title: In vitro modeling of ryanodine receptor 2 dysfunction using human induced pluripotent stem cells.
abstract: OBJECTIVE
  Induced pluripotent stem (iPS) cells generated from accessible adult cells of patients with genetic diseases open unprecedented opportunities for exploring the pathophysiology of human diseases in vitro. Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is an inherited cardiac disorder that is caused by mutations in the cardiac ryanodine receptor type 2 gene (RYR2) and is characterized by stress-induced ventricular arrhythmia that can lead to sudden cardiac death in young individuals. The aim of this study was to generate iPS cells from a patient with CPVT1 and determine whether iPS cell-derived cardiomyocytes carrying patient specific RYR2 mutation recapitulate the disease phenotype in vitro.
  
  
  METHODS
  iPS cells were derived from dermal fibroblasts of healthy donors and a patient with CPVT1 carrying the novel heterozygous autosomal dominant mutation p.F2483I in the RYR2. Functional properties of iPS cell derived-cardiomyocytes were analyzed by using whole-cell current and voltage clamp and calcium imaging techniques.
  
  
  RESULTS
  Patch-clamp recordings revealed arrhythmias and delayed afterdepolarizations (DADs) after catecholaminergic stimulation of CPVT1-iPS cell-derived cardiomyocytes. Calcium imaging studies showed that, compared to healthy cardiomyocytes, CPVT1-cardiomyocytes exhibit higher amplitudes and longer durations of spontaneous Ca(2+) release events at basal state. In addition, in CPVT1-cardiomyocytes the Ca(2+)-induced Ca(2+)-release events continued after repolarization and were abolished by increasing the cytosolic cAMP levels with forskolin.
  
  
  CONCLUSIONS
  This study demonstrates the suitability of iPS cells in modeling RYR2-related cardiac disorders in vitro and opens new opportunities for investigating the disease mechanism in vitro, developing new drugs, predicting their toxicity, and optimizing current treatment strategies.
authors.affiliation: Institute for Neurophysiology, University of Cologne, Robert Koch Strasse 39, Cologne, Germany.
authors.forename: Azra
authors.initials: A
authors.lastname: Fatima
authors.forename: Guoxing
authors.initials: G
authors.lastname: Xu
authors.forename: Kaifeng
authors.initials: K
authors.lastname: Shao
authors.forename: Symeon
authors.initials: S
authors.lastname: Papadopoulos
authors.forename: Martin
authors.initials: M
authors.lastname: Lehmann
authors.forename: Juan J
authors.initials: JJ
authors.lastname: Arnáiz-Cot
authors.forename: Angelo O
authors.initials: AO
authors.lastname: Rosa
authors.forename: Filomain
authors.initials: F
authors.lastname: Nguemo
authors.forename: Matthias
authors.initials: M
authors.lastname: Matzkies
authors.forename: Sven
authors.initials: S
authors.lastname: Dittmann
authors.forename: Susannah L
authors.initials: SL
authors.lastname: Stone
authors.forename: Matthias
authors.initials: M
authors.lastname: Linke
authors.forename: Ulrich
authors.initials: U
authors.lastname: Zechner
authors.forename: Vera
authors.initials: V
authors.lastname: Beyer
authors.forename: Hans Christian
authors.initials: HC
authors.lastname: Hennies
authors.forename: Stephan
authors.initials: S
authors.lastname: Rosenkranz
authors.forename: Baerbel
authors.initials: B
authors.lastname: Klauke
authors.forename: Abdul S
authors.initials: AS
authors.lastname: Parwani
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Haverkamp
authors.forename: Gabriele
authors.initials: G
authors.lastname: Pfitzer
authors.forename: Martin
authors.initials: M
authors.lastname: Farr
authors.forename: Lars
authors.initials: L
authors.lastname: Cleemann
authors.forename: Martin
authors.initials: M
authors.lastname: Morad
authors.forename: Hendrik
authors.initials: H
authors.lastname: Milting
authors.forename: Juergen
authors.initials: J
authors.lastname: Hescheler
authors.forename: Tomo
authors.initials: T
authors.lastname: Saric
mesh_terms: D000200:Action Potentials; D002118:Calcium / Q000378:metabolism; D002395:Catecholamines / Q000378:metabolism; D002454:Cell Differentiation; D005576:Colforsin / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism; D004562:Electrocardiography; D006579:Heterozygote; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000166:cytology / Q000378:metabolism*; D007621:Karyotyping; D008954:Models, Biological; D009154:Mutation; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010641:Phenotype; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*; D017180:Tachycardia, Ventricular / Q000378:metabolism / Q000473:pathology; D000098850:Polymorphic Catecholaminergic Ventricular Tachycardia
chemical_list: D002395:Catecholamines; D019837:Ryanodine Receptor Calcium Release Channel; D005576:Colforsin; D000242:Cyclic AMP; D002118:Calcium