Low Molecular Mass Polypeptide-2 in Human Trophoblast: Over-Expression in Hydatidiform Moles and Possible Role in Trophoblast Cell Invasion

Embryo implantation involves invasion of placental extravillous trophoblast cell (EVTs) into the uterus. Hyperactive EVT invasion occurs in hydatidiform moles and choriocarcinomas. We have previously demonstrated that the 20S proteasome is involved in mouse embryo implantation and its action is mediated via regulating the expression and activities of matrix metalloproteinase (MMP)-2 and MMP-9 in the EVTs. Our objective was to investigate whether low molecular mass polypeptide-2 (LMP2), a beta subunit of the 20S proteasome, is involved in the regulation of human trophoblast invasion. Normal human placentas or placentas from hydatidiform mole patients were collected and the expression of LMP2 in different cell types including trophoblastic column (TC), cytotrophoblast cells (CTB) and syncytiotrophoblast (STB) under different pathological states were studied by immunohistochemical analysis. Furthermore, the effect of LMP2 or proteasome on cell invasion was measured by using RNAi and inhibitors in a Matrigel invasion assay system in HTR-8/SVneo cells, a human invasive extravillous trophoblast cell line. Changes in the invasion-related molecules including MMP-2 and MMP-9 were also examined by using real time PCR and gelatin zymography. We demonstrated that the expression of LMP2 in TC of partial hydatidiform mole and complete hydatidiform mole, is higher than that in TC of normal human placentas. Besides, LMP2 knockdown significantly attenuated IL-1β-induced cell invasion in vitro, a response readily induced by proteasome inhibitors. In summary, over-expression of the 20S proteasome β-subunit LMP2 in trophoblast cells of hydatidiform moles may contribute to its highly invasive phenotype.     

Preeclampsia associates with RECK-dependent decrease in human trophoblasts migration and invasion

IntroductionPreeclampsia is characterized by reduced invasion capacity of trophoblasts involving lower matrix metalloproteinase (MMP) activity. Cell invasion is reduced by reversion-inducing-cysteine-rich protein with Kazal motifs (RECK), a plasma membrane protein that inhibits MMP in several cell types. However, it is unknown whether this mechanism happens in the human placenta from preeclampsia. The hypothesis of this study sustains that RECK expression is increased leading to reduced trophoblasts invasion in preeclampsia.MethodsRECK expression in the human first trimester trophoblast cell line HTR8/SvNeo and in placentas from normal (n = 4) and preeclampsia (n = 4) pregnancies was evaluated by Western blot and immunofluorescence. MMP-dependent gelatin hydrolyzation was measured by in situ zymography and gelatinase assay in placental and cell extracts. RECK was overexpressed (plasmidial vector transfection) or partially reduced (shRNA) to evaluate its role in HTR8/SVneo cell migration and invasion.ResultsRECK was expressed in trophoblasts layer in human placentas. Preeclampsia resulted in higher placental RECK protein abundance, reduced MMP function, and higher level of fibronectin (a MMP substrate) compared with placentas from normal pregnancies. RECK is also expressed in HTR-8/SVneo cells. Reduced RECK expression resulted in higher MMP-dependent gelatin hydrolyzation, associated to higher migration and invasion of HTR8/SVneo cells. However, RECK overexpression associated with reduced hydrolyzation, cell migration and invasion.DiscussionRECK is overexpressed in human trophoblasts from preeclampsia and may be responsible of this disease-associated lower migration and invasion of this cell type.     

Conditioned Medium from Human Decidual Stromal Cells has a Concentration-dependent Effect on Trophoblast Cell Invasion

The regulation of trophoblast cell invasion is a crucial aspect of implantation and placental development. Evidence indicates that the uterine microenvironment exerts important influence over trophoblast cell invasion. However, the precise effect of decidual cells on trophoblast cell invasion remained unidentified. In the present study, a cell line representative of normal human trophoblast (B6Tert) was used to examine the effect of decidual stromal cell conditioned media (DSCM) on trophoblast cell invasion. In vitro assay showed the concentration-dependent effect of DSCM on B6Tert cell invasion. RT-PCR and gelatin zymography demonstrated that DSCM evidently produced an effect on the mRNA expression and proenzyme production of MMP-2 in a dose-dependent manner, but exerted no effect on mRNA expression and proenzyme production of MMP-9. The data indicates that the decidual microenvironment may exert the key control for trophoblast cell invasion mainly through influencing MMP-2 expression.     

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.     

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.     

