lntracellular redox homeostasis plays a critical role in determining tumor cells＇ sensitivity to drug-induced apoptosis. Here we investigated the role of thioredoxin-1 （TRX1）, a key component of redox regulation, i...lntracellular redox homeostasis plays a critical role in determining tumor cells＇ sensitivity to drug-induced apoptosis. Here we investigated the role of thioredoxin-1 （TRX1）, a key component of redox regulation, in arsenic trioxide （AS2O3）-induced apoptosis. Over-expression of wild-type TRX1 in HepG2 cells led to the inhibition of As2O3-induced cytochrome c （cyto c） release, caspase activation and apoptosis, and down-regulation of TRX1 expression by RNAi sensitized HepG2 cells to As2O3-induced apoptosis. Interestingly, mutation of the active site of TRX1 from Cys^32/35 to Ser^32/35 converted this molecule from an apoptotic protector to an apoptotic promoter. In an effort to understand the mechanisms of this conversion, we used isolated mitochondria from mouse liver and found that recombinant wild-type TRX1 could protect mitochondria from the apoptotic changes. In contrast, the mutant form of TRX1 alone elicited mitochondria-related apoptotic changes, including the mitochondrial permeability transition pore （mPTP） opening, loss of mitochondrial membrane potential, and cyto c release from mitochondria. These apoptotic effects were inhibited by cyclosporine A （CsA）, indicating that mutant TRX1 targeted to mPTP. Alteration of TRX1 from its reduced form to oxidized form in vivo by 2,4-dinitrochlorobenzene （DNCB）, a specific inhibitor ofTRX reductase, also sensitized HepG2 cells to As203-induced apoptosis. These data suggest that TRX1 plays a central role in regulating apoptosis by blocking cyto c release, and inactivation of TRX1 by either mutation or oxidization of the active site cysteines may sensitize tumor cells to As2O3-induced apoptosis.展开更多
Objective:Alzheimer’s disease( AD) is the most common neurodegenerative disorder which is characterized by amyloid-β( Aβ) aggradation in the brain and impairment of cognitive function. Thioredoxin-1( Trx-1) is a re...Objective:Alzheimer’s disease( AD) is the most common neurodegenerative disorder which is characterized by amyloid-β( Aβ) aggradation in the brain and impairment of cognitive function. Thioredoxin-1( Trx-1) is a redox regulating protein,and plays roles in resisting the oxidative stress and protecting neurons. Our previous study found that Trx-1 improved the cognitive function of Parkinson’s Disease( PD) mice. Geranylgeranylacetone( GGA) is an antiulcer drug and induces the expression of Trx-1 in vivo and in vitro. However,whether Trx-1 improves cognitive functions in mice of APP/PS1 or GGA protects SH-SY5 Y cells from cytotoxicity induced by Aβ is still unknown. The objective of present is to investigate the roles of Trx-1 and GGA in inhibiting neurotoxicity of Aβ. Methods:We used MTT assay to test the cell viability induced by Aβ(25-35) and western blot to detect the expression of Trx-1 in SH-SY5 Y cells. Trx-1 overexpression transgenic mice were hybridized with APP/PS1 transgenic mice to get control,Trx-1,Tx-1/APP/PS1 and APP/PS1 mice. Then we used Morris water maze,high plus maze and object recognition test to detect the cognitive function of different kinds of mice. We also used RT-PCR and western blot to test the mRNA level and expression of Trx-1,APP,PS1 and Aβ. Results:In our present study,we demonstrated that Aβ(25-35) decreased the cell viability and the expression of Trx-1 in SH-SY5 Y cells. The cell viability and the expression of Trx-1 were reversed by GGA. Our results showed that the escape latency in APP/PS1 mice was longer when compared with the Trx-1/APP/PS1 mice in Morris water maze and high plus maze. Whereas navigational experiments in Morris water maze result showed that the total number of crossings and the percentage of time spent in the target quadrant were significantly decreased in APP/PS1 mice when compared to Trx-1/APP/PS1 mice. Object recognition test the discrimination index was significantly decreased in APP/PS1 mice when compared with Trx-1/APP/PS1 mice. The mRNA levels and the expression of APP,PS1 and Aβ were decreased in Trx-1/APP/PS1 mice when compared to APP/PS1 mice. Conclusion:These results suggest that GGA protects SH-SY5 Y cells from cytotoxicity induced by Aβ(25-35) and restored the expression of Trx-1. Trx-1 overexpression improves cognitive function of APP/PS1 mice. Trx-1 may be a potential therapeutic target for the clinical management of AD.展开更多
