Translational Control of Oxidative Stress in Myocardial Infarction

心肌梗死中氧化应激的转化控制

• 批准号: 7851396
• 负责人: QIN M CHEN
• 金额: $ 45.47万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2012-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7851396
• 关键词: 5' Untranslated Regions; Address; Animals; Anterior Descending Coronary Artery; Antioxidants; Apoptosis; Automobile Driving; BIRC4 gene; Binding; Binding Proteins; Cardiac; Cardiac Myocytes; Characteristics; Code; Computer Simulation; Coupled; Cytoprotection; DNA; Data; Databases; Disease; Dose; Drug Metabolic Detoxication; Firefly Luciferases; GC Rich Sequence; Gene Expression; Genes; Genetic Transcription; Genomics; Grant; Heart failure; Human; In Vitro; Initiator Codon; Injury; Internal Ribosome Entry Site; Investigation; Ischemia; Knockout Mice; Knowledge; Left; Link; Measurement; Measures; Mediating; Messenger RNA; Mus; Mutate; Myocardial; Myocardial Infarction; Myocardial Ischemia; Myocardial tissue; Myocardium; NF-E2-related factor 2; Nucleotides; Organ; Oxidants; Oxidative Stress; Phase; Play; Polyribosomes; Promoter Regions; Proteins; Proteomics; RNA; RNA Probes; Rattus; Reactive Oxygen Species; Recruitment Activity; Regulation; Renilla Luciferases; Reperfusion Therapy; Reporter; Research; Response Elements; Ribonucleases; Ribosomes; Role; Set protein; Site; Staging; Stress; Stress-Induced Protein; Stretching; Structure; Structure-Activity Relationship; Technology; Testing; Tissues; Trans-Activators; Transfection; Translating; Translations; Work; artery occlusion; base; cell type; genome-wide; infancy; preconditioning; programs; protective effect; public health relevance; response; stem; transcription factor; translation assay

DESCRIPTION (provided by applicant): Ischemic reperfusion (I/R) is known to trigger an increase of reactive oxygen species in the myocardium. Although high levels of oxidants can cause damages, low doses of oxidant elicit a protective effect, such as during preconditioning induced by cycles of brief I/R. Our recent data suggest that induction of antioxidant and detoxification genes dominates the gene expression network of oxidants in cardiomyocytes. A master switch controlling the expression of these genes is the transcription factor Nrf2. We found that 2 to 4 cycles of 5 min ischemia and 5 min reperfusion cause elevation of Nrf2 protein in the myocardium. With isolated cardiomyocytes, oxidants cause rapid onset of Nrf2 protein translation. Stress generally causes global reduction of protein translation. Recent studies suggest that several genes containing an Internal Ribosomal Entry Site (IRES) in the 5' Untranslated Region (5'UTR) of mRNA can escape the general translational control and undergo stress induced protein translation. A group of IRES Trans-Acting Factors (ITAFs) appears to be critical in recruiting the ribosomes to initiate the translation of these genes. Little is known about which proteins and how they are translated when the myocardium or cardiomyocytes encounter oxidative stress. We plan to take advantage of genomic and proteomic technologies to test the hypothesis that "cycles of brief I/R cause selective increase of Nrf-2 protein in the myocardium through IRES mediated translation". The Specific Aims include 1) Test that Nrf2 protein translation occurs in the myocardium by cycles of brief I/R and mediates preconditioning induced cardiac protection; 2) Test that lack of well defined Kozak sequence and formation of stable "stems and loops" secondary structure in 5'UTR enable a battery of genes to undergo I/R induced protein translation; 3) Test that Nrf2 mRNA contains an IRES that allows rapid protein translation in cardiomyocytes following cycles of brief I/R or low dose of oxidants; 4) Test that cardiomyocytes express a unique set of ITAFs to regulate Nrf2 protein translation in response to I/R. The field of stress induced protein translation is in its stage of infancy. Although Nrf2 plays a critical role in cytoprotection among various cell types, the function and regulation of Nrf2 have not been well studied in cardiomyocytes. Studying the mechanism of protein translation under oxidative stress becomes a necessary task in understanding the transition to heart failure from adaptive response. PUBLIC HEALTH RELEVANCE: This grant proposes to study the mechanism of Nrf2 protein translation in cardiomyocytes and in the myocardium following oxidative stress.

描述（由申请人提供）：已知缺血再灌注（I/R）会引发心肌中活性氧的增加。虽然高水平的氧化剂会造成损害，但低剂量的氧化剂会产生保护作用，例如在短暂 I/R 周期诱导的预处理过程中。我们最近的数据表明，抗氧化和解毒基因的诱导主导了心肌细胞中氧化剂的基因表达网络。控制这些基因表达的主开关是转录因子 Nrf2。我们发现2至4个周期的5分钟缺血和5分钟再灌注会导致心肌中Nrf2蛋白升高。对于分离的心肌细胞，氧化剂会导致 Nrf2 蛋白快速翻译。压力通常会导致蛋白质翻译的整体减少。最近的研究表明，mRNA 5' 非翻译区 (5'UTR) 中含有内部核糖体进入位点 (IRES) 的几个基因可以逃避一般翻译控制并进行应激诱导的蛋白质翻译。一组 IRES 反式作用因子 (ITAF) 似乎对于招募核糖体以启动这些基因的翻译至关重要。当心肌或心肌细胞遇到氧化应激时，哪些蛋白质以及它们如何翻译，人们知之甚少。我们计划利用基因组和蛋白质组学技术来检验“短暂 I/R 周期通过 IRES 介导的翻译导致心肌中 Nrf-2 蛋白选择性增加”的假设。具体目标包括 1) 测试 Nrf2 蛋白翻译通过短暂的 I/R 周期在心肌中发生并介导预处理诱导的心脏保护； 2) 测试 5'UTR 中缺乏明确的 Kozak 序列和稳定的“茎和环”二级结构的形成使得一系列基因能够进行 I/R 诱导的蛋白质翻译； 3) 测试Nrf2 mRNA是否含有IRES，该IRES允许在短暂I/R或低剂量氧化剂循环后在心肌细胞中快速翻译蛋白质； 4) 测试心肌细胞表达一组独特的 ITAF 来调节 Nrf2 蛋白翻译以响应 I/R。应激诱导的蛋白质翻译领域正处于起步阶段。尽管Nrf2在多种细胞类型的细胞保护中发挥着关键作用，但Nrf2在心肌细胞中的功能和调节尚未得到充分研究。研究氧化应激下蛋白质翻译机制成为理解适应性反应向心力衰竭转变的必要任务。公共健康相关性：该资助计划研究氧化应激后心肌细胞和心肌中 Nrf2 蛋白翻译的机制。