Real Time Screening for GIRK1/4 Channel Blockers

简介(申请人提供)：房颤(房颤)是最常见的心律失常，导致严重的发病率、死亡率和医疗费用。预计随着人口老龄化，房颤的发病率将显著增加。然而，由于其促心律失常的作用，常规抗心律失常药物在治疗房颤方面的使用受到了限制。乙酰胆碱激活的钾通道(Ik，Ach)是房颤药物治疗的一个新靶点。该通道是被称为G蛋白偶联内向整流K+(GIRK)通道的蛋白质超家族成员，由GIRK1/4亚基组成。当乙酰胆碱与心肌M_2受体结合时，Ach开放，并介导迷走神经对心率和心房兴奋的影响。最近的研究表明，在房颤中，IK、Ach是结构性活跃的，从而增强了心房的兴奋性。该项目的目标是开发一种高通量筛选(HTS)试验来鉴定抑制IK、Ach的新药。本项目要检验的假设是，膜电位敏感染料可以用作HTS传感器，用于筛选永生化心肌细胞系中的IK、Ach阻滞剂。在AIM#1测量和分析IK、Ach的方法中，将建立使用荧光成像板读取器(FLIPR)的方法。在AIM#2中，将开发一种高密度HTS分析，并使用离子通道阻滞剂文库进行筛选。在试验中发现的新化合物将在分离的房颤大鼠心脏模型中进行测试。总体而言，实验室工作的长期目标是开发治疗心律失常的新治疗策略。 公共卫生相关性：房颤(AF)是最常见的心律失常，是导致严重发病率、死亡率和医疗费用的主要原因。预计随着人口老龄化，房颤的发病率将显著增加。该项目的目标是寻找治疗房颤的新药。

DESCRIPTION (provided by applicant): Atrial fibrillation (AF) is the most commonly occurring cardiac arrhythmia and is responsible for significant morbidity, mortality and health care costs. The incidence of AF is expected to increase markedly with the aging population. However, the use of conventional anti-arrhythmic drugs for treating AF has been limited due to their pro- arrhythmic actions. One novel target for AF drug therapy is the acetylcholine-activated K+ channel (IK,Ach). This channel is a member of the super-family of proteins known as the G protein-coupled inward rectifier K+ (GIRK) channels and is composed of the GIRK1/4 subunits. IK,Ach opens upon binding of acetylcholine to the cardiac muscarinic (M2) receptor and mediates vagal effects on heat rate and atrial excitation. Recent studies indicate that IK,Ach is constitutively active in AF, thus enhancing atrial excitability. The goal of this project is to develop a high throughput-screening (HTS) assay for identifying new drugs that inhibit IK,Ach. The hypothesis to be tested in this project is that membrane potential-sensitive dyes can be used as a HTS sensor in screening for IK,Ach blockers in immortalized cardiac cell lines. In Aim #1 methods for the measurement and analysis of IK,Ach, using a fluorescent imaging plate reader (FLIPR), will be established. In Aim #2 a high density HTS assay will be developed and screened with a library of ion channel blockers. New compounds identified in the assay will be tested in an isolated rat heart model of AF. Overall, the long term goal of work in the laboratory is to develop novel therapeutic strategies for treating cardiac arrhythmias. PUBLIC HEALTH RELEVANCE: Atrial fibrillation (AF) is the most commonly occurring cardiac arrhythmia and is responsible for significant morbidity, mortality and health care costs. The incidence of AF is expected to increase markedly with the aging population. The goal of this project is to identify new drugs for treating AF.