically from before implantation to after pregnancy to maintain pregnancy. In allogeneic pregnancies, immature dendritic cells (DCs) that induce immune tolerance from outside the uterus flow into the uterus, and mature DCs that remain in the uterus express programmed cell death ligand 2, which suppresses the immune response. Macrophages are classified into M1-macrophages, which induce inflammation, and M2-macrophages, which suppress inflammation; M1-macrophages are required for luteinization, and M2-macrophages induce the differentiation of endometrial epithelial cells to enable implantation. Regulatory T cells, which suppress rejection, are essential for the implantation and maintenance of allogeneic pregnancies. Implantation failure and fetal loss are associated with decreased numbers or qualitative abnormalities of DCs, macrophages, and regulatory T cells. The clinical usefulness of immunomodulatory therapies in patients with repeated implantation failure and recurrent pregnancy loss has been reported. The provision of individualized medical care in cases of implantation failure or miscarriage may improve clinical outcomes.

Fibronectin mediates activin A-promoted human trophoblast migration and acquisition of endothelial-like phenotype

BackgroundDuring human early placentation, a proportion of extravillous trophoblasts (EVTs) migrate to the maternal decidua, differentiating into endovascular EVTs to remodel spiral arteries and ensure the establishment of blood circulation at the maternal-fetal interface. Inadequate EVT migration and endovascular differentiation are closely associated with adverse pregnancy outcomes such as miscarriage. Activin A and fibronectin are both secretory molecules abundantly expressed at the maternal-fetal interface. Activin A has been reported to regulate EVT biological functions. However, whether fibronectin mediates activin A-promoted EVT migration and acquisition of endothelial-like phenotype as well as the underlying molecular mechanisms remain unknown. Additionally, the role of fibronectin in pregnancy establishment and maintenance warrants further investigation.MethodsPrimary and immortalized (HTR8/SVneo) human EVTs were used as in vitro study models. Cultured human first-trimester chorionic villous explants were utilized for ex vivo validation. A local fibronectin knockdown model in ICR mouse uteri, achieved by nonviral in vivo transfection with small interfering RNA (siRNA) targeting fibronectin 1 (si-Fn1), was employed to explore the roles of fibronectin in the establishment and maintenance of early pregnancy.ResultsOur results showed that activin A treatment significantly induced fibronectin 1 (FN1) mRNA expression and fibronectin protein production, which is essential for human trophoblast migration and endothelial-like tube formation. Both basal and activin A-upregulated fibronectin expression were abolished by the TGF-β type I receptor inhibitor SB431542 or siRNA-mediated knockdown of activin receptor-like kinase (ALK4) or SMAD4. Moreover, activin A-increased trophoblast migration and endothelial-like tube formation were attenuated following the depletion of fibronectin. Fibronectin knockdown via intrauterine siRNA administration reduced CD31 and cytokeratin 8 (CK8) expression at the maternal-fetal interface, resulting in a decrease in the number of implantation sites and embryos.ConclusionsOur study demonstrates that activin A promotes trophoblast cell migration and acquisition of endothelial-like phenotype via ALK4-SMAD2/3-SMAD4-mediated fibronectin upregulation. Furthermore, through a local fibronectin knockdown model in mouse uteri, we found that the absence of fibronectin at the maternal-fetal interface impedes endovascular migration of trophoblasts and decidual vascularization, thereby interfering with early embryo implantation and the maintenance of pregnancy. These findings provide novel insights into placental development during early pregnancy establishment and contribute to the advancement of therapeutic approaches for managing pregnancy complications related to trophoblast dysfunction.

HB-EGF-loaded nanovesicles enhance trophectodermal spheroid attachment and invasion.

The ability of trophectodermal cells (outer layer of the embryo) to attach to the endometrial cells and subsequently invade the underlying matrix are critical stages of embryo implantation during successful pregnancy establishment. Extracellular vesicles (EVs) have been implicated in embryo-maternal crosstalk, capable of reprogramming endometrial cells towards a pro-implantation signature and phenotype. However, challenges associated with EV yield and direct loading of biomolecules limit their therapeutic potential. We have previously established generation of cell-derived nanovesicles (NVs) from human trophectodermal cells (hTSCs) and their capacity to reprogram endometrial cells to enhance adhesion and blastocyst outgrowth. Here, we employed a rapid NV loading strategy to encapsulate potent implantation molecules such as HB-EGF (NVHBEGF). We show these loaded NVs elicit EGFR-mediated effects in recipient endometrial cells, activating kinase phosphorylation sites that modulate their activity (AKT S124/129, MAPK1 T185/Y187), and downstream signalling pathways and processes (AKT signal transduction, GTPase activity). Importantly, they enhanced target cell attachment and invasion. The phosphoproteomics and proteomics approach highlight NVHBEGF-mediated short-term signalling patterns and long-term reprogramming capabilities on endometrial cells which functionally enhance trophectodermal-endometrial interactions. This proof-of-concept study demonstrates feasibility in enhancing the functional potency of NVs in the context of embryo implantation.

Endometrial BMP2 Deficiency Impairs ITGB3-Mediated Trophoblast Invasion in Women With Repeated Implantation Failure.

