Control Of Trophoblast Invasion Research Articles

Alloreactivity-Based Medical Conditions

Alloreactivity is a response of the immune system to individual antigenic differences within species. These responses in general occur following exposure to alloantigens as a consequence of medical intervention (such as transfusion or tissue transplantation) or during pregnancy. Responses to alloantigens form a basis of a broad spectrum of medical conditions, such as graft rejection, graft versus host disease, reaction to blood (products), or biopharmaceuticals and fetal and neonatal diseases (thrombocytopenia, hemolytic anemia, hemochromatosis, biliary atresia, and glomerulopathy). On the other hand, normal pregnancies are often accompanied by strongly tolerogenic responses to fetal alloantigens. Diverse immunologic components, including T cells, antibodies (B cells), and NK cells, promote alloreactivity, and this complexity makes the pathogenesis and tolerogenesis of these conditions distinct and unique. This special issue contains seven manuscripts touching on various aspects of alloreactivity in medicine. Blocking CD40-CD40L interaction can induce acceptance of cardiac allografts. However, the blockade is less efficient under inflammatory conditions. In “Glucocorticoid-induced TNFR-related protein reverses cardiac allograft acceptance induced by CD40-CD40L blockade,” Krill et al. demonstrate that stimulation of GITR (a cell surface molecule displayed by effector and regulatory T cells) can initiate cardiac graft rejection irrespective of the presence or absence of CD40-CD40L blockade, defining thus at least one possible molecular mechanism of resistance to CD40-CD40L suppression. The balance between the effector and regulatory T cells is critical for development of graft-specific immune responses in general. Franzese et al. review the usefulness of this balance in predicting or establishing the diagnosis of graft rejection in “Regulatory T cells in the immunodiagnosis and outcome of kidney allograft rejection.” Allogeneic hematopoietic stem cell transplantation is used for treatment of autoimmune diseases, multiple organ transplantation, consequences of supralethal irradiation and advanced malignancies and other serious conditions refractory to conventional methods. In “New allogeneic hematopoietic cell transplantation method: hematopoietic cell transplantation plus thymus transplantation for intractable diseases,” Hosaka demonstrates that allogeneic hematopoietic stem cell transplantation combined with the same donor thymus transplantation has a superior effect producing more efficient T cell function and reduced graft versus host disease. Redzovic et al., in “Mucins help to avoid alloreactivity at the maternal fetal interface,” review roles of mucin-1 and tumor associated glycoprotein-72 in regulating immune responses. Parallels are drawn between the ability of these molecules to promote tumor growth, invasion, and metastasis and to prevent trophoblast invasion. Removing glycoproteins TAG-72 and Muc 1 from the eutopic implantation site likely contributes to better control of trophoblast invasion by T cells and NK cells. This enables tolerance to paternal antigens of the fetus and normal course and outcome of the pregnancy. Three manuscripts explore distinct aspects of alloantibody formation. Preformed donor HLA class I-specific antibodies are a risk factor for rejection of kidney, heart, and lung grafts, but the role of these antibodies is less clear in liver transplantation, where rejection rates are lower. Yoshizawa et al., in “Significance of semiquantitative assessment of preformed donor-specific antibody using luminex single bead assay in living related liver transplantation,” describe a quantitative assay for donor specific antibodies that has a predictive value for living donor liver transplantation. In “Nuclear antigens and auto/alloantibody responses: friend or foe in transplant immunology,” Nakano et al. review current thinking about the role of nuclear antigens and antibodies specific for nuclear antigens in initiation and regulation of immune responses and graft rejection. Finally, transfusion of allogeneic red blood cells may in some recipients induce alloantibodies. Tatari-Calderone et al. in “The association of CD81 polymorphisms with alloimmunization in sickle cell disease” suggest that genetic elements in the gene encoding B-cell molecule CD81 may be predictive markers of alloimmunization. The huge breadth of the field of alloreactivity-based medical conditions allows the special issue only to scratch under the surface of any specific topic. Our hope, however, is that this issue will help raise awareness of the immunological basis of these conditions and will foster further efforts to better understand their pathogenesis. Ultimately, this should help us design better treatments or prevent the development of these medical conditions altogether.