The granulocyte colony-stimulating factor (G-CSF) upregulates metalloproteinase-2 and VEGF through PI3K/Akt and Erk1/2 activation in human trophoblast Swan 71 cells

IntroductionAlthough the expression of the granulocyte colony-stimulating factor (G-CSF) and its receptor (G-CSFR) in placental tissues suggests that the cytokine could play a role in placental development, the relevance of G-CSF:G-CSFR interaction in trophoblast cells remains to be studied. Thus, the possible functional role of G-CSF was examined in a human trophoblast cell line (Swan 71 cells).Methods and resultsThe expression of G-CSFR was detected by immunocytochemistry and Western blot assays. G-CSF treatment exerted neither a proliferative nor a protective effect on H₂O₂-mediated cell death in trophoblast cells. Gelatin zymography of supernatants collected from G-CSF-treated cells showed an increment of metalloproteinase-2 (MMP-2) activity. We also found higher MMP-2 and VEGF expression levels in conditioned medium from cells exposed to G-CSF. In addition, it was demonstrated that G-CSF induced the activation of PI3K/Akt and Erk1/2 pathways, which in turn activated NF-kB. By using selective pharmacological inhibitors, it was showed that these pathways are mediating the biological effects produced by G-CSF in Swan 71 cells.Discussion and conclusionWe have demonstrated for the first time that G-CSF increases MMP-2 activity and VEGF secretion in Swan 71 cells through activation of PI3K/Akt and Erk signaling pathways, both contributing to the translocation of NF-kB to the nucleus. These data suggest that G-CSF is involved in the regulation of trophoblast function, and should be considered as a locally produced cytokine probably contributing to embryo implantation and the development of a functional placenta.     

PTEN在子痫前期胎盘滋养细胞浸润不足中的作用及机制研究26

目的:检测子痫前期(PE)患者胎盘组织中PTEN表达,探讨PTEN对滋养细胞迁移功能的调控及其可能机制.方法:收集重度PE患者和正常孕妇的胎盘组织各20例,实时定量PCR和Western blot法检测胎盘组织中PTEN表达;将PTEN过表达质粒(pcDNA3.1-HA-PTEN)或特异性siRNA(siPTEN)瞬时转染至HTR-8/SVneo细胞,同时转染pcDNA3.1或siCTL作为对照.采用划痕实验评估细胞迁移能力,Western blot法检测p-Akt(Thr308)、p-Akt(Ser473)、Akt、MMP-2和MMP-9表达.结果:重度PE患者胎盘组织中PTEN mRNA和蛋白表达明显高于正常孕妇,差异均有统计学意义(P<0.01).与转染pcDNA3.1组比较,pcDNA3.1-HA-PTEN瞬时转染HTR-8/SVneo细胞48 h后,细胞迁移率明显降低[(26.42±6.68)%vs(52.92±6.71)%,P<0.01],p-Akt(Thr308)和p-Akt(Ser473)表达显著下调,Akt表达无明显改变,MMP-2和MMP-9蛋白表达下降;与转染siCTL组比较,siPTEN瞬时转染HTR-8/SVneo细胞48 h后,细胞迁移率则明显升高[(50.39±6.84)%vs(30.04±5.40)%,P<0.01],p-Akt(Thr308)和p-Akt(Ser473)的表达明显上调,Akt表达无明显改变,MMP-2和MMP-9蛋白表达升高.结论:重度PE患者胎盘组织中PTEN表达明显升高,PTEN可通过下调Akt活性降低MMP-2和MMP-9表达,抑制滋养细胞的迁移.提示PTEN在PE的发病中发挥了一定的作用.     

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.     

蜕膜基质细胞条件培养液对滋养细胞浸润功能的影响

目的:探讨蜕膜基质细胞条件培养液(DSCM)对滋养细胞浸润力的影响。方法:体外培养人早孕正常蜕膜基质细胞,收集DSCM处理早孕滋养细胞系(B6Tert)。应用浸润实验分析B6Tert细胞浸润力的改变,采用RT-PCR与明胶酶谱技术检测B6Tert细胞中基质金属蛋白酶(MMPs)的表达变化。结果:DSCM浓度较低时(占细胞培养液5%),可促进B6Tert细胞的浸润力与该细胞MMP-2mRNA及pro-MMP-2的表达;反之,高浓度的DSCM(20%)则抑制滋养细胞的浸润力与MMP-2的表达,差异有统计学意义(P<0.05)。DSCM不影响B6Tert细胞中MMP-9的表达。结论:早孕DSCM可能通过调节滋养细胞中MMP-2的表达影响滋养细胞的浸润能力。     

Downregulated N-acetylglucosaminyltransferase III is involved in attenuating trophoblast migration and invasion under hypoxia–reoxygenation condition

Objective: Many studies have confirmed that N-acetylglucosaminyltransferase III (GnT-III) is correlated with tumor invasion and metastasis. However, the expression of GnT-III and its role in normal pregnancy and preeclampsia (PE) has not been reached. So the primary objective of this study is to determine GnT-III expression in normal pregnancy and whether its expression is vulnerable to oxidative stress in the trophoblast cells.

