scholarly journals Single-cut genome editing restores dystrophin expression in a new mouse model of muscular dystrophy

2017 ◽  
Vol 9 (418) ◽  
pp. eaan8081 ◽  
Author(s):  
Leonela Amoasii ◽  
Chengzu Long ◽  
Hui Li ◽  
Alex A. Mireault ◽  
John M. Shelton ◽  
...  
Keyword(s):  
Muscular Dystrophy ◽  
Mouse Model ◽  
Genome Editing ◽  
Neuromuscular Disorders ◽  
Dystrophin Gene ◽  
Muscle Disease ◽  
Systemic Delivery ◽  
Specific Expression ◽  
Reading Frame ◽  
Dystrophin Protein

Duchenne muscular dystrophy (DMD) is a severe, progressive muscle disease caused by mutations in the dystrophin gene. The majority of DMD mutations are deletions that prematurely terminate the dystrophin protein. Deletions of exon 50 of the dystrophin gene are among the most common single exon deletions causing DMD. Such mutations can be corrected by skipping exon 51, thereby restoring the dystrophin reading frame. Using clustered regularly interspaced short palindromic repeats/CRISPR-associated 9 (CRISPR/Cas9), we generated a DMD mouse model by deleting exon 50. These ΔEx50 mice displayed severe muscle dysfunction, which was corrected by systemic delivery of adeno-associated virus encoding CRISPR/Cas9 genome editing components. We optimized the method for dystrophin reading frame correction using a single guide RNA that created reframing mutations and allowed skipping of exon 51. In conjunction with muscle-specific expression of Cas9, this approach restored up to 90% of dystrophin protein expression throughout skeletal muscles and the heart of ΔEx50 mice. This method of permanently bypassing DMD mutations using a single cut in genomic DNA represents a step toward clinical correction of DMD mutations and potentially those of other neuromuscular disorders.

scholarly journals The Interplay of Mitophagy and Inflammation in Duchenne Muscular Dystrophy

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 648
Author(s):  
Andrea L. Reid ◽  
Matthew S. Alexander
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mitochondrial Dysfunction ◽  
Disease Onset ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Muscle Disease ◽  
Mitochondrial Morphology ◽  
Gene Therapies ◽  
Dystrophin Protein

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.

scholarly journals Duchenne Muscular Dystrophy - Family in a Crisis

1970 ◽  
pp. 36-39
Author(s):  
M Robed Amin ◽  
Chowdhury Chironjib Borua ◽  
Kaji Shafiqul Alam ◽  
Fazle Rabbi Chowdhury ◽  
Rabiul Jahan Sarkar ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Case Series ◽  
Dystrophin Gene ◽  
Muscle Disease ◽  
Motor Neuron Diseases ◽  
Muscle Diseases ◽  
Progressive Muscle Weakness ◽  
Recessive Disorders ◽  
Dystrophin Protein

Progressive muscular weakness with deformity leading to crippled states develop due to musculoskeletal and neurological disorders. Sometimes it is difficult to differentiate between primary muscle disease and neurological disease. But there is some classical presentation of muscle diseases which have its own entity and thus can be clinically differentiated from neurological disorder especially spinal cord and motor neuron diseases. Muscular dystrophy is one of those disorder with distinct clinical features. Muscular dystrophy refers to a group of genetic, hereditary muscle diseases that cause progressive muscle weakness. Most types of MD are multi-system disorders with manifestations in body systems including skeletal system, the heart, gastrointestinal and nervous systems, endocrine glands, skin, eyes and other organs. Duchenne muscular dystrophy (DMD), is inherited in an X-linked recessive pattern, meaning that the mutated gene that causes the disorder is located on the X chromosome, one of the two sex chromosomes, and is thus considered sex-linked. Males are therefore affected by X-linked recessive disorders much more often than females. A characteristic of X-linked inheritance is that fathers cannot pass X-linked traits to their sons. Duchenne muscular dystrophy and Backers muscular dystrophy are caused by mutations of the gene for the dystrophin protein and lead to an overabundance of the enzyme creatine kinase. The dystrophin gene is the largest gene in humans. In this case series a family with three brothers suffering from Duchenne muscular dystrophy is described and review with literature was done.   doi:10.3329/jom.v10i3.2015 J Medicine 2009; 10 (Supplement 1): 36-39

scholarly journals Therapeutic Strategies for Duchenne Muscular Dystrophy: An Update

Genes ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 837 ◽  
Author(s):  
Chengmei Sun ◽  
Luoan Shen ◽  
Zheng Zhang ◽  
Xin Xie
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Motor Neurons ◽  
Neuromuscular Junctions ◽  
Neuromuscular Disorders ◽  
Dystrophin Gene ◽  
Current Status ◽  
Muscle Stem Cells ