scholarly journals Simultaneous Pathoproteomic Evaluation of the Dystrophin-Glycoprotein Complex and Secondary Changes in the mdx-4cv Mouse Model of Duchenne Muscular Dystrophy

Biology ◽  
2015 ◽  
Vol 4 (2) ◽  
pp. 397-423 ◽  
Author(s):  
Sandra Murphy ◽  
Michael Henry ◽  
Paula Meleady ◽  
Margit Zweyer ◽  
Rustam Mundegar ◽  
...  
Biomolecules ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1206
Author(s):  
Tateki Kikuchi

The etiology of chicken muscular dystrophy is the synthesis of aberrant WW domain containing E3 ubiquitin-protein ligase 1 (WWP1) protein made by a missense mutation of WWP1 gene. The β-dystroglycan that confers stability to sarcolemma was identified as a substrate of WWP protein, which induces the next molecular collapse. The aberrant WWP1 increases the ubiquitin ligase-mediated ubiquitination following severe degradation of sarcolemmal and cytoplasmic β-dystroglycan, and an erased β-dystroglycan in dystrophic αW fibers will lead to molecular imperfection of the dystrophin-glycoprotein complex (DGC). The DGC is a core protein of costamere that is an essential part of force transduction and protects the muscle fibers from contraction-induced damage. Caveolin-3 (Cav-3) and dystrophin bind competitively to the same site of β-dystroglycan, and excessive Cav-3 on sarcolemma will block the interaction of dystrophin with β-dystroglycan, which is another reason for the disruption of the DGC. It is known that fast-twitch glycolytic fibers are more sensitive and vulnerable to contraction-induced small tears than slow-twitch oxidative fibers under a variety of diseased conditions. Accordingly, the fast glycolytic αW fibers must be easy with rapid damage of sarcolemma corruption seen in chicken muscular dystrophy, but the slow oxidative fibers are able to escape from these damages.


2006 ◽  
Vol 290 (2) ◽  
pp. C577-C582 ◽  
Author(s):  
Stefania Assereto ◽  
Silvia Stringara ◽  
Federica Sotgia ◽  
Gloria Bonuccelli ◽  
Aldobrando Broccolini ◽  
...  

In this report, we have developed a novel method to identify compounds that rescue the dystrophin-glycoprotein complex (DGC) in patients with Duchenne or Becker muscular dystrophy. Briefly, freshly isolated skeletal muscle biopsies (termed skeletal muscle explants) from patients with Duchenne or Becker muscular dystrophy were maintained under defined cell culture conditions for a 24-h period in the absence or presence of a specific candidate compound. Using this approach, we have demonstrated that treatment with a well-characterized proteasome inhibitor, MG-132, is sufficient to rescue the expression of dystrophin, β-dystroglycan, and α-sarcoglycan in skeletal muscle explants from patients with Duchenne or Becker muscular dystrophy. These data are consistent with our previous findings regarding systemic treatment with MG-132 in a dystrophin-deficient mdx mouse model (Bonuccelli G, Sotgia F, Schubert W, Park D, Frank PG, Woodman SE, Insabato L, Cammer M, Minetti C, and Lisanti MP. Am J Pathol 163: 1663–1675, 2003). Our present results may have important new implications for the possible pharmacological treatment of Duchenne or Becker muscular dystrophy in humans.


2017 ◽  
Vol 121 (suppl_1) ◽  
Author(s):  
Yuka Morikawa ◽  
Todd Heallen ◽  
John Leach ◽  
Yang Xiao ◽  
James Martin

