Placental trophoblast cell differentiation: Physiological regulation and pathological relevance to preeclampsia

miR-31-5p from placental and peripheral blood exosomes is a potential biomarker to diagnose preeclampsia

Background

Preeclampsia, a multisystem disorder of unknown etiology, is one of the leading causes of maternal and perinatal morbidity and mortality. Identifying sensitive, noninvasive markers can aid its prevention and improve prognosis. microRNAs (miRs), which function as negative regulators of gene expression, are closely related to preeclampsia occurrence and development. Herein we investigated the relationship between the DLK1-Dio3 imprinted miR cluster derived from placental and peripheral blood exosomes of pregnant women with preeclampsia and routine clinical diagnostic indicators, and also determined its potential as a noninvasive diagnostic marker.

Methods

Exosomes were extracted from the placenta and peripheral blood of pregnant women with preeclampsia.

Results

qPCR data indicated that the expression level of miRs, such as miR-134, miR-31-5p, miR-655, miR-412, miR-539, miR-409, and miR-496, in pregnant women with preeclampsia was significantly lower than that in healthy controls; miR-31-5p expression was the most different. Gene ontology analysis predicted that genes negatively regulated by miR-31-5p were mainly enriched in cellular entity, cellular process, and binding; moreover, Kyoto Encyclopedia of Genes and Genomes pathway analyses indicated that genes were involved in gonadotropin-releasing hormone receptor pathway and other signaling pathways. Correlation analysis revealed that miR-31-5p was significantly negatively correlated with clinical indicators of preeclampsia, such as systolic and diastolic pressure, lactate dehydrogenase, and proteinuria.

Conclusion

We believe that exosome-derived miR-31-5p can serve as an effective and sensitive biomarker to determine the course of preeclampsia in pregnant women.

The effects of aspartame on the HTR8/SVneo extravillous trophoblast cell line

Extravillous trophoblasts (EVTs) are a key cell type involved in placentation. Aspartame is an artificial sweetener with a widespread use. In rodents, aspartame ingestion during pregnancy was found to cause a reduction in placental and fetal weights, but its effect in placentation at a cellular level has not been studied. Aspartame is completely hydrolyzed in the gastrointestinal tract into L-phenylalanine, L-aspartic acid, and methanol. We aimed to study the effects of aspartame and its metabolites on placentation related characteristics of EVTs. For this, we exposed HTR-8/SVneo cells to aspartame (0.001, 0.01, 0.1, 0.5 and 1 mM), L-phenylalanine (0.14 and 0.5 mM), L-aspartic acid (0.82, 2.8 and 10 mM) or methanol (0.14 and 0.8 mM) for 24 h. Aspartame had an anti-proliferative effect, decreased the number of metabolically active cells and glucose cellular uptake and increased the number of cells arrested in S phase. L-aspartic acid significantly reduced glucose uptake and whole-cell protein content. L-phenylalanine had an anti-proliferative effect and increased the number of metabolically active cells. Interestingly, methanol exerted very marked effects on HTR8/SVneo cells: it showed an anti-proliferative effect, decreased glucose uptake, the migratory ability and the number of cells in the G2/M phase and increased oxidative stress levels, in concentrations corresponding to the blood levels after the 99th percentile of projected daily ingestion of aspartame. Overall, our results demonstrate that aspartame and its metabolites can affect several characteristics of EVTs and support the conclusion that the effect of aspartame in the placenta should be further evaluated.

Regulatory roles of non-coding RNAs and m6A modification in trophoblast functions and the occurrence of its related adverse pregnancy outcomes

Adverse pregnancy outcomes, such as preeclampsia, gestational diabetes mellitus, fetal growth restriction, and recurrent miscarriage, occur frequently in pregnant women and might further induce morbidity and mortality for both mother and fetus. Increasing studies have shown that dysfunctions of human trophoblast are related to these adverse pregnancy outcomes. Recent studies also showed that environmental toxicants could induce trophoblast dysfunctions. Moreover, non-coding RNAs (ncRNAs) have been reported to play important regulatory roles in various cellular processes. However, the roles of ncRNAs in the regulation of trophoblast dysfunctions and the occurrence of adverse pregnancy outcomes still need to be further investigated, especially with exposure to environmental toxicants. In this review, we analyzed the regulatory mechanisms of ncRNAs and m6A methylation modification in the dysfunctions of trophoblast cells and the occurrence of adverse pregnancy outcomes and also summarized the harmful effects of environmental toxicants. In addition to DNA replication, mRNA transcription, and protein translation, ncRNAs and m6A modification might be considered as the fourth and fifth elements that regulate the genetic central dogma, respectively. Environmental toxicants might also affect these processes. In this review, we expect to provide a deeper scientific understanding of the occurrence of adverse pregnancy outcomes and to discover potential biomarkers for the diagnosis and treatment of these outcomes.

Palmitic Acid Impedes Extravillous Trophoblast Activity by Increasing MRP1 Expression and Function

Normal function of placental extravillous trophoblasts (EVTs), which are responsible for uteroplacental vascular remodeling, is critical for adequate delivery of oxygen and nutrients to the developing fetus and normal fetal programming. Proliferation and invasion of spiral arteries by EVTs depends upon adequate levels of folate. Multidrug resistance-associated protein 1 (MRP1), which is an efflux transporter, is known to remove folate from these cells. We hypothesized that palmitic acid increases MRP1-mediated folate removal from EVTs, thereby interfering with EVTs' role in early placental vascular remodeling. HTR-8/SVneo and Swan-71 cells, first trimester human EVTs, were grown in the absence or presence of 0.5 mM and 0.7 mM palmitic acid, respectively, for 72 h. Palmitic acid increased ABCC1 gene expression and MRP1 protein expression in both cell lines. The rate of folate efflux from the cells into the media increased with a decrease in migration and invasion functions in the cultured cells. Treatment with N-acetylcysteine (NAC) prevented the palmitic acid-mediated upregulation of MRP1 and restored invasion and migration in the EVTs. Finally, in an ABCC1 knockout subline of Swan-71 cells, there was a significant increase in invasion and migration functions. The novel finding in this study that palmitic acid increases MRP1-mediated folate efflux provides a missing link that helps to explain how maternal consumption of saturated fatty acids compromises the in utero environment.

Single-Cell Transcriptomics of Proliferative Phase Endometrium: Systems Analysis of Cell–Cell Communication Network Using CellChat

The endometrium thickness increases by which endometrial angiogenesis occurs in parallel with the rapid growth of endometrium during the proliferative phase, which is orchestrated by complex cell–cell interactions and cytokine networks. However, the intercellular communication has not been fully delineated. In the present work, we studied the cell–cell interactome among cells of human proliferative phase endometrium using single-cell transcriptomics. The transcriptomes of 33,240 primary endometrial cells were profiled at single-cell resolution. CellChat was used to infer the cell–cell interactome by assessing the gene expression of receptor–ligand pairs across cell types. In total, nine cell types and 88 functionally related signaling pathways were found. Among them, growth factors and angiogenic factor signaling pathways, including EGF, FGF, IGF, PDGF, TGFb, VEGF, ANGPT, and ANGPTL that are highly associated with endometrial growth, were further analyzed and verified. The results showed that stromal cells and proliferating stromal cells represented cell–cell interaction hubs with a large number of EGF, PDGF incoming signals, and FGF outgoing signals. Endothelial cells exhibited cell–cell interaction hubs with a plenty of VEGF, TGFb incoming signals, and ANGPT outgoing signals. Unciliated epithelial cells, ciliated epithelial cells, and macrophages exhibited cell–cell interaction hubs with substantial EGF outgoing signals. Ciliated epithelial cells represented cell–cell interaction hubs with a large number of IGF and TGFb incoming signals. Smooth muscle cells represented lots of PDGF incoming signals and ANGPT and ANGPTL outgoing signals. This study deconvoluted complex intercellular communications at the single-cell level and predicted meaningful biological discoveries, which deepened the understanding of communications among endometrial cells.

