Xinwei Shi

Effect of epigenetic modification of maspin on extravillous trophoblastic function.

SummaryThis study investigated the effect of epigenetic modification of maspin on extravillous trophoblastic function. The mRNA expression of maspin in placentae from normotensive and preeclamptic pregnant women was detected by RT-PCR. TEV-1 cells, a human first-trimester extravillous trophoblast cell line, were cultured and treated with CoCl2 (300 μmol/L) to induce chemical hypoxia and with 5-aza (500 nmol/L) to induce demethylation. The mRNA expression of maspin in TEV-1 cells subjected to different treatments was determined by RT-PCR, and the proliferative and migratory abilities of TEV-1 cells were assessed by cell counting kit-8 (CCK-8) and Transwell assays. Our results showed that the maspin mRNA expression level in placentae from preeclamptic women was much higher than that from normotensive women. CoCl2 or 5-aza could up-regulate the mRNA expression of maspin and significantly suppress the proliferation and migration of TEV-1 cells. It was concluded that the epigenetic modification in promoter region of maspin contributes to incomplete trophoblast invasion, which offers a novel approach for predicting and treating placental dysfunction.This study investigated the effect of epigenetic modification of maspin on extravillous trophoblastic function. The mRNA expression of maspin in placentae from normotensive and preeclamptic pregnant women was detected by RT-PCR. TEV-1 cells, a human first-trimester extravillous trophoblast cell line, were cultured and treated with CoCl2 (300 μmol/L) to induce chemical hypoxia and with 5-aza (500 nmol/L) to induce demethylation. The mRNA expression of maspin in TEV-1 cells subjected to different treatments was determined by RT-PCR, and the proliferative and migratory abilities of TEV-1 cells were assessed by cell counting kit-8 (CCK-8) and Transwell assays. Our results showed that the maspin mRNA expression level in placentae from preeclamptic women was much higher than that from normotensive women. CoCl2 or 5-aza could up-regulate the mRNA expression of maspin and significantly suppress the proliferation and migration of TEV-1 cells. It was concluded that the epigenetic modification in promoter region of maspin contributes to incomplete trophoblast invasion, which offers a novel approach for predicting and treating placental dysfunction.

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

OBJECTIVE Preeclampsia 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. METHODS We 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. RESULTS Maspin 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. DISCUSSION Hypomethylation 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.

Promoter Hypomethylation of Maspin Inhibits Migration and Invasion of Extravillous Trophoblast Cells during Placentation

Objective Extravillous trophoblast (EVT) cells invade the endometrium and the maternal spiral arterioles during the first trimester. Mammary Serine Protease Inhibitor (Maspin, SERPINB5) plays a putative role in regulating the invasive activity of cytotrophoblasts. The maspin gene is silenced in various cancers by an epigenetic mechanism that involves aberrant cytosine methylation. We investigated the effect of the methylation status of the maspin promoter on the maspin expression and the aggressiveness of EVT cells. Methods Western blotting was used to detect the maspin protein expression in EVT cells upon hypoxia. The proliferative ability, the apoptosis rate and the migration and invasiveness were measured with Cell Counting Kit-8 assay, Flow Cytometry technology and Transwell methods. Subsequently, we treated cells with recombinant maspin protein. The methylation degree of maspin promoter region upon hypoxia/ decitabine was detected by bisulfite sequencing PCR and methylation-specific PCR. Finally, we explored the effects of decitabine on maspin protein expression and the aggressiveness of EVT cells. Results Hypoxia effectively increased maspin protein expression in EVT cells and significantly inhibited their aggressiveness. The addition of recombinant maspin protein inhibited this aggressiveness. Decitabine reduced the methylation in the maspin promoter region and effectively increased the maspin protein expression, which significantly weakened the migration and invasiveness of EVT cells. Discussion The methylation status of the maspin promoter is an important factor that affects the migration and invasion of EVT cells during early pregnancy. A decrease in the methylation status can inhibit the migration and invasion of EVT cells to affect placentation and can result in the ischemia and hypoxia of placenta.

Low molecular weight heparin improves proteinuria in rats with L-NAME induced preeclampsia by decreasing the expression of nephrin, but not podocin

Objective: We investigated the relationship between proteinuria in L-NAME induced preeclampsia and the expression of nephrin and podocin, and the effect of low-molecular-weight-heparin (LMWH) on proteinuria in rats. Methods: We detected nephrin and podocin expression of kidneys of pregnant rats after L-NAME and after LMWH intervening pregnant rats. Results: Glomerular nephrin expression in L-NAME induced preeclampsia significantly decreased, but not podocin. Nephrin was relatively increased after LMWH intervention and this was accompanied by a decrease in proteinuria. Conclusion: We demonstrate that down-regulation of nephrin is involved in L-NAME induced proteinuria, and that LMWH reduces proteinuria by up-regulation of neprhin.

