A Proteomic Analysis of Placental Trophoblastic Cells in Preeclampsia–Eclampsia

To explore the proteomic changes of placental trophoblastic cells in preeclampsia–eclampsia (PE), placental trophoblastic cells from normally pregnant women and women with hypertension during gestational period were prepared by laser capture microdissection (LCM), and proteins isolated from these cells were subjected to labeling and proteolysis with isotope-coded affinity tag reagent. A qualitative and quantitative analysis of the proteome expression of placental trophoblastic cells was made using two-dimensional liquid chromatography tandem mass spectrometry (2D LC–MS/MS). A total of 831 proteins in placental trophoblastic cells were identified by combined use of LCM technique and 2D LC–MS/MS. The result was superior to that of conventional two-dimensional electrophoresis method. There were marked differences in 169 proteins of placental trophoblastic cells between normally pregnant women and women with PE. Of 70 (41.4 %) proteins with more than twofold differences, 31 proteins were down-regulated, and 39 were up-regulated in placental trophoblastic cells of the woman with PE. Laminin expression in placenta trophoblastic cells of women with PE was significantly down-regulated as confirmed by Western blot analysis. These findings provide insights into the proteomic changes in placental trophoblastic cells in response to PE and may identify novel protein targets associated with the pathogenesis of PE.     

miR-19a在正常妊娠及重度子痫前期患者胎盘中的表达

目的：通过检测正常妊娠及重度子痫前期患者胎盘组织中miR-19a的表达,探讨其与子痫前期发病的关系。方法：收集10例重度子痫前期患者胎盘组织（实验组）和10例正常产妇胎盘组织（对照组）,应用荧光实时定量PCR（Real Time PCR）的方法检测两组miR-19a的表达差异。结果：重度子痫前期患者胎盘组织中miR-19a表达升高（P〈0.05）。结论：子痫前期患者胎盘组织中存在差异表达的miRNA,miR-19a在胎盘组织中的高表达可能与子痫前期的发病有关。     

miR-19a 在正常妊娠及重度子痫前期患者胎盘中的表达

目的:通过检测正常妊娠及重度子痫前期患者胎盘组织中miR-19a的表达,探讨其与子痫前期发病的关系。方法:收集10例重度子痫前期患者胎盘组织(实验组)和10例正常产妇胎盘组织(对照组),应用荧光实时定量PCR(Real Time PCR)的方法检测两组miR-19a的表达差异。结果:重度子痫前期患者胎盘组织中miR-19a表达升高(P<0.05)。结论:子痫前期患者胎盘组织中存在差异表达的miRNA,miR-19a在胎盘组织中的高表达可能与子痫前期的发病有关。     

Involvement of placental peptidases associated with renin-angiotensin systems in preeclampsia

Preeclampsia is characterized by pregnancy-induced hypertension accompanied with protein urea and generalized edema. Preeclampsia develops during the second half of pregnancy and resolves postpartum promptly, implicating the placenta as a primary cause in the disorder. Normal pregnancy is associated with reductions in arterial pressure and attenuated pressor response to exogenous infused angiotensin II (ANG II). In contrast, women with preeclampsia show the similar sensitivity to the pressor effect of ANG II as do non-pregnant women. To elucidate the involvement of placental peptidases associated with renin-angiotensin systems, we determined the localization of angiotensin-converting enzyme (ACE) and aminopeptidase A (AP-A), ANG II degrading enzyme, in the placenta and compared the expression of mRNA and protein in uncomplicated and preeclamptic placenta. In addition, AP-A expression in trophoblastic cells treated with ANG II and ACE expression in HUVECs under hypoxic condition were analyzed, respectively. The expression of both peptidases in the preeclamptic placenta was significantly higher than those from uncomplicated. ACE was primarily localized to venous endothelial cells of stem villous whereas AP-A expression was recognized in the trophoblast and pericytes of fetal arterioles and venules within stem villous. Hypoxia induced ACE expression in HUVECs while both hypoxia and ANG II evoked AP-A expression in trophoblast. These results suggested that hypoxic condition in preeclampsia induces ACE activation in feto-placental unit to maintain the fetal hemodynamics and placental AP-A plays a role as a component of the barrier of ANG II between mother and fetus.     

