Decidual-secreted factors alter invasive trophoblast membrane and secreted proteins implying a role for decidual cell regulation of placentation

Decidualized Endometrial Stromal Cells Promote Mitochondrial Beta-Oxidation to Produce the Octanoic Acid Required for Implantation

Decidualization denotes the morphological and biological differentiating process of human endometrial stromal cells (HESCs). Fatty acid pathways are critical for endometrial decidualization. However, the participation of fatty acids as an energy source and their role in endometrial decidualization have received little attention. To identify fatty acids and clarify their role in decidualization, we comprehensively evaluated free fatty acid profiles using liquid chromatography/Fourier transform mass spectrometry (LC/FT-MS). LC/FT-MS analysis detected 26 kinds of fatty acids in the culture medium of decidualized or un-decidualized HESCs. Only the production of octanoic acid, which is an essential energy source for embryonic development, was increased upon decidualization. The expressions of genes related to octanoic acid metabolism including ACADL, ACADM, and ACADS; genes encoding proteins catalyzing the first step of mitochondrial fatty acid beta-oxidation; and ACSL5 and ACSM5; genes encoding fatty acid synthesis proteins were significantly altered upon decidualization. These results suggest that decidualization promotes lipid metabolism, implying that decidualized HESCs require energy metabolism of the mitochondria in embryo implantation.

HB-EGF-loaded nanovesicles enhance trophectodermal spheroid attachment and invasion

The ability of trophectodermal cells (outer layer of the embryo) to attach to the endometrial cells and subsequently invade the underlying matrix are critical stages of embryo implantation during successful pregnancy establishment. Extracellular vesicles (EVs) have been implicated in embryo-maternal crosstalk, capable of reprogramming endometrial cells towards a pro-implantation signature and phenotype. However, challenges associated with EV yield and direct loading of biomolecules limit their therapeutic potential. We have previously established generation of cell-derived nanovesicles (NVs) from human trophectodermal cells (hTSCs) and their capacity to reprogram endometrial cells to enhance adhesion and blastocyst outgrowth. Here, we employed a rapid NV loading strategy to encapsulate potent implantation molecules such as HB-EGF (NVHBEGF). We show these loaded NVs elicit EGFR-mediated effects in recipient endometrial cells, activating kinase phosphorylation sites that modulate their activity (AKT S124/129, MAPK1 T185/Y187), and downstream signalling pathways and processes (AKT signal transduction, GTPase activity). Importantly, they enhanced target cell attachment and invasion. The phosphoproteomics and proteomics approach highlight NVHBEGF-mediated short-term signalling patterns and long-term reprogramming capabilities on endometrial cells which functionally enhance trophectodermal-endometrial interactions. This proof-of-concept study demonstrates feasibility in enhancing the functional potency of NVs in the context of embryo implantation.

Expression and significance of cathepsin C and cathepsin D during pregnancy and Preeclampsia

BACKGROUND

Cathepsin C (Cat C) is involved in the inflammatory-immune system and can be degraded by cathepsin D (Cat D). Preeclampsia (PE) and the inflammation-immunity relationship is currently a hot research topic, but there are still few studies. The aim was to investigate the expression and significance of Cat C and D in the serum of nonpregnant women, patients in various stages of pregnancy and patients with PE, and in the placenta of patients with normal pregnancy and PE.

METHODS

Sixty young healthy nonpregnant women were selected: 180 normal pregnant women, including 60 each in the first, second, and third trimesters, and 100 women with PE, including 39 women with severe preeclampsia. The levels of Cat C and D in serum were detected by enzyme-linked immunosorbent assay (ELISA), and the expression levels of Cat C and D in placentas were detected by immunohistochemistry (IHC).

RESULTS

The serum of Cat C in the first trimester was significantly lower than that in the nonpregnant group (P < 0.001), whereas Cat D was significantly higher than that in the nonpregnant group (P < 0.01). The levels of Cat C and D in the second trimester and third trimester were significantly higher than those in the first trimester (P < 0.05), but there was no significant difference in Cat C and D between the second trimester and third trimester. The levels of Cat C in the serum and placentas of patients with PE were significantly higher than those in the third trimester (P < 0.001) and positively correlated with the severity of PE (P < 0.001), whereas the levels of Cat D in the serum and placentas of patients with PE were significantly lower than those in the third trimester (P < 0.001) and negatively correlated with the severity of PE (P < 0.001). Age, primigravida proportion, and body mass index were significantly higher in the PE group than in the control group (P < 0.05), which were high-risk factors for PE.

CONCLUSIONS

Cat C and D are associated with the maintenance of normal pregnancy. In patients with preeclampsia, a significant increase in Cat C and a significant decrease in Cat D levels may lead to the occurrence and development of preeclampsia.

Endometrial stromal cell miR-19b-3p release is reduced during decidualization implying a role in decidual-trophoblast cross-talk

INTRODUCTION

A healthy pregnancy requires successful blastocyst implantation into an adequately prepared or 'receptive' endometrium. Decidualization of uterine endometrial stromal fibroblast cells (hESF) is critical for the establishment of a healthy pregnancy. microRNAs (miRs) are critical regulators of cellular function that can be released by a donor cell to influence the physiological state of recipient cells. We aimed to determine how decidualization affects hESF miR release and investigated the function of one decidualization regulated miR, miR-19b-3p, previously shown to be associated with recurrent pregnancy loss.

METHOD

miR release by hESF was determined by miR microarray on culture media from hESF decidualized in vitro for 3 and 14 days by treatment with oestradiol and medroxyprogesterone acetate. Cellular and whole endometrial/decidual tissue miR expression was quantified by qPCR and localized by in situ hybridization. The function of miR-19b-3p in HTR8/Svneo trophoblast cells was investigated using real time cell analysis (xCELLigence) and gene expression qPCR.

