Control Of Trophoblast Invasion Research Articles

The Role of the Placental Enzyme Indoleamine 2,3-Dioxygenase in Normal and Abnormal Human Pregnancy.

The biologically significant phenomenon that the fetus can survive immune attacks from the mother has been demonstrated in mammals. The survival mechanism depends on the fetus and placenta actively defending themselves against attacks by maternal T cells, achieved through the localized depletion of the amino acid L-tryptophan by an enzyme called indoleamine 2,3-dioxygenase. These findings were entirely unexpected and pose important questions regarding diseases related to human pregnancy and their prevention during human pregnancy. Specifically, the role of this mechanism, as discovered in mice, in humans remains unknown, as does the extent to which impaired activation of this process contributes to major clinical diseases in humans. We have, thus, elucidated several key aspects of this enzyme expressed in the human placenta both in normal and abnormal human pregnancy. The questions addressed in this brief review are as follows: (1) localization and characteristics of human placental indoleamine 2,3-dioxygenas; (2) overall tryptophan catabolism in human pregnancy and a comparison of indoleamine 2,3-dioxygenase expression levels between normal and pre-eclamptic pregnancy; (3) controlling trophoblast invasion by indoleamine 2,3-dioxygenase and its relation to the pathogenesis of placenta accrete spectrum.

Maternal-Fetal Compatibility in Recurrent Pregnancy Loss.

Nowadays, recurrent pregnancy loss (RPL) is an undesirable condition suffered by many patients of reproductive age. In this scenario, certain immune cell populations and molecules, involved in maternal-fetal compatibility, have emerged as factors related with the pathogenesis of RPL. Among them, uterine Natural Killer cells (uNKs) appear to be of great relevance. These cells are involved in numerous processes during pregnancy, such as the remodeling of uterine spiral arteries or the control of trophoblast invasion. These functions are regulated by the interactions that these cells establish with the extravillous trophoblast, mainly through their Killer Immunoglobulin-like Receptors (KIRs) and the Human Leukocyte Antigen-C (HLA-C) molecules expressed by the embryo. A high level of polymorphism has been reported for both molecules involved in this interaction, with some of the possible KIR-HLA-C combinations being associated with an increased risk of RPL. However, the complexity of the maternal-fetal interface goes beyond this, as other HLA molecules also appear to be related to this reproductive pathology. In this review, we will discuss the role of uNKs in pregnancy, as well as the polymorphisms and clinical implications of KIR-HLA-C binding. We will also address the involvement of other, different HLA molecules in RPL, and the current advice on the appropriate management of patients with 'immunological mismatch', thus covering the main aspects regarding the involvement of maternal-fetal compatibility in RPL.

Roles of tetraspanins during trophoblast development: bioinformatics and new perspectives.

Tetraspanins are a superfamily of membrane proteins found in all eukaryotic organisms. They act as scaffold molecules that regulate the traffic and function of other membrane/signaling proteins, resulting in important downstream cellular consequences. The aim of this work was to use transcriptomes and bioinformatics analysis to identify the tetraspanins (and their partners) involved in trophoblast differentiation. We built a protein-protein interaction network around tetraspanins which revealed that tetraspanins CD9, CD81, and CD82 show a specific expression during trophoblast differentiation. These proteins appeared to be interconnected and to recruit several membrane partners which include integrins, immune-related molecules, and a variety of receptors. During weeks 8 to 24, a CD9 expression trajectory was identified in extravillous trophoblasts, and a website was developed: ( https://extravillous.shinyapps.io/CD9humanEVT/ ). In conclusion, CD81 may, together with CD9 and CD82, be interconnected in controlling trophoblast invasion in the endometrium. CD9 expression trajectory in extravillous trophoblast between weeks 8 and 24 shows the involvement of CD9 in cell adhesion and migration.

Role of ARID1A in the Regulation of Human Trophoblast Migration and Invasion.

