Genetic engineering of heart performance

心脏性能的基因工程

• 批准号: 6952291
• 负责人: JOSEPH Mark METZGER
• 金额: $ 35.83万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-07-01 至 2006-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6952291
• 关键词: Adenoviridae; beta adrenergic agent; beta adrenergic receptor; calcium binding protein; calcium transporting ATPase; cardiac myocytes; cardiovascular disorder prevention; cardiovascular function; gene expression; genetic manipulation; genetic transduction; genetically modified animals; heart conduction system; hemodynamics; laboratory mouse; laboratory rat; muscle relaxation; phosphorylation; telemetry; tissue /cell culture; tissue /cell preparation

DESCRIPTION (provided by applicant): The aim of this proposal is to enhance cardiac function by genetic engineering, with the long-term goal of halting, reversing or preventing contractile dysfunction in diseased myocardium. The proposal is focused on the calcium binding protein parvalbumin (Parv), and how it directly affects cardiac performance at the cellular, organ and organismal levels. Parv is a small, soluble protein that belongs to the E-F hand family of calcium binding proteins. Parv is naturally expressed in fast-twitch muscle where it facilitates rapid muscular relaxation. Parv is not naturally expressed in the heart. The overarching hypothesis of this application is that over an optimal range of parvalbumin expression in cardiac muscle, both cardiac myocyte relaxation kinetics in vitro, and heart organ diastolic function in vivo will be enhanced while retaining both normal systolic function and beta-adrenergic-mediated cardiac reserve. The Specific Aims are: Aim 1. To define the cellular capabilities and potential limitations of Parv gene transfer/expression in single adult cardiac myocytes. Sub Aim 1 a: To establish the Parv expression threshold and optimal expression range for obtaining improved relaxation function in cardiac myocytes. Sub Aim 1 b: To determine the force-frequency relationship in Parv expressing cardiac myocytes. Sub Aim 1 c: To determine and compare the effects of beta-adrenergic stimulation on the contraction in myocytes after Parv and calcium pump-SERCA-2a gene transfer. Aim 2. To determine the effects of cardiac-directed expression of Parv at the whole organ and organismal levels in transgenic mice. Sub Aim 2a: To generate transgenic mouse lines expressing low, moderate, and high levels of Parv ectopically in the heart. Sub Aim 2b: To establish Parv expression-dependent effects on cardiac hemodynamic function in vivo. Sub Aim 2c: To establish the relationship between Parv expression and performance at differing pacing rates, and in the presence/absence of adrenergic stimulation in the isolated heart. Sub Aim 2d: To establish the long-term effects of Parv expression on in vivo cardiovascular function using radiotelemetry in fully conscious and untethered mice. At moderate Parv expression, the hypothesis to be tested is that systolic heart function will be enhanced; for very high Parv expression (>0.4 mM), systolic cardiovascular function will diminish, and will be exacerbated by exercise. Together, these integrated Specific Aims and hypotheses provide the necessary basic biological foundation on which to fully assess the potential therapeutic capabilities and limitations of Parv expression in the heart.

描述（由申请人提供）：本提案的目的是通过基因工程增强心脏功能，长期目标是停止、逆转或预防患病心肌的收缩功能障碍。该提案的重点是钙结合蛋白parvalbumin（Parv），以及它如何直接影响细胞，器官和生物体水平的心脏性能。Parv是一种小的可溶性蛋白，属于钙结合蛋白的E-F手家族。Parv在快速收缩肌肉中自然表达，促进快速肌肉放松。Parv不是自然地在心中表达。本申请的首要假设是，在心肌中小白蛋白表达的最佳范围内，体外心肌细胞舒张动力学和体内心脏器官舒张功能都将增强，同时保持正常收缩功能和β-肾上腺素能介导的心脏储备。具体目标是：目标1。明确Parv基因在单个成年心肌细胞中转移/表达的细胞能力和潜在限制。子目标1a：建立Parv表达阈值和最佳表达范围，以改善心肌细胞的舒张功能。子目标1 B：确定Parv表达心肌细胞中的力-频率关系。子目标1c：比较β-肾上腺素能刺激对Parv和钙泵-SERCA-2a基因转染后心肌细胞收缩的影响。目标2.确定转基因小鼠心脏定向表达Parv在整个器官和组织水平的影响。子目标2a：生成心脏异位表达低、中和高水平Parv的转基因小鼠系。子目标2b：确定Parv表达依赖性对体内心脏血流动力学功能的影响。子目标2c：在离体心脏中，在存在/不存在肾上腺素能刺激的情况下，确定不同起搏频率下Parv表达与性能之间的关系。子目标2d：在完全清醒和未栓系小鼠中，使用无线电遥测确定Parv表达对体内心血管功能的长期影响。在中等Parv表达时，待检验的假设是收缩期心脏功能将增强;对于非常高的Parv表达（> 0.4mM），收缩期心血管功能将减弱，并且将因运动而加剧。总之，这些整合的特定目的和假设提供了必要的基本生物学基础，在此基础上充分评估心脏中Parv表达的潜在治疗能力和局限性。