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.

摘要： 本提案的总体目标是：1)确定基因组和转录的机制，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；以及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 心房和心室的心肌细胞。这些成果将解决我们在认识上的重大差距 心肌生物钟如何调节心脏关键离子通道的表达以及如何异常 心脏时钟功能是导致心律失常易感性的因素。 调节昼夜节律的机制，即分子钟，几乎存在于人体所有类型的细胞中。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 到目前为止，我们的实验室使用了一种可诱导的心肌细胞特异性小鼠模型来敲打 克隆出核心时钟基因BMal1(ICSΔBMal1)。这些研究表明，心肌钟的扰乱 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，并增加心律失常的易感性。这些研究确定了心肌细胞的关键作用 调节不同离子通道基因家族表达的独立于中央时钟的时钟 这会影响正常兴奋性所需的离子平衡。这个项目的一个目标是利用大规模的 用我们的小鼠模型系统的基因组和转录切割方法来定义昼夜节律依赖的时钟 调控时间基因在心房和心室组织中的表达。 为了解决昼夜节律功能异常的问题，我们实验室使用了不同的昼夜节律干扰模型，例如 随着慢性期的推进或时间限制进食，以测试昼夜节律紊乱和心律失常之间的联系 老鼠模型中的漏洞。我们发现，干扰光线或摄食时间信号足以 诱发正常小鼠心律失常，加速小鼠心源性猝死 遗传性心律失常易感性小鼠模型。这些研究支持了我们的假设，即白天的干扰- 通过环境因素的夜间节律导致心肌钟功能改变，结果是 包括修饰离子通道表达、心脏兴奋性和心律失常易感性。 这项提议的目的是检验以下假设：1)两个心房的分子时钟 而心室肌细胞是指导日常染色质可及性和转录输出所必需的 包括关键离子通道和离子通道调控基因的表达。2)慢性干扰 改变摄食时间的心肌细胞时钟足以引起心脏时钟的失调 导致心脏离子通道表达和电流失衡，导致兴奋性和 心律失常易感性增加。