Altered Global Gene Expression in First Trimester Placentas of Women Destined to Develop Preeclampsia

BackgroundPreeclampsia is a pregnancy-specific disorder that remains a leading cause of maternal, fetal and neonatal morbidity and mortality, and is associated with risk for future cardiovascular disease. There are no reliable predictors, specific preventative measures or treatments other than delivery. A widely held view is that the antecedents of preeclampsia lie with impaired placentation in early pregnancy. Accordingly, we hypothesized dysregulation of global gene expression in first trimester placentas of women who later manifested preeclampsia.MethodsSurplus chorionic villus sampling (CVS) tissues were collected at 10–12 weeks gestation in 160 patients with singleton fetuses. Four patients developed preeclampsia, and their banked CVS specimens were matched to 8 control samples from patients with unaffected pregnancies. Affymetrix HG-U133 Plus 2.0 GeneChips were utilized for microarray analysis. Naïve Bayes prediction modeling and pathway analysis were conducted. qRT-PCR examined three of the dysregulated genes.ResultsThirty-six differentially expressed genes were identified in the preeclampsia placentas. qRT-PCR verified the microarray analysis. Thirty-one genes were down-regulated. Many were related to inflammation/immunoregulation and cell motility. Decidual gene dysregulation was prominent. No evidence was found for alterations in hypoxia and oxidative stress regulated genes.ConclusionsTo our knowledge, this is the first study to show dysregulation of gene expression in the early placentas of women ～6 months before developing preeclampsia, thereby reinforcing a placental origin of the disorder. We hypothesize that placentation in preeclampsia is compromised in the first trimester by maternal and fetal immune dysregulation, abnormal decidualization, or both, thereby impairing trophoblast invasion. Several of the genes provide potential targets for the development of clinical biomarkers in maternal blood during the first trimester. Supplementary materials are available for this article via the publisher's online edition.     

Placental expression of sFlt-1 and PlGF in early preeclampsia vs. early IUGR vs. age-matched healthy pregnancies

Objective: To investigate whether differences between early preeclampsia and early fetal growth restriction can be explained by differential placental expression patterns of sFlt-1, Flt-1, and PlGF. Methods: Placental tissues and maternal blood samples from six cases of preeclampsia, seven IUGR, and six age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity. Results: Neither placental PlGF mRNA and protein expression nor placental villous trophoblast expression intensity of PlGF was altered by placental dysfunction. Conclusion: High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.     

Leptin Expression in Primary Trophoblast Cells in Response to Incubation with the Serum of Preeclamptic Women

Objective. We investigated whether the increase of leptin expression in preeclamptic placentas is additionally influenced by soluble maternal factors under hypoxic and nonhypoxic conditions. Methods. Term trophoblast cells were isolated and stimulated with sera from preeclamptic women under normoxic or hypoxic conditions. Levels of leptin mRNA and protein were evaluated by real-time RT-PCR or ELISA and Western blot analysis. Results. Leptin concentrations were increased in the serum of patients with preeclampsia and gestational diabetes. Hypoxia, insulin, and dexamethasone induced leptin expression in trophoblast cells. The incubation with sera from preeclamptic women led to a small, though, significant, increase of leptin gene expression. The effect of preeclamptic serum on leptin gene expression in trophoblast cells was lost under hypoxia. The serum of women with gestational diabetes did not increase leptin expression neither in normoxic nor hypoxic primary trophoblast cells. Conclusion. Our results can not exclude a soluble maternal factor in the serum of women with preeclampsia accounting for increased leptin expression in placental tissue in addition to hypoxia. However, an important biological role of this small increase in nonhypoxic conditions does not seem very likely.     

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.     

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.     

Increased placental sFlt-1 but unchanged PlGF expression in late-onset preeclampsia

Objective: To investigate whether differences between late-onset preeclampsia (PE) and intrauterine growth restriction (IUGR) can be explained by differential placental expression patters of sFlt-1, Flt-1, and placental growth factor (PlGF).