Involvement of placental peptidases associated with renin–angiotensin systems in preeclampsia

Preeclampsia is characterized by pregnancy-induced hypertension accompanied with protein urea and generalized edema. Preeclampsia develops during the second half of pregnancy and resolves postpartum promptly, implicating the placenta as a primary cause in the disorder. Normal pregnancy is associated with reductions in arterial pressure and attenuated pressor response to exogenous infused angiotensin II (ANG II). In contrast, women with preeclampsia show the similar sensitivity to the pressor effect of ANG II as do non-pregnant women. To elucidate the involvement of placental peptidases associated with renin–angiotensin systems, we determined the localization of angiotensin-converting enzyme (ACE) and aminopeptidase A (AP-A), ANG II degrading enzyme, in the placenta and compared the expression of mRNA and protein in uncomplicated and preeclamptic placenta. In addition, AP-A expression in trophoblastic cells treated with ANG II and ACE expression in HUVECs under hypoxic condition were analyzed, respectively. The expression of both peptidases in the preeclamptic placenta was significantly higher than those from uncomplicated. ACE was primarily localized to venous endothelial cells of stem villous whereas AP-A expression was recognized in the trophoblast and pericytes of fetal arterioles and venules within stem villous. Hypoxia induced ACE expression in HUVECs while both hypoxia and ANG II evoked AP-A expression in trophoblast. These results suggested that hypoxic condition in preeclampsia induces ACE activation in feto-placental unit to maintain the fetal hemodynamics and placental AP-A plays a role as a component of the barrier of ANG II between mother and fetus.     

Expression of osteoprotegerin in placenta and its association with preeclampsia

Background

Osteoprotegerin (OPG), a key regulatory factor in bone metabolism, was documented also a potential pro-angiogenic factor, which acts an important role in protecting vascular endothelial cells. Since preeclampsia has gradually been employed to be vascular diseases, we speculated that OPG might be associated with preeclampsia. The study was to evaluate the level of OPG protein and mRNA in placenta, and investigate the relationship between OPG and the pathogenesis of preeclampsia.

Methodology/Principal Findings

Placental specimens from 30 term normal pregnancy, 30 severe preeclampsia and 30 mild cases were studied. The expression and levels of OPGs’ protein and mRNA were detected by immunohistochemisty, western blot analysis and real-time quantitative PCR analysis respectively. The expression of OPG protein was found in cytoplasm of placenta cytotrophoblasts and syncytiotrophoblasts in three groups. There were no significant differences of OPG protein between the maternal and fetal side in each group. The OPG protein and mRNA levels in severe preeclampsia were significantly higher than those in mild cases and normal pregnancy. However, there were no markedly differences of the OPG protein and mRNA levels between term delivery and preterm delivery in severe cases. In preeclampsia, the OPG protein and mRNA level was positively correlated with systolic blood pressure and 24 h urinary protein respectively.

Conclusions/Significance

OPG protein and mRNA level in placentas of preeclampsia were found abnormal compared with normal pregnancy. In preeclampsia, the OPG protein and mRNA levels were closely related with its important clinical parameters. Taken together, OPG might be closely correlated with the pathogenesis of preeclampsia.     

Folate-related processes in human placenta: gene expression, aminothiols, proliferation and apoptosis

The paper contains short information concerning the role of folate-related processes in cell metabolism and multiple diseases which are characterized by hyperhomocysteinemia. The authors represent more detailed information about the folate-related processes in human placenta, namely about the content of aminothiols at different allelic variants of placental methylenetetrahydrofolate reductase during the course of physiological pregnancy and preeclampsia. The existing data concerning the expression and catalytic activity of corresponding enzymes are corroborated by the authors' own results that proved for the first time the functional activity of transsulfuration pathway in human placenta. This pathway is activated in placental explants in parallel with down-regulation of proliferation and up-regulation of apoptosis when hyperhomocysteinemia is imitated by high concentration of homocysteine in culture medium. On the whole the presented data point to the importance of placental folate-related processes for its normal function.     

