Duchenne muscular dystrophy caused by a frame-shift mutation in the acceptor splice site of intron 26

Background: The dystrophin gene is the one of the largest described in human beings and mutations associated to this gene are responsible for Duchenne or Becker muscular dystrophies. Case Presentation: Here we describe a nucleotide substitution in the acceptor splice site of intron 26 (c.3604-1G > C) carried by a 6-year-old boy who presented with a history of progressive proximal muscle weakness and elevated serum creatine kinase levels. RNA analysis showed that the first two nucleotides of the mutated intron 26 (AC) were not recognized by the splicing machinery and a new splicing site was created within exon 27, generating a premature stop codon and avoiding protein translation. Conclusions: The evaluation of the pathogenic effect of the mutation by mRNA analysis will be useful in the optics of an antisense oligonucleotides (AON)-based therapy

Inositol 1,4,5-trisphosphate (IP3)-dependent Ca2+ signaling mediates delayed myogenesis in Duchenne muscular dystrophy fetal muscle

Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disorder characterized by muscle wasting and premature death. The defective gene is dystrophin, a structural protein, absence of which causes membrane fragility and myofiber necrosis. Several lines of evidence showed that in adult DMD patients dystrophin is involved in signaling pathways that regulate calcium homeostasis and differentiation programs. However, secondary aspects of the disease, such as inflammation and fibrosis development, might represent a bias in the analysis. Because fetal muscle is not influenced by gravity and does not suffer from mechanical load and/or inflammation, we investigated 12-week-old fetal DMD skeletal muscles, highlighting for the first time early alterations in signaling pathways mediated by the absence of dystrophin itself. We found that PLC/IP3/IP3R/Ryr1/Ca2+ signaling is widely active in fetal DMD skeletal muscles and, through the calcium-dependent PKCa protein, exerts a fundamental regulatory role in delaying myogenesis and in myofiber commitment. These data provide new insights into the origin of DMD pathology during muscle development

Hmgb3 is regulated by microrna-206 during muscle regeneration.

MicroRNAs (miRNAs) have been recently involved in most of human diseases as targets for potential strategies to rescue the pathological phenotype. Since the skeletal muscle is a spread-wide highly differentiated and organized tissue, rescue of severely compromised muscle still remains distant from nowadays. For this reason, we aimed to identify a subset of miRNAs major involved in muscle remodelling and regeneration by analysing the miRNA-profile of single fibres isolated from dystrophic muscle, which was here considered as a model of chronic damage

Transcription, Epigenetics and Ameliorative Strategies in Huntington’s Disease: a Genome-Wide Perspective

ease (HD) is an early event that shapes the brain transcriptome by both the depletion and ectopic activation of gene products that eventually affect survival and neuronal functions. Disrup-tion in the activity of gene expression regulators, such as transcription factors, chromatin-remodeling proteins, and non-coding RNAs, accounts for the expression changes observed in multiple animal and cellular models of HD and in samples from patients. Here, I review the recent advances in the study of HD transcriptional dysregulation and its causes to finally discuss the possible implications in ameliorative strategies from a genome-wide perspective. To date, the use of genome-wide approaches, predominantly based on microar-ray platforms, has been successful in providing an extensive catalog of differentially regulated genes, including biomarkers aimed at monitoring the progress of the pathology. Although still incipient, the introduction of combined next-generation sequencing techniques is enhancing our comprehension of the mechanisms underlying altered transcriptional dysregulation in HD by providing the first genomic landscapes associated with epigenetics and the occupancy of transcription factors. In addition, the use of genome-wide approaches is becoming more and more necessary to evaluate the efficacy and safety of ameliorative strategies and to identify novel mechanisms of amelioration that may help in the improvement of current preclinical therapeutics. Finally, the major conclusions obtain-ed from HD transcriptomics studies have the potential to be extrapolated to other neurodegenerative disorders

