Extravillous trophoblast migration and invasion: Impact of environmental chemicals and pharmaceuticals

MTHFD2: A metabolic checkpoint altering trophoblast invasion and migration by remodeling folate-nucleotide metabolism in recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) affects female reproduction worldwide, yet its pathological mechanisms are still unclear. It has been reported that cellular metabolism reprogramming is a critical step for trophoblasts during embryo implantation. Herein, MTHFD2 was recognized as a key metabolic checkpoint attributed to RSA occurrence. This work figured out that the expression level of MTHFD2 was significantly inhibited in villus tissues from RSA patients, suggesting the potential role of MTHFD2 in RSA occurrence. Moreover, MTHFD2 knockdown impaired cellular folate-nucleotide metabolism, induced the accumulation of AICAR, and thereby impairing the EMT process to inhibit the invasion and migration of trophoblasts Besides, the AICAR accumulation further activated the downstream AMPK which deactivated the JAK/STAT/Slug pathway and ultimately deactivated the EMT process. Using a mouse model, MTHFD2 inhibition was observed to induce embryo implantation failure in vivo. Our results highlighted MTHFD2 as a metabolic checkpoint that remodeled folate-nucleotide metabolism to regulate the EMT process and ultimately altered the migration and invasion of trophoblasts in RSA occurrence. Our findings suggested that MTHFD2 was a promising therapeutic target in recurrent spontaneous abortion treatment.

Stem cell models of human embryo implantation and trophoblast invasion

Stem cell-based embryo models have taken the scientific community by storm as they enable investigation of previously inaccessible stages of human development. Here, we discuss how stem cell-based embryo and placenta models can shine a light on two elusive and intertwined aspects of human development that are critical for successful pregnancy: the implantation of the blastocyst into the endometrium and the subsequent invasion of placental villi deep inside the maternal tissues. Both of these processes are mediated by the trophoblast lineage, which is specified in the preimplantation embryo and can be modeled using naïve pluripotent stem cells. We review how embryo and placenta models built from naïve stem cells can be leveraged to obtain mechanistic insights into human implantation and trophoblast invasion.

LC-MS/MS assay to confirm that the endogenous metabolite L-Arginine promotes trophoblast invasion in the placenta accreta spectrum through upregulation of the GPRC6A/PI3K/AKT pathway

OBJECTIVE

Placental accreta spectrum (PAS) is a collective term for a range of pregnancy complications caused by abnormal placental implantation, posing a threat to the lives of both the mother and the fetus. This study aimed to screen for placental marker metabolites of PAS and assess the effect of L-Arginine on trophoblast invasion.

METHODS

Placental tissues were collected from a total of 15 pregnant women, including 10 women diagnosed with PAS and 5 women with normal pregnancies. Histological staining was used to characterize pathological changes in the placenta. The changes in endogenous placental metabolites by LC-MS/MS. Subsequently, the role of marker metabolite L-Arginine on HTR-8/Svneo invasion was explored, and protein transcription and expression levels of GPRC6A/PI3K/AKT/MMP2/MMP9 were determined by RT-qPCR and western blot.

RESULTS

The placentas of PAS patients were mostly infiltrative invasion, with active proliferation and inhibited apoptosis of trophoblast cells. By LC-MS/MS, we identified 13 significantly different metabolites between healthy and PAS pregnant women's placenta tissue. Among them, placental concentrations of L-Arginine were significantly higher in PAS pregnant women than in controls. In vitro, L-Arginine promoted the proliferation and migration of HTR8/SVneo cells and upregulated the transcription and expression of proteins related to the GPRC6A/PI3K/AKT pathway.

CONCLUSIONS

Our study demonstrates that L-Arginine may promote trophoblast invasion and migration in placental implantation by upregulating the GPRC6A/PI3K/AKT pathway. This provides a new basis for screening appropriate metabolic markers for PAS, thus contributing to the prevention and treatment of PAS.

sCEACAM-1 levels in maternal blood in case of threatened preterm birth

INTRODUCTION

This study aims to investigate the role of CEACAM1 in preterm birth. Preterm birth is a phenomenon with numerous triggers, with the immune system hypothesized to play a significant role in the process, aligning with the concept of 'birth as an immunological rejection phenomenon'. There are several approaches to predict preterm birth, and the determination of sCEACAM1 levels, a member of the carcinoembryonic antigen family, may serve as a potential candidate biomarker.

METHODS

A single-center prospective case series study included 67 pregnant women aged 18 years or older who presented before 37 weeks of gestation with signs of preterm birth in the years 2021-2023. At the time of admission, CEACAM1 was determined in maternal blood.

RESULTS

The median sCEACAM1 levels were significantly higher in women who delivered preterm compared to those who delivered at term respectively, 5014 pg/ml (IQR: 3592-8826) vs. 3353 pg/ml (IQR: 2354-5049) (p = 0.016). The median sCEACAM1 level in the group with PPROM (premature preterm rupture of membranes) at 34 weeks' gestation was 7001 pg/ml (IQR: 5683-13509), while the median sCEACAM1 level in the group without PPROM at 34 weeks' gestation was 3884 pg/ml (IQR; 2461-4985) (p < 0.001).

CONCLUSIONS

Pregnant women with preterm birth and/or PPROM before 34 weeks' gestation have higher CEACAM1 levels compared to women with threatened preterm labor who finally had labot at term. The results suggest early activated immune system as a potential pathomechanism of preterm delivery.

