Acquisition and Exaptation of Endogenous Retroviruses in Mammalian Placenta.

Endogenous retroviruses (ERVs) are retrovirus-like sequences that were previously integrated into the host genome. Although most ERVs are inactivated by mutations, deletions, or epigenetic regulation, some remain transcriptionally active and impact host physiology. Several ERV-encoded proteins, such as Syncytins and Suppressyn, contribute to placenta acquisition, a crucial adaptation in mammals that protects the fetus from external threats and other risks while enabling the maternal supply of oxygen, nutrients, and antibodies. In primates, Syncytin-1 and Syncytin-2 facilitate cell-cell fusion for placental formation. Suppressyn is the first ERV-derived protein that inhibits cell fusion by binding to ASCT2, the receptor for Syncytin-1. Furthermore, Syncytin-2 likely inserted into the genome of the common ancestor of Anthropoidea, whereas Syncytin-1 and Suppressyn likely inserted into the ancestor of catarrhines; however, they were inactivated in some lineages, suggesting that multiple exaptation events had occurred. This review discusses the role of ERV-encoded proteins, particularly Syncytins and Suppressyn, in placental development and function, focusing on the integration of ERVs into the host genome and their contribution to the genetic mechanisms underlying placentogenesis. This review provides valuable insights into the molecular and genetic aspects of placentation, potentially shedding light on broader evolutionary and physiological processes in mammals.

The AKT1-FOXO4 axis reciprocally regulates hemochorial placentation.

Hemochorial placentation involves the differentiation of invasive trophoblast cells, specialized cells that possess the capacity to exit the placenta and invade into the uterus where they restructure the vasculature. Invasive trophoblast cells arise from a well-defined compartment within the placenta, referred to as the junctional zone in rat and the extravillous trophoblast cell column in human. In this study, we investigated roles for AKT1, a serine/threonine kinase, in placental development using a genome-edited/loss-of-function rat model. Disruption of AKT1 resulted in placental, fetal and postnatal growth restriction. Forkhead box O4 (Foxo4), which encodes a transcription factor and known AKT substrate, was abundantly expressed in the junctional zone and in invasive trophoblast cells of the rat placentation site. Foxo4 gene disruption using genome editing resulted in placentomegaly, including an enlarged junctional zone. AKT1 and FOXO4 regulate the expression of many of the same transcripts expressed by trophoblast cells, but in opposite directions. In summary, we have identified AKT1 and FOXO4 as part of a regulatory network that reciprocally controls critical indices of hemochorial placenta development.

Epigenetic control of the imprinted growth regulator Cdkn1c in cadmium-induced placental dysfunction.

Cadmium (Cd) is a toxic metal ubiquitous in the environment. In utero, Cd is inefficiently transported to the foetus but causes foetal growth restriction (FGR), likely through impairment of the placenta where Cd accumulates. However, the underlying molecular mechanisms are poorly understood. Cd can modulate the expression of imprinted genes, defined by their transcription from one parental allele, which play critical roles in placental and foetal growth. The expression of imprinted genes is governed by DNA methylation at Imprinting Control Regions (ICRs), which are susceptible to environmental perturbation. The imprinted gene Cdkn1c/CDKN1C is a major regulator of placental development, is implicated in FGR, and shows increased expression in response to Cd exposure in mice. Here, we use a hybrid mouse model of in utero Cd exposure to determine if the increase in placental Cdkn1c expression is caused by changes to ICR DNA methylation and loss of imprinting (LOI). Consistent with prior studies, Cd causes FGR and impacts placental structure and Cdkn1c expression at late gestation. Using polymorphisms to distinguish parental alleles, we demonstrate that increased Cdkn1c expression is not driven by changes to DNA methylation or LOI. We show that Cdkn1c is expressed primarily in the placental labyrinth which is proportionally increased in size in response to Cd. We conclude that the Cd-associated increase in Cdkn1c expression can be fully explained by alterations to placental structure. These results have implications for understanding mechanisms of Cd-induced placental dysfunction and, more broadly, for the study of FGR associated with increased Cdkn1c/CDKN1C expression.

The roles of ADAMDEC1 in trophoblast differentiation during normal pregnancy and preeclampsia.

