Mechanisms of early placental development in mouse and humans

Safety of nanoparticle therapies during pregnancy: A systematic review and meta-analysis

The exclusion of pregnant women from clinical trials has led to insufficient safety data for many treatments, making it necessary to evaluate their potential benefits and risks during preclinical stages. Nanomedicines show potential for reduced toxicity but there is limited evidence about their safety for pregnant women and their fetuses. We conducted the first systematic review and meta-analysis of the effect of nanoparticles (NPs) on a key outcome of fetal toxicity (low birth weight) in murine models. In the meta-analysis of mouse models, negatively charged NPs tended to decrease birth weight (-69.8 mg, 95 % CI: -196 to 56.5), as did small (-191 mg, 95 % CI: -369 to -13.3) and plain inorganic nanosystems (-249 mg, 95 % CI: -535 to 37.4). In contrast, positively charged NPs resulted in increased birth weight (+29.3 mg, 95 % CI: 23.4 to 35.2). All findings were validated in studies with low heterogeneity and low risk of publication bias. Neither large NPs (+4.37 mg; 95 % CI: -45.3 to 54.0) nor polymer-coated NPs (+16.5 mg; 95 % CI: -44.7 to 77.6) had any clear association with birth weight. Similar results were observed in other models and experimental designs from articles not included in the meta-analysis, although no conclusions were drawn for other parameters due to high variability. Our findings pave the way for future research and the rational development of safer nanomedicines for use during pregnancy.

Epigenome-wide association study of pregnancy exposure to green space and placental DNA methylation

Green space exposure during pregnancy has been associated with lower risk of adverse birth outcomes, but the biological mechanisms remain unclear. Epigenetic changes, such as DNA methylation (DNAm), may contribute to this association. The placenta, crucial for foetal development, has been understudied in relation to prenatal green space exposure and DNAm on a genome-wide scale. Here, we aimed to investigate the association between green space exposure during pregnancy and epigenome-wide placental DNAm in 550 mother-child pairs from the Barcelona Life Study Cohort (BiSC) in Spain. Green space exposure was assessed as (i) residential surrounding greenness (satellite-based Normalized Difference Vegetation Index (NDVI) in buffers of 100 m, 300 m and 500 m), (ii) residential distance to the nearest major green space (meters), (iii) use of green space (hours/week), and (iv) visual access to greenery through the home window (≥half of the view). Placental DNAm was measured with the EPIC array. Differentially methylated positions (DMPs) were identified using robust linear regression models adjusted for covariates, while differentially methylated regions (DMRs) were identified using the dmrff method. After Bonferroni correction, cg14852540, annotated to SLC25A10 gene, showed an inverse association with residential greenness within 500 m buffer. Additionally, 101 DMPs were suggestively significant (p-values <1 × 10-5) and annotated to genes involved in glucocorticoid-related pathways, inflammatory response, oxidative stress response, and oocyte maturation. No DMRs were identified. Overall, we identified an association between residential greenness and DNAm levels at one CpG in the SLC25A10 gene. Larger studies are needed to validate these findings and understand the biological pathways.

Ex vivo functional whole organ in biomedical research: a review

Model systems are critical in biomedical and preclinical research. Animal and in vitro models serve an important role in our current understanding of human physiology, disease pathophysiology, and therapy development. However, if the system is between cell culture and animal models, it may be able to overcome the knowledge gap that exists in the current system. Studies employing ex vivo organs as models have not been thoroughly investigated. Though the integration of other organs and systems has an impact on many biological mechanisms and disorders, it can add a new dimension to modeling and aid in the identification of new possible therapeutic targets. Here, we have discussed why the ex vivo organ model is desirable and the importance of the inclusion of organs from diverse species, described its historical aspects, studied organs as models in scientific research, and its ex vivo stability. We also discussed, how an ex vivo organ model might help researchers better understand organ physiology, as well as organ-specific diseases and therapeutic targets. We emphasized how this ex vivo organ dynamics will be more competent than existing models, as well as what tissues or organs would have potentially viable longevity for ex vivo modeling including human tissues, organs, and/or at least biopsies and its possible advantage in clinical medicine including organ transplantation procedure and precision medicine.

Comparative analysis of the syncytiotrophoblast in placenta tissue and trophoblast organoids using snRNA sequencing

The syncytiotrophoblast (STB) is a multinucleated cell layer that forms the outer surface of human chorionic villi. Its unusual structure, with billions of nuclei in a single cell, makes it difficult to resolve using conventional single-cell methods. To better understand STB differentiation, we performed single-nucleus and single-cell RNA sequencing on placental tissue and trophoblast organoids (TOs). Single-nucleus RNA-seq was essential for capturing STB populations, revealing three nuclear subtypes: a juvenile subtype co-expressing CTB and STB markers, one enriched in oxygen sensing genes, and another in transport and GTPase signaling. Organoids grown in suspension culture (STBout) showed higher expression of STB markers, hormones, and a greater proportion of the transport-associated nuclear subtype while TOs grown with an inverted polarity (STBin) exhibited a higher proportion of the oxygen sensing nuclear subtype. Gene regulatory analysis identified conserved STB markers, including the chromatin remodeler RYBP. Although RYBP knockout did not impair fusion, it downregulated CSH1 and upregulated oxygen-sensing genes. Comparing STB expression in first trimester, term, and TOs revealed shared features but context-dependent variability. These findings establish TOs as a robust platform to model STB differentiation and nuclear heterogeneity, providing insight into the regulatory networks that shape placental development and function.

An Exploration into the Safe and Precise In Vivo Fluorescence Visualization of Uteroplacental Circulation in the NIR-II Window

The uteroplacental circulation is essential for maintaining normal placental physiology and ensuring fetal development. Imaging this circulation is crucial for a comprehensive understanding of its physiological characteristics and associated pathological processes. Fluorescence imaging in the second near-infrared window (NIR-II, 900-1880 nm) offers significant advantages, including high resolution and deep tissue penetration, facilitating more accurate in vivo assessments. In this study, we employed nanoparticles composed of organic fluorescent dyes with NIR-II emission for precise imaging of the uteroplacental circulation. This approach enabled visualization of the uterine artery and placental blood perfusion in pregnant mice with high resolution. We successfully examined the developmental status across different pregnancy stages and assessed pathological alterations associated with inflammation-induced injury. Furthermore, the maternal and fetal safety of the nanoparticles was validated through comprehensive evaluations. These investigations present a novel approach for studying the formation and development of uteroplacental circulation, as well as related pathological conditions.

Tea polyphenols and EGCG induce preeclampsia-like symptoms by reducing 2-methoxyestradiol

Preeclampsia (PE), a severe pregnancy-specific disorder, poses significant health risks to both mothers and fetuses. Certain dietary habits, such as tea consumption, may affect the activity of enzymes involved in hormone metabolism, leading to alterations in the levels of important pregnancy-related hormone metabolites, such as 2-methoxyestradiol (2-MeO-E2), which may contribute to the development of PE. To investigate the effect of tea intake on pregnancy, we conducted both in vivo and in vitro experiments. Pregnant rats were administered tea polyphenols and epigallocatechin gallate (EGCG) by gavage starting from pregnancy day 10. We found that tea polyphenols and EGCG intake during pregnancy induced PE-like symptoms in the rats such as hypertension, proteinuria and growth restriction of fetuses. These symptoms could be rescued by cotreatment of 2-MeO-E2. Notably, the levels of the estrogen metabolite 2-MeO-E2 in rat blood were significantly reduced, and the activity of the enzyme responsible for its metabolism, catechol-O-methyltransferase (COMT), was also inhibited. Furthermore, EGCG impaired the migration ability of HTR8/SVneo cells, which could be alleviated by 2-MeO-E2 supplementation. These findings indicate that tea polyphenols intake during pregnancy can cause PE-like symptoms by inhibiting COMT activity and production of 2-MeO-E2.

AHR activated placental adrenomedullin: A plausible factor in smoke-induced preeclampsia protection

INTRODUCTION

The placenta develops as trophectoderm cells invade and secrete peptides to remodel the maternal vasculature. Impaired invasion can lead to preeclampsia. Maternal smoking during pregnancy can cause miscarriage and fetal developmental problems. Yet curiously, cigarette use during pregnancy correlates with a decreased risk for preeclampsia. To explore this, we have studied the secreted peptide, adrenomedullin (ADM) that promotes placentation and is increased by maternal smoking. The aryl hydrocarbon receptor (AHR) is a transcription factor that binds cigarette-associated carcinogenic ligands. We hypothesized that AHR activation by cigarette smoke induces Adm to promote placental development.

METHODS

Pregnant transgenic animals exhibiting overexpression of Adm or genetic loss of Ahr were exposed to cigarette smoke. Embryo and placenta tissues were evaluated. Immortalized trophoblast cells (HTR8/SVneo) were also exposed to cigarette smoke extract before AHR chromatin immunoprecipitation with quantitative polymerase chain reaction.

RESULTS

Ablation of Ahr reduced embryo weights and embryo/placental weight ratios. Further, overexpression of Adm increased placental weights in sham treated conditions yet caused abnormal placental growth and stunted embryo development with cigarette smoke. Finally, chromatin immunoprecipitation results demonstrated that AHR significantly binds to two sites on the ADM promoter.

