A Molecular Study of Cardiac Repolarization

描述(由申请人提供)： 自从对心电图的最早描述以来，科学家们一直着迷于每次去极化之间的静止期。心脏周期的这一阶段现在被认为是一系列高度协调的事件，可以恢复静息的膜电位。复极化是一种复杂的现象，取决于单个通道、受体、细胞骨架和膜的功能，所有这些都在多细胞结构中。在过去的十年中，复极的扰动被直接牵连到致命性心律失常中。鉴于这种对复极化像差的敏感性，有强大的机制来捍卫这一过程也就不足为奇了。该领域的核心假设之一是，心脏具有复极储备，允许它容忍微小的复极扰动，但这种储备可能会被严重或累积的侮辱所淹没。考虑到这一过程的复杂性，为了更好地理解复极化，需要一个能够快速进行基因操作和分析的完整的动物模型生物体。我们的初步数据表明，复极障碍在斑马鱼中表现为心动过缓，这一生物将为分析心脏复极提供一个很好的模型。这一建议从三个具体目的系统地研究斑马鱼的心脏复极：1)建立斑马鱼对LKR阻断药物反应的心动过缓机制；2)表征人类长QT综合征基因的斑马鱼同源基因，并评估它们在斑马鱼心脏复极中的作用；3)通过调节斑马鱼复极的分子决定因素，系统地测试复极储备的概念。应聘者有化学和分子生物学背景，最近完成了心脏病学和电生理学奖学金培训。米兰博士于2003年7月被任命为MGH心脏病科的工作人员，该科为他的工作投入了大量资源。他已经召集了一个由三名赞助商组成的小组，他们将在斑马鱼生物学、遗传学和心血管细胞生理学方面指导他。米兰博士的顾问小组包括心脏复极、心肌细胞信号转导和药物引起的心律失常领域的领军人物。米兰博士将通过一个全面的教育计划来补充本提案中描述的实验工作，包括实验室会议、期刊俱乐部、研讨会、科学会议和正式课程。这一计划是精心设计的，旨在促进米兰博士在科学、专业和个人方面的进步发展，最终成为基础心脏电生理学领域的一名独立研究员。

DESCRIPTION (provided by applicant): Since the earliest descriptions of the electrocardiogram, the period of quiescence between each depolarization, has fascinated scientists. This phase of the cardiac cycle is now known to be a highly orchestrated series of events that restore the resting membrane potential. Repolarization is a complex phenomenon, dependent on the functions of individual channels, receptors, cytoskeleton and the membrane, all within a multicellular structure. In the last decade, perturbations of repolarization have been directly implicated in fatal cardiac arrhythmias. Given this sensitivity to aberrations of repolarization, it is not surprising that there are robust mechanisms defending this process. One of the central hypotheses in the field is that the heart has a repolarization reserve that allows it to tolerate small perturbatations of repolarization, but which can be overwhelmed by severe or cumulative insults. Given the complexity of this process, an integrated whole animal model organism amenable to rapid genetic manipulation and analysis will be required for a better understanding of repolarization. Our preliminary data suggest that disturbances of repolarization are manifest as bradycardia in the zebrafish, and that this organism will provide a good model for the analysis of cardiac repolarization. This proposal takes a systematic approach to the study of cardiac repolarization in the zebrafish in three specific aims: 1) establish the mechanism of bradycardia in response to lKr blocking drugs in the zebrafish; 2) characterize the zebrafish orthologs of the human long QT syndrome genes and assess their role in zebrafish cardiac repolarization; 3) systematically test the concept of repolarization reserve by modulating the molecular determinants of repolarization in the zebrafish. The candidate has a background in chemistry and molecular biology and has recently completed cardiology and electrophysiology fellowship training. Dr. Milan was appointed to the staff of the Cardiology Division at MGH in July 2003, and the Division has committed numerous resources to his work. He has assembled a group of three sponsors who will guide him in both zebrafish biology and genetics and cardiovascular cellular physiology. Dr. Milan's panel of advisors includes leaders in the fields of cardiac repolarization, cardiomyocyte signal transduction and drug-induced cardiac arrhythmias. Dr. Milan will complement the experimental work described in this proposal with a comprehensive educational program including lab meetings, journal clubs, seminars, scientific meetings, and formal coursework. This plan is carefully designed to result in Dr. Milan's progressive scientific, professional and personal development, culminating in his emergence as an independent investigator in the field of basic cardiac electrophysiology.