PBX1 attenuates inflammation and apoptosis of trophoblast cells induced by LPS through downregulating the transcription of TMUB1: PBX1 ameliorates RSA development

Recurrent spontaneous abortion (RSA) brings tremendous difficulties to clinical treatment and prognosis. Pre-B-cell leukemia homeobox 1 (PBX1), as a functional transcription factor, involves in the regulation of cell apoptosis and proliferation. However, the underlying mechanism of PBX1 in RSA treatment has not been explored. We established a lipopolysaccharide (LPS)-induced abortion model and detected PBX1 expression with real-time PCR, western blot and immunohistochemistry. The PBX1-overexpressed adenovirus (AV-oePBX1) was infected into trophoblast cells treated with LPS to define the function of PBX1 on cell apoptosis, inflammation and NF-κB pathway. A luciferase reporter assay was conducted to validate the transcription regulation of PBX1 on transmembrane and ubiquitin like domain containing 1 (TMUB1). Compared to women with normal abortion, PBX1 was downregulated in the placental villous tissues of RSA patients. The placental tissues of LPS-treated mice also manifested notably reduction of PBX1 at mRNA and protein levels. PBX1 overexpression alleviated inflammation and apoptosis of trophoblast cells. Substantially, PBX1 was negatively correlated with TMUB1, which was highly expressed in RSA patients and LPS-treated mice. Moreover, PBX1 bound to TMUB1 promoter and inhibited its transcription. Interestingly, exogenous TMUB1 abolished the effects of PBX1 on apoptosis, inflammation, and NF-κB signal pathway. In total, PBX1 attenuated cell apoptosis and inflammation, and suppressed NF-κB signal pathway induced by LPS through downregulating TMUB1 transcription. Therefore, PBX1 may be developed as a novel target for clinical treatment of RSA.

Using transcriptomic signatures to elucidate individual and mixture effects of inorganic arsenic and manganese in human placental trophoblast HTR-8/SVneo cells

Prenatal exposure to the toxic metal inorganic arsenic (iAs) is associated with adverse pregnancy and fetal growth outcomes. These adverse outcomes are tied to physiological disruptions in the placenta. Although iAs co-occurs in the environment with other metals such as manganese (Mn), there is a gap in the knowledge of the effects of metal mixtures on the placenta. To address this, we exposed human placental trophoblast cells to iAs, Mn, and an iAs-Mn mixture at 3 concentrations and evaluated transcriptome-wide gene expression and placental migration. We hypothesized that co-exposure to iAs-Mn in a mixture would result in a synergistic/enhanced transcriptomic effect compared to either metal alone. We also anticipated that genes involved in inflammatory or immune-related pathways would be differentially expressed in relation to the mixture compared to single-metals. The results highlight that iAs exposure alone had a stronger genomic response than Mn exposure, with 2-fold the number of differentially expressed genes (DEGs). When analyzing DEGs present across all concentrations of study, the iAs-Mn mixture resulted in the greatest number of DEGs. The results highlight that iAs exposure alone influences the expression of toll-like receptor-initiated response pathways including Triggering Receptor Expressed on Myeloid Cells-1. Exposure to Mn alone influenced the expression of Nicotinamide adenine dinucleotide biosynthesis pathways. In contrast, exposure to the iAs-Mn mixtures resulted in altered expression of inflammatory and immune response-related pathways, including the Nuclear factor erythroid 2-related factor 2 (NRF2)-mediated oxidative stress response pathway. Migration was unaffected by iAs, Mn, or the iAs-Mn mixture. These findings provide novel toxicogenomic insights into iAs- and Mn-induced placental transcriptomic dysregulations at environmentally relevant concentrations, with implications that in utero exposure to metal mixtures can influence inflammatory and immune pathways within the placenta.

Simulated ischaemia/reperfusion impairs trophoblast function through divergent oxidative stress- and MMP-9-dependent mechanisms

Early-onset pre-eclampsia is believed to arise from defective placentation in the first trimester, leading to placental ischaemia/reperfusion (I/R) and oxidative stress. However, our current understanding of the effects of I/R and oxidative stress on trophoblast function is ambiguous in part due to studies exposing trophoblasts to hypoxia instead of I/R, and which report conflicting results. Here, we present a model of simulated ischaemia/reperfusion (SI/R) to recapitulate the pathophysiological events of early-onset pre-eclampsia (PE), by exposing first trimester cytotrophoblast HTR-8/SVneo cells to a simulated ischaemia buffer followed by reperfusion. We examined different ischaemia and reperfusion times and observed that 1 h ischaemia and 24 h reperfusion induced an increase in reactive oxygen species (ROS) production (P<0.0001) and oxygen consumption rate (P<0.01). SI/R-exposed trophoblast cells exhibited deficits in migration, proliferation, and invasion (P<0.01). While the deficits in migration and proliferation were rescued by antioxidants, suggesting an ROS-dependent mechanism, the loss of invasion was not affected by antioxidants, which suggests a divergent ROS-independent pathway. In line with this, we observed a decrease in MMP-9, the key regulatory enzyme necessary for trophoblast invasion (P<0.01), which was similarly unaffected by antioxidants, and pharmacological inhibition of MMP-9 replicated the phenotype of deficient invasion (P<0.01). Collectively, these data demonstrate that I/R impairs trophoblast migration and proliferation via a ROS-dependent mechanism, and invasion via an ROS-independent loss of MMP-9, disambiguating the role of oxidative stress and providing insights into the response of trophoblasts to I/R in the context of early-onset PE.

