Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “DMD”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 991 records · Page 55Linked to original sources
PubMed1998

Transplantation of dermal fibroblasts expressing MyoD1 in mouse muscles.

Transplantation of normal myoblasts into dystrophic muscles is a potential treatment for Duchenne muscular dystrophy (DMD). However, the success of such grafts is limited by the immune system responses. To avoid rejection problems, autologous transplantation of the patient's corrected myoblasts has been proposed. Regretfully, the low proliferative capacity of DMD myoblasts in culture (due to their premature senescence) limits such procedure. On the other hand, modification of dermal fibroblasts leading to the myogenic pathway using a master regulatory gene for myogenesis is an interesting alternative approach. In this study, the retrovirally encoded MyoD1 cDNA was introduced in dermal fibroblasts of TnI LacZ mice to provoke their conversion into myoblast-like cells. In vitro and in vivo assays were done and the results were compared to those obtained with uninfected fibroblasts and myoblasts. Some MyoD1-expressing fibroblasts were able to fuse and to express beta-galactosidase (under the transcriptional control of the Troponin I promoter), dystrophin and desmin in vitro. Thirty days following implantation of these modified fibroblasts in muscles of mdx mice, an average of 7 beta-Gal+/Dys-muscle fibers were observed. No beta-Gal+ fibers were observed after the transplantation of uninfected fibroblasts. Our results indicate that the successful implantation of myoblasts obtained from genetically modified fibroblasts is indeed feasible. However, the in vitro conversion rate and the in vivo fusion of genetically modified fibroblasts must be largely increased to consider this approach as a potential therapy for DMD and other myopathies.

Animals↗
PubMed1999

Increased number of caveolae and caveolin-3 overexpression in Duchenne muscular dystrophy.

Caveolae are small pockets or invaginations localized at the plasma membrane. Caveolins are the principal protein components of caveolae and play an important structural role in the formation of caveolae membranes. Here, we studied by freeze fracture and immunological techniques the spatial organization of caveolae at the muscle cell plasma membrane and the expression of caveolin-3 in Duchenne muscular dystrophy (DMD) muscle fibers. In DMD muscle, we found an increased number of caveolae at the sarcolemma that corresponds to an overexpression of caveolin-3 by immunohistochemistry and by Western blot analysis. These findings suggest a possible role for caveolae and caveolin-3 in the pathogenesis of DMD.

Adolescent↗
PubMed2001

Dystrophin in adult zebrafish muscle.

Mutations in the human dystrophin gene are implicated in the fatal muscle wasting disease Duchenne Muscular Dystrophy (DMD). This gene expresses a sarcolemmal-associated protein that is evolutionarily conserved, underpinning its important role in the architecture of muscle. In terms of DMD modelling, the mouse has served as a suitable vertebrate species but the pathophysiology of the disease in the mouse does not entirely mimic human DMD. We have examined the zebrafish in order to expand the repertoire of vertebrate species for muscle disease modelling, and to dissect further the functional interactions of dystrophin. We report here the identification of an apparent zebrafish orthologue of the human dystrophin gene that expresses a 400-kDa protein that is localised to the muscle membrane surface. These data suggest that the zebrafish may prove to be a beneficial vertebrate model to examine the role and functional interactions of dystrophin in disease and development.

Amino Acid Sequence↗
PubMed2001

Forced myofiber regeneration promotes dystrophin gene transfer and improved muscle function despite advanced disease in old dystrophic mice.