Methods: Placental tissues and maternal blood samples from seven patients with PE, five IUGR, and seven age-matched controls were studied for mRNA and protein levels as well as protein localization and expression intensity.

Results: Placental PlGF mRNA and protein expression were not altered by placental dysfunction while placental villous trophoblast expression intensity of PlGF was increased.

Conclusion: High sFlt-1 concentrations may account for diminished maternal serum PlGF levels.     

ALX-R在子痫前期患者胎盘组织中的表达及其与NF-κB p65的相关性

目的:观察子痫前期(PE)患者胎盘组织中脂氧素A4受体(ALX-R)、核因子-κB p65(NF-κB p65)表达的变化,探讨两者在PE发生发展中的作用及相关性。方法:采用RT-PCR方法、免疫组化法检测PE组(轻度10例、重度20例)与对照组(20例)孕妇胎盘组织中ALX-R、NF-κB p65 mRNA和蛋白的表达水平。结果:(1)胎盘组织中ALX-RmRNA表达水平随病情严重程度而明显下降,重度PE组低于轻度PE组、对照组(P<0.01);NF-κB p65 mRNA表达水平随病情严重程度而升高,重度PE组高于轻度PE组、对照组(P<0.05);(2)胎盘组织中PE组ALX-R蛋白的表达强度低于对照组(P<0.01);PE组NF-κB p65蛋白的表达强度高于对照组(P<0.01);(3)重度与轻度PE组胎盘组织中ALX-R与NF-κB p65的mRNA和蛋白表达水平无明显相关性;对照组胎盘组织中ALX-R与NF-κB p65的mRNA和蛋白表达水平呈负相关(r=-0.86,P<0.01;r=-0.63,P<0.01)。结论:ALX-R与NF-κB p65的表达,可能与PE发生发展的病理生理过程密切相关。     

激活素A和卵泡休止素与先兆子痫的相关性研究

目的　探讨先兆子痫患者血清中激活素A和卵泡休止素水平及其mRNA在胎盘组织中的表达 ,及其与先兆子痫发病的关系。方法　 2 0例足月妊娠先兆子痫孕妇作为先兆子痫组 ,2 0例足月妊娠血压正常孕妇作为对照组。应用酶联免疫吸附试验 (ELISA)检测两组孕妇血清中激活素A和卵泡休止素水平。应用半定量逆转录 聚合酶链反应 (RT PCR)技术检测两组孕妇分娩后胎盘组织中激活素AmRNA和卵泡休止素mRNA的相对表达强度。将两组孕妇的胎盘组织激活素AmRNA的表达强度与血清激活素A水平进行直线相关分析。结果　 (1)先兆子痫组孕妇血清中激活素A水平为 (33 7± 6 6 ) μg/L ,明显高于对照组的 (9 9± 2 1) μg/L(P <0 0 1)。先兆子痫组孕妇血清中卵泡休止素水平为 (5 1± 0 6 ) μg/L ,与对照组的 (4 7± 0 3) μg/L比较 ,差异无显著性 (P >0 0 5 )。 (2 )先兆子痫组胎盘组织中激活素AmRNA为 1 11± 0 2 1,明显高于对照组的 0 6 1± 0 17(P <0 0 1)。先兆子痫组胎盘组织中卵泡休止素mRNA为 0 5 7± 0 31,与对照组的 0 5 4± 0 2 7比较 ,差异无显著性 (P >0 0 5 )。(3)在先兆子痫组和对照组孕妇中 ,血清中激活素A水平与胎盘组织激活素AmRNA相对表达强度呈正相关 [相关系数 (r) =0 89,P <0 0 1]。结论     

Increased expression levels of E-cadherin,cytokeratin 18 and 19 observed in preeclampsia were not correlated with disease severity

Introduction

Preeclampsia is a pregnancy-specific disorder and placental factor(s) contribute to the pathogenesis of preeclampsia. Turnover of villous trophoblast is affected by impaired placental perfusion in preeclampsia. Expression and localisation of cadherins and cytokeratins are involved in the pathogenesis of preeclampsia. However, studies describing the associations between cadherins and cytokeratins in preeclampsia are limited. The aim of this study was to investigate the expression of E-cadherin, N-cadherin, cytokeratin 18 and cytokeratin 19 in placentae from women with preeclampsia in order to determine whether their expression differs with disease severity.

