Early Placental Development Research Articles

Gestational Interrelationships among Gut-Metabolism-Transcriptome in Regulating Early Embryo Implantation and Placental Development in Mice.

Decidualization of the uterine endometrium is a critical process for embryo implantation in mammals, primarily occurring on gestational day 8 in pregnant mice. However, the interplay between the maternal gut microbiome, metabolism, and the uterus at this specific time point remains poorly understood. This study employed a multi-omics approach to investigate the metabolic, gut microbiome, and transcriptomic changes associated with early pregnancy (gestational day 8 (E8)) in mice. Serum metabolomics revealed a distinct metabolic profile at E8 compared to controls, with the differential metabolites primarily enriched in amino acid metabolism pathways. The gut microbial composition showed that E8 mice exhibited higher alpha-diversity and a significant shift in beta-diversity. Specifically, the E8 group displayed a decrease in pathogenic Proteobacteria and an increase in beneficial Bacteroidetes and S24-7 taxa. Transcriptomics identified myriads of distinct genes between the E8 and control mice. The differentially expressed genes were enriched in pathways involved in alanine, aspartate, and glutamate metabolism, PI3K-Akt signaling, and the PPAR signaling pathway. Integrative analysis of the multi-omics data uncovered potential mechanistic relationships among the differential metabolites, gut microbiota, and uterine gene expression changes. Notably, the gene Asns showed strong correlations with specific gut S24-7 and metabolite L-Aspartatic acid, suggesting its potential role in mediating the crosstalk between the maternal environment and embryo development during early pregnancy. These findings provide valuable insights into the complex interplay between the maternal metabolome, the gut microbiome, and the uterine transcriptome in the context of early pregnancy, which may contribute to our understanding of the underlying mechanisms of embryo implantation and development.

Neutrophil Dynamics in Early Placental Development: Regulators of trophoblast invasion?

Neutrophil Dynamics in Early Placental Development: Regulators of trophoblast invasion?

Trophoblast Organoids: Capturing the Complexity of Early Placental Development In Vitro

Trophoblast Organoids: Capturing the Complexity of Early Placental Development In Vitro

Unveiling the human fetal-maternal interface during the first trimester: biophysical knowledge and gaps.

The intricate interplay between the developing placenta and fetal-maternal interactions is critical for pregnancy outcomes. Despite advancements, gaps persist in understanding biomechanics, transport processes, and blood circulation parameters, all of which are crucial for safe pregnancies. Moreover, the complexity of fetal-maternal interactions led to conflicting data and methodological variations. This review presents a comprehensive overview of current knowledge on fetal-maternal interface structures, with a particular focus on the first trimester. More in detail, the embryological development, structural characteristics, and physiological functions of placental chorionic plate and villi, fetal membranes and umbilical cord are discussed. Furthermore, a description of the main structures and features of maternal and fetal fluid dynamic exchanges is provided. However, ethical constraints and technological limitations pose still challenges to studying early placental development directly, which calls for sophisticated in vitro, microfluidic organotypic models for advancing our understanding. For this, knowledge about key in vivo parameters are necessary for their design. In this scenario, the integration of data from later gestational stages and mathematical/computational simulations have proven to be useful tools. Notwithstanding, further research into cellular and molecular mechanisms at the fetal-maternal interface is essential for enhancing prenatal care and improving maternal and fetal health outcomes.