RESULTS

From our miR screen we found that essentially all hESF miR release was reduced following in vitro decidualization, significantly so for miR-17-5p, miR-21-3p, miR-34c-3p, miR-106b-5p, miR-138-5p, miR-296-5p, miR-323a-3p, miR-342-3p, miR-491-5p, miR-503-5p and miR-542-5p. qPCR demonstrated that miR-19b-3p, 181a-2-3p and miR-409-5p likewise showed a significant reduction in culture media following decidualization but no change was found in cellular miR expression following decidualization. In situ hybridization localized miR-19b-3p to epithelial and stromal cells in the endometrium and qPCR identified that miR-19b-3p was significantly elevated in the cycling endometrium of patients with a history of early pregnancy loss compared to normally fertile controls. Functionally, overexpression of miR-19b-3p significantly reduced HTR8/Svneo trophoblast proliferation and increased HOXA9 expression.

DISCUSSION

Our data demonstrates that decidualization represses miR release by hESFs and overexpression of miR-19b-3p was found in endometrial tissue from patients with a history of early pregnancy loss. miR-19b-3p impaired HTR8/Svneo proliferation implying a role in trophoblast function. Overall we speculate that miR release by hESF may regulate other cell types within the decidua and that appropriate release of miRs by decidualized hESF is essential for healthy implantation and placentation.

Paracrine HB-EGF signaling reduce enhanced contractile and energetic state of activated decidual fibroblasts by rebalancing SRF-MRTF-TCF transcriptional axis

Multiple parallels exist between placentation and cancer dissemination at molecular, cellular, and anatomical levels, presenting placentation as a unique model to mechanistically understand the onset of cancer metastasis. In humans, interaction of placenta and the endometrium results eventually in deep invasion of placental extravillous trophoblasts (EVTs) into the maternal stroma, a process similar to stromal trespass by disseminating carcinoma cells. In anticipation of implantation, endometrial fibroblasts (ESFs) undergo a process called decidualization during the secretory phase of the menstrual cycle. Decidualization, among other substantial changes associated with ESF differentiation, also involves a component of fibroblast activation, and myofibroblast transformation. Here, using traction force microscopy, we show that increased cellular contractility in decidualized ESFs is reversed after interaction with EVTs. We also report here the large changes in energetic state of ESFs upon decidualization, showing increased oxidative phosphorylation, mitochondrial competency and ATP generation, as well as enhanced aerobic glycolysis, presenting mechanical contractility and energetic state as new functional hallmarks for decidualization. These energetic changes accompanying the marked increase in contractile force generation in decidualization were reduced in the presence of EVTs. We also show that increase in decidual contractility and mechanical resistance to invasion is achieved by SRF-MRTF transcriptional activation, achieved via increased phosphorylation of fibroblast-specific myosin light chain 9 (MYL9). EVT induced paracrine secretion of Heparin Binding Epidermal Growth Factor (HBEGF), a potent MAPK activator, which shifts the balance of SRF association away from MRTF based transcription, reducing decidual ESF contractility and mechanical resistance to placental invasion. Our results identify a new axis of intercellular communication in the placental bed modulating stromal force generation and resistance to invasion with concurrent downregulation of cellular energetics. These findings have important implications for implantation related disorders, as well as stromal control of cancer dissemination.

Impact of bisphenol A (BPA) on cells and tissues at the human materno-fetal interface

Bisphenol A (BPA) is an endocrine disruptor extensively used in the production of polycarbonate plastics and epoxy resins and a component of liquid and food containers. It is a hazard in the prenatal period because of its presence in the placenta, fetal membranes, amniotic fluid, maternal and fetal blood and its ability to cross the placenta and reach the fetus. Estimation of the risk of BPA exposure during in utero life is extremely important in order to prevent complications of pregnancy and fetal growth. This review describes in vitro models of the human materno-fetal interface. It also outlines the effects of BPA at doses indicated as "physiological", namely at the concentrations found in the general population, and at "supraphysiological" and "subphysiological" doses, i.e. above and below the physiological range. This work will help clarify the discrepancies observed in studies on the effects of BPA on human reproduction and pregnancy, and it will be useful for the choice of appropriate in vitro models for future studies aimed at identifying the potential impact of BPA on specific functional processes.

The proteomes of endometrial stromal cell-derived extracellular vesicles following a decidualizing stimulus define the cells' potential for decidualization success

Adequate endometrial stromal cell (ESC) decidualization is vital for endometrial health. Given the importance of extracellular vesicles (EVs) in intercellular communication, we investigated how their protein landscape is reprogrammed and dysregulated during decidual response. Small EVs (sEVs) from human ESC-conditioned media at Day-2 and -14 following decidual stimuli were grouped as well- (WD) or poorly decidualized (PD) based on their prolactin secretion and subjected to mass spectrometry-based quantitative proteomics. On Day 2, in PD- versus WD-ESC-sEVs, 17 sEV- proteins were down-regulated (C5, C6; complement/coagulation cascades, and SERPING1, HRG; platelet degranulation and fibrinolysis) and 39 up-regulated (FLNA, COL1A1; focal adhesion, ENO1, PKM; glycolysis/gluconeogenesis, and RAP1B, MSN; leukocyte transendothelial migration). On Day 14, in PD- versus WD-ESC-sEVs, FLNA was down-regulated while 21 proteins were up-regulated involved in complement/coagulation cascades (C3, C6), platelet degranulation (SERPINA4, ITIH4), B-cell receptor signalling and innate immune response (immunoglobulins). Changes from Days 2 to 14 suggested a subsequent response in PD-ESC-sEVs with 89 differentially expressed proteins mostly involved in complement and coagulation cascades (C3, C6, C5), but no change in WD-ESC-sEVs ESC. Poor decidualization was also associated with loss of crucial sEV-proteins for cell adhesion and invasion (ITGA5, PFN1), glycolysis (ALDOA, PGK1) and cytoskeletal reorganization (VCL, RAC1). Overall, this study indicates varied ESC response even prior to decidualization and provides insight into sEVs-proteomes as a benchmark of well-decidualized ESC. It shows distinct variation in sEV-protein composition depending on the ESC decidual response that is critical for embryo implantation, enabling and limiting trophoblast invasion during placentation and sensing a healthy embryo.