Effects of local decidua on trophoblast invasion and spiral artery remodeling in focal placenta creta – An immunohistochemical study

ObjectivesPlacenta creta is an increasingly prevalent cause of maternal morbidity/mortality. Decidua is at least focally defective and extravillous trophoblast (EVT) may be abnormal. The study aims to compare differences in migratory trophoblast and spiral artery remodeling between areas with and without decidua at the placental implantation site. Study designSixteen (12 creta, 4 non-creta) caesarean hysterectomy specimens were studied immunohistochemically. Invasive EVT and multinucleate trophoblast giant cells (MTGC) were quantified; confluent EVT (>5 opposed EVTs) and spiral artery remodeling were assessed semi-quantitatively. ResultsIn 6 cases, placenta creta was focal. Compared to placenta creta with local decidua, cases without local decidua had increased interstitial EVT cells (×200 field) (SEM 45.6 [4.9] vs. 80.5 [3.9], p < 0.0001), fewer multinucleate trophoblast giant cells (expressed as a percentage of total EVT) (0.8 [0.3] vs. 31.5 [2.2]% p < 0.0001) and EVT was more confluent (p < 0.0001). In contrast, placenta creta cases with local decidua had a greater degree of spiral artery remodeling (mean remodeling score 1.65 [0.07] vs. 1.13 [0.05], p < 0.0001) associated with increased intramural trophoblast (p = 0.0008). The only difference between placenta creta with local decidua and normal placentation cases was an increased number of interstitial EVT cells in creta cases (45.6 [4.9] vs. 24.8 [3.2], p = 0.04). ConclusionsNumbers of interstitial EVT are increased in placenta creta, more so in cases without local decidua. Despite this spiral artery modeling is reduced in placenta creta cases with no decidua. The results emphasize the crucial role of decidua in control of trophoblast invasion and spiral artery remodeling.

EG-VEGF controls placental growth and survival in normal and pathological pregnancies: case of fetal growth restriction (FGR).

Identifiable causes of fetal growth restriction (FGR) account for 30 % of cases, but the remainders are idiopathic and are frequently associated with placental dysfunction. We have shown that the angiogenic factor endocrine gland-derived VEGF (EG-VEGF) and its receptors, prokineticin receptor 1 (PROKR1) and 2, (1) are abundantly expressed in human placenta, (2) are up-regulated by hypoxia, (3) control trophoblast invasion, and that EG-VEGF circulating levels are the highest during the first trimester of pregnancy, the period of important placental growth. These findings suggest that EG-VEGF/PROKR1 and 2 might be involved in normal and FGR placental development. To test this hypothesis, we used placental explants, primary trophoblast cultures, and placental and serum samples collected from FGR and age-matched control women. Our results show that (1) EG-VEGF increases trophoblast proliferation ([(3)H]-thymidine incorporation and Ki67-staining) via the homeobox-gene, HLX (2) the proliferative effect involves PROKR1 but not PROKR2, (3) EG-VEGF does not affect syncytium formation (measurement of syncytin 1 and 2 and β hCG production) (4) EG-VEGF increases the vascularization of the placental villi and insures their survival, (5) EG-VEGF, PROKR1, and PROKR2 mRNA and protein levels are significantly elevated in FGR placentas, and (6) EG-VEGF circulating levels are significantly higher in FGR patients. Altogether, our results identify EG-VEGF as a new placental growth factor acting during the first trimester of pregnancy, established its mechanism of action, and provide evidence for its deregulation in FGR. We propose that EG-VEGF/PROKR1 and 2 increases occur in FGR as a compensatory mechanism to insure proper pregnancy progress.

Specific decidual CD14+ cells hamper cognate NK cell proliferation and cytolytic mediator expression after mucin 1 treatment in vitro