How trophoblasts fuse: an in-depth look into placental syncytiotrophoblast formation

In humans, cell fusion is restricted to only a few cell types under normal conditions. In the placenta, cell fusion is a critical process for generating syncytiotrophoblast: the giant multinucleated trophoblast lineage containing billions of nuclei within an interconnected cytoplasm that forms the primary interface separating maternal blood from fetal tissue. The unique morphology of syncytiotrophoblast ensures that nutrients and gases can be efficiently transferred between maternal and fetal tissue while simultaneously restricting entry of potentially damaging substances and maternal immune cells through intercellular junctions. To maintain integrity of the syncytiotrophoblast layer, underlying cytotrophoblast progenitor cells terminate their capability for self-renewal, upregulate expression of genes needed for differentiation, and then fuse into the overlying syncytium. These processes are disrupted in a variety of obstetric complications, underscoring the importance of proper syncytiotrophoblast formation for pregnancy health. Herein, an overview of key mechanisms underlying human trophoblast fusion and syncytiotrophoblast development is discussed.

Study of association between different microRNA variants and the risk of idiopathic recurrent pregnancy loss

AIM

Recurrent pregnancy loss (RPL) is a common reproductive disorder among women and a major cause of infertility among them; however, the underlying causes of RPL remain unknown which have led to great difficulties and complications in the treatment. MicroRNAs (miRNA) have been shown to be a potential diagnosis tools in different reproductive disorders. This study aimed to investigate the association of four different miRNA variants with the risk of idiopathic RPL (iRPL).

METHODS

A total of 450 women including 225 patients and 225 controls were recruited in this study. DNA was extracted, and genotyped by PCR method. Haplotype analysis, as well as linkage disequilibrium between SNPs, was performed.

CONCLUSION

This study suggested that rs4636297, rs41291957, and rs353292, but not rs531564 can play a risk factor role for iRLP.

Single-cell transcriptional profiling reveals cellular and molecular divergence in human maternal-fetal interface

Placenta plays essential role in successful pregnancy, as the most important organ connecting and interplaying between mother and fetus. However, the cellular characteristics and molecular interaction of cell populations within the fetomaternal interface is still poorly understood. Here, we surveyed the single-cell transcriptomic landscape of human full-term placenta and revealed the heterogeneity of cytotrophoblast cell (CTB) and stromal cell (STR) with the fetal/maternal origin consecutively localized from fetal section (FS), middle section (Mid_S) to maternal section (Mat_S) of maternal–fetal interface. Then, we highlighted a subpopulation of CTB, named trophoblast progenitor-like cells (TPLCs) existed in the full-term placenta and mainly distributed in Mid_S, with high expression of a pool of putative cell surface markers. Further, we revealed the putative key transcription factor PRDM6 that might promote the differentiation of endovascular extravillous trophoblast cells (enEVT) by inhibiting cell proliferation, and down-regulation of PRDM6 might lead to an abnormal enEVT differentiation process in PE. Together, our study offers important resources for better understanding of human placenta and stem cell-based therapy, and provides new insights on the study of tissue heterogeneity, the clinical prevention and control of PE as well as the maternal–fetal interface.

The role of insulin-like growth factor 2 mRNA binding proteins in female reproductive pathophysiology

Insulin-like growth factor 2 (IGF2) mRNA binding proteins (IMPs) family belongs to a highly conserved family of RNA-binding proteins (RBPs) and is responsible for regulating RNA processing including localization, translation and stability. Mammalian IMPs (IMP1-3) take part in development, metabolism and tumorigenesis, where they are believed to play a major role in cell growth, metabolism, migration and invasion. IMPs have been identified that are expressed in ovary, placenta and embryo. The up-to-date evidence suggest that IMPs are involved in folliculogenesis, oocyte maturation, embryogenesis, implantation, and placentation. The dysregulation of IMPs not only contributes to carcinogenesis but also disturbs the female reproduction, and may participate in the pathogenesis of reproductive diseases and obstetric syndromes, such as polycystic ovary syndrome (PCOS), pre-eclampsia (PE), gestational diabetes mellitus (GDM) and gynecological tumors. In this review, we summarize the role of IMPs in female reproductive pathophysiology, and hope to provide new insights into the identification of potential therapeutic targets.

Primary Human Trophoblasts Mimic the Preeclampsia Phenotype after Acute Hypoxia-Reoxygenation Insult

Preeclampsia (PE) is a pregnancy-specific disorder that affects 3 to 5% of pregnancies worldwide and is one of the leading causes of maternal and fetal morbidity and mortality. Nevertheless, how these events occur remains unclear. We hypothesized that the induction of hypoxic conditions in vitro in primary human trophoblast cells would mimic several characteristics of PE found in vivo. We applied and characterized a model of primary cytotrophoblasts isolated from healthy pregnancies that were placed under different oxygen concentrations: ambient O₂ (5% pCO₂, 21%pO₂, 24 h, termed “normoxia”), low O₂ concentration (5% pCO₂, 1.5% pO₂, 24 h, termed “hypoxia”), or “hypoxia/reoxygenation” (H/R: 6 h intervals of normoxia and hypoxia for 24 h). Various established preeclamptic markers were assessed in this cell model and compared to placental tissues obtained from PE pregnancies. Seventeen PE markers were analyzed by qPCR, and the protein secretion of soluble fms-like tyrosine kinase 1 (sFlT-1) and the placenta growth factor (PlGF) was determined by ELISA. Thirteen of seventeen genes associated with angiogenesis, the renin–angiotensin system, oxidative stress, endoplasmic reticulum stress, and the inflammasome complex were susceptible to H/R and hypoxia, mimicking the expression pattern of PE tissue. In cell culture supernatants, the secretion of sFlT-1 was increased in hypoxia, while PlGF release was significantly reduced in H/R and hypoxia. In the supernatants of our cell models, the sFlT-1/PlGF ratio in hypoxia and H/R was higher than 38, which is a strong indicator for PE in clinical practice. These results suggest that our cellular models reflect important pathological processes occurring in PE and are therefore suitable as PE in vitro models.

Phosphoglycerate mutase 5 promotes necroptosis in trophoblast cells through activation of dynamin-related protein 1 in early-onset preeclampsia

OBJECTIVES

Placentae from patients with preeclampsia have increased susceptibility to necroptosis and phosphoglycerate mutase 5 (PGAM5) plays a role in many necrosis pathways. We determined whether PGAM5 promotes necroptosis of trophoblast cells and the underlying mechanisms in this study.

METHODS

The injury model was established by treating JEG3 cells with hypoxia for 24 h. The functional measurements were assessed by the cell counting kit-8, propidium iodide (PI)/Annexin V staining, JC-1 staining and firefly luciferase ATP assay. The expression of proteins in human placentae and JEG3 cells was measured Western blot. PGAM5 was knocked down to study its role in hypoxia-induced necroptosis.

RESULTS

The placentae from patients with preeclampsia showed up-regulation of PGAM5 and decreased levels of p-Drp1-S637, accompanied by increased necroptosis-relevant proteins expression. The expression of PGAM5 in JEG3 cells was up-regulated under hypoxia, which promoted dephosphorylation of Drp1 at Serine 637 residue, mitochondrial dysfunction (elevated ROS level and reduced mitochondrial membrane potential and ATP content) and cellular necroptosis (increased PI⁺ /Annexin V⁺ cells and decreased cell viability), accompanied by increased expression of necroptosis-relevant proteins; knockdown of PGAM5 attenuated these phenomena.

