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Life Science Alliance Oct 2021Absence of dystrophin, an essential sarcolemmal protein required for muscle contraction, leads to the devastating muscle-wasting disease Duchenne muscular dystrophy....
Absence of dystrophin, an essential sarcolemmal protein required for muscle contraction, leads to the devastating muscle-wasting disease Duchenne muscular dystrophy. Dystrophin has an actin-binding domain, which binds and stabilises filamentous-(F)-actin, an integral component of the RhoA-actin-serum-response-factor-(SRF) pathway. This pathway plays a crucial role in circadian signalling, whereby the suprachiasmatic nucleus (SCN) transmits cues to peripheral tissues, activating SRF and transcription of clock-target genes. Given dystrophin binds F-actin and disturbed SRF-signalling disrupts clock entrainment, we hypothesised dystrophin loss causes circadian deficits. We show for the first time alterations in the RhoA-actin-SRF-signalling pathway, in dystrophin-deficient myotubes and dystrophic mouse models. Specifically, we demonstrate reduced F/G-actin ratios, altered MRTF levels, dysregulated core-clock and downstream target-genes, and down-regulation of key circadian genes in muscle biopsies from Duchenne patients harbouring an array of mutations. Furthermore, we show dystrophin is absent in the SCN of dystrophic mice which display disrupted circadian locomotor behaviour, indicative of disrupted SCN signalling. Therefore, dystrophin is an important component of the RhoA-actin-SRF pathway and novel mediator of circadian signalling in peripheral tissues, loss of which leads to circadian dysregulation.
Topics: Actins; Animals; Cell Line; Dystrophin; Mice; Myoblasts, Skeletal; Serum Response Factor; Signal Transduction; Utrophin; rhoA GTP-Binding Protein
PubMed: 34389686
DOI: 10.26508/lsa.202101014 -
Cellular Oncology (Dordrecht) Feb 2021Mutation of the Duchenne muscular dystrophy (DMD) gene causes Duchenne and Becker muscular dystrophy, degenerative neuromuscular disorders that primarily affect... (Review)
Review
BACKGROUND
Mutation of the Duchenne muscular dystrophy (DMD) gene causes Duchenne and Becker muscular dystrophy, degenerative neuromuscular disorders that primarily affect voluntary muscles. However, increasing evidence implicates DMD in the development of all major cancer types. DMD is a large gene with 79 exons that codes for the essential muscle protein dystrophin. Alternative promotor usage drives the production of several additional dystrophin protein products with roles that extend beyond skeletal muscle. The importance and function(s) of these gene products outside of muscle are not well understood.
CONCLUSIONS
We highlight a clear role for DMD in the pathogenesis of several cancers, including sarcomas, leukaemia's, lymphomas, nervous system tumours, melanomas and various carcinomas. We note that the normal balance of DMD gene products is often disrupted in cancer. The short dystrophin protein Dp71 is, for example, typically maintained in cancer whilst the full-length Dp427 gene product, a likely tumour suppressor, is frequently inactivated in cancer due to a recurrent loss of 5' exons. Therefore, the ratio of short and long gene products may be important in tumorigenesis. In this review, we summarise the tumours in which DMD is implicated and provide a hypothesis for possible mechanisms of tumorigenesis, although the question of cause or effect may remain. We hope to stimulate further study into the potential role of DMD gene products in cancer and the development of novel therapeutics that target DMD.
Topics: Animals; Dystrophin; Genetic Predisposition to Disease; Humans; Models, Biological; Muscular Dystrophy, Duchenne; Neoplasms
PubMed: 33188621
DOI: 10.1007/s13402-020-00572-y -
Bosnian Journal of Basic Medical... Jul 2015Mutations of the dystrophin DMD gene, essentially deletions of one or several exons, are the cause of two devastating and to date incurable diseases, Duchenne (DMD) and... (Review)
Review
Mutations of the dystrophin DMD gene, essentially deletions of one or several exons, are the cause of two devastating and to date incurable diseases, Duchenne (DMD) and Becker (BMD) muscular dystrophies. Depending upon the preservation or not of the reading frame, dystrophin is completely absent in DMD, or present in either a mutated or a truncated form in BMD. DMD is a severe disease which leads to a premature death of the patients. Therapy approaches are evolving with the aim to transform the severe DMD in the BMD form of the disease by restoring the expression of a mutated or truncated dystrophin. These therapies are based on the assumption that BMD is a mild disease. However, this is not completely true as BMD patients are more or less severely affected and no molecular basis of this heterogeneity of the BMD form of the disease is yet understood. The aim of this review is to report for the correlation between dystrophin structures in BMD deletions in view of this heterogeneity and to emphasize that examining BMD patients in details is highly relevant to anticipate for DMD therapy effects.
