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Nederlands Tijdschrift Voor Geneeskunde Feb 2002Duchenne and Becker muscular dystrophy (DMD and BMD) are progressive disorders, which almost exclusively affect males. DMD is the more severe type with an onset at 2-3... (Review)
Review
Duchenne and Becker muscular dystrophy (DMD and BMD) are progressive disorders, which almost exclusively affect males. DMD is the more severe type with an onset at 2-3 years of age. Patients become wheelchair-bound before the age of 13 and often die due to cardiac arrest or respiratory insufficiency. BMD, a more varying phenotype which may overlap with limb girdle muscular dystrophy (LGMD), has a less severe muscle weakness which starts later than in DMD patients. DMD carriers may show some muscle weakness. The dystrophin gene (2.4 Mb), known to be involved in DMD/BMD, codes for a 427 kilodalton muscle-specific protein named dystrophin as well as several tissue-specific isoforms. Dystrophin, as part of a membrane-bound complex of proteins, connects the cytoskeleton of the muscle cell to the extracellular matrix. Since 1985, when highly reliable carrier detection and prenatal diagnosis at the DNA level became possible, over 250 prenatal tests have been performed. Molecular genetic analysis, highlighted a phenomenon called germinal mosaicism, which explains the recurrence of de novo mutations and led to the discovery of the so-called reading-frame rule, which helps to discriminate between DMD and BMD. Fifteen years after the discovery of the dystrophin gene, mutations can be detected in 95% of the patients, while the remaining 5% are still hiding within this very large gene.
Topics: Chromosome Mapping; DNA Mutational Analysis; Dystrophin; Female; Humans; Male; Muscular Dystrophy, Duchenne; Mutation; Sex Characteristics
PubMed: 11887623
DOI: No ID Found -
Lancet (London, England) Mar 2002
Topics: Animals; Cytoskeletal Proteins; Dystrophin; Heart Failure; Humans; Membrane Proteins; Sarcolemma; Signal Transduction; Utrophin
PubMed: 11918903
DOI: 10.1016/S0140-6736(02)08013-3 -
Proceedings of the National Academy of... Apr 2014Dystrophin and utrophin are highly similar proteins that both link cortical actin filaments with a complex of sarcolemmal glycoproteins, yet localize to different... (Comparative Study)
Comparative Study
Dystrophin and utrophin are highly similar proteins that both link cortical actin filaments with a complex of sarcolemmal glycoproteins, yet localize to different subcellular domains within normal muscle cells. In mdx mice and Duchenne muscular dystrophy patients, dystrophin is lacking and utrophin is consequently up-regulated and redistributed to locations normally occupied by dystrophin. Transgenic overexpression of utrophin has been shown to significantly improve aspects of the disease phenotype in the mdx mouse; therefore, utrophin up-regulation is under intense investigation as a potential therapy for Duchenne muscular dystrophy. Here we biochemically compared the previously documented microtubule binding activity of dystrophin with utrophin and analyzed several transgenic mouse models to identify phenotypes of the mdx mouse that remain despite transgenic utrophin overexpression. Our in vitro analyses revealed that dystrophin binds microtubules with high affinity and pauses microtubule polymerization, whereas utrophin has no activity in either assay. We also found that transgenic utrophin overexpression does not correct subsarcolemmal microtubule lattice disorganization, loss of torque production after in vivo eccentric contractions, or physical inactivity after mild exercise. Finally, our data suggest that exercise-induced inactivity correlates with loss of sarcolemmal neuronal NOS localization in mdx muscle, whereas loss of in vivo torque production after eccentric contraction-induced injury is associated with microtubule lattice disorganization.
Topics: Animals; Dystrophin; Fluorescence; Mice; Mice, Transgenic; Microtubules; Muscle Contraction; Muscle, Skeletal; Torque; Utrophin
PubMed: 24706788
DOI: 10.1073/pnas.1323842111 -
Biophysical Journal Oct 2018Scaffolding proteins play important roles in supporting the plasma membrane (sarcolemma) of muscle cells. Among them, dystrophin strengthens the sarcolemma through...