DISCUSSION

In a mouse model of high Adm expression, cigarette smoke can elicit stunted embryo and placental weights and abnormal placental morphology. Thus, tightly regulated ADM levels are critical for murine gestational development and in the presence of cigarette smoke, are promoted by AHR-mediated transcriptional activation. These studies provide compelling results suggesting AHR drives ADM upregulation in the smoke-exposed placenta.

Chronic replication stress-mediated genomic instability disrupts placenta development in mice

Abnormal placentation drives many pregnancy-related pathologies and poor fetal outcomes, but the underlying molecular causes are understudied. Here, we show that persistent replication stress due to mutations in the MCM2-7 replicative helicase disrupts placentation and reduces embryo viability in mice. MCM-deficient embryos exhibited normal morphology but their placentae had a drastically diminished junctional zone (JZ). Whereas cell proliferation in the labyrinth zone (LZ) remained unaffected, JZ cell proliferation was reduced during development. MCM2-7 deficient trophoblast stem cells (TSCs) failed to maintain stemness, suggesting that replication stress affects the initial trophoblast progenitor pool in a manner that preferentially impacts the developing JZ. In contrast, pluripotency of mouse embryonic stem cells with MCM2-7 deficiency were not affected. Developing female mice deficient for FANCM, a protein involved in replication-associated DNA repair, also had placentae with a diminished JZ. These findings indicate that replication stress-induced genomic instability compromises embryo outcomes by impairing placentation.

Gestational Exposure to Black Phosphorus Nanoparticles Induces Placental Trophoblast Dysfunction by Triggering Reactive Oxygen Species-Regulated Mitophagy

As a type of two-dimensional nanomaterial, black phosphorus (BP) has attracted considerable interest for applications in various fields. Despite its advantages, including biodegradability and biocompatibility, recent studies have shown that BP exhibits cytotoxicity in different types of cells. However, no studies have investigated the effects of BP exposure during pregnancy. Herein, we first investigated the effect of gestational exposure to BP nanoparticles (BPNPs) in a mouse model. Our findings indicated that BPNPs exposure restricted fetal growth and hindered placental development. In HTR8/SVneo trophoblast cells, BPNPs inhibited cell proliferation, migration, and invasion and caused apoptosis in a dose-dependent manner. Furthermore, BPNPs induced intracellular reactive oxygen species (ROS) overproduction and extensive mitochondrial damage. We further demonstrated that BPNPs promoted mitophagy via the PINK1/Parkin signaling pathway. Parkin siRNA knockdown rescued BPNPs-induced trophoblast dysfunction, while ROS inhibition attenuated BPNPs-induced cytotoxicity by reducing mitochondrial damage. Finally, treatment with mdivi-1, a mitophagy inhibitor, mitigated mitochondrial membrane potential reduction, excessive mtROS production, and the resulting trophoblast dysfunction. In vivo model investigation indicated that the application of mdivi-1 ameliorated embryonic resorption and fetal growth by alleviating placental damage. In summary, gestational exposure to BPNPs impairs fetal growth by inducing placental trophoblast dysfunction through ROS-regulated, PINK1/Parkin-dependent mitophagy.

Single-cell RNA sequencing reveals altered placental microenvironment due to maternal high-fat diet

BACKGROUND

The prevalence of childhood metabolic diseases has markedly increased in recent decades whereas the effects of maternal nutrients affecting the placental microenvironment are not clearly addressed.

METHODS

In the present study, female C57BL/6J mice were fed with a high-fat diet (HFD) or control diet (CON) for 5 weeks prior to mating and then during pregnancy. Single-cell RNA sequencing (scRNA-seq) was used to dissect the placental cell atlas at embryonic day(E) 18.5.

RESULTS

Maternal HFD led to a reduction in the composition of placental labyrinth zone (LZ) trophoblast cells and endothelial cells, together with a diminished LZ area and narrowed fetal vessels, related to a decreased placental efficiency. Pro-inflammatory placental NK1 cells and M1-like macrophages were more apparent in the placenta from HFD dams with inflammation features. Increased glycogen deposition and glycogen trophoblast cells were also detectable in the HFD placenta, likely associated with the altered metabolism of placental NK cells and macrophages.

CONCLUSIONS

Maternal HFD before and during pregnancy leads to an altered placental microenvironment with more inflammatory features and abnormal metabolic properties, which provides a better understanding on the mechanisms of intergenerational inheritance.

Upregulation of OTULIN Alleviated Recurrent Pregnancy Loss by Suppressing Trophoblast Dysfunction and NF-κB Signaling Pathway

Recurrent pregnancy loss (RPL) is one of obstetrical diseases with no effective therapy methods. Trophoblast cell dysfunction and inflammation induce embryo implantation insufficiency, thereby resulting in RPL. OTU deubiquitinase with linear linkage specificity (OTULIN) plays a role in regulating the immune response and cell death. However, the role of OTULIN in RPL remains unclear. Spontaneous abortion mouse model and lipopolysaccharide-treated HTR-8/SVneo cells were used to investigate the role of OTULIN in RPL. OTULIN expression was downregulated in the labyrinth trophoblast of RPL mice and LPS-treated trophoblast cells. The embryonic reabsorption rate was decreased in OTULIN-overexpressed spontaneous abortion mice, accompanied with the increase in placental/fetus weight ratio. OTULIN overexpression significantly inhibited apoptosis in vivo and in vitro, as evidenced by the decrease in the activity of caspase 3. The expression of pro-inflammatory cytokines was decreased with OTULIN overexpression. Moreover, OTULIN overexpression decreased p-IκBα/IκBα and p-p65/p65 ratio. The nuclear translocation of NF-κB was suppressed via OTULIN overexpression both in vivo and in vitro. Our study suggested that OTULIN deficiency might cause inflammation and trophoblast abnormalities in RPL. The supplementation with OTULIN might alleviate the development of RPL via inhibiting NF-κB mediated inflammation response.

m6A deficiency impairs uterine spiral artery remodeling to induce preeclampsia-like symptoms via FGF2

Failures in uterine spiral artery remodeling can lead to placental defects and subsequent preeclampsia, a leading cause of fetal and maternal mortality during pregnancy. N6-methyladenosine (m6A), the most abundant mRNA modification, is dysregulated in samples with preeclampsia. However, whether and how m6A regulates uterine spiral artery remodeling and leads to subsequent preeclampsia in vivo remains unexplored. In this study, we generated two m6A deficiency mouse models: one with a trophoblast-specific knockout of the m6A methyltransferase gene Mettl3, and another with a methyltransferase enzyme mutation. Using these models, we demonstrated that m6A deficiency impaired extravillous trophoblasts (EVTs) infiltration into the uterine spiral arteries, and the remodeling of the spiral arteries in vivo. We further showed that m6A inhibition induced preeclampsia-like symptoms. Mechanistically, we revealed that the m6A modification of FGF2 mRNA, which encodes a secreted peptide implicated in preeclampsia, facilitated its expression. Notably, administration of the FGF2 peptide largely restored EVTs invasion and uterine spiral artery remodeling in m6A-deficient mice. Our findings underscore the importance of m6A in facilitating uterine spiral artery remodeling and prove the pathological mechanisms in vivo, suggesting a new therapeutic approach for preeclampsia caused by m6A deficiency.

Subchronic Exposure to Polystyrene Nanoplastics Disrupts Placental Development and Calcium Homeostasis: Insights from In Vivo and In Vitro Models

Nanoplastics have recently emerged as persistent pollutants of global concern that pose substantial risks to human health. However, the long-term adverse effects of nanoplastics on the female reproductive system remain unclear. Polystyrene nanoplastics (PS-NPs; 50 nm diameter) were selected as representative nanosized plastic particles to investigate the potential effects of subchronic prenatal and gestational exposure via drinking water on placental development in ICR (CD-1) mice. Maternal exposure to 10 mg/L PS-NPs induced an increase in fetal resorption rate and significantly increased fetal weight. Further observation of the placental morphology showed that PS-NPs exposure led to an aberrant placental structure and damaged the trophoblast cells. At the cellular level, PS-NPs exposure promoted the proliferation, migration, and invasion of HTR-8/SVneo cells. Mechanistically, transcriptomic and proteomic analyses revealed that PS-NPs triggered placental calcium disturbances and upregulated the Stam2 expression in mice. STAM2 induced by PS-NPs mediates the disruption of trophoblastic calcium homeostasis and regulates cell functions by disturbing the lysosomal degradation of the calcium channel protein IP3R3 and promoting intracellular calcium inflow by increasing the level of TRPV6 in HTR-8/SVneo cells. Therefore, our results indicated that trophoblastic calcium dyshomeostasis is the main mechanism by which subchronic PS-NPs exposure induces abnormal placental development. These findings reveal a link between subchronic PS-NPs exposure and placental damage and elucidate the underlying molecular mechanism, providing evidence for environmental triggers of adverse pregnancy and highlighting the risk of plastic products to pregnant women.

Analogue-Specific Transplacental Transfer of Organophosphate Flame Retardants in ICR Mouse Mediated by Active Transport

Prenatal exposure to organophosphate flame retardants (OPFRs) may pose potential health risks to offspring. While prior studies have demonstrated that OPFRs can be transferred from mothers to fetuses, the mechanism underlying transplacental transfer remains unclear. The pregnant ICR mouse and JAR cell (a monolayer model), in combination with molecular docking, were used to explore the underlying mechanism. OPFRs were rapidly metabolized into diester metabolites following oral gavage in the ICR mouse, with considerable concentrations detected in maternal serum, amniotic fluid, and placenta, as well as fetus within 3 h. After 6 h, the accumulation ratios of OPFRs between the mother and fetus exhibited a parabolic relationship with log KOW. Oral exposure resulted in a decrease in interstitial cells in the decidua and an expansion of vascular systems in the labyrinthine area. RT-qPCR analysis revealed upregulated expression levels of transporter mRNA in the placenta, suggesting a protective mechanism characterized by greater efflux than influx transport efficiency. Metabolic inhibitors applied during in vitro transepithelial transport experiments using the JAR cells significantly reduced the transport efficiency, indicating that active transport facilitated the transplacental transport of aryl-OPFRs, with reductions exceeding 50%. Molecular docking analysis indicated that aryl-OPFRs exhibited greater binding affinities to placental transporters compared to other types of OPFRs, with more bonding interactions. These findings offer new insights into the potential health impacts of OPFR exposure and highlight the importance of elucidating their transplacental transport mechanisms.

The Chromosome 19 miRNA Cluster Guards Trophoblasts Against Overacting Innate Immunity

To maintain pregnancy health, the human placenta delicately balances protection of the developing fetus from invading pathogens with suppression of excessive inflammation that could lead to fetal and neonatal autoimmune disorders. Previous research, including our own, has shown that small RNA products of the Chromosome 19 MicroRNA Cluster (C19MC) promote viral resistance in non-trophoblastic cells. However, the role of C19MC products in placental trophoblasts remained unclear. Here, we analyzed chromatin accessibility in the C19MC enhancer and identified a previously unknown regulatory domain. Deletion of this domain silenced the expression of C19MC microRNA and Alu elements in trophoblasts. This silencing unexpectedly led to marked activation of cellular innate immune response and strikingly increased Toll-like receptor 3 (TLR3)-mediated sensitivity to poly(I:C), a viral RNA mimic. Our data suggest that C19MC non-coding RNAs interfere with endosomal TLR3 activation in trophoblasts, highlighting a previously unrecognized mechanism for hindrance of excessive innate immune activation.

Transcription Factor FOXD3 Regulates ELAV1/TLR4 Axis in Antiphospholipid Syndrome to Mediate Proliferation and Migration of Trophoblasts

This study focused on exploring the mechanism of transcription factor FOXD3 promoting the proliferation, migration, and invasion of trophoblast through ELAV1/TLR4 axis. The placenta villi from pregnancy patients with antiphospholipid syndrome (APS) and pregnancy controls were collected, along with the HTR-8/SVneo cell lines were obtained to detect the FOXD3, ELAV1, and TLR4 expressions using qRT-PCR and western blot. The interaction of ELAV1 with TLR4 mRNA was verified using RNA immunoprecipitation. The binding of FOXD3 with ELAV1 was detected using Chromatin Immunoprecipitation and dual luciferase reporter gene assay. After cell transfection, the cell proliferation, cell cycle distribution, invasion, and migration of the HTR-8/SVneo cell line were also measured. FOXD3, ELAV1, and TLR4 were elevated in the placenta villi of APS patients. TLR4 knockdown can promote the proliferation, invasion, and migration ability of HTR-8/SVneo cells. ELAV1 can bind TLR4 mRNA and increase its stability. TLR4 overexpression can inhibit the promotive effect of ELAV1 knockdown on HTR-8/SVneo cell biological functions. FOXD3 can bind the ELAV1 promoter and increase its transcription level to mediate HTR-8/SVneo cell biological functions. FOXD3 can bind and increase ELAV1 expression to stabilize TLR4 mRNA level, thereby increasing TLR4 expression and inhibiting the proliferation, invasion, and migration ability of trophoblast.

The impact of oral cannabis consumption during pregnancy on maternal spiral artery remodelling, fetal growth and offspring behaviour in mice

BACKGROUND

The use of cannabis during pregnancy is rising following its widespread legalization. Cannabidiol (CBD) is gaining popularity due to the public perception that it is safer than the psychoactive cannabis component Δ9-tetrahydrocannabinol (THC). However, while evidence underpins the harm of THC and cannabis smoke on fetal development, there is minimal research on the safety of CBD and oral cannabis. The current study aims to decipher the safety of oral CBD and THC use during pregnancy.

METHODS

Using a mouse model, we directly compared the effects of oral CBD and THC oil exposure (20 mg/kg body weight) from early to mid-gestation on implantation site remodelling and fetal growth. We examined offspring behaviour and metabolic activity using both traditional and automated cage systems. Lastly, using human and mouse immune cells we assessed how CBD and THC influence angiogenic factor production.

FINDINGS

We observed impaired maternal spiral artery remodelling in cannabis exposed mice and found that CBD and THC disrupt immune cell angiogenic factor production. Oral consumption of THC or CBD oil also resulted in significant fetal growth impairment and led to long-lasting sex-dependent consequences as male offspring exhibited altered aggression and metabolic activity while females had impaired spatial learning.

INTERPRETATION

Our results show that oral consumption of either CBD or THC oil during pregnancy in mice results in harm to the developing fetus and causes behavioural changes after birth.

FUNDING

The Michael G. DeGroote Centre for Medicinal Cancer Research, the Canadian Institutes of Health Research, and the Canadian Foundation for Innovation.

Origin, fate and function of extraembryonic tissues during mammalian development

Extraembryonic tissues have pivotal roles in morphogenesis and patterning of the early mammalian embryo. Developmental programmes mediated through signalling pathways and gene regulatory networks determine the sequence in which fate determination and lineage commitment of extraembryonic tissues take place, and epigenetic processes allow the memory of cell identity and state to be sustained throughout and beyond embryo development, even extending across generations. In this Review, we discuss the molecular and cellular mechanisms necessary for the different extraembryonic tissues to develop and function, from their initial specification up until the end of gastrulation, when the body plan of the embryo and the anatomical organization of its supporting extraembryonic structures are established. We examine the interaction between extraembryonic and embryonic tissues during early patterning and morphogenesis, and outline how epigenetic memory supports extraembryonic tissue development.

Uncovering the Fluctuation of Peroxynitrite during Early Embryonic Development Using an Integrative Nanobeacon

Embryonic development is the beginning of life, and various kinds of bioactive molecules are implicated in this crucial process. Especially in its early stage, some important biochemical reactions regulating physiological balance may be resuscitated. Thus, revealing the dynamic changes of bioactive molecules during early embryonic development is crucial to the elucidation of biological phenomena. Peroxynitrite (ONOO-) is a typical signaling molecule in intercellular communication. However, up to now, no work has studied the fluctuation of ONOO- during early embryonic development due to its low content, especially in mammals. Herein, a polymeric nanobeacon that integrates an ONOO--responsive degradable scaffold and a fluorescence amplification module, named IFN, was designed to selectively sense embryonic ONOO- with high sensitivity. By virtue of the specific dye, ONOO- was sensitively detected in the range of 0-4.5 μM with a detection limit of 20.4 nM. From the attractive embryonic results, a sudden increase in ONOO- content after fertilization was observed in a mammalian model, while the level of ONOO- decreased slightly at the four-cell and eight-cell stages, finally reaching an equilibrium throughout the morula and blastocyst stages. This phenomenon is due to the resuscitation of ovotids, the activation of some life events by fertilization, and the subsequent establishment of physiological balance. This work not only suggests that ONOO- plays a positive role in normal embryonic development but also highlights the molecular events occurring at the initial phase of life. Furthermore it opens up new avenues for monitoring chemical changes during mammalian embryonic development.

Impacts of Gestational F-53B Exposure on Fetal Neurodevelopment: Insights from Placental and Thyroid Hormone Disruption

It has been evidenced that chlorinated polyfluoroalkyl ether sulfonic acids (Cl-PFESAs) have strong potential cross the placental barrier, but their adverse effects on offspring remain unclear. In this study, pregnant mice received daily intraperitoneal injections of chlorinated polyfluorinated ether sulfonate (Cl-PFESA; commercially known as F-53B, primarily comprising 6:2 Cl-PFESA and 8:2 Cl-PFESA) at dosages of 40 and 200 μg/kg from gestational days 6 to 17. Following gestational exposure, distinct accumulation of 6:2 and 8:2 Cl-PFESAs was observed in both the placenta and fetal brain, confirming their penetration across the placental and fetal blood-brain barriers. Maternal exposure to F-53B disrupted the placental 11β-hydroxysteroid dehydrogenase type 2 (hsd11b2) barrier, characterized by hypermethylation of its promoter, decreased blood sinusoids in labyrinth layer, and downregulation of the nutrient transport genes, thereby severely impairing the placenta's protective and nutrient transfer functions. Concomitantly, significant fetal intrauterine growth restriction indicated by decreased fetal weight and crown-rump length was observed. Additionally, changes in thyroid hormones, along with transcriptional and DNA methylation alterations in the promoter regions of transthyretin (ttr) and deiodinase 3 (dio3) genes, were noted in the placenta. These epigenetic changes might affect the maternal-fetal transport of thyroid hormones, possibly leading to disrupted thyroid function in the F1 generation. With the decreased nutrient transport capacity of the placenta, T4 levels in the fetus are significantly reduced, resulting in significant fetal neurodevelopmental abnormalities, reduced nerve cell proliferation (Ki67), and damage to synaptic plasticity. This study reveals unveil the hidden dangers of F-53B, highlighting its neurotoxic effects on fetal development through the disruption of thyroid hormone transport across the placenta.

