Chronic assessment of hERG trafficking on repolarisation and cytotoxicity in iPSC cardiomyocytes

• Published in: Journal of pharmacological and toxicological methods Vol. 133; p. 107635
• Main Authors: Smith, Godfrey, Watters, Taylor, Ghasemi, Shahrum, Henderson, Lewis, Bryant, Mark, MacQuaide, Niall
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01.05.2025
• ISSN: 1056-8719
• DOI: 10.1016/j.vascn.2025.107635

iPSC-derived cardiomyocytes (iPSC-CMs) have an established role determining the effects of drugs after acute (<1 h) exposure. A host of toxic actions have been shown to develop during chronic (>12 h) drug exposure, including hERG trafficking issues; in vivo tests used to detect these are expensive, involve complex interpretation and may include species dependent differences. To assess the performance of an extended iPSC-CM assay to investigate longer term toxic hERG trafficking actions using serum-free solutions. Functional cellular assays were monitored over a prolonged (72 h) exposure time at 24 h intervals: (i) Electrophysiology using optical voltage measurements (ii) contractile kinetics and amplitude using a camera-based algorithm (iii) iPSC-CM monolayer integrity based on assessment of wide field images and (iv) extracellular lactate dehydrogenase (LDH) measurements that assess plasmalemma integrity. iCell2 (FujiFilm-CDI) iPSC-CMs were seeded on a 96well plate and incubated in a serum free media (FluoroBrite, ThermoFisher). Automated image and signal analysis was completed using Clyde Biosciences a proprietary analysis platform (CellOPTIQ®). 6 concentrations of compounds known to alter hERG trafficking were studied and chronic toxicity, electrophysiological, metabolic dysfunction were assessed. All drugs showed effects across the parameters studied with clear prolongation of APD90 after 24 h and prolonging further at 48 h. Functional data from the DMSO control wells were stable over 72 h, but small, significant loss of cell integrity and raised LDH signals were detected after 72 h. iPSC-CMs can be used to assess medium-long term actions of hERG trafficking drugs allowing mechanistic interpretation. This represents a highly specific system for chronic assessment of human cardiovascular toxicity risk such as hERG trafficking.