Maternal diabetes affects cell proliferation in developing rat placenta

Placentation starts with the formation of a spheroidal trophoblastic shell surrounding the embryo, thus facilitating both implantation into the uterine stroma and contact with maternal blood. Although it is known that diabetes increases the placental size and weight, the mechanisms responsible for this alteration are still poorly understood. In mammals, cellular proliferation occurs in parallel to placental development and it is possible that diabetes induces abnormal uncontrolled cell proliferation in the placenta similar to that seen in other organs (e.g. retina). To test this hypothesis, the objective of this work was to determine cell proliferation in different regions of the placenta during its development in a diabetic rat model. Accordingly, diabetes was induced on day 2 of pregnancy in Wistar rats by a single injection of alloxan (40 mg/kg i.v.). Placentas were collected on days 14, 17, and 20 postcoitum. Immunoperoxidase was used to identify Ki67 nuclear antigen in placental sections. The number of proliferating cells was determined in the total placental area as well as in the labyrinth, spongiotrophoblast and giant trophoblast cell regions. During the course of pregnancy, the number of Ki67 positive cells decreased in both control and diabetic rat placentas. However, starting from day 17 of pregnancy, the number of Ki67 positive cells in the labyrinth and spongiotrophoblast regions was higher in diabetic rat placentas as compared to control. The present results demonstrate that placentas from the diabetic rat model have a significantly higher number of proliferating cells in specific regions of the placenta and at defined developmental stages. It is possible that this increased cell proliferation promotes thickness of the placental barrier consequently affecting the normal maternal-fetal exchanges.     

Distribution of Notch protein members in normal and preeclampsia-complicated placentas

Notch proteins are a transmembrane receptor family that is structurally and functionally conserved from worms to humans. The mammalian family of Notch proteins consists of several genes encoding Notch receptors and related Notch ligands. Notch signaling is involved in different aspects of the cell-fate decision tree: differentiation, proliferation, and apoptosis. These three processes are finely regulated in human placenta in order to allow a successful pregnancy and correct fetal growth. Notch and its ligands also participate in vascular remodeling and stabilization. Vasculogenesis and blood regulation are of importance in the human placenta for normal fetal development and growth; any disorder of these systems leads to preeclampsia. Drawing on this background, we have investigated the expression of Notch-1, Notch-4, and Jagged-1, together with two members related to the Notch pathway in angiogenesis: VEGF and p21. Normal and preeclamptic human placentas have been evaluated by immunohistochemistry. In preeclamptic samples, a down-regulation of Notch pathway members occurs with a weak/moderate expression of the Notch protein members in all components of placenta compared with physiological placentas that, at term, exhibit the strong expression of Jagged-1 and a moderate expression of both Notch-1 and Notch-4 in all compartments of the placental villi. Moreover, preeclamptic samples also reveal a down-regulation of VEGF expression, together with a moderate nuclear expression of p21^Cip1 in the syncytiotrophoblast, cytotrophoblast, and endothelial cells. This down-regulation of VEGF in preeclamptic placentas, in turn, probably decreases Notch protein expression in placental compartments and in endothelial cells and could offer an ethiopathogenetic explanation for the onset of this pathology.     

IL-4 和IFN-γ mRNA 在子痫前期患者胎盘组织中的表达及意义

目的:检测胎盘组织中IFN-γ和IL-4的表达,探讨IFN-γ和IL-4在子痫前期的发病中的作用.方法:采用原位杂交法检测了20例正常妊娠孕妇和34例子痫前期组(包括16例轻度和18例重度)中的IFN-γ、IL-4 mRNA的表达水平,并通过图像分析系统对染色结果进行定量分析.结果:(1)IL-4 mRNA的表达在正常妊娠组、子痫前期轻度组和子痫前期重度组的表达无差异(P＞0.05).(2)与正常妊娠组、子痫前期轻度组相比,子痫前期重度组IFN-γ mRNA的表达有差异性(P＜0.05);子痫前期轻度组与正常妊娠组相比无差异(P＞0.05).(3)与正常妊娠组相比,子痫前期轻度组、重度组IFN-γ mRNA/IL-4 mRNA的比值均有差异性(P＜0.05),且随病情的加重比值增大.结论:Th1/Th2细胞因子的平衡偏离可能是导致子痫前期发病的病因之一.     