Gene expression profile of human placental villous pericytes in the first trimester – An analysis by single-cell RNA sequencing

Mesenchymal cells within theplacental villi play a crucial role in shaping the morphology of branching structures and driving the development of blood vessels. However, the markers and functions of placental villous pericytes (PVPs) as distinct subgroups of placental villous mesenchymal cells, remain unclear. Therefore, in this study, the markers and functions of PVPs were investigated. Single-cell sequencing data from the first-trimester placental villi was obtained and the Seurat tool was used to identify PVP markers. Gene Ontology (GO) analysis of specific genes was performed using the DAVID database. The Cellchat tool was employed to investigate the interaction signals between the PVPs and other cells. Expression of the PVP markers was confirmed using immunofluorescence. Presence of extracellular vesicles in the placental villous mesenchyme and PVPs was examined by transmission electron microscopy. Our findings revealed that renin (REN) and amphiregulin (AREG)-positive fibroblasts in the placental villi specifically expressed several classic pericyte markers. In the first trimester, certain conserved functions of pericytes were observed and they displayed tissue-specific functions such as in the integrin-mediated signaling pathway and extracellular exosomes. Moreover, the placental villous mesenchyme was found to be rich in extracellular vesicles. AREG is specifically transcribed in the first trimester PVPs, however, its protein was located in syncytiotrophoblasts. These insights contribute to a comprehensive understanding of early placental development and offer new therapeutic targets for placenta-derived pregnancy complications.

CREG1 promotes bovine placental trophoblast cells exosome release by targeting IGF2R and participates in regulating organoid differentiation via exosomes transport

BackgroundPlacental exosomes are a kind of intercellular communication media secreted by placental cells during pregnancy, exosomogenesis and release are regulated by many secretory glycoproteins. CREG1 is a kind of secreted glycoprotein widely expressed in various organs and tissues of the body, which inhibits cell proliferation and enhances cell differentiation. The aim of this study was to explore the role of CREG1 in regulating exosomogenesis during the proliferation and differentiation of placental trophoblast cells in early pregnant dairy cows by targeting IGF2R and participating in regulating organoid differentiation via exosomes transport. MethodsMolecular biological methods were firstly used to investigate the expression patterns of CREG1, IGF2R and exosomal marker proteins in early placental development of pregnant dairy cows. Subsequently, the effects of CREG1 on the formation and release of bovine placental trophoblast (BTCs) derived exosomes by targeting IGF2R were investigated. Further, the effects of CREG1 on the change of gene expression patterns along with the transport of exosomes to recipient cells and participate in regulating the differentiation of organoids were explored. ResultsThe expression of CREG1, IGF2R and exosomal marker proteins increased with the increase of pregnancy months during the early evolution of placental trophoblast cells in dairy cows. Overexpression of Creg1 enhanced the genesis and release of exosomes derived from BTCs, while knocking down the expression of Igf2r gene not only inhibited the genesis of exosomes, but also inhibited the genesis and release of exosomes induced by overexpression of CREG1 protein. Interestingly, IGF2R can regulate the expression of CREG1 through reverse secretion. What's more, the occurrence and release of trophoblast-derived exosomes are regulated by CREG1 binding to IGF2R, which subsequently binds to Rab11. CREG1 can not only promote the formation and release of exosomes in donor cells, but also regulate the change of gene expression patterns along with the transport of exosomes to recipient cells and participate in regulating the early development of placenta. ConclusionsOur study confirmed that CREG1 is involved in the exosomogenesis and release of exosomes during the proliferation and differentiation of placental trophoblast cells in early pregnant dairy cows by targeting IGF2R, and is involved in the regulation of organoid differentiation through exosome transport.

Step-by-step protocol for isolating the entire repertoire of human first trimester placental cells