Methods: Human first trimester villous tissues from normal pregnancies and third trimester placentas from pregnancies with or without preeclampsia (PE) were used for the detection of GnT-III expression. Human first trimester extravillous trophoblast cell line (HTR8/SVneo) exposed to hypoxia/reoxygenation (H/R) condition was employed as an oxidative stress model in vitro to investigate the expression of GnT-III.

Results: GnT-III was strongly expressed in cytotrophoblast (CTBs), syncytiotrophoblast (STBs) and the trophoblast columns (TCs) of human placental villi, and decidual cells in the maternal decidua. The expression of GnT-III was decreased in PE placentas compared with the normal control placentas. In addition, GnT-III was found to have decreased expression in H/R-exposed HTR8/SVneo cells, and the invasive and migratory abilities of HTR8/SVneo cells were attenuated, too.

Conclusions: These findings suggest that GnT-III is an important regulator at the maternal-fetal interface during early pregnancy. Excessive oxidative stress can decrease GnT-III expression in trophoblast and the decreased expression of GnT-III may be involved in the development of preeclampsia.     

Expression of inflammatory cytokines in placentas from pregnancies complicated with preeclampsia and HELLP syndrome

Abstract

Objective: To investigate the expression of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) in villous trophoblast, syncytial knots and decidua placentas from pregnancies complicated with preeclampsia (PE), Hemolysis, Elevated Liver enzymes and Low Platelet count (HELLP) syndrome and gestational age-matched controls.

Methods: Study group included 35 placentas from pregnancies complicated with PE and 35 placentas from pregnancies with HELLP syndrome. Control group included 35 placentas from idiopathic preterm labor. Placentas were matched according to the gestational age. Expression of TNF-α, IL-6 and IL-10 was determined by immunohistochemistry and semi-quantitative HSCORE method in villous trophoblast, syncytial knots and decidua. Non-parametric statistics were used for analyses.

Results: There was no difference in the expression of TNF-α, IL-6 and IL-10 in all the studied placental segments between PE, HELLP and gestational age-matched control group. TNF-α (F?=?32, 41, p?<?0.001), IL-6 (F?=?58, 53, p?<?0.001) and IL-10 (F?=?17, 62, p?<?0.001) expression was significantly different in different placental cell types, the highest expression of cytokines was in decidua.

Conclusion: There was no difference in cytokine expression in villous trophoblast, syncytial knots and decidua among the studied placental groups. The expression of cytokines was highest in decidua in all the studied placental groups.     

The tumor suppressor gastrokine-1 is expressed in placenta and contributes to the regulation of trophoblast migration

Introduction

Gastrokine-1 (GKN1) is a secreted auto-/paracrine protein, described to be expressed in the gastric mucosa. In gastric cancers GKN1 expression is commonly down-regulated. While current research focusses on the exploration of tumor-suppressive properties of GKN1 with regard to its potential clinical use in the treatment of gastroenterologic tumor disease, nothing is known about GKN1 expression and function in other organ systems. We investigated GKN1 expression in placental tissue and cells.

Materials and methods

GKN1 was localized using immunohistochemistry in first and third trimester placental tissue, hydatidiform moles and various gestational trophoblastic neoplasias. We determined the expression of GKN1 in immunomagnetic bead-separated term placental cells and in choriocarcinoma cell lines. The role of GKN1 for JEG-3 migration was studied using live cell imaging. E-cadherin, MMP-2 and -9, TIMP-1 and -2, as well as urokinase (uPA) expression levels were determined.

Results

GKN1 is expressed in healthy third trimester placentas. Its expression is specifically limited to the extravillous trophoblast (EVT). GKN1 expression is significantly reduced in choriocarcinoma cell lines and gestational trophoblastic neoplasias. GKN1 attenuates the migration of JEG-3 choriocarcinoma cells in vitro, possibly via AKT-mediated induction of E-cadherin. GKN1 treatment reduced MMP-9 expression in JEG-3.

