Phosphorylation and gating of cardiac connexin channels

心脏连接蛋白通道的磷酸化和门控

• 批准号: 9078759
• 负责人: JANIS M BURT
• 金额: $ 39.57万
• 依托单位: UNIVERSITY OF ARIZONA
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-04-01 至 2020-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9078759
• 关键词: Accounting; Acute; Address; Adult; Affinity; Alanine; Anti-Arrhythmia Agents; Arrhythmia; Aspartate; Back; Behavior; Beryllium; Blood flow; Cardiac; Cardiac Myocytes; Cells; Cessation of life; Communication; Connexin 43; Connexins; Coupling; Cyclic AMP-Dependent Protein Kinases; Data; Development; Disease; Event; Failure; Global Change; Goals; Heart; Heart Atrium; Heart Diseases; Heterogeneity; Implantable Defibrillators; Injury; Intercalated disc; Knowledge; Lead; Ligands; Link; Mediating; Methods; Modeling; Molecular; Muscle Cells; Output; Pathway interactions; Pattern; Periodicity; Permeability; Phosphorylation; Physiological; Property; Protein Dephosphorylation; Proteins; Publishing; Rattus; Regulation; Signal Transduction; Site; Staging; Structure; Tachycardia; Testing; Therapeutic Uses; Tissues; Uncertainty; Ventricular; Ventricular Fibrillation; Ventricular Tachycardia; base; calmodulin-dependent protein kinase II; coronary artery occlusion; design; gap junction channel; heart function; improved; injured; insight; insulinoma; intercellular communication; meetings; mutant; novel therapeutics; particle; peptidomimetics; preconditioning; prevent; public health relevance; receptor; sudden cardiac death; targeted treatment; therapy design; tool; voltage; voltage clamp

 DESCRIPTION (provided by applicant): Gap junction channels (GJCh) comprise the pathway for intercellular propagation of the electrical signals responsible for coordinated activation of cardiac contraction; heterogeneity and failure of GJCh function lead to heterogeneous slowing of conduction and consequent micro- or macro-reentry circuits that set the stage for tachycardia and fibrillation in the atria and ventricles. Heterogeneity and failure of GJCh function reflect acute, phosphorylation-dependent regulation of GJCh gating and conductance. This application focuses on the GJCh gating and conductance changes that are antiarrhythmic (preconditioning) and proarrhythmic, contributing to sudden cardiac death. The long-term goals of the project are to: 1) understand the mechanisms underlying phosphorylation-dependent regulation of Cx43 GJCh and hemichannel (HCh) function, and 2) develop from that knowledge peptidomimetics that will target or induce specific functional properties of Cx43 channels that will preserve cardiac rhythmicity and prevent irreversible injury. Two key issues limit our ability to implement Cx43 based therapies. First, we do not understand the consequences of differential Cx43 phosphorylation on GJCh function. Second, the impact of heterogeneous Cx43 phosphorylation on impulse propagation in the heart is unknown. Because these issues cannot be addressed in pairs of adult ventricular myocytes (due to heterogeneity of Cx43 phosphorylation state and the large number of functioning GJChs that preclude study of gating and single channel behavior by the necessary whole-cell voltage clamp methods), we address our aims using site-mutants of Cx43 that mimic the phosphorylation state of Cx43 in normally functioning, preconditioned and injured heart. We express these Cx43 site mutants in Cx-deficient rat insulinoma cells, Cx43-deficient cardiomyocytes, and wild-type cardiomyocytes, where their gating, conductance and antiarrhythmic properties can be studied. The results of our studies will guide design and testing of function- specific, high-affinity peptidomimetics to interfere with or mimic the interactions tht underlie anti-arrhythmic GJCh and HCh function. The proposed combination of molecular, structural and functional approaches can be expected to provide new mechanistic insight on regulation of the dynamic function of Cx43 GJChs as they support the extraordinary dynamic range of cardiac function. In addition, we expect to develop Cx43- and function-specific, experimentally and therapeutically useful tools that will protect coordinated function of the heart despite ongoing disease and pharmacologic therapies.

 描述(申请人提供)：缝隙连接通道(GJCH)包括负责协调激活心脏收缩的电信号在细胞间传播的途径；GJCH功能的异质性和故障导致传导异质性减慢，从而导致微或大折返电路，从而为心房和心室的心动过速和纤颤奠定基础。GJCH功能的异质性和失效反映了GJCH门控和电导的急性、磷酸化依赖的调节。这一应用侧重于GJCH门控和电导的变化，这些变化是抗心律失常(预适应)和致心律失常的，导致心源性猝死。该项目的长期目标是：1)了解依赖磷酸化的Cx43 GJCH和半通道(HCH)功能调节的机制，以及2)在此基础上发展模拟肽学，靶向或诱导Cx43通道的特定功能特性，以保持心律节律性和防止不可逆转的损伤。两个关键问题限制了我们实施基于Cx43的疗法的能力。首先，我们不知道Cx43的不同磷酸化对GJCH功能的影响。其次，异质性Cx43磷酸化对心脏中脉冲传播的影响尚不清楚。由于这些问题不能在成对的成人心室肌细胞中解决(由于Cx43磷酸化状态的异质性和大量功能的GJChs，这使得通过必要的全细胞电压钳方法来研究门控和单通道行为)，我们使用Cx43的位点突变体来解决我们的目标，它模仿正常功能、预适应和损伤的心脏中Cx43的磷酸化状态。我们在Cx缺失的大鼠胰岛素瘤细胞、Cx43缺失的心肌细胞和野生型心肌细胞中表达了这些Cx43位点突变，在这些细胞中可以研究它们的门控、电导和抗心律失常的特性。我们的研究结果将指导设计和测试功能特异的、高亲和力的多肽仿制药，以干扰或模拟抗心律失常GJCH和HCH功能的相互作用。所提出的分子、结构和功能方法的结合有望为Cx43 GJChs的动态功能调节提供新的机械学见解，因为它们支持心脏功能的非凡动态范围。此外，我们希望开发针对Cx43和功能的、实验和治疗有用的工具，以保护心脏的协调功能 尽管疾病和药物治疗仍在进行。