Activation of the canonical wingless/T-cell factor signaling pathway promotes invasive differentiation of human trophoblast

Importance of the (Pro)renin Receptor in Activating the Renin-Angiotensin System During Normotensive and Preeclamptic Pregnancies

PURPOSE OF REVIEW

For a healthy pregnancy to occur, a controlled interplay between the maternal circulating renin-angiotensin-aldosterone system (RAAS), placental renin-angiotensin system (RAS) and intrarenal renin-angiotensin system (iRAS) is necessary. Functionally, both the RAAS and iRAS interact to maintain blood pressure and cardiac output, as well as fluid and electrolyte balance. The placental RAS is important for placental development while also influencing the maternal circulating RAAS and iRAS. This narrative review concentrates on the (pro)renin receptor ((P)RR) and its soluble form (s(P)RR) in the context of the hypertensive pregnancy pathology, preeclampsia.

RECENT FINDINGS

The (P)RR and the s(P)RR have become of particular interest as not only can they activate prorenin and renin, thus influencing levels of angiotensin II (Ang II), but s(P)RR has now been shown to directly interact with and stimulate the Angiotensin II type 1 receptor (AT1R). Levels of both placental (P)RR and maternal circulating s(P)RR are elevated in patients with preeclampsia. Furthermore, s(P)RR has been shown to increase blood pressure in non-pregnant and pregnant rats and mice. In preeclamptic pregnancies, which are characterised by maternal hypertension and impaired placental development and function, we propose that there is enhanced secretion of s(P)RR from the placenta into the maternal circulation. Due to its ability to both activate prorenin and act as an AT1R agonist, excess maternal circulating s(P)RR can act on both the maternal vasculature, and the kidney, leading to RAS over-activation. This results in dysregulation of the maternal circulating RAAS and overactivation of the iRAS, contributing to maternal hypertension, renal damage, and secondary changes to neurohumoral regulation of fluid and electrolyte balance, ultimately contributing to the pathophysiology of preeclampsia.

ISRIB facilitates the co-culture of human trophoblast stem cells and embryonic stem cells

The embryo-like structures (embryoids) constructed by aggregating embryonic stem cells (ESCs) and trophoblast stem cells (TSCs) have provided revolutionary tools for studying the intricate interaction between embryonic and extra-embryonic tissues during early embryonic development, which has been achieved in mice. However, due to the opposite dependence on some signalling pathways for in vitro culture of human ESCs (hESCs) and TSCs (hTSCs), particularly WNT and TGFβ signalling pathways, which limits the construction of human post-implantation embryoids by aggregating hESCs and hTSCs. To overcome this challenge, here, by screening 1639 chemicals, we found that an inhibitor of integrated stress response, ISRIB, can replace WNT agonists and TGFβ inhibitors to maintain the stemness and differentiation capacity of hTSCs. Thus, we developed an ISRIB-dependent in vitro culture medium for hTSCs, namely nTSM. Furthermore, we demonstrated that ISRIB could also maintain the hESC stemness. Using a 3D co-culture system (hESCs and hTSCs aggregate, ETA), we demonstrated that a 1:1 mixture of hESC culture medium (ESM) and nTSM improved the cell proliferation and organisation of both hESC- and hTSC-compartments and the lumenogenesis of hESC-compartment in ETAs. Overall, our study provided an ISRIB-dependent system for co-culturing hESCs and hTSCs, which facilitated the construction of human embryoids by aggregating hESCs and hTSCs.

SFRP2 suppresses trophoblast cell migration by inhibiting the Wnt/β‑catenin pathway

The present study investigates the role of Secreted Frizzled‑Related Protein 2 (SFRP2) in trophoblast cells, a key factor in preeclampsia (PE) progression. Elevated levels of Secreted Frizzled‑Related Protein 1/3/4/5 (SFRP1/3/4/5) are associated with PE, but the role of SFRP2 is unclear. We analyzed SFRP2 expression in PE placental tissue using the GSE10588 dataset and overexpressed SFRP2 in JEG‑3 cells via lentiviral transfection. The viability, migration, apoptosis, and proliferation of SFRP2‑overexpressing JEG‑3 cells were assessed using Cell Counting Kit‑8, Transwell assays, flow cytometry, and EdU staining. Additionally, we evaluated the impact of SFRP2 overexpression on key proteins in the Wnt/β‑catenin pathway and apoptosis markers (Bax, cleaved‑caspase 3, BCL‑2, MMP9, E‑cadherin, Wnt3a, Axin2, CyclinD1, c‑Myc, p‑β‑catenin, β‑catenin, phosphorylated Glycogen Synthase Kinase 3 beta (p‑GSK3β), and GSK3β) through western blotting. Results showed high SFRP2 mRNA and protein expression in PE placenta and JEG‑3 cells post‑transfection. SFRP2 overexpression significantly reduced JEG‑3 cell viability, proliferation, and migration, while increasing apoptosis. It also altered expression levels of Wnt pathway proteins, suggesting SFRP2's potential as a therapeutic target for PE by inhibiting trophoblast cell migration through the Wnt/β‑catenin signaling cascade.

NOTUM-MEDIATED WNT SILENCING DRIVES EXTRAVILLOUS TROPHOBLAST CELL LINEAGE DEVELOPMENT

Trophoblast stem (TS) cells have the unique capacity to differentiate into specialized cell types, including extravillous trophoblast (EVT) cells. EVT cells invade into and transform the uterus where they act to remodel the vasculature facilitating the redirection of maternal nutrients to the developing fetus. Disruptions in EVT cell development and function are at the core of pregnancy-related disease. WNT-activated signal transduction is a conserved regulator of morphogenesis of many organ systems, including the placenta. In human TS cells, activation of canonical WNT signaling is critical for maintenance of the TS cell stem state and its downregulation accompanies EVT cell differentiation. We show that aberrant WNT signaling undermines EVT cell differentiation. Notum, palmitoleoyl-protein carboxylesterase (NOTUM), a negative regulator of canonical WNT signaling, was prominently expressed in first trimester EVT cells developing in situ and upregulated in EVT cells derived from human TS cells. Furthermore, NOTUM was required for human TS cell differentiation to EVT cells. Activation of NOTUM in EVT cells is driven, at least in part, by endothelial PAS domain 1 (also called hypoxia-inducible factor 2 alpha). Collectively, our findings indicate that canonical WNT signaling is essential for maintenance of human trophoblast cell stemness and prevention of human TS cell differentiation. Downregulation of canonical WNT signaling via the actions of NOTUM is required for EVT cell differentiation.

YAP-mediated trophoblast dysfunction: the common pathway underlying pregnancy complications

Yes-associated protein (YAP) is a pivotal regulator in cellular proliferation, survival, differentiation, and migration, with significant roles in embryonic development, tissue repair, and tumorigenesis. At the maternal-fetal interface, emerging evidence underscores the importance of precisely regulated YAP activity in ensuring successful pregnancy initiation and progression. However, despite the established association between YAP dysregulation and adverse pregnancy outcomes, insights into the impact of aberrant YAP levels in fetal-derived, particularly trophoblast cells, and the ensuing dysfunction at the maternal-fetal interface remain limited. This review comprehensively examines YAP expression and its regulatory mechanisms in trophoblast cells throughout pregnancy. We emphasize its integral role in placental development and maternal-fetal interactions and delve into the correlations between YAP dysregulation and pregnancy complications. A nuanced understanding of YAP's functions during pregnancy could illuminate intricate molecular mechanisms and pave the way for innovative prevention and treatment strategies for pregnancy complications. Video Abstract.