Human cytotrophoblast (CTB) differentiation into syncytiotrophoblast (STB) is essential for placental formation and function. Understanding the molecular mechanisms involved in trophoblast differentiation is necessary as it would help in the development of novel therapeutic agents to treat placentation-mediated pregnancy complications. In this study, we found a common upregulated gene, ADAM-like Decysin-1 (ADAMDEC1), from five published microarray and RNA-sequencing datasets. Interference to ADAMDEC1 impaired forskolin-induced BeWo cells differentiation, while ADAMDEC1 overexpression promoted BeWo cells and 3D JEG-3 spheroids differentiation. Interestingly, ADAMDEC1 may inhibit Thrombospondin 1 rather than E-cadherin to trigger the activation of the cAMP signal pathway during CTB differentiation into STB. More importantly, a decreasing in ADAMDEC1 might be involved in the development of preeclampsia. Therefore, ADAMDEC1 is expected to become a new target for prediction of and intervention in placenta-derived pregnancy diseases.

Placental Dysfunction in Assisted Reproductive Pregnancies: Perinatal, Neonatal and Adult Life Outcomes.

Obstetric and newborn outcomes of assisted reproductive technology (ART) pregnancies are associated with significative prevalence of maternal and neonatal adverse health conditions, such as cardiovascular and metabolic diseases. These data are interpreted as anomalies in placentation involving a dysregulation of several molecular factors and pathways. It is not clear which extent of the observed placental alterations are the result of ART and which originate from infertility itself. These two aspects probably act synergically for the final obstetric risk. Data show that mechanisms of inappropriate trophoblast invasion and consequent altered vascular remodeling sustain several clinical conditions, leading to obstetric and perinatal risks often found in ART pregnancies, such as preeclampsia, fetal growth restriction and placenta previa or accreta. The roles of factors such as VEGF, GATA3, PIGF, sFLT-1, sEndoglin, EGFL7, melatonin and of ART conditions, such as short or long embryo cultures, trophectoderm biopsy, embryo cryopreservation, and supraphysiologic endometrium preparation, are discussed. Inflammatory local conditions and epigenetic influence on embryos of ART procedures are important research topics since they may have important consequences on obstetric risk. Prevention and treatment of these conditions represent new frontiers for clinicians and biologists involved in ART, and synergic actions with researchers at molecular levels are advocated.

Transient Hyperglycemia and Hypoxia Induce Memory Effects in AngiomiR Expression Profiles of Feto-Placental Endothelial Cells.

Gestational diabetes (GDM) and preeclampsia (PE) are associated with fetal hyperglycemia, fetal hypoxia, or both. These adverse conditions may compromise fetal and placental endothelial cells. In fact, GDM and PE affect feto-placental endothelial function and also program endothelial function and cardiovascular disease risk of the offspring in the long-term. MicroRNAs are short, non-coding RNAs that regulate protein translation and fine tune biological processes. A group of microRNAs termed angiomiRs is particularly involved in the regulation of endothelial function. We hypothesized that transient hyperglycemia and hypoxia may alter angiomiR expression in feto-placental endothelial cells (fpEC). Thus, we isolated primary fpEC after normal, uncomplicated pregnancy, and induced hyperglycemia (25 mM) and hypoxia (6.5%) for 72 h, followed by reversal to normal conditions for another 72 h. Current vs. transient effects on angiomiR profiles were analyzed by RT-qPCR and subjected to miRNA pathway analyses using DIANA miRPath, MIENTURNET and miRPathDB. Both current and transient hypoxia affected angiomiR profile stronger than current and transient hyperglycemia. Both stimuli altered more angiomiRs transiently, i.e., followed by 72 h culture at control conditions. Pathway analysis revealed that hypoxia significantly altered the pathway 'Proteoglycans in cancer'. Transient hypoxia specifically affected miRNAs related to 'adherens junction'. Our data reveal that hyperglycemia and hypoxia induce memory effects on angiomiR expression in fpEC. Such memory effects may contribute to long-term adaption and maladaption to hyperglycemia and hypoxia.

Novel Technologies for Target Delivery of Therapeutics to the Placenta during Pregnancy: A Review.

Uterine spiral artery remodeling is essential for placental perfusion and fetal growth and, when impaired, results in placental ischemia and pregnancy complications, e.g., fetal growth restriction, preeclampsia, premature birth. Despite the high incidence of adverse pregnancies, current treatment options are limited. Accordingly, research has shifted to the development of gene therapy technologies that provide targeted delivery of "payloads" to the placenta while limiting maternal and fetal exposure. This review describes the current strategies, including placental targeting peptide-bound liposomes, nanoparticle or adenovirus constructs decorated with specific peptide sequences and placental gene promoters delivered via maternal IV injection, directly into the placenta or the uterine artery, as well as noninvasive site-selective targeting of regulating genes conjugated with microbubbles via contrast-enhanced ultrasound. The review also provides a perspective on the effectiveness of these technologies in various animal models and their practicability and potential use for targeted placental delivery of therapeutics and genes in adverse human pregnancies affected by placental dysfunction.