CONCLUSIONS

Our results indicate that PGAM5 can promote necroptosis in trophoblast cells through, at least in part, activation of Drp1. It may be used as a new therapeutic target to prevent trophoblast dysfunction in preeclampsia.

Trophoblast Cell Subtypes and Dysfunction in the Placenta of Individuals with Preeclampsia Revealed by Single‑Cell RNA Sequencing

Trophoblasts, important functional cells in the placenta, play a critical role in maintaining placental function. The heterogeneity of trophoblasts has been reported, but little is known about the trophoblast subtypes and distinctive functions during preeclampsia (PE). In this study, we aimed to gain insight into the cell type-specific transcriptomic changes by performing unbiased single-cell RNA sequencing (scRNA-seq) of placental tissue samples, including those of patients diagnosed with PE and matched healthy controls. A total of 29,006 cells were identified in 11 cell types, including trophoblasts and immune cells, and the functions of the trophoblast subtypes in the PE group and the control group were also analyzed. As an important trophoblast subtype, extravillous trophoblasts (EVTs) were further divided into 4 subgroups, and their functions were preliminarily analyzed. We found that some biological processes related to pregnancy, hormone secretion and immunity changed in the PE group. We also identified and analyzed the regulatory network of transcription factors (TFs) identified in the EVTs, among which 3 modules were decreased in the PE group. Then, through in vitro cell experiments, we found that in one of the modules, CEBPB and GTF2B may be involved in EVT dysfunction in PE. In conclusion, our study showed the different transcriptional profiles and regulatory modules in trophoblasts between placentas in the control and PE groups at the single-cell level; these changes may be involved in the pathological process of PE, providing a new molecular theoretical basis for preeclamptic trophoblast dysfunction.

The disruption of human trophoblast functions by autophagy activation through PI3K/AKT/mTOR pathway induced by exposure to titanium carbide (Ti3C2) MXene

Ti₃C₂ MXene, as a novel nanomaterial, has attracted great attention due to its promising properties in biomedical applications. However, the potential effects of Ti₃C₂ MXene on trophoblast functions have not been investigated. Here, we found that Ti₃C₂ MXene exposure weakened the extension ability of villus explants in vitro. We employed human trophoblast HTR-8/SVneo cells to reveal the underlying molecular mechanisms by which Ti₃C₂ MXene exposure affected trophoblast functions. Results showed that Ti₃C₂ MXene entered cells and mostly deposited in the cytoplasm, inhibiting cell migration and invasion abilities. Furthermore, we found that Ti₃C₂ MXene exposure elevated autophagy through the inhibition of the PI3K/AKT/mTOR pathway. Meanwhile, the application of an autophagy inhibitor (3-MA) prevented autophagy and restored cell viability, resulting in the recovery of cell migration and invasion abilities. These indicated that the cellular dysfunction induced by Ti₃C₂ MXene may be mediated by autophagy activation. Our results indicated that autophagy is a key factor in eliciting HTR-8/SVneo dysfunction after Ti₃C₂ MXene exposure, which could therefore damage placental development. Autophagy inhibition is a potential therapeutic strategy for alleviating the placental toxicity of nanoparticles.

The mystery of the life tree: the placenta

The placenta is the interface between the fetal and maternal environments during mammalian gestation, critically safeguarding the health of the developing fetus and the mother. Placental trophoblasts origin from embryonic trophectoderm that differentiates into various trophoblastic subtypes through villous and extravillous pathways. The trophoblasts actively interact with multiple decidual cells and immune cells at the maternal-fetal interface and thus construct fundamental functional units, which are responsible for blood perfusion, maternal-fetal material exchange, placental endocrine, immune tolerance, and adequate defense barrier against pathogen infection. Various pregnant complications are tightly associated with the defects in placental development and function maintenance. In this review, we summarize the current views and our recent progress on the mechanisms underlying the formation of placental functional units, the interactions among trophoblasts and various uterine cells, as well as the placental barrier against pathogen infections during pregnancy. The involvement of placental dysregulation in adverse pregnancy outcomes is discussed.

Stanniocalcin2 inhibits the epithelial-mesenchymal transition and invasion of trophoblasts via activation of autophagy under high-glucose conditions

Maternal pregnancy hyperglycemia is often accompanied by placental dysfunction. During placental development, epithelial-mesenchymal transition (EMT) contributes to the transformation of relatively noninvasive trophoblasts into highly invasive extravillous trophoblasts (EVTs). However, the specific role of EMT in placentas under hyperglycemia environments remains relatively unexplored. Stanniocalcin2 (STC2) regulates EMT in many cancers. In this study, we first demonstrated that STC2 expression was upregulated in GDM placenta. We found that STC2 activated autophagy and suppressed EMT in high-glucose-treated EVTs and was associated with a lack of invasiveness. Specifically, STC2 inhibited the interactions between p62/SQSTM1 (p62) and EMT transcription factors to promote the degradation of Twist1 and Snail via a proteasome-dependent pathway. Furthermore, the PI3K/AKT/AMPK signaling pathway was involved in the regulation of autophagy and EMT by STC2. Taken together, our results reveal that STC2 may serve as a potential prognostic biomarker in GDM and sheds light on the regulatory mechanisms of trophoblast invasion.

microRNA-140-5p from human umbilical cord mesenchymal stem cells-released exosomes suppresses preeclampsia development

This work unraveled the action of human umbilical cord mesenchymal stem cells-released exosomes (huc-MSCs-EXO) transfer of miR-140-5p in preeclampsia (PE). miR-140-5p and follistatin-like 3 (FSTL3) expression in placental tissues of PE patients was tested. EXO were isolated from huc-MSCs. Hypoxic trophoblast cells were co-cultured with huc-MSCs-EXO. Cell biological functions, angiogenesis, and inflammation were evaluated. Suppressed miR-140-5p and induced FSTL3 levels were measured in PE. Huc-MSCs-EXO drove biological functions and angiogenesis while hindering inflammation in hypoxic trophoblast cells. Increasing miR-140-5p further improved the positive role of huc-MSCs-EXO for hypoxic trophoblast cells, but the miR-140-5p-mediated effect in hypoxic trophoblast cells was abrogated by overexpressing FSTL3. miR-140-5p from huc-MSCs-EXO suppresses PE through repressing FSTL3.

In Vitro Model of Human Trophoblast in Early Placentation

The complex process of placental implantation and development affects trophoblast progenitors and uterine cells through the regulation of transcription factors, cytokines, adhesion receptors and their ligands. Differentiation of trophoblast precursors in the trophectoderm of early ontogenesis, caused by the transcription factors, such as CDX2, TEAD4, Eomes and GATA3, leads to the formation of cytotrophoblast and syncytiotrophoblast populations. The molecular mechanisms involved in placental formation inside the human body along with the specification and differentiation of trophoblast cell lines are, mostly due to the lack of suitable cell models, not sufficiently elucidated. This review is an evaluation of current technologies, which are used to study the behavior of human trophoblasts and other placental cells, as well as their ability to represent physiological conditions both in vivo and in vitro. An in vitro 3D model with a characteristic phenotype is of great benefit for the study of placental physiology. At the same time, it provides great support for future modeling of placental disease.

