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.

电压门控的NA+（NAV）频道在动作潜力生成和控制动作中扮演关键角色哺乳动物心脏的潜在持续时间和传播，这些渠道对维持正常心律。 NAV通道表达和属性的变化在遗传和获得的心脏疾病，这些变化可能具有深远的病理生理后果，包括增加潜在威胁生命心律不齐的风险。虽然是似乎普遍认为，天然心肌NAV通道在大分子蛋白中的功能复合物，包括形成孔的NAV1.5亚基以及多个细胞内和跨膜附件亚基，附件亚基在调节NAV通道功能中的生理作用以及如何这些角色因心肌疾病而改变。这项新的合作研究计划的重点是定义与生理调节有关的转录后机制心肌NAV 1.5的病理生理失调通过细胞内NAV通道编码的通道附件亚基。已经开发了一种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的调节作用的基础机制 IFGF的主要IFGF变体以非戒断的人心脏表示，在NAV1.5编码的NAV的门控上渠道（AIM＃1），并检验以下假设：在失败的人心中被上调的IFGF12A具有对心脏NAV1.5编码通道的生物物理和药理特性的明显影响（AIM ＃2）。其他实验将检验以下假设：另一个细胞内附件亚基钙调蛋白， CAM与IFGF结合位点附近的NAV1.5的C末端结合，调节IFGF12B/IFGF12A- 介导对NAV1.5编码的通道门控的影响（AIM＃3）。我们还将创建分子详细信息频道门控模型，其中包括IFGF12A，IFGF12B和CAM的NAV1.5法规，并将使用这些模型描绘了IFGF12介导的天然NAV电流调节对心肌细胞电生理学的影响。这些研究将对分子和细胞机制提供根本重要的新见解基础IFGF12介导的心肌NAV1.5编码通道的调节并进入生理 IFGF12在心脏兴奋性动态调节中的作用。这些见解将为探索 IFGFS和IFGF-NAV1.5相互作用的潜力作为调节NAV通道的新治疗目标在遗传和获得的心律疾病中发挥作用。