Advanced oxidation protein products enhances soluble Fms-like tyrosine kinase 1 expression in trophoblasts: a possible link between oxidative stress and preeclampsia.

Accumulation of advanced oxidation protein products (AOPPs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome. Alterations in the regulation and signaling of angiogenic pathways have been recognized as a link between these conditions and pre-eclampsia. To investigate the possible impact of AOPPs on soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in trophoblasts. A trophoblast cell line (HRT-8/SVneo) was treated with various concentrations of AOPPs. The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts were measured with the use of real-time polymerase chain reaction; and the secretion of sFlt-1, VEGF, and PlGF protein from trophoblasts were detected with the use of ELISA. Exposure of HRT-8/SVneo cells to AOPPs induced overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner. These effects could be inhibited by apocynin, an inhibitors of NADPH oxidase. Our data identified AOPPs as a class of important mediator in the regulation and signaling of angiogenic pathways of trophoblasts. Accumulation of AOPPs might contributes to the pathogenesis of preeclampsia by promoting sFlt-1 production in trophoblasts.

Huang QT ，Wang SS ，Zhang M ，Huang LP ，Tian JW ，Yu YH ，Wang ZJ ，Zhong M ... -  《-》

Advanced glycation end products as an upstream molecule triggers ROS-induced sFlt-1 production in extravillous trophoblasts: a novel bridge between oxidative stress and preeclampsia.

Although abnormal soluble fms-like tyrosine kinase-1 (sFlt-1) production is thought to be an important factor in the pathogenesis of pre-eclampsia, the mechanisms that regulate the production of sFlt-1 during pre-eclampsia are unclear. Accumulation of advanced glycation end products (AGEs) is prevalent in obesity, advanced maternal age, diabetes mellitus, and polycystic ovary syndrome. Alterations in the regulation and signaling of angiogenic pathways have been considered as a link between these conditions and pre-eclampsia. The purpose of this study was to explore the possible effects of AGEs on sFlt-1 secretion in extravillous trophoblasts (EVT). A EVT cell line (HRT-8/SVneo) was treated with various concentrations of AGEs-BSA. The mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in EVT were detected with real-time polymerase chain reaction. The secretion of sFlt-1, VEGF, and PlGF protein from EVT was measured with ELISA. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to AGEs-BSA induced increased intracellular ROS generation and overexpression of sFlt-1 at mRNA and protein levels in a dose dependent manner. Anti-RAGE immunoglobulin G or apocynin (an inhibitors of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our data suggested that AGEs may be a new class of important mediator in the regulation of angiogenic pathways of EVT. Accumulation of AGEs might contribute to the pathogenesis of preeclampsia by promoting sFlt-1 production through activation of RAGE/NADPH oxidase dependent pathway in EVT.

Huang QT ，Zhang M ，Zhong M ，Yu YH ，Liang WZ ，Hang LL ，Gao YF ，Huang LP ，Wang ZJ ... -  《-》

Edaravone inhibits hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 expression: a possible therapeutic approach to preeclampsia.

To investigate the effects of edaravone, a potent free radical scavenger used clinically, on hypoxia-induced trophoblast-soluble Fms-like tyrosine kinase 1 (sFlt-1) expression. A trophoblast cell line (HRT-8/SVneo) impaired by cobalt chloride (CoCl2) was used as the cell model under hypoxic conditions. 3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyl tetrazolium bromide (MTT) was used to measure the viability of cells exposed to CoCl2 and edaravone. The levels of intracellular reactive oxygen species (ROS) were analyzed by flow cytometry. mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts was measured by real-time polymerase chain reaction, and the secretion of sFlt-1, VEGF, and PlGF proteins was analyzed by enzyme-linked immunosorbent assays (ELISAs). A human umbilical vein endothelial cell (HUVEC) tube-formation assay was performed to identify the effects of CoCl2 and edaravone on vascular development. CoCl2 treatment caused the loss of trophoblast viability, the formation of ROS, and sFlt-1 mRNA and protein expression in a dose-dependent manner. Pretreatment with edaravone significantly inhibited hypoxia-induced oxidative stress formation and sFlt-1 expression in trophoblasts. Neither PlGF nor VEGF mRNA or protein expression was increased by CoCl2. In the in vitro tube formation assay, edaravone showed a protective role in vascular development under hypoxic conditions. This study demonstrated that hypoxia leading to increased sFlt-1 release in trophoblasts may contribute to the placental vascular formation abnormalities observed in preeclampsia and suggested that the free radical scavenger edaravone could be a candidate for the effective treatment of preeclampsia.

