Genetic engineering of heart performance

心脏性能的基因工程

• 批准号: 6531858
• 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/6531858
• 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，长期目标是阻止、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小白蛋白（Parv），以及它如何在细胞、器官和有机体水平上直接影响心脏性能。 Parv 是一种小型可溶性蛋白质，属于钙结合蛋白 E-F hand 家族。 Parv 在快肌中自然表达，促进肌肉快速放松。 Parv心里自然不表露。本申请的总体假设是，在心肌中小清蛋白表达的最佳范围内，体外心肌细胞松弛动力学和体内心脏器官舒张功能都将得到增强，同时保留正常收缩功能和β-肾上腺素介导的心脏储备。具体目标是： 目标 1. 确定单个成年心肌细胞中 Parv 基因转移/表达的细胞能力和潜在局限性。子目标 1a：建立 Parv 表达阈值和最佳表达范围，以获得改善的心肌细胞松弛功能。子目标 1 b：确定表达 Parv 的心肌细胞中的力-频率关系。子目标 1c：确定并比较 Parv 和钙泵-SERCA-2a 基因转移后 β-肾上腺素能刺激对肌细胞收缩的影响。目标 2. 确定 Parv 心脏定向表达对转基因小鼠整个器官和机体水平的影响。子目标 2a：产生在心脏异位表达低、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：在离体心脏中存在/不存在肾上腺素能刺激的情况下，建立不同起搏速率下 Parv 表达与表现之间的关系。子目标 2d：利用无线电遥测技术在完全清醒且不受束缚的小鼠中确定 Parv 表达对体内心血管功能的长期影响。 Parv 中等表达时，要检验的假设是心脏收缩功能会增强；对于非常高的 Parv 表达（>0.4 mM），心血管收缩功能将会减弱，并且会因运动而加剧。总之，这些综合的具体目标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 Parv 在心脏中表达的潜在治疗能力和局限性。