Mucin 1 (MUC1) forms a glycocalyx on the surface of decidual epithelial cells that needs to be removed for successful embryo attachment. We investigated whether MUC1 affects human early pregnancy decidual CD14+ cells and their interactions with cognate decidual natural killer (NK) cells. FITC-dextran internalisation, surface and intracellular antigen levels, and proliferation of CD14+ and/or CD56+ cells were analysed by flow cytometry. Magnetic separation was used to purify CD56+ and CD14+ cells. Uncultured CD14+ cells expressed a negligible percentage of CD1a and CD83 molecules. They expressed lower levels of CD16, and higher levels of endocytic mannose receptors (MR), dendritic cell-specific intercellular adhesion molecule grabbing non-integrin (DC-SIGN), proinflammatory chemokine CC receptor 5 (CCR5), and CD163 receptor, than their peripheral blood counterparts. Lipopolysaccharide stimulation did not affect FITC-dextran internalisation in CD14+ cells. MUC1 bound and internalised, in a dose-dependent manner, the carbohydrate recognition domain of MR, increasing the decoy IL-1 receptor type II and decreasing IL-15 expression in CD14+ cells. In the presence of MUC1-treated macrophages, the expression levels of the proliferation and cytotoxic mediators (perforin, Fas ligand and TNF-related activation-induced ligand or TRAIL) was attenuated, while that of the anti-inflammatory chemokine CCL17 was increased, in NK cells compared with untreated macrophages. In conclusion, MUC1 supports the alternative activation of tissue-specific CD14+ cells, and may restrict proliferation of NK cells and regulate their content of cytotoxic mediators. Based on the experiments with first-trimester decidual cells in vitro, we conclude that removing MUC1 from decidual tissue might help control trophoblast invasion by NK cells.

Progesterone-induced blocking factor (PIBF) controls trophoblast invasion

Progesterone-induced blocking factor (PIBF) controls trophoblast invasion

Inhibition of Histone Deacetylase Activity in Human Endometrial Stromal Cells Promotes Extracellular Matrix Remodelling and Limits Embryo Invasion

Invasion of the trophoblast into the maternal decidua is regulated by both the trophoectoderm and the endometrial stroma, and entails the action of tissue remodeling enzymes. Trophoblast invasion requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins and in turn, decidual cells express tissue inhibitors of MMPs (TIMPs). The balance between these promoting and restraining factors is a key event for the successful outcome of pregnancy. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. In this study we analyze the effect of histone acetylation on the expression of tissue remodeling enzymes and activity of human endometrial stromal cells (hESCs) related to trophoblast invasion control. Treatment of hESCs with the HDAC inhibitor trichostatin A (TSA) increased the expression of TIMP-1 and TIMP-3 while decreased MMP-2, MMP-9 and uPA and have an inhibitory effect on trophoblast invasion. Moreover, histone acetylation is detected at the promoters of TIMP-1 and TIMP-3 genes in TSA-treated. In addition, in an in vitro decidualized hESCs model, the increase of TIMP-1 and TIMP-3 expression is associated with histone acetylation at the promoters of these genes. Our results demonstrate that histone acetylation disrupt the balance of ECM modulators provoking a restrain of trophoblast invasion. These findings are important as an epigenetic mechanism that can be used to control trophoblast invasion.

Dynamic alterations in integrin α4 expression by hypoxia are involved in trophoblast invasion during early implantation

Implantation of the blastocyst into the maternal endometrium is mediated by a population of well-differentiated primary cells of the placenta known as trophoblasts, which grow in an invasive and destructive fashion similar to tumor cells. Interactions between the endometrium and trophoblasts are regulated by a coordinated interplay of extracellular matrix (ECM) proteins secreted by the invading extravillous trophoblasts. Integrins act as adhesion receptors and mediate both cell-ECM and cell-cell interactions. However, the correlation between integrin expression and trophoblast invasion under hypoxia is unclear. Here, we analyzed the expression of integrins in HTR-8/SVneo trophoblast cells exposed to hypoxic conditions in order to demonstrate an association between invasion activity and integrin expression in trophoblasts. Trophoblasts were examined by microarray analysis, RT-PCR, western blotting, and zymography after 1% hypoxic treatment, and cell invasion was estimated. The dynamic expression of integrins and human matrix metalloproteinases (MMPs) was observed under hypoxic conditions. The invasiveness of trophoblasts cultured under 1% hypoxic conditions was significantly greater than that of trophoblasts cultured under normoxic conditions through alterations in MMP-2 and -9 (P < 0.05). Notably, integrin α4 expression during early hypoxia was negatively regulated by hypoxia-inducible factor-1alpha (HIF-1alpha) expression in trophoblasts. The downregulation of integrin α4 expression by siRNA treatment controlled trophoblast invasion activity (P < 0.05). Taken together, we suggest that dynamic changes in integrins, including those in integrin α4 expression by hypoxia, play a regulatory role in trophoblast invasion. These findings expand our understanding of the potential roles of integrin α4 in implantation.