The landscape of decidual immune cells at the maternal-fetal interface in parturition and preterm birth

BACKGROUND

Parturition is similar to an inflammatory response in which resident and infiltrating immune cells release cytokines and chemokines into the maternal-fetal interface, promoting expulsion of the fetus from the mother. The untimely activation of these inflammatory pathways can result in preterm labor. The maternal-fetal interface is composed mainly of decidual tissue and placental villous space.

OBJECTIVE

The objective of this review is to examine the role and mechanisms of decidual immune cells during parturition and preterm birth. A deeper understanding of decidual immune cells at the maternal-fetal interface could provide significant insight into parturition and preterm birth pathogenesis.

METHODS

We searched major databases (including PubMed, Web of Science, and Google Scholar etc.) for literature encompassing decidual immune cells, parturition and preterm birth up to July 2024 and combined with studies found in the reference lists of the included studies.

RESULTS

Decidual neutrophils release inflammatory mediators that facilitate parturition. The M1/M2 ratio of decidual macrophages increases among preterm birth population. Mast cells may cause uterine contractions. In parturition and preterm birth, there is an increase in CD56dimCD16+ natural killer cells and immature dendritic cells. The increase of Th1/Th2 and Th17/Treg cells leads to preterm birth. Women with preterm birth had a higher proportion of decidual B cells. ILC2 can help protect the steady-state environment at the maternal-fetal interface. The activation of invariant NKT cells plays an important role in inflammation-induced preterm birth. These decidual immune cells communicate with each other. The development of sequencing technology enables a more in-depth study of decidual immune cells.

CONCLUSION

The dynamic balance of the maternal-fetal immune microenvironment plays a crucial role in maintaining human pregnancy and in the initiation of delivery. A deep understanding of the mechanism of decidual immune dysfunction is crucial for understanding the pathogenesis of preterm birth.

The modeling of human implantation and early placentation: achievements and perspectives

BACKGROUND

Successful implantation is a critical step for embryo survival. The major losses in natural and assisted human reproduction appeared to occur during the peri-implantation period. Because of ethical constraints, the fascinating maternal-fetal crosstalk during human implantation is difficult to study and thus, the possibility for clinical intervention is still limited.

OBJECTIVE AND RATIONALE

This review highlights some features of human implantation as a unique, ineffective and difficult-to-model process and summarizes the pros and cons of the most used in vivo, ex vivo and in vitro models. We point out the variety of cell line-derived models and how these data are corroborated by well-defined primary cells of the same nature. Important aspects related to the handling, standardization, validation, and modus operandi of the advanced 3D in vitro models are widely discussed. Special attention is paid to blastocyst-like models recapitulating the hybrid phenotype and HLA profile of extravillous trophoblasts, which are a unique yet poorly understood population with a major role in the successful implantation and immune mother-embryo recognition. Despite raising new ethical dilemmas, extended embryo cultures and synthetic embryo models are also in the scope of our review.

SEARCH METHODS

We searched the electronic database PubMed from inception until March 2024 by using a multi-stage search strategy of MeSH terms and keywords. In addition, we conducted a forward and backward reference search of authors mentioned in selected articles.

OUTCOMES

Primates and rodents are valuable in vivo models for human implantation research. However, the deep interstitial, glandular, and endovascular invasion accompanied by a range of human-specific factors responsible for the survival of the fetus determines the uniqueness of the human implantation and limits the cross-species extrapolation of the data. The ex vivo models are short-term cultures, not relevant to the period of implantation, and difficult to standardize. Moreover, the access to tissues from elective terminations of pregnancy raises ethical and legal concerns. Easy-to-culture cancer cell lines have many limitations such as being prone to spontaneous transformation and lacking decent tissue characteristics. The replacement of the original human explants, primary cells or cancer cell lines with cultures of immortalized cell lines with preserved stem cell characteristics appears to be superior for in vitro modeling of human implantation and early placentation. Remarkable advances in our understanding of the peri-implantation stages have also been made by advanced three dimensional (3D) models i.e. spheroids, organoids, and assembloids, as placental and endometrial surrogates. Much work remains to be done for the optimization and standardization of these integrated and complex models. The inclusion of immune components in these models would be an asset to delineate mechanisms of immune tolerance. Stem cell-based embryo-like models and surplus IVF embryos for research bring intriguing possibilities and are thought to be the trend for the next decade for in vitro modeling of human implantation and early embryogenesis. Along with this research, new ethical dilemmas such as the moral status of the human embryo and the potential exploitation of women consenting to donate their spare embryos have emerged. The careful appraisal and development of national legal and ethical frameworks are crucial for better regulation of studies using human embryos and embryoids to reach the potential benefits for human reproduction.

WIDER IMPLICATIONS

We believe that our data provide a systematization of the available information on the modeling of human implantation and early placentation and will facilitate further research in this field. A strict classification of the advanced 3D models with their pros, cons, applicability, and availability would help improve the research quality to provide reliable outputs.

Extra-embryonic mesoderm during development and in in vitro models

Extra-embryonic tissues provide protection and nutrition in vertebrates, as well as a connection to the maternal tissues in mammals. The extra-embryonic mesoderm is an essential and understudied germ layer present in amniotes. It is involved in hematopoiesis, as well as in the formation of extra-embryonic structures such as the amnion, umbilical cord and placenta. The origin and specification of extra-embryonic mesoderm are not entirely conserved across species, and the molecular mechanisms governing its formation and function are not fully understood. This Review begins with an overview of the embryonic origin and function of extra-embryonic mesoderm in vertebrates from in vivo studies. We then compare in vitro models that generate extra-embryonic mesoderm-like cells. Finally, we discuss how insights from studying both embryos and in vitro systems can aid in designing even more advanced stem cell-based embryo models.

Gestational exposure to nanoplastics disrupts fetal development by promoting the placental aging via ferroptosis of syncytiotrophoblast

Micro(nano)plastics (MNPs), are emerging environmental pollutants that have garnered widespread attention. Epidemiological and animal studies have shown that MNPs exposure during pregnancy is associated with adverse pregnancy outcomes, such as intrauterine growth restriction (IUGR) and miscarriage. However, the underlying mechanisms remain poorly understood. In this study, we found that exposure to a high dose (1 μg·mL-1) of 100 nm polystyrene nanoparticles (NPs) from gestational day (GD) 0 to GD17 significantly decreased fetal weight and increased the number of resorptions compared to the control group. Moreover, fetal weight was significantly lower in the high-dose group than in the low-dose (0.1 μg·mL-1) group. Meanwhile, ferroptosis and senescence were observed in placentas from mice exposed to high dose of NPs. In vitro experiments using human syncytiotrophoblast (STB) cells differentiated from BeWo cells, we found that NPs caused ferroptosis and senescence in STB cells. Subsequent investigations revealed that the inhibition of the ferroptosis signaling by ferrostain-1 (Fer-1) or deferiprone (DFP) ameliorated senescence induced by NPs in human STB cells. Furthermore, alleviating placental senescence using Fer-1 significantly improves fetal weight loss caused by NPs exposure during pregnancy in mice. Taken together, our results demonstrated that NPs exposure during pregnancy activated the ferroptosis pathway in placental STB, resulting in senescence of STB, which may attribute to the NPs-induced IUGR. This study not only elucidated the mechanistic link between NPs exposure and adverse pregnancy outcomes but also highlighted the necessity for targeted interventions to protect fetal health, underscoring the broader implications for environmental and public health policy.

Comparative analysis of the syncytiotrophoblast in placenta tissue and trophoblast organoids using snRNA sequencing

The outer surface of chorionic villi in the human placenta consists of a single multinucleated cell called the syncytiotrophoblast (STB). The unique cellular ultrastructure of the STB presents challenges in deciphering its gene expression signature at the single-cell level, as the STB contains billions of nuclei in a single cell. There are many gaps in understanding the molecular mechanisms and developmental trajectories involved in STB formation and differentiation. To identify the underlying control of the STB, we performed comparative single nucleus (SN) and single cell (SC) RNA sequencing on placental tissue and tissue-derived trophoblast organoids (TOs). We found that SN RNA sequencing was essential to capture the STB population from both tissue and TOs. Differential gene expression and pseudotime analysis of TO-derived STB identified three distinct nuclear subtypes reminiscent of those recently identified in vivo . These included a juvenile nuclear population that exhibited both CTB and STB marker expression, a population enriched in genes involved in oxygen sensing, and finally a subtype enriched in transport and GTPase signaling molecules. Notably, suspension culture conditions of TOs that restore the native orientation of the STB (STB out ) showed elevated expression of canonical STB markers and pregnancy hormones, along with a greater proportion of the STB nucleus subtype specializing in transport and GTPase signaling, compared to those cultivated with an inverted STB polarity (STB in ). Gene regulatory analysis identified novel markers of STB differentiation conserved in tissue and TOs, including the chromatin remodeler RYBP, that exhibited STB-specific RNA and protein expression. CRISPR/Cas9 knockout of RYBP in STB in TOs did not impact cell-cell fusion; however, bulk RNA sequencing revealed downregulation of the pregnancy hormone CSH1 and upregulation of multiple genes associated with the oxygen-sensing STB nuclear subtype. Finally, we compared STB gene expression signatures amongst first trimester tissue, full-term tissue, and TOs, identifying many commonalities but also notable variability across each sample type. This indicates that STB gene expression is responsive to its environmental context. Our findings emphasize the utility of TOs to accurately model STB differentiation and the distinct nuclear subtypes observed in vivo , offering a versatile platform for unraveling the molecular mechanisms governing STB functions in placental biology and disease.