Migration and invasion of trophoblasts is critical for human placental development, trophoblastic differentiation, and pregnancy-associated diseases. AT-rich interactive domain-containing protein 1A (ARID1A), a subunit of the SWI-SNF complex, has been suggested to participate in the regulation of fertility via placental disruption in mice. However, whether ARID1A regulates human placental development and function remains unknown. Here, using human trophoblast-like JEG-3 cell line, we report that ARID1A controls trophoblast cell migration and invasion. Overexpression of ARID1A inhibits JEG-3 cell migration and invasion, whereas knockdown of ARID1A promotes migration and invasion in JEG-3 cells. Mechanistically, while ARID1A reduces JEG-3 cell migration by down-regulation of Snail transcription, it restrains JEG-3 cell invasion by binding to and destabilization of MMP-9 protein. Finally, ARID1A is apparently up-regulated in placental tissues of preeclampsia compared to that of normal pregnancies. Our results thereby imply that ARID1A acts as a critical gene in supporting the physiological function of human mature placenta.

Preimplantation factor modulates trophoblastic invasion throughout the decidualization of human endometrial stromal cells

BackgroundSuccessful human embryo implantation requires the differentiation of endometrial stromal cells (ESCs) into decidual cells during a process called decidualization. ESCs express specific markers of decidualization, including prolactin, insulin-like growth factor-binding protein-1 (IGFBP-1), and connexin-43. Decidual cells also control of trophoblast invasion by secreting various factors, such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases. Preimplantation factor (PIF) is a recently identified, embryo-derived peptide with activities at the fetal-maternal interface. It creates a favorable pro-inflammatory environment in human endometrium and directly controls placental development by increasing the human trophoblastic cells’ ability to invade the endometrium. We hypothesized that PIF’s effects on the endometrium counteract its pro-invasive effects.MethodsWe tested sPIF effect on the expression of three decidualization markers by RT-qPCR and/or immunochemiluminescence assay. We examined sPIF effect on human ESC migration by performing an in vitro wound healing assay. We analyzed sPIF effect on endometrial control of human trophoblast invasion by performing a zymography and an invasion assay.ResultsFirstly, we found that a synthetic analog of PIF (sPIF) significantly upregulates the mRNA expression of IGFBP-1 and connexin-43, and prolactin secretion in ESCs - suggesting a pro-differentiation effect. Secondly, we showed that the HTR-8/SVneo trophoblastic cell line’s invasive ability was low in the presence of conditioned media from ESCs cultured with sPIF. Thirdly, this PIF’s anti-invasive action was associated with a specifically decrease in MMP-9 activity.ConclusionTaken as a whole, our results suggest that PIF accentuates the decidualization process and the production of endometrial factors that limit trophoblast invasion. By controlling both trophoblast and endometrial cells, PIF therefore appears to be a pivotal player in the human embryo implantation process.

Role of the HLA-G immune checkpoint molecule in pregnancy

The non-classical HLA class I molecule HLA-G is expressed in trophoblasts where it contributes to maternal-fetal tolerance. HLA-G has been implicated in the control of trophoblast invasion, uterine vascular remodeling, and maintenance of a local immunosuppressive state. Understanding HLA-G biology at the maternal-fetal interface is therefore a critical issue in reproduction. In this regard, we review here: (i) the effects of HLA-G on decidual leucocytes and stromal cells, (ii) the contribution of trogocytosis in HLA-G expression on decidual cells, (iii) its interaction with the ILT2, ILT4 and KIR2DL4 receptors, (iv) the link between HLA-G polymorphism and pregnancy disorders, and (v) the expression of newly-described HLA-G isoforms at the maternal-fetal interface.

Uterine natural killer cells: from foe to friend in reproduction.

