Frequency-dependent drug screening using optogenetic stimulation of human iPSC-derived cardiomyocytes.

ABSTRACT: 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/mm²) 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 Ca²⁺ 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.

SUBMITTER: Lapp H 

PROVIDER: S-EPMC5575076 | biostudies-literature | 2017 Aug

REPOSITORIES: biostudies-literature