Repeated implantation failure (RIF) leads to a waste of high-quality embryos and remains a challenge in assisted reproductive technology. During early human placentation, the invasion of trophoblast cells into the decidua is an essential step for the establishment of maternal-fetal interactions and subsequent successful pregnancy. Bone morphogenetic protein 2 (BMP2) has been reported to regulate endometrial receptivity and promote trophoblast invasion. However, whether there is dysregulation of endometrial BMP2 expression in patients with RIF remains unknown. Additionally, the molecular mechanisms underlying the effects of BMP2 on human trophoblast invasion and early placentation remain to be further elucidated. Midluteal phase endometrial samples were biopsied from patients with RIF and from routine control in vitro fertilization followed by quantitative polymerase chain reaction and immunoblotting analyses. Human trophoblast organoids, primary human trophoblast cells, and an immortalized trophoblast cell line (HTR8/SVneo) were used as study models. We found that BMP2 was aberrantly low in midluteal phase endometrial tissues from patients with RIF. Recombinant human BMP2 treatment upregulated integrin β3 (ITGB3) in a SMAD2/3-SMAD4 signaling-dependent manner in both HTR8/SVneo cells and primary trophoblast cells. siRNA-mediated integrin β3 downregulation reduced both basal and BMP2-upregulated trophoblast invasion and vascular mimicry in HTR8/SVneo cells. Importantly, shRNA-mediated ITGB3 knockdown significantly decreased the formation ability of human trophoblast organoids. Our results demonstrate endometrial BMP2 deficiency in patients with RIF. ITGB3 mediates both basal and BMP2-promoted human trophoblast invasion and is essential for early placentation. These findings broaden our knowledge regarding the regulation of early placentation and provide candidate diagnostic and therapeutic targets for RIF clinical management.

CAMP regulates the progesterone receptor gene expression through the protein kinase A pathway during decidualization in human immortalized endometrial stromal cells

Decidualization, a crucial process for successful pregnancy establishment and maintenance, involves endometrial stromal cell differentiation. This process is orchestrated by estradiol (E2), progesterone, and other stimuli that increase intracellular cyclic adenosine monophosphate (cAMP) levels. The intracellular progesterone receptor (PR), encoded by the PGR gene, has a key role in decidualization.This study aimed to understand the role of sex steroids and cAMP in regulating PGR expression during the in vitro decidualization of the human immortalized endometrial stromal cell line, T-HESC. We subjected the cells to individual and combined treatments of E2, medroxyprogesterone (MPA), and cAMP. Additionally, we treated cells with PR and estrogen receptor antagonists and a protein kinase A (PKA) inhibitor. We evaluated the expression of PGR isoforms and decidualization-associated genes by RT-qPCR.Our findings revealed that cAMP induced PGR-B and PGR-AB expression by activating the PKA signaling pathway, while MPA downregulated their expression through the PR. Furthermore, downstream genes involved in decidualization, such as those coding for prolactin (PRL), insulin-like growth factor-binding protein-1 (IGFBP1), and Dickkopf-1 (DKK1), exhibited positive regulation via the cAMP-PKA pathway. Remarkably, MPA-activated PR signaling induced the expression of IGFBP1 and DKK1 but inhibited that of PRL.In conclusion, we have demonstrated that the PKA signaling pathway induces PGR gene expression during in vitro decidualization of the T-HESC human endometrial stromal cell line. This study has unraveled some of the intricate regulatory mechanisms governing PGR expression during this fundamental process for implantation and pregnancy maintenance.

The recipient metabolome explains the asymmetric ovarian impact on fetal sex development after embryo transfer in cattle.

In cattle, lateral asymmetry affects ovarian function and embryonic sex, but the underlying molecular mechanisms remain unknown. The plasma metabolome of recipients serves to predict pregnancy after embryo transfer (ET). Thus, the aim of this study was to investigate whether the plasma metabolome exhibits distinct lateral patterns according to the sex of the fetus carried by the recipient and the active ovary side (AOS), i.e., the right ovary (RO) or the left ovary (LO). We analyzed the plasma of synchronized recipients by 1H+NMR on day 0 (estrus, n = 366) and day 7 (hours prior to ET; n = 367). Thereafter, a subset of samples from recipients that calved female (n = 50) or male (n = 69) was used to test the effects of embryonic sex and laterality on pregnancy establishment. Within the RO, the sex ratio of pregnancies carried was biased toward males. Significant differences (P < 0.05) in metabolite levels were evaluated based on the day of blood sample collection (days 0, 7 and day 7/day 0 ratio) using mixed generalized models for metabolite concentration. The most striking differences in metabolite concentrations were associated with the RO, both obtained by multivariate (OPLS-DA) and univariate (mixed generalized) analyses, mainly with metabolites measured on day 0. The metabolites consistently identified through the OPLS-DA with a higher variable importance in projection score, which allowed for discrimination between male fetus- and female fetus-carrying recipients, were hippuric acid, l-phenylalanine, and propionic acid. The concentrations of hydroxyisobutyric acid, propionic acid, l-lysine, methylhistidine, and hippuric acid were lowest when male fetuses were carried, in particular when the RO acted as AOS. No pathways were significantly regulated according to the AOS. In contrast, six pathways were found enriched for calf sex in the day 0 dataset, three for day 7, and nine for day 7/day 0 ratio. However, when the AOS was the right, 20 pathways were regulated on day 0, 8 on day 7, and 13 within the day 7/day 0 ratio, most of which were related to amino acid metabolism, with phenylalanine, tyrosine, and tryptophan biosynthesis and phenylalanine metabolism pathways being identified throughout. Our study shows that certain metabolites in the recipient plasma are influenced by the AOS and can predict the likelihood of carrying male or female embryos to term, suggesting that maternal metabolism prior to or at the time of ET could favor the implantation and/or development of either male or female embryos.