Recurrent miscarriage and pre-eclampsia are common reproductive disorders, but their causes are often unknown. Recent evidence has provided new insight into immune system influences in reproductive disorders. A subset of lymphocytes of the innate immune system known as uterine natural killer (uNK) cells are now recognized as fundamental to achieving embryo implantation and successful pregnancy, but were initially attributed a bad reputation. Indeed, immune therapies have been developed to treat the 'exaggerated' immune response from uNK cells. These treatments have been based on studies of peripheral blood natural killer (pbNK) cells. However, uNK cells and pbNK cells have different phenotypic and functional characteristics. The functions of uNK cells are closely related to their interactions with the extravillous trophoblast cells (EVTs) and spiral arteries, which underlie an essential role in regulating vascular function, controlling trophoblast invasion and promoting placental development. EVTs express MHC molecules of class I HLA-C/E/G/F, while uNK cells express, among other receptors, killer cell immunoglobulin-like receptors (KIRs) that bind to HLA-C or CD94/NKG2A inhibitory receptors, and then bind HLA-E. Associations of certain KIR/HLA-C combinations with recurrent miscarriage, pre-eclampsia, and foetal growth restriction and the interactions between uNK cells, trophoblasts and vascular cells have led to the hypothesis that uNK cells may play a role in embryo implantation. Our objective was to review the evolution of our understanding of uNK cells, their functions, and their increasingly relevant role in reproduction. Relevant literature through June 2020 was retrieved using Google Scholar and PubMed. Search terms comprised uNK cells, human pregnancy, reproductive failure, maternal KIR and HLA-C, HLA-E/G/F in EVT cells, angiogenic cytokines, CD56+ NK cells, spiral artery, oestrogen and progesterone receptors, KIR haplotype and paternal HLA-C2. This review provides key insights into the evolving conceptualization of uNK cells, from their not-so-promising beginnings to now, when they are considered allies in reproduction. We synthesized current knowledge about uNK cells, their involvement in reproduction and their main functions in placental vascular remodeling and trophoblast invasion. One of the issues that this review presents is the enormous complexity involved in studying the immune system in reproduction. The complexity in the immunology of the maternal-foetal interface lies in the great variety of participating molecules, the processes and interactions that occur at different levels (molecular, cellular, tissue, etc.) and the great diversity of genetic combinations that are translated into different types of responses. Insights into uNK cells could offer an important breakthrough for ART outcomes, since each patient could be assessed based on the combination of HLA and its receptors in their uNK cells, evaluating the critical interactions at the materno-foetal interface. However, owing to the technical challenges in studying uNK cells in vivo, there is still much knowledge to gain, particularly regarding their exact origin and functions. New studies using novel molecular and genetic approaches can facilitate the identification of mechanisms by which uNK cells interact with other cells at the materno-foetal interface, perhaps translating this knowledge into clinical applicability.

PreImplantation Factor immunohistochemical expression correlates with prostate cancer aggressiveness.

The PreImplantation Factor (PIF)-a peptide secreted by viable embryos-exerts autotrophic protective effects, promotes endometrial receptivity and controls trophoblast invasion. Synthetic PIF (sPIF) has both immune-protective and regenerative properties, and reduces oxidative stress and protein misfolding. PIF is detected by immunohistochemistry (IHC) in hyperplastic endometriotic lesions and advanced uterine cancer. sPIF reduces graft-versus-host disease while maintaining a graft-versus-leukemia effect. PIF detection in prostate cancer was assessed in 50 human prostate samples following radical prostatectomy using tumor-microarray-based IHC correlating PIF immune staining with Gleason score (GS) and cancer aggressiveness. PIF was detected in moderate-to-high risk prostate cancer (GS 4+3 and beyond, prognostic groups 3 to 5). In prostate cancer (GS (WHO Grade Group (GG)5), PIF was detected in 50% of cases; in prostate cancer (GS 4+4 GG4), PIF was observed in 62.5% of cases; in prostate cancer (GS 4+3 GG3), PIF immunostaining was observed in 57.1% of cases. In prostate cancer, (GS 3+4 GG2) and (GS 3+3 GG1) cases where PIF staining was negative to weak, membranous staining was observed in 20% of cases (staining pattern considered negative). High-grade prostate intraepithelial neoplasia PIF positive stain in 28.57% of cases (6 of 21) was observed. In contrast, PIF was not detected in normal prostate glands. Importantly, sPIF added to the PC3 cell line alone or combined with prostate cancer fibroblast feeder-cells did not affect proliferation. Only when peripheral blood mononuclear cells were added to the culture, a minor increase in cell proliferation was noted, reflecting local proliferation control. Collectively, PIF assessment could be a valuable, simple-to-use immunohistochemical biomarker to evaluate aggressiveness/prognosis in specimens from prostate cancer patients.

