title: Modeling structural and functional deficiencies of RBM20 familial dilated cardiomyopathy using human induced pluripotent stem cells.
abstract: Dilated cardiomyopathy (DCM) is a leading cause of heart failure. In families with autosomal-dominant DCM, heterozygous missense mutations were identified in RNA-binding motif protein 20 (RBM20), a spliceosome protein induced during early cardiogenesis. Dermal fibroblasts from two unrelated patients harboring an RBM20 R636S missense mutation were reprogrammed to human induced pluripotent stem cells (hiPSCs) and differentiated to beating cardiomyocytes (CMs). Stage-specific transcriptome profiling identified differentially expressed genes ranging from angiogenesis regulator to embryonic heart transcription factor as initial molecular aberrations. Furthermore, gene expression analysis for RBM20-dependent splice variants affected sarcomeric (TTN and LDB3) and calcium (Ca(2+)) handling (CAMK2D and CACNA1C) genes. Indeed, RBM20 hiPSC-CMs exhibited increased sarcomeric length (RBM20: 1.747 ± 0.238 µm versus control: 1.404 ± 0.194 µm; P < 0.0001) and decreased sarcomeric width (RBM20: 0.791 ± 0.609 µm versus control: 0.943 ± 0.166 µm; P < 0.0001). Additionally, CMs showed defective Ca(2+) handling machinery with prolonged Ca(2+) levels in the cytoplasm as measured by greater area under the curve (RBM20: 814.718 ± 94.343 AU versus control: 206.941 ± 22.417 AU; P < 0.05) and higher Ca(2+) spike amplitude (RBM20: 35.281 ± 4.060 AU versus control:18.484 ± 1.518 AU; P < 0.05). β-adrenergic stress induced with 10 µm norepinephrine demonstrated increased susceptibility to sarcomeric disorganization (RBM20: 86 ± 10.5% versus control: 40 ± 7%; P < 0.001). This study features the first hiPSC model of RBM20 familial DCM. By monitoring human cardiac disease according to stage-specific cardiogenesis, this study demonstrates RBM20 familial DCM is a developmental disorder initiated by molecular defects that pattern maladaptive cellular mechanisms of pathological cardiac remodeling. Indeed, hiPSC-CMs recapitulate RBM20 familial DCM phenotype in a dish and establish a tool to dissect disease-relevant defects in RBM20 splicing as a global regulator of heart function.
authors.affiliation: Center for Clinical and Translational Sciences, Center for Regenerative Medicine.
authors.forename: Saranya P
authors.initials: SP
authors.lastname: Wyles
authors.affiliation: Department of Health Sciences Research, Division of Biomedical Statistics and Informatics.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Sybil C
authors.initials: SC
authors.lastname: Hrstka
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Santiago
authors.initials: S
authors.lastname: Reyes
authors.affiliation: Division of General Internal Medicine, Department of Molecular Pharmacology and Experimental Therapeutics.
authors.forename: Saji
authors.initials: S
authors.lastname: Oommen
authors.affiliation: Children's Hospital Research Center, Sanford Research, Sioux Falls, SD 57104, USA.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Beraldi
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Jessica
authors.initials: J
authors.lastname: Edwards
authors.affiliation: Center for Regenerative Medicine, Division of Cardiovascular Diseases, Department of Molecular Pharmacology and Experimental Therapeutics, Department of Medical Genetics.
authors.forename: Andre
authors.initials: A
authors.lastname: Terzic
authors.affiliation: Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Cardiovascular Genetics Research Laboratory and.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Olson
authors.affiliation: Center for Regenerative Medicine, Division of General Internal Medicine, Department of Molecular Pharmacology and Experimental Therapeutics, Division of Pediatric Cardiology, Transplant Center, Mayo Clinic, Rochester, MN 55905, USA and nelson.timothy@mayo.edu.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Nelson
mesh_terms: D000328:Adult; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002311:Cardiomyopathy, Dilated / Q000235:genetics* / Q000378:metabolism / Q000503:physiopathology; D002454:Cell Differentiation; D005260:Female; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism* / Q000502:physiology; D008297:Male; D051379:Mice; D008954:Models, Biological; D020125:Mutation, Missense; D032383:Myocytes, Cardiac / Q000378:metabolism*; D010375:Pedigree; D012326:RNA Splicing / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics*; D059467:Transcriptome; D055815:Young Adult
chemical_list: D016601:RNA-Binding Proteins; C543725:ribonucleic acid binding motif protein 20, human; D002118:Calcium