A mechanoresponsive PINCH-1-Notch2 interaction regulates smooth muscle differentiation of human placental mesenchymal stem cells.

Extracellular matrix (ECM) stiffness plays an important role in the decision making process of smooth muscle differentiation of mesenchymal stem cells (MSCs) but the underlying mechanisms are incompletely understood. Here we show that a signaling axis consisting of PINCH-1 and Notch2 is critically involved in mediating the effect of ECM stiffness on smooth muscle differentiation of MSCs. Notch2 level is markedly increased in ECM stiffness-induced smooth muscle differentiation of human placental MSCs. Knockdown of Notch2 from human placental MSCs effectively inhibits ECM stiffness-induced smooth muscle differentiation, whereas overexpression of North intracellular domain (NICD2) is sufficient to drive human placental MSC differentiation toward smooth muscle cells. At the molecular level, Notch2 directly interacts with PINCH-1. The interaction of Notch2 with PINCH-1 is significantly increased in response to ECM stiffness favoring smooth muscle differentiation. Furthermore, depletion of PINCH-1 from human placental MSCs reduces Notch2 level and consequently suppresses ECM stiffness-induced smooth muscle differentiation. Re-expression of PINCH-1, but not that of a Notch2-binding defective PINCH-1 mutant, in PINCH-1 knockdown human placental MSCs restores smooth muscle differentiation. Finally, overexpression of NICD2 is sufficient to override PINCH-1 deficiency-induced defect in smooth muscle differentiation. Our results identify an ECM stiffness-responsive PINCH-1-Notch2 interaction that is critically involved in ECM stiffness-induced smooth muscle differentiation of human placental MSCs.

The immune-modulating pregnancy-specific glycoproteins evolve rapidly and their presence correlates with hemochorial placentation in primates.

BACKGROUND: Pregnancy-specific glycoprotein (PSG) genes belong to the carcinoembryonic antigen (CEA) gene family, within the immunoglobulin gene superfamily. In humans, 10 PSG genes encode closely related secreted glycoproteins. They are exclusively expressed in fetal syncytiotrophoblast cells and represent the most abundant fetal proteins in the maternal blood. In recent years, a role in modulation of the maternal immune system possibly to avoid rejection of the semiallogeneic fetus and to facilitate access of trophoblast cells to maternal resources via the blood system has been suggested. Alternatively, they could serve as soluble pathogen decoy receptors like other members of the CEA family. Despite their clearly different domain organization, similar functional properties have also been observed for murine and bat PSG. As these species share a hemochorial type of placentation and a seemingly convergent formation of PSG genes during evolution, we hypothesized that hemochorial placentae support the evolution of PSG gene families. RESULTS: To strengthen this hypothesis, we have analyzed PSG genes in 57 primate species which exhibit hemochorial or epitheliochorial placentation. In nearly all analyzed apes some 10 PSG genes each could be retrieved from genomic databases, while 6 to 24 PSG genes were found in Old World monkey genomes. Surprisingly, only 1 to 7 PSG genes could be identified in New World monkeys. Interestingly, no PSG genes were found in more distantly related primates with epitheliochorial placentae like lemurs and lorises. The exons encoding the putative receptor-binding domains exhibit strong selection for diversification in most primate PSG as revealed by rapid loss of orthologous relationship during evolution and high ratios of nonsynonymous and synonymous mutations. CONCLUSION: The distribution of trophoblast-specific PSGs in primates and their pattern of selection supports the hypothesis that PSG are still evolving to optimize fetal-maternal or putative pathogen interactions in mammals with intimate contact of fetal cells with the immune system of the mother like in hemochorial placentation.

Haldane's rule in the placenta: Sex-biased misregulation of the Kcnq1 imprinting cluster in hybrid mice.