Human Placental Intracellular Cholesterol Transport: A Focus on Lysosomal and Mitochondrial Dysfunction and Oxidative Stress

The placenta participates in cholesterol biosynthesis and metabolism and regulates exchange between the maternal and fetal compartments. The fetus has high cholesterol requirements, and it is taken up and synthesized at elevated rates during pregnancy. In placental cells, the major source of cholesterol is the internalization of lipoprotein particles from maternal circulation by mechanisms that are not fully understood. As in hepatocytes, syncytiotrophoblast uptake of lipoprotein cholesterol involves lipoprotein receptors such as low-density lipoprotein receptor (LDLR) and scavenger receptor class B type I (SR-BI). Efflux outside the cells requires proteins such as the ATP-binding cassette (ABC) transporters ABCA1 and ABCG1. However, mechanisms associated with intracellular traffic of cholesterol in syncytiotrophoblasts are mostly unknown. In hepatocytes, uptaken cholesterol is transported to acidic late endosomes (LE) and lysosomes (LY). Proteins such as Niemann–Pick type C 1 (NPC1), NPC2, and StAR related lipid transfer domain containing 3 (STARD3) are required for cholesterol exit from the LE/LY. These proteins transfer cholesterol from the lumen of the LE/LY into the LE/LY-limiting membrane and then export it to the endoplasmic reticulum, mitochondria, or plasma membrane. Although the production, metabolism, and transport of cholesterol in placental cells are well explored, there is little information on the role of proteins related to intracellular cholesterol traffic in placental cells during physiological or pathological pregnancies. Such studies would be relevant for understanding fetal and placental cholesterol management. Oxidative stress, induced by generating excess reactive oxygen species (ROS), plays a critical role in regulating various cellular and biological functions and has emerged as a critical common mechanism after lysosomal and mitochondrial dysfunction. This review discusses the role of cholesterol, lysosomal and mitochondrial dysfunction, and ROS in the development and progression of hypercholesterolemic pregnancies.

The Role of High Concentrations of Homocysteine for the Development of Fetal Growth Restriction

OBJECTIVE

 To assess homocysteine (Hcy) levels in the three trimesters of pregnancy in women with fetal growth restriction (FGR) and to evaluate the role of Hcy as a possible predictor of FGR.

METHODS

 A total of 315 singleton pregnant women were included in the present prospective cohort study and were monitored since the 1^st trimester of pregnancy before delivery. Newborns were monitored for the first 7 days of life. Patients who had risk factors for FGR were excluded. Fetal growth restriction was defined according to uterine fundal height (< 10 percentile), ultrasound fetometry (< 5 percentile), and anthropometry of newborns (< 5 percentile). The concentrations of Hcy were detected at between 10 and 14, between 20 and 24, and between 30 and 34 weeks of pregnancy by enzyme-linked immunosorbent assay (ELISA). Receiver operating characteristics (ROC) curve test and diagnostic odds ratio (DOR) were performed to evaluate the results of ELISA.

RESULTS

 The concentration of Hcy in patients with FGR was 19.65 umol/L at between 10 and 14 weeks, compared with 9.28 umol/L in patients with normal fetal growth (p < 0.0001). The optimal cut-off level for Hcy in the 1^st trimester of pregnancy was > 13.9 umol/L with AUC 0.788, sensitivity of 75%, specificity of 83.6%, and DOR of 15.2.

CONCLUSION

 Assessment of serum Hcy concentration may be used as a predictor of FGR, with the highest diagnostic utility in the 1^st trimester of pregnancy.

The Pivotal Role of the Placenta in Normal and Pathological Pregnancies: A Focus on Preeclampsia, Fetal Growth Restriction, and Maternal Chronic Venous Disease

The placenta is a central structure in pregnancy and has pleiotropic functions. This organ grows incredibly rapidly during this period, acting as a mastermind behind different fetal and maternal processes. The relevance of the placenta extends far beyond the pregnancy, being crucial for fetal programming before birth. Having integrative knowledge of this maternofetal structure helps significantly in understanding the development of pregnancy either in a proper or pathophysiological context. Thus, the aim of this review is to summarize the main features of the placenta, with a special focus on its early development, cytoarchitecture, immunology, and functions in non-pathological conditions. In contraposition, the role of the placenta is examined in preeclampsia, a worrisome hypertensive disorder of pregnancy, in order to describe the pathophysiological implications of the placenta in this disease. Likewise, dysfunction of the placenta in fetal growth restriction, a major consequence of preeclampsia, is also discussed, emphasizing the potential clinical strategies derived. Finally, the emerging role of the placenta in maternal chronic venous disease either as a causative agent or as a consequence of the disease is equally treated.

Puerarin attenuates preeclampsia-induced trophoblast mobility loss and inflammation by modulating miR-181b-5p/RBAK axis

PROBLEM

Preeclampsia (PE) is a serious pregnancy complication characterized by inflammation and impaired trophoblast motility. Puerarin (Pue) is a functional compound with anti-PE potential. The current study aimed to explore the therapeutic effects of Pue on PE as well as the associated mechanism by focusing on the interaction between Pue and microRNAs (miRs).

METHODS OF STUDY

Human villous trophoblast HTR-8/SVneo cells were treated with TNF-α and Pue, and a change in miR expression profile was determined. The anti-PE effects of Pue were validated in rat models by measuring blood pressure, 24-h proteinuria, and cytokine levels. The mechanism was explored by focusing on miR-181b-5p/RBAK axis.

RESULTS

The induction of PE increased blood pressure and 24-h proteinuria, and induced TNF-α, IL-1β, and IL-6 levels, which was reversed by Pue. In in vitro assays, TNF-α suppressed viability, induced apoptosis and inflammatory response, and inhibited migration in trophoblasts, which was attenuated by Pue. At molecular level, the expression level of miR-181b-5p was both induced in vivo and in vitro with the development of PE symptoms, contributing to the inhibited expression of RBAK. The induced expression of miR-181b-5p under Pue treatment showed that the reinduction of miR-181b-5p counteracted the effects of Pue, indicating the key role of the miR in the protective effects of Pue against PE.

CONCLUSIONS

The current study verified the anti-PE function of Pue: the compound suppressed inflammatory response associated with PE, and improved trophoblast motility. The effects depended on the inhibition of miR-181b-5p that inhibited the expression of RBAK.

Criminal of Adverse Pregnant Outcomes: A Perspective From Thyroid Hormone Disturbance Caused by SARS-CoV-2

Nowadays, emerging evidence has shown adverse pregnancy outcomes, including preterm birth, preeclampsia, cesarean, and perinatal death, occurring in pregnant women after getting infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), but the underlying mechanisms remain elusive. Thyroid hormone disturbance has been unveiled consistently in various studies. As commonly known, thyroid hormone is vital for promoting pregnancy and optimal fetal growth and development. Even mild thyroid dysfunction can cause adverse pregnancy outcomes. We explored and summarized possible mechanisms of thyroid hormone abnormality in pregnant women after coronavirus disease 2019 (COVID-19) infection and made a scientific thypothesis that adverse pregnancy outcomes can be the result of thyroid hormone disorder during COVID-19. In which case, we accentuate the importance of thyroid hormone surveillance for COVID-19-infected pregnant women.

α-tocopherol prevents oxidative stress-induced proliferative dysfunction in first-trimester human placental (HTR-8/SVneo) cells

Extravillous trophoblasts (EVTs) are the main participants in the process of placentation, an early process critical for placental growth and function involving an adequate invasion and complete remodelling of the maternal spiral arteries during early pregnancy. An increase in oxidative stress during pregnancy is associated with the onset and progression of several pregnancy disorders, including preeclampsia and gestational diabetes mellitus and it also occurs due to exposure of pregnant women to some xenobiotics (eg. alcohol). This study aimed to investigate how oxidative stress affects EVTs, and the ability of several distinct antioxidant agents to prevent these changes. For this, we exposed HTR8/SVneo cells to tert-butylhydroperoxide (0.5 μM; 24 h), which was able to increase lipid peroxidation and protein carbonyl levels. Under these conditions, there was a decrease in proliferation rates, culture growth, migratory and angiogenic capacities and an increase in the apoptosis rates. The antiproliferative effect of TBH was supressed by simultaneous treatment of the cells with α-tocopherol, but other antioxidants (vitamin C, allopurinol, apocynin, N-acetylcysteine, quercetin and resveratrol) were ineffective. α-tocopherol was also able to abolish the effect of TBH on lipid peroxidation and protein carbonyl levels. Overall, our results show that oxidative stress interferes with EVT characteristics essential for the placentation process, which may contribute to the association between oxidative stress and pregnancy disorders. Our results also show that the nature of the in vitro model of oxidative stress-induction is an important determinant of the cellular consequences of oxidative stress and, therefore, of the efficacy of antioxidants.

