Duchenne muscular dystrophy (DMD) is caused by mutations in dystrophin and the subsequent disruption of the dystrophin-associated protein complex (DAPC). Utrophin is a dystrophin homolog expressed at high levels in developing muscle that is an attractive target for DMD therapy. Here we show that the extracellular matrix protein biglycan regulates utrophin expression in immature muscle and that recombinant human biglycan (rhBGN) increases utrophin expression in cultured myotubes. Systemically delivered rhBGN up-regulates utrophin at the sarcolemma and reduces muscle pathology in the mdx mouse model of DMD. RhBGN treatment also improves muscle function as judged by reduced susceptibility to eccentric contraction-induced injury. Utrophin is required for the rhBGN therapeutic effect. Several lines of evidence indicate that biglycan acts by recruiting utrophin protein to the muscle membrane. RhBGN is well tolerated in animals dosed for as long as 3 months. We propose that rhBGN could be a therapy for DMD.
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http://dx.doi.org/10.1073/pnas.1013067108 | DOI Listing |
Med
April 2023
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA. Electronic address:
Background: Utrophin, a dystrophin homolog, is consistently upregulated in muscles of patients with Duchenne muscular dystrophy (DMD) and is believed to partially compensate for the lack of dystrophin in dystrophic muscle. Even though several animal studies support the idea that utrophin can modulate DMD disease severity, human clinical data are scarce.
Methods: We describe a patient with the largest reported in-frame deletion in the DMD gene, including exons 10-60 and thus encompassing the entire rod domain.
Skelet Muscle
January 2023
Department of Integrative Biology and Physiology, University of California, Los Angeles, CA, 90095, USA.
Background: The dystrophin-glycoprotein complex (DGC) is a critical adhesion complex of the muscle cell membrane, providing a mechanical link between the extracellular matrix (ECM) and the cortical cytoskeleton that stabilizes the sarcolemma during repeated muscle contractions. One integral component of the DGC is the transmembrane protein, sarcospan (SSPN). Overexpression of SSPN in the skeletal muscle of mdx mice (murine model of DMD) restores muscle fiber attachment to the ECM in part through an associated increase in utrophin and integrin adhesion complexes at the cell membrane, protecting the muscle from contraction-induced injury.
View Article and Find Full Text PDFJ Biol Chem
February 2023
Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota - Twin Cities, Minneapolis, MN, USA. Electronic address:
Duchenne muscular dystrophy is a lethal muscle wasting disease caused by the absence of the protein dystrophin. Utrophin is a dystrophin homologue currently under investigation as a protein replacement therapy for Duchenne muscular dystrophy. Dystrophin is hypothesized to function as a molecular shock absorber that mechanically stabilizes the sarcolemma.
View Article and Find Full Text PDFMethods Mol Biol
November 2022
Department of Cellular and Molecular Medicine, and the Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada.
Duchenne muscular dystrophy (DMD) is a neuromuscular disease caused by mutations and deletions within the DMD gene, which result in a lack of dystrophin protein at the sarcolemma of skeletal muscle fibers. The absence of dystrophin fragilizes the sarcolemma and compromises its integrity during cycles of muscle contraction, which, progressively, leads to reductions in muscle mass and function. DMD is thus a progressive muscle-wasting disease that results in a loss of ambulation, cardiomyopathy , respiratory impairment, and death.
View Article and Find Full Text PDFFundam Res
November 2022
State Key Laboratory of Primate Biomedical Research & Institute of Primate Translational Medicine, Kunming University of Science and Technology, Kunming 650500, China.
Duchenne muscular dystrophy (DMD) is a serious genetic neuromuscular rare disease that is prevalent and caused by the mutation/deletion of the X-linked DMD gene that encodes dystrophin. Utrophin is a dystrophin homologous protein on human chromosome 6. Dystrophin and utrophin are highly homologous.
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