Methods

29 preeclamptic placentae and 25 normotensive placentae were included in this study. The expression of E-cadherin, cytokeratin 18, cytokeratin 19 andN-cadherin was quantified by immunohistochemistry and western blotting.

Results

E-cadherin, cytokeratin 18 and cytokeratin 19 were expressed predominantly in the syncytiotrophoblast of the placenta and the expression of E-cadherin, cytokeratin 18 and cytokeratin 19 was significantly increased in preeclampsia compared to normotensive pregnancies. However, there was no significant difference in expression between severe preeclampsia and mild preeclampsia. In addition, there was no difference in the expression of N-cadherin between preeclampsic and normotensive pregnancies.

Discussion

Our data demonstrated increased expression of E-cadherin, cytokeratin 18 and cytokeratin 19 in the syncytiotrophoblast of preeclamptic placentae, but this increase was not correlated with disease severity.

Conclusion

Our data suggests that E-cadherin and cytokeratins are involved in the pathogenesis of preeclampsia.     

Clinical risk factors for preeclampsia

Preeclampsia, diagnosed by increased blood pressure and de novo proteinuria, is a pregnancy-specific disease associated with a high incidence of maternal and fetal morbidity and mortality. Identification of women at risk for this potential life threatening disease might enable the clinician to identify and counsel patients adequately. A major concern in the identification of clinical risk factors for the development of preeclampsia is confusion over the clinical classification of this syndrome which has resulted from using different definitions. For this in-depth review and meta-analysis only well defined reports were selected. Maternal constitutional and environmental factors as well as pregnancy-specific changes as risk factors for the development of preeclampsia were studied. This review describes both dependent and the following independent risk factors for the development of preeclampsia: chronic hypertension, renal disease, diabetes, nulliparity, and long pregnancy interval.     

Decreased tryptophan catabolism by placental indoleamine 2,3-dioxygenase in preeclampsia

OBJECTIVE: Tryptophan degradation and depletion resulting from activation of indoleamine 2,3-dioxygenase is characteristic of inflammatory reactions and may control their intensity. Normal third-trimester pregnancy is characterized by a maternal systemic inflammatory response, which is more intense in preeclampsia. Therefore, we studied tryptophan metabolism in pregnant women, with or without preeclampsia, as well as expression and function of placental indoleamine 2,3-dioxygenase. STUDY DESIGN: Plasma concentrations of tryptophan and kynurenine in women with preeclampsia, appropriately matched women with normal pregnancy, and healthy nonpregnant women were measured. Placental enzymatic activity and messenger RNA (mRNA) expression level of indoleamine 2,3-dioxygenase were determined from the same placental material. Peripheral blood mononuclear cell proliferation was determined in medium conditioned by prior culture with villous tissue. RESULTS: The plasma ratio of kynurenine to tryptophan, an in vivo index of enzyme activity, was significantly increased compared with nonpregnant controls in normal pregnancy but not in preeclampsia. The activity and mRNA expression level of indoleamine 2,3-dioxygenase in term placentas were significantly lower in preeclampsia. Medium conditioned by culture of villous tissue explants of preeclampsia was less effective in inhibiting peripheral blood mononuclear cell proliferation compared with that of normal pregnancy. CONCLUSION: These observations suggest that in preeclampsia, reduced placental indoleamine 2,3-dioxygenase activity (and relatively elevated plasma tryptophan) could cause dysregulation of the inflammatory response that is intrinsic to normal pregnancy. This may contribute to the pathogenesis of the maternal syndrome of preeclampsia.     