Hyperosmolarity Impairs Human Extravillous Trophoblast Differentiation by Caveolae Internalization

We recently reported that an intact caveolar structure is necessary for adequate cell migration and tubulogenesis of the human extravillous trophoblast (EVT) cells. Emerging evidence supports that hyperosmolarity induces the internalization of caveolae into the cytoplasm and accelerates their turnover. Furthermore, signaling pathways associated with the regulation of trophoblast differentiation are localized in caveolae. We hypothesized that hyperosmolarity impairs EVT differentiation and caveolae/caveolin−1 (Cav-1) participates in this process. EVT cells (Swan 71 cell line) were cultured in complete Dulbecco’s Modified Eagle Medium/Nutrient Mixture F-12 and exposed to hyperosmolar condition (generated by the addition of 100 mM sucrose). Hyperosmolarity altered the EVT cell migration and the formation of tube-like structures. In addition, cell invasion was decreased along with a reduction in the latent and active forms of matrix metalloproteinase-2 (MMP−2) secreted by these cells. With respect to Cav-1 protein abundance, we found that hyperosmolarity enhanced its degradation by the lysosomal pathway. Accordingly, in the hyperosmolar condition, we also observed a significant increase in the number of vacuoles and the internalization of the caveolae into the cytoplasm. Taken together, our findings suggest that hyperosmolarity may induce caveolae internalization and increase their turnover, compromising the normal differentiation of EVT cells.

Circular RNA circ_0032962 promotes trophoblast cell progression as ceRNA to target PBX3 via sponging miR-326 in preeclampsia

Preeclampsia (PE) is the leading cause of maternal deaths in primipara. It is mainly characterized by defect migration and invasion of trophoblast cells. Circular RNAs (circRNAs) have been widely reported to be associated with PE progression. This study is designed to explore the role and mechanism of circ_0032962 on trophoblast cell behavior. Circ_0032962, microRNA-326 (miR-326), and Pre-B-cell leukemia homeobox 3 (PBX3) levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR). Cell proliferation ability, migration, and invasion were measured by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), Colony formation, wound healing, and transwell assays. Protein levels of E-cadherin, Vimentin, N-cadherin, and PBX3 were examined by western blot assay. The binding relationship between miR-326 and circ_0032962 or PBX3 was predicted by circular RNA Interactome or Starbase and then verified by a dual-luciferase reporter assay. Circ_0032962 and PBX3 levels were declined in placenta tissues from preeclampsia patients, and miR-326 was elevated. Apart from that, circ_0032962 knockdown could suppress cell proliferation ability, migration, invasion, and epithelial-mesenchymal transition (EMT) in trophoblast cells. Mechanically, circ_0032962 could affect PBX3 expression through sponging miR-326. Circ_0032962 could contribute to trophoblast cell growth ability and metastasis partly by regulating the miR-326/PBX3 axis, providing a novel insight into the pathogenesis and treatment of PE.

Vascular Dysfunction in Preeclampsia

Preeclampsia is a life-threatening pregnancy-associated cardiovascular disorder characterized by hypertension and proteinuria at 20 weeks of gestation. Though its exact underlying cause is not precisely defined and likely heterogenous, a plethora of research indicates that in some women with preeclampsia, both maternal and placental vascular dysfunction plays a role in the pathogenesis and can persist into the postpartum period. Potential abnormalities include impaired placentation, incomplete spiral artery remodeling, and endothelial damage, which are further propagated by immune factors, mitochondrial stress, and an imbalance of pro- and antiangiogenic substances. While the field has progressed, current gaps in knowledge include detailed initial molecular mechanisms and effective treatment options. Newfound evidence indicates that vasopressin is an early mediator and biomarker of the disorder, and promising future therapeutic avenues include mitigating mitochondrial dysfunction, excess oxidative stress, and the resulting inflammatory state. In this review, we provide a detailed overview of vascular defects present during preeclampsia and connect well-established notions to newer discoveries at the molecular, cellular, and whole-organism levels.

Disease-specific extracellular matrix composition regulates placental trophoblast fusion efficiency

The placental syncytiotrophoblast is a multinucleated layer that regulates transport between the mother and fetus. Fusion of trophoblasts is essential to form this layer, but this process can be disrupted in pregnancy-related disorders such as preeclampsia. Disease progression is also associated with changes in the extracellular matrix (ECM), but whether disease-specific ECM compositions play any causal role in establishing syncytiotrophoblast disease phenotypes remains unknown. Here, we develop a decellularization-based platform to isolate and characterize the role of human placental ECM composition on cell function, while controlling for the confounding effects of matrix structure and mechanics that can arise in conventional tissue decellularization/recellularization experiments. Using this approach, we demonstrate that ECM compositional changes that occur in preeclampsia have a statistically significant effect on adhesion, spreading, and fusion of placental trophoblasts. Proteomic analysis of ECM content then allowed us to identify and recreate selected differences in matrix composition; indicating that replacement of normally present Type IV Collagen by Type I Collagen in preeclampsia significantly affects fusion efficiency. These results indicate that disease-specific matrix compositions can play an important role in trophoblast fusion, suggesting novel matrix-targeting therapeutic strategies for pregnancy-related disorders. More broadly, this work demonstrates the utility of a decellularization-based approach in understanding the functional contributions of matrix composition in driving cellular disease phenotypes.

Exosomes derived from placental trophoblast cells regulate endometrial epithelial receptivity in dairy cows during pregnancy

Inadequate fetomaternal interactions could directly lead to pregnancy failure in dairy cows. Exosomes are widely involved in endometrial matrix remodeling, immune function changes, placental development, and other processes of embryo implantation and pregnancy in dairy cows. However, the role of exosomes derived from placental trophoblast cells in regulating the receptivity of endometrial cells and facilitating fetomaternal interaction remains unclear. In this study, bovine trophoblast cells (BTCs) were obtained from bovine placenta and immortalized by transfection with telomerase reverse transcriptase (TERT). Immortalized BTCs still possess the basic and key properties of primary BTCs without exhibiting any neoplastic transformation signs. Subsequently, the effect of trophoblast-derived exosomes (TDEs) on endometrial receptivity in endometrial epithelial cells (EECs) was determined, and the mechanism whereby TDEs and their proteins participate in the fetomaternal interaction during bovine pregnancy were explored. EECs were co-cultured with the exosomes derived from BTCs treated with progesterone (P4). Such treatment enhanced the expression of the endometrial receptivity factors, integrin αv, β3, Wnt7a, and MUC1 by changing the extracellular environment, metabolism, and redox balance in EECs via proteome alignment, compared with no treatment according to the DIA quantitation analysis. Our study demonstrated that trophoblast-derived exosome proteins are one of the most critical elements in fetomaternal interaction, and their changes may act as a key signal in altering endometrial receptivity and provide a potential target for improving fertility.