Placental deficiency of the (pro)renin receptor ((P)RR) reduces placental development and functional capacity

The (pro)renin receptor ((P)RR; also known as ATP6AP2) is a multifunctional receptor. The (P)RR activates the tissue renin-angiotensin system (RAS) and is also involved in regulating integral intracellular pathways such as V-ATPase and Wnt/β-catenin signalling. Given this, the (P)RR may be associated with essential pathways in placentation, however its role within the context of pregnancy remains poorly characterised. The first trimester/extravillous trophoblast cell line, HTR-8/SVneo, underwent an siRNA knockdown where they were incubated for 24 h with a negative control siRNA or siRNA targeting ATP6AP2 mRNA. xCELLigence real-time cell analysis was performed to assess the effect of ATP6AP2 mRNA knockdown on HTR-8/SVneo cell proliferation, migration, and invasion. In subsequent experiments, GFP-encoding lentiviral packaged gene-constructs were used to knockdown (P)RR expression in the trophectoderm of C57/BL6/CBA-F1 mouse blastocysts. Blastocysts were incubated for 6 h with vehicle (no-virus), control virus (non-targeting shRNA and GFP), or (P)RR-knockdown virus ((P)RR shRNA and GFP) before transfer into recipient pseudo-pregnant Swiss CD1 female mice. Fetal and placental tissues were collected and assessed at embryonic age (EA) 10 and 18. (P)RR levels were measured in the labyrinth zone of day 18 placentae and stereological Merz grid analysis was performed to determine the volumetric distribution of trophoblasts, fetal capillaries, and the maternal blood space. We showed that a reduction of ATP6AP2 expression in HTR-8/SVneo cells in vitro, impaired trophoblast proliferation, migration, and invasion. In vivo, decreasing placental labyrinth (P)RR expression adversely effected placental physiology, decreasing placental trophoblast number and total surface area available for exchange, while also increasing maternal blood space. Additionally, decreased (P)RR affected placental efficacy evident by the reduced fetal-placental weight ratio. Our study shows that the (P)RR is necessary for appropriate placental development and function.

Toxicological mechanism of ammonia-N on haematopoiesis and apoptosis of haemocytes in Litopenaeus vannamei

Ammonia, as an important pollutant, contributed to the reduction of immunity, disruption of physiology in animals. RNA interference (RNAi) was performed to understand the function of astakine (AST) in haematopoiesis and apoptosis in Litopenaeus vannamei under ammonia-N exposure. Shrimps were exposed to 20 mg/L ammonia-N from 0 to 48 h with injection of 20 μg AST dsRNA. Further, shrimps were exposed to 0, 2, 10 and 20 mg/L ammonia-N also from 0 to 48 h. The results showed that the total haemocytes count (THC) decreased under ammonia-N stress and the knockdown of AST resulted in a further decrease of THC, suggesting that 1) the proliferation was decreased through the reduction of AST and Hedgehog, the differentiation was interfered by Wnt4, Wnt5 and Notch, and the migration was inhibited by the decrease of VEGF; 2) oxidative stress was induced under ammonia-N stress, leading to the increase of DNA damage with the up-regulated gene expression of death receptor, mitochondrial and endoplasmic reticulum stress pathways; 3) the changes of THC resulted from the decrease of proliferation, differentiation and migration of haematopoiesis cells and the increase of apoptosis of haemocytes. This study helps to deepen our understanding of risk management in shrimp aquaculture.

Polygenic prediction of preeclampsia and gestational hypertension

Preeclampsia and gestational hypertension are common pregnancy complications associated with adverse maternal and child outcomes. Current tools for prediction, prevention and treatment are limited. Here we tested the association of maternal DNA sequence variants with preeclampsia in 20,064 cases and 703,117 control individuals and with gestational hypertension in 11,027 cases and 412,788 control individuals across discovery and follow-up cohorts using multi-ancestry meta-analysis. Altogether, we identified 18 independent loci associated with preeclampsia/eclampsia and/or gestational hypertension, 12 of which are new (for example, MTHFR-CLCN6, WNT3A, NPR3, PGR and RGL3), including two loci (PLCE1 and FURIN) identified in the multitrait analysis. Identified loci highlight the role of natriuretic peptide signaling, angiogenesis, renal glomerular function, trophoblast development and immune dysregulation. We derived genome-wide polygenic risk scores that predicted preeclampsia/eclampsia and gestational hypertension in external cohorts, independent of clinical risk factors, and reclassified eligibility for low-dose aspirin to prevent preeclampsia. Collectively, these findings provide mechanistic insights into the hypertensive disorders of pregnancy and have the potential to advance pregnancy risk stratification.

MicroRNAs: key regulators of the trophoblast function in pregnancy disorders

The placenta is essential for a successful pregnancy and healthy intrauterine development in mammals. During human pregnancy, the growth and development of the placenta are inseparable from the rapid proliferation, invasion, and migration of trophoblast cells. Previous reports have shown that the occurrence of many pregnancy disorders may be closely related to the dysfunction of trophoblasts. However, the function regulation of human trophoblast cells in the placenta is poorly understood. Therefore, studying the factors that regulate the function of trophoblast cells is necessary. MicroRNAs (miRNAs) are small, non-coding, single-stranded RNA molecules. Increasing evidence suggests that miRNAs play a crucial role in regulating trophoblast functions. This review outlines the role of miRNAs in regulating the function of trophoblast cells and several common signaling pathways related to miRNA regulation in pregnancy disorders.

Long noncoding RNA maternally expressed gene 3 improves trophoblast dysfunction and inflammation in preeclampsia through the Wnt/β-Catenin/nod-like receptor pyrin domain-containing 3 axis

Inadequate trophoblastic infiltration and resulting placental hypoxia and inflammation comprise the core pathological basis of preeclampsia (PE). Maternally expressed gene 3 (MEG3) is known to be involved in the pathogenesis of preeclampsia by inhibiting the migration and invasion of trophoblasts and promoting their apoptosis. Nevertheless, the specific underlying downstream molecular mechanism of MEG3 is less well characterized. In this study, we detected lower expression levels of MEG3 and β-Catenin and higher expression of nod-like receptor pyrin domain-containing 3 (NLRP3) in placental tissues of pregnant women with severe preeclampsia (sPE) than in normal pregnancies. Elevated serum levels of IL-1β and TNF-α were also observed in the sPE group. Then, we established a hypoxia/reoxygenation (H/R) model to mimic preeclampsia. Similar results with sPE group were found in the H/R group compared with the control group. In addition, suppressive trophoblast proliferation, migration and invasion and increases in the apoptotic rate and inflammation were also detected in the H/R group. Notably, overexpressing MEG3 markedly improved trophoblast dysfunction and inflammation caused by H/R. However, the effects of MEG3 on trophoblasts, whether upregulated or downregulated, can be reversed by DKK-1 (Wnt/β-Catenin inhibitor) and MCC950 (NLRP3 inhibitor). The current study revealed that MEG3 regulates trophoblast function and inflammation through the Wnt/β-Catenin/NLRP3 axis and provided new insights into the pathogenesis of preeclampsia.

Transforming growth factor-β signaling governs the differentiation program of extravillous trophoblasts in the developing human placenta

Abnormal placentation has been noticed in a variety of pregnancy complications such as miscarriage, early-onset preeclampsia, and fetal growth restriction. Defects in the developmental program of extravillous trophoblasts (EVTs), migrating from placental anchoring villi into the maternal decidua and its vessels, is thought to be an underlying cause. Yet, key regulatory mechanisms controlling commitment and differentiation of the invasive trophoblast lineage remain largely elusive. Herein, comparative gene expression analyses of HLA-G-purified EVTs, isolated from donor-matched placenta, decidua, and trophoblast organoids (TB-ORGs), revealed biological processes and signaling pathways governing EVT development. In particular, bioinformatics analyses and manipulations in different versatile trophoblast cell models unraveled transforming growth factor-β (TGF-β) signaling as a crucial pathway driving differentiation of placental EVTs into decidual EVTs, the latter showing enrichment of a secretory gene signature. Removal of Wingless signaling and subsequent activation of the TGF-β pathway were required for the formation of human leukocyte antigen-G⁺ (HLA-G⁺) EVTs in TB-ORGs that resemble in situ EVTs at the level of global gene expression. Accordingly, TGF-β-treated EVTs secreted enzymes, such as DAO and PAPPA2, which were predominantly expressed by decidual EVTs. Their genes were controlled by EVT-specific induction and genomic binding of the TGF-β downstream effector SMAD3. In summary, TGF-β signaling plays a key role in human placental development governing the differentiation program of EVTs.