Decorin expression in tubal ectopic and intrauterine pregnancies

OBJECTIVE

Decorin is a leucine-rich proteoglycan, affects the proliferation, migration, and invasion of extravillous trophoblasts (EVTs). In this study, we aimed to determine the localization of decorin in the implantation site in human tubal ectopic pregnancy, to compare decorin expression levels in ectopic and intrauterine pregnancy, and to investigate the relationship between implantation depth of the tubal wall and expression levels of decorin.

METHODS

15 patients underwent salpingectomy for tubal ectopic pregnancy and 15 underwent curettage for voluntary interruption of pregnancy were included. All blocks were stained with decorin immunohistochemical staining. Trophoblastic cells of tubal Stage I-III and tubal epithelial and stromal cells were analyzed in terms of presence and intensity of decorin staining.

RESULTS

Decorin was expressed in both tubal and intrauterine trophoblasts, stroma, and surface epithelium during the first trimester of pregnancy. Decorin staining intensity was significantly lower in the villous cytotrophoblasts and syncytiotrophoblasts in tubal ectopic pregnancies, compared to intrauterine pregnancies (p = 0.001 for both). Decorin staining intensity also significantly lower in the extravillous cytotrophoblasts and syncytiotrophoblasts in the tubal ectopic pregnancies (p = 0.002 and p = 0.001, respectively). There was no significant difference in the staining intensity of the trophoblasts and surface epithelial between Stage II and Stage III tubal invasion; however, the decorin expression was lower in the stroma in Stage III (p = 0.094).

CONCLUSION

Decorin expression is significantly lower in trophoblastic cells of tubal ectopic pregnancies than the intrauterine pregnancies. Although it remains limited to explain the underlying cellular mechanisms, decorin seems to play a role in the development of tubal pregnancy.

The Primacy of Maternal Innovations to the Evolution of Embryo Implantation

Embryo implantation is a hallmark of the female reproductive biology of eutherian (placental) mammals and does not exist in a sustainable form in any other vertebrate group. Implantation is the initial process that leads to a sustained fetal-maternal unit engendering a complex functional relationship between the mother and the embryo/fetus. The nature of this relationship is often portrayed as one of conflict between an aggressive embryo and a passive or defensive maternal organism. Recent progress in elucidating the evolutionary origin of eutherian pregnancy leads to a different picture. The emerging scenario suggests that the very initial stages in the evolution of embryo implantation required evolutionary changes to the maternal physiology which modified an ancestral generic mucosal inflammation in response to the presence of the embryo into an active embedding process. This "female-first" evolutionary scenario also explains the role of endometrial receptivity in human pregnancy. On the marsupial side, where in most animals the fetal-maternal interaction is short and does not lead to a long term sustainable placentation, the relationship is mutual. In these mammals, uterine inflammation is followed by parturition in short order. The inflammatory signaling pathways, however, are cooperative, i.e., they are performed by both the fetus and the mother and therefore we call this relationship "cooperative inflammation." Based on these discoveries we reconceive the narrative of the maternal-fetal relationship.

Prednisolone Alters Endometrial Decidual Cells and Affects Decidual-Trophoblast Interactions

Poor pregnancy outcomes such as recurrent pregnancy loss (RPL) and preeclampsia are associated with impaired decidualization and abnormal trophoblast invasion. Emerging evidence suggests that use of corticosteroids, including prednisolone affects fertility by altering uterine function and may be associated with preeclampsia incidence. In this study, using primary and gestational-age appropriate tissue, we aimed to define the effect of prednisolone on human endometrial stromal fibroblast (hESF) decidualization and determine whether hESF decidualization in the presence of prednisolone would alter hESF regulation of trophoblast function. We found that prednisolone treatment reduced hESF cytokine expression (IL6, IL11, IL18, LIF, and LIFR) but had no effect on hESF expression or secretion of the classic markers of decidualization [prolactin (PRL) and IGFBP1]. Using proteomics we determined that prednisolone altered decidualized hESF protein production, enriching hESF proteins associated with acetylation and mitrochondria. Conditioned media from hESF decidualized in the presence of prednisolone significantly enhanced trophoblast outgrowth and trophoblast mRNA expression of cell motility gene PLCG1 and reduced trophoblast production of PGF. Prednisolone treatment during the menstrual cycle and 1st trimester of pregnancy might alter decidual interactions with other cells, including invasive trophoblast.

Galectin-7 Impairs Placentation and Causes Preeclampsia Features in Mice

Preeclampsia is a serious pregnancy-induced disorder unique to humans. The etiology of preeclampsia is poorly understood; however, poor placental formation is thought causal. Galectin-7 is produced by trophoblast and is elevated in first-trimester serum of women who subsequently develop preeclampsia. We hypothesized that elevated placental galectin-7 may be causative of preeclampsia. Here, we demonstrated increased galectin-7 production in chorionic villous samples from women who subsequently develop preterm preeclampsia compared with uncomplicated pregnancies. In vitro, galectin-7 impaired human first-trimester trophoblast outgrowth, increased placental production of the antiangiogenic sFlt-1 splice variant, sFlt-1-e15a, and reduced placental production and secretion of ADAM12 (a disintegrin and metalloproteinase12) and angiotensinogen. In vivo, galectin-7 administration (E8-E12) to pregnant mice caused elevated systolic blood pressure, albuminuria, impaired placentation (reduced labyrinth vascular branching, impaired decidual spiral artery remodeling, and a proinflammatory placental state demonstrated by elevated IL1β, IL6 and reduced IL10), and dysregulated expression of renin-angiotensin system components in the placenta, decidua, and kidney, including angiotensinogen, prorenin, and the angiotensin II type 1 receptor. Collectively, this study demonstrates that elevated galectin-7 during placental formation contributes to abnormal placentation and suggests that it leads to the development of preeclampsia via altering placental production of sFlt-1 and renin-angiotensin system components. Targeting galectin-7 may be a new treatment option for preeclampsia.

