Administrative Core

该计划项目的总体目标是确定引发致命疾病的细胞和分子诱因 心律失常，并确定治疗它们的新的分子靶向治疗策略。这个 中心假说是心源性猝死(SCD)可由分子复合体的破坏引起 在正常心脏中，这些过程是细胞活动平衡调节的基础，而且 细胞内钙稳态的改变在触发由此产生的心律失常活动中起关键作用。它 因此，这个项目的基本假设是，为了理解事件的机械基础 在SCD的基础上，需要一种综合的方法来考虑离子通道分子的变体 协调细胞内(方案1)和表面(肌膜)(方案2)离子功能的复合体 以及细胞内钙调节所发挥的关键和核心作用(项目3)。一个关键方面 该计划的核心是动物核心B，它将维护和提供遗传小鼠模型给每个 三个PI。本项目(项目1)侧重于阐明2型ryanodine调控中的缺陷 受体(RyR2)/肌质网钙释放通道，这是心脏兴奋收缩(EC)偶联所必需的。 我们建议检验这一假说，即通过RyR2缺陷的舒张期SR钙“泄漏”可以作为触发 导致心源性猝死(SCD)的致命性心律失常。由此产生了一个新的主题 该项目的概念是，存在编码蛋白质的基因，这些蛋白质对SCD具有“保护性”。在.期间 在该项目的前一个资助期，申请人发现了运动诱导的患者的RyR2缺陷。 SCD：与稳定亚基结合亲和力降低的“泄漏”RyR2通道 钙稳定蛋白2(FKBP12.6)。这一观察结果直接导致了一种新的潜在疗法的开发 对于SCD，RyCal(JTV-S36，这是JTV-519的衍生产品，没有HERG和L类型的频道阻塞 活性)，代表了一类新的细胞内钙通道稳定剂，可防止运动诱导 小鼠模型中的SCD。在前一次供资期间，申请人确定了磷酸二酯酶 PDE4D3作为RyR2大分子信号复合体的新成分和初步数据， 提示RyR2复合体中的PDE4D3可能对SCD具有保护作用 因为PDE4D3缺乏的小鼠更容易发生运动性SCD。此外，一只老鼠 RyR2-S2808A被设计成表达不能被PKA磷酸化的RyR2通道，受到保护 抗罗利普兰抑制PDE4所致的SCD。与项目2的绩效指标密切互动(R. KASS-电压门控离子通道)和项目3(W.J.莱德尔-钙信号)增强了每个 拟议的目标详述如下。因此，这项工作有可能确定 分子水平上的心脏性猝死(SCD)，并基于以下方面开发人类的治疗策略 特定的分子和机理模型。

The overall goal of this program project is to identify the cellular and molecular triggers that initiate fatal cardiac arrhythmias and to determine novel molecular-targeted therapeutic strategies to treat them. The central hypothesis is that sudden cardiac death (SCD) can be caused by disruption of molecular complexes and processes that, in normal hearts, underlie balanced regulation of cellular activity and furthermore that altered cellular calcium (Ca) homeostasis plays a critical role in triggering the resulting arrhythmic activity. It is thus the fundamental assumption of this program that, to understand the mechanistic basis of the events that underlie SCD, an integrative approach is necessary that considers variants of ion channel molecular complexes that coordinate the function of intracellular (Project 1) and surface (sarcolemmal) (Project 2) ion channels as well as a critical and central role played by intracellular Ca regulation (Project 3). A key aspect of this Program is the Animal Core B that will maintain and provide genetic mouse models to each of the three PIs. This project (Project 1) focuses on elucidating defects in the regulation of type 2 ryanodine receptor (RyR2)/SR Ca release channel, which is required for cardiac excitation-contraction (EC) coupling. We propose to test the hypothesis that a diastolic SR Ca "leak" via defective RyR2 can serve as triggers for fatal cardiac arrhythmias which cause sudden cardiac death (SCD). A new theme that has emerged from this project is the concept that there are genes that encode proteins which are "protective" against SCD. During the previous funding period of this project the applicant identified a defect in RyR2 in patients with exercise-induced SCD: "leaky" RyR2 channels that exhibit decreased binding affinity for the stabilizing subunit calstabin2 (FKBP12.6). This observation has directly lead to the development of a novel potential therapy for SCD, RyCal (JTV-S36, which is a JTV-519 derivative without HERG and L-type channel blocking activities), representing a new class of intracellular calcium channel stabilizers that prevent exercise-induced SCD in mouse models. During the previous funding period the applicant identified the phosphodiesterase PDE4D3 as a novel component of the RyR2 macromolecular signaling complex and preliminary data, presented in this proposal, suggest that PDE4D3 in the RyR2 complex may be "protective" against SCD because mice that are deficient in PDE4D3 are predisposed to exercise-induced SCD. Moreover, a mouse engineered to express an RyR2 channel that cannot be PKA phosphorylated, RyR2-S2808A, is protected against SCD induced by inhibition of PDE4 with rolipram. Close interactions with the PIs of Project 2 (R. Kass - voltage-gated ion channels) and Project 3 (W.J. Lederer - calcium signaling) enhances each of the proposed aims as detailed below. Thus this work has the potential to determine a mechanistic basis for Sudden Cardiac Death (SCD) at the molecular level, and to develop therapeutic strategies in man based on specific molecular and mechanistic models.