Decoding the molecular pathways governing trophoblast migration and placental development; a literature review

Placental development is a multifaceted process critical for a fruitful pregnancy, reinforced by a complex network of molecular pathways that synchronize trophoblast migration, differentiation, and overall placental function. This review provides an in-depth analysis of the key signaling pathways, such as Wnt, Notch, TGF-β, and VEGF, which play fundamental roles in trophoblast proliferation, invasion, and the complicated process of placental vascular development. For instance, the Wnt signaling pathway is essential to balance trophoblast stem cell proliferation and differentiation, while Notch signaling stimulates cell fate decisions and invasive behavior. TGF-β signaling plays a critical role in trophoblast invasion and differentiation, predominantly in response to the low oxygen environment of early pregnancy, regulated by hypoxia-inducible factors (HIFs). These factors promote trophoblast adaptation, ensure proper placental attachment and vascularization, and facilitate adequate fetal-maternal exchange. Further, we explore the epigenetic and post-transcriptional regulatory mechanisms that regulate trophoblast function, including DNA methylation and the contribution of non-coding RNAs, which contribute to the fine-tuning of gene expression during placental development. Dysregulation of these pathways is associated with severe pregnancy complications, such as preeclampsia, intrauterine growth restriction, and recurrent miscarriage, emphasizing the critical need for targeted therapeutic strategies. Finally, emerging technologies like trophoblast organoids, single-cell RNA sequencing, and placenta-on-chip models are discussed as innovative tools that hold promise for advancing our understanding of placental biology and developing novel interventions to improve pregnancy outcomes. This review emphasizes the importance of understanding these molecular mechanisms to better address placental dysfunctions and associated pregnancy disorders.

Blocking lactate regulation of the Grhl2/SLC31A1 axis inhibits trophoblast cuproptosis and preeclampsia development

PURPOSE

Abnormal cell death due to superficial trophoblast dysfunction caused by placental hypoxia plays a vital role in the development of preeclampsia (PE). Lactic acid stimulates gene transcription in chromatin through lactate modification of histone lysine. Nevertheless, the content and function of lactate in PE development remains largely unclear.

METHODS

The contents of lactic acid and copper in 30 PE and 30 normal placentas were determined by kit colorimetry. Real-time quantitative fluorescent PCR (qRT-PCR) and Western blot were used to detect the expression of SLC31A1 in cells and tissues. Cell proliferation, apoptosis, and invasion were detected by cell counting kit 8 (CCK-8), MTS assay, colony formation assay, and Transwell assay. The transcriptional regulation between Grhl2 and SLC31A was verified by the luciferase reporter gene method and ChIP. The H3K18la modification level was detected by ChIP-PCR.

RESULTS

Herein, we detected increased lactic acid levels in the PE placental tissue, which inhibit the proliferation and invasion of trophoblasts. Interestingly, lactic acid increases intracellular copper content by enhancing the expression of SLC31A1, a key protein of copper ion transporters. Lentivirus knockdown of SLC31A1 blocked the lactate-induced proliferation and invasion of trophoblasts by inhibiting cell cuproptosis. Mechanically, we identified that Grhl2 mediated SLC31A1 expression through transcription and participated in SLC31A1-inhibited proliferation, invasion, and cuproptosis of trophoblasts. Furthermore, the high lactate content increased Grhl2 expression by enhancing lactate modification of histone H3K18 in the Grhl2 promoter region.

CONCLUSIONS

Blocking the lactate-regulated Grhl2/SLC31A1 axis and trophoblastic cuproptosis may be a potential approach to prevent and treat PE.

Alpinumisoflavone ameliorates H2O2-induced intracellular damages through SIRT1 activation in pre-eclampsia cell models

Pre-eclampsia (PE) is classified as pregnancy-specific hypertensive disease and responsible for severe fetal and maternal morbidity and mortality, which influenced an approximate 3 ∼ 8 % of all pregnancies in both developed and developing countries. However, the exact pathological mechanism underlying PE has not been elucidated and it is urgent to find innovate pharmacotherapeutic agents for PE. Recent studies have reported that a crucial part of the etiology of PE is played by placental oxidative stress. Therefore, to treat PE, a possible treatment approach is to mitigate the placental oxidative stress. Alpinumisoflavone (AIF) is a prenylated isoflavonoid originated in mandarin melon berry called Cudrania tricuspidate, and is well known for its versatile pharmacotherapeutic properties, including anti-fibrotic, anti-inflammatory, anti-tumor, and antioxidant activity. However, protective property of AIF on extravillous trophoblast (EVT) under placental oxidative stress has not been elucidated yet. Therefore, we assessed stimulatory effects of AIF on the viability, invasion, migration, mitochondria function in the representative EVT cell line, HTR-8/SVneo cell. Moreover, protective activities of AIF from H2O2 were confirmed, in terms of reduction in apoptosis, ROS production, and depolarization of mitochondrial membrane. Furthermore, we confirmed the direct interaction of AIF with sirtuin1 (SIRT1) using molecular docking analysis and SIRT1-mediated signaling pathways associated with the protective effects of AIF on HTR-8/SVneo cells under oxidative stress. Finally, beneficial efficacy of AIF against oxidative stress was further confirmed using BeWo cells, syncytiotrophoblast cell lines. These results suggest that AIF may ameliorate H2O2-induced intracellular damages through SIRT1 activation in human trophoblast cells.

Hydroquinone impairs trophoblast migration and invasion via AHR-twist-IFITM1 axis

INTRODUCTION

Embryo implantation is a tightly regulated process, critical for a successful pregnancy. After attachment of the blastocyst to the surface epithelium of the endometrium trophoblast migrate from the trophectoderm and invade into the stromal component of endometrium. Alterations on either process will lead to implantation failure or miscarriage. Volatile organic compounds (VOCs) such as benzene induce pregnancy complications, including preterm birth and miscarriages. The mechanism of this effect is unknown. The objective of this study was to elucidate the impact of benzene metabolite, Hydroquinone, on trophoblast function. We tested the hypothesis that Hydroquinone activates the Aryl hydrocarbon receptor (AhR) pathway modulating trophoblast migration and invasion.

