Protection of Oxidant Toxicity By GSTs

GST 保护氧化剂毒性

• 批准号: 7742093
• 负责人: YOGESH Chandra AWASTHI
• 金额: $ 44.3万
• 依托单位: UNIVERSITY OF NORTH TEXAS HLTH SCI CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-21 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7742093
• 关键词: 4 hydroxynonenal; Affect; Animals; Antioxidants; Apoptosis; Apoptotic; Attenuated; Binding; Binding Sites; CD95 Antigens; CYP2E1 gene; Cell Line; Cell Nucleus; Cell model; Cells; Cessation of life; Chemicals; Clinical; Complex; Cytoplasm; Data; Degenerative Disorder; Doxorubicin; Drug Metabolic Detoxication; Drug toxicity; Embryo; Enzymes; Excision; Experimental Designs; Exposure to; Fibroblasts; Fourier transform ion cyclotron resonance; Funding; Gene Targeting; Glutathione; Glutathione S-Transferase; Hand; In Situ; In Vitro; Intraperitoneal Injections; Knockout Mice; Lipid Peroxidation; Lipid Peroxides; Liposomes; Liver; Mediating; Methods; Modeling; Mus; Nature; Necrosis; Nuclear; Oxidants; Oxidative Stress; Pathway interactions; Pharmaceutical Preparations; Phosphorylation; Prevention; Prevention strategy; Process; Proteins; Recombinant Proteins; Recombinants; Recruitment Activity; Roentgen Rays; Role; Signal Pathway; Signal Transduction; Stress; TP53 gene; Testing; Tissues; Toxic effect; Transcription Repressor/Corepressor; Transfection; Tumor Necrosis Factor Ligand Superfamily Member 6; Xenobiotics; base; impaired capacity; in vitro testing; in vivo; irradiation; novel; pro-caspase-8; proteoliposomes; public health relevance; reconstitution; trafficking

DESCRIPTION (provided by applicant): 4-Hydroxynonenal (4-HNE), a stable end-product of lipid peroxidation (LPO) can cause toxicity through apoptosis and necrosis. During current funded years, we have established that GSTA4-4 and RLIP76 are the major determinants of the intracellular concentrations of 4-HNE. Our preliminary studies show that 4-HNE binds to the death receptor Fas and induces Fas-mediated apoptosis through a novel pathway that is distinct from the canonical pathway in which Fas binds to FADD and recruits procaspase8 to assemble the death inducing signaling complex (DISC) for eventual execution of apoptosis. 4-HNE also binds to Daxx, a transcription repressor and causes its translocation from nucleus to cytoplasm to affect Fas-mediated apoptosis. In addition, 4-HNE promotes phosphorylation and translocation of p53 and activates its pro-apoptotic gene targets. Since exposure to oxidants causes LPO, we hypothesize that part of toxicity of oxidants is contributed by the pro-apoptotic effects of 4-HNE and that the over expression of GSTA4-4 (which catalyzes conjugation of 4-HNE to GSH) and RLIP76 (which mediates transport of GS- HNE conjugate) should attenuate the oxidant-induced toxicity by lowering the intracellular levels of 4-HNE. This hypothesis is supported by our preliminary studies showing that: a) Fas- and p53-mediated apoptosis is inhibited by the over-expression of GSTA4-4. b) Liposomal delivery of RLIP76 to RLIP76 (-/-) mice (which are more sensitive to oxidant toxicity) protects these mice from toxicity. In Specific Aim 1 this hypothesis will be tested through proposed in-vitro studies using HepG2 cells transfected with Cyp2E1 and two model oxidant compounds, CCl4, and doxorubicin (DOX). In these studies we will also delineate the mechanisms of 4-HNE induced, Fas- mediated apoptosis and the regulatory role of Daxx and GSTs. Since our preliminary studies show that 4-HNE binds to Fas, Daxx, and p53, and affects their functions and/or cellular localization, studies are proposed in Specific Aim 2 to delineate the nature and significance of the interactions between 4-HNE and these proteins. In Specific Aim 3, we hypothesize that RLIP76 (-/-) mice with impaired capacity to detoxify 4-HNE would be more sensitive to the toxicity of these agents and administration of RLIP76 proteoliposomes should attenuate this toxicity. This will be tested through proposed in vivo studies by comparing the toxicity of these oxidants in RLIP76 (-/-) and RLIP76 (+/+) mice, with and without treatment with RLIP76 proteolipsomes. In these studies we will also compare the 4-HNE levels and the extent of apoptosis in the liver of different groups of mice. Besides providing fundamental novel information on the mechanisms of oxidant toxicity and the role of 4-HNE in oxidative stress associated degenerative disorders, studies proposed in this application should also help to develop prevention strategies against the toxicity of drugs and xenobiotics which is a major clinical and environmental problem. PUBLIC HEALTH RELEVANCE: Proposed studies on the protective role of glutathione transferases and RLIP76 against oxidant toxicity should help in developing strategies for alleviating the toxicity of environmental oxidants and drugs and also for the prevention and treatment of oxidative stress-induced degenerative diseases.

