Trophoblast invasion in pre-eclampsia

It is generally accepted that insufficient invasion of trophoblast cells into the myometrial portions of the spiral arteries is thought to play a crucial role in the development of preeclampsia. As a consequence, uteroplacental vessels fail to undergo adaptive changes which are imperative to provide a sufficient blood supply to the placenta. Consecutive placental hypoxia is supposed to cause secretion/shedding of still unidentified placental metabolites resulting in different forms of pregnancy-induced hypertension. This review presents published data concerning the causes of insufficient trophoblast invasion in preeclampsia. Expression of HLA-G by extravillous trophoblast cells seems to be altered, resulting in activation of the maternal immune system. The pattern of integrin expression as well as the secretion of proteases is reported to be disturbed, which could lead to a reduced invasive potential of the trophoblast cells. Recent data indicate a pathophysiological role of NK-cells and macrophages in the altered trophoblast invasion. Also angiotensinogen Thr235 polymorphism seems to alter early physiologic changes in spiral arteries. In summary, preeclampsia seems to be induced by a multifactorial disturbance of trophoblast invasiveness which is characterized by reduced invasiveness of the trophoblast cells themselves and by an activated maternal immune response blocking the invasion by the semiallogenic trophoblast.     

Placental oxidative stress: from miscarriage to preeclampsia

OBJECTIVE: To review the role of oxidative stress in two common placental-related disorders of pregnancy, miscarriage and preeclampsia. METHODS: Review of published literature. RESULTS: Miscarriage and preeclampsia manifest at contrasting stages of pregnancy, yet both have their roots in deficient trophoblast invasion during early gestation. Early after implantation, endovascular trophoblast cells migrate down the lumens of spiral arteries, and are associated with their physiological conversion into flaccid conduits. Initially these cells occlude the arteries, limiting maternal blood flow into the placenta. The embryo therefore develops in a low oxygen environment, protecting differentiating cells from damaging free radicals. Once embryogenesis is complete, the maternal intervillous circulation becomes fully established, and intraplacental oxygen concentration rises threefold. Onset of the circulation is normally a progressive periphery-center phenomenon, and high levels of oxidative stress in the periphery may induce formation of the chorion laeve. If trophoblast invasion is severely impaired, plugging of the spiral arteries is incomplete, and onset of the maternal intervillous circulation is premature and widespread throughout the placenta. Syncytiotrophoblastic oxidative damage is extensive, and likely a major contributory factor to miscarriage. Between these two extremes will be found differing degrees of trophoblast invasion compatible with ongoing pregnancy but resulting in deficient conversion of the spiral arteries and an ischemia-reperfusion-type phenomenon. Placental perfusion will be impaired to a greater or lesser extent, generating commensurate placental oxidative stress that is a major contributory factor to preeclampsia. CONCLUSION: Miscarriage, missed miscarriage, and early- and late-onset preeclampsia represent a spectrum of disorders secondary to deficient trophoblast invasion.     

Role of nuclear receptors and their ligands in human trophoblast invasion

Human implantation involves a major invasion of the uterine wall and complete remodelling of uterine arteries by extravillous cytotrophoblasts (EVCT). Abnormality in these early steps of placental development leads to poor placentation, fetal growth defects and is often associated with preeclampsia, a major and frequent complication of human pregnancy. To study the mechanisms that control trophoblast invasion during early placental development and provide new insight in the understanding of preeclampsia, we have developed in vitro models of human invasive trophoblasts. We have shown that activation of the ligand-activated nuclear receptor PPARgamma with synthetic (rosiglitazone) or natural (15deoxyPGJ(2)) agonists inhibits the trophoblastic invasion process. Analysis of PPARgamma-target genes revealed that placental growth hormone and the protease PAPP-A might be involved in the PPARgamma-mediated effect in an autocrine manner. We next investigated PPARgamma ligands at the materno-fetal interface and have shown that oxidized LDLs are present in EVCT in situ and decrease trophoblast invasion in vitro. Analysis of oxidized LDLs revealed that they contain potent PPARgamma agonists such as eicosanoids and also high levels of oxysterols, which are specific ligands for the liver X receptor (LXR). The isoform beta of LXR was found in EVCT in situ, and activation of LXRbeta with synthetic or natural ligands inhibits trophoblast invasion in vitro. Together, our data underscore a major role for PPARgamma and LXRbeta in the control of human trophoblast invasion and suggest that excess ligands such as oxidized LDLs at the implantation site might contribute to the development of preeclampsia.     