METHODS

First-trimester trophoblast cells (Sw.71) were treated with hydroquinone (6 and 25 μM). Trophoblast migration and invasion was evaluated using a 3D invasion/migration model. Gene expression was quantified by q-PCR and Western blot analysis.

RESULTS

Hydroquinone impairs trophoblast migration and invasion. This loss is associated with the activation of the AhR pathway which reduced the expression of Twist1and IFITM1. IFITM1 overexpression can rescue impaired trophoblast migration.

DISCUSSION

Our study highlights that hydroquinone treatment induces the activation of the AhR pathway in trophoblast cells, which impairs trophoblast invasion and migration. We postulate that activation of the AhR pathway in trophoblast suppress Twist1 and a subsequent IFITM1. Thus, the AhR-Twist1-IFITM1 axis represent a critical pathway involved in the regulation of trophoblast migration and it is sensitive to benzene exposure. These findings provide crucial insights into the molecular mechanisms underlying pregnancy complications induced by air pollution.

Infertility: Focus on the therapeutic potential of extracellular vesicles

Infertility is a well-known problem that arises from a variety of reproductive diseases. Until now, researchers have tried various methods to restore fertility, including medication specific to the cause, hormone treatments, surgical removals, and assisted reproductive technologies. While these methods do produce results, they do not consistently lead to fertility restoration in every instance. The use of exosome therapy has significant potential in treating infertility in patients. This is because exosomes, microvesicles, and apoptotic bodies, which are different types of vesicles, play a crucial role in transferring bioactive molecules that aid in cell-to-cell communication. Reproductive fluids can transport a variety of molecular cargos, such as miRNAs, mRNAs, proteins, lipids, and DNA molecules. The percentage of these cargos in the fluids can be linked to their physiological and pathological status. EVs are involved in several physiological and pathological processes and offer interesting non-cellular therapeutic possibilities to treat infertility. EVs (extracellular vesicles) transplantation has been shown in many studies to be a key part of regenerating different parts of the reproductive system, including the production of oocytes and the start of sperm production. Nevertheless, the existing evidence necessitates testifying to the effectiveness of injecting EVs in resolving reproductive problems among humans. This review focuses on the current literature about infertility issues in both females and males, specifically examining the potential treatments involving extracellular vesicles (EVs).

Understanding the intersection between placental development and cancer: Lessons from the tumor suppressor BAP1

The placenta, a pivotal organ in mammalian reproduction, allows nutrient exchange and hormonal signaling between the mother and the developing fetus. Understanding its molecular intricacies is essential for deciphering normal embryonic development and pathological conditions such as tumorigenesis. Here, we explore the multifaceted role of the tumor suppressor BRCA1-associated protein 1 (BAP1) in cancer and placentation. Initially recognized for its tumor-suppressive properties, BAP1 has emerged as a key regulator at the intersection of tumorigenesis and placental development. BAP1 influences crucial cellular processes such as cell death, proliferation, metabolism, and response to hypoxic conditions. By integrating insights from tumor and developmental biology, we illuminate the complex molecular pathways orchestrated by BAP1. This perspective highlights BAP1's significant impact on both cancer and placental development, and suggests novel therapeutic strategies that could improve outcomes for pregnancy disorders and cancer.

Lysophosphatidylcholine Impairs the Mitochondria Homeostasis Leading to Trophoblast Dysfunction in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a common pregnancy disorder associated with an increased risk of pre-eclampsia and macrosomia. Recent research has shown that the buildup of excess lipids within the placental trophoblast impairs mitochondrial function. However, the exact lipids that impact the placental trophoblast and the underlying mechanism remain unclear. GDM cases and healthy controls were recruited at Kaohsiung Medical University Hospital. The placenta and cord blood were taken during birth. Confocal and electron microscopy were utilized to examine the morphology of the placenta and mitochondria. We determined the lipid composition using liquid chromatography-mass spectrometry in data-independent analysis mode (LC/MSE). In vitro studies were carried out on choriocarcinoma cells (JEG3) to investigate the mechanism of trophoblast mitochondrial dysfunction. Results showed that the GDM placenta was distinguished by increased syncytial knots, chorangiosis, lectin-like oxidized low-density lipoprotein (LDL) receptor-1 (LOX-1) overexpression, and mitochondrial dysfunction. Lysophosphatidylcholine (LPC) 16:0 was significantly elevated in the cord blood LDL of GDM patients. In vitro, we demonstrated that LPC dose-dependently disrupts mitochondrial function by increasing reactive oxygen species (ROS) levels and HIF-1α signaling. In conclusion, highly elevated LPC in cord blood plays a pivotal role in GDM, contributing to trophoblast impairment and pregnancy complications.

Glyphosate modifies the gene expression and migration of trophoblastic cells without altering the process of angiogenesis or the implantation of blastocysts in vitro

Adverse pregnancy outcomes have been associated with the presence of glyphosate (G) in umbilical cord, serum, and urine samples from pregnant women. Our aim was to study the effect of G on blastocyst implantation using an in vitro mouse model, and the migration and acquisition of endothelial phenotype of the human trophoblastic HTR8/SVneo (H8) cells. In mouse blastocysts, no differences in attachment time and implantation outgrowth area were observed after G exposure. H8 cell migration was stimulated by 0.625 μM G without cytotoxicity. After 6 h, the mRNA expression of vascular endothelial growth factor (VEGF) and C-C motif chemokine ligand 2 (CCL2) was upregulated in H8 cells exposed to 1.25 μM G when compared vehicle-treated cells (p ≤ 0.05). No differences were observed in interleukin 11, VEGF receptor 1, and coagulation factor II thrombin receptor in H8 cells exposed to different concentrations of G for 6 h compared to the vehicle. Interestingly, exposure to G did not alter angiogenesis as measured by a tube formation assay. Taken all together, these results suggest that G exposure may contribute as a risk factor during pregnancy, due to its ability to alter trophoblast migration and gene expression.