Correct placental development and function are essential for adapting the mother to the ongoing pregnancy and the wellbeing of the growing fetus; however, underlying processes are still poorly understood. Only limited structural and cellular placental features are shared among species hence requiring reliable human in-vitro models. Recently established trophoblast stem cell and organoid models significantly improved placental research; however, the human placenta constitutes a multi-cellular organ with tightly orchestrated, cellular and molecular networks between trophoblasts (TBs) and villous core cells (VCCs) vital for correct placentation. The establishment of co-culture models is accordingly the logical consequence to investigate TB and VCC interactions, but first requires efficient purification of ideally donor-matched placental cell types. We herein present a meticulously-tailored protocol based on four sequential digestion steps (d-steps) with varying enzyme compositions and digestion mode and length, gently releasing cells layer-by-layer from human first trimester placentae (8 – 9th week of gestation). Using immunofluorescence and flow cytometry, we analyzed the tissue fragments and digestion solutions after every d-step and collected data on individual digestion progress as well as cell viability, counts, and specifications. D-step 1 revealed a significantly low viability and was mainly composed of syncytial fragments, extravillous trophoblasts EVTs, and maternal leukocytes. D-step 2 and 3, comprising high viability predominantly contained TBs (90 – 99 %) with a significant enrichment of EVTs in d-step 2 and an almost pure villous cytotrophoblast (vCTB) population in d-step 3. D-step 4 finally enabled isolating fetal VCCs consisting of endothelial cells, fibroblasts, and Hofbauer cells. Interestingly, maternal leukocytes were detected in d-step 1 and 2 but completely absent from d-step 3 and 4 revealing pure fetal cell populations. In sum, we present a detailed guideline for stepwise isolating selected placental cell types suitable for further studies and co-culture models investigating TB and VCC interactions involved in early placental development.

Homeobox genes in the human placenta: Twists and turns on the path to find novel targets

Fetal growth restriction (FGR) is a clinically important human pregnancy disorder that is thought to originate early in pregnancy and while its aetiology is not well understood, the disorder is associated with placental insufficiency. Currently treatment for FGR is limited by increased surveillance using ultrasound monitoring and premature delivery, or corticosteroid medication in the third trimester to prolong pregnancy. There is a pressing need for novel strategies to detect and treat FGR at its early stage. Homeobox genes are well established as master regulators of early embryonic development and increasing evidence suggests they are also important in regulating early placental development. Most important is that specific homeobox genes are abnormally expressed in human FGR. This review focusses on identifying the molecular pathways controlled by homeobox genes in the normal and FGR-affected placenta. This information will begin to address the knowledge gap in the molecular aetiology of FGR and lay the foundation for identifying potential diagnostic and therapeutic targets.

Holistic preconception care: Providing real-time guidance via a mobile app to optimise maternal and child health.

Preconception is a critical period to optimise gamete function and early placental development, essential for successful conception and long-term maternal-child health. However, there is a lack of preconception services and consequently, global fertility rates continue to fall and mothers embark on their pregnancy journey in poor health. There is an urgent need to implement a holistic community-level preconception care programme to optimise risk factors for poor fecundability and improve long-term maternal-child health. We reviewed current evidence on fecundability lifestyle risk factors, the efficacy of existing preconception interventions and the use of digital platforms for health optimisation, to create a new digital-based preconception intervention model that will be implemented via an app. We present the theory, content and mode of delivery of this holistic model targeting couples planning for pregnancy. We propose a new model featuring a user-friendly mobile app, which enables couples to self-assess fecundability risks through a personalised risk score that drives a tailored management plan. This tiered management provides anticipatory guidance supported by evidence-based recommen-dations, and promotes ongoing engagement for behavioural optimisation and specialist referrals as required. Based on the health belief model, this new model delivered with a mobile app seeks to shift couples' perceptions about their susceptibility and severity of subfertility, benefits of making a change and barriers to change. Our proposed digital-based intervention model via a mobile app stands to enhance preconcep-tion care by providing personalised risk assessments, real-time feedback and tiered management to optimise preconception reproductive health of couples. This model forms a reference content framework for future preconception care intervention delivery.