Duchenne muscular dystrophy (DMD) is caused by defects in the dystrophin gene. In young dystrophic mdx mice, immature regenerating myofibers represent the principal substrate for adenovirus vector (AdV)-mediated dystrophin gene transfer. However, in DMD patients immature regenerating myofibers are generally sparse. Such a situation also exists in old mdx mice, which may represent a more realistic model. Therefore, here we have used old mdx mice (of 14- to 17 months of age) to test the hypothesis that one-time administration of a myonecrotic agent can transiently re-establish a population of immature myofibers susceptible to AdV-mediated dystrophin gene transfer. This strategy led to upregulation of the coxsackie/adenovirus attachment receptor by means of induction of regenerating myofibers, significantly augmented AdV-mediated dystrophin gene expression, and enhanced force-generating capacity. In addition, it led to an increased resistance to contraction-induced injury compared with untreated controls. The latter protective effect was positively correlated with the number of dystrophin-expressing myofibers (r=0.83, P<0.05). Accordingly, the risk:benefit ratio associated with the sequential use of forced myofiber regeneration and AdV-mediated dystrophin gene transfer was favorable in old mdx mice despite advanced disease. These findings have implications for the potential applicability of AdV-mediated gene therapy to DMD and other muscle diseases in which immature regenerating myofibers are lacking.

Adenoviridae↗
PubMed1998

The dystrophinopathies: an alternative to the structural hypothesis.

Abnormal expression of the cytoskeletal protein dystrophin has deleterious consequences for skeletal muscle, cardiac muscle, and the central nervous system. A complete failure to express the protein produces Duchenne muscular dystrophy (DMD), in which there is extensive and progressive skeletal muscle necrosis, the development of a life-threatening dilated cardiomyopathy, and mild mental retardation. Dystrophin binds the F-actin cytoskeleton and is normally expressed in a complex of transmembrane proteins (the "dystrophin protein complex") that interact with external components of the basal lamina. One pathogenic model for DMD (the "structural hypothesis") suggests that this complex forms a structural bridge between the external basal lamina and the internal cytoskeleton and that the absence of dystrophin produces a defect in membrane structural support that renders skeletal muscle susceptible to plasmalemmal ruptures (or "tears") during the course of contractile activity. This review attempts to critically evaluate the structural hypothesis for DMD and presents an opposing model (the "channel aggregation model") that highlights the role of dystrophin in organizing the membrane cytoskeleton and the role of the cytoskeleton in aggregating ion channels and neurotransmitter receptors. Since ion channel aggregation is a process that is common across organ systems, the idea that channel function can be altered when aggregated ion channels interact with a dystrophic cytoskeleton has immediate implications for the expression of the dystrophinopathies in skeletal muscle, cardiac muscle, and the central nervous system.

Animals↗
PubMed2006

Redirecting splicing to address dystrophin mutations: molecular by-pass surgery.

Mutations in the dystrophin gene that prevent synthesis of a functional protein lead to Duchenne muscular dystrophy (DMD), the most common serious childhood muscular dystrophy. The major isoform is produced in skeletal muscle and the size of the dystrophin gene and complexity of expression have posed great challenges to the development of a therapy for DMD. Considerable progress has been made in the areas of gene and cell replacement, yet it appears that any potential therapy for DMD is still some years away. Other approaches are being considered, and one that has generated substantial interest over the last few years is induced exon skipping. Antisense oligonucleotides have been used to block abnormal splice sites and force pre-mRNA processing back to the normal patterns. This approach is re-interpreted to address the more common dystrophin mutations, where normal splice sites are targeted to induce abnormal splicing, resulting in specific exon exclusion. Selected exon removal during processing of the dystrophin pre-mRNA can by-pass nonsense mutations or restore a disrupted reading frame arising from genomic deletions or duplications. Attributes of the dystrophin gene that have hampered gene replacement therapy may be regarded as positive features for induced exon skipping, which may be regarded as a form of by-pass surgery at the molecular level. In humans, antisense oligonucleotides have been more generally applied to down-regulate specific gene expression, for the treatment of acquired conditions such as malignancies and viral infections. From interesting in vitro experiments several years ago, the dystrophin exon-skipping field has progressed to the stage of planning for clinical trials.

Alternative Splicing↗
PubMed1992

Parental origin and germline mosaicism of deletions and duplications of the dystrophin gene: a European study.