Profilin-1 is dysregulated in endometroid (type I) endometrial cancer promoting cell proliferation and inhibiting pro-inflammatory cytokine production

Endometrial cancer (EC) is the most common gynaecological malignancy. Alarmingly its incidence and mortality rate is increasing particularly in younger women of reproductive age. Despite this, there are limited treatment options for EC. Profilin-1 (PFN1) regulates tumorigenesis in numerous cancers, but the role of PFN1 in EC has not been investigated. We hypothesized that PFN1 would have altered expression in EC and contribute to the development of EC. We quantified PFN1 in type 1 EC and benign/normal endometrium by RT-qPCR and IHC. The effect of silencing PFN1 on cell adhesion and proliferation was investigated using 2 EC cell lines (HEC1A and AN3CA). The effect of recombinant PFN1 (100 μM) on pro-inflammatory cytokine gene expression was investigated using THP1 monocyte cell line. PFN1 immunolocalized to glandular epithelial cells, vascular endothelial cells and leukocytes in the stromal compartment of normal endometrium and EC. PFN1 immunostaining intensity was significantly elevated in grade (G)I EC compared to normal endometrium, GI-II and GIII EC. In endometrial epithelial cancer cells alone, PFN1 immunostaining intensity was significantly reduced in GII and III EC compared to normal endometrium and GI EC. The stromal compartment of EC had strong PFN1 expression compared to benign and normal endometrium. Silencing PFN1 in the AN3CA endometrial epithelial cancer cell line significantly enhanced cell adhesion and proliferation. PFN1 treatment significantly down-regulated TNFα and IL1β mRNA expression by THP1 cells. This study demonstrated that whilst PFN1 production is retained in the stromal compartment of EC, PFN1 production is lost in endometrial epithelial cancer cells with increasing cancer grade. PFN1 may play a role in the tumorigenesis of EC. Loss of PFN1 in GII and GIII endometrial epithelial cancer cells associated with sustained PFN1 by infiltrating immune cells may promote EC tumorigenesis due to increased endometrial epithelial cancer cell proliferation coupled with a pro-tolerance tumor microenvironment.

Profilin: many facets of a small protein

Profilin is a ubiquitously expressed protein well known as a key regulator of actin polymerisation. The actin cytoskeleton is involved in almost all cellular processes including motility, endocytosis, metabolism, signal transduction and gene transcription. Hence, profilin's role in the cell goes beyond its direct and essential function in regulating actin dynamics. This review will focus on the interactions of Profilin 1 and its ligands at the plasma membrane, in the cytoplasm and the nucleus of the cells and the regulation of profilin activity within those cell compartments. We will discuss the interactions of profilin in cell signalling pathways and highlight the importance of the cell context in the multiple functions that this small essential protein has in conjunction with its role in cytoskeletal organisation and dynamics. We will review some of the mechanisms that control profilin expression and the implications of changed expression of profilin in the light of cancer biology and other pathologies.

Bisphenol compounds regulate decidualized stromal cells in modulating trophoblastic spheroid outgrowth and invasion in vitro†

Bisphenol A (BPA) is commonly found in epoxy resins used in the manufacture of plastic coatings in food packaging and beverage cans. There is a growing concern about BPA as a weak estrogenic compound that can affect human endocrine function. Chemicals structurally similar to BPA, such as bisphenol F (BPF) and bisphenol S (BPS), have been developed as substitutes in the manufacturing industry. Whether these bisphenol substitutes have adverse effects on human endocrine and reproductive systems remains largely unknown. This study investigated the effects of BPA, BPF, and BPS on regulating the function of decidualized human primary endometrial stromal cells on trophoblast outgrowth and invasion by indirect and direct co-culture models. All three bisphenols did not affect the stromal cell decidualization process. However, BPA- and BPF-treated decidualized stromal cells stimulated trophoblastic spheroid invasion in the indirect coculture model. The BPA-treated decidualized stromal cells had upregulated expressions of several invasion-related molecules including leukemia inhibitory factor (LIF), whereas both BPA- and BPF-treated decidualized stromal cells had downregulated expressions of anti-invasion molecules including plasminogen activator inhibitor type 1 (PAI-1) and tumor necrosis factor (TNFα) . Taken together, BPA and BPF altered the expression of invasive and anti-invasive molecules in decidualized stromal cells modulating its function on trophoblast outgrowth and invasion, which could affect the implantation process and subsequent pregnancy outcome.

Trophoblast invasion: Lessons from abnormally invasive placenta (placenta accreta)

The invasion of the uterine wall by extravillous trophoblast is acknowledged as a crucial component of the establishment of pregnancy however, the only part of this process that has been clearly identified is the differentiation of cytotrophoblast (CTB) into the invasive extravillous trophoblast (EVT). The control of invasion, both initiation and termination, have yet to be elucidated and even the mechanism of differentiation is unclear. This review describes our studies which are designed to characterize the intracellular mechanisms that drive differentiation. We have used the over-invasion observed in abnormally invasive placenta (AIP; placenta accreta) to further interrogate this mechanism. Our results show that first trimester CTB to EVT differentiation is accomplished via an epithelial-mesenchymal transition (EMT), with EVT displaying a metastable, mesenchymal phenotype. In the third trimester, while the invasiveness of the EVT is lost, these cells still demonstrate signs of the EMT, albeit diminished. EVT isolated from AIP pregnancies do not however, show the same degree of reduction in EMT shown by normal third trimester cells. They exhibit a more mesenchymal phenotype, consistent with a legacy of greater invasiveness. The master regulatory transcription factor controlling the EMT appears, from the observational data, to be ZEB2 (zinc finger E-box binding protein 2). We verified this by overexpressing ZEB2 in the BeWo and JEG3 trophoblast cell lines and showing that they became more stellate in shape, up-regulated the expression of EMT-associated genes and demonstrated a substantially increased degree of invasiveness. The identification of the differentiation mechanism will enable us to identify the factors controlling invasion and those aberrant processes which generate the abnormal invasion seen in pathologies such as AIP and preeclampsia.