Effect of bromodomain PHD-finger transcription factor (BPTF) on trophoblast epithelial-to-mesenchymal transition

The trophoblast epithelial-to-mesenchymal transition (EMT) is a procedure related to embryo implantation, spiral artery establishment and fetal-maternal communication, which is a key event for successful pregnancy. Inadequate EMT is one of the pathological mechanisms of recurrent miscarriage (RM). Whole-exome sequencing revealed that the mutation of bromodomain PHD-finger transcription factor (BPTF) was strongly associated with RM. In the present study, the effects of BPTF on EMT and the underlying mechanism were investigated. We found that the expression of BPTF in the villi of RM patients was significantly downregulated. Gene Ontology (GO) analysis revealed that BPTF participated in cell adhesion. The knockdown of BPTF prevented EMT and attenuated trophoblast invasion in vitro. BPTF activated Slug transcription by binding directly to the promoter region of the Slug gene. Interestingly, the protein levels of both Slug and BPTF were decreased in the villous cytotrophoblasts (VCTs) of RM villi. In conclusion, BPTF participates in the regulation of trophoblast EMT by activating Slug expression, suggesting that BPTF defects are an important factor in RM pathogenesis.

Current understanding of the pathogenesis of placenta accreta spectrum disorder with focus on mitochondrial function

AIM

The refinement of assisted reproductive technology, including the development of cryopreservation techniques (vitrification) and ovarian stimulation protocols, makes frozen embryo transfer (FET) an alternative to fresh ET and has contributed to the success of assisted reproductive technology. Compared with fresh ET cycles, FET cycles were associated with better in vitro fertilization outcomes; however, the occurrence of pregnancy-induced hypertension, preeclampsia, and placenta accreta spectrum (PAS) was higher in FET cycles. PAS has been increasing steadily in incidence as a life-threatening condition along with cesarean rates worldwide. In this review, we summarize the current understanding of the pathogenesis of PAS and discuss future research directions.

METHODS

A literature search was performed in the PubMed and Google Scholar databases.

RESULTS

Risk factors associated with PAS incidence include a primary defect of the decidua basalis or scar dehiscence, aberrant vascular remodeling, and abnormally invasive trophoblasts, or a combination thereof. Freezing, thawing, and hormone replacement manipulations have been shown to affect multiple cellular pathways, including cell proliferation, invasion, epithelial-to-mesenchymal transition (EMT), and mitochondrial function. Molecules involved in abnormal migration and EMT of extravillous trophoblast cells are beginning to be identified in PAS placentas. Many of these molecules were also found to be involved in mitochondrial biogenesis and dynamics.

CONCLUSION

The etiology of PAS may be a multifactorial genesis with intrinsic predisposition (e.g., placental abnormalities) and certain environmental factors (e.g., defective decidua) as triggers for its development. A distinctive feature of this review is its focus on the potential factors linking mitochondrial function to PAS development.

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

INTRODUCTION

Spontaneous miscarriage is a common complication of early pregnancy. Previous studies have shown that mitochondrial function plays an important role in establishment of a successful pregnancy. Cytochrome c oxidase subunit 4 isoform 1 (COX4I1), a component of electron transport chain complex Ⅳ, is required for coupling the rate of ATP production to energetic requirements. However, there is very limited research on its role in trophoblast biology and how its dysfunction may contribute to spontaneous miscarriage.

METHODS

Placental villi (7-10 weeks gestational age) collected from either induced termination of pregnancy or after spontaneous miscarriage were examined for expression of COX4I1. COX4I1 was knocked down by siRNA transfection of primary isolates of EVT cells. Real-time cell analysis (RTCA) and 5-Ethynyl-2'-deoxyuridine (EdU) were used to detect changes in proliferation ability after COX4I1 knockdown of EVT cells. Migration and invasion indices were determined by RTCA. Mitochondrial morphology was observed via MitoTracker staining. Oxidative phosphorylation, ATP production, and glycolysis in COX4I1-deficient cells and controls were assessed by a cellular energy metabolism analyzer (Seahorse).

RESULTS

In placental villous tissue, COX4I1 expression was significantly decreased in the spontaneous miscarriage group. Knockdown of COX4I1 inhibited EVT cell proliferation, increased the migration and invasion ability and mitochondrial fusion of EVT cells. Mitochondrial respiration and glycolysis were impaired in COX4I1-deficient EVT cells. Knockdown of MMP1 could rescue the increased migration and invasion induced by COX4I1 silencing.

DISCUSSION

Low expression of COX4I1 leads to mitochondrial dysfunction in EVT, resulting in altered trophoblast function, and ultimately to pregnancy loss.