729: Altered DNA methylation of MMP 9, MMP 14, TIMP 3 and TIMP 4 associated with pregnancy

Matrix metalloproteinases (MMPs) degrade extracellular matrix; tissue inhibitors for MMPs (TIMPs) regulate this protease activity. Maternal leukocytes at the maternal-fetal interface express MMPs/TIMPs, controlling trophoblast invasion and angiogenesis. Altered expression of MMP 2, 9, 14, and TIMPs 1-4 have been associated with establishment of normal pregnancy and adverse pregnancy outcomes. We sought to characterize differential methylation patterns in pregnancy.

IFPA Award in Placentology Lecture: Molecular regulation of human trophoblast invasion

Invasion of extravillous trophoblast cell types into maternal uterine tissues is essential for successful human placental development and progression of pregnancy. Whereas endovascular trophoblasts migrate into the maternal spiral arteries, interstitial trophoblasts invade the decidual stroma, colonize the vessels from outside and communicate with diverse uterine cell types such as decidual stromal cells, macrophages and uterine NK cells. For example, interstitial trophoblasts expressing polymorphic human leukocyte antigen-C interact with uterine NK cells through binding to their killer immunoglobulin-like receptors which likely plays a role in trophoblast invasion and reproductive success of pregnancy. Both extravillous trophoblast subtypes are critically involved in the vascular transformation of the spiral arteries into dilated conduits ensuring appropriate blood flow into the intervillous space. Failures in this remodeling process are thought to be associated with severe forms of fetal growth restriction, preeclampsia and other pregnancy complications warranting studies on the molecular regulation of extravillous trophoblast differentiation. Moreover, interstitial trophoblast-derived hormones may regulate diverse biological functions in the decidua. In particular, human chorionic gonadotrophin has been shown to promote angiogenesis and to suppress apoptosis of endometrial stromal cells. In return, decidual cells produce a plethora of soluble factors controlling trophoblast invasion in a time- and distance-dependent manner. However, the underlying mechanisms have not been fully elucidated. Here, we will summarize autocrine as well as paracrine factors regulating invasion of extravillous trophoblasts and discuss critical signaling cascades involved. In addition, we will focus on key regulatory transcription factors controlling cell column proliferation and differentiation of the human extravillous trophoblast.

Inhibition of histone deacetylases in human endometrial stromal cells promotes extracellular matrix remodelling and inhibits embryo invasion

Trophoblast invasion into the maternal decidua requires the action of metalloproteinases (MMPs) to degrade extracellular matrix (ECM) proteins. In turn, decidual cells express tissue inhibitors of MMPs (TIMPs) that restrain trophoblast invasion. Gene expression is post-transcriptionally regulated by histone deacetylases (HDACs) that unpacks condensed chromatin activating gene expression. The aim of this study was to analyse the effect of histone acetylation of human endometrial stromal cells (hESCs) on the expression of TIMPS hESCs were treated with HDAC inhibitor Trichostatin A (TSA) and the thophoblast invassion was assessed. hESCs from endometrial biopsies (n = 3) were isolated and treated with TSA or vehicle for 48hrs. Quantitative PCR for MMP2, MMP9, TIMP1, TIMP3 and uPA and zymograms for MMP2 and MMP9 activity were investigated. TSA pretreated hESCs for 48 h. vs control were used for wound healing and trophoblast invasion assays. For all studies, at least 3 different experiments were performed. Statistical analyses: t-Student. Inhibition of HDAC with TSA increases the mRNA expression of TIMP-1 and TIMP-3 (13- and 2-fold, respectively) while decreases MMP2 (14-), MMP9 (2.5-) and uPA (25-). Gelatine zymograms show a decrease in total MMP2 but also in the active form of MMP2 suggesting that TSA alters the expression of ECM components and its modulators. hESC TSA pretreated cells are 65% less motile and 50% less invasive than control cells. This phenotype correlates with the molecular change in the ECM described. Moreover, the potential invasion of mouse embryos in TSA treated hESCs is severely reduced compared to control (50% less) Our results demonstrate that histone acetylation reduces MMPs and increase their inhibitors in hESCs disrupting the balance of ECM modulators provoking a restrain of trophoblast invasion. These findings are important as an epigenetic mechanism that can be used to control trophoblast invasion

Trophoblast invasion and spiral artery transformation in placenta accreta

IntroductionPlacenta accreta is an increasingly prevalent cause of maternal morbidity/mortality. Decidua is, at least focally, defective and abnormal uterine invasion by extravillous trophoblast (EVT) has been proposed.AimExamine EVT invasion and...