Topics: Dystrophin; Humans; Muscular Dystrophy, Duchenne; Mutation
PubMed: 26295289
DOI: 10.17305/bjbms.2015.636 -
Neuroscience Letters Mar 2020The Dystrophin Glycoprotein Complex (DGC) is a large multi-protein complex that links cytoskeleton actin to the extracellular matrix. This complex is critical in... (Review)
Review
The Dystrophin Glycoprotein Complex (DGC) is a large multi-protein complex that links cytoskeleton actin to the extracellular matrix. This complex is critical in maintaining the structural integrity of muscle fibers and the stability of the neuromuscular synapse. The DGC consists of dystrophin and its utrophin homolog, as well as dystroglycans, sarcoglycans, sarcospan, syntrophins, and dystrobrevins. Deficiencies in DGC proteins result in several forms of muscular dystrophy with varying symptoms and degrees of severity in addition to structurally abnormal neuromuscular junctions (NMJs). This mini-review highlights current knowledge regarding the role of the DGC on the molecular dynamics of acetylcholine receptors (AChRs) as it relates to the formation and maintenance of the mammalian NMJ.
Topics: Animals; Dystrophin; Glycoproteins; Humans; Neuromuscular Junction; Receptors, Cholinergic
PubMed: 32057921
DOI: 10.1016/j.neulet.2020.134833 -
Circulation Research Sep 2017Gene editing is moving rapidly from a highly useful laboratory-based tool towards human clinical application. gene editing has been documented in mouse models of...
Gene editing is moving rapidly from a highly useful laboratory-based tool towards human clinical application. gene editing has been documented in mouse models of Duchenne Muscular Dystrophy, where skeletal and cardiac muscle editing produces internally-truncated dystrophin. A recent report now demonstrates that editing the dystrophin gene in the heart improves cardiac function, paving the path to application of cardiac gene correction.
Topics: Animals; CRISPR-Cas Systems; Clustered Regularly Interspaced Short Palindromic Repeats; Dystrophin; Gene Editing; Mice; Mutation
PubMed: 28963182
DOI: 10.1161/CIRCRESAHA.117.311865 -
Methods in Molecular Biology (Clifton,... 2023Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disorder, caused by mutations in the DMD gene coding dystrophin. Applying clustered regularly interspaced...
Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disorder, caused by mutations in the DMD gene coding dystrophin. Applying clustered regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated proteins (CRISPR-Cas) for therapeutic gene editing represents a promising technology to correct this devastating disease through elimination of underlying genetic mutations. Adeno-associated virus (AAV) has been widely used for gene therapy due to its low immunogenicity and high tissue tropism. In particular, CRISPR-Cas9 gene editing components packaged by self-complementary AAV (scAAV) demonstrate robust viral transduction and efficient gene editing, enabling restoration of dystrophin expression throughout skeletal and cardiac muscle in animal models of DMD. Here, we describe protocols for cloning CRISPR single guide RNAs (sgRNAs) into a scAAV plasmid and procedures for systemic delivery of AAVs into a DMD mouse model. We also provide methodologies for quantification of dystrophin restoration after systemic CRISPR-Cas9-mediated correction of DMD.
Topics: Mice; Animals; Dystrophin; Muscular Dystrophy, Duchenne; Dependovirus; CRISPR-Cas Systems; Exons; Muscle, Skeletal
PubMed: 36401041
DOI: 10.1007/978-1-0716-2772-3_21 -
International Journal of Molecular... Oct 2021Duchenne muscular dystrophy (DMD) leads to disability and death in young men. This disease is caused by mutations in the gene encoding diverse isoforms of dystrophin.... (Review)
Review
Duchenne muscular dystrophy (DMD) leads to disability and death in young men. This disease is caused by mutations in the gene encoding diverse isoforms of dystrophin. Loss of full-length dystrophins is both necessary and sufficient for causing degeneration and wasting of striated muscles, neuropsychological impairment, and bone deformities. Among this spectrum of defects, abnormalities of calcium homeostasis are the common dystrophic feature. Given the fundamental role of Ca in all cells, this biochemical alteration might be underlying all the DMD abnormalities. However, its mechanism is not completely understood. While abnormally elevated resting cytosolic Ca concentration is found in all dystrophic cells, the aberrant mechanisms leading to that outcome have cell-specific components. We probe the diverse aspects of calcium response in various affected tissues. In skeletal muscles, cardiomyocytes, and neurons, dystrophin appears to serve as a scaffold for proteins engaged in calcium homeostasis, while its interactions with actin cytoskeleton influence endoplasmic reticulum organisation and motility. However, in myoblasts, lymphocytes, endotheliocytes, and mesenchymal and myogenic cells, calcium abnormalities cannot be clearly attributed to the loss of interaction between dystrophin and the calcium toolbox proteins. Nevertheless, DMD gene mutations in these cells lead to significant defects and the calcium anomalies are a symptom of the early developmental phase of this pathology. As the impaired calcium homeostasis appears to underpin multiple DMD abnormalities, understanding this alteration may lead to the development of new therapies. In fact, it appears possible to mitigate the impact of the abnormal calcium homeostasis and the dystrophic phenotype in the total absence of dystrophin. This opens new treatment avenues for this incurable disease.
