Enhanced Electrophysiological Maturation Of Human Pluripotent Stem Cell Derived Cardiomyocytes By An Optimal Combination Of Metabolic Modulators

Human pluripotent stem cell derived cardiomyocytes (hPSC-CMs) have emerged as ideal cell source for heart regeneration. Transplantation of hPSC-CMs to the damaged heart restores contractile function via electromechanical coupling between host and graft CMs. However, a few hurdles still remain in safety for clinical application, especially a transient period of ventricular arrhythmias after transplantation into large animals. Automaticity of graft cells, related to the electrical immaturity of hPSC-CMs, most likely triggers arrhythmic events. Here, we hypothesized that modulating metabolism toward an adult-like state would control ion channel gene expression and enhance electrophysiological maturation of hPSC-CMs in vitro. We systematically optimized combination of major metabolic components, including metabolic hormones, energy source and energy sensing, to achieve ion channel gene expression and electrophysiological phenotypes that more closely resemble adult cardiomyocytes. hPSC-CMs treated with optimized media displayed slower beat rates, longer field potentials, faster conduction velocities, and improved Ca 2+ kinetics. Moreover, optimized media increased mitochondrial content, respiratory capacity and fatty acid utilization for larger energy production, induced cell cycle exit, improved global transcriptome and sarcomere structure, and increased cell size. Subsequently, the matured cells were transplanted to mouse hearts, showing the engraftment comparable to immature hPSC-CMs. These results indicate that metabolic reprogramming can enhance many elements of maturation, including electrophysiology, myofibril organization, cell cycle, and capacity for oxidative phosphorylation.