Regeneration of mammalian heart is limited due to the extremely low renewal rate of cardiomyocytes and their inability to reenter the cell cycle. The Hippo pathway controls heart size during development and represses postnatal heart regeneration by repressing cardiomyocyte proliferation. Our approach for activating adult heart regeneration is to uncover the mechanisms responsible for repression of cardiomyocyte proliferation. We have previously found that deletion of Salv, a modulator of the Hippo pathway, results in myocardial damage repair in postnatal and adult hearts. Deletion of Salv results in activation of the transcription factor, Yap, which positively regulates cytoskeleton and cell cycle genes. We also found that the components of dystrophin glycoprotein complex (DGC) are the target of Yap and DGC regulates heart regeneration. The dystrophin glycoprotein complex (DGC) is essential for muscle maintenance by anchoring the cytoskeleton and extracellular matrix. Disruption of the DGC results in muscular dystrophies, including Duchenne muscular dystrophy, resulting in both skeletal and cardiac myopathies. To explore the connection between DGC and the Hippo pathway, we conditionally deleted Salv in the mdx background, a mouse model of muscular dystrophy. We found that simultaneous disruption of the DGC and the Hippo pathway leads an increased cardiomyocyte proliferation after heart damage. This is associated with increased activity of Yap, suggesting DGC negatively regulate Yap to repress proliferation. We also found that one of the components DGC, dystroglycan directly binds Yap and anchors to the membrane. Our findings provide new insights into the mechanisms leading to heart repair through proliferation of endogenous cardiomyocytes.


2007 ◽  
Vol 17 (4) ◽  
pp. 285-289 ◽  
Author(s):  
Heather MacLeod ◽  
Peter Pytel ◽  
Robert Wollmann ◽  
Ewa Chelmicka-Schorr ◽  
Kenneth Silver ◽  
...  

Author(s):  
Stéphanie Daval ◽  
Chantal Rocher ◽  
Yan Cherel ◽  
Elisabeth Rumeur

AbstractThe dystrophin-glycoprotein complex (DGC) is a large trans-sarcolemmal complex that provides a linkage between the subsarcolemmal cytoskeleton and the extracellular matrix. In skeletal muscle, it consists of the dystroglycan, sarcoglycan and cytoplasmic complexes, with dystrophin forming the core protein. The DGC has been described as being absent or greatly reduced in dystrophin-deficient muscles, and this lack is considered to be involved in the dystrophic phenotype. Such a decrease in the DGC content was observed in dystrophin-deficient muscle from humans with muscular dystrophy and in mice with X-linked muscular dystrophy (mdx mice). These deficits were observed in total muscle homogenates and in partially membrane-purified muscle fractions, the so-called KCl-washed microsomes. Here, we report that most of the proteins of the DGC are actually present at normal levels in the mdx mouse muscle plasma membrane. The proteins are detected in dystrophic animal muscles when the immunoblot assay is performed with crude surface membrane fractions instead of the usually employed KCl-washed microsomes. We propose that these proteins form SDS-insoluble membrane complexes when dystrophin is absent.


2015 ◽  
Vol 117 (suppl_1) ◽  
Author(s):  
Alex C Chang ◽  
Sang-Ging Ong ◽  
Joseph Wu ◽  
Helen M Blau

Duchenne muscular dystrophy (DMD) is a lethal X-linked recessive disease that is result of mutations in the dystrophin gene and is the most common myopathic disease in humans with a prevalence of one in every 3500 males. Dystrophin is crucial for the formation of a dystrophin-glycoprotein complex (DGC), which connects the cytoskeleton of a muscle fiber to the surrounding extracellular matrix in both skeletal and cardiac muscles. In the heart, loss of dystrophin leads to increased fibrosis and death in the third decade of life due to dilated cardiomyopathy. A conundrum in studying and developing therapies for DMD has been the lack of a mouse model that fully recapitulates the clinical phenotype, as mice that lack dystrophin (mdx model), unlike patients, exhibit only mild skeletal muscle defects, essentially no cardiac defects and have a relatively normal lifespan. Our lab reasoned that the difference in the manifestation of the disease in mice and humans could be telomere length, as mice have substantially longer telomeres than humans. We created a novel mouse model with shortened telomere lengths (similar to humans) that fully recapitulates the skeletal muscle (Cell. 2010;143:1059-1071; the mdx/mTRKO model) and cardiac muscle phenotype of DMD (Nat Cell Biol. 2013; 15:895-904; dilated cardiomyopathy). Interestingly, we observed a relative 45% reduction in cardiomyocyte telomere length in our mdx/mTRKO animals (3 animals per group, N = 300-400) as well as patient samples (4 DMD patient samples, N = 40-95). Here we present new evidence of mitochondrial dysfunction and telomere dysfunction.


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