Circadian clock regulation of myocardial ion channel expression and function

心肌离子通道表达和功能的昼夜节律时钟调节

• 批准号: 10650247
• 负责人: Brian P Delisle
• 金额: $ 57.89万
• 依托单位: UNIVERSITY OF FLORIDA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-09-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10650247
• 关键词: ARNTL gene; ATAC-seq; Acceleration; Action Potentials; Address; Arrhythmia; Behavior; Binding; Biological Models; Cardiac; Cardiac Electrophysiologic Techniques; Cardiac Myocytes; ChIP-seq; Chromatin; Chronic; Chronic Phase; Chronobiology; Circadian Dysregulation; Collection; Cues; Darkness; Data; Data Set; Disease; Electrocardiogram; Electrophysiology (science); Environmental Risk Factor; Family; Gene Expression; Gene Order; Genes; Genetic; Genetic Transcription; Genomics; Goals; Heart; Heart Abnormalities; Heart Atrium; Homeostasis; Hour; Human; Individual; Ion Channel; Knock-out; Knowledge; Life Style; Light; Link; Messenger RNA; Modeling; Molecular; Molecular Target; Mus; Myocardial; Outcome; Outcome Study; Output; Pathologic; Phase; Potassium Channel; Predisposition; Property; Regulation; Regulator Genes; Risk; Risk Factors; Rodent; Role; Series; Testing; Time; Time-restricted feeding; Tissues; Translating; Ventricular; cell type; circadian; circadian pacemaker; design; experimental study; feeding; heart rhythm; insight; ionic balance; modifiable risk; molecular clock; mouse model; patient population; programs; response; sudden cardiac death; suprachiasmatic nucleus; time use; transcriptome sequencing; transcriptomics; translational framework; virtual

Summary: The overall objectives of this proposal are to 1) define the genomic and transcriptomic mechanisms by which the cardiomyocyte clock regulates ion channels that contribute to cardiac excitability; and 2) disrupt the cardiomyocyte clock to link changes in circadian-ordered gene expression with electrophysiological properties of atrial and ventricular cardiomyocytes. The outcomes will address significant gaps in our understanding for how the myocardial circadian clock regulates the expression of key cardiac ion channels and how abnormal cardiac clock function contributes to arrhythmia vulnerability. The mechanism regulating circadian timing, the molecular clock, exists in virtually all cell types in the body. A critical function of the molecular clock is to link time of day with a large-scale transcriptional program to support cellular homeostasis To date, our labs have used an inducible cardiomyocyte specific mouse model to knock out the core clock gene, Bmal1 (iCSΔBmal1). These studies showed that disruption of the myocardial clock is sufficient to decrease ventricular K+ and Na+ channel gene expression, disrupt current levels, disrupt cardiac excitability, and increase arrhythmia susceptibility. These studies establish a critical role for the cardiomyocyte clock, independent of the central clock, in regulating the expression of different families of ion channel genes that impact the ionic balance needed for normal excitability. One goal of this project is to utilize large scale genomic and transcriptomic approaches with our mouse model system to define the circadian clock dependent control of temporal gene expression in both atrial and ventricular tissues. To address abnormal circadian clock function, our lab has used different models of circadian disruption, such as chronic phase advance or time restricted feeding to test links between circadian disruption and arrhythmia vulnerability in mouse models. We have found that disrupting either light or feeding time cues is sufficient to induce pathological changes in cardiac rhythms in normal mice and to accelerate sudden cardiac death in a genetic mouse model of arrhythmia susceptibility. These studies support our premise that disruption of day- night rhythms through environmental factors leads to altered myocardial clock function with outcomes that include modified ion channel expression, cardiac excitability and arrhythmia vulnerability. The aims of this proposal are designed to test the following hypotheses: 1) The molecular clocks in both atrial and ventricular cardiomyocytes are necessary to direct daily chromatin accessibility and transcriptional output including expression of key ion channel and ion channel regulatory genes. 2) Chronic disruption of the cardiomyocyte clock using altered time of feeding is sufficient to cause dysregulation of the cardiac clock resulting in an imbalance in cardiac ion channel expression and currents leading to altered excitability and increased arrhythmia vulnerability.

概括： 该提案的总体目标是 1) 定义基因组和转录组机制，通过这些机制 心肌细胞时钟调节有助于心脏兴奋性的离子通道； 2）扰乱 心肌细胞时钟将昼夜节律基因表达的变化与电生理特性联系起来 心房和心室心肌细胞。结果将解决我们理解上的重大差距 心肌生物钟如何调节关键心脏离子通道的表达以及如何异常 心脏时钟功能导致心律失常的脆弱性。 调节昼夜节律的机制，即分子钟，几乎存在于体内所有细胞类型中。一个 分子钟的关键功能是将一天中的时间与大规模转录程序联系起来以支持 迄今为止，我们的实验室已使用诱导型心肌细胞特异性小鼠模型来敲除 取出核心时钟基因 Bmal1 (iCSΔBmal1)。这些研究表明，心肌时钟的破坏是 足以降低心室 K+ 和 Na+ 通道基因表达、扰乱电流水平、扰乱心脏 兴奋性，增加心律失常的易感性。这些研究确立了心肌细胞的关键作用 时钟，独立于中央时钟，调节不同离子通道基因家族的表达 影响正常兴奋性所需的离子平衡。该项目的目标之一是利用大规模 使用我们的小鼠模型系统的基因组和转录组方法来定义昼夜节律时钟依赖性 控制心房和心室组织中的时间基因表达。 为了解决生物钟功能异常的问题，我们的实验室使用了不同的昼夜节律破坏模型，例如 作为慢性期提前或时间限制喂养来测试昼夜节律紊乱和心律失常之间的联系 小鼠模型中的脆弱性。我们发现，破坏光照或喂食时间线索就足以 引起正常小鼠心律的病理变化并加速心源性猝死 心律失常易感性的遗传小鼠模型。这些研究支持了我们的假设，即白天的干扰 环境因素造成的夜间节律会导致心肌生物钟功能改变，从而导致以下结果： 包括修饰的离子通道表达、心脏兴奋性和心律失常脆弱性。 该提案的目的旨在检验以下假设：1）心房的分子钟 和心室心肌细胞对于指导日常染色质可及性和转录输出是必需的 包括关键离子通道和离子通道调节基因的表达。 2）长期破坏 使用改变喂养时间的心肌细胞时钟足以导致心脏时钟失调 导致心脏离子通道表达和电流不平衡，从而导致兴奋性和 心律失常的脆弱性增加。