The effects of human chorionic gonadotrophin, progesterone and oestradiol on trophoblast function

Remodelling of the uterine vasculature during the first trimester of human pregnancy requires invasion of trophoblast from the placenta into decidual spiral arterioles. The pregnancy-associated hormones human chorionic gonadotropin (hCG), progesterone (P 4) and oestradiol (E 2) are present at high concentrations at the maternal–fetal interface during the remodelling period and thus may contribute to the regulation of trophoblast movement. This study examined the effects of these hormones on trophoblast functions. HTR8/SVneo cells were treated with hCG (5–100 mIU/mL), P 4 (20 nM–20 μM) or E 2 (0.07–734 nM). hCG significantly stimulated migration and MMP-9 activity but did not affect cell numbers. P 4 significantly inhibited migration, MMP-2 and -9 activity and reduced cell numbers. E 2 had no effect on migration, MMP activity or cell numbers. We conclude that hCG and P 4, but not E 2, play direct roles in controlling trophoblast invasion, acting as positive and negative stimuli respectively to regulate trophoblast movement during vascular remodelling in early pregnancy.

Progesterone-induced blocking factor (PIBF) and trophoblast invasiveness

Controlled trophoblast invasion is a key process during human placentation and a prerequisite for successful pregnancy. Progesterone is one of the factors to regulate trophoblast invasiveness. Progesterone-induced blocking factor (PIBF) is a progesterone-induced molecule expressed by the trophoblast, and also by tumors. The distribution of PIBF within the first-trimester decidua coincides with sites of trophoblast invasion. Another molecule that has been implicated in the control of trophoblast invasiveness is placental leptin. Leptin inhibits the secretion of progesterone by cytotrophoblast. The aim of this work was to investigate the possible interaction of PIBF and leptins in regulating trophoblast invasion. Paraffin-embedded sections from normal first-trimester placentae, partial moles, complete moles, and choriocarcinomas were reacted with PIBF, leptin, and leptin receptor specific antibodies. PIBF-deficient trophoblast cells were generated using siRNA and leptin receptor was detected on Western blot analysis. The lysates of PIBF-treated cells were used for detecting leptin expression in a protein array. PIBF was expressed in both normal first-trimester villous trophoblast and in partial mole. Compared with this, PIBF expression was markedly decreased in complete mole and absent in choriocarcinoma. Neither leptinR nor leptin were detected in partial mole, whereas both of these molecules were present in complete mole and choriocarcinoma. Leptin receptor expression was upregulated in PIBF-deficient cells, while leptin expression was decreased in PIBF-treated cells. These data suggest that PIBF affects the expression of leptin and its receptor, and that PIBF expression is inversely related to trophoblast invasiveness.

Gimme shelter: the immune system during pregnancy

Antigen-presenting molecules vary between individuals of the same species, making it more difficult for pathogens to evade immune recognition and spread through the whole population. As a result of this genetic diversity, transplants between individuals are recognized as foreign and are rejected. This alloreactivity turns placental viviparity into a major immunological challenge. The maternal immune system has to balance the opposing needs of maintaining robust immune reactivity to protect both mother and fetus from invading pathogens, while at the same time tolerating highly immunogenic paternal alloantigens in order to sustain fetal integrity. Regulatory T cells are responsible for the establishment of tolerance by modulating the immune response, and uterine natural killer cells direct placentation by controlling trophoblast invasion. A variety of other cell types, including decidual stromal cells, dendritic cells, and immunomodulatory multipotent mesenchymal stromal cells, are found at the fetal-maternal interface. These cells conspire to establish a suitable environment for fetal development without compromising systemic immunity. Defects in any of these components can lead to gestational failure despite successful fertilization.

Decidual HtrA3 negatively regulates trophoblast invasion during human placentation