Angiopoietin-2: A Promising Indicator for the Occurrence of Severe Preeclampsia

Background. The known connection between placental hypoxia and the development of preeclampsia suggests that angiogenic factors in the placenta would be changed and affect the maternal and/or umbilical cord plasma levels in patients with preeclampsia. Objective. The aim of this study was to determine the difference and correlation of placental mRNA expression and maternal/umbilical cord plasma concentrations of vascular endothelial growth factor A (VEGF-A), angiopoietin-1, and angiopoietin-2 between women with severe preeclampsia and normal pregnancies. Methods. Sixteen patients with severe preeclampsia and 29 normotensive pregnant women were studied. The placental mRNA expression was assessed using real-time quantitative RT-PCR analysis. Maternal/umbilical cord plasma levels were measured using an enzyme-linked immunoassay. Nonparametric methods were applied for statistical analysis. Results. Placental mRNA expression of angiopoietin-2 was significantly increased in patients with severe preeclampsia (p < 0.001). The maternal plasma angiopoietin-2 protein level was also significantly increased in women with severe preeclampsia (p < 0.05) and showed a positive correlation with the placental mRNA expression of angiopoietin-2 (r = 0.54, p < 0.005). For VEGF-A and angiopoietin-1, there were no significant differences between the two groups. A maternal plasma angiopoietin-2 concentration of 8.4 ng/mL had a sensitivity of 63% and a specificity of 83% for predicting severe preeclampsia. Conclusion. Placental angiopoietin-2 mRNA expression was increased and correlated with the maternal plasma angiopoietin-2 protein concentration in women with severe preeclampsia. This suggests that the plasma angiopoietin-2 protein level may be a candidate marker for severe preeclampsia.     

Stimulation of hCG protein and mRNA in first trimester villous cytotrophoblast cells in vitro by glycodelin A

AIM: Human chorionic gonadotropin (hCG) is produced by fetal trophoblast cells and secreted into maternal circulation mainly in the first trimester of pregnancy. Another glycoprotein, glycodelin A, is one of the main products of the maternal decidua during this period. The purpose of this study was to investigate the effect of glycodelin A on hCG release by isolated cytotrophoblast cells in vitro. METHODS: Cytotrophoblast cells were prepared from human first trimester placenta and incubated with varying concentrations of glycodelin A. Supernatants were assayed for hCG protein concentrations, and quantification of beta hCG mRNA was carried out by RT-PCR. Expression of hCG was analysed in stimulated trophoblast cells and in unstimulated controls by immunocytochemistry. RESULTS: Glycodelin A induces a dose-dependent increase of hCG production. An increase of hCG expression was measured at 100 and 200 microg/mL glycodelin-A treatment in trophoblast cell culture by TaqMan assay on mRNA level. We found a moderate staining of hCG in control trophoblast cells, whereas a strong hCG staining was seen in glycodelin A-treated trophoblast cells. CONCLUSIONS: HCG is a marker for the differentiation process of trophoblast cells. Our results suggest that glycodelin A secreted by the decidualized endometrium is involved in the regulation of hormones produced by the trophoblast.     