描述（由申请人提供）：4-羟基烯烯（4-HNE），脂质过氧化（LPO）的稳定终产物可通过细胞凋亡和坏死引起毒性。在目前的资助年中，我们已经确定GSTA4-4和RLIP76是4-HNE细胞内浓度的主要决定因素。我们的初步研究表明，4-HNE与死亡受体FAS结合，并通过一种与规范途径不同的途径诱导Fas介导的凋亡，该途径与法典途径不同，在该途径中，FAS与FADD结合并募集Procaspase8以组装死亡诱导信号复合物（DISC）以最终执行凋亡。 4-HNE还与DAXX结合，DAXX是转录抑制剂，并导致其从核向细胞质的易位影响FAS介导的凋亡。此外，4-HNE促进p53的磷酸化和易位，并激活其促凋亡基因靶标。由于暴露于氧化剂会导致LPO，因此我们假设氧化剂的毒性部分是由4-HNE的促凋亡作用以及GSTA4-4的促凋亡作用造成的，并且GSTA4-4的过度表达（催化4-HNE与GSH的结合）和RLIPLIP76（由GS-HNE Con​​coniatient-conjugate的氧化能力降低了），这应介导氧化剂的氧化物 - 均应介绍氧化氧化物的氧化物。 4-HNE的水平。我们的初步研究表明：a）a）FAS和p53介导的凋亡受到GSTA4-4的过表达抑制。 b）RLIP76至RLIP76（ - / - ）小鼠（对氧化剂毒性更敏感）的脂质体递送可保护这些小鼠免受毒性。在特定的目标1中，该假设将通过使用CYP2E1转染的HEPG2细胞和两种模型氧化剂化合物CCL4和阿霉素（DOX）进行检验。在这些研究中，我们还将描述4-HNE诱导的，FAS介导的凋亡以及DAXX和GST的调节作用的机制。由于我们的初步研究表明4-HNE与FAS，DAXX和P53结合并影响其功能和/或细胞定位，因此在特定的目标2中提出了研究，以描绘4-HNE和这些蛋白质之间相互作用的性质和意义。在特定的目标3中，我们假设RLIP76（ - / - ）小鼠排毒4-HNE的能力受损将对这些药物的毒性和rip76蛋白脂质体的给药更敏感。通过比较RLIP76（ - / - ）和rlip76（+/+）小鼠的这些氧化剂的毒性，并与RLIP76蛋白脂质体治疗，将通过比较这些氧化剂的毒性来测试这一点。在这些研究中，我们还将比较不同小鼠组的肝脏中4-HNE水平和凋亡程度。除了提供有关氧化剂毒性机制以及4-HNE在氧化应激相关的退行性疾病中的作用的基本新信息外，该应用中提出的研究还应有助于制定预防策略，以防止药物和异种生物的毒性，这是主要的临床和环境问题。公共卫生相关性：关于谷胱甘肽转移酶和RLIP76对氧化剂毒性的保护作用的拟议研究，应有助于制定策略，以减轻环境氧化剂和药物的毒性，以及预防和治疗氧化应激型诱导的变性性疾病。