Implantationsst?rungen, Pr?eklampsie und intrauterine Wachstumsrestriktion

Preeclampsia and intrauterine growth restriction (IUGR) are major pregnancy pathologies and the leading causes of maternal and perinatal mortality and morbidity. Interestingly the etiologies of both syndromes are still unclear which is why a large number of hypotheses have been developed. The joint occurrence of both syndromes in a single pregnancy has deleterious effects on both mother and child. Studies dealing with such severe cases of preeclampsia with associated IUGR have led to the development of hypotheses attempting to explain all clinical and morphological alterations in a single hypothesis. This in turn has resulted in the general misconception that a failure in invasion of the placental trophoblast is directly linked with the etiology of preeclampsia. However, recent progress in the identification of new biomarkers to predict preeclampsia has changed views on the etiology of preeclampsia. It has become clear that a failure in trophoblast invasion is directly linked to IUGR while a defect of the villous trophoblast precedes preeclampsia.     

Review: hCG, preeclampsia and regulatory T cells

Human chorionic gonadotropin (hCG) is crucial for successful pregnancy. Its many functions include angiogenesis and immune regulation. Despite years of research, the etiology of preeclampsia remains unknown. Marked by insufficient trophoblast invasion and poor spiral artery remodeling, preeclampsia has also been linked to immune dysregulation. Here we discuss the roles of hCG in the context of endovascular cross-talk between trophoblasts and endothelial cells and immune tolerance. We propose that functional and glycosylation modifications of hCG may contribute to the pathogenesis of preeclampsia.     

Down-regulated long non-coding RNA-ATB in preeclampsia and its effect on suppressing migration,proliferation, and tube formation of trophoblast cells

Preeclampsia is a pregnancy-specific syndrome and is one of the main causes of maternal, fetal, and neonatal morbidity and mortality. Inadequate trophoblast invasion and failure of uterine spiral artery remodeling exert a major role in the development of preeclampsia, especially the early-onset one. LncRNA-ATB is verified to be aberrantly expressed in many cancers and promote the invasion-metastasis and proliferation cascades. But little is known of lncRNA-ATB's role in preeclampsia. The aim of current study is to identify the changes of lncRNA-ATB in preeclampsia and its effects on trophoblast. The lncRNA-ATB levels were decreased in placental samples collected from preeclampsia women (n = 51) compared to those of healthy pregnant women (n = 40) by qRT-PCR analysis. Besides, it is demonstrated that lncRNA-ATB was intense stained in the trophoblast of the placenta by performing in-situ hybridization. By designing RNA interference species to suppress lncRNA-ATB and specific plasmids designed to overexpress lncRNA-ATB, we identify the role of lncRNA-ATB on the functions of trophoblast cell-line, HTR-8/SVneo. Inhibition of endogenous lncRNA-ATB decreased migration, proliferation, tube-formation of HTR-8/SVneo cells. In addition, overexpression of lncRNA-ATB promoted migration, proliferation, and tube-formation of HTR-8/SVneo cells. Therefore, lncRNA-ATB might be involved in the pathogenesis of preeclampsia by regulating the process of trophoblast invasion and endovascular formation.     

