Post-Transcriptional Regulation of Myocardial Sodium Channels

心肌钠通道的转录后调节

基本信息

批准号：
10660961
负责人：
JEANNE M. NERBONNE
金额：
$ 57.15万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-07-01 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10660961
关键词：
Action Potentials Adult Animal Model Anti-Arrhythmia Agents Arrhythmia Binding Binding Sites Biophysics Brugada syndrome Calmodulin Cardiac Cardiomyopathies Cells Closure by clamp Data Dependence Disease Electrophysiology (science)Experimental Designs FGF12 gene Fibroblast Growth Factor Fluorometry Generations Goals Heart Heart Atrium Heart Diseases Human In Vitro Inherited Intervention Ion Channel Kinetics Life Link Macromolecular Complexes Maintenance Mediating Membrane Metabolic Diseases Modeling Molecular Molecular Genetics Multiprotein Complexes Mus Muscle Cells Myocardial Optics Patients Physiological Play Post-Transcriptional Regulation Probability Property Proteins Quantitative Reverse Transcriptase PCR Regulation Reporting Research Risk Rodent Role Shapes Sodium Sodium Channel Sudden Death Temperature Testing Variant cell type experimental study genetic approach heart rhythm in silico in vivo indium arsenide insight multidisciplinary new therapeutic target pharmacologic posttranscriptional programs sudden cardiac death therapeutic target transcriptome sequencing voltage voltage clamp

项目摘要

Voltage-gated Na+ (Nav) channels play key roles in action potential generation and in controlling action potential durations and propagation in the mammalian heart, and these channels are critical for the maintenance of normal cardiac rhythms. Changes in Nav channel expression and properties are prevalent in inherited and acquired cardiac diseases, and these changes can have profound pathophysiological consequences, including increasing the risk of potentially life-threatening cardiac arrhythmias. Although it seems generally accepted that native myocardial Nav channels function in macromolecular protein complexes, comprising the pore-forming Nav1.5 subunit and multiple intracellular and transmembrane accessory subunits, the physiological roles of accessory subunits in regulating Nav channel function and how these roles are altered with myocardial disease are poorly understood. This new collaborative research program is focused on defining the post-transcriptional mechanisms involved in the physiological regulation and pathophysiological dysregulation of myocardial Nav1.5-encoded channels by intracellular Nav channel accessory subunits. A multifaceted experimental strategy has been developed to define the molecular and cellular mechanisms underlying the regulatory effects of intracellular Fibroblast Growth Factor 12B, iFGF12B, the main iFGF variant expressed in non-diseased human heart, on the gating of Nav1.5-encoded Nav channels (aim #1), and test the hypothesis that iFGF12A, which is upregulated in failing human heart, has distinct effects on the biophysical and pharmacological properties of cardiac Nav1.5-encoded channels (aim #2). Additional experiments will test the hypothesis that another intracellular accessory subunit, calmodulin, CaM, which binds to the C terminus of Nav1.5 near the iFGF binding site, modulates iFGF12B/iFGF12A- mediated effects on Nav1.5-encoded channel gating (aim #3). We will also create molecularly-detailed Nav channel gating models that include Nav1.5 regulation by iFGF12A, iFGF12B and CaM and will use these models to delineate the impact of iFGF12-mediated regulation of native Nav currents on myocyte electrophysiology. These studies will provide fundamentally important new insights into the molecular and cellular mechanisms underlying iFGF12-mediated regulation of myocardial Nav1.5-encoded channels and into the physiological roles of iFGF12 in the dynamic regulation of cardiac excitability. These insights will inform efforts to explore the potential of iFGFs and of iFGF-Nav1.5 interactions as new therapeutic targets to modulate Nav channel functioning in inherited and acquired cardiac rhythm disorders.

电压门控 Na+ (Nav) 通道在动作电位生成和控制动作中发挥关键作用哺乳动物心脏中的潜在持续时间和传播，这些通道对于维持正常的心律。导航通道表达式和属性的变化普遍存在于遗传性和获得性心脏病，这些变化可能具有深远的病理生理学意义后果，包括增加潜在危及生命的心律失常的风险。虽然它似乎普遍认为天然心肌 Nav 通道在大分子蛋白中发挥作用复合物，包含成孔 Nav1.5 亚基和多个细胞内和跨膜辅助亚基、辅助亚基在调节 Nav 通道功能中的生理作用以及如何这些作用会随着心肌疾病而改变，但人们对此知之甚少。这项新的合作研究该计划的重点是定义涉及生理调节和转录后机制细胞内 Nav 通道对心肌 Nav1.5 编码通道的病理生理失调附属亚基。已经开发了多方面的实验策略来定义分子和细胞内成纤维细胞生长因子 12B、iFGF12B、在未患病人类心脏中表达的主要 iFGF 变体，位于 Nav1.5 编码的 Nav 的门控上通道（目标#1），并检验 iFGF12A（在人类心脏衰竭时上调）的假设对心脏 Nav1.5 编码通道的生物物理和药理学特性有明显影响（目标＃2）。额外的实验将检验另一个细胞内辅助亚基钙调蛋白的假设 CaM 与 iFGF 结合位点附近的 Nav1.5 C 末端结合，调节 iFGF12B/iFGF12A- 对 Nav1.5 编码通道门控的介导效应（目标#3）。我们还将创建分子详细的导航通道门控模型，包括 iFGF12A、iFGF12B 和 CaM 的 Nav1.5 调节，并将使用这些模型描述 iFGF12 介导的原生 Nav 电流调节对肌细胞电生理学的影响。这些研究将为分子和细胞机制提供根本上重要的新见解 iFGF12 介导的心肌 Nav1.5 编码通道的潜在调节并进入生理学 iFGF12 在心脏兴奋性动态调节中的作用。这些见解将为探索工作提供信息 iFGF 和 iFGF-Nav1.5 相互作用作为调节 Nav 通道新治疗靶点的潜力在遗传性和获得性心律失常中发挥作用。