Knowledge about the parental origin of new mutations and the occurrence of germline mosaicism is important for estimating recurrence risks in Duchenne (DMD) and Becker muscular dystrophy (BMD). However, there are problems in resolving these issues partly because not all mutations can as yet be directly detected, and additionally because genetic ratios are very sensitive to ascertainment bias. In the present study, therefore, analysis was restricted to currently detectable mutations (deletions and duplications) in particular types of families which tend to be rare. In order to obtain sufficient data we pooled results from 25 European centers. In mothers of affected patients who were the first in their family with a dystrophin gene deletion or duplication, the ratio between the paternal and the maternal origin of this new mutation was 32:49 (binomial test P = 0.075) for DMD. In five BMD families the ratio between paternal and maternal origin of new mutations was 3:2. Recurrence risk because of maternal germline mosaicism was studied in sisters or subsequent sibs of isolated cases with an apparently new detectable mutation. In 12 out of 59 (0.20; 95% CI 0.10-0.31) transmissions of the risk haplotype the DMD mutation was transmitted as well. No recurrences were found in nine BMD families.

Chromosome Deletion↗
PubMed1990

Germinal mosaicism from grand-paternal origin in a family with Duchenne muscular dystrophy.

We have identified a Duchenne muscular dystrophy (DMD) pedigree with an unexpected pattern of inheritance. Using marker restriction fragment length polymorphisms detected by probes that lie within and outside the DMD gene, we could demonstrate that the maternal grandfather has transmitted two distinct types of X chromosomes to his offspring. This original observation may be explained by postulating that the DMD mutation must have occurred during mitosis in early germline proliferation, leading to a germline mosaicism within this male ancestor.

DNA Probes↗
PubMed1991

Human dystrophin gene transfer: production and expression of a functional recombinant DNA-based gene.

The identification and cloning of the gene responsible for Duchenne muscular dystrophy (DMD) and characterization of the protein product of the gene, dystrophin, has led to major advances in diagnostic and genetic counselling procedures for this inherited disorder. Due to its high mutation rate, however, individuals affected by DMD will continue to arise in large proportion by de novo mutations, and the search for direct therapies remains a high priority. In this respect direct genetic correction of dystrophin deficiency via grafting of healthy myoblast stem cells or direct introduction of functional DNA into diseased muscle tissue have both been proposed as potential therapeutic approaches. We describe here, the first example of the engineering and cloning of a synthetic gene encoding recombinant human dystrophin and its stable transfer to and expression in mammalian cells. This DMD gene construction represents a primary step towards evaluating direct DNA-mediated gene transfer as a potential treatment for this debilitating disorder.

3T3 Cells↗
PubMed1991

Expression of a dystrophin-related protein associated with the skeletal muscle cell membrane.

We previously reported that a protein which has immunological cross-reactivity with and a molecular weight similar to dystrophin, the Duchenne muscular dystrophy (DMD) gene product, is expressed on the muscle cell membrane (Tanaka et al. 1989b). To examine if this is the translation product of the autosomal transcript with homology to dystrophin mRNA identified by Love et al. (1989), we raised an antibody (PDRP) against a synthetic peptide corresponding to the putative protein (DRP) and examined its expression and cellular localization in human and murine skeletal muscle samples. In immunoblotting, PDRP stained a band with a similar molecular weight to dystrophin in samples from DMD and Becker muscular dystrophy (BMD) patients and control (non-DMD/BMD) human. PDRP was expected not to cross-react with dystrophin because the antigenic peptide was not homologous to dystrophin. In fact, PDRP did not cross-react with dystrophin present in a BMD patient. Immunohistochemically, PDRP stained the muscle cell membrane in samples from DMB and BMD patients and from mdx mice. Only a slight staining was observed in muscles from control human and wild type mice. Our results confirm the presence of DRP in human and murine skeletal muscles, and further demonstrate that it is localized on the cell membrane. The abundance of DRP in dystrophin deficient muscles might be related to some compensatory mechanisms.