Transcription factor networks in trophoblast development

The placenta sustains embryonic development and is critical for a successful pregnancy outcome. It provides the site of exchange between the mother and the embryo, has immunological functions and is a vital endocrine organ. To perform these diverse roles, the placenta comprises highly specialized trophoblast cell types, including syncytiotrophoblast and extravillous trophoblast. The coordinated actions of transcription factors (TFs) regulate their emergence during development, subsequent specialization, and identity. These TFs integrate diverse signaling cues, form TF networks, associate with chromatin remodeling and modifying factors, and collectively determine the cell type-specific characteristics. Here, we summarize the general properties of TFs, provide an overview of TFs involved in the development and function of the human trophoblast, and address similarities and differences to their murine orthologs. In addition, we discuss how the recent establishment of human in vitro models combined with -omics approaches propel our knowledge and transform the human trophoblast field.

Wnt4, Wnt6 and β-catenin expression in human placental tissue - is there a link with first trimester miscarriage? Results from a pilot study

BACKGROUND

Demystifying the events around early pregnancy is challenging. A wide network of mediators and signaling cascades orchestrate the processes of implantation and trophoblast proliferation. Dysregulation of these pathways could be implicated in early pregnancy loss. There is accumulating evidence around the role of Wnt pathway in implantation and early pregnancy. The purpose of this study was to explore alterations in the expression of Wnt4, Wnt6 and β-catenin in placental tissue obtained from human first trimester euploid miscarriages versus normally developing early pregnancies.

METHODS

The study group consisted of first trimester miscarriages (early embryonic demises and incomplete miscarriages) and the control group of social terminations of pregnancy (TOPs). The placental mRNA expression of Wnt4, Wnt6 and β-catenin was studied using reverse transcription PCR and real time PCR. Only euploid conceptions were included in the analysis.

RESULTS

Wnt4 expression was significantly increased in placental tissue from first trimester miscarriages versus controls (p = 0.003). No significant difference was documented in the expression of Wnt6 (p = 0.286) and β-catenin (p = 0.793). There was a 5.1fold increase in Wnt4 expression for early embryonic demises versus TOPs and a 7.6fold increase for incomplete miscarriages versus TOPs - no significant difference between the two subgroups of miscarriage (p = 0.533).

CONCLUSIONS

This is, to our knowledge, the first study demonstrating significant alteration of Wnt4 expression in human placental tissue, from failed early pregnancies compared to normal controls. Undoubtedly, a more profound study is needed to confirm these preliminary findings and explore Wnt mediators as potential targets for strategies to predict and prevent miscarriage.

WNT and NOTCH signaling in human trophoblast development and differentiation

Correct development of the human placenta and its differentiated epithelial cells, syncytial trophoblasts (STBs) and extravillous trophoblasts (EVTs), is crucial for a successful pregnancy outcome. STBs develop by cell fusion of mononuclear cytotrophoblasts (CTBs) in placental floating villi, whereas migratory EVTs originate from specialized villi anchoring to the maternal decidua. Defects in trophoblast differentiation have been associated with severe pregnancy disorders such as early-onset preeclampsia and fetal growth restriction. However, the evolutionary pathways underlying normal and adverse placentation are poorly understood. Herein, we discuss Wingless (WNT) and NOTCH signaling, two pathways that play pivotal roles in human placenta and trophoblast development. Whereas WNT is necessary for expansion of trophoblast progenitors and stem cells, NOTCH1 is required for proliferation and survival of EVT precursors. Differentiation of the latter is orchestrated by a switch in NOTCH receptor expression as well as by changes in WNT ligands and their downstream effectors.

Roles of WNT6 in Sheep Endometrial Epithelial Cell Cycle Progression and Uterine Glands Organogenesis

The uterus, as part of the female reproductive tract, is essential for embryo survival and in the maintenance of multiple pregnancies in domestic animals. This study was conducted to investigate the effects of WNT6 on Hu sheep endometrial epithelial cells (EECs) and uterine glands (UGs) in Hu sheep, with high prolificacy rates. In the present study, Hu sheep with different fecundity, over three consecutive pregnancies, were divided into two groups: high prolificacy rate group (HP, litter size = 3) and low prolificacy rate group (LP, litter size = 1). A comparative analysis of the endometrial morphology was performed by immunofluorescence. RNA-seq was used to analyze the gene’s expression in endometrium of HP and LP Hu sheep, providing a candidate gene, which was investigated in EECs and organoid culture. Firstly, higher density of UGs was found in the HP Hu sheep groups (p < 0.05). The RNA-seq data revealed the importance of the WNT signaling pathway and WNT6 gene in Hu sheep endometrium. Functionally, WNT6 could promote the cell cycle progression of EECs via WNT/β-catenin signal and enhance UGs organogenesis. Taken together, WNT6 is a crucial regulator for sheep endometrial development; this finding may offer a new insight into understanding the regulatory mechanism of sheep prolificacy.

WNT3 hypomethylation counteracts low activity of the Wnt signaling pathway in the placenta of preeclampsia

Preeclampsia is a hypertensive disorder of pregnancy. Many studies have shown that epigenetic mechanisms may play a role in preeclampsia. Moreover, our previous study indicated that the differentially methylated genes in preeclampsia were enriched in the Wnt/β-catenin signaling pathway. This study aimed to identify differentially methylated Wnt/β-catenin signaling pathway genes in the preeclamptic placenta and to study the roles of these genes in trophoblast cells in vitro. Using an Illumina Infinium HumanMethylation 850 K BeadChip, we found that the Wnt signaling pathway was globally hypermethylated in the preeclamptic group compared with the term birth group, but hypomethylated in the preeclamptic group compared with the preterm birth group. Among all Wnt/β-catenin signaling pathway factors, WNT3 was the most significantly differentially expressed gene and was hypomethylated in the preeclamptic group compared to the nonhypertensive groups, namely, the preterm birth group and term birth group. This result was confirmed by pyrosequencing. Through quantitative real-time PCR and western blot analysis, the WNT3 gene was found to be highly expressed in preeclamptic placental tissues, in contrast to other WNT factors, which were previously reported to be expressed at low levels in placental tissues. Additionally, in the HTR8/SVneo cell line, knockdown of WNT3 suppressed the Wnt/β-catenin signaling pathway, consistent with the findings for other WNT factors. These results prompted us to speculate that the WNT3 gene counteracts the low activation state of the Wnt signaling pathway in the preeclamptic placenta through methylation modification.

Low Abundance Fusobacterium Nucleatum Supports Early Pregnancy Development - An In Vitro Study

Pregnancy success depends greatly on a balanced immune homeostasis. The detection of bacterial components in the upper reproductive tract in non-pregnant and pregnant women raised questions on its possible beneficial role in reproductive health. The local conditions that allow the presence of bacteria to harmonize with the establishment of pregnancy are still unknown. Among the described bacterial species in endometrial and placental samples, Fusobacterium nucleatum was found. It has been observed that F. nucleatum can induce tumorigenesis in colon carcinoma, a process that shares several features with embryo implantation. We propose that low concentrations of F. nucleatum may improve trophoblast function without exerting destructive responses. Inactivated F. nucleatum and E. coli were incubated with the trophoblastic cell lines HTR8/SVneo, BeWo, and JEG-3. Viability, proliferation, migratory capacity, invasiveness and the secretion of chemokines, other cytokines and matrix metalloproteinases were assessed. The presence of F. nucleatum significantly induced HTR8/SVneo invasion, accompanied by the secretion of soluble mediators (CXCL1, IL-6 and IL-8) and metalloproteinases (MMP-2 and MMP-9). However, as concentrations of F. nucleatum increased, these did not improve invasiveness, hindered migration, reduced cell viability and induced alterations in the cell cycle. Part of the F. nucleatum effects on cytokine release were reverted with the addition of a TLR4 blocking antibody. Other effects correlated with the level of expression of E-cadherin on the different cell lines tested. Low amounts of F. nucleatum promote invasion of HTR8/SVneo cells and induce the secretion of important mediators for pregnancy establishment. Some effects were independent of LPS and correlated with the expression of E-cadherin on trophoblasts.

