Mechanisms of Long-term Cardiac Ion Channel Regulation

心脏离子通道的长期调节机制

• 批准号: 6673929
• 负责人: Jonathan Satin
• 金额: $ 36.75万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-07-15 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6673929
• 关键词: G protein; atrial fibrillation; biological signal transduction; calcium channel; calcium ion; cardiac myocytes; cell membrane; confocal scanning microscopy; electrophysiology; heart failure; heart function; laboratory mouse; laboratory rat; polymerase chain reaction; protein binding; protein kinase A; protein protein interaction; recombinant proteins; sarcolemma; second messengers; telemetry; voltage gated channel; western blottings

DESCRIPTION (provided by applicant): Heart failure (HF) and atrial fibrillation (AF) represent two of the most prevalent heart diseases in the U.S. In moderate to severe HF and in AF numerous phenotypic changes occur including a reduction of voltage-gated calcium channel current density. Changes in Ca channel expression may have far-reaching effects on heart function due to their central role in excitation contraction coupling. Also, Ca channels have been implicated in excitation-transcription coupling. Thus alterations of Ca channel expression in the heart can also impact on disease progression. The principal voltage-gated Ca channel in the heart (CaV1.2) is extensively studied in the realm of its biophysical characteristics and second messenger modulation. However, very sparse information is available regarding longer term regulation of Ca channel expression. In this proposal we introduce a novel mechanistic hypothesis governing the functional expression of cardiac Ca channels in the sarcolemma of cardiac myocytes. In our preliminary data we show evidence for a ras-related monomeric G-protein interaction with the CaV1.2 accessory subunit CaVb2. We propose to test the global hypothesis that G-protein interaction with CaVb subunits reduces Ca channel current density by competing for CaV1.2 binding. Moreover, our preliminary data shows strong evidence that this is a dynamic process that is modulated by chronic PKA activity. There are four specific aims that guide our experimental design: Aim 1 will characterize the time course and sub-cellular localization of nascent G-protein and CaVb complexes. Aim 2 will characterize the intracellular second messenger modulation of G-protein-CaVb regulation of Ca channel current expression. Aim 3 will characterize the modulation of Ca channel current and G-protein modulation in native cells. Aim 4 will characterize the function of these G-proteins in heart function. These aims encompass approaches ranging from investigations of a purely molecular nature (protein-protein interactions), to in vitro model systems (heterologous expression of recombinant proteins), to native cell systems (primary isolates and cultures of heart cells), to the impact of a single class of G-proteins on tissue level heart function. This proposal may identify a novel class of therapeutic targets for alleviation of heart dysfunction in HF and AF.

描述（由申请人提供）：心力衰竭（HF）和心房颤动（AF）代表美国最普遍的心脏病中的两种，中度至重度HF，在AF中发生了许多表型变化，包括降低电压门控钙通道电流电流密度。 CA通道表达的变化可能会对心脏功能产生深远的影响，因为它们在激发收缩耦合中的核心作用。同样，CA通道也与激发转录耦合有关。因此，心脏中CA通道表达的改变也会影响疾病进展。在其生物物理特性和第二信使调制的领域中，对心脏（CAV1.2）的主要电压门控通道进行了广泛的研究。但是，有关CA通道表达的长期调节的非常稀疏的信息。在此提案中，我们引入了一个新的机械假设，该假设管理心肌细胞肌细胞中心脏CA通道的功能表达。在我们的初步数据中，我们显示了与RAS相关的单体G蛋白与CAV1.2附件亚基CAVB2的相互作用的证据。我们建议测试全球假设，即通过竞争CAV1.2结合，G蛋白与CAVB亚基的相互作用可降低CA通道电流密度。此外，我们的初步数据表明，这是一个由慢性PKA活性调节的动态过程。有四个指导我们的实验设计的特定目标：AIM 1将表征新生G蛋白和CAVB复合物的时间过程和细胞亚细胞定位。 AIM 2将表征CA通道电流表达的G蛋白-CAVB调节的细胞内第二信使调制。 AIM 3将表征天然细胞中CA通道电流和G蛋白调制的调节。 AIM 4将表征这些G蛋白在心脏功能中的功能。这些目的包括从纯粹分子性质（蛋白质 - 蛋白质相互作用）到体外模型系统（重组蛋白的异源表达）到天然细胞系统（心脏细胞的初级分离株和心脏细胞培养）到单个类别G蛋白对组织水平心脏功能的影响。该提案可以确定一种新型的治疗靶标，以减轻HF和AF中心脏功能障碍。