Desmosomal dysfunction due to mutations in desmoplakin causes arrhythmogenic right ventricular dysplasia/cardiomyopathy.

TitleDesmosomal dysfunction due to mutations in desmoplakin causes arrhythmogenic right ventricular dysplasia/cardiomyopathy.
Publication TypeJournal Article
Year of Publication2006
AuthorsYang, Z, Bowles, NE, Scherer, SE, Taylor, MD, Kearney, DL, Ge, S, Nadvoretskiy, VV, DeFreitas, G, Carabello, B, Brandon, LI, Godsel, LM, Green, KJ, Saffitz, JE, Li, H, Danieli, GAntonio, Calkins, H, Marcus, F, Towbin, JA
JournalCirc Res
Volume99
Issue6
Pagination646-55
Date Published2006 Sep 15
ISSN1524-4571
KeywordsAnimals, Apoptosis, Arrhythmogenic Right Ventricular Dysplasia, Cardiomyopathies, Cell Communication, Cell Line, Tumor, Desmoplakins, Desmosomes, DNA Mutational Analysis, Embryo, Mammalian, Heart, Humans, Intercellular Junctions, Lipid Metabolism, Mice, Mice, Transgenic, Mutation, Missense, Myocytes, Cardiac
Abstract

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is characterized by progressive degeneration of the right ventricular myocardium, ventricular arrhythmias, fibrous-fatty replacement, and increased risk of sudden death. Mutations in 6 genes, including 4 encoding desmosomal proteins (Junctional plakoglobin (JUP), Desmoplakin (DSP), Plakophilin 2, and Desmoglein 2), have been identified in patients with ARVD/C. Mutation analysis of 66 probands identified 4 variants in DSP; V30M, Q90R, W233X, and R2834H. To establish a cause and effect relationship between those DSP missense mutations and ARVD/C, we performed in vitro and in vivo analyses of the mutated proteins. Unlike wild-type (WT) DSP, the N-terminal mutants (V30M and Q90R) failed to localize to the cell membrane in desomosome-forming cell line and failed to bind to and coimmunoprecipitate JUP. Multiple attempts to generate N-terminal DSP (V30M and Q90R) cardiac-specific transgenes have failed: analysis of embryos revealed evidence of profound ventricular dilation, which likely resulted in embryonic lethality. We were able to develop transgenic (Tg) mice with cardiac-restricted overexpression of the C-terminal mutant (R2834H) or WT DSP. Whereas mice overexpressing WT DSP had no detectable histologic, morphological, or functional cardiac changes, the R2834H-Tg mice had increased cardiomyocyte apoptosis, cardiac fibrosis, and lipid accumulation, along with ventricular enlargement and cardiac dysfunction in both ventricles. These mice also displayed interruption of DSP-desmin interaction at intercalated discs (IDs) and marked ultra-structural changes of IDs. These data suggest DSP expression in cardiomyocytes is crucial for maintaining cardiac tissue integrity, and DSP abnormalities result in ARVD/C by cardiomyocyte death, changes in lipid metabolism, and defects in cardiac development.

DOI10.1161/01.RES.0000241482.19382.c6
Alternate JournalCirc. Res.
PubMed ID16917092
Grant ListP01-67155 / / PHS HHS / United States
U01-65652 / / PHS HHS / United States