Amino Acid Sequence↗
PubMed1986

Estimation of the male to female ratio of mutation rates from the segregation of X-chromosomal DNA haplotypes in Duchenne muscular dystrophy families.

A novel procedure is presented to estimate the ratio of male to female mutation rates for Duchenne muscular dystrophy (DMD). X-specific restriction fragment length polymorphisms are used to establish DNA haplotypes in three-generation DMD families. From the proportion of DMD patients who have inherited their maternal grandfather's X chromosome, the ratio of mutation rates can be calculated. In contrast to classical methods, the proposed procedure is not restricted to sporadic or familiar cases nor is any information on the carrier status of female relatives required.

DNA↗
PubMed1989

Impairment of capping in lymphoblastoid cell lines of Duchenne patients indicates an intrinsic cellular defect.

Duchenne muscular dystrophy (DMD) is a lethal sex-linked degenerative disorder of the muscle in man. Generalized cell membrane abnormalities seem to be involved in the pathogenesis of the disease; in particular, the impairment of lymphocyte capping capacities has been repeatedly confirmed. To clarify whether capping impairment is a consequence of factors related to the activity of the disease or an expression of an intrinsic cellular defect, we have investigated the capping capacities of DMD EBV-transformed cell lines. The results indicate a significant impairment of capping capacity in cultured cell lines, providing evidence for an intrinsic cell deficiency in DMD.

Antibodies, Monoclonal↗
PubMed1983

Genetic linkage relationship between the Xg blood group system and two X chromosome DNA polymorphisms in families with Duchenne and Becker muscular dystrophy.

The existence of linkage has been investigated between the Xg blood group system, two DNA restriction fragment length polymorphisms (RFLPs) located on the short arm of the X chromosome, Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD). No linkage was found between the Xg locus and the more proximal RFLP (L 1.28); close linkage between Xg and the more distal RFLP (lambda RC8) was also excluded. Both RFLPs show linkage with DMD but are not closely linked with each other. Analyses of 11 families with DMD and ten with BMD, informative for the Xg blood group, reinforce the conclusions of others that there is no measurable linkage between the loci for Xg and for the X-linked forms of muscular dystrophy.

Blood Group Antigens↗
PubMed1986

Duchenne muscular dystrophy due to familial Xp21 deletion detectable by DNA analysis and flow cytometry.

We report two male cousins with Duchenne muscular dystrophy (DMD) in whom cytogenetic studies have shown a small interstitial deletion at Xp21. The lesion is readily detectable in patients and carriers by flow cytometry which indicates that approximately 6000 kb of DNA are deleted in each case. The DNA markers OTC, C7, and B24 are present in the deleted X chromosome but 87-8, 87-1, and 754 are absent. Despite apparently identical deletions one affected boy has profound mental handicap while the other is only mildly retarded. The results confirm the assignment of familial DMD to Xp21 and illustrate the value of flow cytometry in improving the precision of chromosome analysis. We have also undertaken flow cytometry in a cell line from a previously reported DMD patient with a de novo Xp21 deletion who had, in addition, chronic granulomatous disease, retinitis pigmentosa, and the McLeod syndrome. The results indicate that the amount of DNA deleted from the X is similar in both families despite the striking differences in phenotype.

Child↗
PubMed1994

Immunogold localization of the 43-kDa dystroglycan at the plasma membrane in control and dystrophic human muscle.

