Abstract 13764: Development of in vitro Drug-Induced Cardiotoxicity Assay by Using Three-Dimensional Cardiac Tissues Derived From Human Induced Pluripotent Stem Cells

Abstract

Introduction: In vitro drug-induced cardiotoxicity assay is a critical step in drug discovery for clinical use. Use of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) is promising for this purpose; however, dissociated single iPSC-CMs are concerned by their functionality, while generation of artificial cardiac tissue by iPSC-CMs mimicking native cardiac tissue has not been established for the cardiotoxicity assay. We hypothesized that three-dimensional (3D) cardiac tissues derived from human iPSC-CMs (3D-hiPSC-CMs) may be used for in vitro drug-induced cardiotoxicity assay. Methods and Results: Single hiPSC-CMs coated with fibronectin and gelatin nanofilms were cultured in a cell culture insert to generate 3D-hiPSC-CMs. Histologically, the 3D-hiPSC-CMs formed thick multilayers dependent upon the number of seeded cells. In addition, the 3D-hiPSC-CMs exhibited sarcomere structure in the myocytes and extracellular matrix proteins, such as fibronectin, laminins or collagen type I/III. Electrophysiologically, synchronous extracellular electrical potentials were recorded in the entire 3D-hiPSC-CMs. Addition of cytotoxic doxorubicin at 2 uM induced release of lactate dehydrogenase (LDH), while that at 1 uM induced reduction of cell viability as assessed by WST assay. In contrast, addition of E-4031, hERG type potassium channel blocker, failed to induce cytotoxicity in the 3D-hiPSC-CMs by LDH and WST assay. Instead, E-4031 at 30 nM induced significant decrease in peak Ca2+ transient (80±4 vs 61±10 /min), beating rate (81±4 vs 77±7 /min), contraction velocity (9.2±1.9 vs 6.7±1.9 um/sec) and relaxation velocity (7.8±1.5 vs 3.3±0.8 um/sec). On the other hand, addition of Isoproterenol at 100 nM induced significant increase in peak Ca2+ transient (80±4.1 vs 96±8.0 /min), and beating rate (81±4.0 vs 115±11 /min), but failed to induce significant increase in contraction velocity (9.2±1.9 vs 11.4±1.4 um/sec) or relaxation velocity (7.8±1.5 vs 11±0.6 um/sec). Conclusions: The 3D-hiPSC-CMs exhibited doxorubicin-sensitive cytotoxicity and hERG channel blocker/isoproterenol-sensitive electrical activity in vitro, indicating its usefulness for drug-induced cardiotoxicity assay or drug screening system for drug discovery.