D.J. Owens, J. Haning, L. Erickson-Herbrandson, and J. Aho
Cardiotoxicity is a leading cause for the recall of commercial pharmaceutical drugs and the failure of compounds during drug development. Traditional models for studying cardiotoxicity in vitro use non-cardiac cells, such as CHO or HEK cells, transduced with cardiac-muscle related ion channels. These models lack the complexity of in vivo cardiomyocytes, thus limiting their predictive power during drug screening. Use of animal models for drug screening is confounded by species differences in ion channels involved in the cardiac action potential. Pluripotent stem cell-derived functional cardiomyocytes provide a simple and renewable alternative model for in vitro drug toxicity studies as well as for cardiac disease modeling and the development of clinical therapies. We have previously shown that the StemXVivo™ Cardiomyocyte Differentiaton Kit (Catalog # SC032) efficiently differentiates human pluripotent stem cells into functional cardiomyocytes. In this study, we show the utility of the cardiomyocytes produced using the StemXVivo™ Cardiomyocyte Differentiation Kit, including the long-term viability of cardiomyocytes in culture, the successful re-plating of kit-derived cardiomyocytes, and the efficient transfection of cardiomyocytes with fluorescently-tagged wild-type and mutant calcium signaling proteins. We also demonstrate that kit-derived cardiomyocytes respond to known cardio-modulatory small molecules; the alpha 1-adrenoreceptor agonist (Phenylephedrine) increased the rate of cardiomyocyte contraction, while Ca2+ channel blockers (Verapamil, Dilatiazem) decreased cardiomyocyte contraction rate. Last, we show that multi-analyte Luminex® technology is an efficient tool for high throughput drug efficacy and toxicity testing. Increases in Pro-BNP secretion and Troponin T release were detected in StemXVivo™ Cardiomyocyte Differentiation Kit-derived cardiomyocyte cultures in response to Endothelin-1 and Doxorubicin treatment, respectively.