Integral Roles of the TGFβ Signaling Pathway in Uterine Function and Disease

The uterus is a complex organ that requires precise signaling networks to mediate functions necessary for homeostasis and reproductive processes. The transforming growth factor β (TGFβ) superfamily regulates integral signaling pathways throughout many physiological processes, including cell proliferation, differentiation, and development. In this review, we summarize the current understanding of how the TGFβ signaling family controls key uterine functions, with a specific focus on the endometrium. These uterine functions include endometrial receptivity, implantation, decidualization, placentation, remodeling, and regeneration. Improving our understanding of the signaling networks that regulate these processes is integral to identifying, diagnosing, and treating uterine and reproductive diseases such as endometriosis, adenomyosis, recurrent pregnancy loss, and recurrent implantation failure.

Maternal circadian rhythms during pregnancy dictate metabolic plasticity in offspring

Tissue-level oscillation is achieved by tissue-intrinsic clocks along with network-dependent signals originating from distal organs and organismal behavior. Yet, it remains unexplored whether maternal circadian rhythms during pregnancy influence fetal rhythms and impact long-term susceptibility to dietary challenges in offspring. Here, we demonstrate that circadian disruption during pregnancy decreased placental and neonatal weight yet retained transcriptional and structural maturation. Intriguingly, diet-induced obesity was exacerbated in parallel with arrhythmic feeding behavior, hypothalamic leptin resistance, and hepatic circadian reprogramming in offspring of chronodisrupted mothers. In utero circadian desynchrony altered the phase-relationship between the mother and fetus and impacted placental efficiency. Temporal feeding restriction in offspring failed to fully prevent obesity, whereas the circadian alignment of caloric restriction with the onset of the active phase virtually ameliorated the phenotype. Thus, maternal circadian rhythms during pregnancy confer adaptive properties to metabolic functions in offspring and provide insights into the developmental origins of health and disease.

Irisin Improves Preeclampsia by Promoting Embryo Implantation and Vascular Remodeling

BACKGROUND

Preeclampsia is a pregnancy-specific disorder with unclear pathogenesis. Irisin, a recently identified exercise-induced factor, significantly influences lipid metabolism and cardiovascular function. Nonetheless, its role in trophoblast development during human placentation and the related intracellular signaling pathways remain poorly understood.

METHODS

We assessed peripheral blood irisin expression in early pregnancy among patients with preeclampsia and its correlation with key clinical indicators. In trophoblast cell lines and mice, we used exogenous irisin and viral knockdown to investigate functional changes. Phosphorylation-specific antibody arrays and dual-luciferase reporter assays were used to explore downstream molecular mechanisms, which were subsequently validated in trophoblast cell lines and relevant gene knockout mice.

RESULTS

In early pregnancy, patients with preeclampsia exhibit decreased peripheral blood irisin levels, occurring earlier than traditional predictive markers, such as PLGF (placental growth factor) and sFlt-1 (soluble fms-like tyrosine kinase-1). Furthermore, irisin concentration is positively correlated with proteinuria and abnormal blood pressure during pregnancy. Exogenous irisin significantly enhanced trophoblast cell migration, invasion, and proliferation while inhibiting apoptosis. It also increased STAT (signal transducers and activators of transcription) 4 phosphorylation and its binding to the GLUT (glucose transporter)-3 promoter, resulting in elevated GLUT-3 expression and glucose uptake in trophoblast cells. In vivo, increased peripheral irisin promoted embryo implantation, vascular remodeling, and enhanced glucose uptake, whereas reduced irisin resulted in a preeclampsia-like phenotype characterized by elevated blood pressure, proteinuria, renal-placental dysfunction, adipose accumulation, and restricted fetal growth.

CONCLUSIONS

Peripheral irisin improves preeclampsia by promoting embryo implantation and vascular remodeling through the activation of the STAT4/GLUT-3 pathway. Reduced peripheral irisin may contribute to preeclampsia-like pathologies. This study supports the advocacy for appropriate exercise during early pregnancy and provides new insights for preeclampsia prevention.

Developing a ceRNA-based lncRNA-miRNA-mRNA regulatory network to uncover roles in skeletal muscle development

The precise role of lncRNAs in skeletal muscle development and atrophy remain elusive. We conducted a bioinformatic analysis of 26 GEO datasets from mouse studies, encompassing embryonic development, postnatal growth, regeneration, cell proliferation, and differentiation, using R and relevant packages (limma et al.). LncRNA-miRNA relationships were predicted using miRcode and lncBaseV2, with miRNA-mRNA pairs identified via miRcode, miRDB, and Targetscan7. Based on the ceRNA theory, we constructed and visualized the lncRNA-miRNA-mRNA regulatory network using ggalluvial among other R packages. GO, Reactome, KEGG, and GSEA explored interactions in muscle development and regeneration. We identified five candidate lncRNAs (Xist, Gas5, Pvt1, Airn, and Meg3) as potential mediators in these processes and microgravity-induced muscle wasting. Additionally, we created a detailed lncRNA-miRNA-mRNA regulatory network, including interactions such as lncRNA Xist/miR-126/IRS1, lncRNA Xist/miR-486-5p/GAB2, lncRNA Pvt1/miR-148/RAB34, and lncRNA Gas5/miR-455-5p/SOCS3. Significant signaling pathway changes (PI3K/Akt, MAPK, NF-κB, cell cycle, AMPK, Hippo, and cAMP) were observed during muscle development, regeneration, and atrophy. Despite bioinformatics challenges, our research underscores the significant roles of lncRNAs in muscle protein synthesis, degradation, cell proliferation, differentiation, function, and metabolism under both normal and microgravity conditions. This study offers new insights into the molecular mechanisms governing skeletal muscle development and regeneration.

Increased cardiac macrophages in Sorbs2-deficient hearts: revealing a potential role for macrophage in responding to embryonic myocardial abnormalities

Macrophages are known to support cardiac development and homeostasis, contributing to tissue remodeling and repair in the adult heart. However, it remains unclear whether embryonic macrophages also respond to abnormalities in the developing heart. Previously, we reported that the structural protein Sorbs2 promotes the development of the second heart field, with its deficiency resulting in atrial septal defects (ASD). In analyzing RNA-seq data, we noted an upregulation of macrophage-related genes in Sorbs2 -/- hearts. Immunostaining and lineage-tracing confirmed an increase in macrophage numbers, underscoring a macrophage response to myocardial abnormalities. Partial depletion of macrophages led to downregulation of genes involved in lipid metabolism, muscle development and organ regeneration, alongside upregulation of genes associated with DNA damage-induced senescence and cardiomyopathy. Additionally, a non-significant increase in septal defects in macrophage-depleted Sorbs2 -/- hearts suggests a potential reparative function for macrophages in maintaining structural integrity. Valve formation, however, remained unaffected. Our findings suggest that embryonic macrophages might sense abnormalities in embryonic cardiomyocytes and could adaptively support cardiac structure and function development in response to myocardial abnormalities.

Neuroactive steroid exposure impacts neurodevelopment: Comparison of human and rodent placental contribution

The placenta is a fetal endocrine organ that secretes many neuroactive factors, including steroids, that play critical roles in brain development. The study of the placenta-brain axis and the links between placental function and brain development represents an emerging research area dubbed "neuroplacentology." The placenta drives many circulating fetal steroids to very high levels during gestation. Recent studies have highlighted the critical role of placental steroids in shaping specific brain structures and behaviors. This review uses a cross-species framework to discuss the genomic factors, in-utero environmental changes, and placental conditions that alter placental steroidogenesis, leading to changes in early developmental trajectories relevant for psychiatric conditions such as autism, in a sex-linked manner.

GATA1-mediated macrophage polarization via TrkB/cGMP-PKG signaling pathway to promote the development of preeclampsia

BACKGROUND

Preeclampsia (PE) is a severe pregnancy complication characterized by hypertension and proteinuria. PE poses a substantial threat to the health of both mothers and fetuses, and currently, there is no definitive treatment available. Recent studies have indicated that the transcription factor GATA1 may be implicated in the pathological processes of PE, but the underlying mechanism remains elusive. NTRK2/cGMP-PKG signaling pathway plays a crucial role in regulating the function and polarization of macrophages, which are key immune cells at the maternal-fetal interface. This study aims to investigate the role of GATA1 in the pathogenesis of PE, with a specific focus on how GATA1-regulated TrkB/cGMP-PKG signaling in macrophages and its dysregulation contribute to the development of preeclampsia.

METHODS

By employing THP-1 cells, co-culture systems of THP-1 cells and HTR-8/Svneo, HPVECs and Sprague-Dawley (SD) rats, in conjunction with gene knockdown and overexpression techniques, we explored the effects of GATA1 on the TrkB/cGMP-PKG signaling pathway. Transcriptomic sequencing, bioinformatics analysis, animal experiments, and clinical sample collection were conducted to validate the role of GATA1 in PE.