Discussion

Besides its role in gastric physiology our results clearly indicate regulatory functions of GKN1 in the EVT at the feto-maternal interface during pregnancy. Based on our findings in the JEG-3 choriocarcinoma cell line, an auto-/paracrine role of GKN1 for EVT motility and villous anchorage at the basal plate is conceivable. Thus, the tumor suppressor GKN1 is expressed in placental EVT and might contribute to the regulation of EVT migration/invasion.     

Expression of EGF,EGFR, and proliferation in placentas from pregnancies complicated with preeclampsia

Objective: To investigate proliferation, EGF and EGFR expression of villous trophoblast (VTB), decidual cells (DC), and extravillous trophoblast (EVTB) in the placentas from pregnancies complicated with preeclampsia (PE) and to compare them with placentas from normal pregnancies. Methods: Twenty-nine PE placentas and 19 control placentas were studied for EGF and EGFR immunohistochemical expression (noted as week, moderate or strong). Proliferation was expressed as the proliferation index. The CK7 antibody was used to distinguish DC from EVTB. Results: DC and EVTB proliferation was significantly higher in PE placentas. EGFR and EGF expression showed no significant difference. Conclusion: Higher DC and EVTB proliferation in PE could contribute to PE development.     

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.     

Expression of Gadd45α in human early placenta and its role in trophoblast invasion

Objectives

Well-controlled trophoblast migration and invasion at the maternal–foetal interface are crucial events for normal placentation and successful pregnancy. Growing evidence has revealed that growth arrest and DNA damage-inducible 45 alpha (Gadd45α) participates in tumour migration and invasion as a tumour suppressor. However, the expression and function of Gadd45α in trophoblasts is unknown. This study aimed to determine the Gadd45α expression and function in the human first trimester placenta and identify the underlying mechanisms.

Methods

The expression of Gadd45α in human first trimester placenta was determined using immunohistochemistry. HTR8/SVneo cell line was used to investigate the effects of Gadd45α on proliferation, apoptosis, migration/invasion, matrix metalloproteinase (MMP)2/9 activities, and tissue inhibitor of metalloproteinase (TIMP)1/2 expression using cell proliferation assays, flow cytometric analysis, transwell migration/invasion assays, gelatin gel zymography, and western blotting, respectively. Moreover, a placental villous explant model was employed to verify its functions in placentation.

Results

Gadd45α was strongly expressed in syncytiotrophoblasts and trophoblast columns of human placental villi, extravillous trophoblast cells and glandular epithelium within the maternal decidua. Gadd45α knockdown significantly promoted migration and invasion of HTR8/SVneo cells, whereas it did not affect cell proliferation or apoptosis. Silencing Gadd45α also enhanced trophoblast outgrowth and migration in placental explants. These effects were related to increased activities of MMP2/9 and the decreased expression of TIMP1/2.

Discussion and conclusion

Gadd45α may be involved in human trophoblast migration and invasion and may function as an important negative regulator at the foetal–maternal interface during early pregnancy by directly or indirectly regulating MMP2/9 activities.     

Oxidative stress-induced Gadd45α inhibits trophoblast invasion and increases sFlt1/sEng secretions via p38 MAPK involving in the pathology of pre-eclampsia

Background: Pre-eclampsia (PE) is one of the most common pregnancy-related complications. We have previously reported that growth arrest and DNA damage-inducible 45 alpha (Gadd45α) is over-expressed in trophoblasts in pre-eclamptic placentas, with an excessive activation of p38 mitogen-activated protein kinase (MAPK) and increased levels of soluble Fms-like tyrosine kinase 1 (sFlt-1) and soluble endoglin (sEng) in maternal sera. Now we further investigate how Gadd45α regulates trophoblast functions and anti-angiogenesis factors secretions during placental development in patients with PE.

Methods: Human placental villous explants were used to verify the effects of Gadd45α and p38 MAPK in placentation. Then HRT8/SVneo cells exposed to hypoxia/reoxygenation (H/R) were employed as an oxidative stress model to investigate the effects of Gadd45α on invasion and sFlt-1/sEng secretions. Through silencing Gadd45α with lentiviral vector-based short-hairpin RNA and inhibiting p38 MAPK with SB203580, we demonstrated that Gadd45α and its downstream p38 protein played roles in the pathology of pre-eclampsia.

Results: Gadd45α was found to have increased expression in H/R-treated villous explants and HTR8/SVneo cells. Gadd45α knockdown or p38 blockage could promote trophoblast outgrowth and migration in H/R-exposed villous explants, and enhance the potentials of trophoblast migration/invasion and network formation in H/R-exposed HTR8/SVneo cells. These functional changes might be related to the increased activities of MMP2/9. Meanwhile, Gadd45α knockdown or p38 inhibition also decreases sFlt-1/sEng secretions via suppressing oxidative stress.

