Developing DMD therapeutics: a review of the effectiveness of small molecules, stop-codon readthrough, dystrophin gene replacement, and exon-skipping therapies

Author(s):  
Omar Sheikh ◽  
Toshifumi Yokota
2015 ◽  
Vol 15 (6) ◽  
pp. 563-571 ◽  
Author(s):  
Mirella Meregalli ◽  
Andrea Farini ◽  
Clementina Sitzia ◽  
Cyriaque Beley ◽  
Paola Razini ◽  
...  

2012 ◽  
Vol 287 (21) ◽  
pp. 17765-17776 ◽  
Author(s):  
Yoshihide Yamaguchi ◽  
Akiko Hayashi ◽  
Celia W. Campagnoni ◽  
Akio Kimura ◽  
Takashi Inuzuka ◽  
...  

Author(s):  
Vratko Himič ◽  
Kay E. Davies

AbstractDuchenne muscular dystrophy (DMD) is an X-linked progressive muscle-wasting disorder that is caused by a lack of functional dystrophin, a cytoplasmic protein necessary for the structural integrity of muscle. As variants in the dystrophin gene lead to a disruption of the reading frame, pharmacological treatments have only limited efficacy; there is currently no effective therapy and consequently, a significant unmet clinical need for DMD. Recently, novel genetic approaches have shown real promise in treating DMD, with advancements in the efficacy and tropism of exon skipping and surrogate gene therapy. CRISPR-Cas9 has the potential to be a ‘one-hit’ curative treatment in the coming decade. The current limitations of gene editing, such as off-target effects and immunogenicity, are in fact partly constraints of the delivery method itself, and thus research focus has shifted to improving the viral vector. In order to halt the loss of ambulation, early diagnosis and treatment will be pivotal. In an era where genetic sequencing is increasingly utilised in the clinic, genetic therapies will play a progressively central role in DMD therapy. This review delineates the relative merits of cutting-edge genetic approaches, as well as the challenges that still need to be overcome before they become clinically viable.


Viruses ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1230
Author(s):  
Sawsan Napthine ◽  
Chris H. Hill ◽  
Holly C. M. Nugent ◽  
Ian Brierley

The product of the interferon-stimulated gene C19orf66, Shiftless (SHFL), restricts human immunodeficiency virus replication through downregulation of the efficiency of the viral gag/pol frameshifting signal. In this study, we demonstrate that bacterially expressed, purified SHFL can decrease the efficiency of programmed ribosomal frameshifting in vitro at a variety of sites, including the RNA pseudoknot-dependent signals of the coronaviruses IBV, SARS-CoV and SARS-CoV-2, and the protein-dependent stimulators of the cardioviruses EMCV and TMEV. SHFL also reduced the efficiency of stop-codon readthrough at the murine leukemia virus gag/pol signal. Using size-exclusion chromatography, we confirm the binding of the purified protein to mammalian ribosomes in vitro. Finally, through electrophoretic mobility shift assays and mutational analysis, we show that expressed SHFL has strong RNA binding activity that is necessary for full activity in the inhibition of frameshifting, but shows no clear specificity for stimulatory RNA structures.


Genetics ◽  
1996 ◽  
Vol 143 (1) ◽  
pp. 345-351
Author(s):  
Carol J Williams ◽  
Kevin O'Hare

Abstract The suppressor of forked [su(f)] locus affects the phenotype of mutations caused by transposable element insertions at unlinked loci. It encodes a putative 84-kD protein with homology to two proteins involved in mRNA 3′ end processing; the product of the yeast RNA14 gene and the 77-kD subunit of human cleavage stimulation factor. Three su(f) mRNAs are produced by alternative polyadenylation. The 2. 6 and 2.9-kb mRNAs encode the same 84-kD protein while a 1.3-kb RNA, which terminates within the fourth intron, is unusual in having no stop codon. Using P-element-mediated gene replacement we have copied sequences from a transformation construct into the su(f) gene creating a su(f) allele at the normal genomic location that lacks the first five introns. This allele is viable and appears wild type for su(f) function, demonstrating that the 1.3-kb RNA and the sequences contained within the deleted introns are dispensable for su(f) function. Compared with studies on gene replacement at the white locus, chromosomal breaks at su(f) appear to be less efficiently repaired from ectopic sites, perhaps because of the location of su(f) at the euchromatin/heterochromatin boundary on the X chromosome.


Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 648
Author(s):  
Andrea L. Reid ◽  
Matthew S. Alexander

Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease caused by a pathogenic disruption of the DYSTROPHIN gene that results in non-functional dystrophin protein. DMD patients experience loss of ambulation, cardiac arrhythmia, metabolic syndrome, and respiratory failure. At the molecular level, the lack of dystrophin in the muscle results in myofiber death, fibrotic infiltration, and mitochondrial dysfunction. There is no cure for DMD, although dystrophin-replacement gene therapies and exon-skipping approaches are being pursued in clinical trials. Mitochondrial dysfunction is one of the first cellular changes seen in DMD myofibers, occurring prior to muscle disease onset and progresses with disease severity. This is seen by reduced mitochondrial function, abnormal mitochondrial morphology and impaired mitophagy (degradation of damaged mitochondria). Dysfunctional mitochondria release high levels of reactive oxygen species (ROS), which can activate pro-inflammatory pathways such as IL-1β and IL-6. Impaired mitophagy in DMD results in increased inflammation and further aggravates disease pathology, evidenced by increased muscle damage and increased fibrosis. This review will focus on the critical interplay between mitophagy and inflammation in Duchenne muscular dystrophy as a pathological mechanism, as well as describe both candidate and established therapeutic targets that regulate these pathways.


Open Biology ◽  
2016 ◽  
Vol 6 (11) ◽  
pp. 160246 ◽  
Author(s):  
Julia Hofhuis ◽  
Fabian Schueren ◽  
Christopher Nötzel ◽  
Thomas Lingner ◽  
Jutta Gärtner ◽  
...  

Translational readthrough gives rise to C-terminally extended proteins, thereby providing the cell with new protein isoforms. These may have different properties from the parental proteins if the extensions contain functional domains. While for most genes amino acid incorporation at the stop codon is far lower than 0.1%, about 4% of malate dehydrogenase (MDH1) is physiologically extended by translational readthrough and the actual ratio of MDH1x (e x tended protein) to ‘normal' MDH1 is dependent on the cell type. In human cells, arginine and tryptophan are co-encoded by the MDH1x UGA stop codon. Readthrough is controlled by the 7-nucleotide high-readthrough stop codon context without contribution of the subsequent 50 nucleotides encoding the extension. All vertebrate MDH1x is directed to peroxisomes via a hidden peroxisomal targeting signal (PTS) in the readthrough extension, which is more highly conserved than the extension of lactate dehydrogenase B. The hidden PTS of non-mammalian MDH1x evolved to be more efficient than the PTS of mammalian MDH1x. These results provide insight into the genetic and functional co-evolution of these dually localized dehydrogenases.


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