Hybrid phenotypes that contribute to postzygotic reproductive isolation often exhibit pronounced asymmetry, both between reciprocal crosses and between the sexes in accordance with Haldane's rule. Inviability in mammalian hybrids is associated with parent-of-origin placental growth abnormalities for which misregulation of imprinted gene (IGs) is the leading candidate mechanism. However, direct evidence for the involvement of IGs in hybrid growth dysplasia is limited. We used transcriptome and reduced representation bisulfite sequencing to conduct the first genome-scale assessment of the contribution of IGs to parent-of-origin placental growth dysplasia in the cross between the house mouse (Mus musculus domesticus) and the Algerian mouse (Mus spretus). IGs with transgressive expression and methylation were concentrated in the Kcnq1 cluster, which contains causal genes for prenatal growth abnormalities in mice and humans. Hypermethylation of the cluster's imprinting control region, and consequent misexpression of the genes Phlda2 and Ascl2, is a strong candidate mechanism for transgressive placental undergrowth. Transgressive placental and gene regulatory phenotypes, including expression and methylation in the Kcnq1 cluster, were more extreme in hybrid males. Although consistent with Haldane's rule, male-biased defects are unexpected in rodent placenta because the X-chromosome is effectively hemizygous in both sexes. In search of an explanation, we found evidence of leaky imprinted (paternal) X-chromosome inactivation in hybrid female placenta, an epigenetic disturbance that may buffer females from the effects of X-linked incompatibilities to which males are fully exposed. Sex differences in chromatin structure on the X and sex-biased maternal effects are nonmutually exclusive alternative explanations for adherence to Haldane's rule in hybrid placenta. The results of this study contribute to understanding the genetic basis of hybrid inviability in mammals, and the role of IGs in speciation.

Functional Evaluation of STOX1 (STORKHEAD-BOX PROTEIN 1) in Placentation, Preeclampsia, and Preterm Birth.

Revaluation of the association of the STOX1 (STORKHEAD_BOX1 PROTEIN 1) transcription factor mutation (Y153H, C allele) with the early utero-vascular origins of placental pathology is warranted. To investigate if placental STOX1 Y153H genotype affects utero-vascular remodeling-compromised in both preterm birth and preeclampsia-we utilized extravillous trophoblast (EVT) explant and placental decidual coculture models, transfection of STOX1 wild-type and mutant plasmids into EVT-like trophoblast cell lines, and a cohort of 75 placentas from obstetric pathologies. Primary EVT and HTR8/SVneo cells carrying STOX1 Y153H secreted lower levels of IL (interleukin) 6, and IL-8, and higher CXCL16 (chemokine [C-X-C motif] ligand 16) and TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) than wild-type EVT and Swan71 cells. Media from wild-type EVT or Swan71 cells transfected with wild-type STOX1 stimulated: endothelial chemokine expression, angiogenesis, and decidual natural killer cell and monocyte migration. In contrast, Y153H EVT conditioned medium, Swan71 transfected with the Y153H plasmid, or HTR8/SVneo media had no effect. Genotyping of placental decidual cocultures demonstrated association of the placental STOX1 CC allele with failed vascular remodeling. Decidual GG NODAL R165H increased in failed cocultures carrying the placental CC alleles of STOX1. Multivariate analysis of the placental cohort showed that the STOX1 C allele correlated with premature birth, with or without severe early-onset preeclampsia, and small for gestational age babies. In conclusion, placental STOX1 Y153H is a precipitating factor in preterm birth and placental preeclampsia due to defects in early utero-placental development.

Transcription Factor PLAGL1 Is Associated with Angiogenic Gene Expression in the Placenta.

During pregnancy, the placenta is important for transporting nutrients and waste between the maternal and fetal blood supply, secreting hormones, and serving as a protective barrier. To better understand placental development, we must understand how placental gene expression is regulated. We used RNA-seq data and ChIP-seq data for the enhancer associated mark, H3k27ac, to study gene regulation in the mouse placenta at embryonic day (e) 9.5, when the placenta is developing a complex network of blood vessels. We identified several upregulated transcription factors with enriched binding sites in e9.5-specific enhancers. The most enriched transcription factor, PLAGL1 had a predicted motif in 233 regions that were significantly associated with vasculature development and response to insulin stimulus genes. We then performed several experiments using mouse placenta and a human trophoblast cell line to understand the role of PLAGL1 in placental development. In the mouse placenta, Plagl1 is expressed in endothelial cells of the labyrinth layer and is differentially expressed in placentas from mice with gestational diabetes compared to placentas from control mice in a sex-specific manner. In human trophoblast cells, siRNA knockdown significantly decreased expression of genes associated with placental vasculature development terms. In a tube assay, decreased PLAGL1 expression led to reduced cord formation. These results suggest that Plagl1 regulates overlapping gene networks in placental trophoblast and endothelial cells, and may play a critical role in placental development in normal and complicated pregnancies.