The effects of leptin on human cytotrophoblast invasion are gestational age and dose-dependent

IntroductionLeptin and its receptors are expressed by the human placenta throughout gestation, yet the role of leptin in early human placental development is not well characterized. Leptin is overexpressed in the placentas from preeclamptic (PE) pregnancies. PE can result from the impaired invasion of fetal placental cells, cytotrophoblasts (CTBs), into the maternal decidua. We hypothesized that elevated leptin levels would impair human CTB invasion.MethodsThe effects of leptin on the invasion of human CTBs were evaluated in three cell models, HTR-8/SVneo cells, primary CTBs, and placental villous explants using invasion assays. Further, leptin receptor expression was characterized in all three cell models using RT-PCR. Further phosphokinase assays were performed in HTR-8/SVneo cells to determine signaling pathways involved in CTB invasion in response to differential leptin doses.ResultsWe found that, prior to 8 weeks gestation, leptin promoted CTB invasion in the explant model. After 11 weeks gestation in explants, primary CTBs and in HTR-8/SVneo cells, leptin promoted invasion at moderate but not at high concentrations. Further, leptin receptor characterization revealed that leptin receptor expression did not vary over gestation, however, STAT, PI3K and MAPK pathways showed different signaling in response to varied leptin doses.DiscussionThese data suggest that the excess placental leptin observed in PE may cause impaired CTB invasion as a second-trimester defect. Leptin’s differential effect on trophoblast invasion may explain the role of hyperleptinemia in preeclampsia pathogenesis.

TGFβ signalling: a nexus between inflammation, placental health and preeclampsia throughout pregnancy.

The placenta is a unique and pivotal organ in reproduction, controlling crucial growth and cell differentiation processes that ensure a successful pregnancy. Placental development is a tightly regulated and dynamic process, in which the transforming growth factor beta (TGFβ) superfamily plays a central role. This family of pleiotropic growth factors is heavily involved in regulating various aspects of reproductive biology, particularly in trophoblast differentiation during the first trimester of pregnancy. TGFβ signalling precisely regulates trophoblast invasion and the cell transition from cytotrophoblasts to extravillous trophoblasts, which is an epithelial-to-mesenchymal transition-like process. Later in pregnancy, TGFβ signalling ensures proper vascularization and angiogenesis in placental endothelial cells. Beyond its role in trophoblasts and endothelial cells, TGFβ signalling contributes to the polarization and function of placental and decidual macrophages by promoting maternal tolerance of the semi-allogeneic foetus. Disturbances in early placental development have been associated with several pregnancy complications, including preeclampsia (PE) which is one of the severe complications. Emerging evidence suggests that TGFβ is involved in the pathogenesis of PE, thereby offering a potential target for intervention in the human placenta. This comprehensive review aims to explore and elucidate the roles of the major members of the TGFβ superfamily, including TGFβs, bone morphogenetic proteins (BMPs), activins, inhibins, nodals, and growth differentiation factors (GDFs), in the context of placental development and function. The review focusses on their interactions within the major cell types of the placenta, namely trophoblasts, endothelial cells, and immune cells, in both normal pregnancies and pregnancies complicated by PE throughout pregnancy. A literature search was carried out using PubMed and Google Scholar, searching terms: 'TGF signalling preeclampsia', 'pregnancy TGF signalling', 'preeclampsia tgfβ', 'preeclampsia bmp', 'preeclampsia gdf', 'preeclampsia activin', 'endoglin preeclampsia', 'endoglin pregnancy', 'tgfβ signalling pregnancy', 'bmp signalling pregnancy', 'gdf signalling pregnancy', 'activin signalling pregnancy', 'Hofbauer cell tgfβ signalling', 'placental macrophages tgfβ', 'endothelial cells tgfβ', 'endothelium tgfβ signalling', 'trophoblast invasion tgfβ signalling', 'trophoblast invasion Smad', 'trophoblast invasion bmp', 'trophoblast invasion tgfβ', 'tgfβ preeclampsia', 'tgfβ placental development', 'TGFβ placental function', 'endothelial dysfunction preeclampsia tgfβ signalling', 'vascular remodelling placenta TGFβ', 'inflammation pregnancy tgfβ', 'immune response pregnancy tgfβ', 'immune tolerance pregnancy tgfβ', 'TGFβ pregnancy NK cells', 'bmp pregnancy NK cells', 'bmp pregnancy tregs', 'tgfβ pregnancy tregs', 'TGFβ placenta NK cells', 'TGFβ placenta tregs', 'NK cells preeclampsia', 'Tregs preeclampsia'. Only articles published in English until 2023 were used. A comprehensive understanding of TGFβ signalling and its role in regulating interconnected cell functions of the main placental cell types provides valuable insights into the processes essential for successful placental development and growth of the foetus during pregnancy. By orchestrating trophoblast invasion, vascularization, immune tolerance, and tissue remodelling, TGFβ ligands contribute to the proper functioning of a healthy maternal-foetal interface. However, dysregulation of TGFβ signalling has been implicated in the pathogenesis of PE, where the shallow trophoblast invasion, defective vascular remodelling, decreased uteroplacental perfusion, and endothelial cell and immune dysfunction observed in PE, are all affected by an altered TGFβ signalling. The dysregulation of TGFβ signalling in PE has important implications for research and clinical practice. Further investigation is required to understand the underlying mechanisms, including the role of different ligands and their regulation under pathophysiological conditions, in order to discover new therapeutic targets. Distinguishing between clinically manifested subtypes of PE and studying TGFβ signalling in different placental cell types holistically is an important first step. To put this knowledge into practice, pre-clinical animal models combined with new technologies are needed. This may also lead to improved human research models and identify potential therapeutic targets, ultimately improving outcomes for affected pregnancies and reducing the burden of PE.