Altered protease expression by periarterial trophoblast cells in severe early-onset preeclampsia with IUGR

Adaptation of uteroplacental arteries in patients with early-onset preeclampsia combined with IUGR is compromised due to insufficient invasion of extravillous trophoblast cells (EVT) into the spiral artery wall. The underlying molecular mechanisms are widely unknown. We investigated expression and possible mechanisms of regulation of different matrix-metalloproteases (MMPs) by EVT in placental bed biopsies from patients with early onset preeclampsia combined with IUGR and healthy pregnant women. Expression of MMP-3 and MMP-7 by EVT was markedly reduced in preeclamptic patients, especially close to spiral arteries. In contrast to healthy pregnancies these cells strongly expressed the receptor for leukemia inhibitory factor (LIF). LIF is known to suppress MMP-expression and is produced by uterine natural killer (uNK) cells which we found to be present in higher concentrations in the placental bed of preeclamptic patients, and accumulating aside the spiral arteries. We speculate that in preeclampsia a maternal immune cell network accumulating and interfering in the placental bed leads to an altered cytokine environment, resulting in disturbed trophoblast cell function such as impaired MMP expression and reduced invasiveness.     

CXCR2 is decreased in preeclamptic placentas and promotes human trophoblast invasion through the Akt signaling pathway

IntroductionCXCR2, the receptor of the CXC chemokines, plays a critical role in cell migration and invasion in many types of cancer. It is unclear what impact CXCR2 may have on Preeclampsia (PE), a pregnancy-specific disease, which is related to insufficient trophoblast invasion. The aim of this study was to investigate the expression pattern of CXCR2 in the placentas of healthy and PE pregnancies, and to investigate the molecular mechanism of CXCR2 involvement in the development of PE.MethodsCXCR2 expression levels in newly delivered placentas from 38 pregnant women with PE and 21 healthy pregnant women were detected using quantitative real-time PCR, immunohistochemistry and Western blot assays. The effect of CXCR2 on trophoblast invasion and the underlying mechanisms were examined in two trophoblast cell lines (HTR-8/SVneo and TEV-1 cells).ResultsCXCR2 mRNA and protein expression levels were significantly decreased in preeclamptic placentas than normal control. The invasive abilities of the two trophoblast cell lines were significantly inhibited when CXCR2 was silenced, but that CXCR2 overexpression promoted trophoblast cells invasion. In addition, silencing CXCR2 reduced the expression of matrix metalloproteinase 2 and 9 (MMP2 and MMP9) and phosphorylated Akt (p-Akt). Furthermore, an Akt inhibitor suppressed the expression of MMP-2 and MMP-9.DiscussionOur results suggest that the decreased CXCR2 may contribute to the development of preeclampsia through impairing trophoblast invasion by down-regulating MMP-2 and MMP-9 via the Akt signaling pathway.     

Wnt5a inhibited human trophoblast cell line HTR8/SVneo invasion: implications for early placentation and preeclampsia

Objective: Wnt5a and Wnt signaling play potential roles in human placental and fetal development. The objective of this study is to explore the role of Wnt5a in the invasion of the human trophoblast cell line HTR8/SVneo and the probable mechanism of early placentation and preeclampsia in which Wnt5a is involved.

Methods: Human first trimester villous tissues from normal pregnancies and third trimester placentas from pregnancies with or without preeclampsia (PE) were used in the detection of the expression and subcellular location of Wnt5a. The human trophoblast cell line HTR8/SVneo was treated with 0–400?ng/ml recombinant Wnt5a to investigate the role of Wnt5a in human trophoblast invasion.

Results: Human first trimester villous is accompanied by the decreased expression of Wnt5a compared with term placenta. Upregulated Wnt5a was detected in PE placenta compared with the normal control. Wnt5a inhibited the migration and invasion of HTR8/SVneo cells with decreased integrin β1, α5 and N-cadherin. Moreover, Wnt5a downregulated β-catenin in HTR8/SVneo cells.