Stem Cell Therapies to Treat Muscular Dystrophy : Progress to Date

Muscular dystrophies are heritable, heterogeneous neuromuscular disorders and include Duchenne and Becker muscular dystrophies (DMD and BMD, respectively). DMD patients exhibit progressive muscle weakness and atrophy followed by exhaustion of muscular regenerative capacity, fibrosis, and eventually disruption of the muscle tissue architecture. In-frame mutations in the dystrophin gene lead to expression of a partially functional protein, resulting in the milder BMD. No effective therapies are available at present. Cell-based therapies have been attempted in an effort to promote muscle regeneration, with the hope that the host cells would repopulate the muscle and improve muscle function and pathology. Injection of adult myoblasts has led to the development of new muscle fibers, but several limitations have been identified, such as poor cell survival and limited migratory ability. As an alternative to myoblasts, stem cells were considered preferable for therapeutic applications because of their capacity for self-renewal and differentiation potential. In recent years, encouraging results have been obtained with adult stem cells to treat human diseases such as leukemia, Parkinson's disease, stroke, and muscular dystrophies. Embryonic stem cells (ESCs) can be derived from mammalian embryos in the blastocyst stage, and because they can differentiate into a wide range of specialized cells, they hold potential for use in treating almost all human diseases. Several ongoing studies focus on this possibility, evaluating differentiation of specific cell lines from human ESCs (hESCs) as well as the potential tumorigenicity of hESCs. The most important limitation with using hESCs is that it requires destruction of human blastocysts or embryos. Conversely, adult stem cells have been identified in various tissues, where they serve to maintain, generate, and replace terminally differentiated cells within their specific tissue as the need arises for cell turnover or from tissue injury. Moreover, these cells can participate in regeneration of more than just their specific tissue type. Here we describe multiple types of muscle- and fetal-derived myogenic stem cells, their characterization, and their possible use in treating muscular dystrophies such as DMD and BMD. We also emphasize that the most promising possibility for the management and therapy of DMD and BMD is a combination of different approaches, such as gene and stem cell therapy

Predicted miRNAs in murine dystrophin gene

Duchenne muscular dystrophy (DMD) is a common X-linked disease characterized by frameshift mutations in the dystrophin gene. Among the molecular mechanisms potentially involved in DMD, we focused our attention on microRNAs (miRNAs) a new class of gene-expression regulators. The identification of new predicted miRNAs in dystrophin gene could evidence a molecular network specific for DMD. To predict the presence of pre-miRNA in the dystrophin gene, we analyzed its genomic sequence with three microRNA-gene prediction algorithms (mirEval, mirFinder and MiR-abela) which analyze criteria such as the secondary structure and free-folding energy of their precursors, conservation of part of the miRNA sequence or similarity with other miRNAs and since miRNA are occasionally found in clusters, analysis of genomic regions around already known miRNA. A set of 28 pre-miRNAs were predicted to be encoded within the dystrophin gene. The various predictions were compared considering the localization and the structure of the predicted stem loops; 14 of them were resulted in common to all three algorithms. Sequences of predicted miRNA were checked in miRbase and aligned with known stem-loop precursors and mature miRNAs. This analysis evidenced that five putative pre-miRNA showed significant similarity with known miRNAs thus letting suppose that the dystrophin gene could contain new transcription sites for annotated miRNAs. The remaining 23 predictions did not show any alignment with already validated miRNAs and could represent new miRNA molecules. Validation of these predicted miRNAs within dystrophin gene will add new intrinsic molecular networks to the characterization of DMD pathogenesis and could explain the variability of the DMD clinical phenotypes. However, all these findings raise the opportunity for therapeutic intervention at the miRNA level preventing specific pathways underlying this muscle disease. This work has been supported by the Associazione Amici del Centro Dino Ferrari, the Association Monégasque contre les Myopathies, Optistem 223098 and the Associazione La Nostra Famiglia Fondo DMD Gli Amici di Emanuele. MiRNA-dysregulation in dystrophic single fiber

Differential Activation of CD20-related Signaling Pathways Results in distinct differentiation behaviour of normal and DMD circulating CD133+ Stem Cells

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