RESULTS

Knockdown of GATA1 mitigated the symptoms of PE, and this effect was reversed by overexpression of TrkB. In comparison with the control group, the proportion of M2 cells elevated significantly in the sh-GATA1 group (P < 0.001). In addition, the protein expressions levels of TrkB, cGMP, and PKG were significantly decreased in the sh-GATA1 group were significantly decreased compared with those in the control group (P < 0.001, P < 0.001, P < 0.001, P < 0.05, respectively). Moreover, knockdown of GATA1 significantly promoted the migration rate and blood vessel formation of HTR-8/Svneo cells (P < 0.001, P < 0.05, respectively) which inhibited by overexpression of NTRK2 (P < 0.05, P < 0.01, respectively).

CONCLUSIONS

The study demonstrated that knockdown of GATA1 modulates M2 polarization of macrophage through the TrkB/cGMP-PKG signaling pathway, influencing the progression of PE. In addition, significant associations between GATA1 and the TrkB/cGMP-PKG signaling pathway were identified in the transcriptomic data from PE patient placentas.

Single-cell RNA sequencing identifies CXADR as a fate determinant of the placental exchange surface

The placenta is the critical interface between mother and fetus, and consequently, placental dysfunction underlies many pregnancy complications. Placental formation requires an adequate expansion of trophoblast stem and progenitor cells followed by finely tuned lineage specification events. Here, using single-cell RNA sequencing of mouse trophoblast stem cells during the earliest phases of differentiation, we identify gatekeepers of the stem cell state, notably Nicol1, and uncover unsuspected trajectories of cell lineage diversification as well as regulators of lineage entry points. We show that junctional zone precursors and precursors of one of the two syncytial layers of the mouse placental labyrinth, the Syncytiotrophoblast-I lineage, initially share similar trajectories. Importantly, our functional analysis of one such lineage precursor marker, CXADR, demonstrates that this cell surface protein regulates the differentiation dynamics between the two syncytial layers of the mouse labyrinth, ensuring the correct establishment of the placental exchange surface. Deciphering the mechanisms underlying trophoblast lineage specification will inform our understanding of human pregnancy in health and disease.

Off to a good start: The importance of the placental exchange surface - Lessons from the mouse

The role of the chorio-allantoic placenta as the critical nutrient- and oxygen-supplying organ to nourish the demands of the fetus has been well recognized. This function relies on the successful establishment of the placental feto-maternal exchange unit, or interhaemal barrier, across which all nutrients as well as waste products must pass to cross from the maternal to the fetal blood circulation, or vice versa, respectively. As a consequence, defects in the establishment of this elaborate interface lead to fetal growth retardation or even embryonic lethality, depending on the severity of the defect. Beyond this essential role, however, it has also emerged that the functionality of the feto-maternal interface dictates the proper development of specific embryonic organs, with tightest links observed to the formation of the heart. In this article, we build on the foundational strength of the mouse as experimental model in which the placental causality of embryonic defects can be genetically proven. We discuss in detail the formation of the interhaemal barrier that makes up the labyrinth layer of the murine placenta, including insights into drivers of its formation and the interdependence of the cell types that make up this essential interface, from in vivo and in vitro data using mouse trophoblast stem cells. We highlight mouse genetic tools that enable the elucidation of cause-effect relationships between defects driven by either the trophoblast cells of the placenta or by embryonic cell types. We specifically emphasize gene knockouts for which a placental causality of embryonic heart defects has been demonstrated. This in-depth perspective provides much-needed insights while highlighting remaining gaps in knowledge that are essential for gaining a better understanding of the multi-facetted roles of the placenta in setting us up for a healthy start in life well beyond nutritional support alone.

Associations between metal/metalloid exposure during pregnancy and placental growth characteristics: Findings from the Hangzhou birth cohort study II

Previous studies have suggested that metal/metalloid (hereafter referred to as metal) exposure may influence placental growth by affecting gene expression in the placenta. However, no epidemiological studies have been conducted to validate the relationships between metals exposure, placental gene expression, and placental growth at the population level. This study aims to investigate these relationships based on Hangzhou birth cohort study II (HBCS-II). Totally, 1025 participants were derived from HBCS-II. Thirteen metals levels in the placenta were measured using inductively coupled plasma mass spectrometry. Placental growth characteristics were assessed, including placental weight, chorionic disc area, placental eccentricity, and distance from cord insertion site to the nearest edge of placenta (DCIEP). The relationships between metals exposure and placental growth characteristics were examined using the elastic net model combined unpenalized linear regression model. Placental gene expression levels were analyzed through RNA sequencing and real-time polymerase chain reaction (RT-qPCR), and mediation analysis was conducted to investigate whether placental gene expression could mediate the relationship between metal exposure and placental growth. Notably, the results showed that a unite increase in Ln-transformed cadmium (Cd) levels was associated with a reduction of 16.4 g [95% confidence interval (CI): 31.2, -1.5] in placental weight, 13.9 cm2 (95%CI: 20.0, -7.8) in chorionic disc area, and 0.3 cm (95%CI: 0.55, -0.06) in DCIEP. Through RNA sequencing followed by validation, significant associations were observed between placental Cd level and increased expression of placental genes, including TNFAIP2, OLAH, FLT4, SH3PXD2A, LIMCH1, BCL6, SLCO2A1, and CPSF1. Additionally, increased placental TNFAIP2, OLAH, FLT4, SH3PXD2A and LIMCH1 expression was linked to reduced placental weight. Moreover, SH3PXD2A was associated with decreased chorionic disc area. Mediation analysis showed that placental Cd level was associated with a 12.0 g (95%CI: 23.8, -2.7) decrease in placental weight mediated through the upregulation of FTL4 gene expression. The study provides evidence of the association between placental Cd exposure and decreased placental weight, and the FLT4 gene may play a mediating role in this relationship. Future experiment studies should be performed to validate the results.

DNA methylation in mammalian development and disease

The DNA methylation field has matured from a phase of discovery and genomic characterization to one seeking deeper functional understanding of how this modification contributes to development, ageing and disease. In particular, the past decade has seen many exciting mechanistic discoveries that have substantially expanded our appreciation for how this generic, evolutionarily ancient modification can be incorporated into robust epigenetic codes. Here, we summarize the current understanding of the distinct DNA methylation landscapes that emerge over the mammalian lifespan and discuss how they interact with other regulatory layers to support diverse genomic functions. We then review the rising interest in alternative patterns found during senescence and the somatic transition to cancer. Alongside advancements in single-cell and long-read sequencing technologies, the collective insights made across these fields offer new opportunities to connect the biochemical and genetic features of DNA methylation to cell physiology, developmental potential and phenotype.

Pregnancy in obese women and mechanisms of increased cardiovascular risk in offspring

Pregnancy complicated by maternal obesity contributes to an increased cardiovascular risk in offspring, which is increasingly concerning as the rates of obesity and cardiovascular disease are higher than ever before and still growing. There has been much research in humans and preclinical animal models to understand the impact of maternal obesity on offspring health. This review summarizes what is known about the offspring cardiovascular phenotype, describing a mechanistic role for oxidative stress, metabolic inflexibility, and mitochondrial dysfunction in mediating these impairments. It also discusses the impact of secondary postnatal insults, which may reveal latent cardiovascular deficits that originated in utero. Finally, current interventional efforts and gaps of knowledge to limit the developmental origins of cardiovascular dysfunction in offspring of obese pregnancy are highlighted.

Increased EHD1 in trophoblasts causes RSM by activating TGFβ signaling†

BACKGROUND

Recurrent spontaneous miscarriage is one of the complications during pregnancy. However, the pathogenesis of recurrent spontaneous miscarriage is far from fully elucidated.

OBJECTIVE

Since the endocytic pathway is crucial for cellular homeostasis, our study aimed to explore the roles of endocytic recycling, especially EH domain containing 1, a member of the endocytic recycling compartment, in recurrent spontaneous miscarriage.

STUDY DESIGN

We first investigated the expression of the endocytic pathway member EH domain containing 1 in villi from the normal and recurrent spontaneous miscarriage groups. Then, we performed ribonucleic acid sequencing and experiments in villi, HTR8 cells and BeWo cells to determine the mechanisms by which EH domain containing 1-induced recurrent spontaneous miscarriage. Finally, placenta-specific EH domain containing 1-overexpressing mice were generated to investigate the recurrent spontaneous miscarriage phenotype in vivo.

RESULTS

EH domain containing 1 was expressed in extravillous trophoblasts and syncytiotrophoblast in the villi. Compared with the control group, recurrent spontaneous miscarriage patients expressed higher EH domain containing 1. A high level of EH domain containing 1 decreased proliferation, promoted apoptosis, and reduced the migration and invasion of HTR8 cells by activating the TGFβ receptor 1-SMAD2/3 signaling pathway. The TGFβ receptor 1 antagonist LY3200882 partially reversed the EH domain containing 1 overexpression-induced changes in the cell phenotype. Besides, a high level of EH domain containing 1 also induced abnormal syncytialization, which disturbed maternal-fetal material exchanges. In a mouse model, placenta-specific overexpression of EH domain containing 1 led to the failure of spiral artery remodeling, excessive syncytialization, and miscarriage.