Chlamydia heat shock protein 60 induces trophoblast apoptosis through TLR4

Intrauterine infection affects placental development and function, and subsequently may lead to complications such as preterm delivery, intrauterine growth retardation, and preeclampsia; however, the molecular mechanisms are not clearly known. TLRs mediate innate immune responses in placenta, and recently, TLR2-induced trophoblast apoptosis has been suggested to play a role in infection-induced preterm delivery. Chlamydia trachomatis is the etiological agent of the most prevalent sexually transmitted bacterial infection in the United States. In this study, we show that in vitro chlamydial heat shock protein 60 induces apoptosis in primary human trophoblasts, placental fibroblasts, and the JEG3 trophoblast cell line, and that TLR4 mediates this event. We observed a host cell type-dependent apoptotic response. In primary placental fibroblasts, chlamydial heat shock protein 60-induced apoptosis was caspase dependent, whereas in JEG3 trophoblast cell lines it was caspase independent. These data suggest that TLR4 stimulation induces apoptosis in placenta, and this could provide a novel mechanism of pathogenesis for poor fertility and pregnancy outcome in women with persistent chlamydia infection.     

Coenzyme Q10 is increased in placenta and cord blood during preeclampsia

Preeclampsia is a common (approximately 7% of all pregnancies) disorder of pregnancy in which the normal hemodynamic response to pregnancy is compromised. Despite many years of intensive research, the pathogenesis of preeclampsia is still not fully understood. The objective of the present study was to investigate the levels of coenzyme Q(10) (CoQ(10)) in placental tissue compared to maternal and umbilical cord levels both during normal pregnancy and in those complicated with preeclampsia. Pregnant women (n = 30) and women with preeclampsia (n = 30) were included. Maternal, newborn cord blood levels and placental content of coenzyme Q(10) were measured by high performance liquid chromatography (HPLC). Plasma coenzyme Q(10) levels were significantly higher in normal pregnant women than in women with preeclampsia. CoQ(10) content in placenta from women with preeclampsia (mean 0.28 SEM 0.11 nmol/mg protein) was significantly higher compared to normal pregnancy (mean 0.09 SEM 0.01 nmol/mg protein; p = 0.05). Levels of CoQ(10) in cord blood from normal pregnant women (mean 0.30 SEM 0.05 micromol/l) were significantly lower than in preeclamptic women (mean 4.03 SEM 2.38 micromol/l). In conclusion, these data indicate a possible involvement of CoQ(10) in preeclampsia that might bear deep physiopathological significance and deserve to be further elucidated.     

PEDF蛋白在子痫前期患者胎盘上的表达及意义

目的:研究子痫前期患者胎盘组织中色素上皮衍生因子(pigment epithelium-derived factor,PEDF)的表达,探讨PEDF在子痫前期发病中的作用。方法:选取2012年3月至2013年3月在我院产科住院剖宫产的20例子痫前期孕妇作为研究对象,另选取同期正常分娩的孕妇20例作为对照组。采用Western blot、免疫荧光组织化学方法检测子痫前期患者和正常对照组妇女胎盘组织中PEDF和血管内皮生长因子(vascular endothelial growth factor,VEGF)的表达,并通过免疫荧光方法计数胎盘微血管密度(MVD)。结果:同正常对照组相比,子痫前期患者胎盘组织中PEDF表达升高,而VEGF表达则减少。PEDF与VEGF组织表达位置大致相同。子痫前期患者胎盘组织中PEDF表达与24h尿蛋白定量呈正相关,与VEGF表达及MVD计数呈负相关;VEGF表达与MVD计数呈正相关。结论:PEDF与子痫前期疾病发生发展及病情轻重程度有关;PEDF可能是通过影响胎盘血管的重铸,而参与子痫前期疾病的发生发展。     

Role of Prostate Apoptosis Response 4 in Translocation of GRP78 from the Endoplasmic Reticulum to the Cell Surface of Trophoblastic Cells

