Altered Cell-Cell Coupling in Arrhythmogenic Cardiomyopathy

项目总结/摘要 本项目的目标是阐明致肿瘤性细胞间隙连接重塑的机制。 心肌病（ACM）是年轻人，特别是运动员猝死的主要原因。间隙连接 重塑发生在ACM的早期，远早于纤维脂肪瘢痕组织和收缩功能障碍的发展。 心律失常经常发生在这个所谓的“隐蔽期”，似乎是通过相互作用而产生的 细胞间电耦合改变与INa和IK1降低之间的关系。在这里，我们建议研究定义，在一个 以前从未达到的细节水平，间隙连接重塑如何在这个高度致瘤的人类中发生， 心脏病以及它如何导致猝死。此外，我们有一个小分子， ACM中的连接重塑。因此，我们不仅要明确ACM间隙连接重塑的机制， 而且还将定义最终可用于患者的基于机制的治疗的作用模式。 在拟议的研究中，我们将使用最先进的方法来严格量化Cx43的变化。 在闰盘的表达和测量表达ACM的心室肌细胞中的细胞-细胞电导。 引起桥粒突变（这种测量。我们将描述脉冲传播的变化， 在精确图案化的组织制备物和完整的成年小鼠心脏中的亚细胞水平分辨率 使用忠实地再现患者中所见ACM疾病表型的多种模型。我们将使用 强大的计算工具来定义减少的细胞-细胞电耦合和减少的细胞间电耦合之间的相互作用。 INa和IK1电流密度，并精确确定其各自对传导异常的贡献 和胚胎发生。我们将与权威人士Robin Shaw合作进行详细研究 在连接蛋白运输，以确定负责ACM间隙连接重塑的分子机制。我们 将定义基于EB1的Cx43正向贩运在ACM中的作用，并调查Cx43变化的作用。 磷酸化和内化。我们还将阐明异常的分子机制， GSK 3 β/APC/Axin复合物易位到闰盘干扰ACM中Cx43的运输。 最终目标是开发新的方法，通过纠正贩运来预防ACM猝死 这种缺陷似乎是这种疾病谱中致命性节律紊乱的根源。

Project Summary/Abstract The goal of this project is to elucidate mechanisms responsible for gap junction remodeling in arrhythmogenic cardiomyopathy (ACM), a leading cause of sudden death in the young and especially in athletes. Gap junction remodeling occurs early in ACM, well before development of fibro-fatty scar tissue and contractile dysfunction. Arrhythmias occur frequently during this so-called “concealed phase” and appear to arise through interactions between altered cell-cell electrical coupling and reduced INa and IK1. Here, we propose studies to define, at a level of detail never before achieved, how gap junction remodeling occurs in this highly arrhythmogenic human heart disease and how it promotes sudden death. Moreover, we have a small molecule that reverses gap junction remodeling in ACM. Thus, we will not only define the mechanism of gap junction remodeling in ACM, but will also define the mode of action of a mechanism-based therapy that may eventually be used in patients. In the proposed research, we will use state-of-the-art methods to rigorously quantify changes in Cx43 expression at intercalated discs and measure cell-cell conductance in ventricular myocytes expressing ACM- causing desmosomal mutations (such measurements. We will characterize changes in impulse propagation at a subcellular level of resolution in precisely patterned tissue preparations and in intact adult mouse hearts using multiple models that faithfully recapitulate the ACM disease phenotype seen in patients. We will use powerful computational tools to define interactions between reduced cell-cell electrical coupling and reduced INa and IK1current densities, and precisely determine their individual contributions to conduction abnormalities and arrhythmogenesis. We will perform detailed studies in collaboration with Robin Shaw, a leading authority in connexin trafficking, to define molecular mechanisms responsible for gap junction remodeling in ACM. We will define the role of EB1-based forward Cx43 trafficking in ACM, and investigate the role of changes in Cx43 phosphorylation and internalization. We will also elucidate molecular mechanisms by which abnormal translocation of the GSK3β/APC/Axin complex to the intercalated disc interferes with Cx43 trafficking in ACM. The ultimate objective is to develop new ways to prevent sudden death in ACM by correcting the trafficking defect that appears to be at the root of lethal rhythm disorders in this disease spectrum.