Conclusions: These findings strongly suggest that Wnt5a inhibits the invasion of HTR8/SVneo cells. Decreased Wnt5a facilitates early placentation, whereas increased Wnt5a contributes to the pathogenesis of PE with insufficient trophoblast invasion. Aberrant Wnt5a may function by impairing Wnt non-canonical/β-catenin signaling pathway in trophoblasts.     

母体蜕膜微环境与滋养细胞浸润

在正常妊娠过程中,胎盘滋养细胞具有类似肿瘤的浸润能力,但与肿瘤细胞不同的是,滋养细胞对母体子宫蜕膜的浸润受到机体的严格调控,是有节制的正常生理行为.滋养细胞侵入过度可以导致绒毛膜癌等滋养细胞疾病的发生,浸润不足则可造成流产、子痫前期等妊娠期疾病.目前,滋养细胞有节制浸润母体的机制尚不明确,研究表明母体蜕膜微环境对滋养细胞的浸润起着重要的调控作用,对其进行深入研究有助于理解病理性妊娠的发生、发展过程.     

Regulation of epithelial-mesenchymal transition by homeobox gene DLX4 in JEG-3 trophoblast cells: a role in preeclampsia

The pathogenesis of preeclampsia is unclear but is thought to be related to shallow trophoblast invasion. An invasive phenotype is acquired by trophoblasts through the process of epithelial-mesenchymal transition (EMT). We proposed that EMT in trophoblasts is deregulated in preeclampsia. The homeobox gene DLX4 plays an important role in epithelial-mesenchymal interactions during embryonic and placental development. To elucidate the role of DLX4 in trophoblast EMT and preeclampsia, we investigated the expression of DLX4 in preeclampsia-affected placentas and the effect of DLX4 on EMT in trophoblast-derived JEG-3 cells. DLX4 expression was downregulated in preeclampsia-affected placentas and hypoxic JEG-3 cells. Knockdown of DLX4 by RNA interference (RNAi) inhibited the motility and invasion ability of JEG-3 cells, decreased the expression of E-cadherin, and upregulated the expression of the E-cadherin repressor Snail. Our findings suggest that decreased expression of DLX4 leads to the pathogenesis of preeclampsia by inhibiting EMT in trophoblasts and provides new insight into the pathophysiological mechanism of preeclampsia.     

Why hypertension is good new and preeclampsia bad news-demonstrating the failure of prevention

Hypertensive disorders in pregnancy continue to be an intriguing and potentially lethal complication in humans and some other primates. In a simplistic way the current hypothesis is that the genesis of preeclampsia starts at 12 to 14 wk gestation with failure of trophoblast invasion in the spiral arteries, resulting in some degree of hypoxemia in the placenta. The hypoperfused placental tissue starts to secrete variable amounts of angiogenic and antiangiogenic factors which eventually cause endothelial damage all over the pregnant women’s body with one of the many signs of preeclampsia as the clinical endpoint. For some incomprehensible reason a major interest has existed for decades concerning the early prediction of preeclampsia, most commonly tested using uterine artery Doppler (the earlier the better) and various serum markers, alone or in combination. Any new model for detection has been welcomed enthusiastically, although nothing has changed in the outcome of women presenting with preeclampsia.     

Smad4在早发型子痫前期胎盘组织中的表达及意义

Objective?To investigate the expression of Smad4 in placental tissue of early onset preeclampsia and its possible role. Method?Smad4 expression was detected by RT-PCR, Western blot and immunohistochemistry in placental tissues of 30 cases of early onset preeclampsia and 30 healthy parturients. Transwell and scratch assay were used to detect the invasion and migration of trophoblast cell line HTR-8/SVneo cells. Result?Smad4 mRNA and protein levels in placental tissues of early onset preeclampsia were significantly increased (P<0.01); Compared with the si-Smad4 NC group, the invasion and mobility of HTR-8/SVneo cells were significantly increased after Smad4 silencing, and the difference was statistically significant (P<0.01). Conclusion?Smad4 expression is significantly increased in placental tissue of early onset preeclampsia, which may be involved in the occurrence and development of preeclampsia by affecting the biological function of trophoblast cells.     

