title: Functional abnormalities in iPSC-derived cardiomyocytes generated from CPVT1 and CPVT2 patients carrying ryanodine or calsequestrin mutations.
abstract: Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia characterized by syncope and sudden death occurring during exercise or acute emotion. CPVT is caused by abnormal intracellular Ca(2+) handling resulting from mutations in the RyR2 or CASQ2 genes. Because CASQ2 and RyR2 are involved in different aspects of the excitation-contraction coupling process, we hypothesized that these mutations are associated with different functional and intracellular Ca(²+) abnormalities. To test the hypothesis we generated induced Pluripotent Stem Cell-derived cardiomyocytes (iPSC-CM) from CPVT1 and CPVT2 patients carrying the RyR2(R420Q) and CASQ2(D307H) mutations, respectively, and investigated in CPVT1 and CPVT2 iPSC-CM (compared to control): (i) The ultrastructural features; (ii) the effects of isoproterenol, caffeine and ryanodine on the [Ca(2+) ]i transient characteristics. Our major findings were: (i) Ultrastructurally, CASQ2 and RyR2 mutated cardiomyocytes were less developed than control cardiomyocytes. (ii) While in control iPSC-CM isoproterenol caused positive inotropic and lusitropic effects, in the mutated cardiomyocytes isoproterenol was either ineffective, caused arrhythmias, or markedly increased diastolic [Ca(2+) ]i . Importantly, positive inotropic and lusitropic effects were not induced in mutated cardiomyocytes. (iii) The effects of caffeine and ryanodine in mutated cardiomyocytes differed from control cardiomyocytes. Our results show that iPSC-CM are useful for investigating the similarities/differences in the pathophysiological consequences of RyR2 versus CASQ2 mutations underlying CPVT1 and CPVT2 syndromes.
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Atara
authors.initials: A
authors.lastname: Novak
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Lili
authors.initials: L
authors.lastname: Barad
authors.affiliation: Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.|Department of Pediatric Cardiology, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Avraham
authors.initials: A
authors.lastname: Lorber
authors.affiliation: 'Victor Babes' National Institute of Pathology, Bucharest, Romania.
authors.forename: Mihaela
authors.initials: M
authors.lastname: Gherghiceanu
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Irina
authors.initials: I
authors.lastname: Reiter
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Binyamin
authors.initials: B
authors.lastname: Eisen
authors.affiliation: Department of Plastic Surgery, Rambam Health Care Campus, Haifa, Israel.
authors.forename: Liron
authors.initials: L
authors.lastname: Eldor
authors.affiliation: The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Joseph
authors.initials: J
authors.lastname: Itskovitz-Eldor
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Eldar
authors.affiliation: Leviev Heart Center, Sheba Medical Center, Tel Hashomer and Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Arad
authors.affiliation: Department of Physiology, Technion, Haifa, Israel.|The Rappaport Institute for Research in the Medical Sciences, Technion, Haifa, Israel.|Ruth & Bruce Rappaport Faculty of Medicine, Technion, Haifa, Israel.
authors.forename: Ofer
authors.initials: O
authors.lastname: Binah
mesh_terms: D001483:Base Sequence; D002110:Caffeine / Q000494:pharmacology; D020013:Calcium Signaling / Q000187:drug effects; D002155:Calsequestrin / Q000235:genetics*; D002454:Cell Differentiation / Q000187:drug effects; D060005:Genotyping Techniques; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D007545:Isoproterenol / Q000494:pharmacology; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000473:pathology* / Q000648:ultrastructure; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics*; D012519:Sarcoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D017180:Tachycardia, Ventricular / Q000235:genetics* / Q000473:pathology*; D000098850:Polymorphic Catecholaminergic Ventricular Tachycardia
chemical_list: D002155:Calsequestrin; D019837:Ryanodine Receptor Calcium Release Channel; D002110:Caffeine; D007545:Isoproterenol
keywords: Ca2+ transients; Induced pluripotent stem cells; arrhythmias; cardiomyocytes; catacholaminergic polymorphic ventricular tachycardia