Institute of Physiology I, Life and Brain Center, Medical Faculty, University of Bonn, Sigmund-Freud-Str. 25, 53127, Bonn, Germany.
Research Training Group 1873, University of Bonn, 53127, Bonn, Germany.
Sci Rep. 2017 Aug 29;7(1):9629. doi: 10.1038/s41598-017-09760-7.
Side effects on cardiac ion channels are one major reason for new drugs to fail during preclinical evaluation. Herein we propose a simple optogenetic screening tool measuring extracellular field potentials (FP) from paced cardiomyocytes to identify drug effects over the whole physiological heart range, which is essential given the rate-dependency of ion channel function and drug action. Human induced pluripotent stem cell-derived cardiomyocytes were transduced with an adeno-associated virus to express Channelrhodopsin2 and plated on micro-electrode arrays. Global pulsed illumination (470 nm, 1 ms, 0.9 mW/mm) was applied at frequencies from 1 to 2.5 Hz, which evoked FP simultaneously in all cardiomyocytes. This synchronized activation allowed averaging of FP from all electrodes resulting in one robust FP signal for analysis. Field potential duration (FPD) was ~25% shorter at 2.5 Hz compared to 1 Hz. Inhibition of hERG channels prolonged FPD only at low heart rates whereas Ca channel block shortened FPD at all heart rates. Optogenetic pacing also allowed analysis of the maximum downstroke velocity of the FP to detect drug effects on Na channel availability. In principle, the presented method is well scalable for high content cardiac toxicity screening or personalized medicine for inherited cardiac channelopathies.
心脏离子通道的副作用是新药在临床前评估中失败的一个主要原因。在此，我们提出了一种简单的光遗传学筛选工具，可测量起搏心肌细胞的细胞外场电位 (FP)，以识别整个生理心脏范围内的药物作用，鉴于离子通道功能和药物作用的速率依赖性，这是必不可少的。用人诱导多能干细胞衍生的心肌细胞转导腺相关病毒表达 Channelrhodopsin2，并铺在微电极阵列上。以 1 至 2.5 Hz 的频率施加全局脉冲光照 (470nm，1ms，0.9mW/mm)，同时激发所有心肌细胞的 FP。这种同步激活允许对所有电极的 FP 进行平均，从而得到一个用于分析的稳健 FP 信号。与 1 Hz 相比，2.5 Hz 时 FP 持续时间 (~25%)缩短。抑制 hERG 通道仅在低心率时延长 FPD，而钙通道阻断则在所有心率下缩短 FPD。光遗传学起搏还允许分析 FP 的最大下冲速度，以检测钠通道可用性对药物的影响。原则上，所提出的方法非常适合高通量心脏毒性筛选或遗传性心脏通道病的个性化医疗。