BACKGROUND Controlled trophoblast invasion into the maternal decidua (interstitial invasion) is important for placental development. Factors secreted by the maternal decidual cells and the extravillous trophoblast can influence trophoblast invasion and abnormalities in the invasion process may lead to pregnancy complications. Serine protease HtrA3 is highly expressed in the decidual cells in the late secretory phase of the menstrual cycle and throughout pregnancy, and in most trophoblast cell types, apart from the invading interstitial trophoblast during the first trimester. HtrA3 and its family members are down-regulated in a number of cancers and are proposed as tumour suppressors. The current study aimed to investigate whether HtrA3 is secreted by decidual cells, and whether inhibiting such secretion alters trophoblast invasion. METHODS AND RESULTS Human endometrial stromal cells (HESCs) were decidualized with estradiol, medroxyprogesterone acetate and cyclic adenosine monophosphate. Real-time RT-PCR, western blotting and immunocytochemistry confirmed that HtrA3 mRNA and protein expression increased during decidualization. HtrA3 was also detected in the conditioned media (CM) of the decidualized HESCs, confirming its secretion. For functional studies, a protease-inactive mutant form of HtrA3 which was previously confirmed to be a dominant-negative inhibitor was produced using wheat germ cell-free technology. CM from decidualized HESCs significantly suppressed invasion of trophoblast HTR-8 cells (P < 0.01), whereas inhibition of HtrA3 in this CM by exogenous HtrA3 mutant resulted in increased trophoblast HTR-8 cell invasion (P < 0.001). CONCLUSIONS These results strongly support the hypothesis that decidual HtrA3 negatively regulates trophoblast invasion.

Immunoregulation by Cytolytic Pathways, Mucins and Progesterone at the Maternal-Fetal Interface

The maternal-fetal interface of pregnant mammals is characterized by a sensitive balance between hormones, cytokines, humoral factors and cellular interactions. Progesterone activity leads to the transformation of endometrial cells into the decidual phenotype and ensures the integrity of the maternal-fetal interface during trophoblast invasion and placenta maturation. Communication between the genomic and non-genomic progesterone-regulated signaling pathways could be of critical importance for the establishment of a correct endocrine-immune interaction in the human endometrium during the establishment and maintenance of pregnancy. Cytolytic cells (NK and T lymphocytes) infiltrating the decidua of pregnancy are heavily equipped with cytolytic molecules perofrin and granulysin. These molecules have very important role(s) in the maternal tolerance of fetoplacental unit, control of trophoblast invasion, defense against infective agents and malignancies, as well as immunomodulatory functions. Mucins MUC- 1 and TAG-72 are important features of secretory phase decidual reaction, while their dissapearance from the surface of the epithelial cells enables apposition, adhesion and infiltration of high quality blastocysts at the precise area at the time of the implantation. Muc-1 and TAG-72 induce antiinflammatory orientation of the decidual antigen presenting cells.

Effect of tumour necrosis factor-α in combination with interferon-γ on first trimester extravillous trophoblast invasion

Successful pregnancy is dependent upon invasion of the uterine tissues by extravillous trophoblast cells (EVT). The mechanisms that control trophoblast invasion are unclear, but several cytokines and growth factors appear to be involved. We have previously demonstrated that IFN-γ inhibits EVT invasion via a mechanism partially dependent on an increase in EVT apoptosis and decreased secretion of matrix metalloproteinase (MMP)-2. In the current study we show that TNF-α, both alone and in combination with IFN-γ, inhibits EVT invasion via a mechanism associated with increased trophoblast apoptosis, decreased trophoblast proliferation and/or altered production of active proteases. TNF-α and its receptors, TNF-αRI and TNF-αRII, were immunolocalised in the placental bed. Uterine natural killer (uNK) cells, EVT and villous cytotrophoblast were shown to all produce TNF-α, and TNF-α receptors were primarily immunolocalised to EVT in the placental bed. TNF-α increased EVT apoptosis, decreased villous cytotrophoblast proliferation and increased expression of pro-MMP-9 (but not active MMP-9), urokinase plasminogen activator (uPA) and plasminogen activator inhibitor (PAI)-1 by EVT. The combination of TNF-α and IFN-γ inhibited EVT via a mechanism associated with increased EVT apoptosis, reduced proliferation, reduced pro-MMP-2 secretion and increased secretion of uPA. TNF-α is one of several decidua-derived factors with the capacity to inhibit EVT invasion. The mode of activity of TNF-α was modified by the presence of IFN-γ, suggesting that the local cytokine milieu may be critical in determining spatial and/or temporal changes in EVT invasion.

