Molecular Approaches to Arrhythmia Therapy

该计划项目的目标是开发新的抗肿瘤方法， 了解导致心脏性猝死的心律失常机制。项目4将联合收割机 生物实验和数学建模，以研究L-型钙电流之间的相互作用， (l{Ca，L}），Ca{i}瞬变和其他Ca敏感电流导致正常人中的早期后除极（埃兹）。 和衰竭的心室肌细胞（Aim 1）。该分析将用于指导治疗药物的开发。 通过改变I{Ca，L}特性抑制埃兹和EAD介导的心律失常的策略（目的2）。我们将 利用动态膜片钳方法，该方法允许虚拟电流被添加并相互作用 与活肌细胞的内源性电流双向。埃兹将被诱导与各种 干预，然后抑制钙通道阻滞剂硝苯地平。分阶段，动态夹将 加回虚拟I{Ca，L}虚拟Ca;瞬态和其他Ca敏感电流，以确定必要的 重组埃兹所需的交互。考虑到I{Ca，L}窗口电流在EAD中的关键重要性， 形成，我们将使用动态钳方法来探索动力学和/或电压依赖性 可以改变I{Ca，L}的性质以抑制分离的肌细胞中的“重建的”埃兹。正常I{Ca，L}在 动态箝位将被适当修改的虚拟I{Ca，L}代替，以识别哪些修改 消除埃兹同时保持正常的Ca{i}瞬变（目标2a）。利用这些信息，我们将探索 兔心室肌细胞I{Ca，L}的遗传修饰，以鉴定抑制埃兹的干预措施 在不对E-C偶联产生不利影响的情况下，使用两种策略：i）辅助Ca Ca通道亚基取代相应的天然Ca通道亚基。ii）天然Ca的下调 通道亚单位在成年兔心室肌细胞中使用适当的病毒载体。这些混合 模型/实验研究有望促进我们对EAD机制的理解 形成并确定新的抗肿瘤策略。项目4将补充建模 项目1中的研究、P2中的细胞水平研究和项目3中的组织水平研究。

The goal of this Program Project is to develop novel antiarrhythmic approaches based on improved understanding of the arrhythmia mechanisms causing sudden cardiac death. Project 4 will combine biological experiments and mathematical modeling to study how the interaction between the L-type Ca curret (l{Ca,L}), the Ca{i} transient and other Ca-sensitive currents lead to early afterdepolarizations (EADs) in normal and failing ventricular myocytes (Aim 1). This analysis will then be used to guide development of therapeutic strategies to suppress EADs and EAD-mediated arrhythmias by modifying I{Ca,L} properties (Aim 2). We will utilize the dynamic patch clamp approach which permits virtual currents to be added and interact bidirectionally with the endogenous currents of a live myocyte. EADs will be induced with various interventions, and then suppressed by the Ca channel blocker nifedepine. In stages, the dynamic clamp will add back a virtual I{Ca,L} virtual Ca; transient, and other Ca-sensitive currents to determine the necessary interactions required to reconstitute EADs. Given the critical importance of the I{Ca,L} window current in EAD formation, we will use the dynamic clamp approach to explore how the kinetic and/or voltage dependent properties of I{Ca,L} can be modified to suppress "reconstituted" EADs in isolated myocytes. The normal I{Ca,L} in the dynamic clamp will be replaced with an appropriately modified virtual I{Ca,L} to identify which modifications eliminate EADs while preserving a normal Ca{i} transient (Aim 2a). Using this information, we will explore genetic modifications of I{Ca,L} in rabbit ventricular myocytes to identify interventions which suppress EADs without adversely affecting E-C coupling, using two strategies: i) genetic overexpression of ancillary Ca channel subunits to replace the corresponding native Ca channel subunits. ii) downregulation of native Ca channel subunits in the adult rabbit ventricular myocytes using appropriate viral vectors. These hybrid modeling/experimental studies promise to both advance our understanding of the mechanisms of EAD formation and identify novel antiarrhythmic strategies. Project 4 will be complemented by the modeling studies in Project 1, cellular level studies in P2, and tissue level studies in Project 3.