MicroRNA‑155‑5p inhibits trophoblast cell proliferation and invasion by disrupting centrosomal function

Recurrent miscarriage is used to refer to more than three pregnancy failures before 20 weeks of gestation. Defective trophoblast cell growth and invasion are frequently observed in recurrent miscarriage. Several microRNAs (miRs), including miR‑155‑5p, are aberrantly upregulated in recurrent miscarriage; however, the underlying molecular mechanisms remain unclear. The centrosome orchestrates microtubule networks and coordinates cell cycle progression. In addition, it is a base for primary cilia, which are antenna‑like organelles that coordinate signaling during development and growth. Thus, deficiencies in centrosomal functions can lead to several disease, such as breast cancer and microcephaly. In the present study, the signaling cascades were analyzed by western blotting, and the centrosome and primary cilia were observed and analyzed by immunofluorescence staining. The results showed that overexpression of miR‑155‑5p induced centrosome amplification and blocked primary cilia formation in trophoblast cells. Notably, centrosome amplification inhibited trophoblast cell growth by upregulating apoptotic cleaved‑caspase 3 and cleaved‑poly (ADP‑ribose) polymerase in miR‑155‑5p‑overexpressing trophoblast cells. In addition, overexpression of miR‑155‑5p inhibited primary cilia formation, thereby inhibiting epithelial‑mesenchymal transition and trophoblast cell invasion. All phenotypes could be rescued when cells were co‑transfected with the miR‑155‑5p inhibitor, thus supporting the role of miR‑155‑5p in centrosomal functions. It was also found that miR‑155‑5p activated autophagy, whereas disruption of autophagy via the depletion of autophagy‑related 16‑like 1 alleviated miR‑155‑5p‑induced apoptosis and restored trophoblast cell invasion. In conclusion, the present study indicated a novel role of miR‑55‑5p in mediating centrosomal function in recurrent miscarriage.

Placenta: an old organ with new functions

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

Xenobiotic metabolites modify immune responses of the cervicovaginal epithelium: potential mechanisms underlying barrier disruption

OBJECTIVE

Xenobiotic metabolites are exogenous biochemicals that can adversely impact reproductive health. We previously identified xenobiotics in cervicovaginal fluid during pregnancy in association with short cervix. In other organ systems, xenobiotics can modify epithelial barrier function. We hypothesise that xenobiotics dysregulate epithelial cell and macrophage immune responses as a mechanism to disrupt the cervicovaginal barrier.

DESIGN

In vitro cell culture system.

SETTING

Laboratory within academic institution.

SAMPLE

Vaginal, ectocervical and endocervical epithelial cell lines and primary macrophages.

METHODS

Cells were treated with diethanolamine (2.5 mM), ethyl glucoside (5 mM) or tartrate (2.5 mM) for 24 h.

MAIN OUTCOME MEASURES

Cytokines and matrix metalloproteinases were measured in cell supernatants (n = 3 per condition). One-way analysis of variance (ANOVA) with Dunnett's test for multiple comparisons was performed.

RESULTS

Diethanolamine induces inflammatory cytokines, whereas ethyl glucoside and tartrate generally exert anti-inflammatory effects across all cells. Diethanolamine increases interleukin 6 (IL-6), IL-8, interferon γ-induced protein 10 kDa (IP-10), growth-regulated oncogene (GRO), fractalkine, matrix metalloproteinase 1 (MMP-1), MMP-9 and MMP-10 (p < 0.05 for all), factors involved in acute inflammation and recruitment of monocytes, neutrophils and lymphocytes. Ethyl glucoside and tartrate decrease multiple cytokines, including RANTES and MCP-1 (p < 0.05 for all), which serve as chemotactic factors. Vaginal cells exhibit heightened inflammatory tone compared with cervical cells and macrophages, with a greater number of differentially expressed analytes after xenobiotic exposure.

CONCLUSIONS

Xenobiotic metabolites present in the cervicovaginal space during pregnancy modify immune responses, unveiling potential pathways through which environmental exposures may contribute to the pathogenesis of cervical remodelling preceding preterm birth. Future work identifying xenobiotic sources and routes of exposure offers the potential to modify environmental risks to improve pregnancy outcomes.

Inhibition of the endoplasmic reticulum stress-associated IRE-1 pathway alleviates preterm birth

BACKGROUND

Premature birth (PTB) remains a major global health concern due to its association with neonatal morbidity and mortality. The unfolded protein response (UPR) within the endoplasmic reticulum (ER) is tightly regulated by Inositol-requiring enzyme type 1 (IRE-1), a pivotal cellular modulator. This study seeks to elucidate the role of the ER stress (ERS)-related IRE-1 pathway in PTB.

METHODS

Human placental trophoblast cells HTR8/Svneo were exposed to the ER-stress inducer tunicamycin (TM). The expression of IRE-1 and ERS-associated proteins ATF6, GRP78, and XBP-1 was assessed in placental tissues and TM-treated cells. Cellular viability, migration, invasion, and apoptosis were evaluated through a series of experimental assays. Additionally, various methods were employed to assess and verify the activation of autophagy, using the autophagy marker, microtubule-associated protein 1A/1B-light chain 3 (LC3). Additionally, TUDCA (an ERS inhibitor) was used to assess its potential to counteract the TM-induced cell effects.

RESULTS

Elevated levels of ATF6, GRP78, and XBP-1 were observed in PTB tissues and cells. TM treatment substantially reduced cell viability, migration, and invasion while promoting apoptosis. Treatment with TUDCA (an ERS inhibitor) counteracted the effects of TM on the cells. Furthermore, we identified an overexpression of IRE-1 in PTB tissues and cells and its knockdown enhanced cell viability, migration, and invasion while suppressed apoptosis and autophagy under TM stimulation. Notably, IRE-1 was found to modulate the activity of the IRE-1/XBP1/CHOP signaling pathway in TM-treated cells.

CONCLUSION

The upregulation of IRE-1 in PTB placental tissues is implicated in the pathogenesis of PTB. Importantly, inhibiting the ERS-associated IRE-1/XBP1/CHOP pathway may be a good strategy in mitigating PTB.

