Emerging strategies for cell and gene therapy of the muscular dystrophies

The muscular dystrophies are a heterogeneous group of over 40 disorders that are characterised by muscle weakness and wasting. The most common are Duchenne muscular dystrophy and Becker muscular dystrophy, which result from mutations within the gene encoding dystrophin; myotonic dystrophy type 1, which results from an expanded trinucleotide repeat in the myotonic dystrophy protein kinase gene; and facioscapulohumeral dystrophy, which is associated with contractions in the subtelomeric region of human chromosome 1. Currently the only treatments involve clinical management of symptoms, although several promising experimental strategies are emerging. These include gene therapy using adeno-associated viral, lentiviral and adenoviral vectors and nonviral vectors, such as plasmid DNA. Exon-skipping and cell-based therapies have also shown promise in the effective treatment and regeneration of dystrophic muscle. The availability of numerous animal models for Duchenne muscular dystrophy has enabled extensive testing of a wide range of therapeutic approaches for this type of disorder. Consequently, we focus here on the therapeutic developments for Duchenne muscular dystrophy as a model of the types of approaches being considered for various types of dystrophy. We discuss the advantages and limitations of each therapeutic strategy, as well as prospects and recent successes in the context of future clinical applications.

Download Full-text

Immunological hurdles in the path to gene therapy for Duchenne muscular dystrophy

Expert Reviews in Molecular Medicine ◽

10.1017/s146239940200515x ◽

2002 ◽

Vol 4 (23) ◽

pp. 1-23 ◽

Cited By ~ 22

Author(s):

Dominic J. Wells ◽

Aurora Ferrer ◽

Kim E. Wells

Keyword(s):

Gene Therapy ◽

Immune Response ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Gene Transfer ◽

Immune Responses ◽

Muscle Fibres ◽

Dystrophic Muscle ◽

Western Blots ◽

Muscle Wasting Disease

Patients with Duchenne muscular dystrophy (DMD), an X-linked lethal muscle-wasting disease, have abnormal expression of the protein dystrophin within their muscle fibres. In the mdx mouse model of this condition, both germline and neonatal somatic gene transfers of dystrophin cDNAs have demonstrated the potential of gene therapy in treating DMD. However, in many DMD patients, there appears to be no dystrophin expression when muscle biopsies are immunostained or western blots are performed. This raises the possibility that the expression of dystrophin following gene transfer might trigger a destructive immune response against this ‘neoantigen’. Immune responses can also be generated against the gene transfer vector used to transfect the dystrophic muscle, and the combined immune response could further damage the already inflamed muscle. These problems are now beginning to be investigated in immunocompetent mdx mice. Although much work remains to be done, there are promising indications that these immune responses might not prove as much of a concern as originally envisaged.

Download Full-text

Dlk1-Dio3 cluster miRNAs regulate mitochondrial functions in Duchenne muscular dystrophy

10.1101/2021.10.20.464950 ◽

2021 ◽

Author(s):

Ai VU Hong ◽

Nathalie Bourg ◽

Peggy Sanatine ◽

Jerome Poupiot ◽

Karine Charton ◽

...

Keyword(s):

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Mitochondrial Dysfunction ◽

Muscular Dystrophies ◽

Mirna Cluster ◽

Biological Functions ◽

Dystrophic Muscle ◽

Mitochondrial Functions ◽

Mirnas Expression

Background: Duchenne Muscular Dystrophy (DMD) is a severe muscle disease caused by impaired expression of dystrophin. While mitochondrial dysfunction is thought to play an important role in DMD, the mechanism of this dysfunction remains to be clarified. We recently identified in DMD and in other muscular dystrophies the upregulation of a large number of the Dlk1-Dio3 clustered miRNAs (DD-miRNAs), in both the muscle and the serum. The objective of the present study was to define the biological functions of DD-miRNAs in skeletal muscle, particularly in the context of muscular dystrophy. Methods: DD-miRNAs expression pattern was characterized in vitro and in vivo, in normal and dystrophic situations. Epigenomic characterization was performed, to elucidate the molecular control of DD-miRNAs dysregulation. The biological effect of muscle DD-miRNAs dysregulation was investigated by an in vivo simultaneous overexpression of 14 DD-miRNAs in the wild-type muscle, together with CRISPR-Cas9-based knockdown of the entire DD-miRNA cluster in an iPS-derived myotubes. Omics data and bioinformatics tools were used for the prediction of DD-miRNAs biological functions, and functional characterization of mitochondrial pathways was performed. Results: We found that DD-miRNAs dysregulation is not specific to DMD since observed in mouse models for other muscular dystrophies. We showed that DD-miRNAs expression in mdx, is reduced in satellite cells, but highly upregulated in regenerating myofibers, suggesting a myofibers origin of DD6miRNA upregulation in muscular dystrophy in both muscles and serum. We demonstrated that upregulation of DD-miRNAs in the dystrophic muscle is controlled epigenetically by DNA and histone methylation (p<0.0001 and p=0.001, respectively) at the Intergenic Differentially Methylated Region (IG-DMR) of Dlk1-Dio3 locus. Transcriptomic analysis revealed a substantial overlap between the dystrophic muscle of the mdx mouse and the normal muscle that overexpressed 14 DD-miRNAs. Bioinformatics analysis predicted that DD-miRNAs could regulate mitochondrial functions. The ectopic overexpression of 14 DD-miRNAs, in the healthy muscle, resulted in a drastic downregulation of mitochondrial oxidative phosphorylation (OxPhos) (NES=-2.8, p=8.7E-17), similarly to the level in dystrophic muscles of mdx mice and DMD patients (NES=-2.88, p=7.7E-28). Knocking down the entire DD-miRNA cluster in iPS-derived myotubes resulted in increased mitochondrial OxPhos expression and activities. Conclusions: The present study provides evidence for the modulation of mitochondrial activity in the dystrophic muscle by the upregulated DD-miRNAs and supports an updated model for mitochondrial dysfunction in DMD. The regulation of mitochondrial OxPhos by DD-miRNAs may have a broader impact beyond DMD in physiological and pathological situations of muscle adaptation and regeneration.

Download Full-text

Advances in gene therapy for muscular dystrophies

F1000Research ◽

10.12688/f1000research.8735.1 ◽

2016 ◽

Vol 5 ◽

pp. 2030 ◽

Cited By ~ 10

Author(s):

Hayder Abdul-Razak ◽

Alberto Malerba ◽

George Dickson

Keyword(s):

Gene Therapy ◽

Duchenne Muscular Dystrophy ◽

Muscular Dystrophy ◽

Gene Transcription ◽

Therapeutic Strategies ◽

Mrna Processing ◽

Muscular Dystrophies ◽

Gene Encoding ◽

Recessive Lethal ◽

Cellular Machinery

Duchenne muscular dystrophy (DMD) is a recessive lethal inherited muscular dystrophy caused by mutations in the gene encoding dystrophin, a protein required for muscle fibre integrity. So far, many approaches have been tested from the traditional gene addition to newer advanced approaches based on manipulation of the cellular machinery either at the gene transcription, mRNA processing or translation levels. Unfortunately, despite all these efforts, no efficient treatments for DMD are currently available. In this review, we highlight the most advanced therapeutic strategies under investigation as potential DMD treatments.

Download Full-text