Integral approach to organelle profiling in human iPSC-derived cardiomyocytes enhances in-vitro cardiac-safety classification

Efficient preclinical prediction of cardiovascular side effects poses a pivotal challenge for the pharmaceutical industry. Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are becoming increasingly important in this field due to inaccessibility of human native cardiac tissue. Functional changes in hiPSC-CMs such as electrophysiological abnormalities, are commonly studied and considered clinically predictive. However, other clinically-relevant safety parameters, such as structural toxicity, are less understood. This study utilized hiPSC-CMs from multiple donors, cultured in serum-free conditions and treated with a library of 17 small molecules with stratified cardiac side effects, to establish an in-vitro drug screening protocol that leverages the power of morphological profiling with established functional readouts. High-content imaging of subcellular organelles, combined with multi-electrode array (MEA) data, was analyzed to identify cardiac safety clusters. Both supervised and unsupervised clustering revealed patterns associated with known clinical side effects. Overall, clustering based on morphological data more accurately reflected clinical classifications than electrophysiology alone. RNA-sequencing was used to support the mechanistic insights derived from morphological profiling, validating the former as a valuable cardiotoxicity tool. Results demonstrate that a combined approach of analyzing morphology, and electrophysiology enhances in-vitro prediction and understanding of drug cardiotoxicity.