title: Rbm20-deficient cardiogenesis reveals early disruption of RNA processing and sarcomere remodeling establishing a developmental etiology for dilated cardiomyopathy.
abstract: Dilated cardiomyopathy (DCM) due to mutations in RBM20, a gene encoding an RNA-binding protein, is associated with high familial penetrance, risk of progressive heart failure and sudden death. Although genetic investigations and physiological models have established the linkage of RBM20 with early-onset DCM, the underlying basis of cellular and molecular dysfunction is undetermined. Modeling human genetics using a high-throughput pluripotent stem cell platform was herein designed to pinpoint the initial transcriptome dysfunction and mechanistic corruption in disease pathogenesis. Tnnt2-pGreenZeo pluripotent stem cells were engineered to knockdown Rbm20 (shRbm20) to determine the cardiac-pathogenic phenotype during cardiac differentiation. Intracellular Ca(2+) transients revealed Rbm20-dependent alteration in Ca(2+) handling, coinciding with known pathological splice variants of Titin and Camk2d genes by Day 24 of cardiogenesis. Ultrastructural analysis demonstrated elongated and thinner sarcomeres in the absence of Rbm20 that is consistent with human cardiac biopsy samples. Furthermore, Rbm20-depleted transcriptional profiling at Day 12 identified Rbm20-dependent dysregulation with 76% of differentially expressed genes linked to known cardiac pathology ranging from primordial Nkx2.5 to mature cardiac Tnnt2 as the initial molecular aberrations. Notably, downstream consequences of Rbm20-depletion at Day 24 of differentiation demonstrated significant dysregulation of extracellular matrix components such as the anomalous overexpression of the Vtn gene. By using the pluripotent stem cell platform to model human cardiac disease according to a stage-specific cardiogenic roadmap, we established a new paradigm of familial DCM pathogenesis as a developmental disorder that is patterned during early cardiogenesis and propagated with cellular mechanisms of pathological cardiac remodeling.
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Rosanna
authors.initials: R
authors.lastname: Beraldi
authors.affiliation: Division of Biomedical Statistics and Informatics, Department of Health Sciences Research.
authors.forename: Xing
authors.initials: X
authors.lastname: Li
authors.affiliation: Division of Cardiovascular Diseases, Center of Regenerative Medicine.
authors.forename: Almudena
authors.initials: A
authors.lastname: Martinez Fernandez
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Santiago
authors.initials: S
authors.lastname: Reyes
authors.affiliation: Division of Cardiovascular Diseases.
authors.forename: Frank
authors.initials: F
authors.lastname: Secreto
authors.affiliation: Division of Cardiovascular Diseases, Center of Regenerative Medicine, Division of Pediatric Cardiology, Molecular Pharmacology and Experimental Therapeutics.
authors.forename: Andre
authors.initials: A
authors.lastname: Terzic
authors.affiliation: Division of Cardiovascular Diseases, Division of Pediatric Cardiology, Molecular Pharmacology and Experimental Therapeutics.
authors.forename: Timothy M
authors.initials: TM
authors.lastname: Olson
authors.affiliation: Center of Regenerative Medicine, Molecular Pharmacology and Experimental Therapeutics, General Internal Medicine and Transplant Center, Mayo Clinic, Rochester, MN 55905, USA nelson.timothy@mayo.edu.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Nelson
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002311:Cardiomyopathy, Dilated / Q000209:etiology* / Q000473:pathology; D002454:Cell Differentiation; D002460:Cell Line; D058732:Embryoid Bodies / Q000378:metabolism; D020869:Gene Expression Profiling; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D006321:Heart / Q000254:growth & development*; D006801:Humans; D051379:Mice; D008954:Models, Biological; D039904:Pluripotent Stem Cells / Q000378:metabolism; D012326:RNA Splicing; D016601:RNA-Binding Proteins / Q000378:metabolism*; D012518:Sarcomeres / Q000473:pathology* / Q000648:ultrastructure
chemical_list: C584322:RBM20 protein, mouse; D016601:RNA-Binding Proteins; C543725:ribonucleic acid binding motif protein 20, human; D002118:Calcium