Isogenic Pairs of hiPSC-CMs with Hypertrophic Cardiomyopathy/LVNC-Associated ACTC1 E99K Mutation Unveil Differential Functional Deficits

• DOI: 10.1016/j.stemcr.2018.10.006
• Publication Date: 2018-11-01T14:43:51Z
• Authors: James G.W. Smith; Thomas Owen; Jamie R. Bhagwan; Diogo Mosqueira; Elizabeth Scott; Ingra Mannhardt; Asha Patel; Roberto Barriales...; Lorenzo Monserrat; Arne Hansen; Thomas Eschenhagen; Sian E. Harding; Steve Marston; Chris Denning
• Keywords: MECHANISM; Heart Defects, Congenital; Medicine (General); QH301-705.5; Induced Pluripotent Stem Cells; 610; CHILDREN; MOUSE; arrhythmia; CARDIOMYOCYTES; Article; 03 medical and health sciences; R5-920; Cell & Tissue Engineering; contractile function; Humans; Myocytes, Cardiac; ABERRANT CA2+ RELEASE; Calcium Signaling; Biology (General); ENGINEERED HEART-TISSUE; GENE-EXPRESSION; Gene Editing; 0303 health sciences; Science & Technology; Tissue Engineering; Arrhythmias, Cardiac; Cell Biology; Cardiomyopathy, Hypertrophic; DILATED CARDIOMYOPATHY; Myocardial Contraction; Actins; 3. Good health; ALPHA-CARDIAC ACTIN; Mutation; Calcium; CRISPR-Cas Systems; hypertrophy; Life Sciences & Biomedicine; PLURIPOTENT STEM-CELLS; cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is a primary disorder of contractility in heart muscle. To gain mechanistic insight and guide pharmacological rescue, this study models HCM using isogenic pairs of human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) carrying the E99K-ACTC1 cardiac actin mutation. In both 3D engineered heart tissues and 2D monolayers, arrhythmogenesis was evident in all E99K-ACTC1 hiPSC-CMs. Aberrant phenotypes were most common in hiPSC-CMs produced from the heterozygote father. Unexpectedly, pathological phenotypes were less evident in E99K-expressing hiPSC-CMs from the two sons. Mechanistic insight from Ca2+ handling expression studies prompted pharmacological rescue experiments, wherein dual dantroline/ranolazine treatment was most effective. Our data are consistent with E99K mutant protein being a central cause of HCM but the three-way interaction between the primary genetic lesion, background (epi)genetics, and donor patient age may influence the pathogenic phenotype. This illustrates the value of isogenic hiPSC-CMs in genotype-phenotype correlations.