Decitabine Improves the Clinical Manifestations of Rats With l-NAME-Induced Pre-eclampsia: A Potential Approach to Studying Pre-eclampsia

Objective: Pre-eclampsia is a major cause of maternal mortality and morbidity. Conditions with low oxygen tension are regarded as a key factor. Decitabine can partly attenuate the effects of hypoxia. This research was designed to investigate the effects of decitabine in rats with NG-Nitro-L-arginine Methyl Eater (L-NAME) induced pre-eclampsia and to explore the molecular mechanisms. Methods: A Wistar rat model of pre-eclampsia was established by intraperitoneal injection of L-NAME, and the intervention reagent was decitabine. Blood pressure (BP) and 24-h urinary protein were monitored. The expression of Mammary Serine Protease Inhibitor (SERPINB5, maspin) in the placenta was detected by reverse transcriptase-polymerase chain reaction (RT-PCR) and western blotting. Results: Systolic BP in the tail artery of pregnant rats was increased by more than 30 mm Hg, and 24-h urinary protein was significantly increased after L-NAME was added. After decitabine treatment, blood pressure and 24-h urinary protein were significantly decreased. The expression of SERPINB5 in the placenta significantly increased after L-NAME was added. Decitabine significantly elevated the expression of SERPINB5 in the placenta of rats with L-NAME-induced preeclampsia. Conclusion: Decitabine reduced 24-h urinary protein and partly decreased blood pressure of pre-eclampsia in late pregnancy in rats with L-NAME-induced pre-eclampsia and increased the expression of SERPINB5, but the molecular mechanism of decitabines effect remains unknown. This research provided a potential approach to studying the pathogenesis, treatment and prevention of pre-eclampsia.

Low molecular weight heparin decreases the permeability of glomerular endothelial cells when exposed to pre-eclampsia serum in vitro.

Low molecular weight heparin (LMWH) has been used to treat certain kidney diseases such as pre‐eclampsia, in which extensive levels of proteinuria are associated with dysfunction of glomerular endothelium. In our study, we investigated whether LMWH could affect the permeability of and ET‐1 expression in human glomerular endothelial cells (GEnC) incubated with pre‐eclampsia serum.

Effects of maternal serum on permeability of glomerular endothelial cell membrane

SummaryThe mechanism of injury on the human glomerular endothelial cells (ciGENC) induced by preeclampsia serum was investigated. Concentration of maternal serum sFlt-1 protein was detected by ELISA. Fluorescently-labeled bovine serum albumin infiltrating through lower chamber of Transwell was measured by multifunction microplate reader. Morphologic change of ciGENC was observed under inverted phase contrast microscope. The concentration of sflt-1 in preeclampsia groups was significantly increased as compared with control group (P<0.01). Permeability in preeclampsia groups was significantly increased as compared with control group (P<0.01). By contrast with severe preeclampsia group, the permeability of ciGENC monolayer in mild preeclampsia group was decreased significantly (P<0.05). Intervention of exogenous VEGF significantly decreased permeability of ciGENC in preeclampsia groups. It was concluded that sFlt-1 increased ciGENC permeability by damaging integrity of endothelial barrier function.The mechanism of injury on the human glomerular endothelial cells (ciGENC) induced by preeclampsia serum was investigated. Concentration of maternal serum sFlt-1 protein was detected by ELISA. Fluorescently-labeled bovine serum albumin infiltrating through lower chamber of Transwell was measured by multifunction microplate reader. Morphologic change of ciGENC was observed under inverted phase contrast microscope. The concentration of sflt-1 in preeclampsia groups was significantly increased as compared with control group (P<0.01). Permeability in preeclampsia groups was significantly increased as compared with control group (P<0.01). By contrast with severe preeclampsia group, the permeability of ciGENC monolayer in mild preeclampsia group was decreased significantly (P<0.05). Intervention of exogenous VEGF significantly decreased permeability of ciGENC in preeclampsia groups. It was concluded that sFlt-1 increased ciGENC permeability by damaging integrity of endothelial barrier function.

Maspin impairs the function of endothelial cells: an implying pathway of preeclampsia

BackgroudWidespread endothelial injury contributes to the occurrence of preeclampsia. Maspin, first identified as a tumor suppressor, plays a critical role in cell invasion and angiogenesis. Our previous studies found that the expression of maspin was increased in preeclampsic placenta. In this research, we studied the function of human umbilical vein endothelial cells (HUVECs) to explore the role and possible mechanism of maspin gene in the pathogenesis of preeclampsia.MethodsHUVECs were treated with different concentration of recombinant human maspin protein (r-maspin) during normoxia and hypoxia, we detected the proliferation, apoptosis, migration and tube formation of HUVECs. We also assessed nitride oxide (NO) synthesis and the expression of matrix metalloproteinase 2 (MMP2) to further explore the underlying molecular mechanism.ResultsThere was only slight maspin expression at mRNA level in HUVECs. Treated HUVECs with r-maspin, the proliferation of HUVECs was significantly promoted both under normoxia and hypoxia. The tubes formed by HUVECs were significantly inhibited and NO synthesis was significantly reduced by r-maspin. Meantime, r-maspin also inhibited MMP2 expression and activity in HUVECs. However, there was no significant change in the migration and apoptosis of HUVECs.ConclusionsMaspin may be an important participant for mediating endothelial function and ultimately leads to the occurence of preeclamsia.

