Myocardial Infarct in Aging Animals and dATP Therapy

老龄动物心肌梗死和 dATP 治疗

• 批准号: 9565690
• 负责人: MICHAEL REGNIER
• 金额: $ 68.26万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-09-30 至 2019-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9565690
• 关键词: Actins; Affect; Age; Aging; Animal Model; Animals; Binding; Biological Assay; Canis familiaris; Cardiac; Cardiac Myocytes; Cells; Coupled; Data; Development; Dilated Cardiomyopathy; Elderly; Enzymes; Exercise Tolerance; Family suidae; Fatigue; Functional disorder; Goals; Health; Health Benefit; Health Care Costs; Heart; Heart failure; Home Nursing Care; Human; Impairment; Infarction; Kinetics; Lead; Left; Left Ventricular Function; Life; Longevity; Measures; Mediating; Metabolic; Metabolism; Mitochondria; Modeling; Morphology; Mus; Muscle; Muscle Weakness; Muscle function; Myocardial Infarction; Myocardium; Myofibrils; Myopathy; Myosin ATPase; Nucleotides; Organ; Pathologic; Patients; Performance; Performance at work; Physiology; Populations at Risk; Preparation; Property; Protein Isoforms; Proteomics; Public Health; Quality of life; Relaxation; Reporting; Resistance; Respiration; Ribonucleotide Reductase; Risk; Rodent; Role; Running; Skeletal Muscle; Skeletal Muscle Myosins; Skin; Speed; Striated Muscles; System; Testing; Tissues; Transgenic Organisms; Ventricular; Viral; Viral Vector; Work; adeno-associated viral vector; age related; aged; aging population; exercise capacity; exercise intolerance; experimental study; gene therapy; heart function; heart metabolism; improved; improved mobility; interdisciplinary approach; juvenile animal; mature animal; metabolic profile; metabolomics; muscle aging; muscle metabolism; novel; novel therapeutics; nucleotide metabolism; older patient; overexpression; promoter; resistance exercise; response; skeletal; treadmill; vector; young adult

ABSTRACT The goal of this project is two-fold: 1) to determine how age compounds the effect of myocardial infarct (MI) on heart function and how this affects skeletal muscle function and exercise tolerance; and 2) to determine the ability of 2 deoxy-ATP (dATP) to affect heart and skeletal muscle performance, metabolism and exercise tolerance in age and MI induced heart failure. Most studies of performance decline with MI are done with young animal models, to look at infarct specific effects. However, MI occurs most often in the elderly, and it is not clear the extent to which this compounds pathologic effects at the system, organ and cell levels. Thus, we will study how age impacts the effects of MI on heart and skeletal muscle contractile and metabolic function. We will then use this model to study cardiac-specific vs. cardiac + skeletal muscle elevation of dATP. We have previously reported that dATP enhances contraction in demembranated cardiac and skeletal muscle by increasing myosin binding to actin (crossbridge formation) and crossbridge cycling. We have also reported that cellular levels of dATP can be elevated in the heart and skeletal muscle via transgenic or viral vector-mediated or over-expression of the enzyme Ribonucleotide Reductase (RNR). Both of these approaches enhance left ventricular (LV) heart function and increases the magnitude and speed of cardiomyocyte contraction & relaxation in normal hearts and rescues LV function of infarcted hearts of rodents and pigs. These previous MI studies were done in young adult animal and we did not determine how cardiac-specific elevation of dATP affected skeletal muscle or exercise tolerance. In preliminary data we demonstrate that 1) both demembranated cardiac and skeletal muscle from old mice have enhanced contraction when dATP (vs. ATP) is the substrate for contraction, 2) transgenic young mice with elevated heart and skeletal muscle [dATP] have greater exercise capacity, faster treadmill running and fatigue resistance, and 3) elevated cardiac RNR and dATP may protect against transition from an oxidative to glycolytic cardiac metabolic profile following MI (in young mice) and rescue this `more youthful' oxidative profile in old mice. In the proposed experiments we will determine if AAV-RNR vectors can improve cardiac and skeletal muscle performance, exercise capacity and metabolic performance of old mice with and without MI. We will compare vectors with cardiac-specific vs. striated muscle-specific expression of RNR. Thus our proposal offers a unique model to study how specifically targeting the heart to improve its performance can have secondary beneficial effects in skeletal muscle. Function will be measured at whole organ, cell and myofibril levels for both cardiac and skeletal muscle and coupled with measures of metabolic efficiency and activity, mitochondrial function, and metabolomics and proteomic analysis. This multi- scale analysis, using interdisciplinary approaches, will provide information for mechanistic interpretations. The results from these studies will determine feasibility of our approach (AAV-RNR mediated elevation of dATP in muscle) for treatment of heart failure and other age-related declines in cardiac function and exercise tolerance.

本研究的目的有两个：1）确定年龄是如何复合心肌梗死的影响的。 心肌梗死（MI）对心脏功能的影响以及这如何影响骨骼肌功能和运动耐量;以及2） 确定2脱氧ATP（dATP）影响心脏和骨骼肌性能、代谢和 老年运动耐量和心肌梗死诱发的心力衰竭。大多数关于MI导致性能下降的研究都是在 用年轻的动物模型来观察梗塞的特异性效应。然而，MI最常发生在老年人中，并且 目前尚不清楚这在系统、器官和细胞一级造成病理影响的程度。因此，在本发明中， 我们将研究年龄如何影响心肌梗死对心脏和骨骼肌收缩和代谢功能的影响。 然后，我们将使用该模型研究心脏特异性与心脏+骨骼肌的dATP升高。我们有 先前报道dATP通过以下途径增强去膜心肌和骨骼肌的收缩： 增加肌球蛋白与肌动蛋白的结合（横桥形成）和横桥循环。我们还报告说， 通过转基因或病毒载体介导， 或核糖核苷酸还原酶（RNR）的过表达。这两种方法都增强了左 心室（LV）心脏功能，并增加心肌细胞收缩和舒张的幅度和速度 在正常心脏和挽救啮齿动物和猪的梗死心脏的LV功能。这些先前的MI研究 在年轻的成年动物中进行，我们没有确定心脏特异性dATP升高如何影响 骨骼肌或运动耐量。在初步的数据中，我们证明：1）两个去膜心脏 当dATP（相对于ATP）是 收缩，2）心脏和骨骼肌[dATP]升高的转基因年轻小鼠有更多的运动 容量，更快的跑步机跑步和抗疲劳能力，以及3）心脏RNR和dATP升高可能保护 对抗MI（幼龄小鼠）和救援后心脏代谢谱从氧化转变为糖酵解 这种“更年轻”的氧化特征。在所提出的实验中，我们将确定AAV-RNR 载体可以改善心脏和骨骼肌的性能，运动能力和代谢性能， 有和没有MI的老年小鼠。我们将比较心脏特异性与横纹肌特异性 RNR的表达。因此，我们的建议提供了一个独特的模型来研究如何专门针对心脏， 改善其性能可在骨骼肌中具有次级有益效果。功能将在 心脏和骨骼肌的整个器官、细胞和肌原纤维水平，并结合 代谢效率和活性、线粒体功能以及代谢组学和蛋白质组学分析。这多- 使用跨学科方法进行的尺度分析将为机械解释提供信息。的 这些研究的结果将确定我们方法的可行性（AAV-RNR介导的dATP升高， 肌肉）用于治疗心力衰竭和其他与年龄相关的心脏功能和运动耐量下降。