Small extracellular vesicles derived from in vivo- or in vitro-produced bovine blastocysts have different miRNAs profiles-Implications for embryo-maternal recognition

In vivo- and in vitro-produced bovine embryos have different metabolic profiles and differences in gene transcription patterns. These embryos also have a distinct ability to establish and sustain early pregnancies. Small extracellular vesicles (sEVs) are secreted by embryos and carry bioactive molecules, such as miRNAs. We hypothesize that in vivo or in vitro-produced bovine hatched blastocysts on Day 9 and the sEVs secreted by them have different miRNA profiles. To address this hypothesis, embryos of both groups were placed in in vitro culture on Day 7. After 48 h, hatched embryos and hatched embryo-conditioned media (eCM) of both groups were collected. A total of 210 miRNAs were detected in embryos of both groups, of these 6 miRNAs were downregulated, while 7 miRNAs were upregulated in vitro group when compared to in vivo group. sEVs were isolated from eCM to determine miRNA profile. A total of 106 miRNAs were detected in both groups, including 14 miRNAs upregulated in sEVs from in vivo-eCM, and 2 miRNAs upregulated in sEVs from in vitro-eCM. These miRNAs express in embryos and sEVs secreted by them regulate early embryonic developmental and endometrial pathways, which can modify embryo-maternal communication during early pregnancy and consequently affect pregnancy establishment.

Elevated Serum SFRP5 Levels During Preeclampsia and Its Potential Association with Trophoblast Dysfunction via Wnt/β-Catenin Suppression

Preeclampsia (PE) is a life-threatening pregnancy complication associated with diminished trophoblast migration and invasion. Wnt signalling is one of the most important regulators of placentation. Secreted frizzled-related protein 5 (SFRP5) is an anti-inflammatory adipokine that may inhibit Wnt signalling. In this study, we aimed to investigate the relationship between SFRP5 and PE and its effect on trophoblast function, as well as the underlying signalling pathways. SFRP5 levels in the serum and placental tissues were detected using enzyme-linked immunosorbent assay and immunohistochemistry, respectively. To evaluate the effect of SFRP5 on Wnt signalling, the human trophoblast cell line HTR8/SVneo was treated with recombinant human SFRP5 and Dickkopf-related protein 1 (Dkk-1, canonical Wnt inhibitor) proteins and lithium chloride (LiCl, canonical Wnt agonist). The migration and invasion ability of HTR8/SVneo cells was evaluated using wound-healing and Matrigel Transwell assays. The activities of multiple matrix metalloproteinases (MMP)-2/9 were detected using gelatin zymography. Expression of glycogen synthase kinase-3 beta (GSK3β) and β-catenin proteins was investigated using western blotting. The serum SFRP5 levels were elevated in patients with PE, but SFRP5 expression was not detected in the placental tissues. Furthermore, SFRP5 inhibited the migration and invasion of HTR8/SVneo cells in vitro, increased GSK3β, and decreased β-catenin expression and MMP-2/9 activity in HTR8/SVneo cells. In conclusion, this study suggests that SFRP5 inhibits trophoblast migration and invasion potentially via the inhibition of Wnt/β-catenin signalling, which might be involved in the development of PE. However, the primary cause of the increased SFRP5 levels needs to be investigated.

Placental Angiogenesis in Mammals: A Review of the Regulatory Effects of Signaling Pathways and Functional Nutrients

Normal placental development and proper angiogenesis are essential for fetal growth during pregnancy. Angiogenesis involves the regulatory action of many angiogenic factors and a series of signal transduction processes inside and outside the cell. The obstruction of placental angiogenesis causes fetal growth restriction and serious pregnancy complications, even leading to fetal loss and pregnancy cessation. In this review, the effects of placental angiogenesis on fetal development are described, and several signaling pathways related to placental angiogenesis and their key regulatory mediators are summarized. These factors, which include vascular endothelial growth factor (VEGF)-VEGF receptor, delta-like ligand 4 (DLL-4)-Notch, Wnt, and Hedgehog, may affect the placental angiogenesis process. Moreover, the degree of vascularization depends on cell proliferation, migration, and differentiation, which is affected by the synthesis and secretion of metabolites or intermediates and mutual coordination or inhibition in these pathways. Furthermore, we discuss recent advances regarding the role of functional nutrients (including amino acids and fatty acids) in regulating placental angiogenesis. Understanding the specific mechanism of placental angiogenesis and its influence on fetal development may facilitate the establishment of new therapeutic strategies for the treatment of preterm birth, pre-eclampsia, or intrauterine growth restriction, and provide a theoretical basis for formulating nutritional regulation strategies during pregnancy.

RNA-Seq reveals changes in human placental metabolism, transport and endocrinology across the first-second trimester transition

The human placenta is exposed to major environmental changes towards the end of the first trimester associated with full onset of the maternal arterial placental circulation. Changes include a switch from histotrophic to hemotrophic nutrition, and a threefold rise in the intraplacental oxygen concentration. We evaluated their impact on trophoblast development and function using RNA-sequencing (RNA-Seq) and DNA-methylation analyses performed on the same chorionic villous samples at 7-8 (n=8) and 13-14 (n=6) weeks of gestation. Reads were adjusted for fetal sex. Most DEGs were associated with protein processing in the endoplasmic reticulum (ER), hormone secretion, transport, extracellular matrix, vasculogenesis, and reactive oxygen species metabolism. Transcripts higher in the first trimester were associated with synthesis and ER processing of peptide hormones, and glycolytic pathways. Transcripts encoding proteins mediating transport of oxygen, lipids, protein, glucose, and ions were significantly increased in the second trimester. The motifs of CBX3 and BCL6 were significantly overrepresented, indicating the involvement of these transcription factor networks in the regulation of trophoblast migration, proliferation and fusion. These findings are consistent with a high level of cell proliferation and hormone secretion by the early placenta to secure implantation in a physiological low-oxygen environment.

CTHRC1 promotes growth, migration and invasion of trophoblasts via reciprocal Wnt/β-catenin regulation

Preeclampsia (PE) is a pregnancy complication that is characterized by high blood pressure and is associated with high maternal and fetal morbidities. At a mechanistic level, PE is characterized by reduced invasion ability of trophoblasts. Collagen triple helix repeat containing-1 (CTHRC1) is a well-known tumor-promoting factor in several malignant tumors, but its role in trophoblasts remains unknown. In this study, we characterized the expression of CTHRC1 in placenta tissue samples from PE pregnancies and from normal pregnancies. We used the trophoblasts cell lines HTR-8/SVneo and JEG-3 to investigate the role of CTHRC1 in cell migration, invasion and proliferation. Western blot, PCR and TOP/FOP luciferase activity assays were used to investigate the molecular mechanisms underlying these cell behaviors. Placenta tissue samples obtained from pregnant women with PE expressed lower levels of CTHRC1 than those of placenta tissues from women with normal pregnancies. Down-regulation of CTHRC1 impaired cell proliferation, migration and invasion of trophoblasts, while CTHRC1 overexpression promoted nuclear translocation of β-catenin, a result that was further confirmed by TOP/FOP luciferase activity assay. Our findings suggest that CTHRC1 promotes migration and invasion of trophoblasts via reciprocal Wnt/β-catenin signaling pathway. Down-regulation of CTHRC1 may be a potential mechanism underpinning the development of preeclampsia.