Indoleamine 2,3-dioxygenase and trophoblast invasion in caesarean scar pregnancy: Implications for the aetiopathogenesis of placenta accreta spectrum

Immunohistochemical localisation of indoleamine 2,3-dioxygenase was studied in order to better understand the pathophysiology of placenta accreta spectrum. In the decidua staining for indoleamine 2,3-dioxygenase was found in the glandular epithelium with some additional positive cells. Extravillous cytotrophoblast invasion was present in the myometrium which was not covered by the decidual tissue whereas myometrial invasion of cytotrophoblasts was absent where this tissue lay deep to decidua. These results suggest that indoleamine 2,3-dioxygenase expression in the decidua may normally control trophoblast invasion and absence of its expression where decidua is absent may be involved in the pathogenesis of the over-invaded placenta.

The m6A demethylase ALKBH5 controls trophoblast invasion at the maternal-fetal interface by regulating the stability of CYR61 mRNA.

N6-Methyladenosine (m6A) is the most prevalent internal modification in mammalian mRNAs. Although m6A is important in many biological processes, its roles in the placenta are unclear.Methods: Levels of global mRNA m6A methylation and ALKBH5 expression in recurrent miscarriage (RM) patients were determined using quantitative reverse transcription-PCR (qRT-PCR), m6A RNA methylation quantification, and immunohistochemical methods. Using ALKBH5 overexpression and knockdown methods, we determined the role of ALKBH5 in trophoblast invasion at the maternal interface through trophoblasts and an extravillous explant culture experiments. Furthermore, the regulation of CYR61 by ALKBH5 was explored by RNA-sequencing coupled with methylated RNA immunoprecipitation.Results: We found that the level of global mRNA m6A methylation was significantly decreased in placental villous tissue from RM patients, while ALKBH5 expression was specifically unregulated. Furthermore, we demonstrated that ALKBH5 knockdown in human trophoblast promoted trophoblast invasion. Conversely, overexpression of ALKBH5 inhibited cell invasion. ALKBH5 knockdown promoted trophoblast invasion in villous explant culture experiments, while overexpression of ALKBH5 repressed these effects. Furthermore, we clarified that ALKBH5 inhibited trophoblast invasion by regulating CYR61 mRNA stability, and this RNA regulation is m6A dependent. Mechanistic analyses showed that decreased ALKBH5 in trophoblast increased the half-life of CYR61 mRNA and promoted steady-state CYR61 mRNA expression levels.Conclusions: We elucidated the functional roles of ALKBH5 and mRNA m6A methylation in trophoblast and identified a novel RNA regulatory mechanism, providing a basis for further exploration of broad RNA epigenetic regulatory patterns in RM diseases.

Lectin histochemical analysis of uterine natural killer cells in normal, hydatidiform molar and invasive molar pregnancy.

Uterine natural killer (uNK) cells have been hypothesized to serve a role in controlling trophoblast invasion and proliferation. The aim of the present study was to identify the distribution and number of uNK cells in normal pregnancy (NP), partial mole (PM), complete mole (CM) and invasive mole (IM). uNK cells were detected using dolichos biflorus agglutinin lectin immunohistochemistry in decidual and villous tissues from early NP (n=15), late NP (n=15), PM (n=22), CM (n=20) and IM (n=10). A scaled eye piece was used for cell counting to obtain semi-quantitative results. It was revealed that uNK cells were mainly located in the uterine deciduas of early NP. As pregnancy progressed, the number of decidual uNK cells significantly decreased. Decidual uNK cells of PM, CM and IM were located near blood vessel endothelial cells. No significant differences were detected with respect to the numbers of decidual uNK between early NP and PM. However, the number of decidual uNK cells was significantly reduced in CM and IM compared with early NP. The populations of decidual uNK cells were not significantly different between CM and IM. No uNK cells were detected in the villi of PM, CM or IM. The decrease of decidual uNK cells in late NP, CP and IM, compared with early NP, suggested that uNK cells served an important role in controlling trophoblast invasion and proliferation.

Adiponectin limits differentiation and trophoblast invasion in human endometrial cells.

