Troponin and Heart Function in Heath and Disease

健康和疾病中的肌钙蛋白和心脏功能

基本信息

批准号：
7487371
负责人：
JOSEPH Mark METZGER
金额：
$ 35.89万
依托单位：
UNIVERSITY OF MINNESOTA
依托单位国家：
美国
项目类别：
财政年份：
1997
资助国家：
美国
起止时间：
1997-12-08 至 2010-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7487371
关键词：
Acidosis Actins Adult Animals Automobile Driving Biochemical Biology Cardiac Cardiac Myocytes Cardiomyopathies Cardiovascular system Cellular Structures Chemicals Codon Nucleotides Country Disease Engineering Experimental Genetics Experimental Models Failure Functional disorder Gene Transfer Gene Transfer Techniques Genes Genetic Engineering Goals Head Health Heart Heart Diseases Heart failure Hemoglobin Histidine Human Investigation Ischemia Mechanics Mediating Microfilaments Modeling Molecular Morbidity - disease rate Muscle Muscle Cells Myocardial Ischemia Myocardium Neonatal Output Performance Physiological Physiology Play Protein Isoforms Radio Range Relative (related person)Research Research Personnel Rodent Role Sarcomeres Site-Directed Mutagenesis Skeletal system Structure Telemetry Testing Troponin Troponin C Troponin I Wild Type Mouse Work base design fetal heart function improved in vivo insight mortality programs research study response sensor stem vector

项目摘要

DESCRIPTION (provided by applicant): The overarching goal of this research is to design, test, and implement sarcomere-based therapies for contractile dysfunction in ischemic heart failure (IMF). Health relevance stems from IMF being a leading cause of combined mortality and morbidity in this country. In ischemic myocardium, the intracellular acidosis that accrues in ischemic muscle uncouples the sarcomere from Ca2+; hence, the contractile machinery does not respond effectively to the normal Ca2+ transient. Troponin I (Tnl) is a molecular switch of the sarcomere and has a central, isoform-dependent role in ischemic contractile failure. In fetal/neonatal heart, the slow skeletal Tnl (ssTnl) gene is expressed and confers protection from ischemia-mediated contractile failure relative to the cardiac Tnl (cTnl) isoform expressed exclusively in adult heart. We found that a single histidine residue, present in ssTnl and absent in cTnl, confers pH-dependent alterations in the molecular switch function of Tnl, reminiscent of archetypal histidine buttons in biology, e.g., the pH-dependent histidine switch in hemoglobin. The overarching hypothesis of this proposal is histidine-substituted cTnl serves as a titratable, "myofilament sensor", that tunes the gain-of-contractile function in response to the changing biochemical milieu of the ischemic and failing myocardium in vivo.The Specific Aims are: (Aim 1) To determine the mechanism underlying histidine-substituted cTnl's titratable gain-of-contractile function by targeted modifications at cTnl codon 164 in rodent and human adult cardiac myocytes. Cardiac Tnl codon 164 resides in the molecular switch regulatory domain of cTnl that toggles between actin and troponin C (TnC) during the contractile cycle. Hypothesis. The protonated chemical switch of cTnl A164H, as in the case of ischemic myocardium, strengthens Tnl-TnC interactions. (Aim 2) To determine in genetically engineered animals in vivo the short- and long-term cardiovascular effects of cTnl A164H in models of ischemia and failure. Hypothesis: Cardiac Tnl A164H expression by transgenesis and by adeno-associated vector systemic gene transfer in vivo will confer long-term improvements in systolic and diastolic performance, compared to wild-type mice, by virtue of improved synergy between the sarcomere and intracellular Ca2+ in experimental and genetic models of myocardial ischemia, stunning, and failure.

描述（由申请人提供）：这项研究的总体目标是设计，测试和实施基于肉瘤的缺血性心力衰竭（IMF）的收缩功能障碍的疗法。健康相关性源于国际货币基金组织是该国死亡率和发病率综合的主要原因。在缺血性心肌中，缺血性肌肉中产生的细胞内酸中毒是从Ca2+中脱离的肌动症。因此，收缩机械对正常的Ca2+瞬变没有有效响应。肌钙蛋白I（TNL）是肌膜的分子转换，在缺血性收缩衰竭中具有中心的同工型依赖性作用。在胎儿/新生儿心脏中，表达慢骨骨骼TNL（SSTNL）基因，并赋予相对于心脏中专有表达的心脏TNL（CTNL）同工型的缺血介导的收缩衰竭。我们发现，SSTNL中存在的单个组氨酸残基，在CTNL中不存在，赋予了TNL分子开关功能的pH依赖性改变，让人联想到生物学中的原型组氨酸按钮，例如血红蛋白中的pH依赖性组氨酸开关。该提案的总体假设是组氨酸取代的CTNL作为可滴定的“肌丝传感器”，它可以响应于不断变化的缺血性和失败的vivo的生物化学环境而响应于合成的功能。在啮齿动物和人类成人心肌细胞中，通过CTNL密码子164进行靶向修饰获得收集功能。心脏TNL密码子164位于CTNL的分子开关调节结构域中，该结构域在收缩循环中在肌动蛋白和肌动蛋白C（TNC）之间切换。假设。 CTNL A164H的质子化学转换（如缺血性心肌）增强了TNL-TNC相互作用。（目标2）在体内确定基因工程动物中，CTNL A164H在缺血和衰竭模型中的短期和长期心血管效应。假设：与野生型小鼠相比，通过sarcomere和netarular therector of genemia and genemia of Myocardial of Myocardial，与野生型小鼠相比，与野生型小鼠相比，与野生型小鼠相比，与野生型小鼠相比，与野生型小鼠相比，与野生型小鼠相比，通过转基因和腺相关的载体全身基因转移的表达将赋予收缩和舒张性能的长期改善。