Integrated microarray analysis of key genes and a miRNA­mRNA regulatory network of early­onset preeclampsia.

Early­onset preeclampsia (EOPE) is a serious threat to maternal and foetal health. The present study aimed to identify potential biomarkers and targets for the treatment of EOPE. Expression profiles of placenta from patients with EOPE and healthy controls (GSE103542, GSE74341 and GSE44711) were downloaded from the Gene Expression Omnibus database. Integrated analysis revealed 246 genes and 28 microRNAs (miRNAs) that were differentially expressed between patients with EOPE and healthy controls. Differentially expressed genes (DEGs) were primarily enriched in 'biological processes', such as 'cell adhesion', 'female pregnancy', 'extracellular matrix organization' and 'response to hypoxia'. Significant pathways associated with DEGs primarily included 'focal adhesion', 'ECM­receptor interaction', 'PI3K­Akt signaling' and 'ovarian steroidogenesis'. A Protein­Protein Interaction network of DEGs was constructed using the Search Tool for the Retrieval of Interacting Genes/Proteins online database, and epidermal growth factor receptor, collagen α­1(I) chain, secreted phosphoprotein 1, leptin (LEP), collagen α­2(I) chain (COL1A2), plasminogen activator inhibitor 1 (SERPINE1), Thy­1 membrane glycoprotein, bone morphogenetic protein 4, vascular cell adhesion protein 1 and matrix metallopeptidase 1 were identified as hub genes. The alterations of hsa­miR­937, hsa­miR­148b*, hsa­miR­3907, hsa­miR­367*, COL1A2, LEP and SERPINE1 in placenta were validated using our local samples. Our research showed that the expression of hsa­miR­937, hsa­miR­1486*, hsa­miR­3907, hsa­miR­367* and hub genes in the placenta were closely associated with the pathophysiology of EOPE. hsa­miR­937, hsa­miR­1486*, hsa­miR­3907, hsa­miR­367* and hub genes could serve as biomarkers for diagnosis and as potential targets for the treatment of EOPE.

MicroRNA­491­5p inhibits trophoblast cell migration and invasion through targeting matrix metalloproteinase­9 in preeclampsia.

Insufficient invasion of trophoblasts is correlated with the development of preeclampsia (PE). MicroRNA (miR)­491­5p has been reported to be implicated in human cancer cell invasion; however, whether miR­491­5p is involved in the development of PE remains largely unclear. The aim of the present study was to investigate the role of miR­491­5p in trophoblastic invasion in vitro and to determine its underlying mechanism of action. The expression levels of miR­491­5p were validated using reverse transcription­quantitative PCR. The effects of miR­491­5p on trophoblast cell invasion were evaluated in vitro. Then, the association between miR­491­5p and its downstream target was investigated in both cell lines and clinical specimens. miR­491­5p expression levels were observed to be significantly increased in the placental tissues from patients with PE. The invasive capacity of HTR­8/SVneo trophoblast cells was suppressed following the upregulation of miR­491­5p and increased following the inhibition of miR­491­5p. Matrix metalloproteinase­9 (MMP­9), a well­known regulator of trophoblast cell invasion, was discovered to be a direct target of miR­491­5p in HTR­8/SVneo trophoblast cells. Moreover, miR­491­5p expression levels were found to be inversely correlated with MMP­9 expression levels in placental tissues from patients with PE. The overexpression of MMP­9 partly attenuated the inhibitory effects of miR­491­5p on HTR­8/SVneo trophoblast cells invasion. Collectively, these findings suggested that the aberrant expression of miR­491­5p may contribute to PE through suppressing trophoblast invasion, thus highlighting the novel roles of miR­491­5p in the molecular pathogenesis of PE. The present study also showed that the miR­491­5p/MMP­9 axis may be an effective biomarker or a viable drug target for therapeutic intervention in PE.

Persistent Human KIT Receptor Signaling Disposes Murine Placenta to Premature Differentiation Resulting in Severely Disrupted Placental Structure and Functionality.