ORIGINAL ARTICLE: Role of Regulatory and Angiogenic Cytokines in Invasion of Trophoblastic Cells

Citation Dubinsky V, Poehlmann TG, Suman P, Gentile T, Markert UR, Gutierrez G. Role of regulatory and angiogenic cytokines in invasion of trophoblastic cells. Am J Reprod Immunol 2010; 63: 193–199Problem Trophoblast invasion is a temporally and locally restricted process, which regulates implantation and oxygen arrival to the embryo through the dialog with spiral artery endothelium. Trophoblast factors with angiogenic potential are activated by hypoxia. Their capacities to induce proliferation, migration, and invasion of trophoblastic cells have been investigated.Method of study The expression of interleukin (IL)‐6, CD126, CD130, vascular endothelial growth factor (VEGF), and hypoxia inducible factor‐1α (HIF‐1α) has been silenced in JEG‐3 choriocarcinoma cells by using siRNA. Silencing efficacy has been assessed by ELISA, PCR or Western blotting. Proliferation has been measured by flow cytometry, migration by a transwell assay, and invasion by a Matrigel assay.Results Proliferation was significantly reduced by silencing of CD126 or CD130, migration by silencing of IL‐6, VEGF, or HIF‐1α, and invasion by silencing of IL‐6 and HIF‐1α.Conclusion The expression of IL‐6, VEGF, and HIF‐1α in trophoblastic cells is involved in the control of trophoblast invasion and migration.

304. DECIDUAL HtrA3 NEGATIVELY REGULATES TROPHOBLAST INVASION

Controlled trophoblast invasion cell into the maternal decidua (interstitial invasion) is important for placental development. Abnormalities in the invasion process may lead to pregnancy complications. Decidua secrets many factors to control trophoblast invasion. Serine protease HtrA3 is highly expressed in the decidual cells in the late secretory phase of the menstrual cycle and throughout pregnancy. It is highly expressed in first trimester in most trophoblast cell types, but not in the invading interstitial trophoblast. HtrA3 and its family members are down-regulated in a number of cancers and are proposed as tumor suppressors. We hypothesized that HtrA3 is an inhibitor of trophoblast invasion. The current study aimed to investigate whether HtrA3 secreted by decidual cells regulates trophoblast invasion. Human endometrial stromal cells (HESC) were decidualised with estradial, medroxyprogesterone acetate and cyclic AMP. Real-time RT-PCR, western blotting and immunocytochemistry demonstrated that decidualisation increased HtrA3 mRNA and protein expression. HtrA3 was also detected by western blotting in the conditioned media (CM) of decidualised HESC (96h), confirming its secretory nature. For functional studies, wild type and protease inactive mutant HtrA3 were produced using wheat germ cell-free technology. The mutant has negligible protease activity and significantly inhibited the wild type protease activity, supporting its dominant-negative inhibition and utility as a specific inhibitor of the wild type protein. CM of decidualised HESC suppressed invasion of trophoblast HTR-8 cells, whereas inhibition of HtrA3 in the decidual HESC CM by exogeneous addition of HtrA3 mutant increased trophoblast HTR-8 cell invasion. These results strongly support our hypothesis that decidual HtrA3 negatively regulates trophobalst invasion.

Critical growth factors and signalling pathways controlling human trophoblast invasion

Invasion of placental trophoblasts into uterine tissue and vessels is an essential process of human pregnancy and fetal development. Due to their remarkable plasticity invasive trophoblasts fulfil numerous functions, i.e. anchorage of the placenta, secretion of hormones, modulation of decidual angiogenesis/lymphangiogenesis and remodelling of maternal spiral arteries. The latter is required to increase blood flow to the placenta, thereby ensuring appropriate transfer of nutrients and oxygen to the developing fetus. Since failures in vascular changes of the placental bed are associated with pregnancy diseases such as preeclampsia or intrauterine growth restriction, basic research in this particular field focuses on molecular mechanisms controlling trophoblast invasion under physiological and pathological conditions. Throughout the years, an increasing number of growth factors, cytokines and angiogenic molecules controlling trophoblast motility have been identified. These factors are secreted from numerous cells such as trophoblast, maternal epithelial and stromal cells, as well as uterine NK cells and macrophages, suggesting that a complex network of cell types, mediators and signalling pathways regulates trophoblast invasiveness. Whereas essential features of the invasive trophoblast such as expression of critical proteases and adhesion molecules have been well characterised, the interplay between different cell types and growth factors and the cross-talk between distinct signalling cascades remain largely elusive. Similarly, key-regulatory transcription factors committing and differentiating invasive trophoblasts are mostly unknown. This review will summarise our current understanding of growth factors and signal transduction pathways regulating human trophoblast invasion/migration, as well as give insights into novel mechanisms involved in the particular differentiation process.