Successful human embryo implantation requires a proper differentiation of endometrial stromal cells (ESCs) into decidual cells, during a process called decidualization. ESCs express specific molecules, such as prolactin, insulin-like growth factor-binding protein-1 (IGFBP-1) and connexin-43. Decidual cells are also involved in the control of trophoblast invasion, by secreting various factors, such as matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs). Adiponectin is an adipokine with insulin-sensitizing, anti-inflammatory and anti-proliferative effects. At the embryo-maternal interface, adiponectin promotes differentiation and invasion of human trophoblastic cells. We hypothesize that the effects of adiponectin on endometrium could counteract its pro-invasive effects previously described in the human trophoblast. In this context, we have firstly demonstrated that adiponectin downregulates IGFBP-1 and connexin-43 mRNA expressions, as well as prolactin secretion in ESCs, suggesting an anti-differentiative effect of adiponectin. Secondly, we found that invasive capacities of trophoblastic cell line HTR-8/SVneo are reduced in the presence of conditioned media from ESC cultured in the presence of adiponectin. Adiponectin's anti-invasive action is associated with a decreased activity of MMP-2 and MMP-9, and an increased TIMP-3 mRNA expression in ESCs. Finally, adiponectin receptors (ADIPOR1 and ADIPOR2) knockdown abolishes the anti-differentiative and anti-invasive effects of adiponectin in human ESCs. Altogether, our results suggest that adiponectin reduces the decidualization process and inversely induces the production of endometrial factors that limit trophoblast invasion. Thus, through a dual control in trophoblast and endometrial cells, adiponectin appears as a pivotal actor of the embryo implantation process.

Prokineticin1 and pregnancy

Prokineticin 1 (PROK1), also called EG-VEGF, is a peptide of 86 amino acids with multiple biological functions. PROK1 acts via two G-protein coupled receptors: PROKR1 PROKR2. PROK1 is highly expressed in the placenta. This article reports the expression and the role of PROK1 during normal and pathological pregnancies: (i) during early pregnancy, PROK1 exhibits a peak of placental expression shortly before the establishment of the feto-maternal circulation; (ii) its receptors, PROKR1 PROKR2 are highly expressed in human placenta; (iii) its expression is increased by hypoxia; (iv) PROK1 inhibits extravillous trophoblasts migration and invasion and increases their proliferation and survival; (v) PROK1 is also a pro-angiogenic placental factor that increases microvascular placental endothelial cells proliferation, migration, invasion, and permeability. Circulating PROK1 levels are five times higher in pregnant women during the first trimester compared to the second and third trimesters. Also, its serum levels are higher in patients with preeclampsia (PE) and in patients with isolated intra-uterine growth restriction (IUGR). In mice, maintaining high level of PROK1 beyond its normal period of production (>10.5dpc) reproduces symptoms of PE. To date, our results demonstrated that PROK1 is a central factor of human placentation with direct roles both in the control of trophoblast invasion and villous growth. Thus, a failure in the expression of PROK1 and/or its receptor during pregnancy may contribute to the development of PE and/or IUGR. Besides theses original findings, we also report a direct role of this factor in parturition.

Alteration of Pituitary Tumor Transforming Gene-1 Regulates Trophoblast Invasion via the Integrin/Rho-Family Signaling Pathway.

Trophoblast invasion ability is an important factor in early implantation and placental development. Recently, pituitary tumor transforming gene 1 (PTTG1) was shown to be involved in invasion and proliferation of cancer. However, the role of PTTG1 in trophoblast invasion remains unknown. Thus, in this study we analyzed PTTG1 expression in trophoblasts and its effect on trophoblast invasion activity and determined the mechanism through which PTTG1 regulates trophoblast invasion. Trophoblast proliferation and invasion abilities, regardless of PTTG1 expression, were analyzed by quantitative real-time polymerase chain reaction, fluorescence-activated cell sorting analysis, invasion assay, western blot, and zymography after treatment with small interfering RNA against PTTG1 (siPTTG1). Additionally, integrin/Rho-family signaling in trophoblasts by PTTG1 alteration was analyzed. Furthermore, the effect of PTTG1 on trophoblast invasion was evaluated by microRNA (miRNA) mimic and inhibitor treatment. Trophoblast invasion was significantly reduced through decreased matrix metalloproteinase (MMP)-2 and MMP-9 expression when PTTG1 expression was inhibited by siPTTG1 (p < 0.05). Furthermore, knockdown of PTTG1 increased expression of integrin alpha 4 (ITGA4), ITGA5, and integrin beta 1 (ITGB1); otherwise, RhoA expression was significantly decreased (p < 0.05). Treatment of miRNA-186-5p mimic and inhibitor controlled trophoblast invasion ability by altering PTTG1 and MMP expression. PTTG1 can control trophoblast invasion ability via regulation of MMP expression through integrin/Rho-family signaling. In addition, PTTG1 expression and its function were regulated by miRNA-186-5p. These results help in understanding the mechanism through which PTTG1 regulates trophoblast invasion and thereby implantation and placental development.