Activating mutations in the human KIT receptor is known to drive severe hematopoietic disorders and tumor formation spanning various entities. The most common mutation is the substitution of aspartic acid at position 816 to valine (D816V), rendering the receptor constitutively active independent of ligand binding. As the role of the KIT receptor in placental signaling cascades is poorly understood, we analyzed the impact of KITD816V expression on placental development using a humanized mouse model. Placentas from KITD816V animals present with a grossly changed morphology, displaying a reduction in labyrinth and spongiotrophoblast layer and an increase in the Parietal Trophoblast Giant Cell (P-TGC) layer. Elevated differentiation to P-TGCs was accompanied with reduced differentiation to other Trophoblast Giant Cell (TGC) subtypes and by severe decrease in proliferation. The embryos display growth retardation and die in utero. KITD816V-trophoblast stem cells (TSC) differentiate much faster compared to wild type (WT) controls. In undifferentiated KITD816V-TSCs, levels of Phosphorylated Extracellular-signal Regulated Kinase (P-ERK) and Phosphorylated Protein Kinase B (P-AKT) are comparable to wildtype cultures differentiating for 3-6 days. Accordingly, P-TGC markers Placental Lactogen 1 (PL1) and Proliferin (PLF) are upregulated as well. The results reveal that KIT signaling orchestrates the fine-tuned differentiation of the placenta, with special emphasis on P-TGC differentiation. Appropriate control of KIT receptor action is therefore essential for placental development and nourishment of the embryo.

MiR-519d-3p in Trophoblastic Cells: Effects, Targets and Transfer to Allogeneic Immune Cells via Extracellular Vesicles.

Members of the placenta-specific miRNA cluster C19MC, including miR-519d, are secreted by fetal trophoblast cells within extracellular vesicles (EVs). Trophoblast-derived EVs can be internalized by the autologous trophoblast and surrounding maternal immune cells, resulting in coordination of cellular responses. The study of functions and targets of placental miRNAs in the donor and recipient cells may contribute to the understanding of the immune tolerance essential in pregnancy. Here, we report that miR-519d-3p levels correlate positively with cell proliferation and negatively with migration in trophoblastic cell lines. Inhibition of miR-519d-3p in JEG-3 cells increases caspase-3 activation and apoptosis. PDCD4 and PTEN are targeted by miR-519d-3p in a cell type-specific manner. Transfection of trophoblastic cell lines with miR-519d mimic results in secretion of EVs containing elevated levels of this miRNA (EVmiR-519d). Autologous cells enhance their proliferation and decrease their migration ability when treated with EVmiR-519d. NK92 cells incorporate EV-delivered miR-519d-3p at higher levels than Jurkat T cells. EVmiR-519d increases the proliferation of Jurkat T cells but decreases that of NK92 cells. Altogether, miR-519d-3p regulates pivotal trophoblast cell functions, can be transferred horizontally via EVs to maternal immune cells and exerts functions therein. Vesicular miRNA transfer from fetal trophoblasts to maternal immune cells may contribute to the immune tolerance in pregnancy.

Baby Genomics: Tracing the Evolutionary Changes That Gave Rise to Placentation.

It has long been challenging to uncover the molecular mechanisms behind striking morphological innovations such as mammalian pregnancy. We studied the power of a robust comparative orthology pipeline based on gene synteny to address such problems. We inferred orthology relations between human genes and genes from each of 43 other vertebrate genomes, resulting in ∼18,000 orthologous pairs for each genome comparison. By identifying genes that first appear coincident with origin of the placental mammals, we hypothesized that we would define a subset of the genome enriched for genes that played a role in placental evolution. We thus pinpointed orthologs that appeared before and after the divergence of eutherian mammals from marsupials. Reinforcing previous work, we found instead that much of the genetic toolkit of mammalian pregnancy evolved through the repurposing of preexisting genes to new roles. These genes acquired regulatory controls for their novel roles from a group of regulatory genes, many of which did in fact originate at the appearance of the eutherians. Thus, orthologs appearing at the origin of the eutherians are enriched in functions such as transcriptional regulation by Krüppel-associated box-zinc-finger proteins, innate immune responses, keratinization, and the melanoma-associated antigen protein class. Because the cellular mechanisms of invasive placentae are similar to those of metastatic cancers, we then used our orthology inferences to explore the association between placenta invasion and cancer metastasis. Again echoing previous work, we find that genes that are phylogenetically older are more likely to be implicated in cancer development.

Dihydrotestosterone potentiates insulin to up-regulate prokineticin-1 in decidualizing human endometrial stromal cells.

