Abnormal Calcium Handling Properties Underlie Familial Hypertrophic Cardiomyopathy Pathology in Patient-Specific Induced Pluripotent Stem Cells

Familial hypertrophic cardiomyopathy (HCM) is a prevalent hereditary cardiac disorder linked to arrhythmia and sudden cardiac death. While the causes of HCM have been identified as genetic mutations in the cardiac sarcomere, the pathways by which sarcomeric mutations engender myocyte hypertrophy and electrophysiological abnormalities are not understood. To elucidate the mechanisms underlying HCM development, we generated patient-specific induced pluripotent stem cell cardiomyocytes (iPSC-CMs) from a ten-member family cohort carrying a hereditary HCM missense mutation (Arg663His) in the MYH7 gene. Diseased iPSC-CMs recapitulated numerous aspects of the HCM phenotype including cellular enlargement and contractile arrhythmia at the single-cell level. Calcium (Ca2+) imaging indicated dysregulation of Ca2+ cycling and elevation in intracellular Ca2+ ([Ca2+]i) are central mechanisms for disease pathogenesis. Pharmacological restoration of Ca2+ homeostasis prevented development of hypertrophy and electrophysiological irregularities. We anticipate that these findings will help elucidate the mechanisms underlying HCM development and identify novel therapies for the disease. ► Patient-specific iPSC-CMs recapitulate the HCM phenotype at the single-cell level ► iPSC-CMs with the HCM Arg663His mutation have irregular Ca2+ handling properties ► Elevation in [Ca2+]i induces both hypertrophy and arrhythmia in iPSC-CMs ► Pharmacological treatment of Ca2+ imbalance prevents HCM phenotype development Modeling of familial hypertrophic cardiomyopathy using human iPSCs highlights a role for Ca2+ dysregulation in disease pathology.