Calcineurin-Mediated Regulation of Cardiac Ca2+ Channel

钙调神经磷酸酶介导的心脏 Ca2+ 通道调节

基本信息

批准号：
7256489
负责人：
JOSEPH A HILL
金额：
$ 33.49万
依托单位：
UT SOUTHWESTERN MEDICAL CENTER
依托单位国家：
美国
项目类别：
财政年份：
2005
资助国家：
美国
起止时间：
2005-08-01 至 2010-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7256489
关键词：
Action Potentials Acute Address Adenovirus Vector Adult Binding Calcineurin Cardiac Cardiac Myocytes Chest Complex Consensus Sequence Cytoplasmic Protein Data Docking Failure Functional disorder Gene Expression Genes Genetic Transcription Genomics Heart Heart Diseases Heart Hypertrophy Homeostasis Hypertrophy Indium Localized Macromolecular Complexes Mediating Mediator of activation protein Messenger RNA Modeling Molecular Morphology Mus Muscle Cells Mutate Mutation NF-AT Numbers Pathogenesis Pathway interactions Phosphorylation Site Promoter Regions Protein phosphatase Regulation Reporter Reporting Role Ryanodine Receptor Calcium Release Channel Series Signal Transduction Site System Testing Transcriptional Activation Transfection Transgenic Mice Up-Regulation Ventricular Work base clinically relevant in vivo in vivo Model myocyte-specific enhancer-binding factor 2 nuclear factors of activated T-cells pressure reconstitution research study stem

项目摘要

DESCRIPTION (provided by applicant): Perturbation of intracellular Ca2+ signaling and prolongation of the action potential accompany many forms of heart disease and contribute to the pathogenesis of cardiac hypertrophy and failure. The L-type Ca2+ channel is the major mediator of Ca2+ influx into cardiomyocytes and an important determinant of action potential morphology. The role of the L-type channel - the proximal element in Ca2+ signaling - in the pathophysiology of cardiac hypertrophy is poorly characterized. Calcineurin is a cytoplasmic protein phosphatase that mediates hypertrophic signaling in many models of cardiac hypertrophy including our own model of aortic banding in mice. We have reported that activity and abundance of the L-type Ca2+ channel are altered in pressure-overload cardiac hypertrophy through calcineurin-dependent pathways. In this application, we propose to elucidate the underlying mechanisms. This proposal is based on the hypotheses that calcineurin is a regulatory component of the L-type Ca2+ channel complex in cardiac myocytes. We further hypothesize that calcineurin-dependent mechanisms regulate Ca2+ channel function both directly and through altered gene expression. Finally, we hypothesize that these changes - post-translational and transcriptional - contribute to hypertrophic prolongation of the ventricular action potential and consequent arrhythmogenesis. We have collected evidence that calcineurin is a component of the L-type channel macromolecular complex in heart, a finding which will be confirmed and extended in Aim 1. In Aim 2, we will determine whether calcineurin regulates Ca2+ channel function using suppression and heterologous reconstitution strategies. In Aim 3, we will pursue our observation that calcineurin, in addition to regulating channel activity, also regulates transcription of alpha1c, the channel pore-forming subunit. We have cloned a large, 5' fragment of the alpha1c gene and generated reporter constructs to use in transient transfection experiments. We have also generated "alpha1c reporter" transgenic mice, which we will use to decipher pathways governing a1c expression in vivo. In Aim 4, we will determine whether the mechanisms of calcineurin regulation of Ca2+ channel expression and function examined in Aims 1-3 occur in a clinically relevant, in vivo model of hypertrophy.

描述（由申请人提供）：细胞内Ca2+信号传导的扰动和动作电位的延长伴随着许多形式的心脏病，并有助于心脏肥大和失败的发病机理。 L型Ca2+通道是Ca2+涌入心肌细胞的主要介体，也是动作电位形态的重要决定因素。 L型通道的作用 - Ca2+信号传导中的近端元素 - 在心脏肥大的病理生理学中的作用很差。钙调蛋白是一种细胞质蛋白磷酸酶，在许多心脏肥大模型中介导肥厚的信号传导，包括我们自己的小鼠主动脉谱带模型。我们报告说，通过钙调蛋白依赖性途径，L型Ca2+通道的活性和丰度改变了压力过载的心脏肥大。在此应用中，我们建议阐明潜在的机制。该建议基于钙调神经磷酸酶是心肌细胞中L型Ca2+通道复合物的调节成分的假设。我们进一步假设钙调蛋白依赖性机制可以直接和通过改变的基因表达来调节Ca2+通道功能。最后，我们假设这些变化 - 翻译后和转录 - 有助于心室作用潜力的肥厚型延长以及随之而来的心律失常发生。我们已经收集了证据，表明钙调神经蛋白是心脏中L型通道大分子复合物的组成部分，这一发现将在AIM 1中进行确认并扩展。在AIM 2中，我们将确定钙调神经素是否使用抑制和异源重构策略来调节Ca2+通道功能。在AIM 3中，我们将观察到钙调神经磷酸酶外，除了调节通道活性外，还调节α1c的转录，即通道孔形成亚基。我们克隆了一个大的5'α1c基因片段，并生成了用于瞬态转染实验的报告构建体。我们还生成了“ alpha1c报告基因”转基因小鼠，我们将使用该小鼠破译在体内控制A1c表达的途径。在AIM 4中，我们将确定在AIMS 1-3中检查的Ca2+通道表达和功能的钙调蛋白调节的机制是否发生在临床相关的体内肥大模型中。