Prokineticin 1 (PROK1) is a key regulator of embryo implantation and placentation, and its dysregulation is associated with pregnancy complications, such as pre-eclampsia and foetal growth restriction. We have previously shown that insulin strongly enhances the expression of PROK1 in human decidualizing stromal cells. Here, we demonstrate that dihydrotestosterone (DHT), but not testosterone, potentiates insulin to up-regulate PROK1 in these cells. However, the androgens alone do not influence the expression of PROK1. Our findings suggest that insulin and androgens both are involved in the regulation of PROK1 that could have implications for normal and pathological pregnancies.

Interplay between neutrophils and trophoblast cells conditions trophoblast function and triggers vascular transformation signals.

Normal placentation entails highly regulated interactions of maternal leukocytes with vascular and trophoblast cells to favor vascular transformation. Neutrophil activation and neutrophil extracellular trap (NET) formation associate with poor placentation and severe pregnancy complications. To deepen into the mechanisms of trophoblast-neutrophil interaction, we explored the effects of NETs on trophoblast cell function and, conversely, whether trophoblast cell-derived factors condition neutrophils to favor angiogenesis and anti-inflammatory signals required for fetal growth. NETs isolated from activated neutrophils hindered trophoblast cell migration. Trophoblast conditioned media prevented the effect as well as the vasoactive intestinal peptide (VIP) known to regulate trophoblast and neutrophil function. On the other hand, factors released by trophoblast cells and VIP shaped neutrophils to a proangiogenic profile with increased vascular endothelial growth factor synthesis and increased capacity to promote vascular transformation. Results presented here provide novel clues to reconstruct the interaction of trophoblast cells and neutrophils in vivo during placentation in humans.

Preeclampsia: a defect in decidualization is associated with deficiency of Annexin A2.

BACKGROUND: Decidualization defects in the endometrium have been demonstrated at the time of delivery in women with severe preeclampsia and to linger for years, which suggests a maternal contribution to the pathogenesis of this condition. Global transcriptional profiling reveals alterations in gene expression, which includes down-regulation of Annexin A2 in severe preeclampsia patients with decidualization resistance. OBJECTIVE: We investigated the functional role of Annexin A2 deficiency during endometrial decidualization and its potential contribution to shallow trophoblast invasion during implantation and subsequent placentation using in vitro and in vivo modeling. STUDY DESIGN: Annexin A2 gene and protein levels were assessed during in vitro decidualization of human endometrial stromal cells isolated from biopsy specimens that were collected from women with previous severe preeclampsia (n=5) or normal obstetric outcomes (n=5). Next, Annexin A2 was inhibited with small interference RNA in control human endometrial stromal cells that were isolated from endometrial biopsy specimens (n=15) as an in vitro model to analyze decidualization defects at the morphologic level and the secretion of prolactin and insulin-like growth binding protein-1. Annexin A2-inhibited cells were used to evaluate motility and promotion of embryo invasion. Decidualization and placentation defects of Annexin A2 deficiency were confirmed with the use of an Annexin A2-null mouse model. RESULTS: Annexin A2 gene and protein levels were down-regulated during in vitro decidualization of human endometrial stromal cells from women with previous severe preeclampsia compared with control individuals. To assess its role in the endometrial stroma, we inhibited Annexin A2 expression and detected decidualization failure as evidenced by impaired morphologic transformation, which was associated with altered actin polymerization and low prolactin and insulin-like growth binding protein-1 secretions. Functionally, in vitro models demonstrated that Annexin A2 inhibition failed to support embryo invasion. This finding was corroborated by reduced trophoblast spreading through human endometrial stromal cells, lack of motility of these cells, and reduced trophoblast invasion in the presence of conditioned media from Annexin A2-inhibited cells. Extending our discovery to an animal model, we detected that Annexin A2-null mice have a functional deficiency in decidualization and placentation that impairs fetal growth as a feature that is associated with severe preeclampsia. CONCLUSION: Together, in vitro and in vivo results suggest that endometrial defects in Annexin A2 expression impair decidualization of endometrial stromal cells as well as the uterine microenvironment that promotes embryo implantation and placentation. Our findings highlight the maternal contribution to the pathogenesis of severe preeclampsia and suggest that evaluation of Annexin A2 may provide a novel strategy to assess a woman's risk of experiencing this disease and perhaps discover therapeutic interventions to improve decidualization.