Scaffolding proteins play important roles in supporting the plasma membrane (sarcolemma) of muscle cells. Among them, dystrophin strengthens the sarcolemma through protein-lipid interactions, and its absence due to gene mutations leads to the severe Duchenne muscular dystrophy. Most of the dystrophin protein consists of a central domain made of 24 spectrin-like coiled-coil repeats (R). Using small angle neutron scattering (SANS) and the contrast variation technique, we specifically probed the structure of the three first consecutive repeats 1-3 (R1-3), a part of dystrophin known to physiologically interact with membrane lipids. R1-3 free in solution was compared to its structure adopted in the presence of phospholipid-based bicelles. SANS data for the protein/lipid complexes were obtained with contrast-matched bicelles under various phospholipid compositions to probe the role of electrostatic interactions. When bound to anionic bicelles, large modifications of the protein three-dimensional structure were detected, as revealed by a significant increase of the protein gyration radius from 42 ± 1 to 60 ± 4 Å. R1-3/anionic bicelle complexes were further analyzed by coarse-grained molecular dynamics simulations. From these studies, we report an all-atom model of R1-3 that highlights the opening of the R1 coiled-coil repeat when bound to the membrane lipids. This model is totally in agreement with SANS and click chemistry/mass spectrometry data. We conclude that the sarcolemma membrane anchoring that occurs during the contraction/elongation process of muscles could be ensured by this coiled-coil opening. Therefore, understanding these structural changes may help in the design of rationalized shortened dystrophins for gene therapy. Finally, our strategy opens up new possibilities for structure determination of peripheral and integral membrane proteins not compatible with different high-resolution structural methods.
Topics: Dystrophin; Humans; Membrane Lipids; Micelles; Molecular Dynamics Simulation; Protein Binding; Protein Conformation, alpha-Helical
PubMed: 30197181
DOI: 10.1016/j.bpj.2018.07.039 -
Journal of the Peripheral Nervous... 1997
Review
Topics: Animals; Dystrophin; Humans; Multigene Family; Muscle, Skeletal; Nervous System
PubMed: 10959226
DOI: No ID Found -
Muscle & Nerve Aug 1998Golden retriever muscular dystrophy (GRMD), the canine model of Duchenne muscular dystrophy (DMD), is caused by a splice site mutation in the dystrophin gene. This...
Golden retriever muscular dystrophy (GRMD), the canine model of Duchenne muscular dystrophy (DMD), is caused by a splice site mutation in the dystrophin gene. This mutation predicts a premature termination codon in exon 8 and a peptide that is 5% the size of normal dystrophin. Western blot analysis of skeletal muscle from GRMD dogs reveals a slightly truncated 390-kD protein that is approximately 91% the size of normal dystrophin. This 390-kD dystrophin suggests that GRMD dogs, like some DMD patients, employ a mechanism to overcome their predicted frameshift. Reverse-transcriptase polymerase chain reaction on GRMD muscle has revealed two in-frame dystrophin transcripts which lack either exons 3-9 or exons 5-12. Both transcripts could be translated into a dystrophin protein of approximately 390 kD. An understanding of how truncated dystrophin is produced in GRMD may allow this mechanism to be manipulated toward a potential therapy for DMD.
Topics: Alternative Splicing; Animals; Antibodies, Monoclonal; Base Sequence; Blotting, Western; DNA Mutational Analysis; Disease Models, Animal; Dogs; Dystrophin; Exons; Molecular Sequence Data; Muscle, Skeletal; Muscular Dystrophies; Muscular Dystrophy, Animal; Phenotype; Polymerase Chain Reaction; Transcription, Genetic
PubMed: 9655116
DOI: 10.1002/(sici)1097-4598(199808)21:8<991::aid-mus2>3.0.co;2-0 -
Neurotherapeutics : the Journal of the... Oct 2023Duchenne muscular dystrophy (DMD) is the most common childhood form of muscular dystrophy. It is caused by mutations in the DMD gene, leading to reduced or absent... (Review)
Review
Duchenne muscular dystrophy (DMD) is the most common childhood form of muscular dystrophy. It is caused by mutations in the DMD gene, leading to reduced or absent expression of the dystrophin protein. Clinically, this results in loss of ambulation, cardiomyopathy, respiratory failure, and eventually death. In the past decades, the use of corticosteroids has slowed down the disease progression. More recently, the development of genetically mediated therapies has emerged as the most promising treatment for DMD. These strategies include exon skipping with antisense oligonucleotides, gene replacement therapy with adeno-associated virus, and gene editing with CRISPR (clustered regularly interspaced short palindromic repeats) technology. In this review, we highlight the most up-to-date therapeutic progresses in the field, with emphasis on past and recent experiences, as well as the latest clinical results of DMD micro-dystrophin gene therapy. Additionally, we discuss the lessons learned along the way and the challenges encountered, all of which have helped advance the field, with the potential to finally alleviate such a devastating disease.