CONCLUSIONS

Increased expression of EH domain containing 1 impaired the invasion of extravillous trophoblasts mediated by the TGFβ receptor 1-SMAD2/3 signaling pathway and induced abnormal syncytialization of syncytiotrophoblast, which is at least partially responsible for recurrent spontaneous miscarriage.

Wnt signaling activation confers a syncytiotrophoblast progenitor state on trophoblast stem cells of cynomolgus monkey†

Trophoblast stem cells, derived from the trophectoderm of the blastocyst, are used as an in vitro model to reveal the mechanisms underlying placentation in mammals. In humans, suitable culture conditions for trophoblast stem cell derivation have recently been established. The established human trophoblast stem cells differentiate efficiently toward two trophoblast subtypes: syncytiotrophoblasts and extravillous trophoblasts. However, the efficiency of differentiation is lower in macaque trophoblast stem cells than in human trophoblast stem cells. Here, we demonstrate that the activation of Wnt signaling downregulated the expression of inhibitory G protein and induced trophoblastic lineage switching to the syncytiotrophoblast progenitor state. The treatment of macaque trophoblast stem cells with a GSK-3 inhibitor, CHIR99021, upregulated syncytiotrophoblast progenitor markers and enhanced proliferation. Under the Wnt signaling-activated conditions, macaque trophoblast stem cells effectively differentiated to syncytiotrophoblasts upon dibutyryl cyclic AMP (dbcAMP) and forskolin treatment. RNA-seq analyses revealed the downregulation of inhibitory G protein, which may make macaque trophoblast stem cells responsive to forskolin. Interestingly, this lineage switching appeared to be reversible as the macaque trophoblast stem cells lost responsiveness to forskolin upon the removal of CHIR99021. The ability to regulate the direction of macaque trophoblast stem cell differentiation would be advantageous in elucidating the mechanisms underlying placentation in non-human primates.

Treg cells promote decidual vascular remodeling and modulate uterine NK cells in pregnant mice

Regulatory T (Treg) cells are essential for maternal immune tolerance of the fetus and placenta. In preeclampsia, aberrant Treg cell tolerance is implicated, but how Treg cells affect the uterine vascular dysfunction thought to precede placental impairment and maternal vasculopathy is unclear. We used Foxp3-diphtheria toxin receptor mice to test the hypothesis that Treg cells are essential regulators of decidual spiral artery adaptation to pregnancy. Transient Treg cell depletion during early placental morphogenesis caused impaired remodeling of decidual spiral arteries, altered uterine artery function, and fewer Dolichos biflorus agglutinin+ uterine natural killer (uNK) cells, resulting in late-gestation fetal loss and fetal growth restriction. Replacing the Treg cells by transfer from wild-type donors mitigated the impact on uNK cells, vascular remodeling, and fetal loss. RNA sequencing of decidua revealed genes associated with NK cell function and placental extravillous trophoblasts were dysregulated after Treg cell depletion and normalized by Treg cell replacement. These data implicate Treg cells as essential upstream drivers of uterine vascular adaptation to pregnancy, through a mechanism likely involving phenotypic regulation of uNK cells and trophoblast invasion. The findings provide insight into mechanisms linking impaired adaptive immune tolerance and altered spiral artery remodeling, 2 hallmark features of preeclampsia.

TFAP2C is a key regulator of intrauterine trophoblast cell invasion and deep hemochorial placentation

Transcription factor AP-2 gamma (TFAP2C) has been identified as a key regulator of the trophoblast cell lineage and hemochorial placentation. The rat possesses deep placentation characterized by extensive intrauterine trophoblast cell invasion, which resembles human placentation. Tfap2c is expressed in multiple trophoblast cell lineages, including invasive trophoblast cells situated within the uterine-placental interface of the rat placentation site. Global genome editing was used to explore the biology of Tfap2c in rat placenta development. Homozygous global disruption of Tfap2c resulted in prenatal lethality. Heterozygous global disruption of Tfap2c was associated with diminished invasive trophoblast cell infiltration into the uterus. The role of TFAP2C in the invasive trophoblast cell lineage was explored using Cre-lox conditional mutagenesis. Invasive trophoblast cell-specific disruption of Tfap2c resulted in inhibition of intrauterine trophoblast cell invasion and intrauterine and postnatal growth restriction. The invasive trophoblast cell lineage was not impaired following conditional monoallelic disruption of Tfap2c. In summary, TFAP2C contributes to the progression of distinct stages of placental development. TFAP2C is a driver of early events in trophoblast cell development and reappears later in gestation as an essential regulator of the invasive trophoblast cell lineage. A subset of TFAP2C actions on trophoblast cells are dependent on gene dosage.

Dose-, stage- and sex- difference of prenatal prednisone exposure on placental morphological and functional development

Prednisone, a synthetic glucocorticoid, is commonly used to treat autoimmune diseases in pregnant women. However, some studies suggest that the use of prednisone during pregnancy may lead to adverse pregnancy outcomes. In this study, we established PPE mouse models at different doses (0.25, 0.5, 1.0 mg/kg·d) and different stages (whole pregnancy, early pregnancy and middle-late pregnancy) and determined outcomes on the placenta and fetus. The results of our study indicated that at the highest dose of 1 mg/kg PPE using a GD 0-18 dosing regime, PPE caused placental morphological changes measured as a decrease in placental weight relative to controls and a decrease in the placenta junctional zone (JZ)/labyrinth zone (LZ) ratio. No changes were observed on the fetuses for number of live, stillborn, and absorbed fetuses between the experimental groups and the control group. In the placentas at some doses, there were decreases in cell proliferation markers measured at the RNA and protein level by Western blot and increased apoptosis. Measures of gene expression at the mRNA level showed altered nutrients (including glucose, amino acid, and cholesterol) transport gene expressions with the most significant change associated with the male placentas at high-dose and whole pregnancy PPE group. It was further found that PPE led to the inhibition of the insulin-like growth factor 2 (IGF2)/insulin-like growth factor 1 receptor (IGF1R) signaling pathway, which was well correlated with the indicators of cell proliferation, syncytialization and nutrient (glucose and amino acid) transport indices. In conclusion, PPE can alter placental morphology and nutrient transport function, with differences in effect related to dose, stage and gender. Differential gene expressions measured for genes of the IGF2/IGF1R signaling pathway suggested this pathway may be involved in the effects seen with PPE. This study provides a theoretical and experimental basis for enhancing the understanding of the effects of prednisone use on placenta during human pregnancy but does not currently raise concerns for human use as effects were not seen on the fetuses and while the effects on cell proliferation are informative they were inconsistent and the differential effects on female and male placentas unexplained suggesting that further work is required to elucidate if these findings have relevance for human use of PPE during pregnancy.

METTL3 and IGF2BP2 coordinately regulate FOSL1 mRNA via m6A modification, suppressing trophoblast invasion and contributing to fetal growth restriction

Fetal growth restriction (FGR) increases the risk of short-term and long-term complications. Widespread N6-methyladenosine (m6A) modifications on mRNAs have been found to be involved in various biological processes. However, the role of m6A modification in the pathogenesis of FGR remains elusive. Here, we report that elevated levels of METTL3 and m6A modification were detected in FGR placentae. Functionally, cell migration, invasion, and proliferation abilities were suppressed after METTL3 overexpression in HTR8/SVneo cells. Subsequently, methylated RNA immunoprecipitation sequencing (MeRIP-seq) and RNA sequencing (RNA-seq) of METTL3-knockdown HTR8/SVneo cells were utilized together to identify FOSL1 as the downstream target genes of METTL3. Furthermore, we illustrated that METTL3-mediated m6A modification enhanced the expression of FOSL1 in a IGF2BP2 dependent manner. FOSL1 inhibited trophoblast invasion and migration. Importantly, STM2457, a novel METTL3 catalytic inhibitor, was intravenously administered to FGR mice models, which restore fetal and placental weights in vivo. In vitro STM2457 regulated trophoblast proliferation, invasion, and migration in a dose-dependent manner. In summary, this study reveals that METTL3 and IGF2BP2 increase FOSL1 expression in an m6A-dependent manner. The increase of FOSL1disrupts normal trophoblast invasion, which results in the progression of FGR. METTL3 can serve as a potential target for FGR therapy.

Determining the effects of paternal obesity on sperm chromatin at histone H3 lysine 4 tri-methylation in relation to the placental transcriptome and cellular composition

Paternal obesity has been implicated in adult-onset metabolic disease in offspring. However, the molecular mechanisms driving these paternal effects and the developmental processes involved remain poorly understood. One underexplored possibility is the role of paternally induced effects on placenta development and function. To address this, we investigated paternal high-fat diet-induced obesity in relation to sperm histone H3 lysine 4 tri-methylation signatures, the placenta transcriptome, and cellular composition. C57BL6/J male mice were fed either a control or high-fat diet for 10 weeks beginning at 6 weeks of age. Males were timed-mated with control-fed C57BL6/J females to generate pregnancies, followed by collection of sperm, and placentas at embryonic day (E)14.5. Chromatin immunoprecipitation targeting histone H3 lysine 4 tri-methylation (H3K4me3) followed by sequencing (ChIP-seq) was performed on sperm to define obesity-associated changes in enrichment. Paternal obesity corresponded with altered sperm H3K4me3 at promoters of genes involved in metabolism and development. Notably, altered sperm H3K4me3 was also localized at placental enhancers. Bulk RNA-sequencing on placentas revealed paternal obesity-associated sex-specific changes in expression of genes involved in hypoxic processes such as angiogenesis, nutrient transport, and imprinted genes, with a subset of de-regulated genes showing changes in H3K4me3 in sperm at corresponding promoters. Paternal obesity was also linked to impaired placenta development; specifically, a deconvolution analysis revealed altered trophoblast cell lineage specification. These findings implicate paternal obesity effects on placenta development and function as one potential developmental route to offspring metabolic disease.