胎盘组织中尿皮素和促肾上腺皮质激素释放激素2β受体表达变化与先兆子痫发病的关系

目的探讨先兆子痫患者胎盘组织中尿皮素(UCN)和促肾上腺皮质激素释放激素2β受体(CRH R2β)表达与先兆子痫发病的关系。方法应用半定量RT PCR技术测定20例先兆子痫患者(先兆子痫组)和20例正常妊娠妇女(对照组)胎盘组织中UCNmRNA和CRH R2βmRNA的水平;采用免疫组化方法对UCN进行蛋白定位和半定量分析。结果(1)先兆子痫组胎盘组织中UCNmRNA的表达水平为1 14±0 26,高于对照组的0 78±0 46,两组比较,差异有统计学意义(P<0 05)。(2)先兆子痫组胎盘组织中CRH R2βmRNA的表达水平为0 89±0 33,与对照组的0 93±0 50比较,差异无统计学意义(P>0 05)。(3)免疫组化定位结果显示,两组产妇的UCN蛋白表达主要位于合体滋养细胞,少量表达于细胞滋养细胞和血管内皮细胞。蛋白半定量结果显示,UCN在先兆子痫组胎盘合体滋养细胞中的表达强度高于对照组,两组比较,差异有统计学意义(P<0 05 )。结论先兆子痫患者胎盘组织中UCN表达水平升高,而CRH R2β水平则无明显变化,因此UCN的作用加强。这可能是胎盘组织对母体和胎儿应激状态的一种继发性代偿反应,并参与先兆子痫的病理生理过程。     

A semi-quantitative microarray method to detect fetal RNAs in maternal plasma

OBJECTIVES: To set up a semi-quantitative microarray method for the detection of fetal RNAs in maternal plasma. METHODS: We developed a semi-quantitative microarray method for the detection of placental RNA in maternal plasma. Firstly, the selected fetal RNAs were linearly amplified from the maternal plasma and then fluorescently labeled as the target DNAs. Finally, the targets were hybridized and detected by capturing DNA probes on a microarray slide. Two genes of beta subunit of human chorionic gonadotrophin (beta-hCG) and zinc finger gene on the Y chromosome (ZFY) were assayed with the microarray, and beta actin gene was used as an internal standard. Eighty-five pregnant women in the first trimester and the third trimester of gestation joined in this experiment, 14 of them also sampling in 36 h after delivery for the same assay. Real-time quantitative PCR was performed for comparison. RESULTS: It was found that the mRNA level of beta-hCG decreased with the increasing of gestation age, and it was much higher in the carriers of the female fetus than in the carriers of the male fetus in the first trimester of gestation, which was consistent with the real-time quantitative PCR results. The results also reveal that delivery would result in the clearance of fetal mRNA in maternal plasma. CONCLUSIONS: The results suggest that the semi-quantitative microarray method has great potential as a high-throughput assay in prenatal diagnosis and clinical laboratory.     

子痫前期患者血浆中sTRAIL、胎盘组织TRAIL及TRAIL受体的变化及意义

目的:研究子痫前期(PE)患者血浆s TRAIL及胎盘滋养细胞上TRAIL/TRAIL-Rs的变化及其与PE发病的关系。方法:选取56例PE患者为研究对象,其中符合重度PE诊断标准者31例(研究组1),未及重度PE 25例(研究组2)。选取同期正常妊娠妇女为对照组,其中28~36周30例(对照组1)、36~(+1)~38周30例(对照组2),因胎膜早破、早产等于28~36周分娩者27例(对照组3),36~(+1)~38周分娩者30例(对照组4)。研究组孕妇留取静脉血及胎盘组织,对照组1、2留取静脉血,对照组3、4留取胎盘组织。ELISA法检测血浆中TRAIL含量,免疫组化法检测胎盘组织中TRAIL和TRAIL-Rs(DR4、DR5、DcR1、DcR2)含量。结果:研究组血浆中sTRAIL含量明显低于对照组(研究组1 vs对照组1,P0.001;研究组2 vs对照组2,P0.005);随着病情加重,s TRAIL含量明显下降(P0.05)。研究组胎盘组织中TRAIL表达明显减少,随着病情加重而加重。研究组中死亡受体DR4、DR5的含量明显高于对照组,而诱骗受体DcR1、DcR2含量明显低于对照组。PE重度组中DR4、DR5含量高于轻度组(P0.05),DcR1和DcR2含量则无显著差异。结论:PE患者血浆中sTRAIL及胎盘组织中TRAIL/TRAIL-Rs含量发生了明显变化,TRAIL/TRAIL-Rs的不平衡性参与了PE的病理过程。