Cardiac Non-myocyte Cells Show Enhanced Pharmacological Function Suggestive of Contractile Maturity in Stem Cell Derived Cardiomyocyte Microtissues

• Published in: Toxicological sciences Vol. 152; no. 1; pp. 99 - 112
• Main Authors: Ravenscroft, Stephanie M, Pointon, Amy, Williams, Awel W, Cross, Michael J, Sidaway, James E
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01.07.2016
• Subjects: Calcium Signaling - drug effects; Cardiac Pacing, Artificial; Cardiotonic Agents - pharmacology; Cell Communication; Cells, Cultured; Coculture Techniques; Dose-Response Relationship, Drug; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Fibroblasts - drug effects; Fibroblasts - metabolism; Function of Non-Myocyte Cells Derived from Stem Cell Cardiomyocyte Model; Human Embryonic Stem Cells - drug effects; Human Embryonic Stem Cells - metabolism; Humans; Induced Pluripotent Stem Cells - drug effects; Induced Pluripotent Stem Cells - metabolism; Myocardial Contraction - drug effects; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - metabolism; Phenotype; S100 Proteins - metabolism; Spheroids, Cellular; Time Factors; hESC-CMs; cardiotoxicity; inotropy; S100A1; cardiac microtissue; contractility
• ISSN: 1096-6080; 1096-0929
• DOI: 10.1093/toxsci/kfw069

The immature phenotype of stem cell derived cardiomyocytes is a significant barrier to their use in translational medicine and pre-clinical in vitro drug toxicity and pharmacological analysis. Here we have assessed the contribution of non-myocyte cells on the contractile function of co-cultured human embryonic stem cell derived cardiomyocytes (hESC-CMs) in spheroid microtissue format. Microtissues were formed using a scaffold free 96-well cell suspension method from hESC-CM cultured alone (CM microtissues) or in combination with human primary cardiac microvascular endothelial cells and cardiac fibroblasts (CMEF microtissues). Contractility was characterized with fluorescence and video-based edge detection. CMEF microtissues displayed greater Ca(2+ )transient amplitudes, enhanced spontaneous contraction rate and remarkably enhanced contractile function in response to both positive and negative inotropic drugs, suggesting a more mature contractile phenotype than CM microtissues. In addition, for several drugs the enhanced contractile response was not apparent when endothelial cell or fibroblasts from a non-cardiac tissue were used as the ancillary cells. Further evidence of maturity for CMEF microtissues was shown with increased expression of genes that encode proteins critical in cardiac Ca(2+ )handling (S100A1), sarcomere assembly (telethonin/TCAP) and β-adrenergic receptor signalling. Our data shows that compared with single cell-type cardiomyocyte in vitro models, CMEF microtissues are superior at predicting the inotropic effects of drugs, demonstrating the critical contribution of cardiac non-myocyte cells in mediating functional cardiotoxicity.