Topics: Calcium; Calcium Signaling; Dystrophin; Endoplasmic Reticulum; Humans; Mitochondria; Muscle, Skeletal; Muscular Dystrophy, Duchenne
PubMed: 34681707
DOI: 10.3390/ijms222011040 -
Orphanet Journal of Rare Diseases Aug 2022Duchenne muscular dystrophy (DMD) is a clinically common X-linked recessive myopathy, which is caused by mutation of the gene encoding dystrophin on chromosome Xp21. The... (Review)
Review
Duchenne muscular dystrophy (DMD) is a clinically common X-linked recessive myopathy, which is caused by mutation of the gene encoding dystrophin on chromosome Xp21. The onset of heart injury in children with DMD is inconspicuous, and the prognosis is poor once it develops to the stage of heart failure. Cardiovascular complications remain an important cause of death in this patient population. At present, population and animal studies have suggested that Electrocardiogram (ECG) changes may be the initial manifestation of cardiac involvement in children with DMD. Relevant clinical studies have also confirmed that significant abnormal ECG changes already exist in DMD patients before cardiomegaly and/or LVEF decrease. With increases in age and decreases in cardiac function, the proportion of ECG abnormalities in DMD patients increase significantly. Some characteristic ECG changes, such as ST-segment changes, T wave inversion, Q wave at the inferolateral leads, LBBB and SDANN, have a certain correlation with the indexes of cardiac remodeling or impaired cardiac function in DMD patients, while VT and LBBB have demonstrated relatively good predictive value for the occurrence of long-term DCM and/or adverse cardiovascular events or even death in DMD patients. The present review discusses the electrocardiographic features in children with DMD.
Topics: Animals; Dystrophin; Electrocardiography; Heart; Heart Diseases; Humans; Muscular Dystrophy, Duchenne
PubMed: 35987773
DOI: 10.1186/s13023-022-02473-9 -
Gene Therapy Nov 2022Duchenne muscular dystrophy (DMD) is a lethal, degenerative muscle disorder caused by mutations in the DMD gene, leading to severe reduction or absence of the protein...
Duchenne muscular dystrophy (DMD) is a lethal, degenerative muscle disorder caused by mutations in the DMD gene, leading to severe reduction or absence of the protein dystrophin. Gene therapy strategies that aim to increase expression of a functional dystrophin protein (mini-dystrophin) are under investigation. The ability to accurately quantify dystrophin/mini-dystrophin is essential in assessing the level of gene transduction. We demonstrated the validation and application of a novel peptide immunoaffinity liquid chromatography-tandem mass spectrometry (IA-LC-MS/MS) assay. Data showed that dystrophin expression in Becker muscular dystrophy and DMD tissues, normalized against the mean of non-dystrophic control tissues (n = 20), was 4-84.5% (mean 32%, n = 20) and 0.4-24.1% (mean 5%, n = 20), respectively. In a DMD rat model, biceps femoris tissue from dystrophin-deficient rats treated with AAV9.hCK.Hopti-Dys3978.spA, an adeno-associated virus vector containing a mini-dystrophin transgene, showed a dose-dependent increase in mini-dystrophin expression at 6 months post-dose, exceeding wildtype dystrophin levels at high doses. Validation data showed that inter- and intra-assay precision were ≤20% (≤25% at the lower limit of quantification [LLOQ]) and inter- and intra-run relative error was within ±20% (±25% at LLOQ). IA-LC-MS/MS accurately quantifies dystrophin/mini-dystrophin in human and preclinical species with sufficient sensitivity for immediate application in preclinical/clinical trials.
Topics: Humans; Rats; Animals; Dystrophin; Muscular Dystrophy, Duchenne; Chromatography, Liquid; Tandem Mass Spectrometry; Muscle, Skeletal; Genetic Therapy
PubMed: 34737451
DOI: 10.1038/s41434-021-00300-7 -
PloS One 2023Duchenne muscular dystrophy (DMD) is caused by genetic mutations leading to lack of dystrophin in skeletal muscle. A better understanding of how objective biomarkers for...
Duchenne muscular dystrophy (DMD) is caused by genetic mutations leading to lack of dystrophin in skeletal muscle. A better understanding of how objective biomarkers for DMD vary across subjects and over time is needed to model disease progression and response to therapy more effectively, both in pre-clinical and clinical research. We present an in-depth characterization of disease progression in 3 murine models of DMD by multiomic analysis of longitudinal trajectories between 6 and 30 weeks of age. Integration of RNA-seq, mass spectrometry-based metabolomic and lipidomic data obtained in muscle and blood samples by Multi-Omics Factor Analysis (MOFA) led to the identification of 8 latent factors that explained 78.8% of the variance in the multiomic dataset. Latent factors could discriminate dystrophic and healthy mice, as well as different time-points. MOFA enabled to connect the gene expression signature in dystrophic muscles, characterized by pro-fibrotic and energy metabolism alterations, to inflammation and lipid signatures in blood. Our results show that omic observations in blood can be directly related to skeletal muscle pathology in dystrophic muscle.
Topics: Mice; Animals; Dystrophin; Mice, Inbred mdx; Multiomics; Muscular Dystrophy, Duchenne; Muscle, Skeletal; Disease Progression; Disease Models, Animal
PubMed: 37000843
DOI: 10.1371/journal.pone.0283869