VIRAL GENE TRANSFER TO MODIFY CARDIAC EXCITABILITY

描述（改编自申请人的摘要）： 这个项目是为了证明基因治疗是否是一种合理的 治疗心律失常的方法。 申请人指出，基因方面的进展 转移策略现在允许电生理学的修改， 使用编码离子通道的重组病毒载体的底物。 的 申请人建议通过创建 重组腺病毒编码：1）HERG钾通道， 是延迟整流器电流的快速激活分量的基础， IKr，以及存在于7号染色体上的这种通道的突变形式， 长QT综合征的形式;和2）KvLQT 1和minK钾通道 形成延迟整流器缓慢激活成分的亚单位 通道IKs，以及minK的突变形式，其对 IKs表达。 有待检验的中心假设是， 的野生型通道将具有抗肿瘤作用， 心脏细胞和敲除由这些通道携带电流将 延长动作电位，促进 致痫性后除极。 在分离的心肌细胞中， 申请人预测这些结构将改变净电流 平台期和复极化期，从而调节 动作电位 申请人进一步预期细胞和心脏 过表达IKr或IKs将不太可能发展为 暴露于Bay K8644后的后去极化和触发性心律失常 或哇巴因 相比之下，细胞和心脏，其中任何电流已经 在暴露于突变体后通过显性负抑制降低 预期通道/亚基具有更不稳定的节律。 主 这项工作的重点将是解决有关优化的基本问题 腺病毒介导的钾通道表达的体外和体内研究， 动作电位和电生理底物的调节。

DESCRIPTION (adapted from the applicant's abstract): The long term goal of this project is to demonstrate whether gene therapy represents a plausible approach to treat arrhythmia. The applicant notes that advances in gene transfer strategies now allow the modification of the electrophysiological substrates using recombinant viral vectors encoding ion channels. The applicant proposes to establish the feasibility of this approach by creating recombinant adenoviruses encoding: 1) the HERG potassium channel which underlies the rapidly activating component of the delayed rectifier current, IKr, and mutant forms of this channel that exist in the chromosome 7-linked form of the long QT syndrome; and 2) the KvLQT1 and minK potassium channel subunits that form the slowly activating component of the delayed rectifier channel IKs, and a mutant form of minK that has dominant negative effects on IKs expression. The central hypothesis to be tested is that over-expression of the wild-type channels will have an antiarrhythmic influence in cultured heart cells and that knock out of the current carried by these channels will lengthen the action potential and facilitate the development of arrhythmogenic afterdepolarizations. In isolated cardiac myocytes, the applicant predicts that these constructs will alter the net current during the plateau and repolarization phases and, thereby, modulate the contour of the action potential. The applicant further expects that cells and hearts overexpressing IKr or IKs will be less likely to develop afterdepolarizations and triggered arrhythmias after exposure to Bay K8644 or ouabain. In contrast, cells and heart in which either current has been reduced by dominant negative suppression upon exposure to mutant channels/subunits are expected to have more unstable rhythms. The primary focus of this work will be to address basic questions regarding optimization of adenovirus-mediated potassium channel expression in vitro and in vivo and modulation of the action potential and electrophysiologic substrate.