Human-iPSC-Derived Cardiac Stromal Cells Enhance Maturation in 3D Cardiac Microtissues and Reveal Non-cardiomyocyte Contributions to Heart Disease

Abstract

Orlova, Bellin, Mummery, and colleagues combined three hiPSC-derived cardiac cell types in 3D microtissues. Cardiomyocytes matured structurally and functionally. Replacing healthy hiPSC-cardiac fibroblasts with patient fibroblasts recapitulated aspects of arrhythmogenic cardiomyopathy. Single-cell transcriptomics, electrophysiology, metabolomics, and ultrastructural analysis revealed roles for CX43 gap junctions and cAMP signaling in the tri-cell-type dialog.Cardiomyocytes (CMs) from human induced pluripotent stem cells (hiPSCs) are functionally immature, but this is improved by incorporation into engineered tissues or forced contraction. Here, we showed that tri-cellular combinations of hiPSC-derived CMs, cardiac fibroblasts (CFs), and cardiac endothelial cells also enhance maturation in easily constructed, scaffold-free, three-dimensional microtissues (MTs). hiPSC-CMs in MTs with CFs showed improved sarcomeric structures with T-tubules, enhanced contractility, and mitochondrial respiration and were electrophysiologically more mature than MTs without CFs. Interactions mediating maturation included coupling between hiPSC-CMs and CFs through connexin 43 (CX43) gap junctions and increased intracellular cyclic AMP (cAMP). Scaled production of thousands of hiPSC-MTs was highly reproducible across lines and differentiated cell batches. MTs containing healthy-control hiPSC-CMs but hiPSC-CFs from patients with arrhythmogenic cardiomyopathy strikingly recapitulated features of the disease. Our MT model is thus a simple and versatile platform for modeling multicellular cardiac diseases that will facilitate industry and academic engagement in high-throughput molecular screening. ; European Research Council (ERCAdG 323182 STEMCARDIOVASC); European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 602423; European Union's Horizon 2020 Research and Innovation Programme under grant agreement no. 668724; Netherlands Organ-on-Chip Initiative, an NWO Gravitation project funded by the Ministry of Education, Culture and Science of the government of the Netherlands; Transnational Research Project on Cardiovascular Diseases (JTC2016_FP-40-021 ACMHF); the Netherlands Organisation for Health Research and Development ZonMW (MKMD project no. 114022504);