Glucose-regulated protein 78 (GRP78) is an endoplasmic reticulum (ER) molecular chaperone that belongs to the heat shock protein 70 family. GRP78 is also present on the cell surface membrane of trophoblastic cells, where it is associated with invasive or fusion properties of these cells. Impaired mechanism of GRP78 relocation from ER to the cell surface was observed in preeclamptic cytotrophoblastic cells (CTB) and could take part in the pathogenesis of preeclampsia. In this study, we have investigated whether prostate apoptosis response 4 (Par-4), a protein identified as a partner of GRP78 relocation to the cell surface in prostate cancer cells, is present in trophoblastic cells and is involved in the translocation of GRP78 to the cell surface of CTB. Par-4 is indeed present in trophoblastic cells and its expression correlates with expression of membrane GRP78. Moreover, overexpression of Par-4 led to an increase of cell surface expression of GRP78 and decreased Par-4 gene expression reduced cell surface localization of GRP78 confirming a role of Par-4 in relocation of GRP78 from ER to the cell surface. Accordingly, invasive property was modified in these cells. In conclusion, we show that Par-4 is expressed in trophoblastic cells and is involved in transport of GRP78 to the cell surface and thus regulates invasive property of extravillous CTB.     

MUC1 expression is increased during human placental development and suppresses trophoblast-like cell invasion in vitro

Mucin (MUC)1 is a multifunctional mucin expressed by a variety of reproductive tract epithelia. Trophoblast invasion is essential for normal placental development. However, MUC1 expression in the human placenta throughout pregnancy and the role of MUC1 in trophoblast-like cell invasion are still unclear. In the present study, results from quantitative RT-PCR and Western blot demonstrated that MUC1 mRNA and MUC1 protein expression, respectively, increased with gestational age of the human placenta. Immunohistochemistry revealed that MUC1 in placental villi was mainly expressed by syncytiotrophoblasts throughout pregnancy and increased with gestational age. Interestingly, we found two populations of extravillous trophoblasts, MUC1-positive and MUC1-negative cells, in decidua. The numbers of MUC1-positive extravillous trophoblasts were increased during placental development. Furthermore, MUC1 overexpression significantly (P < 0.01) suppressed matrigel invasion of trophoblast-like JAR cells by 34.6% +/- 4.5% compared with control, which was associated with a decrease in MMP9 activity assessed by gelatin zymography. Our results suggest that MUC1 expression in the human placenta is increased during placental development, and its overexpression suppresses trophoblast-like cell invasion in vitro.     

Aberrantly Up-regulated miR-20a in Pre-eclampsic Placenta Compromised the Proliferative and Invasive Behaviors of Trophoblast Cells by Targeting Forkhead Box Protein A1

Preeclampsia is a serious complication in pregnancy. Dysregulation of trophoblast cell proliferation and invasion is a major pathological alteration observed in preeclampsia. Recently, microRNAs were shown to participate in the pathogenesis of preeclampsia. In this study we explored the effect of miR-20a on the proliferation and invasion of trophoblast cells and the underlying mechanism.We verified the distribution of miR-20a in human placenta by in situ hybridization. Real time PCR data showed that the level of miR-20a increased by 2.6 folds in human preeclampsia than normal tissues. We then cultured trophoblast-like JEG-3 cells and evaluated the effect of miR-20a on JEG-3 cell proliferation, migration and invasion. Overexpression of miR-20a significantly inhibited the proliferation, migration and invasion of cultured JEG-3 cells, which were abolished by co-transfection of AMO-20a. Transfection of miR-20a also inhibited JEG-3 cell xenograft tumor growth in nude mice. Luciferase assay technique was used to identify the direct regulation of miR-20a on Forkhead Box Protein A1(FOXA1). Transfection of miR-20a markedly reduced the luciferase activity of the chimeric plasmid containing the 3''UTR of FOXA1, indicating FOXA1 is the target of miR-20a. Furthermore, transfection of miR-20a inhibited both protein and mRNA expression of FOXA1 in JEG-3 cells. In summary, the upregulated miR-20a in human preeclampsia tissue can inhibit the proliferative and invasive activities of trophoblast cells by repressing the expression of FOXA1.