Experimental models of maternal-fetal interface and their potential use for nanotechnology applications

During pregnancy, the placenta regulates the transfer of oxygen, nutrients, and residual products between the maternal and fetal bloodstreams and is a key determinant of fetal exposure to xenobiotics from the mother. To study the disposition of substances through the placenta, various experimental models are used, especially the perfused placenta, placental villi explants, and cell lineage models. In this context, nanotechnology, an area of study that is on the rise, enables the creation of particles on nanometric scales capable of releasing drugs aimed at specific tissues. An important reason for furthering the studies on transplacental transfer is to explore the potential of nanoparticles (NPs), in new delivery strategies for drugs that are specifically aimed at the mother, the placenta, or the fetus and that involve less toxicity. Due to the fact that the placental barrier is essential for the interaction between the maternal and fetal organisms as well as the possibility of NPs being used in the treatment of various pathologies, the aim of this review is to present the main experimental models used in studying the maternal-fetal interaction and the action of NPs in the placental environment.

Trophoblast function is altered by decidual factors in gestational-dependant manner

Inadequate implantation and placentation is associated with miscarriage and placental insufficiency. The decidual environment is thought to regulate trophoblast invasion, however this is poorly defined in humans. We aimed to determine the effect of decidualization on trophoblast function. In vitro decidualized primary human endometrial stromal cells (HESC) significantly enhanced first-trimester extravillous trophoblast (EVT) (6-8-weeks gestation) adhesion, outgrowth/invasion. In EVTs from 10 to 12-weeks gestation this effect was absent (adhesion, invasion) or reversed (outgrowth). HESC conditioned media had no effect on trophoblast MMP9 production/activity. Decidualization regulated EVT function in a gestational-dependent manner. This study highlights the importance of trophoblast-decidual synchrony.

The increased level of Tspan5 in villi suggests more proliferation and invasiveness of trophoblasts in tubal pregnancy

OBJECTIVE

This study was to determinate the expression of Tspan5 in tubal ectopic implantation sites and to explore the correlation of the expressive level of Tspan5 at maternal-fetal interface and the occurrence of tubal ectopic pregnancy.

STUDY DESIGN

This is a retrospective study. Trophoblastic and endometrial tissues were collected from tubal ectopic pregnancy(Total of 40), and intrauterine pregnancy(Total of 41), who had voluntary abortion, non-pregnancy women(Total of 12), who recieved an diagnostic uterine curettage before IVF-ET for male infertility. All samples were collected from women aged 23-40 years, from February 2012 to January 2014. Results 1. In human villi Tspan5 was primarily located in cytoplasm and on the surfaces of cytotroblasts(CTs) and extravillous trophoblast(EVCTs). The intensity of Tspan5 in tubal pregnancy was significantly higher than that in normal intrauterine pregnancy, showing significant differences (Mean of IOD:109.39 ± 61.84 Vs. 89.04 ± 36.44;t = 2.33, P = 0.023). 2. In human deciduas of intrauterine pregnancy or endometrium of tubal pregnancy and non-pregnancy Tspan5 expressed in cytoplasm and membrane of glandular epithelial cells. The expressive level of this protein was increased in tubal pregnancy than that in intrauterine pregnancy and non-pregnancy(Mean of IOD:144.18 ± 106.22 Vs. 93.43 ± 67.10, P = 0.037; 144.18 ± 106.22 Vs. 88.56 ± 33.24, P = 0.018).

CONCLUSION

Our study indicated that the trophoblasts in tubal pregnancy showed more proliferative and invasive characteristics. Dysregulation of Tspan5 in decidual microenvironment may relate to the retention of embryo in fallopian tube.

SUPPORT

This study was Supported by Science and Technology Planning Project of Guangdong Province.

Decidual ACVR2A regulates extravillous trophoblast functions of adhesion, proliferation, migration and invasion in vitro

Decidual stromal cells form the largest proportion of maternal cells at the maternal-fetal interface. Our aim was to investigate the role of the pre-eclampsia associated decidual activin receptor, ACVR2A, in regulating trophoblast functions at this interface. St-T1b and HTR-8/SVneo cell lines were used to model decidual stromal and trophoblast cells respectively. St-T1b conditioned medium inhibited HTR-8/SVneo adhesion, proliferation, migration and invasion; all effects that were attenuated by decidual ACVR2A siRNA transfection. These findings suggest that altered decidual ACVR2A expression perturbs the maternal-fetal crosstalk involved in regulating trophoblast function at the interface, which may affect placentation and lead to pre-eclampsia.

Invasive trophoblast promote stromal fibroblast decidualization via Profilin 1 and ALOX5

During the establishment of pregnancy, extravillous trophoblast (EVT) must invade into the uterine decidua to facilitate decidual artery remodelling to create the placental blood supply. The local decidual environment is thought to regulate trophoblast invasion, however these interactions are poorly defined in humans. Recent evidence in women suggests impaired decidualization is associated with miscarriage and preeclampsia. Primary human endometrial stromal cells (HESC) and first trimester extravillous trophoblast (EVTs) were used to assess the effect of EVT-secreted factors on HESC decidualization, adhesion, proliferation and migration. We determined the role of profilin (PFN)1, an EVT-secreted factor, on HESC function and identified a downstream target of PFN1. EVT-secreted factors induced HESC decidualization and enhanced decidualized HESC adhesion, proliferation and migration. Recombinant PFN1 enhanced methoxyprogesterone acetate-induced HESC decidualization and proliferation. PFN1 down-regulated the expression of lipoxygenase arachidonate 5-lipoxygenase (ALOX5) in HESC and THP-1 macrophages. ALOX5 localised to decidual cells and CD68+macrophages in 1^st trimester decidua. This study demonstrated that EVT secretions, including PFN1, enhanced HESC decidualization and motility. This study has identified a new pathway that facilitates appropriate decidualization during the establishment of pregnancy.