The (pro)renin receptor ((P)RR) and soluble (pro)renin receptor (s(P)RR) in pregnancy

The (pro)renin receptor ((P)RR) is a multi-functional protein that can be proteolytically cleaved and released in a soluble form (s(P)RR). Recently, the (P)RR and s(P)RR have become of interest in pregnancy and its associated pathologies. This is because the (P)RR not only activates tissue renin angiotensin systems, but it is also an integral component of vacuolar-ATPase, activates the wingless/integrated (Wnt)/β-catenin and extracellular signal regulated kinases 1 and 2/mitogen-activated protein kinase signalling pathways, and stabilises the β subunit of pyruvate dehydrogenase. Additionally, s(P)RR is detected in plasma and urine, and maternal plasma levels are elevated in pregnancy complications including fetal growth restriction, preeclampsia and gestational diabetes mellitus. Therefore, s(P)RR has potential as a biomarker for these pregnancy pathologies. Preliminary functional findings suggest that s(P)RR may be important for regulating fluid balance, inflammation and blood pressure, all of which contribute to a successful pregnancy. The (P)RR and s(P)RR regulate pathways that are known to be important in maintaining pregnancy, however their role in the physiological context of pregnancy is poorly characterised. This review summarises the known and potential functions of the (P)RR and s(P)RR in pregnancy, and how their dysregulation may contribute to pregnancy complications. It also highlights the need for further research into the source and function of s(P)RR in pregnancy. Soluble (P)RR levels could be indicative of placental, kidney or liver dysfunction and therefore be a novel clinical biomarker, or therapeutic target, to improve the detection and treatment of pregnancy pathologies.

Long noncoding RNA expression profiling identifies MIR210HG as a novel molecule in severe preeclampsia

OBJECTIVE

Preeclampsia (PE) is a potentially fatal pregnancy-specific complication. Nevertheless, the pathogenesis of PE remains indistinct. Recently, increasing studies emphasized that long noncoding RNAs (lncRNAs) functions as imperative regulators in PE. The aim of this study was to compare the lncRNAs transcript profile of placentae in early onset severe preeclampsia (EOSP) with lncRNAs in normal pregnancy (NP) and to evaluate the role of lncRNA MIR210HG (microRNA 210 host gene) in the PE pathogenesis.

METHODS

Using RNA sequencing, we compared transcriptome profiles of placentae in EOSP (n = 3) and NP (n = 3). Bioinformatic tools were used to predict the function of differentially expressed genes while qRT-PCR was used to verify RNA sequencing data. The role of MIR210HG in HTR8/SVneo migration and invasion were analyzed by in vitro MIR210HG gene overexpression.

RESULTS

Our results showed that 527 lncRNAs and 600 mRNAs were differentially expressed in placental samples of EOSP, and the analysis identified 63 key EOSP related genes. As indicated by bioinformatics analyses, lncRNA MIR210HG was a potential pathogenic marker of PE. LncRNA-MIR210HG expression was upregulated in placental samples of PE and enriched in the canonical Wnt signalling pathway. MiR210HG overexpression inhibited HTR8/SVneo cell migration and invasion in vitro. Additionally, miR210HG upregulated dickkopf-1 expression via the sponging of microRNA-520a-3p (miR-520a-3p), thus repressing trophoblast migration and invasion.

CONCLUSION

Our study showed that MiR210HG is a novel upregulated lncRNA in the placentas of PE and MiR210HG regulates the migration and invasive potential of HTR-8/SVneo cell by targeting the miR-520a-3p/Dickkopf-1 axis.

PAR1&2 driven placenta EVT invasion act via LRP5/6 as coreceptors

While the involvement of protease-activated receptors (PARs) in the physiological regulation of human placenta development, as in tumor biology, is recognized, the molecular pathway is unknown. We evaluated the impact of PAR₁ and PAR₂ function in cytotrophoblast (CTB) proliferation and invasion in a system of extravillous trophoblast (EVT) organ culture and in human cell-lines. Activation of PAR₁ - and PAR₂ -induced EVT invasion and proliferation, while the shRNA silencing of low-density lipoprotein receptor-related protein 5/6 (LRP5/6) inhibited these processes. PAR₁ and PAR₂ effectively induce β-catenin stabilization in a manner similar to that shown for the canonical β-catenin stabilization pathway yet independent of Wnts. Immunoprecipitation analyses and protein-protein docking demonstrated the co-association between either PAR₁ or PAR₂ with LRP5/6 forming an axis of PAR-LRP5/6-Axin. Noticeably, in PAR₁ -PAR₂ heterodimers a dominant role is assigned to PAR₂ over PAR₁ as shown by inhibition of PAR₁ -induced β-catenin levels, and Dvl nuclear localization. This inhibition takes place either by shRNA silenced hPar2 or in the presence of a TrPAR₂ devoid its cytoplasmic tail. Indeed, TrPAR₂ cannot form the PAR₁ -PAR₂ complex, obstructing thereby the flow of signals downstream. Elucidation of the mechanism of PAR-induced invasion contributes to therapeutic options highlighting key partners in the process.

Hyperactivated Wnt-β-catenin signaling in the absence of sFRP1 and sFRP5 disrupts trophoblast differentiation through repression of Ascl2

Background

Wnt signaling is a critical determinant for the maintenance and differentiation of stem/progenitor cells, including trophoblast stem cells during placental development. Hyperactivation of Wnt signaling has been shown to be associated with human trophoblast diseases. However, little is known about the impact and underlying mechanisms of excessive Wnt signaling during placental trophoblast development.

Results

In the present work, we observed that two inhibitors of Wnt signaling, secreted frizzled-related proteins 1 and 5 (Sfrp1 and Sfrp5), are highly expressed in the extraembryonic trophoblast suggesting possible roles in early placental development. Sfrp1 and Sfrp5 double knockout mice exhibited disturbed trophoblast differentiation in the placental ectoplacental cone (EPC), which contains the precursors of trophoblast giant cells (TGCs) and spongiotrophoblast cells. In addition, we employed mouse models expressing a truncated β-catenin with exon 3 deletion globally and trophoblast-specifically, as well as trophoblast stem cell lines, and unraveled that hyperactivation of canonical Wnt pathway exhausted the trophoblast precursor cells in the EPC, resulting in the overabundance of giant cells at the expense of spongiotrophoblast cells. Further examination uncovered that hyperactivation of canonical Wnt pathway disturbed trophoblast differentiation in the EPC via repressing Ascl2 expression.

Conclusions

Our investigations provide new insights that the homeostasis of canonical Wnt-β-catenin signaling is essential for EPC trophoblast differentiation during placental development, which is of high clinical relevance, since aberrant Wnt signaling is often associated with trophoblast-related diseases.

Macrophage-stimulating protein is decreased in severe preeclampsia and regulates the biological behavior of HTR-8/SVneo trophoblast cells

Preeclampsia (PE) is a major challenge for obstetricians. There is no effective way to block the development of PE other than terminating the pregnancy. The biological behavior of trophoblast cells, which are similar to cancer cells, may be closely related to the onset of PE. The vital role of macrophage-stimulating protein (MSP) in the development and progression of cancer has been recognized, while a role for this protein in PE has rarely been reported. This study aimed to explore whether MSP affects severe PE (sPE) and, if so, to characterize the mechanism. Patient information, blood samples and/or placental tissues were collected. An enzyme-linked immunosorbent assay (ELISA) was used to determine the plasma MSP concentration. The relationships between the plasma MSP concentration and clinical characteristics were analyzed. Immunofluorescence was performed to localize MSP in placental tissues. Western blotting and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were used to determine MSP protein and mRNA expression in placental tissues. MSP was overexpressed or underexpressed in the trophoblastic cell line HTR-8/SVneo by lentiviral transfection and the proliferation, apoptosis, migration, invasion and angiogenesis of cells were detected. MSP was downregulated in sPE, and the underexpression of MSP inhibited HTR-8/SVneo cell proliferation, migration, invasion and angiogenesis. We further verified that MSP affects the biological behavior of trophoblast cells through the β-catenin/ZEB1 signaling pathway. These results suggest that decreased MSP in the blood and placental tissues of patients with sPE, especially those with early-onset sPE, leads to reduced trophoblast cell invasion, which plays an important role in the pathogenesis of PE.