Topics: Humans; Child; Muscular Dystrophy, Duchenne; Dystrophin; Gene Editing; Exons; Genetic Therapy
PubMed: 37673849
DOI: 10.1007/s13311-023-01423-y -
Brain Pathology (Zurich, Switzerland) Jan 1996
Review
Topics: Animals; Dystrophin; Humans; Muscle Proteins; Muscular Dystrophy, Animal
PubMed: 8866744
DOI: 10.1111/j.1750-3639.1996.tb00779.x -
Human Gene Therapy. Clinical Development Mar 2016After years of relentless efforts, gene therapy has now begun to deliver its therapeutic promise in several diseases. A number of gene therapy products have received...
After years of relentless efforts, gene therapy has now begun to deliver its therapeutic promise in several diseases. A number of gene therapy products have received regulatory approval in Europe and Asia. Duchenne muscular dystrophy (DMD) is an X-linked inherited lethal muscle disease. It is caused by mutations in the dystrophin gene. Replacing and/or repairing the mutated dystrophin gene holds great promises to treated DMD at the genetic level. Last several years have evidenced significant developments in preclinical experimentations in murine and canine models of DMD. There has been a strong interest in moving these promising findings to clinical trials. In light of rapid progress in this field, the Parent Project Muscular Dystrophy (PPMD) recently interviewed me on the current status of DMD gene therapy and readiness for clinical trials. Here I summarized the interview with PPMD.
Topics: Animals; Dogs; Dystrophin; Genetic Therapy; Humans; Mice; Muscular Dystrophy, Duchenne
PubMed: 27003751
DOI: 10.1089/humc.2016.001 -
Histochemistry and Cell Biology Sep 2016The dystrophin gene consists of 79 exons and encodes tissue-specific isoforms. Mutations in the dystrophin gene cause Duchenne muscular dystrophy, of which a substantial...
The dystrophin gene consists of 79 exons and encodes tissue-specific isoforms. Mutations in the dystrophin gene cause Duchenne muscular dystrophy, of which a substantial proportion of cases are complicated by non-progressive mental retardation. Abnormalities of Dp71, an isoform transcribed from a promoter in intron 62, are a suspected cause of mental retardation. However, the roles of Dp71 in human brain have not been fully elucidated. Here, we characterized dystrophin in human HEK293 cells with the neuronal lineage. Reverse transcription-PCR amplification of the full-length dystrophin transcript revealed the absence of fragments covering the 5' part of the dystrophin cDNA. In contrast, fragments covering exons 64-79 were present. The Dp71 promoter-specific exon G1 was shown spliced to exon 63. We demonstrated that the Dp71 transcript comprised two subisoforms: one lacking exon 78 (Dp71b) and the other lacking both exons 71 and 78 (Dp71ab). Western blotting of cell lysates using an antibody against the dystrophin C-terminal region revealed two bands, corresponding to Dp71b and Dp71ab. Immunohistochemical examination with the dystrophin antibody revealed scattered punctate signals in the cytoplasm and the nucleus. Western blotting revealed one band corresponding to Dp71b in the cytoplasm and two bands corresponding to Dp71b and Dp71ab in the nucleus, with Dp71b being predominant. These results indicated that Dp71ab is a nucleus-specific subisoform. We concluded that Dp71, comprising Dp71b and Dp71ab, was expressed exclusively in HEK293 cells and that Dp71ab was specifically localized to the nucleus. Our findings suggest that Dp71ab in the nucleus contributes to the diverse functions of HEK293 cells.
Topics: Cell Nucleus; Dystrophin; HEK293 Cells; Humans; Protein Isoforms
PubMed: 27109495
DOI: 10.1007/s00418-016-1439-2