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LINK : Duchenne muscular dystrophy (DMD) is caused by mutations in the gene that encodes the 427-kDa cytoskeletal protein dystrophin. Increased knowledge of the function of dystrophin and its role in muscle has led to a greater understanding of the pathogenesis of DMD. This, together with advances in the genetic toolkit of the molecular biologist, are leading to many different approaches to treatment. Gene therapy can be achieved using plasmids or viruses, mutations can be corrected using chimaeraplasts and short DNA fragments, exon skipping of mutations can be induced using oligonucleotides and readthrough of nonsense mutations can be achieved using aminoglycoside antibiotics. Blocking the proteasome degradation pathway can stabilize any truncated dystrophin protein, and upregulation of other proteins can also prevent the dystrophic process. Muscle can be repopulated with myoblasts or stem cells. All, or a combination, of these approaches hold great promise for the treatment of this devastating disease. |
LINK The last decade has evidenced unprecedented progress in gene therapy of Duchenne and Becker muscular dystrophy (DMD and BMD) skeletal muscle disease. Cardiomyopathy is a leading cause of morbidity and mortality in both patients and carriers of DMD, BMD and X-linked dilated cardiomyopathy. However, there is little advance in heart gene therapy. The gene, the vector, vector delivery, the target tissue and animal models are five fundamental components in developing an effective gene therapy. Intensive effort has been made in optimizing gene transfer vectors and methods. Systemic and/or local delivery of recombinant adeno-associated viral vector have resulted in widespread transduction in the rodent heart. The current challenge is to define other parameters that are essential for a successful gene therapy such as the best candidate gene(s), the optimal expression level and the target tissue. This review focuses on these long-ignored aspects and points out future research directions. In particular, we need to address whether all or only some of the recently developed mini- and microgenes are protective in the heart |
LINK The dystrophin glycoprotein complex (DGC) is a specialization of cardiac and skeletal muscle membrane. This large multicomponent complex has both mechanical stabilizing and signaling roles in mediating interactions between the cytoskeleton, membrane, and extracellular matrix. Dystrophin, the protein product of the Duchenne and X-linked dilated cardiomyopathy locus, links cytoskeletal and membrane elements. Mutations in additional DGC genes, the sarcoglycans, also lead to cardiomyopathy and muscular dystrophy. Animal models of DGC mutants have shown that destabilization of the DGC leads to membrane fragility and loss of membrane integrity, resulting in degeneration of skeletal muscle and cardiomyocytes. Vascular reactivity is altered in response to primary degeneration in striated myocytes and arises from a vascular smooth muscle cell–extrinsic mechanism. |
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