Autophagy Inhibition in Trophoblasts Induces Aberrant Shift in CXCR4+ Decidual NK Cell Phenotype Leading to Pregnancy Loss

Background: Pregnancy, a complex biological phenomenon, relies on intricate maternal–fetal interactions for success. Decidual natural killer (dNK) cells and trophoblasts are pivotal in establishing immune tolerance at the maternal–fetal interface. The chemokine receptor CXCR4 plays a crucial role in NK cell development and immune tolerance during early placental development. Methods: Primary decidual immune cells from 42 women with normal pregnancies and 20 patients experiencing recurrent spontaneous abortions (RSAs) were studied. Gene transcription in NK cells was assessed using real-time polymerase chain reaction. In a co-culture system, we examined the influence of trophoblasts on CXCR4 expression in dNK cells, with subsequent analysis conducted via flow cytometry. The proportion of CXCR4+ NK cells was assessed using flow cytometry after co-culture with trophoblasts pre-treated with 3-MA or a p53 activator. Results: Our study confirmed a diminished presence of decidual CXCR4+ NK cells in RSA patients during early pregnancy. Co-culturing with a trophoblast-derived supernatant increased CXCR4 expression in dNK cells. In addition, trophoblast autophagy plays an educative role in regulating the dNK landscape via the IGF2-TP53-CXCR4 axis. Conclusion: Autophagy inhibition in trophoblasts induces an aberrant shift in the CXCR4+ dNK phenotype, potentially contributing to pregnancy loss. This sheds light on the nuanced behavior of dNK cells during pregnancy, offering promising therapeutic avenues to mitigate pregnancy complications.

Maternal CXCR4 deletion results in placental defects and pregnancy loss mediated by immune dysregulation.

CXCR4 is a key regulator of the development of NK cells and DCs, both of which play an important role in early placental development and immune tolerance at the maternal-fetal interface. However, the role of CXCR4 in pregnancy is not well understood. Our study demonstrates that adult-induced global genetic CXCR4 deletion, but not uterine-specific CXCR4 deletion, was associated with increased pregnancy resorptions and decreased litter size. CXCR4-deficient mice had decreased NK cells and increased granulocytes in the decidua, along with increased leukocyte numbers in peripheral blood. We found that CXCR4-deficient mice had abnormal decidual NK cell aggregates and NK cell infiltration into trophoblast areas beyond the giant cell layer. This was associated with low NK cell expression of granzyme B, a NK cell granule effector, indicative of NK cell dysfunction. Pregnancy failure in these mice was associated with abnormalities in placental vascular development and increased placental expression of inflammatory genes. Importantly, adoptive BM transfer of WT CXCR4+ BM cells into CXCR4-deficient mice rescued the reproductive deficits by normalizing NK cell function and mediating normal placental vascular development. Collectively, our study found an important role for maternal CXCR4 expression in immune cell function, placental development, and pregnancy maintenance.