Upregulation of miR-20b-5p inhibits trophoblast invasion by blocking autophagy in recurrent miscarriage

Recurrent miscarriage is defined as more than three pregnancy failures occurring before 20 weeks of gestation. Poor differentiation of the endometrial stroma or defective trophoblast cell invasion at the maternal-fetal interface leads to recurrent miscarriages. Several miRNAs, including miR-20b-5p, are aberrantly regulated in recurrent miscarriages; however, the underlying molecular mechanisms remain unclear. Primary cilia are antenna-like organelles that coordinate signaling during development and differentiation. Defective primary cilia formation leads to complications, such as recurrent miscarriage or preeclampsia. Here, we demonstrated that miR-20b-5p inhibited trophoblast cell invasion by blocking primary cilia formation. Mechanistically, miR-20b-5p targeted and inhibited ATG16L1 and ATG7 expression, thereby blocking autophagy. Defective autophagy reduced primary cilia formation and stopped ERK activation, which is a crucial signaling pathway for trophoblast invasion. Aspirin is used to prevent recurrent miscarriages in clinical settings. Treatment with aspirin inhibited miR-20b-5p levels, thus restoring primary cilia formation and trophoblast invasion. Thus, our findings uncovered the molecular mechanism by which miR-20b-5p suppressed primary cilia formation and trophoblast invasion by reducing the expression of ATG16L1 and ATG7. Moreover, we found that the defective phenotypes could be rescued by aspirin in recurrent miscarriages.

Physiological and pathological evidence of O-GlcNAcylation regulation during pregnancy related process

O-GlcNAcylation is a dynamic and reversible post-translational modification (PTM) controlled by the enzymes O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Changes in its expression lead to a breakdown in cellular homeostasis, which is linked to several pathological processes. Placentation and embryonic development are periods of high cell activity, and imbalances in cell signaling pathways can result in infertility, miscarriage, or pregnancy complications. O-GlcNAcylation is involved in cellular processes such as genome maintenance, epigenetic regulation, protein synthesis/degradation, metabolic pathways, signaling pathways, apoptosis, and stress response. Trophoblastic differentiation/invasion and placental vasculogenesis, as well as zygote viability and embryonic neuronal development, are all dependent on O-GlcNAcylation. This PTM is required for pluripotency, which is a required condition for embryonic development. Further, this pathway is a nutritional sensor and cell stress marker, which is primarily measured by the OGT enzyme and its product, protein O-GlcNAcylation. Yet, this post-translational modification is enrolled in metabolic and cardiovascular adaptations during pregnancy. Finally, evidence of how O-GlcNAc impacts pregnancy during pathological conditions such as hyperglycemia, gestational diabetes, hypertension, and stress disorders are reviewed. Considering this scenario, progress in understanding the role of O- GlcNAcylation in pregnancy is required.

Mono(2-ethylhexyl) phthalate induces transcriptomic changes in placental cells based on concentration, fetal sex, and trophoblast cell type

Phthalates are ubiquitous plasticizer chemicals found in consumer products. Exposure to phthalates during pregnancy has been associated with adverse pregnancy and birth outcomes and differences in placental gene expression in human studies. The objective of this research was to evaluate global changes in placental gene expression via RNA sequencing in two placental cell models following exposure to the phthalate metabolite mono(2-ethylhexyl) phthalate (MEHP). HTR-8/SVneo and primary syncytiotrophoblast cells were exposed to three concentrations (1, 90, 180 µM) of MEHP for 24 h with DMSO (0.1%) as a vehicle control. mRNA and lncRNAs were quantified using paired-end RNA sequencing, followed by identification of differentially expressed genes (DEGs), significant KEGG pathways, and enriched transcription factors (TFs). MEHP caused gene expression changes across all concentrations for HTR-8/SVneo and primary syncytiotrophoblast cells. Sex-stratified analysis of primary cells identified different patterns of sensitivity in response to MEHP dose by sex, with male placentas being more responsive to MEHP exposure. Pathway analysis identified 11 KEGG pathways significantly associated with at least one concentration in both cell types. Four ligand-inducible nuclear hormone TFs (PPARG, PPARD, ESR1, AR) were enriched in at least three treatment groups. Overall, we demonstrated that MEHP differentially affects placental gene expression based on concentration, fetal sex, and trophoblast cell type. This study confirms prior studies, as enrichment of nuclear hormone receptor TFs were concordant with previously published mechanisms of phthalate disruption, and generates new hypotheses, as we identified many pathways and genes not previously linked to phthalate exposure.

Hyperin promotes proliferation, migration, and invasion of HTR-8/SVneo trophoblast cells via activation of JAK1/STAT3 pathway in recurrent spontaneous abortions

The proliferation of extravillous trophoblasts (EVT) and their further migration, invasion, and differentiation into the decidual and myometrial vasculature are vital for spiral artery remodeling. These physiological functions of EVT are also essential steps in the implantation of the human embryo and the formation of the placenta and are closely related to pregnancy maintenance and the occurrence of abortion. Hyperin is a flavonoid with anti-inflammatory, pro-proliferative, and anti-apoptotic properties. Consequently, we investigated the previously unexplored effects of hyperin on the proliferation, migration, and invasion of HTR-8/SVneo cells. Human extravillous trophoblast-derived HTR-8/SVneo cells were incubated with different concentrations of hyperin (0, 5, 10, 25, 50, and 100 μM) to observe the changes in cell proliferation, migration, invasive capacity, and pathway activation. Proliferation, migration, and invasion were promoted by activating the JAK1/STAT3 pathway in HTR-8/SVneo cells treated with hyperin. In addition, brepocitinib (PF-06700841) significantly inhibited the proliferation, migration, and invasion effects of hyperin on HTR-8/SVneo cells. In vivo experiments confirmed that hyperin reduces the embryo loss rate in recurrent spontaneous abortion (RSA) model mice. Furthermore, our study revealed that hyperin promoted the proliferation, migration, and invasion of HTR-8/SVneo cells via activation of the JAK1/STAT3 pathway, further improving pregnancy outcomes in RSA.