Natural Killer (NK) Cell Receptors and their Role in Pregnancy and Abortion

Existing data suggest that decidual Natural Killer Cells (dNK CD3-CD56brightCD16dim/-) are important in early pregnancy (local response to pathogens, control of trophoblast invasion, uterine vascular remodeling), while in ongoing pregnancy they contribute to the acceptance of the embryo through various immunoregulatory mechanisms. In the so-called alloimmune abortions, CD3-CD56brightCD16dim/-NK cells are decreased in favor of CD3-CD56dimCD16bright NK cells, which are toxic for trophoblast. Most of the activating and inhibitory receptors regulating dNK function belong to the highly polymorphic KIR (Killer Immunoglobulin-like) family. KIRs have as ligands the only HLA molecules expressed on extravillous cytotrophoblast (HLA-C, -E, -G). The interactions of maternal KIR receptors with fetal HLA-C molecules provide an immunogenetic allorecognition system. If inhibitory KIRs recognize their specific ligands, they inhibit dNK activation for trophoblast damage. Otherwise, dNK are allowed to develop anti-trophoblast activity. Given the differences in both the KIR repertoire and the HLA-C allotypes among unrelated individuals, each pregnancy presents a different combination of maternal KIR receptors on dNK and self and non-self HLA-C allotypes on trophoblast. Current studies provide evidence for differences between the combinations arising in successful pregnancies to those found in cases of abortions.

Maternal T cell responses in pregnancy

mucosa undergoes hundreds of remodelling cycles frommenarche to menopause and uNK and other uterine ILCs (uILC) may regulate tissue homeostasis. During gestation, uNK cells control trophoblast invasion, remodel uterine arteries and regulate fetal growth, thus contributing to laying the foundation in utero for a healthy adult life. uNK cells are indeed at the boundary between two genetically different individuals and combinations of maternal variable NK receptors (KIR) and trophoblast HLA-C are linked to both fetal growth and pregnancy complications underpinned by poor placentation. We will discuss our recent data on human and mouse uILCs.

Biopsy techniques to study the human placental bed

BackgroundThe physiologic transformation of uterine spiral arteries in the human placental bed is essential for a healthy pregnancy. Failure of this transformation due to deficient trophoblast invasion is widely believed to underlie pregnancy complications such as preeclampsia, foetal growth restriction, miscarriage and preterm labour. Understanding of invasive behaviour and remodelling properties of trophoblasts in the uterine wall is essential in elucidating the aetiology of these pregnancy complications. However, there is a lack of satisfactory specimens of the placental bed to enhance our knowledge on the mechanisms that control trophoblast invasion. Several techniques can be used to obtain biopsies from the placental bed and sample handling can be executed differently depending on the research question. MethodsThis systematic review provides an overview of all studies investigating the placental bed and sampling techniques used. Papers that described surgical techniques, specimen handling, complications and/or success rate of the placental bed biopsy procedures were included. Placental bed biopsies are an essential and feasible technique to study abnormalities in the placental bed associated with pregnancy complications. ResultsDepending on the technique used the likelihood of sampling a spiral artery and trophoblast from the placental bed is 51%–78% per case, without significant complications. ConclusionsCaution is needed when interpreting data if the placental bed is subjected to labour. We propose a uniform sampling technique and conservation protocol for the study of the placental bed and provide tools for selection of the appropriate technique for future placental bed collections.