Maternal autoantibodies from preeclamptic patients activate angiotensin receptors on human trophoblast cells

OBJECTIVES: Recent evidence indicates that preeclampsia is associated with the presence of autoantibodies capable of activating the angiotensin II receptor, AT1. We sought to evaluate the role of AT1 agonistic autoantibodies (AT1-AA) in two major features of preeclampsia-increased plasminogen activator inhibitor-1 (PAI-1) production and shallow trophoblast invasion. METHODS: This study included 38 pregnant patients, 20 of whom had severe preeclampsia and 18 normotensive individuals. Immunoglobulin (Ig)G was purified from these individuals, and the presence of AT1-AA was determined based on its ability to stimulate an increase in the contraction rate of cultured rat neonatal cardiac myocytes. Immortalized human trophoblasts were chosen to study PAI-1 production and secretion after treatment with IgG from normotensive and preeclamptic women. An in vitro Matrigel invasion assay was used to test the effect of AT1-AA on the invasive properties of human trophoblasts. Losartan and cyclosporin A were used to determine whether the AT1-AA-induced stimulation of PAI-1 secretion is through the AT1 receptor and the calcineurin-nuclear factor of activated t-cells (NFAT)-dependent pathway. RESULTS: The results show that IgG from 18 of 20 severely preeclamptic women stimulated increased cardiomyocyte contraction rates of 20-40 beats per minute. A significant stimulation of PAI-1 secretion from human trophoblasts was observed with IgG from the same 18 of 20 patients with severe preeclampsia. Of IgG obtained from 18 normotensive pregnant patients, only two showed a relatively low level of biologic activity in the cardiomyocyte contraction and PAI-1 secretion assays. Activation of AT1 receptors by AT1-AA was blocked by losartan (an AT1 receptor antagonist) and by a seven amino acid peptide corresponding to a sequence present on the second extracellular loop of the AT1 receptor. Activation of AT1 receptors by AT1-AA resulted in decreased trophoblast invasiveness as determined by the in vitro Matrigel invasion assay. Additional data indicate that AT1 receptor activation by AT1-AA is followed by the downstream activation of the calcium-dependent calcineurin-NFAT signaling pathway leading to increased PAI-1 gene expression. CONCLUSION: Our findings suggest that maternal autoantibody with the ability to activate AT1 receptors may account for two features of preeclampsia, increased PAI-1 production and shallow trophoblast invasion.     

miR-15b-AGO2 play a critical role in HTR8/SVneo invasion and in a model of angiogenesis defects related to inflammation

IntroductionmicroRNAs (miRs) have been shown to play critical roles in the regulation of trophoblast and endothelial cell functions, and one significant finding concerning the miR-15/16 family is that most members of this family are highly expressed in endothelial cells and contribute to functions, such as tube formation. The interaction between trophoblast and endothelial cell play an important role in normal placentation process. Therefore, the aims of this study were to investigate the expression of miR-15b in human placenta and to uncover the potential role of miR-15b as well as its target functional loop in trophoblast and endothelial cells. Whether inflammation could modulate the expression of miR-15b and its down-stream target was further investigated. Additionally, the potential link between miR-15b deregulation and preeclampsia was also explored in the placenta of patients diagnosed with preeclampsia.MethodsThe expression of miR-15b was studied in the placental tissue of a normal pregnancy using in situ hybridization, and the effects of miR-15b on proliferation, invasion, and angiogenesis were further explored in vitro using HTR-8/SVneo and HUVEC cell line models. A Lipopolysaccharides (LPS) treatment model in HTR-8/SVneo cell was utilized to explore the mechanism of how LPS treatment could lead to the activation of miR-15b expression. Western blot was used to detect the expression of proteins related to miR-15b mediated pathway in preeclamptic placentas.ResultsmiR-15b inhibits trophoblast cell invasion and endothelial cell tube formation by suppressing the expression of Argonaute 2 (AGO2), a major miRNA effecter protein. AGO2 is specifically localized to human placenta cytotrophoblast and endothelial cells, and it plays important roles in trophoblast cell invasion and endothelial cell tube formation. LPS treatment may lead to the overexpression of miR-15b and down-regulation of AGO2, which may be involved in shallow trophoblast cell invasion associated with the pathogenesis of preeclampsia. Chromatin immunoprecipitation assay indicates that increased occupancy of AGO2 to miR-15b promoter is responsible for the increased expression of miR-15b under the condition of LPS treatment. Furthermore, preeclamptic placentas have decreased expression of AGO2, but increased expression of miR-15b and TLR-4 compared to normal controls.DiscussionThis is the first report about the function of AGO2 in human trophoblast and endothelial cells in the placenta. The data indicates that the aberrant expression of miR-15b contributes to abnormal placentation by targeting AGO2 mRNA. This study provides insight into the potential role of the miR-15b and AGO2 functional loop in the placentation process.     