背景:程序性细胞死亡受体1(programmed death receptor-1,PD-1)在高糖环境下影响骨髓间充质干细胞成骨分化的作用机制尚不清楚。目的:探讨高糖环境中PD-1对大鼠骨髓间充质干细胞成骨分化的影响及其调控机制。方法:将大鼠骨髓间充质干细...背景:程序性细胞死亡受体1(programmed death receptor-1,PD-1)在高糖环境下影响骨髓间充质干细胞成骨分化的作用机制尚不清楚。目的:探讨高糖环境中PD-1对大鼠骨髓间充质干细胞成骨分化的影响及其调控机制。方法:将大鼠骨髓间充质干细胞随机分为正常糖组(5.6 mmol/L)、高糖组(30 mmol/L)、PD-1过表达组、PD-1过表达空载组、PD-1敲低组、PD-1敲低空载组、PI3K/AKT通路抑制剂组(PD-1敲低+5μmol/L LY294002)。通过在高糖培养基中培养大鼠骨髓间充质干细胞来模拟体外糖尿病环境,采用qRT-PCR检测大鼠骨髓间充质干细胞中PD-1及其配体PD-L1和成骨标志物Runx2、OSX的mRNA表达,采用碱性磷酸酶染色和茜素红S染色观察成骨分化能力,采用CCK-8检测细胞增殖情况,采用Western blot检测PD-1、PD-L1、p-PI3K、p-AKT的蛋白表达。结果与结论:①高糖组PD-1及PD-L1表达显著高于正常糖组,高糖组骨髓间充质干细胞的成骨分化能力较正常糖组显著下降;②敲低PD-1表达可以促进骨髓间充质干细胞的成骨分化、增加细胞增殖活性,同时激活PI3K/AKT通路;③加入PI3K/AKT通路抑制剂LY294002后,骨髓间充质干细胞成骨分化能力显著下降。结果表明:PD-1依赖于PI3K/AKT信号通路抑制高糖环境下大鼠骨髓间充质干细胞的成骨分化。展开更多
文摘lntracellular redox homeostasis plays a critical role in determining tumor cells＇ sensitivity to drug-induced apoptosis. Here we investigated the role of thioredoxin-1 （TRX1）, a key component of redox regulation, in arsenic trioxide （AS2O3）-induced apoptosis. Over-expression of wild-type TRX1 in HepG2 cells led to the inhibition of As2O3-induced cytochrome c （cyto c） release, caspase activation and apoptosis, and down-regulation of TRX1 expression by RNAi sensitized HepG2 cells to As2O3-induced apoptosis. Interestingly, mutation of the active site of TRX1 from Cys^32/35 to Ser^32/35 converted this molecule from an apoptotic protector to an apoptotic promoter. In an effort to understand the mechanisms of this conversion, we used isolated mitochondria from mouse liver and found that recombinant wild-type TRX1 could protect mitochondria from the apoptotic changes. In contrast, the mutant form of TRX1 alone elicited mitochondria-related apoptotic changes, including the mitochondrial permeability transition pore （mPTP） opening, loss of mitochondrial membrane potential, and cyto c release from mitochondria. These apoptotic effects were inhibited by cyclosporine A （CsA）, indicating that mutant TRX1 targeted to mPTP. Alteration of TRX1 from its reduced form to oxidized form in vivo by 2,4-dinitrochlorobenzene （DNCB）, a specific inhibitor ofTRX reductase, also sensitized HepG2 cells to As203-induced apoptosis. These data suggest that TRX1 plays a central role in regulating apoptosis by blocking cyto c release, and inactivation of TRX1 by either mutation or oxidization of the active site cysteines may sensitize tumor cells to As2O3-induced apoptosis.
文摘Objective:Alzheimer’s disease( AD) is the most common neurodegenerative disorder which is characterized by amyloid-β( Aβ) aggradation in the brain and impairment of cognitive function. Thioredoxin-1( Trx-1) is a redox regulating protein,and plays roles in resisting the oxidative stress and protecting neurons. Our previous study found that Trx-1 improved the cognitive function of Parkinson’s Disease( PD) mice. Geranylgeranylacetone( GGA) is an antiulcer drug and induces the expression of Trx-1 in vivo and in vitro. However,whether Trx-1 improves cognitive functions in mice of APP/PS1 or GGA protects SH-SY5 Y cells from cytotoxicity induced by Aβ is still unknown. The objective of present is to investigate the roles of Trx-1 and GGA in inhibiting neurotoxicity of Aβ. Methods:We used MTT assay to test the cell viability induced by Aβ(25-35) and western blot to detect the expression of Trx-1 in SH-SY5 Y cells. Trx-1 overexpression transgenic mice were hybridized with APP/PS1 transgenic mice to get control,Trx-1,Tx-1/APP/PS1 and APP/PS1 mice. Then we used Morris water maze,high plus maze and object recognition test to detect the cognitive function of different kinds of mice. We also used RT-PCR and western blot to test the mRNA level and expression of Trx-1,APP,PS1 and Aβ. Results:In our present study,we demonstrated that Aβ(25-35) decreased the cell viability and the expression of Trx-1 in SH-SY5 Y cells. The cell viability and the expression of Trx-1 were reversed by GGA. Our results showed that the escape latency in APP/PS1 mice was longer when compared with the Trx-1/APP/PS1 mice in Morris water maze and high plus maze. Whereas navigational experiments in Morris water maze result showed that the total number of crossings and the percentage of time spent in the target quadrant were significantly decreased in APP/PS1 mice when compared to Trx-1/APP/PS1 mice. Object recognition test the discrimination index was significantly decreased in APP/PS1 mice when compared with Trx-1/APP/PS1 mice. The mRNA levels and the expression of APP,PS1 and Aβ were decreased in Trx-1/APP/PS1 mice when compared to APP/PS1 mice. Conclusion:These results suggest that GGA protects SH-SY5 Y cells from cytotoxicity induced by Aβ(25-35) and restored the expression of Trx-1. Trx-1 overexpression improves cognitive function of APP/PS1 mice. Trx-1 may be a potential therapeutic target for the clinical management of AD.