Environmental toxicants and placental function

The placenta is a temporary endocrine organ that facilitates gas, nutrient, and waste exchange between maternal and fetal compartments, partially shielding the fetus from potentially hazardous environmental toxicants. However, rather than being "opaque", the placenta is translucent or even transparent to some potential fetal developmental hazards, including toxic trace elements (TEs), perfluoroalkyl and polyfluoroalkyl substances (PFAS), and environmental phenols (EPs) to which women with pregnancy are frequently exposed. These agents are both passively and actively transferred to the fetal compartment, where endocrine disruption, oxidative stress, and epigenetic changes may occur. These pathologies may directly impact the fetus or deposit and accumulate in the placenta to indirectly impact fetal development. Thus, it is critical for clinicians to understand the potential placental toxicity and transfer of widely distributed environmental agents ubiquitous during pregnancy. With such knowledge, targeted interventions and clinical recommendations can be developed to limit those risks.

Adverse events of recreational cannabis use during pregnancy reported to the French Addictovigilance Network between 2011 and 2020

Cannabis is the main illicit psychoactive substance used by pregnant women in France. The aim of the present national survey was to describe adverse events (AEs) of recreational cannabis use during pregnancy reported to the French Addictovigilance Network (FAN). Spontaneous reports (SRs) of AEs related to recreational cannabis use during pregnancy were collected by the FAN between 01/01/2011 and 31/01/2021 (excluding cannabidiol and synthetic cannabinoids). Over the study period, 160 SRs involved cannabis use alone or in association with tobacco (59% of all SRs) which increased. Among the 175 maternal AEs, the most commons were psychiatric AEs experienced by 96 (64.9%) women, in particular cannabis use disorders (n = 89, 60.1%), dependence (n = 54, 36.5%) and abuse (n = 21, 14.2%). Among the 57 fetal AEs, the most common were heart rhythm disorders that affected 25 (16.9%) fetuses and intrauterine growth restriction (IUGR) (n = 20, 13.5%). Among the 140 neonatal AEs, the most common were IUGR experienced by 39 (26.3%) newborns and prematurity (n = 32, 21.6%). Twelve cases of congenital malformations were observed and 4 intrauterine/neonatal deaths. Furthermore, some of these AEs (n = 13) were unexpected. Cannabis use during pregnancy has problematic consequences for both mothers and infants who need close monitoring.

Fluroxypyr-1-methylheptyl ester induced ROS production and mitochondrial apoptosis through the MAPK signaling cascade in porcine trophectoderm and uterine luminal epithelial cells

FPMH (Fluroxypyr-1-methylheptyl ester) is a synthetic auxin herbicide used in agriculture. The mechanism by which FPMH induces adverse effects in porcine trophectoderm (pTr) and porcine uterine luminal epithelial (pLE) cells, which are involved in porcine implantation, have not been studied yet. Therefore, the present study investigates the toxicological effects of FPMH on pTr and pLE cells. We confirmed that FPMH induced cytotoxic effects on the cells, including apoptosis induction, mitochondrial membrane potential (MMP) depolarization, and ROS production. The phosphorylation of the MAPK pathway (ERK1/2, JNK, and p38) was dysregulated by FPMH administration. In addition, FPMH could suppress cell-cell adhesion and migration abilities of pTr and pLE, which are crucial for implantation. Therefore, exposure to FPMH induced adverse effects in pTr and pLE cells and could result in implantation failure.

Effects of KCa channels on biological behavior of trophoblasts

The Ca²⁺-activated potassium (KCa) channels are involved in many cellular functions, but their roles in trophoblasts are unclear. This study aimed to clarify the effects of KCa channels on the biological behavior of trophoblasts. The localization and expression of the three types of KCa channels, including large-conductance KCa channels (BKCa), intermediate-conductance KCa channels (IKCa), and small-conductance KCa channels (SKCa), were detected in human chorionic villi taken from pregnant women between 5 and 8 weeks of gestation (n = 15) and HTR-8/SVneo cells. The effects of KCa channels on proliferation, apoptosis, and migration of HTR-8/SVneo cells were examined by using the activators or inhibitors of KCa channels. Results showed that KCa channels were mainly localized on the membrane and in the cytoplasm of trophoblasts in human chorionic villi and HTR-8/SVneo cells. The proliferation and migration of HTR-8/SVneo cells were inhibited by activating KCa channels. Apoptosis of trophoblasts was promoted through activating BKCa channels but was not affected by neither activating nor inhibiting IKCa and SKCa channels. This study substantiated the abovementioned biological roles of KCa channels in trophoblast cells, which is fundamental to further research on whether dysfunction of KCa channels is involved in the pathogenesis of pregnancy-related complications.

The implications of exosomes in pregnancy: emerging as new diagnostic markers and therapeutics targets

Extracellular vehicles (EVs) are a heterogeneous group of cell and membranous particles originating from different cell compartments. EVs participate in many essential physiological functions and mediate fetal-maternal communications. Exosomes are the smallest unit of EVs, which are delivered to the extracellular space. Exosomes can be released by the umbilical cord, placenta, amniotic fluid, and amniotic membranes and are involved in angiogenesis, endothelial cell migration, and embryo implantation. Also, various diseases such as gestational hypertension, gestational diabetes mellitus (GDM), preterm birth, and fetal growth restriction can be related to the content of placental exosomes during pregnancy. Due to exosomes' ability to transport signaling molecules and their effect on sperm function, they can also play a role in male and female infertility. In the new insight, exosomal miRNA can diagnose and treat infertilities disorders. In this review, we focused on the functions of exosomes during pregnancy. Video abstract.