Decrease in Expression of HOXA10 in the Decidua After Embryo Implantation Promotes Trophoblast Invasion

An important step toward successful pregnancy involves invasion of the trophoblast cells into the decidua for placentation. Herein, we show that in the human and baboon decidua HOXA10 expression is downregulated after implantation and that this reduction is most prominent in the decidual cells juxtaposed to the invading placental villi. The supernatants derived from HOXA10-depleted human decidual cells increase the invasiveness of the trophoblast cell lines ACH-3P and JEG3 in vitro; this increase is due to higher expression and activity of matrix metalloproteases (MMPs) and reduced expression of tissue inhibitors of MMPs in both the cell lines. The proinvasive ability of HOXA10-depleted decidual cells is due to increased levels and secretion of leukemia inhibitor factor (LIF) and interleukin (IL)-6. Both these cytokines individually promote invasion of ACH-3P and JEG3 cell by increasing the activities of MMPs and decreasing mRNA levels of TIMPs. Finally, we demonstrate that the supernatants derived from HOXA10-depleted decidual cell-phosphorylated STAT3 (Tyr 705) and knocking down STAT3 in ACH-3P and JEG3 cells restrained the invasion mediated by supernatants derived from HOXA10-depleted decidual cells. These results imply that STAT3 activity is essential and sufficient to promote invasion in response to downregulation of HOXA10 in decidual cells. We propose that downregulation of HOXA10 in the decidual cells promotes the expression of LIF and IL-6, which, in a paracrine manner, activates STAT3 in the trophoblast cells, leading to an increase in MMPs to facilitate invasion.

[Methyltransferase inhibitor BIX01294 promotes the migration and inhibits decidualization of mouse uterine stromal cells in vitro]

OBJECTIVE

To investigate the effect of BIX01294 (BIX), a methyltransferase inhibitor, on the migration and decidualization of the stromal cells in mouse uterus.

METHODS

Mouse endometrial stromal cells were isolated and cultured from the uterus of pregnant mice on day 3.5 of gestation. The migration and decidualization of mouse endometrial stromal cells treated with BIX at different concentrations were observed with wound healing assay and real-time PCR.

RESULTS

The migration distance of mouse endometrial stromal cells increased as the BIX concentration increased within the range below 15 µmol/L. Compared with the control cells, the cells treated with BIX (15 µmol/L) showed significantly increased migration distances, but increasing BIX concentration to 20 µmol/L did not further increase the cell migration distance and began to cause cell death. Compared with the control cells, the BIX-treated stromal cells exhibited significantly down-regulated expression of Ehmt2 mRNA, and 15 µmol/L BIX caused inhibition of decidualization in the stromal cells.

CONCLUSION

Within a defined concentration range, BIX promotes the migration and inhibits decidualization of mouse uterine stromal cells by inhibiting the expression of Ehmt2 mRNA.

Interleukin-11 up-regulates endoplasmic reticulum stress induced target, PDIA4 in human first trimester placenta and in vivo in mice

Interleukin (IL)11 is a crucial factor for human trophoblast function and placentation. Elevated levels are associated with pregnancy complications including preeclampsia, intrauterine growth restriction (IUGR) and preterm birth. However, the regulation of IL11 in the placenta has not been investigated. We examined the effect of pro-inflammatory cytokines IL1β and TNFα, as well as low oxygen tension (2%) on IL11 levels in first trimester placental villous explants. IL1β upregulated IL11 mRNA and protein, while TNFα and low oxygen had no effect. Using mass spectrometry, we identified protein disulfide isomerase 4 (PDIA4) in IL11-treated first trimester human placental explants (100 ng/ml, 24 h, n = 3), but not PBS control tissues. PDIA4 is a member of the PDI family, also known as endoplasmic reticulum (ER) stress protein (ERP)72. We previously identified GRP78 (a master regulator for ER stress) in human placenta for the first time and demonstrated that IL11 up-regulates GRP78 in the placenta. In this report, we demonstrated that IL11 upregulates PDIA4 protein in human placental villous tissue, HTR8-SVneo trophoblasts (cell line) and in vivo in IL11-treated mouse placenta. We aimed to determine whether IL11 upregulates other ER stress proteins in human first trimester placental villous. IL11 stimulated ERP44, but not GRP94, or PDI. Placental endoplasmic reticulum stress has been postulated in the pathophysiology of preeclampsia and IUGR, but its activation remains elusive. Together, these data suggest that IL11 could trigger an ER stress response in the placenta, which may contribute to obstetric complications such as preeclampsia.

Human extravillous trophoblast invasion: intrinsic and extrinsic regulation

During the establishment of pregnancy, a human blastocyst implants into the uterine endometrium to facilitate the formation of a functional placenta. Implantation involves the blastocyst adhering to the uterine luminal epithelium before the primitive syncytiotrophoblast and subsequently specialised cells, the extravillous trophoblast (EVT), invade into the decidua in order to engraft and remodel uterine spiral arteries, creating the placental blood supply at the end of the first trimester. Defects in EVT invasion lead to abnormal placentation and thus adverse pregnancy outcomes. The local decidual environment is thought to play a key role in regulating trophoblast invasion. Here we describe the major cell types present in the decidua during the first trimester of pregnancy and review what is known about their regulation of EVT invasion. Overall, the evidence suggests that in a healthy pregnancy almost all cell types in the decidua actively promote EVT invasion and, further, that reduced EVT invasion towards the end of the first trimester is regulated, in part, by the reduced invasive capacity of EVTs shown at this time.

Single-cell transcriptomics of the human placenta: inferring the cell communication network of the maternal-fetal interface

Organismal function is, to a great extent, determined by interactions among their fundamental building blocks, the cells. In this work, we studied the cell-cell interactome of fetal placental trophoblast cells and maternal endometrial stromal cells, using single-cell transcriptomics. The placental interface mediates the interaction between two semiallogenic individuals, the mother and the fetus, and is thus the epitome of cell interactions. To study these, we inferred the cell-cell interactome by assessing the gene expression of receptor-ligand pairs across cell types. We find a highly cell-type-specific expression of G-protein-coupled receptors, implying that ligand-receptor profiles could be a reliable tool for cell type identification. Furthermore, we find that uterine decidual cells represent a cell-cell interaction hub with a large number of potential incoming and outgoing signals. Decidual cells differentiate from their precursors, the endometrial stromal fibroblasts, during uterine preparation for pregnancy. We show that decidualization (even in vitro) enhances the ability to communicate with the fetus, as most of the receptors and ligands up-regulated during decidualization have their counterpart expressed in trophoblast cells. Among the signals transmitted, growth factors and immune signals dominate, and suggest a delicate balance of enhancing and suppressive signals. Finally, this study provides a rich resource of gene expression profiles of term intravillous and extravillous trophoblasts, including the transcriptome of the multinucleated syncytiotrophoblast.