Quantitative analysis of trophoblast invasion in preeclampsia

BACKGROUND: The process of physiological conversion of spiral arteries is dependent on the invasion of the interstitium and spiral arteries of the uterine wall by invasive extravillous trophoblast thereby creating a high flow-low resistance vessel. Quantitative data on restriction of trophoblast invasion and failure of spiral artery transformation are limited in preeclampsia. AIM: This study morphometrically analyzes interstitial trophoblast cells and trophoblast cells embedded in the wall of the converted spiral arteries within the decidua and myometrium of normotensive and preeclamptic Black African pregnant women. METHODS: Placental bed biopsies were obtained from 25 normotensive pregnant women and 30 pregnant women complicated with hypertensive disorders. Biopsies were processed and immunostained for trophoblast cell identification, using anti-MNF 116 antibody. Image analysis of the trophoblast population within the decidua, myometrium and the spiral arteries was performed in the normotensive and in the severe proteinuric hypertensive groups. RESULTS: The mean field area percentage of trophoblast cells observed in the decidua of the normotensive women was 22.79 +/- 2.1% in comparison to 18.14 +/- 1.53% in the severe hypertensive group (p < 0.01). In the myometrium, the mean field area percentage of interstitial trophoblast cells (both mononuclear and multinuclear) was 10.04 +/- 2.1% of the field area of the normotensive group compared to 2.81 +/- 0.67% in the severe hypertensive group (p < 0.001). The mean field area percentage occupied by trophoblast cells in myometrial spiral arteries was 10.15% in the normotensive group compared to none in the severe hypertensive group. The latter group displayed medial disorganization, hyperplasia and endothelial vacuolation. CONCLUSION: This study demonstrates restricted invasion of the trophoblastic cells in preeclampsia. This inadequate invasion may influence vascular remodeling required for delivering adequate volumes of maternal blood to the placenta.     

Calprotectin plasma level is elevated in preeclampsia

BACKGROUND: Calprotectin is a protein found in myelomonocytic cells and plays a role in various physiological functions such as inflammatory processes and antiproliferation of cells, and in the neutrophil defense against bacterial infections. Preeclampsia is characterized by maternal endothelial dysfunction and by insufficient trophoblast invasion into the maternal endometrium (decidua). In addition, preeclampsia is associated with maternal leukocyte activation and we therefore wanted to investigate whether calprotectin levels in plasma from women with preeclampsia differed from the levels in normotensive pregnant and nonpregnant women. METHOD: Calprotectin measurements were included in a case-control study of 20 preeclamptic women matched with 20 normotensive pregnant women regarding age, pregnancy length, parity and body mass index (BMI). We also measured calprotectin in 12 nonpregnant women. Calprotectin plasma levels were analyzed using an enzyme-linked immunosorbent assay (ELISA). RESULTS: We discovered significantly elevated plasma calprotectin levels in preeclamptic patients compared to matched normotensive pregnancies: 768 (612-1016) microg/L vs. 445 (276-598) microg/L (medians, 25, 75 percentiles, respectively), p = 0.002. CONCLUSIONS: The elevated plasma calprotectin levels demonstrated in the preeclampsia group supports the notion that leukocytes are activated in preeclampsia. The elevated calprotectin level might constitute a part of the innate defense in myelomonocytic cells against microorganisms in pregnancy. We suggest further elucidation of a role for calprotectin in the development of pregnancy disorders such as preeclampsia.     

