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: 7658039
• 负责人: QIN M CHEN
• 金额: $ 45.33万
• 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 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7658039
• 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）会触发心肌中活性氧的增加。虽然高水平的氧化剂会导致损伤，但低剂量的氧化剂会产生保护作用，例如在短暂I/R循环诱导的预处理期间。我们最近的数据表明，诱导抗氧化和解毒基因占主导地位的基因表达网络的氧化剂在心肌细胞。控制这些基因表达的主开关是转录因子Nrf 2。我们发现，2至4个周期的5分钟缺血和5分钟再灌注引起心肌Nrf 2蛋白的升高。对于分离的心肌细胞，氧化剂导致Nrf 2蛋白翻译的快速发生。压力通常会导致蛋白质翻译的整体减少。最近的研究表明，在mRNA的5'非翻译区（5' UTR）中含有内部核糖体进入位点（IRES）的几个基因可以逃脱一般的翻译控制，并经历应激诱导的蛋白质翻译。一组IRES反式作用因子（ITAF）似乎在募集核糖体以启动这些基因的翻译中起关键作用。当心肌或心肌细胞遇到氧化应激时，哪些蛋白质以及它们是如何翻译的，目前还知之甚少。我们计划利用基因组学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蛋白的选择性增加”的假设。具体目的包括：1）检测短暂I/R循环在心肌中发生Nrf 2蛋白翻译并介导预处理诱导的心脏保护作用：2）检测缺乏明确的Kozak序列和在5 'UTR形成稳定的“茎环”二级结构使得一组基因能够经历I/R诱导的蛋白翻译; 3）测试Nrf 2 mRNA包含IRES，其允许在短暂I/R或低剂量氧化剂循环后在心肌细胞中快速蛋白质翻译; 4）测试心肌细胞表达一组独特的ITAF以响应I/R调节Nrf 2蛋白质翻译。应激诱导的蛋白质翻译领域还处于起步阶段。虽然Nrf 2在各种细胞类型中的细胞保护中起着关键作用，但Nrf 2的功能和调节在心肌细胞中尚未得到充分研究。研究氧化应激条件下蛋白质的翻译机制是理解适应性反应向心力衰竭转变的必要任务。公共卫生关系：该基金建议研究心肌细胞和氧化应激后心肌中Nrf 2蛋白翻译的机制。