miR-181b-5p Modulates Cell Migratory Proteins, Tissue Inhibitor of Metalloproteinase 3, and Annexin A2 During In Vitro Decidualization in a Human Endometrial Stromal Cell Line

Decidualization is essential for successful embryo implantation and is regulated by concerted actions of growth factors and hormones. More recently, microRNAs, small RNA molecules that regulate posttranscriptional gene expression, have been implicated to play a role in the decidualization process. Of these microRNAs, miR-181b-5p has been associated with decidualization but its precise role and targets are not well established. To address this gap in our knowledge, we assessed the expression of miR-181b-5p, and its target tissue inhibitor of metalloproteinase 3 (TIMP-3), during in vitro decidualization using the well-characterized human endometrial stromal cell line, t-HESC. miR-181b-5p expression was highest prior to decidualization and significantly decreased in response to decidualization stimulus. In contrast, TIMP-3 expression was absent prior to in vitro decidualization and increased during decidualization. Regulation of TIMP-3 expression by miR-181b-5p was confirmed in vitro by quantitative reverse transcription polymerase chain reaction (qRT-PCR), Western blot analysis, and 3' untranslated region reporter constructs. To identify unforeseen targets of miR-181b-5p during in vitro decidualization, t-HESC cells were transfected with pre- miR-181b-5p, and protein profiles were determined by 2-dimensional differential in-gel electrophoresis followed by matrix-assisted laser desorption-ionization time-of-flight/time-of-flight (MALDI TOF/TOF) tandem mass spectrometry. Of these proteins, several downregulated proteins associated with cell migration were identified including annexin A2, which we subsequently confirmed by qRT-PCR and Western blot analysis to be regulated by miR-181b-5p. In conclusion, miR-181b-5p is downregulated during the process of in vitro decidualization and may regulate the expression of proteins associated with cell migration including TIMP-3 and annexin A2.

Antibodies directed against annexin A2 and obstetric morbidity

Acquired and inherited thrombophilia have both been reported to be associated with an increased risk of obstetric complications in early or later stages of pregnancy. Annexin A2 (ANXA2) is strongly expressed in vascular and placental tissues and plays a crucial role in fibrinolysis. The aim of the present study was to evaluate the prevalence of antibodies directed against ANXA2 in patients with recurrent miscarriage or obstetric complications. Anti-ANXA2 antibodies (aANXA2) were detected by ELISA in the sera from 46 women with obstetric morbidity, mainly recurrent miscarriage. The cut-off value for positivity was defined as 3 standard deviations above the mean optical density (OD) obtained in the sera from 42 female blood donors. The prevalence of aANXA2 in patients and healthy individuals was 15.2% and 2.3%, respectively. A statistically significant difference was observed between the 2 groups in terms of aANXA2 IgG titers (p=0.01). The highest aANXA2 levels were observed in sera from 2 patients with recurrent miscarriage and one patient with preeclampsia. aANXA2 could play a role in thrombotic mechanisms leading to recurrent pregnancy loss and placental vascular disease. Further studies are needed to determine whether ANXA2 is critical for maintenance of placental integrity.

Fibulin-5 is upregulated in decidualized human endometrial stromal cells and promotes primary human extravillous trophoblast outgrowth

Interactions between the highly invasive trophoblasts and the maternal uterine decidual extracellular matrix (ECM) are crucial in the determination of a successful pregnancy. Fibulin-5 (FBLN5) is a member of the fibulin family that alters cell adhesive and invasive properties and is expressed in human villous cytotrophoblasts. We aimed to determine the expression and immunolocalization of FBLN5 in human first trimester decidua and examine the effect of FBLN5 in trophoblast invasion in vitro using a first trimester placental villous outgrowth assay. We demonstrated that FBLN5 mRNA expression is upregulated in response to cAMP-mediated decidualization of primary human endometrial stromal cells, although FBLN5 itself does not enhance decidualization. We reported for the first time, FBLN5 protein production in first trimester decidual cells and also co-localization to HLAG-positive EVTs in first trimester decidua. Consequently, we investigated the effects of exogenous FBLN5 on placental villous outgrowth in vitro and demonstrated that FBLN5 promotes EVT migration/invasion. This is the first study to identify FBLN5 in decidualized human endometrial stromal cells, first trimester decidua and EVT and determine a functional role for FBLN5 in human EVTs, suggesting that decidual and or EVT-derived FBLN5 regulates EVT invasion and placentation in women.

Proteomic analysis of human placental syncytiotrophoblast microvesicles in preeclampsia

Background

Placental syncytiotrophoblast microvesicles (STBM) are shed into the maternal circulation during normal pregnancy. STBM circulate in significantly increased amounts in preeclampsia (PE) and are considered to be among contributors to the exaggerated proinflammatory, procoagulant state of PE. However, protein composition of STBM in normal pregnancy and PE remains unknown. We therefore sought to determine the protein components of STBM and whether STBM protein expressions differ in preeclamptic and normal pregnancies.

Patients with PE (n = 3) and normal pregnant controls (n = 6) were recruited. STBM were prepared from placental explant culture supernatant. STBM proteins were analyzed by a combination of 1D Gel-LC-MS/MS. Protein expressions levels were quantified using spectral counts and validated by immunohistochemistry.

Results

Over 400 proteins were identified in the STBM samples. Among these, 25 proteins were found to be differentially expressed in preeclampsia compared to healthy pregnant controls, including integrins, annexins and histones.

Conclusion

STBM proteins include those that are implicated in immune response, coagulation, oxidative stress, apoptosis as well as lipid metabolism pathways. Differential protein expressions of STBM suggest their pathophysiological relevance in PE.

Electronic supplementary material

The online version of this article (doi:10.1186/1559-0275-11-40) contains supplementary material, which is available to authorized users.