Pivotal role of the transcriptional co-activator YAP in trophoblast stemness of the developing human placenta

Various pregnancy complications, such as severe forms of preeclampsia or intrauterine growth restriction, are thought to arise from failures in the differentiation of human placental trophoblasts. Progenitors of the latter either develop into invasive extravillous trophoblasts, remodeling the uterine vasculature, or fuse into multinuclear syncytiotrophoblasts transporting oxygen and nutrients to the growing fetus. However, key regulatory factors controlling trophoblast self-renewal and differentiation have been poorly elucidated. Using primary cells, three-dimensional organoids, and CRISPR-Cas9 genome-edited JEG-3 clones, we herein show that YAP, the transcriptional coactivator of the Hippo signaling pathway, promotes maintenance of cytotrophoblast progenitors by different genomic mechanisms. Genetic or chemical manipulation of YAP in these cellular models revealed that it stimulates proliferation and expression of cell cycle regulators and stemness-associated genes, but inhibits cell fusion and production of syncytiotrophoblast (STB)-specific proteins, such as hCG and GDF15. Genome-wide comparisons of primary villous cytotrophoblasts overexpressing constitutively active YAP-5SA with YAP KO cells and syncytializing trophoblasts revealed common target genes involved in trophoblast stemness and differentiation. ChIP-qPCR unraveled that YAP-5SA overexpression increased binding of YAP-TEAD4 complexes to promoters of proliferation-associated genes such as CCNA and CDK6 Moreover, repressive YAP-TEAD4 complexes containing the histone methyltransferase EZH2 were detected in the genomic regions of the STB-specific CGB5 and CGB7 genes. In summary, YAP plays a pivotal role in the maintenance of the human placental trophoblast epithelium. Besides activating stemness factors, it also directly represses genes promoting trophoblast cell fusion.

In-vitro investigation of calcitonin associated effects on the trophoblastic cells

Calcitonin is expressed in the epithelium of endometrium, and modulates zonula adherens junctions which are composed of cadherin-catenins complex during the implantation window. Trophoblastic cells which have complex interaction with the epithelial cells of endometrium during implantation were demonstrated to have calcitonin receptors. Mechanism of action of calcitonin on trophoblastic cells has not yet been elucidated. Therefore, it was aimed to determine the effects of calcitonin on the expressions of β-catenin and phospho-β-catenin in a dose depended manner under the influence of progesterone and estrogen hormones (P + E) by using JAR cell line through the immunocytochemical and Western blot analyses. Moreover, adherens junctions (AJs) were ultrastructurally investigated to assess the involvement of cadherin-catenin complex in accordance with the changes in the specified parameters. Immunocytochemical analysis showed that only 10 nM calcitonin treated group had increased expression of membranous β-catenin compared to the control group, while there was decreased expression of β-catenin in the nucleus of all the experimental groups. Cytoplasmic expressions of the phospho-β-catenin decreased in all experimental groups compared to the control group while the decrease in the nuclear expression was remarkable in the groups treated with P + E, and P + E + 250 nM calcitonin. Western blot analysis showed that total β-catenin and phospho-β-catenin expressions were not significantly different. Ultrastructural analysis showed that increase in the number of AJs was noticeable in the group treated with 10 nM calcitonin. Overall, the localization and expression levels of β-catenin and phospho-β-catenin suggest that calcitonin could show its effects through the non-canonical pathway in the trophoblastic cells.

Extravillous trophoblast invasion accelerated by WNT3A, 5A, and 10B via CD44

INTRODUCTION

Appropriate extravillous trophoblast (EVT) invasion is essential for successful pregnancy. Previously, we showed that EVTs express CD44, which accelerated EVT invasion. However, its regulation mechanism via CD44 remains unknown. Our hypothesis was that WNT signaling enhanced EVT invasion via CD44. To test this hypothesis, we investigated the effects of WNT ligands on CD44 expression and EVT invasion using EVT cell lines and isolated primary EVTs.

METHODS

We used EVT cell lines (HTR8/SVneo and HChEpC1b) and isolated primary EVTs, extracted from first-trimester trophoblasts. The cells were supplemented with WNT3A, 5A, and 10B. We examined cell invasion and the expressions of CD44 and matrix metalloproteinase (MMP) 9. Next, to clarify the pathway of WNT10B in EVTs, we knock-downed WNT10B using siRNA and activated or inhibited the WNT canonical pathway using an activator (lithium chloride) or inhibitor (FH535, XAV939) with WNT10B addition.

RESULTS

WNT3A, 5A, and 10B accelerated the invasion in the EVT lines and isolated primary EVTs. The expressions of CD44 and MMP9 were also upregulated by WNT ligands. WNT10B knockdown significantly inhibited EVT invasion concomitantly with CD44 expression. The WNT canonical pathway activator upregulated CD44 expression and its inhibitor downregulated it with WNT10B addition.

CONCLUSIONS

The present study is the first to show the possibility that WNT3A, WNT5A, and WNT10B exist upstream of CD44 in EVTs. Among them, WNT10B may be a novel accelerator of EVT invasion. WNT signaling mediated by multiple WNT ligands may contribute to EVT invasion.

MicroRNAs in Uteroplacental Vascular Dysfunction

Pregnancy complications of preeclampsia and intrauterine growth restriction (IUGR) are major causes of maternal and perinatal/neonatal morbidity and mortality. Although their etiologies remain elusive, it is generally accepted that they are secondary to placental insufficiency conferred by both failure in spiral artery remodeling and uteroplacental vascular malfunction. MicroRNAs (miRNAs) are small no-coding RNA molecules that regulate gene expression at the post-transcriptional level. Increasing evidence suggests that miRNAs participate in virtually all biological processes and are involved in numerous human diseases. Differentially expressed miRNAs in the placenta are typical features of both preeclampsia and IUGR. Dysregulated miRNAs target genes of various signaling pathways in uteroplacental tissues, contributing to the development of both complications. In this review, we provide an overview of how aberrant miRNA expression in preeclampsia and IUGR impacts the expression of genes involved in trophoblast invasion and uteroplacental vascular adaptation.

LRP6 regulates Rab7-mediated autophagy through the Wnt/β-catenin pathway to modulate trophoblast cell migration and invasion

Pre-eclampsia is a common complication during pregnancy; however, the underlying mechanisms of the crosstalk between low-density lipoprotein receptor-related protein 6 (LRP6) and autophagy in trophoblast cells are still not fully explored. Messenger RNA (mRNA) and protein levels of LRP6, beclin 1, Unc-51-like autophagy activating kinase 1 (ULK1), p62, vimentin, matrix metallopeptidase-9 (MMP-9), β-catenin, c-Myc, and Rab7, as well as the ratio of LC3-II/LC3-I, were analysed by quantitative real-time polymerase chain reaction or Western blot analysis, respectively. An MTT assay was used to measure cell growth, and transwell and wound healing assays were carried out to evaluate the invasion and migration abilities of the trophoblasts used. An immunofluorescence assay was used to measure LC3. The mRFP-GFP-LC3 tandem fluorescence assay was applied to detect autophagic flow. LRP6 overexpression was achieved by constructing pcDNA3.1-LRP6 vectors. LRP6 was expressed at low levels in HTR-8/SVneo cells under hypoxia/reoxygenation (H/R) conditions. H/R inhibited the activation of autophagy. LRP6 overexpression promoted cell proliferation and activated autophagy, which led to the upregulation of beclin 1 and ULK1, as well as the ratio of LC3-II/LC3-I and the downregulation of p62. Furthermore, LRP6 overexpression elevated the migration and invasion abilities of the indicated cells and increased vimentin and MMP-9 expression levels. Furthermore, LRP6 upregulated Rab7 and activated autophagy through the Wnt/β-catenin pathway. The late autophagy inhibitor bafilomycin A1 (Baf-A1) and the Wnt/β-catenin pathway inhibitor PKF115-584 reversed the effects of LRP6 on trophoblast autophagy, migration and invasion. LRP6 promotes Rab7-mediated autophagy by activating the Wnt/β-catenin pathway, which leads to increasing migration and invasion of trophoblast cells. Our study paves a new avenue for clinical treatment, and LRP6 may serve as an essential target in pre-eclampsia.

