Measuring the systolic and the diastolic properties of single human pluripotent stem-cell cardiomyocyte for drug testing and disease modeling

Abstract

Abstract Background The advent of human pluripotent stem cell–derived cardiomyocytes (hPSC-CMs) provided exciting tools for cardiovascular physiological studies, disease modeling and drug testing applications. Current platforms for studying the mechanical properties of human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) as single-cells do not measure forces directly, require numerous assumptions, and cannot study cell mechanics at different loading conditions. Objective To establish a novel platform to assess the active and passive mechanical properties of single-cell hPSC-CMs at different loading conditions and to demonstrate the potential of this approach for drug testing and disease modeling applications. Methods and results To allow morphological maturation, hPSC-CMs were treated with Tri-iodo-thyronine hormone, dexamethasone and Insulin-like growth factor-1. The hPSC-CM were then lifted and attached to a highly sensitive optical-force transducer and a piezoelectric length controller and electrically-stimulated. The attached hPSC-CM remained intact and contractile allowing evaluation of their passive and active mechanical properties. Utilizing this technique, single-cell hPSC-CMs exhibited positive length-tension (Frank-Starling) relationships, and appropriate inotropic, klinotropic, and lusitropic changes in response to treatment with isoproterenol. The unique potential of the approach for drug testing and disease modeling was exemplified by treating the cells with doxorubicin (a potential cardiotoxic anti-cancer agent) and omecamtiv mecarbil (a positive ionotropic drug currently in stage 3 clinical trial). The results of these studies recapitulated the drugs' known actions to suppress (doxorubicin) and augment (omecamtiv mecarbil at low dose) cardiomyocyte contractility. Finally, novel insights were gained regarding the cellular effects of these drugs as doxorubicin treatment led to cellular mechanical alternans and high doses of omecamtiv mecarbil suppressed contractility and worsened the cellular diastolic properties. Conclusion A novel method that allows direct active and passive force measurements from single hPSC-CMs at different loading conditions for the first time was established and validated. Our results highlight the potential implications of this novel approach for pharmacological studies and disease modeling studies. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): European Research Council