Zhao Y ，Zheng YF ，Luo QQ ，Yan T ，Liu XX ，Han L ，Zou L ... -  《-》

Thrombin enhances soluble Fms-like tyrosine kinase 1 expression in trophoblasts; possible involvement in the pathogenesis of preeclampsia.

To investigate the possible impact of thrombin on soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in trophoblasts. Experimental. University hospital laboratory. A trophoblast cell line (HRT-8/SVneo) was treated with thrombin, protease-activated receptor 1 (PAR-1)-specific agonist SFLLERN, and thrombin antagonist PPACK. mRNA expression of sFlt-1, vascular endothelial growth factor (VEGF), and placental growth factor (PlGF) in trophoblasts, with the use of real-time polymerase chain reaction; and the secretion of sFlt-1, VEGF, and PlGF protein from trophoblasts, with the use of ELISA. Administration of thrombin (10 U/mL) and PAR-1-specific agonist SFLLRN (300 μmol/L) increased sFlt-1 mRNA expression (4.24 ± 0.74- and 4.21 ± 0.79-fold, respectively) and protein secretion (5.08 ± 0.42- and 1.89 ± 0.16-fold, respectively) in HRT-8/SVneo. The induction of sFlt-1 protein secretion by thrombin was dose dependent. The effect of thrombin was completely reduced by thrombin inhibitor PPACK. Thrombin increased mRNA expression of VEGF but did not change VEGF secretion and PlGF mRNA expression and secretion. During placental development, thrombin, generated in the local hemorrhage of the uteroplacenta increases trophoblast expression of sFlt-1. Consequently, thrombin may contribute to the pathogenesis of preeclampsia.

Zhao Y ，Koga K ，Osuga Y ，Nagai M ，Izumi G ，Takamura M ，Harada M ，Hirota Y ，Yoshino O ，Taketani Y ... -  《-》

Activation of PAR-1/NADPH oxidase/ROS signaling pathways is crucial for the thrombin-induced sFlt-1 production in extravillous trophoblasts: possible involvement in the pathogenesis of preeclampsia.

Preeclampsia was characterized by excessive thrombin generation in placentas and previous researches showed that thrombin could enhance soluble Fms-like tyrosine kinase 1 (sFlt-1) expression in first trimester trophoblasts. However, the detailed mechanism for the sFlt-1 over-production induced by thrombin was largely unknown. The purpose of this study was to explore the possible signaling pathway of thrombin-induced sFlt-1 production in extravillous trophoblasts (EVT). An EVT cell line (HRT-8/SVneo) was treated with various concentrations of thrombin. The mRNA expression and protein secretion of sFlt-1 in EVT were detected with real-time polymerase chain reaction and ELISA, respectively. The levels of intracellular reactive oxygen species (ROS) production were determined by DCFH-DA. Exposure of EVT to thrombin induced increased intracellular ROS generation and overexpression of sFlt-1 at both mRNA and protein levels in a dose dependent manner. Short interfering RNA (siRNA) directed against PAR-1 or apocynin (an inhibitor of NADPH oxidase) could decrease the intracellular ROS generation and subsequently suppressed the production of sFlt-1 at mRNA and protein levels. Our results suggested that thrombin increased sFlt-1 production in EVT via the PAR-1 /NADPH oxidase /ROS signaling pathway. This also highlights the PAR-1 / NADPH oxidase / ROS pathway might be a potential therapeutic target for the prevention of preeclampsia in the future.

Huang QT ，Chen JH ，Hang LL ，Liu SS ，Zhong M ... -  《-》