CXCL5 Downregulation in Villous Tissue Is Correlated With Recurrent Spontaneous Abortion

Recurrent spontaneous abortion (RSA) affects 5% of childbearing-age women worldwide. Inadequate trophoblast invasion is one of the main reasons for the development of RSA; however, the underlying molecular mechanisms for RSA have not been fully understood, and further explanation is urgently needed. C-X-C motif chemokine ligand 5 (CXCL5) is reported to contribute to the invasion of cancer cells, and its aberrant expression is associated with the cellular process of tumor pathology. Considering the high behavioral similarity between trophoblast cells and cancer cells, we hypothesized that CXCL5 may influence trophoblast invasion, and its expression levels in villous tissue may be correlated with RSA. In this study, we firstly investigated the CXCL5 expression in placental villous tissues of 15 RSA patients and 13 control patients, and the results showed that CXCL5 levels were significantly lower in villous tissue from RSA patients than those of the controls. Further in vitro experiments presented that recombinant human CXCL5 can enhance trophoblast migration, invasion, and epithelial-to-mesenchymal transition (EMT) process. We also demonstrated that CXCL5 exerted these effects on trophoblast cells through PI3K/AKT/ERK1/2 signaling pathway. In conclusion, these data indicate that CXCL5 downregulation in human villous tissue is correlated with RSA. Additionally, we found that estrogen, progesterone, human chorionic gonadotropin, and decidual stromal cells can regulate CXCL5 and chemokine receptor 2 (CXCR2) expression of trophoblast in a cell manner.

Overexpression of let-7b exerts beneficial effects on the functions of human placental trophoblasts by activating the ERK1/2 signaling pathway

The present work aimed to explore let-7b's molecular mechanisms that regulate the functions of placental trophoblasts and to examine placental let-7b expression in human pre-eclampsia (PE). Human trophoblast HTR-8/SVneo cells underwent transduction with control and let-7b overexpressing lentiviruses, respectively. Cell proliferation assessment utilized cell counting kit-8 (CCK-8) and 5-ethynyl-2'-deoxyuridine (EdU) assays. Apoptosis, autophagy, inflammation, epithelial-to-mesenchymal transition (EMT), and ERK1/2 signaling-associated proteins were assessed by immunoblot. Placental tissue samples were collected from women with normal pregnancy (n = 20) and PE patients (n = 14). Let-7b overexpression in HTR-8/SVneo cells remarkably induced cell proliferation and invasion, suppressed apoptosis and autophagy, and resulted in decreased tumor necrosis factorα (TNF-α) expression and increased interleukin 6 (IL-6) expression in trophoblasts. Notably, the beneficial effects of let-7b overexpression, including cell invasion and EMT, were largely reversed by treatment with U0126, an indirect ERK1/2 signaling inhibitor, in these cells. TGF-β receptor type-1 (TGFBR1) overexpression weakened let-7b's functions in ERK pathway activation and invasion in trophoblasts. Placental tissue specimens from PE cases demonstrated significantly lower let-7b expression compared with normal controls. Overexpression of let-7b exerts beneficial effects on the functions of human placental trophoblasts via ERK1/2 signaling, and placental let-7b is downregulated in human PE. These findings suggest let-7b is a promising biomarker for the prospective diagnosis and targeted therapy of PE.

Role of lncRNA BCYRN1 in trophoblast cell physiology and pathogenesis of preeclampsia

Long non-coding RNAs (lncRNAs) may play a key role in the pathogenesis of preeclampsia (PE). The present study investigated the role of the lncRNA brain cytoplasmic RNA 1 (BCYRN1) in PE. A total of 30 patients with severe PE (SPE) and 30 patients with mild PE (MPE) were recruited, whilst 30 healthy pregnant individuals were enrolled as controls. Placental tissues of enrolled subjects were collected after delivery. The clinical data of pregnant women and newborns were recorded before the correlation between BCYRN1 expression and clinical characteristics was analyzed. Furthermore, HTR-8/SVneo cells were transfected with BCYRN1 overexpression plasmids and BCYRN1 small interfering (si)RNA. Cell Counting Kit-8, Transwell, flow cytometry and tube formation assays were used to detect the function of BCYRN1 in HTR-8/SVneo cells. Reverse transcription-quantitative PCR was used to detect BCYRN1 expression in placental tissues and HTR-8/SVneo cells. Western blotting was used to detect the protein expression levels of Wnt1 and β-catenin. BCYRN1 expression was lower in placenta with mild PE compared with in normal placenta, and was in turn lower in placenta with severe PE. BCYRN1 was negatively correlated with systolic blood pressure and 24-h urinary protein in patients with PE. BCYRN1 siRNA inhibited cell viability, migration, invasion and tube forming abilities whilst increasing apoptosis. By contrast, BCYRN1 overexpression conferred opposite effects. The levels of Wnt1 and β-catenin expression in the cells and placental tissues were next measured. Cells overexpressing BCYRN1 were further treated with the Wnt pathway inhibitor XAV939. Wnt1 and β-catenin expression were elevated when BCYRN1 was overexpressed, but were decreased after BCYRN1 knockdown. XAV939 attenuated the effect of BCYRN1 overexpression on HTR-8/SVneo cells. Overall, the resulted indicated that upregulation of BCYRN1 increased trophoblast viability and prevented apoptosis by activating the Wnt/β-catenin pathway to delay PE onset.

Prothrombotic state associated with preeclampsia

PURPOSE OF REVIEW

Preeclampsia is a common complication of pregnancy and contributes significantly to maternal and fetal morbidity and mortality. A protective hypercoagulable state is often developed during late pregnancy and can evolve into a prothrombotic state in patients with preeclampsia. The underlying mechanism of this prothrombotic transition remains poorly understood. We discuss recent progress in understanding the pathophysiology of preeclampsia and associated prothrombotic state.

RECENT FINDINGS

The hypercoagulable state developed during pregnancy is initiated by placental factors and progresses into the prothrombotic state in preeclampsia when the placenta is subjected ischemic and oxidative injuries. The cause of the preeclampsia-induced prothrombotic state is multifactorial, involving not only placental factors but also maternal conditions, which include genetic predisposition, preexisting medical conditions, and conditions acquired during pregnancy. Endotheliopathy is the primary pathology of preeclampsia and contributes to the prothrombotic state by inducing the dysregulation of coagulation, platelets, and adhesive ligands.

SUMMARY

Patients with preeclampsia often develop a severe prothrombotic state that predisposes them to life-threatening thrombosis and thromboembolism during and after pregnancy. Early recognition and treatment of this prothrombotic state can improve maternal and infant outcomes of preeclampsia patients.

Fetal-placental blood flow and neurodevelopment in childhood: population-based neuroimaging study

OBJECTIVE

Antenatal Doppler measurements of the fetal umbilical and cerebral circulations can predict perinatal complications; however, it is unclear if subtle variations in antenatal Doppler measurements are associated with long-term neurodevelopmental outcome. In this study, we examined whether antenatal Doppler measurements of the fetal-placental circulation are associated with cognitive and motor abilities and brain morphology in childhood.

METHODS

To evaluate differences in long-term sequelae across the continuum of the umbilical and cerebral artery circulations in the general population, we utilized a population-based longitudinal cohort study approach. In women from the Generation R study, we measured second- and third-trimester umbilical artery pulsatility index (UA-PI). Children underwent non-verbal intelligence testing at 4-8 years of age, and at 8-12 years they underwent finger-tapping tests to measure fine motor skills, balance beam tests to measure gross motor skills and brain magnetic resonance imaging. We assessed the relationships between prenatal UA-PI and neurodevelopmental outcome using linear regression. We adjusted for child age and sex, maternal age, education, parity and smoking status.