TFAP2C is a key regulator of intrauterine trophoblast cell invasion and deep hemochorial placentation

Transcription factor AP-2 gamma ( TFAP2C ) has been identified as a key regulator of the trophoblast cell lineage and hemochorial placentation. The rat possesses deep placentation characterized by extensive intrauterine trophoblast cell invasion, which resembles human placentation. Tfap2c is expressed in multiple trophoblast cell lineages, including invasive trophoblast cells situated within the uterine-placental interface of the rat placentation site. Global genome-editing was used to explore the biology of Tfap2c in rat placenta development. Homozygous global disruption of Tfap2c resulted in prenatal lethality. Heterozygous global disruption of Tfap2c was associated with diminished invasive trophoblast cell infiltration into the uterus. The role of TFAP2C in the invasive trophoblast cell lineage was explored using Cre-lox conditional mutagenesis. Invasive trophoblast cell-specific disruption of Tfap2c resulted in inhibition of intrauterine trophoblast cell invasion and intrauterine and postnatal growth restriction. The invasive trophoblast cell lineage was not impaired following conditional monoallelic disruption of Tfap2c . In summary, TFAP2C contributes to the progression of distinct stages of placental development. TFAP2C is a driver of early events in trophoblast cell development and reappears later in gestation as an essential regulator of the invasive trophoblast cell lineage. A subset of TFAP2C actions on trophoblast cells are dependent on gene dosage.

SLC25A1 regulates placental development to ensure embryonic heart morphogenesis

22q11.2 deletion syndrome (22q11.2DS) is the most common chromosomal microdeletion syndrome. Congenital heart defects are prevalent in 22q11.2DS but the etiology is still poorly understood. In this study, we aimed to gain mechanistic insights into the heart defects that result from 22q11.2 deletion, with a focus on Slc25a1, which is located in the deletion segment. Whereas global knockout of Slc25a1 in mice produced a variety of heart malformations, cardiac deletion of Slc25a1 had little effect on heart development. We then found that trophoblast-specific Slc25a1 deletion recapitulated heart anomalies in the global knockout mice. Further study identified SLC25A1 as a regulator of trophoblast and placental development through modulation of histone H3K27 acetylation at the promoters and enhancers of key genes involved in trophoblast differentiation. Finally, administration of recombinant human pregnancy-specific glycoprotein 1 (PSG1), a trophoblast-derived secretory glycoprotein, partially corrected placental and embryonic heart defects. This study defines the role of SLC25A1 in heart development by regulating placental development, and provides new insights to understand the etiology of 22q11.2DS.

Identification of transcriptional signature change and critical transcription factors involved during the differentiation of mouse trophoblast stem cell into maternal blood vessel associated trophoblast giant cell

The placenta is essential organ for oxygen and nutrient exchange between the mother and the developing fetus. Trophoblast lineage differentiation is closely related to the normal function of the placenta. Trophoblast stem cells (TSCs) can differentiate into all placental trophoblast subtypes and are widely used as in vitro stem cell models to study placental development and trophoblast lineage differentiation. Although extensive research has been conducted on the differentiation of TSCs, the possible parallels between trophoblast giant cells (TGCs) that are differentiated from TSCs in vitro and the various subtypes of TGC lineages in vivo are still poorly understood. In this study, mouse TSCs (mTSCs) were induced to differentiate into TGCs, and our mRNA sequencing (RNA-seq) data revealed that mTSCs and TGCs have distinct transcriptional signatures. We conducted a comparison of mTSCs and TGCs transcriptomes with the published transcriptomes of TGC lineages in murine placenta detected by single-cell RNA-seq and found that mTSCs tend to differentiate into maternal blood vessel-associated TGCs in vitro. Moreover, we identified the transcription factor (TF) ZMAT1, which may be responsible for the differentiation of mTSCs into sinusoid TGCs, and the TFs EGR1 and MITF, which are likely involved in the differentiation of mTSCs into spiral artery-associated TGCs. Thus, our findings provide a valuable resource for the mechanisms of trophoblast lineage differentiation and placental deficiency-associated diseases development.

A spatiotemporal transcriptomic atlas of mouse placentation

The placenta, a temporary but essential organ for gestational support, undergoes intricate morphological and functional transformations throughout gestation. However, the spatiotemporal patterns of gene expression underlying placentation remain poorly understood. Utilizing Stereo-seq, we constructed a Mouse Placentation Spatiotemporal Transcriptomic Atlas (MPSTA) spanning from embryonic day (E) 7.5 to E14.5, which includes the transcriptomes of large trophoblast cells that were not captured in previous single-cell atlases. We defined four distinct strata of the ectoplacental cone, an early heterogeneous trophectoderm structure, and elucidated the spatial trajectory of trophoblast differentiation during early postimplantation stages before E9.5. Focusing on the labyrinth region, the interface of nutrient exchange in the mouse placenta, our spatiotemporal ligand-receptor interaction analysis unveiled pivotal modulators essential for trophoblast development and placental angiogenesis. We also found that paternally expressed genes are exclusively enriched in the placenta rather than in the decidual regions, including a cluster of genes enriched in endothelial cells that may function in placental angiogenesis. At the invasion front, we identified interface-specific transcription factor regulons, such as Atf3, Jun, Junb, Stat6, Mxd1, Maff, Fos, and Irf7, involved in gestational maintenance. Additionally, we revealed that maternal high-fat diet exposure preferentially affects this interface, exacerbating inflammatory responses and disrupting angiogenic homeostasis. Collectively, our findings furnish a comprehensive, spatially resolved atlas that offers valuable insights and benchmarks for future explorations into placental morphogenesis and pathology.

ALKBH5 modulation of ferroptosis in recurrent miscarriage: implications in cytotrophoblast dysfunction

Background

As one of the most common and abundant internal modifications of eukaryotic mRNA, N6-methyladenosine (m6A) modifications are closely related to placental development. Ferroptosis is a newly discovered form of programmed cell death. During placental development, placental trophoblasts are susceptible to ferroptosis. However, the interactions of m6A and ferroptosis in trophoblast physiology and injury are unclear.

Methods

Recurrent miscarriage (RM) was selected as the main gestational disease in this study. Published data (GSE76862) were used to analyze the gene expression profiles in patients with RM. The extent of m6A modification in total RNA of villous tissues between patients with RM and healthy controls (HC) was compared. ALKBH5 (encoding AlkB homolog 5, RNA demethylase) was selected as the candidate gene for further research. Quantitative real-time reverse transcription PCR, western blotting, and immunohistochemistry (IHC) confirmed the elevated expression of ALKBH5 in the cytotrophoblasts of patients with RM. Then, cell counting kit-8 assays, glutathione disulfide/glutathione quantification, 2',7'-dichlorfluorescein-diacetate staining, and malonaldehyde assays were used to explore the alterations of ferroptosis-related characteristics following RAS-selective lethal (RSL3) stimulation after overexpression of ALKBH5. Thereafter, we re-analyzed the published RNA sequencing data upon knockdown of ALKBH5, combined with published tissue RNA-seq data, and FTL (encoding ferritin light chain) was identified as the ferroptosis-related gene in cytotrophoblasts of patients with RM that is regulated by ALKBH5. Finally, western blotting and IHC confirmed the increased expression of FTL in the cytotrophoblasts from patients with RM.

Results

Total m6A levels were decreased in patients with RM. The most significant differentially m6A-related gene was ALKBH5, which was increased in patients with RM. In vitro cell experiments showed that treatment with RSL3 resulted in increased cell death and upregulated ALKBH5 expression. Overexpression of ALKBH5 alleviated RSL3-induced HTR8 cell death and caused decreased levels of intracellular oxidation products. Published transcriptome sequencing revealed that FTL was the major ferroptosis-related gene regulated by ALKBH5 in the villous tissues of patients with RM. Consistent with the expression of ALKBH5, FTL was increased by RSL3-induction and increased in patients with RM.

Conclusion

Elevated ALKBH5 alleviated RSL3-induced cytotrophoblast cell death by promoting the expression of FTL in patients with RM. Our results supported the view that ALKBH5 is an important regulator of the ferroptosis-related etiology of RM and suggested that ALKBH5 could be responsible for epigenetic aberrations in RM pathogenesis.

Early human development and stem cell-based human embryo models

The use of stem cells to model the early human embryo promises to transform our understanding of developmental biology and human reproduction. In this review, we present our current knowledge of the first 2 weeks of human embryo development. We first focus on the distinct cell lineages of the embryo and the derivation of stem cell lines. We then discuss the intercellular crosstalk that guides early embryo development and how this crosstalk is recapitulated in vitro to generate stem cell-based embryo models. We highlight advances in this fast-developing field, discuss current limitations, and provide a vision for the future.