Functional Antagonism between High Temperature Requirement Protein A (HtrA) Family Members Regulates Trophoblast Invasion

Human trophoblast invasion of decidualized endometrium is essential for placentation and is tightly regulated and involves trophoblast-decidual cell interaction. High temperature requirement A4 (HtrA4) is a secreted serine protease highly expressed in the invasive extravillous trophoblasts that invade decidua. In contrast, both HtrA1 and HtrA3 have been shown to inhibit trophoblast invasion. Here we provide evidence that decidua-secreted HtrA1 and HtrA3 antagonize HtrA4-mediated trophoblast invasion. We demonstrated that HtrA1 and HtrA3 interact with and degrade HtrA4 and thereby inhibit trophoblast-like JAR cell invasion. Specifically, HtrA1 and HtrA3 expression is up-regulated under decidualization conditions in endometrial stromal and epithelial cells, T-HESCs and Ishikawa cells, respectively. Conditioned media from these two cell lines after decidualization treatment suppress HtrA4-expressing JAR cell invasion in an HtrA1- or HtrA3-dependent manner. Co-culture of the HtrA4-expressing JAR cells with decidualization stimuli-treated T-HESC or Ishikawa monolayer also impairs JAR cell invasion, which can be reversed by HtrA1 or HtrA3 knockdown, supporting that HtrA1 and HtrA3 are crucial for trophoblast-decidual cell interaction in the control of trophoblast invasion. Our study reveals a novel regulatory mechanism of trophoblast invasion through physical and functional interaction between HtrA family members.

Progesterone-induced blocking factor differentially regulates trophoblast and tumor invasion by altering matrix metalloproteinase activity.

Invasiveness is a common feature of trophoblast and tumors; however, while tumor invasion is uncontrolled, trophoblast invasion is strictly regulated. Both trophoblast and tumor cells express high levels of the immunomodulatory progesterone-induced blocking factor (PIBF), therefore, we aimed to test the possibility that PIBF might be involved in invasion. To this aim, we used PIBF-silenced or PIBF-treated trophoblast (HTR8/Svneo, and primary trophoblast) and tumor (HT-1080, A549, HCT116, PC3) cell lines. Silencing of PIBF increased invasiveness as well as MMP-2,-9 secretion of HTR8/SVneo, and decreased those of HT-1080 cells. PIBF induced immediate STAT6 activation in both cell lines. Silencing of IL-4Rα abrogated all the above effects of PIBF, suggesting that invasion-related signaling by PIBF is initiated through the IL-4Rα/PIBF-receptor complex. In HTR-8/SVneo, PIBF induced fast, but transient Akt and ERK phosphorylation, whereas in tumor cells, PIBF triggered sustained Akt, ERK, and late STAT3 activation. The late signaling events might be due to indirect action of PIBF. PIBF induced the expression of EGF and HB-EGF in HT-1080 cells. The STAT3-activating effect of PIBF was reduced in HB-EGF-deficient HT-1080 cells, suggesting that PIBF-induced HB-EGF contributes to late STAT3 activation. PIBF binds to the promoters of IL-6, EGF, and HB-EGF; however, the protein profile of the protein/DNA complex is different in the two cell lines. We conclude that in tumor cells, PIBF induces proteins, which activate invasion signaling, while-based on our previous data-PIBF might control trophoblast invasion by suppressing proinvasive genes.

Mucins Help to Avoid Alloreactivity at the Maternal Fetal Interface

During gestation, many different mechanisms act to render the maternal immune system tolerant to semi-allogeneic trophoblast cells of foetal origin, including those mediated via mucins that are expressed during the peri-implantation period in the uterus. Tumour- associated glycoprotein-72 (TAG-72) enhances the already established tolerogenic features of decidual dendritic cells with the inability to progress towards Th1 immune orientation due to lowered interferon (IFN)-γ and interleukin (IL)-15 expression. Mucine 1 (Muc 1) supports alternative activation of decidual macrophages, restricts the proliferation of decidual regulatory CD56+ bright natural killer (NK) cells, and downregulates their cytotoxic potential, including cytotoxic mediator protein expression. Removing TAG-72 and Muc 1 from the eutopic implantation site likely contributes to better control of trophoblast invasion by T cells and NK cells and appears to have important immunologic advantages for successful implantation, in addition to mechanical advantages. However, these processes may lead to uncontrolled trophoblast growth after implantation, inefficient defence against infection or tumours, and elimination of unwanted immunocompetent cells at the maternal-foetal interface. The use of mucins by tumour cells to affect the local microenvironment in order to avoid the host immune response and to promote local tumour growth, invasion, and metastasis confirms this postulation.