THU633 Atonal BHLH Transcription Factor 8 (ATOH8) Functions In Decidualization

Abstract Disclosure: R. Thapa: None. B. Bany: None. ATOH8 is a member of the vast basic helix-loop-helix (bHLH) protein family that is widely known to play a role in various physiological and pathological processes. However, the functional significance of ATOH8 expression in the endometrium during implantation and in the first trimester of pregnancy in women is still lacking. In the mid to late secretory phase of the menstrual cycle, elongated fibroblast-like mesenchymal cells in the uterine endometrium begin to trans-differentiate into polygonal epithelioid-like (decidual) cells. During pregnancy, this process continues more broadly and supports successful embryo implantation and early placental development. We employed an established in vitro model using uterine fibroblast (HuF) cells derived from the decidua parietalis of term patients to investigate the function of ATOH8 during in vitro decidualization. All experiments were carried out using cells isolated from at least six independent patients (N=6). We measured the expression of classical decidualization marker genes and the characteristic shape change from small fibroblast-like cells to large epitheloid-like decidual cells to assess decidualization. Treating cells with steroids plus a membrane-permeable cAMP analog (EPC) for 48h caused in vitro decidualization of these cells, while treatment with vehicle alone had no effect. We discovered that ATOH8 expression was dramatically upregulated during this decidualization at both the mRNA and protein levels, with the protein primarily localized to the nucleus. The functional role of ATOH8 during decidualization was investigated using lentivirus-mediated shRNA knockdown or overexpression of ATOH8. When ATOH8 expression was silenced, we discovered that the ability of the cells to undergo decidualization was greatly and significantly diminished. On the other hand, overexpression of ATOH8 enhanced some aspects of decidualization. The addition of recombinant BMP2 alone had little effect on ATOH8 expression. However, in the presence of EPC it significantly enhanced ATOH8 expression. This effect of BMP2 on ATOH8 expression was inhibited by preincubating the cells with 500 nM DMH-1 (an ALK2/3 inhibitor) for one hr prior to inducing decidualization. Steroids alone did not affect ATOH8 or BMP2 expression. However, the addition of cAMP alone represented the major effect of EPC on ATOH8 expression while having a slight impact on BMP2 expression. A robust increase in BMP2 expression required the presence of both steroids and cAMP together. Our results indicate that ATOH8 plays a crucial role in human endometrial stromal cell decidualization. Further, our results suggest that ALK2/3 receptors are most likely involved in mediating the effect of BMP2 on increasing ATOH8 expression. Keywords: ATOH8, Decidualization, Embryo Implantation Presentation: Thursday, June 15, 2023

Dysregulation of Histone Deacetylases Inhibits Trophoblast Growth during Early Placental Development Partially through TFEB-Dependent Autophagy-Lysosomal Pathway.

Dysregulated biological behaviors of trophoblast cells can result in recurrent spontaneous abortion (RSA)-whose underlying etiology still remains insufficient. Autophagy, a conserved intracellular physiological process, is precisely monitored throughout whole pregnancy. Although the exact mechanism or role remains elusive, epigenetic modification has emerged as an important process. Herein, we found that a proportion of RSA patients exhibited higher levels of autophagy in villus tissues compared to controls, accompanied with impaired histone deacetylase (HDAC) expression. The purpose of this study is to explore the connection between HDACs and autophagy in the pathological course of RSA. Mechanistically, using human trophoblast cell models, treatment with HDAC inhibitor (HDACI)-trichostatin A (TSA) can induce autophagy by promoting nuclear translocation and transcriptional activity of the central autophagic regulator transcription factor EB (TFEB). Specifically, overactivated autophagy is involved in the TSA-driven growth inhibition of trophoblast, which can be partially reversed by the autophagy inhibitor chloroquine (CQ) or RNA interference of TFEB. In summary, our results reveal that abnormal acetylation and autophagy levels during early gestation may be associated with RSA and suggest the potential novel molecular target TFEB for RSA treatment.