RESULTS

The study sample included 2803 pregnancies. Higher third-trimester UA-PI was associated with poorer fine motor performance (0.41 (95% CI, 0.11-0.70) fewer taps on the finger-tapping test per 1 SD higher UA-PI) and gross motor performance (0.64 (95% CI, 0.20-1.08) fewer steps on the balance beam test per 1 SD higher UA-PI). One SD higher third-trimester UA-PI was also associated with 0.65 (95% CI, 0.04-1.25) points lower intelligence quotient; however, unlike the associations with motor abilities, this finding did not persist after correction for multiple testing. Higher second-trimester UA-PI was associated with smaller brain volume (6.1 (95% CI, 1.0-11.3) cm³ reduction per 1 SD higher UA-PI), but the association did not persist after correction for multiple testing.

CONCLUSION

Higher placental vascular resistance may have mild adverse effects on neurodevelopmental outcome at school age. While these effects are subtle at population level, we encourage future research into the role of early circulation in brain development. This information could be used to develop targeted interventions. © 2020 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

LINC00473 downregulation facilitates trophoblast cell migration and invasion via the miR-15a-5p/LITAF axis in pre-eclampsia

More and more evidence has identified that long non-coding RNAs (lncRNAs) are involved in various biological process of numerous diseases. It has been reported that long intergenic non-protein coding RNA 473 (LINC00473) was associated with pre-eclampsia (PE) development. However, role and molecular mechanism of LINC00473 in PE remains elusive. Therefore, we designed this research to figure out the specific biological function of LINC00473 in trophoblasts. Firstly, we testified expressions of LINC00473 in trophoblasts of PE with RT-qPCR analysis. Then, to probe biological function of LINC00473 in trophoblasts of PE, CCK-8 assay, trans-well assays and western blot analysis were conducted in Wish and JAR cells. As for verifying interaction of microRNA-15a-5p (miR-15a-5p) and LINC00473 or lipopolysaccharide induced TNF factor (LITAF), RNA pull-down and luciferase reporter assays were carried out. Finally, rescue experiments were conducted to probe regulatory pattern of the LINC00473/miR-15a-5p/LITAF axis in trophoblasts of PE. As a result, LINC00473 presented a significant upregulation in trophoblasts of PE. Moreover, LINC00473 knockdown induced trophoblast viability, migration, invasion, and epithelial-to-mesenchymal transition (EMT) in trophoblasts. Additionally, miR-15a-5p interacted with LINC00473 and miR-15a-5p was negatively regulated by LINC00473 in trophoblasts. Simultaneously, miR-15a-5p negatively modulated LITAF in trophoblasts. Moreover, LITAF overexpression or miR-15a-5p downregulation reversed the promotive impact of silenced LINC00473 on trophoblast viability, migration, invasion and EMT. In conclusion, LINC00473 regulated migration and invasion in trophoblasts via the miR-15a-5p/LITAF axis. Our study may provide a novel insight for clinical treatment of PE.

VEGF Maintains Maternal Vascular Space Homeostasis in the Mouse Placenta through Modulation of Trophoblast Giant Cell Functions

Vascular endothelial growth factor (VEGF) is an angiogenic growth factor that acts primarily on endothelial cells, but numerous studies suggest that VEGF also acts on non-endothelial cells, including trophoblast cells. Inhibition of VEGF signaling by excess production of the endogenous soluble VEGF receptor sFlt1 in trophoblast cells has been implicated in several pregnancy complications. Our previous studies and other reports have shown that VEGF directly regulates placental vascular development and functions and that excess VEGF production adversely affects placental vascular development. Trophoblast giant cells (TGCs) line the maternal side of the placental vasculature in mice and function like endothelial cells. In this study, we specifically examined the effect of excess VEGF signaling on TGC development associated with defective placental vascular development using two mouse models an endometrial VEGF overexpression model and a placenta-specific sFlt1 knockdown model. Placentas of endometrial VEGF-overexpressing dams at embryonic days (E) 11.5 and 14.5 showed dramatic enlargement of the venous maternal spaces in junctional zones. The size and number of the parietal TGCs that line these venous spaces in the placenta were also significantly increased. Although junctional zone venous blood spaces from control and VEGF-overexpressing dams were not markedly different in size at E17.5, the number and size of P-TGCs were both significantly increased in the placentas from VEGF-overexpressing dams. In sFlt1 knockdown placentas, however, there was a significant increase in the size of the sinusoidal TGC-lined, alkaline phosphatase-positive maternal blood spaces in the labyrinth. These results suggest that VEGF signaling plays an important role in maintaining the homeostasis of the maternal vascular space in the mouse placenta through modulation of TGC development and differentiation, similar to the effect of VEGF on endothelial cells in other vascular beds.

Prokineticin 1-prokineticin receptor 1 signaling in trophoblast promotes embryo implantation and placenta development

Successful pregnancy establishment in mammals depends on proper embryo-maternal communication. Prokineticin 1 (PROK1) is a secretory protein that exerts pleiotropic functions in various tissues. Despite the studies that have primarily been performed with human cell lines and mice, the function of PROK1 in trophoblasts has still not been fully elucidated. Hence, the aim of this study was to establish the role of PROK1 in trophoblasts during implantation and placentation. Prokineticin 1 mRNA was elevated in porcine trophoblasts during implantation and the early placentation period. Furthermore, we reveal that PROK1–PROKR1 signaling induces the expression of genes involved in the regulation of angiogenesis, immunological response, trophoblast cell adhesion, invasion, and proliferation, as well as stimulating phosphorylation of MAPK and PTK2. Ingenuity Pathway Analysis identified the aforementioned and also other functions associated with PROK1-regulated genes/proteins, such as cell-to-cell contact, epithelial tissue differentiation, Ca2+ release, lipid synthesis, and chemotaxis. We also showed evidence that PROK1 acting via PROKR1 increased trophoblast cell proliferation and adhesion. The PROK1-stimulated cell proliferation was mediated by PI3K/AKT/mTOR, MAPK, and cAMP, whereas adhesion was mediated by MAPK and/or PI3K/AKT signaling pathways. Concluding, our study suggests that PROK1 plays a pleiotropic role in trophoblast function during implantation and early placentation.

Expression of lncRNA TINCR in the placenta of patients with pre-eclampsia and its effect on the biological behaviours of trophoblasts

To explore the effect of lncRNA TINCR on the biological behaviours of trophoblasts, we detected and analyzed the expression of terminal differentiation-induced non-protein coding RNA (TINCR) in the placenta tissues of pre-eclamptic and non-pre-eclamptic pregnant women. The gain- and loss-of-function of TINCR was performed to examine the proliferation, migration and invasion abilities of Htr-8/Svneo cells. The levels of epithelial-mesenchymal transition (EMT)-related proteins, cyclin and Wnt/β-catenin pathway were detected. High expression of lncRNA TINCR appeared in placental tissues of patients with pre-eclampsia. The proliferation, invasion and migration of Htr-8/Svneo cells were promoted by TINCR downregulation; the cells were transited from G0/G1 to S phase; and EMT was promoted and the Wnt/β-catenin pathway was activated. In summary, the downregulation of lncRNA TINCR activated the Wnt/β-catenin pathway and promoted the proliferation, invasion and migration of Htr-8/Svneo cells. This study may provide a theoretical basis for treatment of patients with pre-eclampsia.

Regulation of placentation by the transforming growth factor beta superfamily†

During pregnancy, there is increased expression of some cytokines at the fetal-maternal interface; and the clarification of their roles in trophoblast-endometrium interactions is crucial to understanding the mechanism of placentation. This review addresses the up-to-date reported mechanisms by which the members of the transforming growth factor beta superfamily regulate trophoblast proliferation, differentiation, and invasion of the decidua, which are the main phases of placentation. The available information shows that these cytokines regulate placentation in somehow a synergistic and an antagonistic manner; and that dysregulation of their levels can lead to aberrant placentation. Nevertheless, prospective studies are needed to reconcile some conflicting reports; and identify some unknown mediators involved in the actions of these cytokines before their detailed mechanistic regulation of human placentation could be fully characterized. The TGF beta superfamily are expressed in the placenta, and regulate the process of placentation through the activation of several signaling pathways.

