Regulation of Contractility During Ischemia-Reperfusion

缺血再灌注过程中收缩力的调节

• 批准号: 7837479
• 负责人: OZGUR OGUT
• 金额: $ 22.82万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7837479
• 关键词: Actins; Actomyosin; Actomyosin Adenosinetriphosphatase; Address; Aerobic; Affect; Affinity Chromatography; Agreement; Applications Grants; Area; Biochemical; Cardiac Myocytes; Cell Respiration; Cessation of life; Consumption; Contractile Proteins; Coronary artery; Coupled; Data; Defect; 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; Population; Post-Translational Protein Processing; Principal Investigator; Process; Production; Protein Biosynthesis; Proteins; Proteolysis; 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; depressed; design; driving force; experience; genetic regulatory protein; in vitro testing; insight; interest; novel; oxidative damage; programs; research study; response

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.

心肌梗塞很普遍，每年诊断出-100万患者。为了更好地理解 细胞状况导致心肌细胞损伤和死亡，实验模型模仿了 心肌经历缺血-再灌注（I-R）。 ATP 随 I-R 的减少通常是 被认为是收缩力下降的驱动力。然而，最近的研究表明 收缩丝固有的变化，例如蛋白质水解或氧化还原依赖性蛋白质 修饰，也会影响 I-R 期间的收缩性。本申请中的初步数据表明 心肌收缩力下降发生在缺血 30' 时，并且在缺血 60' 时基本逆转。 再灌注。收缩力的可逆性下降与 ATP 可用性无关，这表明 收缩丝的内在变化最能描述这种衰退。然而，这个时间范围是 缺血期间的蛋白质水解不足以通过蛋白质合成和重组来挽救 再灌注。因此，收缩性的这些变化可能反映了可逆的共价修饰 收缩丝的蛋白质而不是它们的蛋白水解。与这一假设相一致，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。因此，本次拨款申请旨在研究 I-R 期间的纤维收缩性，以及 表征收缩丝蛋白的可逆修饰，这是变化的基础 收缩性。该应用程序将测试缺血再灌注导致可逆、共价 心肌细丝蛋白质的修饰，从而通过限制收缩性 细丝调节蛋白关联的变化。该假设将通过以下方式检验： i) 确定 I-R 对心肌纤维收缩力的影响； ii) 表征 I-R 依赖性 肌动蛋白的修饰，并确定 I-R 是否会导致其他细丝蛋白的共价修饰；三） 确定肌动蛋白修饰对细丝组装以及肌动蛋白激活的肌球蛋白的影响 ATP酶。这些发现将为 I-R 期间收缩缺陷的性质提供新的见解， 强调心肌细丝蛋白的状态及其对收缩性的影响。