基质金属蛋白酶与子痫前期发病关系的研究

目的 探讨基质金属蛋白酶(MMP)2、9在子痫前期患者胎盘绒毛中的表达及其与子痫前期发病的关系.方法 采用免疫组化链霉亲和素-生物素-过氧化物酶复合物(SABC)法检测20例子痫前期患者(病例组)和20例正常孕妇(对照组)胎盘绒毛MMP-2、9的表达,实时荧光定量RT-PCR检测两组孕妇胎盘绒毛MMP-2、9 mRNA的表达水平.因提取后的mRNA部分降解,用于RT-PCR检测的胎盘绒毛病例组13份,对照组10份.采用2-△△Ct相对定量表示PCR结果.结果 对照组孕妇胎盘绒毛MMP-2、9的染色强度均高于病例组,两组比较,差异有统计学意义(P＜0.05);对照组胎盘绒毛MMP-2 mRNA的平均表达水平为7.6±2.8,病例组胎盘绒毛MMP-2 mRNA的平均表达水平为5.6±1.5,两组比较,差异有统计学意义(P＜0.05).对照组胎盘绒毛MMP-9 mRNA的平均表达水平为2.2±2.6,高于病例组的-0.9±2.0,两组比较,差异也有统计学意义(P＜0.05).对照组胎盘绒毛MMP-2的平均表达水平高于MMP-9,两者比较,差异有统计学意义(P＜0.05).结论 MMP-2、9表达降低导致的滋养细胞侵袭能力的下降,可能与子痫前期的发病相关.     

CDX1 restricts the invasion of HTR-8/SVneo trophoblast cells by inhibiting MMP-9 expression

Introduction

Pathogenesis of early-onset preeclampsia (PE) is generally recognized by impaired trophoblast invasion of the myometrial arteries, which results in placental insufficiency. Recently, we reported that CDX1 is hypermethylated in the human preeclampsia placenta. However, whether CDX1 participates in trophoblast invasion has not been clearly elucidated.

Methods

We investigated the function of CDX1 in the extravillous trophoblast cell line HTR-8/SVneo using stable transfection of CDX1. Using a CDX1 stable transfected cell line, we determined the cell invasion using a QCM ECMatrix 24-well kit. The cell viability was detected using an MTT (3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide) assay. Quantitative RT-PCR and western blotting analyses were performed to examine the changes in the expression of downstream target genes and proteins. To disrupt PI3K/AKT signaling, we used the PI3K inhibitor perifosine.

Results

Cell invasion assays demonstrated that CDX1 restricts trophoblast cell invasiveness. In contrast, quantification of cumulative cell numbers revealed that CDX1 did not affect cell proliferation. Western blotting analysis and quantitative real time PCR demonstrated that MMP-9 expression was reduced, whereas TIMP-1 expression was increased in CDX1-overexpressed cells. However, overexpression of CDX1 did not affect PI3K/AKT signaling in HTR-8/SVneo trophoblast cells. In contrast, CDX1 was regulated by the PI3K/AKT signaling pathway.

Conclusions

Altogether, we found that in trophoblast cells, CDX1 reduced invasion independently of the PI3K/AKT signaling pathway. Furthermore, CDX1 functions in concert with PI3K/AKT signaling to regulate trophoblast invasion. We concluded that CDX1 restricts the invasion of HTR-8/SVneo trophoblast cells by inhibiting MMP-9 expression independently of the PI3K/AKT pathway.