Human placenta and trophoblast development: key molecular mechanisms and model systems

Abnormal placentation is considered as an underlying cause of various pregnancy complications such as miscarriage, preeclampsia and intrauterine growth restriction, the latter increasing the risk for the development of severe disorders in later life such as cardiovascular disease and type 2 diabetes. Despite their importance, the molecular mechanisms governing human placental formation and trophoblast cell lineage specification and differentiation have been poorly unravelled, mostly due to the lack of appropriate cellular model systems. However, over the past few years major progress has been made by establishing self-renewing human trophoblast stem cells and 3-dimensional organoids from human blastocysts and early placental tissues opening the path for detailed molecular investigations. Herein, we summarize the present knowledge about human placental development, its stem cells, progenitors and differentiated cell types in the trophoblast epithelium and the villous core. Anatomy of the early placenta, current model systems, and critical key regulatory factors and signalling cascades governing placentation will be elucidated. In this context, we will discuss the role of the developmental pathways Wingless and Notch, controlling trophoblast stemness/differentiation and formation of invasive trophoblast progenitors, respectively.

β-catenin/LIN28B promotes the proliferation of human choriocarcinoma cells via Let-7a repression

Choriocarcinoma is a rare and malignant trophoblastic tumor. However, the molecular mechanisms by which choriocarcinoma is regulated remain unknown. In the present study, we first elucidated that LIN28B was highly expressed in human choriocarcinoma tissues and choriocarcinoma cell lines. Our data further demonstrated that knockdown of LIN28B by small interfering RNA caused an increase in Let-7a expression in JAR cells. In addition, silencing of LIN28B inhibited IGF2BP1 expression and suppressed cell proliferation capacity, both of which can be markedly restored by Let-7a inhibitor. In contrast, LIN28B over-expression-improved cell proliferation was inhibited by Let-7a mimic. Knockdown of β-catenin resulted in reduced expression of LIN28B and increased expression of Let-7a. Knockdown of β-catenin also caused a decrease in cell proliferation, which can be recovered by re-expression of LIN28B or by Let-7a inhibitor. Collectively, our data indicate that β-catenin/LIN28B/Let-7a pathway may be crucial for the regulation of cell proliferation in human choriocarcinoma cells.

Regulation of Placental Extravillous Trophoblasts by the Maternal Uterine Environment

During placentation invasive extravillous trophoblasts (EVTs) migrate into the maternal uterus and modify its vessels. In particular, remodeling of the spiral arteries by EVTs is critical for adapting blood flow and nutrient transport to the developing fetus. Failures in this process have been noticed in different pregnancy complications such as preeclampsia, intrauterine growth restriction, stillbirth, or recurrent abortion. Upon invasion into the decidua, the endometrium of pregnancy, EVTs encounter different maternal cell types such as decidual macrophages, uterine NK (uNK) cells and stromal cells expressing a plethora of growth factors and cytokines. Here, we will summarize development of the EVT lineage, a process occurring independently of the uterine environment, and formation of its different subtypes. Further, we will discuss interactions of EVTs with arteries, veins and lymphatics and illustrate how the decidua and its different immune cells regulate EVT differentiation, invasion and survival. The present literature suggests that the decidual environment and its soluble factors critically modulate EVT function and reproductive success.

MicroRNA-590-3p inhibits trophoblast-dependent maternal spiral artery remodeling by repressing low-density lipoprotein receptor-related protein 6

Background

The remodeling of maternal spiral artery following embryo implantation, which relies on well‐regulated trophoblast functions, is a pivotal process to ensure a successful pregnancy. Low‐density lipoprotein receptor‐related protein 6 (LRP6) and microRNAs (miRNAs, miRs) are suggested to be involved in angiogenesis and several vascular diseases; however, their functions in the control of trophoblast remain elusive. We therefore aimed to examine the roles of LRP6 and miR‐590‐3p in the regulation of trophoblast during the remodeling of maternal spiral artery.

Methods

HTR‐8/SVneo cell, a trophoblast cell line, was utilized to study the effects of LRP6 and miR‐590‐3p on apoptosis, cell proliferation, migration, invasion, as well as tube formation. Expression of angiogenic factors placental growth factor (PlGF), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), and activities of canonical Wnt/β‐catenin signaling pathway, which were implicated in the process of artery remodeling, were also examined.

Results

MiR‐590‐3p directly targeted 3′ untranslated region (3′‐UTR) of LRP6 mRNA and repressed LRP6 expression, which in turn inhibited proliferation, migration, invasion, as well as tube formation, and resulted in apoptosis in HTR‐8/SVneo cells. Further, inhibition of LRP6 through miR‐590‐3p significantly suppressed the expression of PlGF, MMPs, and VEGF and reduced the activation of Wnt/β‐catenin signaling pathway.

Conclusion

MicroRNAs‐590‐3p may inhibit trophoblast‐dependent maternal spiral artery remodeling, via both trophoblast invasion and endovascular formation, by repressing LRP6.

Inside the Endometrial Cell Signaling Subway: Mind the Gap(s)

Endometrial cells perceive and respond to their microenvironment forming the basis of endometrial homeostasis. Errors in endometrial cell signaling are responsible for a wide spectrum of endometrial pathologies ranging from infertility to cancer. Intensive research over the years has been decoding the sophisticated molecular means by which endometrial cells communicate to each other and with the embryo. The objective of this review is to provide the scientific community with the first overview of key endometrial cell signaling pathways operating throughout the menstrual cycle. On this basis, a comprehensive and critical assessment of the literature was performed to provide the tools for the authorship of this narrative review summarizing the pivotal components and signaling cascades operating during seven endometrial cell fate “routes”: proliferation, decidualization, implantation, migration, breakdown, regeneration, and angiogenesis. Albeit schematically presented as separate transit routes in a subway network and narrated in a distinct fashion, the majority of the time these routes overlap or occur simultaneously within endometrial cells. This review facilitates identification of novel trajectories of research in endometrial cellular communication and signaling. The meticulous study of endometrial signaling pathways potentiates both the discovery of novel therapeutic targets to tackle disease and vanguard fertility approaches.

Self-Renewing Trophoblast Organoids Recapitulate the Developmental Program of the Early Human Placenta

Defective placentation is the underlying cause of various pregnancy complications, such as severe intrauterine growth restriction and preeclampsia. However, studies on human placental development are hampered by the lack of a self-renewing in vitro model that would recapitulate formation of trophoblast progenitors and differentiated subtypes, syncytiotrophoblast (STB) and invasive extravillous trophoblast (EVT), in a 3D orientation. Hence, we established long-term expanding organoid cultures from purified first-trimester cytotrophoblasts (CTBs). Molecular analyses revealed that the CTB organoid cultures (CTB-ORGs) express markers of trophoblast stemness and proliferation and are highly similar to primary CTBs at the level of global gene expression. Whereas CTB-ORGs spontaneously generated STBs, withdrawal of factors for self-renewal induced trophoblast outgrowth, expressing the EVT progenitor marker NOTCH1, and provoked formation of adjacent, distally located HLA-G⁺ EVTs. In summary, we established human CTB-ORGs that grow and differentiate under defined culture conditions, allowing future human placental disease modeling.

