title: Restrictive loss of plakoglobin in cardiomyocytes leads to arrhythmogenic cardiomyopathy.
abstract: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inheritable myocardial disorder associated with fibrofatty replacement of myocardium and ventricular arrhythmia. A subset of ARVC is categorized as Naxos disease, which is characterized by ARVC and a cutaneous disorder. A homozygous loss-of-function mutation of the Plakoglobin (Jup) gene, which encodes a major component of the desmosome and the adherens junction, had been identified in Naxos patients, although the underlying mechanism remained elusive. We generated Jup mutant mice by ablating Jup in cardiomyocytes. Jup mutant mice largely recapitulated the clinical manifestation of human ARVC: ventricular dilation and aneurysm, cardiac fibrosis, cardiac dysfunction and spontaneous ventricular arrhythmias. Ultra-structural analyses revealed that desmosomes were absent in Jup mutant myocardia, whereas adherens junctions and gap junctions were preserved. We found that ventricular arrhythmias were associated with progressive cardiomyopathy and fibrosis in Jup mutant hearts. Massive cell death contributed to the cardiomyocyte dropout in Jup mutant hearts. Despite the increase of β-catenin at adherens junctions in Jup mutant cardiomyoicytes, the Wnt/β-catenin-mediated signaling was not altered. Transforming growth factor-beta-mediated signaling was found significantly elevated in Jup mutant cardiomyocytes at the early stage of cardiomyopathy, suggesting an important pathogenic pathway for Jup-related ARVC. These findings have provided further insights for the pathogenesis of ARVC and potential therapeutic interventions.
authors: Riley Heart Research Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
authors: Deqiang
authors: D
authors: Li
authors: Ying
authors: Y
authors: Liu
authors: Mitsunori
authors: M
authors: Maruyama
authors: Wuqiang
authors: W
authors: Zhu
authors: Hanying
authors: H
authors: Chen
authors: Wenjun
authors: W
authors: Zhang
authors: Sean
authors: S
authors: Reuter
authors: Shien-Fong
authors: SF
authors: Lin
authors: Laura S
authors: LS
authors: Haneline
authors: Loren J
authors: LJ
authors: Field
authors: Peng-Sheng
authors: PS
authors: Chen
authors: Weinian
authors: W
authors: Shou
mesh_terms: D000818:Animals; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000503:physiopathology; D019571:Arrhythmogenic Right Ventricular Dysplasia / Q000150:complications / Q000473:pathology* / Q000503:physiopathology; D016923:Cell Death; D003896:Desmosomes / Q000378:metabolism / Q000648:ultrastructure; D005355:Fibrosis; D017353:Gene Deletion; D006329:Heart Conduction System / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D051379:Mice; D008817:Mice, Mutant Strains; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000473:pathology* / Q000648:ultrastructure; D009928:Organ Specificity; D012518:Sarcomeres / Q000378:metabolism / Q000648:ultrastructure; D060449:Wnt Signaling Pathway; D051185:gamma Catenin / Q000172:deficiency* / Q000378:metabolism
chemical_list: D051185:gamma Catenin