The interplay between thyroid hormones and the placenta: a comprehensive review†

Thyroid hormones (THs) regulate a number of metabolic processes during pregnancy. After implantation, the placenta forms and enhances embryonic growth and development. Dysregulated maternal THs signaling has been observed in malplacentation-mediated pregnancy complications such as preeclampsia, miscarriage, and intrauterine growth restriction (IUGR), but the molecular mechanisms involved in this association have not been fully characterized. In this review, we have discussed THs signaling and its roles in trophoblast proliferation, trophoblast differentiation, trophoblast invasion of the decidua, and decidual angiogenesis. We have also explored the relationship between specific pregnancy complications and placental THs transporters, deiodinases, and THs receptors. In addition, we have examined the effects of specific endocrine disruptors on placental THs signaling. The available evidence indicates that THs signaling is involved in the formation and functioning of the placenta and serves as the basis for understanding the pathogenesis and pathophysiology of dysthyroidism-associated pregnancy complications such as preeclampsia, miscarriage, and IUGR.

Uterine Vascular Control Preconception and During Pregnancy

Successful pregnancy and reproduction are dependent on adequate uterine blood flow, placental perfusion, and vascular responsivity to fetal demands. The ability to support pregnancy centers on systemic adaptation and endometrial preparation through decidualization, embryonic implantation, trophoblast invasion, arterial/arteriolar reactivity, and vascular remodeling. These adaptations occur through responsiveness to endocrine signaling and local uteroplacental mediators. The purpose of this article is to highlight the current knowledge associated with vascular remodeling and responsivity during uterine preparation for and during pregnancy. We focus on maternal cardiovascular systemic and uterine modifications, endometrial decidualization, implantation and invasion, uterine and spiral artery remodeling, local uterine regulatory mechanisms, placentation, and pathological consequences of vascular dysfunction during pregnancy. © 2021 American Physiological Society. Compr Physiol 11:1-23, 2021.

Placental trophoblast syncytialization potentiates macropinocytosis via mTOR signaling to adapt to reduced amino acid supply

During pregnancy, the appropriate allocation of nutrients between the mother and the fetus is dominated by maternal-fetal interactions, which is primarily governed by the placenta. The syncytiotrophoblast (STB) lining at the outer surface of the placental villi is directly bathed in maternal blood and controls feto-maternal exchange. The STB is the largest multinucleated cell type in the human body, and is formed through syncytialization of the mononucleated cytotrophoblast. However, the physiological advantage of forming such an extensively multinucleated cellular structure remains poorly understood. Here, we discover that the STB uniquely adapts to nutrient stress by inducing the macropinocytosis machinery through repression of mammalian target of rapamycin (mTOR) signaling. In primary human trophoblasts and in trophoblast cell lines, differentiation toward a syncytium triggers macropinocytosis, which is greatly enhanced during amino acid shortage, induced by inhibiting mTOR signaling. Moreover, inhibiting mTOR in pregnant mice markedly stimulates macropinocytosis in the syncytium. Blocking macropinocytosis worsens the phenotypes of fetal growth restriction caused by mTOR-inhibition. Consistently, placentas derived from fetal growth restriction patients display: 1) Repressed mTOR signaling, 2) increased syncytialization, and 3) enhanced macropinocytosis. Together, our findings suggest that the unique ability of STB to undergo macropinocytosis serves as an essential adaptation to the cellular nutrient status, and support fetal survival and growth under nutrient deprivation.

Analysis of Circulating microRNA Signatures and Preeclampsia Development

microRNAs are important regulators of cell processes and have been proposed as potential preeclampsia biomarkers. We evaluated serum microRNA expression profiling to identify microRNAs involved in preeclampsia development. Serum microRNA expression profiling was evaluated at 12, 16, and 20 weeks of gestation (WG), and at the time of preeclampsia diagnosis. Two groups were evaluated using TaqMan low-density array plates: a control group with 18 normotensive pregnant women and a case group with 16 patients who developed preeclampsia during the follow-up period. Fifty-three circulating microRNAs were differentially expressed between groups (p < 0.05). Compared with controls, hsa-miR-628-3p showed the highest relative quantity values (at 12 WG = 7.7 and at 20 WG = 3.45) and the hsa-miRs -151a-3p and -573 remained differentially expressed from 16 to 20 WG (p < 0.05). Signaling pathways including cancer-related, axon guidance, Neurotrophin, GnRH, VEGF, and B/T cell receptor, were most commonly altered. Further target gene prediction revealed that nuclear factor of activated T-cells 5 gene was included among the transcriptional targets of preeclampsia-modulated microRNAs. Specific microRNAs including hsa-miRs -628-3p, -151a-3p, and -573 were differentially expressed in serum of pregnant women before they developed preeclampsia compared with controls and their participation in the preeclampsia development should be considered.

Autophagy Process in Trophoblast Cells Invasion and Differentiation: Similitude and Differences With Cancer Cells

Early human placental development begins with blastocyst implantation, then the trophoblast differentiates and originates the cells required for a proper fetal nutrition and placental implantation. Among them, extravillous trophoblast corresponds to a non-proliferating trophoblast highly invasive that allows the vascular remodeling which is essential for appropriate placental perfusion and to maintain the adequate fetal growth. This process involves different placental cell types as well as molecules that allow cell growth, cellular adhesion, tissular remodeling, and immune tolerance. Remarkably, some of the cellular processes required for proper placentation are common between placental and cancer cells to finally support tumor growth. Indeed, as in placentation trophoblasts invade and migrate, cancer cells invade and migrate to promote tumor metastasis. However, while these processes respond to a controlled program in trophoblasts, in cancer cells this regulation is lost. Interestingly, it has been shown that autophagy, a process responsible for the degradation of damaged proteins and organelles to maintain cellular homeostasis, is required for invasion of trophoblast cells and for vascular remodeling during placentation. In cancer cells, autophagy has a dual role, as it has been shown both as tumor promoter and inhibitor, depending on the stage and tumor considered. In this review, we summarized the similarities and differences between trophoblast cell invasion and cancer cell metastasis specifically evaluating the role of autophagy in both processes.

Overexpression of miR-210-3p Impairs Extravillous Trophoblast Functions Associated with Uterine Spiral Artery Remodeling

Hsa-miR-210-3p has been reported to be upregulated in preeclampsia (PE); however, the functions of miR-210-3p in placental development are not fully understood, and, consequently, miR-210-3p’s role in the pathogenesis of PE is still under investigation. In this study, we found that overexpression of miR-210-3p reduced trophoblast migration and invasion, extravillous trophoblast (EVT) outgrowth in first trimester explants, expression of endovascular trophoblast (enEVT) markers and the ability of trophoblast to form endothelial-like networks. In addition, miR-210-3p overexpression significantly downregulated the mRNA levels of interleukin-1B and -8, as well as CXC motif ligand 1. These cytokines have been suggested to play a role in EVT invasion and the recruitment of immune cells to the spiral artery remodeling sites. We also showed that caudal-related homeobox transcription factor 2 (CDX2) is targeted by miR-210-3p and that CDX2 downregulation mimicked the observed effects of miR-210-3p upregulation in trophoblasts. These findings suggest that miR-210-3p may play a role in regulating events associated with enEVT functions and its overexpression could impair spiral artery remodeling, thereby contributing to PE.