Development of a human iPSC-derived placental barrier-on-chip model

Although recently developed placenta-on-chip systems opened promising perspectives for placental barrier modeling, they still lack physiologically relevant trophoblasts and are poorly amenable to high-throughput studies. We aimed to implement human-induced pluripotent stem cells (hiPSC)-derived trophoblasts into a multi-well microfluidic device to develop a physiologically relevant and scalable placental barrier model. When cultured in a perfused micro-channel against a collagen-based matrix, hiPSC-derived trophoblasts self-arranged into a 3D structure showing invasive behavior, fusogenic and endocrine activities, structural integrity, and expressing placental transporters. RNA-seq analysis revealed that the microfluidic 3D environment boosted expression of genes related to early placental structural development, mainly involved in mechanosensing and cell surface receptor signaling. These results demonstrated the feasibility of generating a differentiated primitive syncytium from hiPSC in a microfluidic platform. Besides expanding hiPSC-derived trophoblast scope of applications, this study constitutes an important resource to improve placental barrier models and boost research and therapeutics evaluation in pregnancy.

P-224 Basonuclin 1 prevents intrauterine growth restriction via inhibiting necroptosis

Abstract Study question Is basonuclin 1 (BNC1) involved in intrauterine growth restriction (IUGR), and what’s the underlying mechanism? Summary answer BNC1 is significantly decreased in the placenta of IUGR patients. BNC1 deficiency engenders IUGR in Bnc1 truncation mutation (Bnc1tr/tr) mice model by inducing placental necroptosis. What is known already IUGR is among the leading causes of perinatal morbidity and mortality. IUGR occurs due to multiple factors, including genetic, placental, fetal, and maternal factors. Among which genetic factors remain largely unknown. Our previous exploration found that Bnc1 mutationmice exhibit low birth weight and survival rates, indicating BNC1 may play a potential role in fetal and placental development. Necroptosis is a recently recognized cell death pathway that may contribute to placental pathophysiology in IUGR patients. While the underlying mechanism remains largely unknown. Study design, size, duration A clinical retrospective cohort study of 40 IUGR patients (diagnosed by Hadlock ultrasound measurements) and 40 controls were included (2017–2022) for placenta collection. Bnc1 targeted mutation mouse was on a C57BL/6 J background. Male and female mice of the Bnc1+/tr genotype were mated to produce Bnc1+/+, Bnc1+/tr, and Bnc1tr/tr mice. Placenta and fetuses were obtained on the 15th and 18th days of pregnancy. Participants/materials, setting, methods The following analyses were performed: (i) Immunohistochemistry for detecting the location and expression of BNC1 in the placenta of humans and mice, (ii) placental and fetal weights for evaluation of IUGR development, (iii) morphometric evaluation of fetal utilizing Alcian blue and alizarin red staining, (iv) morphometric evaluation of placental compartments utilizing H&E staining, TUNEL staining, and TEM analysis, (v) RNA sequencing (RNA-seq) of placental tissues. Main results and the role of chance BNC1 was specifically highly expressed in trophoblasts and endothelial cells in the early and mature placental development stages of humans and mice. The expression of BNC1 was significantly decreased in the placenta of IUGR patients compared to the control group (P < 0.0001). In the mice model, the number of Bnc1tr/tr fetuses was significantly decreased compared with wild-type Bnc1+/+ fetuses on the 18th day of pregnancy. While the number of Bnc1tr/tr fetuses and Bnc1+/+ fetuses was similar on the 15th day of pregnancy, indicating the loss of Bnc1tr/tr fetuses between the two stages. Besides, both the Bnc1tr/tr fetal and placental weights were significantly decreased on the 15th day of pregnancy compared with Bnc1+/+ fetuses and placenta (P < 0.01). The Bnc1 truncation mutation caused poor development of the placental labyrinthine layer with an increased number of TUNEL-positive foci. Transmission electron microscopy also revealed a disorganized labyrinthine layer with defects in cytoplasm translucence, loss of plasma membrane integrity, swollen mitochondria, and decondensed chromatin. Finally, RNA sequencing of placental tissues indicated BNC1 deficiency-induced IUGR may be modulated by necroptosis. In conclusion, we found a relationship between the disturbed BNC1 expression and the occurrence of IUGR through necroptosis. Limitations, reasons for caution This study used only Bnc1 truncation mutation mice model, the other animal model with placenta-conditional knockout mice was needed to consolidate the results. Besides, further mechanism exploration should be conducted in both human and mouse cell lines. Wider implications of the findings Our work suggests a new gene related to the development of IUGR, which provides early diagnosis and treatment for managing IUGR, thus improving outcomes for both fetal and gravida. Trial registration number not applicable

