Regulation of Contractility During Ischemia-Reperfusion

缺血再灌注过程中收缩力的调节

• 批准号: 7216736
• 负责人: OZGUR OGUT
• 金额: $ 28.74万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-04-01 至 2011-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7216736
• 关键词: Actins; Actomyosin; Actomyosin Adenosinetriphosphatase; Address; Aerobic; Affect; Affinity Chromatography; Agreement; Applications Grants; Area; Biochemical; Cardiac Myocytes; Cell Respiration; Cessation of life; Condition; Consumption; Contractile Proteins; Coronary artery; Coupled; Data; Defect; Depressed mood; Diagnosis; Equilibrium; Event; Experimental Models; Fiber; Filament; Free Radicals; Goals; Heart; Immunoprecipitation; In Vitro; Ischemia; Length; Life; Mass Spectrum Analysis; Measurement; Mediating; Metabolism; Methods; Mitochondria; Modeling; Modification; Molecular Analysis; Muscle Fibers; Muscle Proteins; Myocardial Infarction; Myocardial Ischemia; Myocardium; Myosin ATPase; Nature; Nitrogen; Oxidation-Reduction; Patients; Phosphocreatine; Phosphorylation; Physiological; Physiological reperfusion; Population; Post-Translational Protein Processing; Principal Investigator; Process; Production; Protein Biosynthesis; Proteins; Proteolysis; Rate; Rattus; Recovery; Regulation; Reperfusion Therapy; Research; Research Personnel; Role; Severities; Skin; Stress; Striated Muscles; Techniques; Testing; Thin Filament; Time; Tropomyosin; Troponin; Two-Dimensional Gel Electrophoresis; Western Blotting; Xanthines; anaerobic glycolysis; cell injury; design; driving force; experience; genetic regulatory protein; insight; interest; novel; programs; research study; response; xanthine

DESCRIPTION (provided by applicant): Myocardial infarction is prevalent with -1 million patients diagnosed each year. To better understand the cellular conditions leading to cardiomyocyte damage and death, experimental models have mimicked the ischemia - reperfusion (I-R) experienced by the myocardium. The decrease in ATP with I-R is often considered the driving force behind the contractility decline. However, recent research suggests that changes intrinsic to the contractile filaments, such as protein proteolysis or redox-dependent protein modifications, also influence contractility during I-R. The preliminary data in this application indicate that a decline in cardiac muscle contractility occurs with 30' of ischemia and is largely reversed by 60' of reperfusion. The reversible decline in contractility was independent of ATP availability, suggesting that intrinsic changes to the contractile filaments best described the decline. However, this timeframe is insufficient for protein proteolysis during ischemia to be rescued by protein synthesis and re-assembly during reperfusion. Therefore, these changes in contractility may reflect reversible, covalent modifications to proteins of the contractile filaments rather than their proteolysis. Consistent with this hypothesis, preliminary data demonstrate that a reversible modification of actin occurs during I-R, affecting it's interaction with tropomyosin. Therefore, this grant application aims to investigate fibre contractility during I-R, and characterize the reversible modifications to proteins of the contractile filaments that underlie the changes in contractility. The application will test the hypothesis that ischemia-reperfusion results in reversible, covalent modifications to proteins of the cardiac muscle thin filament, consequently limiting contractility through changes in the association of thin filament regulatory proteins. This hypothesis will be examined by: i) determining the effect of I-R on the contractility of cardiac muscle fibres; ii) characterizing the I-R dependent modification of actin, and determining if I-R results in covalent modifications to other thin filament proteins; iii) determining the effect of modification of actin on thin filament assembly as well as the actin activated myosin ATPase. These findings will provide novel insight into the nature of the contractile deficit during I-R, with emphasis on the state of the cardiac muscle thin filament proteins and their effect on contractility.

描述(申请人提供)：心肌梗死很普遍，每年有100万名患者被诊断出来。为了更好地了解导致心肌细胞损伤和死亡的细胞条件，实验模型模拟了心肌经历的缺血-再灌注(I-R)。随着I-R，ATP的减少通常被认为是收缩能力下降背后的驱动力。然而，最近的研究表明，收缩细丝固有的变化，如蛋白质分解或氧化还原依赖的蛋白质修饰，也会影响I-R过程中的收缩能力。这项应用的初步数据表明，心肌收缩能力的下降发生在缺血30‘，并在很大程度上逆转再灌流60’。收缩能力的可逆性下降与三磷酸腺苷的可获得性无关，表明收缩细丝的内在变化最好地描述了这种下降。然而，这一时间框架不足以使缺血期间的蛋白质分解通过再灌注期间的蛋白质合成和重新组装来挽救。因此，这些收缩能力的变化可能反映了对收缩细丝蛋白质的可逆的共价修饰，而不是它们的蛋白分解。与这一假设一致的是，初步数据表明，肌动蛋白在I-R过程中发生可逆修饰，影响其与原肌球蛋白的相互作用。因此，这项拨款申请旨在研究I-R期间纤维的收缩性能，并表征收缩细丝蛋白质的可逆修饰，这是收缩性能变化的基础。这项应用将检验这样一种假设，即缺血-再灌注导致对心肌细丝蛋白质的可逆、共价修饰，从而通过改变细丝调节蛋白的关联来限制收缩能力。这一假设将通过：i)确定I-R对心肌纤维收缩性能的影响；ii)表征依赖I-R的肌动蛋白的修饰，并确定I-R是否导致对其他细丝蛋白的共价修饰；iii)确定肌动蛋白的修饰对细丝组装以及肌动蛋白激活的肌球蛋白ATPase的影响。这些发现将为了解I-R期间收缩缺陷的性质提供新的见解，重点是心肌细丝蛋白的状态及其对收缩能力的影响。