Conclusions: Oxidative stress-induced overexpression of Gadd45α might influence the activity of MMPs through activation of p38 MAPK signaling to affect the invasion of trophoblast cells, and increase the secretions of sFlt-1/sEng, which then participate in the pathogenesis of pre-eclampsia.     

Matrix metalloproteinases and their inhibitors in gestational trophoblastic diseases and normal placenta.

OBJECTIVE: Our purpose was to investigate the expression of matrix metalloproteinases (MMPs) in gestational trophoblastic diseases and normal first-trimester placenta. METHODS: Paraffin sections of 16 partial moles, 25 complete moles, 10 gestational choriocarcinomas, and 11 normal first-trimester placentas were studied immunohistochemically for expression of MMP-1, MMP-2, MMP-3, MMP-9, MMP-13, and tissue inhibitor of metalloproteinase-1 (TIMP-1). RESULTS: Nine (90.0%) of the choriocarcinoma cases showed strong intensity of staining for MMP-1. Choriocarcinoma exhibited significantly stronger staining for MMP-1 than syncytiotrophoblast in normal placenta (P < 0.01), partial mole (P < 0.01), and complete mole (P < 0.01). Choriocarcinoma also showed significantly stronger staining for MMP-1 than the extravillous trophoblast in placenta (P < 0.05). MMP-2 was expressed only in syncytio- and extravillous trophoblasts in normal placenta, partial mole, and complete mole. Choriocarcinoma and the extravillous trophoblast in partial mole and complete mole had significantly stronger staining for MMP-2 than the extravillous trophoblast in placenta (P < 0.05, P < 0.01, P < 0.01, respectively). Choriocarcinoma also exhibited significantly stronger staining for MMP-2 than syncytiotrophoblasts in placenta (P < 0.01), partial mole (P = 0.05), and complete mole (P < 0.01). The expression of MMP-3, MMP-9, and MMP-13 was similar in all four tissues with the predominance of syncytiotrophoblast for MMP-3 and MMP-13 and cytotrophoblast for MMP-9. While 8 (73.0%) placentas, 14 (87.5%) partial moles, and 19 (76.0%) complete moles showed strong immunoreactivity for TIMP-1 in syncytiotrophoblasts, no strong staining was found in choriocarcinomas (P < 0.01, P < 0.01, P < 0.01, respectively). CONCLUSION: The extravillous trophoblast of first-trimester placenta has significantly less expression of MMP-1 than choriocarcinoma and significantly less expression of MMP-2 than choriocarcinoma and extravillous trophoblast of partial and complete mole. The expression of TIMP-1 was significantly less in choriocarcinoma than the syncytiotrophoblast of normal placenta, partial mole, and complete mole. MMPs and their inhibitors may play a role in the pathogenesis of gestational trophoblastic diseases.     

Promoter hypomethylation and increased maspin expression in preeclamptic placentas in a Chinese population

ObjectivePreeclampsia is thought to begin with shallow trophoblast invasion and inadequate spiral artery remodeling. Maspin, a tumor-suppressor gene, plays a regulatory role in trophoblast invasion and motility. The tissue-specific methylation of the maspin promoter can regulate maspin gene expression in various cancers. We sought to detect maspin gene expression and assess the degrees of methylation of maspin promoter regions in preeclamptic placentas in the Han Chinese population and to investigate the potential role of maspin in the pathophysiology of preeclampsia.MethodsWe conducted RT-PCR, immunohistochemistry and western blotting to characterize maspin gene expression and protein levels in the placentas from normal and preeclamptic pregnancies. Finally, using methylation-specific PCR and bisulfite sequencing PCR, we detected the degrees of methylation of the promoter regions of maspin in each of the two studied groups.ResultsMaspin expression was increased at the mRNA and protein levels in the preeclamptic placentas compared to the control group. Maspin immunohistochemical staining revealed positive staining in the syncytio-cytotrophoblast layers and more diffuse staining in the preeclamptic group. The mean methylation level of the analyzed promoter region was significantly hypomethylated in the preeclamptic placentas compared to the control placentas, pointing to a negative relationship between maspin promoter methylation and gene expression.DiscussionHypomethylation of the maspin promoter results in increased expression of maspin in preeclamptic placentas, which suggests a negative relationship between maspin methylation and maspin expression in this Han Chinese population. Thus, maspin is likely involved in the etiology of preeclampsia.