Endometrial stromal cells and decidualized stromal cells: origins, transformation and functions

Decidualization of endometrium, which is characterized by endometrial stromal cell (ESC) decidualization, vascular reconstruction, immune cell recruitment, and plentiful molecule production, is a crucial step for uterus to become receptive for embryo. When implantation takes place, ESCs surround and directly interact with embryo. Decidualized stromal cells (DSCs) are of great importance in endometrial decidualization, having a broad function in regulating immune activity and vascular remodeling of uterus. DSCs are shown to have a higher metabolic level and looser cytoskeleton than ESCs. What's the origin of ESCs and how ESCs successfully transform into DSCs had puzzled scientists in the last decades. Breakthrough had been achieved recently, and many studies had elucidated some of the characters and functions of DSCs. However, several questions still remain unclear. This paper reviews current understanding of where ESCs come from and how ESCs differentiate into DSCs, summarizes some characters and functions of DSCs, analyzes current studies and their limitations and points out research areas that need further investigation.

Interferon-γ protects first-trimester decidual cells against aberrant matrix metalloproteinases 1, 3, and 9 expression in preeclampsia

Human extravillous trophoblast (EVT) invades the decidua via integrin receptors and subsequently degrades extracellular matrix proteins. In preeclampsia (PE), shallow EVT invasion elicits incomplete spiral artery remodeling, causing reduced uteroplacental blood flow. Previous studies show that preeclamptic decidual cells, but not interstitial EVTs, display higher levels of extracellular matrix-degrading matrix metalloproteinase (MMP)-9, but not MMP-2. Herein, we extend our previous PE-related assessment of MMP-2 and MMP-9 to include MMP-1, which preferentially degrades fibrillar collagens, and MMP-3, which can initiate a local proteolytic cascade. In human first-trimester decidual cells incubated with estradiol, tumor necrosis factor-α (TNF-α) significantly enhanced MMP-1, MMP-3, and MMP-9 mRNA and protein levels and activity measured by real-time quantitative RT-PCR, ELISA, immunoblotting, and zymography, respectively. In contrast, interferon γ (IFN-γ) reversed these effects and medroxyprogesterone acetate elicited further reversal. Immunoblotting revealed that p38 mitogen-activated protein kinase signaling mediated TNF-α enhancement of MMP-1, MMP-3, and MMP-9, whereas IFN-γ inhibited p38 mitogen-activated protein kinase phosphorylation. Unlike highly regulated MMP-1, MMP-3, and MMP-9, MMP-2 mRNA and protein expression was constitutive in decidual cells. Because inflammation underlies PE-associated shallow EVT invasion, these results suggest that excess macrophage-derived TNF-α augments expression of MMP-1, MMP-3, and MMP-9 in decidual cells to interfere with normal stepwise EVT invasion of the decidua. In contrast, decidual natural killer cell-derived IFN-γ reverses such TNF-α-induced MMPs to protect against PE.

The chrondroitin sulfate proteoglycan (CSPG4) regulates human trophoblast function

INTRODUCTION

Trophoblast growth and invasion of the uterine endometrium are critical events during placentation and are tightly regulated by locally produced factors. Abnormal placentation can result in early miscarriage or preeclampsia and intrauterine growth restriction, leading to impaired fetal and/or maternal health. Chondroitin sulfate proteoglycan 4 (CSPG4) is involved in cancer cell migration and invasion, processes which are critical during placentation but unlike in cancer, trophoblast invasion is highly regulated. CSPG4 expression and function in trophoblast is unknown. We determined CSPG4 expression in human first trimester placenta and implantation sites, and investigated whether CSPG4 influenced proliferation, migration and invasion of a human extravillous trophoblast (EVT) cell line (HTR8/SVneo cells) as a model for extravillous trophoblast (EVT).

METHODS AND RESULTS

Immunoreactive CSPG4 localized to EVT cells in the trophoblast shell, subpopulations of interstitial EVT cells within the decidua and cytotrophoblast cells in placental villi. In HTR8/SVneo cells, siRNA knockdown of CSPG4 stimulated proliferation and decreased migration/invasion. In primary first trimester placental villi explants two cytokines, interleukin 11 (IL11) and leukemia inhibitory factor (LIF) with known roles in trophoblast function, stimulated CSPG4 mRNA expression and immunoreactive protein in the cyotrophoblast.

DISCUSSION AND CONCLUSION

This is the first demonstration of the production and function of CSPG4 in human placentation. These data suggest that locally produced CSPG4 stimulates human EVT migration and invasion and suggests that IL11 and LIF regulate villous cytotrophoblast differentiation towards the invasive phenotype at least in part via CSPG4.

Transcriptomic signature to oxidative stress exposure at the time of embryonic genome activation in bovine blastocysts

In order to understand how in vitro culture affects embryonic quality, we analyzed survival and global gene expression in bovine blastocysts after exposure to increased oxidative stress conditions. Two pro-oxidant agents, one that acts extracellularly by promoting reactive oxygen species (ROS) production (0.01 mM 2,2'-azobis (2-amidinopropane) dihydrochloride [AAPH]) or another that acts intracellularly by inhibiting glutathione synthesis (0.4 mM buthionine sulfoximine [BSO]) were added separately to in vitro culture media from Day 3 (8-16-cell stage) onward. Transcriptomic analysis was then performed on resulting Day-7 blastocysts. In the literature, these two pro-oxidant conditions were shown to induce delayed degeneration in a proportion of Day-8 blastocysts. In our experiment, no morphological difference was visible, but AAPH tended to decrease the blastocyst rate while BSO significantly reduced it, indicating a differential impact on the surviving population. At the transcriptomic level, blastocysts that survived either pro-oxidant exposure showed oxidative stress and an inflammatory response (ARRB2), although AAPH induced higher disturbances in cellular homeostasis (SERPINE1). Functional genomics of the BSO profile, however, identified differential expression of genes related to glycine metabolism and energy metabolism (TPI1). These differential features might be indicative of pre-degenerative blastocysts (IGFBP7) in the AAPH population whereas BSO exposure would select the most viable individuals (TKDP1). Together, these results illustrate how oxidative disruption of pre-attachment development is associated with systematic up-regulation of several metabolic markers. Moreover, it indicates that a better capacity to survive anti-oxidant depletion may allow for the survival of blastocysts with a quieter metabolism after compaction.