Glucose, Insulin and Oxygen Modulate Expression of Serotonin-Regulating Genes in Human First-Trimester Trophoblast Cell Line ACH-3P.

Serotonin signaling plays an important role in regulating development and functions of the placenta. We hypothesized that metabolic disturbances associated with maternal obesity and/or gestational diabetes mellitus (GDM) affect placental serotonin homeostasis. Therefore, we examined the effects of high glucose (25 mM) and insulin (10 nM)-two hallmarks of maternal obesity and GDM-on mRNA expression of key regulators of serotonin homeostasis, including serotonin transporter (SERT), tryptophan hydroxylase 1 (TPH1), and monoamine oxidase A (MAOA), in the first-trimester trophoblast cell line ACH-3P, focusing on oxygen levels characteristic of early human placental development. Glucose downregulated expression of SERT and MAOA independently of oxygen level and upregulated expression of TPH1 at 6.5% oxygen but not at 2.5% oxygen. Compared to 6.5% oxygen, 2.5% oxygen upregulated SERT and downregulated TPH1 expression, with no effect on MAOA expression. Insulin upregulated SERT only at 2.5% oxygen but had no effect on TPH1 and MAOA expression. These results suggest that maternal metabolic alterations in early pregnancy may be a driving force for changes in placental serotonin homeostasis.

Animal models of the placenta accreta spectrum: current status and further perspectives.

Placenta accreta spectrum disorder (PAS) is a kind of disease of placentation defined as abnormal trophoblast invasion of part or all of the placenta into the myometrium, even penetrating the uterus. Decidual deficiency, abnormal vascular remodeling in the maternal-fetal interface, and excessive invasion by extravillous trophoblast (EVT) cells contribute to its onset. However, the mechanisms and signaling pathways underlying such phenotypes are not fully understood, partly due to the lack of suitable experimental animal models. Appropriate animal models will facilitate the comprehensive and systematic elucidation of the pathogenesis of PAS. Due to the remarkably similar functional placental villous units and hemochorial placentation to humans, the current animal models of PAS are based on mice. There are various mouse models induced by uterine surgery to simulate different phenotypes of PAS, such as excessive invasion of EVT or immune disturbance at the maternal-fetal interface, which could define the pathological mechanism of PAS from the perspective of the "soil." Additionally, genetically modified mouse models could be used to study PAS, which is helpful to exploring the pathogenesis of PAS from the perspectives of both "soil" and "seed," respectively. This review details early placental development in mice, with a focus on the approaches of PAS modeling. Additionally, the strengths, limitations and the applicability of each strategy and further perspectives are summarized to provide the theoretical foundation for researchers to select appropriate animal models for various research purposes. This will help better determine the pathogenesis of PAS and even promote possible therapy.

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

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