Upregulation of sFlt-1 by trophoblasts induces the barrier dysfunction of glomerular endothelial cells

SummaryThis study examined the effect of over-expression of sFlt-1 by trophoblasts on the barrier function of glomerular endothelial cells and the role of VEGF in this process in order to explore the pathogenesis of glomerular disease in preeclampsia. SFlt-1 expression in the human trophoblasts (TEV-1 cells) was enhanced by transfecting sFlt-1 plasmid DNA into TEV-1 cells. The monolayer barrier function of glomerular endothelial cells (ciGEnCs) was determined by measuring the fluorescence intensity of bovine serum albumin (BSA) that crossed the monolayer of glomerular endothelial cells. The results showed that the over-expression of sFlt-1 by TEV-1 cells led to the barrier dysfunction of ciGEnCs, and the exogenous VEGF could alleviate the ciGEnCs dysfunction resulting from the over-expression of sFlt-1 to a certain extent. It was concluded that the dysregulation of sFlt-1 and VEGF in preeclamptic pregnancy may contribute to the barrier dysfunction of glomerular endothelial cells, and VEGF may play an important role in maintaining the barrier function of glomerular endothelial cells, but it may not be the sole factor.This study examined the effect of over-expression of sFlt-1 by trophoblasts on the barrier function of glomerular endothelial cells and the role of VEGF in this process in order to explore the pathogenesis of glomerular disease in preeclampsia. SFlt-1 expression in the human trophoblasts (TEV-1 cells) was enhanced by transfecting sFlt-1 plasmid DNA into TEV-1 cells. The monolayer barrier function of glomerular endothelial cells (ciGEnCs) was determined by measuring the fluorescence intensity of bovine serum albumin (BSA) that crossed the monolayer of glomerular endothelial cells. The results showed that the over-expression of sFlt-1 by TEV-1 cells led to the barrier dysfunction of ciGEnCs, and the exogenous VEGF could alleviate the ciGEnCs dysfunction resulting from the over-expression of sFlt-1 to a certain extent. It was concluded that the dysregulation of sFlt-1 and VEGF in preeclamptic pregnancy may contribute to the barrier dysfunction of glomerular endothelial cells, and VEGF may play an important role in maintaining the barrier function of glomerular endothelial cells, but it may not be the sole factor.

Hypoxia downregulates the angiogenesis in human placenta via Notch1 signaling pathway

SummaryPlacentation, which is critical for maternal-fetal exchange of nutrients and gases, is a complicated process comprising stepwise vasculogenesis and angiogenesis. Hypoxia caused by impaired trophoblast invasion may cause various angiogenic abnormalities in human placenta. The Notch1 signaling pathway plays an important role in the regulation of angiogenesis. The angiogenesis of human umbilical vein endothelial cells (HUVECs) under normal/hypoxic conditions and the mRNA/protein level of Notch1/Dell4/Jagged1 were investigated in this study. The effects of DAPT/JAG-1 on the migration of HUVECs were also assessed by cell wound healing assay, so as to discover the possible role of notch1 signaling pathway in the angiogenesis of human placenta. The results showed that angiogenic ability of HUVECs was seriously reduced under hypoxic conditions. The mRNA and protein levels of Notch1/Dell4/Jagged1 were decreased in the hypoxic group compared to the control one. In addition, the migration capability of HUVECs was significantly obstructed when treated with DAPT and under hopoxic condition, but promoted when treated with JAG-1. The above results demonstrate that hypoxia downregulates the angiogenesis in human placenta via Notch1 signaling pathway.Placentation, which is critical for maternal-fetal exchange of nutrients and gases, is a complicated process comprising stepwise vasculogenesis and angiogenesis. Hypoxia caused by impaired trophoblast invasion may cause various angiogenic abnormalities in human placenta. The Notch1 signaling pathway plays an important role in the regulation of angiogenesis. The angiogenesis of human umbilical vein endothelial cells (HUVECs) under normal/hypoxic conditions and the mRNA/protein level of Notch1/Dell4/Jagged1 were investigated in this study. The effects of DAPT/JAG-1 on the migration of HUVECs were also assessed by cell wound healing assay, so as to discover the possible role of notch1 signaling pathway in the angiogenesis of human placenta. The results showed that angiogenic ability of HUVECs was seriously reduced under hypoxic conditions. The mRNA and protein levels of Notch1/Dell4/Jagged1 were decreased in the hypoxic group compared to the control one. In addition, the migration capability of HUVECs was significantly obstructed when treated with DAPT and under hopoxic condition, but promoted when treated with JAG-1. The above results demonstrate that hypoxia downregulates the angiogenesis in human placenta via Notch1 signaling pathway.