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Derivation of cytotrophoblast organoids from human placenta

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Long-term expansion of trophoblast organoids in a chemically defined medium

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Formation of the extravillous trophoblast lineage under defined culture conditions

SFRP3 negatively regulates placental extravillous trophoblast cell migration mediated by the GCM1-WNT10B-FZD7 axis

Migration of placental extravillous trophoblast (EVT) cells into uterine decidua facilitates the establishment of blood circulation between mother and fetus and is modulated by EVT-decidual cell interaction. Poor or excessive EVT migration is associated with pregnancy complications such as preeclampsia or placenta accreta. Glial cells missing 1 (GCM1) transcription factor is essential for placental development, and decreased GCM1 activity is detected in preeclampsia. To study whether GCM1 regulates trophoblast cell migration, here we showed that GCM1 promotes BeWo and JAR trophoblast cell migration through a novel target gene, WNT10B. Moreover, WNT10B signaling stimulated cytoskeletal remodeling via Rac1 and frizzled 7 (FZD7) was identified as the cognate receptor for WNT10B to up-regulate cell migration. We further showed that secreted frizzled-related protein 3 (SFRP3) is expressed in uterine decidual cells by immunohistochemistry and that SFRP3 expression in telomerase-transformed human endometrial stromal cells (T-HESCs) is elevated under decidualization stimuli and further enhanced by bone morphogenetic protein 2 via SMAD1. SFRP3 blocked the interaction between FZD7 and WNT10B to decrease BeWo cell migration, which corroborated the elevated BeWo cell migration when cocultured with decidualized and SFRP3-knockdown T-HESC monolayer. Our results suggest that GCM1 up-regulates EVT cell migration through WNT10B and FZD7, which is negatively modulated by decidual SFRP3.-Wang, L.-J., Lo, H.-F., Lin, C.-F., Ng, P.-S., Wu, Y.-H., Lee, Y.-S., Cheong, M.-L., Chen, H. SFRP3 negatively regulates placental extravillous trophoblast cell migration mediated by the GCM1-WNT10B-FZD7 axis.

Knockdown of Uba2 inhibits colorectal cancer cell invasion and migration through downregulation of the Wnt/β-catenin signaling pathway

Colorectal cancer is a serious threat to human health, and has a high mortality rate. There is currently no effective therapy for end-stage colorectal cancer. In recent years, molecular targeted therapy has received increasing attention for cancer treatment. In particular, the role of Uba2, a vital component of SUMO-activating enzyme, has been highlighted, which plays important roles in the progression of certain cancers; however, its role in colorectal cancer remains unclear. Accordingly, the aim of this study was to evaluate the relationship between Uba2 and colorectal cancer. Uba2 expression was knocked down in two colorectal cancer cell lines, and gene microarray analysis was conducted, followed by proliferation, migration, and invasion assays. Uba2 knockdown influenced the expression of several genes, and significantly inhibited the proliferation, migration, and invasion of cancer cells. To determine the underlying mechanism, the expression of related signaling pathways and molecules was evaluated in the knockdown cell lines. Overall, the results suggest that Uba2 participates in the progression, invasion, and metastasis of colorectal cancer, and the possible mechanism is via regulating the Wnt signaling pathway and enhancing epithelial-mesenchymal transition behaviors of colorectal cancer cells. Therefore, Uba2 is expected to be an important oncoprotein and potential therapeutic target in colorectal cancer.

New Polymorphic Changes in the Wnt7A Gene and Their Effect on Reproductive Traits in Pigs

For many years, research has been undertaken to identify genetic markers associated with reproductive traits in pigs, but these issues are still open to research. WNT7A expression was found in endometrium during embryo implantation as well as in early pregnancy in humans and in different species of animals. Our study was designed to identify polymorphic changes in the WNT7A gene and their effect on reproductive traits in 480 Polish Large White (PLW ) and Polish Landrace (PL) pigs in 4 successive litters. As a result, 3 mutations were identified: two transitions in exon 3 g.6270G>A (rs326274214) and in intron 4 g.36251G>A (rs321204163) and deletion/insertion in intron 4 g.36220delinsAT (rs338143418). Frequency analysis of the genotypes of these polymorphisms in the WNT7A gene showed departure from Hardy-Weinberg equilibrium for PLW at locus g.36220delinsAT and for total breeds and PLW at locus g.36251G>A. Generally, the largest litters were found in sows with AA genotypes for mutations g.6270G>A and g.36251G>A and in sows with ins/ins genotype for mutation g.3622delinsAT . However, the sows of these genotypes formed only a small percentage (from 9% to 13%) in the studied group of animals. Statistical analysis showed significant differences only for the number of piglets born and reared in parity 1 (1NBA and 1N21d) in favor of the sows with genotype AA g.6270G>A (P≤0.05) and for the number of piglets born in litter 4 (4NBA) with genotype ins/ins g.3622delinsAT (P≤0.05). The analysed mutations had no effect on the age at first farrowing and the successive farrowing intervals.

Decreased expression of WNT2 in villi of unexplained recurrent spontaneous abortion patients may cause trophoblast cell dysfunction via downregulated Wnt/β-catenin signaling pathway

WNT2 has been reported to be important for placental development, especially for the proper vascularization of the placenta. However, its precise role in first-trimester trophoblast cells is still unknown. WNT2 expression in the villous tissues of unexplained recurrent spontaneous abortion (URSA) patients was compared with that of healthy women by Western blot. The function of WNT2 in HTR-8/SVneo trophoblast cells was evaluated by altering the cellular WNT2 level through overexpression and shRNA knockdown. The molecular mechanism of the effect of WNT2 on trophoblast cells was investigated. The association of WNT2 with the Wnt/β-catenin signaling pathway was studied through Western blot and immunofluorescence. Results showed that WNT2 protein expression was significantly decreased in villi of the URSA group compared with the control group. In vitro studies showed that WNT2 could promote human trophoblast cell proliferation and migration through activating the Wnt/β-catenin signaling pathway. Moreover, upon the knockdown of WNT2, trophoblast cell proliferation and migration were significantly suppressed. In conclusion, our study indicated that WNT2 plays an important role in trophoblast function. WNT2 insufficiency might cause impaired trophoblast cell proliferation and migration via downregulation of Wnt/β-catenin signaling pathway.

Wnt/β-catenin signaling pathway in severe preeclampsia

This study aims to elucidate the mechanisms of Wnt/β-catenin signaling pathway in the development of preeclampsia (PE). The mRNA levels of Wnt1, β-catenin, c-myc and cyclinD1 were determined by real-time PCR in the placentas. Moreover, the expression levels of Wnt1, β-catenin, Dickkopf-1 (DKK1) and glycogen synthase kinase 3β (GSK-3β) proteins were detected by Western blot. Immunohistochemistry was used in placental tissue microarray to localize the expression of Wnt1, β-catenin, DKK1 proteins in the placentas of two groups. Compared with the control placentas, the mRNA levels of Wnt1, β-catenin, c-myc and cyclinD1 were decreased in the severe preeclamptic placentas. The Western blot results showed that the expression levels of Wnt1, β-catenin, and GSK-3β proteins were significantly elevated in the control group, while the expression level of DKK1 was significantly decreased. In addition, the staining intensity of Wnt1, β-catenin were weaker in the placentas of the severe PE group while the staining intensity of DKK1 was significantly stronger in the placentas of the severe PE group. Wnt/β-catenin signaling pathway may play a significant role in the pathogenesis of PE by regulating the invasion and proliferation of trophoblast.