Protection of Oxidant Toxicity by Glutathione S Transferases

谷胱甘肽 S 转移酶对氧化剂毒性的保护

基本信息

批准号：
7337306
负责人：
YOGESH Chandra AWASTHI
金额：
$ 25.45万
依托单位：
UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-12-15 至 2009-09-20
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7337306
关键词：
4 hydroxynonenal Acrolein Antibodies Antioxidants Apoptosis Apoptotic Attenuated Biological Biological Assay CYP2E1 gene Cell Line Cells Chronic Class Condition DNA DNA Binding DNA Damage Degenerative Disorder Doxorubicin Enzymes Ephrin-A5 Erythrocyte Membrane Fibroblasts Glutathione Glutathione S-Transferase HL-60 Cells Human Human Cell Line Hydrogen Peroxide In Situ In Situ Nick-End Labeling Injury Iron Overload Isoenzymes JUN gene K-562 K562 Cells Kinetics Knock-out Knockout Mice Laboratories Lipid Peroxidation Lipid Peroxides Liver Measures Mediating Membrane Metabolism Methods Micronutrients Modeling Mus Naphthalene Naphthalenes Necrosis Orthologous Gene Oxidants Oxidative Stress Pathology Phospholipids Phosphorylation Physiological Property Protein Overexpression Proteins Rat Cell Line Rattus Reactive Oxygen Species Recombinants Relative (related person)Rodent Role Signal Pathway Signal Transduction Specific qualifier value Subgroup Superoxide Dismutase TdT-Mediated dUTP Nick End Labeling Assay Testing Testis Tissues Toxic effect Transcription Factor AP-1 Transfection Xanthine Oxidase Xanthines Xenobiotics adduct age related caspase-3 cytotoxicity environmental chemical glutathione peroxidase hGSTA4 in vivo mGSTA4-4 research study stress-activated protein kinase 1 xanthine

项目摘要

DESCRIPTION (provided by applicant): Toxicity of many xenobiotics has been associated with lipid peroxidation (LPO) caused by reactive oxygen species (ROS) generated during their metabolism. Among the antioxidant enzymes, only glutathione peroxidases (GPxs) are known to provide protection against LPO by reducing lipid hydroperoxides. The ?-class glutathione S-transferases (?-GSTs), also show GPx activity towards lipid hydroperoxides, but the physiological role of this activity is not understood. Our preliminary studies show that human hGSTA1-1 and hGSTA2-2 can reduce membrane phospholipid hydroperoxides (PL-OOH) in situ by their GPx activity. Over expression of these enzymes in K562 cells attenuates oxidant (H202 or xenobiotic) induced LPO and cytotoxicity. The over expression of another ?-GST, hGSTA4-4 which detoxifies the end- product of LPO, 4- hydroxynonenal (4-HNE), by conjugating it to glutathione, also protects against oxidant toxicity. We hypothesize that GSTs provide a second line of defense against ROS and act as antioxidant enzymes, which protect cells against toxicity of oxidants/xenobiotics by attenuating LPO. The following specific aims are proposed to test this hypothesis: 1. The physiological significance of the ?-GSTs, GSTA1-1 and GSTA2-2 will be studied by determining their kinetic properties towards LPO products, PL-OOH and 4-HNE. Their contributions in the reduction of PL-OOH in rat and mouse liver will be determined and compared with those of the seleno GPxs. We will examine if the cells over expressing these enzymes are protected against H202 or oxidant xenobiotics (e.g., doxorubucin, CCI4) induced activation of c-Jun N-terminal kinase (JNK), caspase 3, and subsequent apoptosis. 2. Cells will be transfected with the ?-GST isozyme, GSTA4-4, which detoxifies 4-HNE and the toxicity of H202 and oxidant xenobiotics which induce LPO will be compared in the transfected and control cells. Xenobiotics, H202, xanthine/oxidase, DOX induced toxicity and apoptosis will be compared in the control and transfected cells to delineate the role of 4-HNE and GSTA4-4 in oxidative stress mediated signaling. 3. We will examine whether the toxicity of oxidants is enhanced in GSTA4-4 knock out mice because of their inability to detoxify 4-HNE. Since GSTs can be induced by non-toxic micronutrients, these studies will help in devising strategies for negating the toxicity of environmental chemicals and chronic oxidative stress, which leads to age, related degenerative disorders.

描述（由申请人提供）：许多异源生物的毒性与由其代谢过程中产生的活性氧（ROS）引起的脂质过氧化（LPO）有关。在抗氧化剂酶中，只有谷胱甘肽过氧化物酶（GPX）可以通过减少脂质氢过氧化物来保护对LPO的保护。？ - 类谷胱甘肽S-转移酶（？gsts）也显示出对脂质氢过氧化物的GPX活性，但尚不清楚该活性的生理作用。我们的初步研究表明，人类HGSTA1-1和HGSTA2-2可以通过其GPX活性来降低膜磷脂氢过氧化物（PL-OOH）。这些酶在K562细胞中的表达过多减弱氧化剂（H202或异源生物）诱导的LPO和细胞毒性。通过将其连接到谷胱甘肽，可以防止氧化剂毒性，从而使另一个？我们假设GST提供了针对ROS的第二道防线，并充当抗氧化剂酶，可通过减弱LPO来保护细胞免受氧化剂/异生元的毒性。提出了以下具体目的来检验这一假设：1。将研究？-GST，GSTA1-1和GSTA2-2的生理意义，通过确定其对LPO产品，PL-OOH和4-HNE的动力学特性来研究。它们在大鼠肝脏和小鼠肝脏中PL-OH的降低方面的贡献将被确定并与Seleno GPX的贡献。我们将检查表达这些酶的细胞是否受到H202或氧化剂异种生物的保护（例如，毒bubucin，cci4）诱导的C-JUN N末端激酶（JNK），caspase 3和随后的凋亡诱导的激活。 2。细胞将用？-GST同工酶GSTA4-4转染，它会使4-HNE排毒，H202和H202的毒性和氧化剂异源毒素的毒性将在转染和对照细胞中进行比较。异种生物，H202，黄嘌呤/氧化酶，DOX诱导的毒性和凋亡将在对照和转染细胞中进行比较，以描绘4-HNE和GSTA4-4在氧化应激介导的信号传导中的作用。 3。我们将检查GSTA4-4中氧化剂的毒性是否增加了小鼠，因为它们无法排毒4-HNE。由于可以通过无毒的微量营养素诱导GST，因此这些研究将有助于制定否定环境化学物质和慢性氧化应激的毒性的策略，从而导致年龄，相关的退行性疾病。