Immunofluorescence and immunogold labelling were used to localise the 43-kDa dystrophin-associated glycoprotein (43DAG) of the dystrophin-glycoprotein complex in control and Duchenne muscular dystrophy (DMD) biopsies. In control muscle 43DAG was localised by immunofluorescence to the periphery of the fibre and, by immunogold, was further delimited to the plasma membrane. The labelling was indistinguishable from that previously reported for the dystrophin C terminus. Moreover, the distance separating adjacent 43DAG labelling sites (120 nm mode) closely matched that separating dystrophin C-terminal sites. This is strong evidence supporting Ervasti & Campbell's model in which the DAG complex is bound close to the C terminus of dystrophin and in which the DAG complexes are separated by approximately the length of the dystrophin rod. In DMD, where there is a 80-90% reduction in the glycoprotein complex, a faint or locally patchy distribution of 43DAG was seen by immunofluorescence. Measurement of nearest-neighbour distances after immunogold labelling showed that in DMD the 43DAG was more dispersed, which is further evidence that dystrophin is normally involved in anchoring the DAGs in the plasma membrane. This is significant because the potential success of dystrophin gene therapy could depend not only on restoring dystrophin but also on restoring the lost DAGs.

Cell Membrane↗
PubMed1987

Atypical form of X-linked proximal pseudohypertrophic muscular dystrophy.

A series of 95 families, consisting of 317 patients with severe and mild X-linked proximal pseudohypertrophic muscular dystrophy (MD), was analysed by the use of two different and rigid clinical criteria based on the age when the patient became chairbound. Using these criteria the families from Erfurt and Warsaw could be clearly separated into classical Duchenne (DMD) and classical Becker (BMD) type patients. A third group of patients was found with atypical clinical course, who could not be identified as neither Duchenne nor Becker cases. Statistically highly significant differences were found between the groups of classical DMD and atypical MD cases on the one hand and between the groups of atypical MD and classical BMD cases on the other, especially with respect to age when chairbound and age at death. The comparisons of progression of the disease, life expectancy and of fertility between the three groups of X-linked MD show that classical DMD and atypical MD may be considered as separate types of severe X-linked proximal pseudohypertrophic MD. On the basis of these findings the authors offer conclusions for the general practice of neurology, paediatrics and genetic counseling.

Adolescent↗
PubMed1989

Duchenne muscular dystrophy carriers. Proton spin-lattice relaxation times of skeletal muscles on magnetic resonance imaging.

By means of magnetic resonance imaging (MRI), the proton spin-lattice relaxation times (T1 values) of the skeletal muscles were measured in Duchenne muscular dystrophy (DMD) carriers and normal controls. The bound water fraction (BWF) was calculated form the T1 values obtained, according to the fast proton diffusion model. In the DMD carriers, T1 values of the gluteus maximus and quadriceps femoris muscles were significantly higher, and BWFs of these muscles were significantly lower, than in normal control. Degenerative muscular changes accompanied by interstitial edema were presumed responsible for this abnormality. No correlation was observed between the muscle T1 and serum creatine kinase values. The present study showed that MRI could be a useful method for studying the dynamic state of water in both normal and pathological skeletal muscles. Its possible utility for DMD carrier detection was discussed briefly.

Adult↗
PubMed1993

In situ hybridization of myoglobin mRNA: results on the skeletal muscles of normal subjects and patients with neuromuscular diseases.

The intracellular localization of myoglobin(Mb) mRNA in the skeletal muscles of normal subjects and patients with Duchenne muscular dystrophy(DMD) or amyotrophic lateral sclerosis(ALS) was examined by in situ hybridization using a biotin-labeled cDNA probe. In cross sections of normal muscles, Mb mRNA signals were demonstrated to be diffusely distributed as granular reaction products throughout the sarcoplasm, and in longitudinal sections the products were observed preferentially on the A-band. In DMD or ALS muscles, the distribution of granular mRNA signals showed some similarities with that in normal muscles, although degenerated fibers revealed a heterogenous distribution of the signals. In DMD muscles, the optical density(OD) of stained signal was higher in non-atrophic fibers and lower in atrophic fibers than in normal muscles. In ALS muscles, the OD was lower than in normal muscles. These results suggest that Mb mRNA is distributed preferentially on the A-band of the muscle fibers, and that in diseased muscle fibers Mb synthesis is affected by pathological changes.

Adult↗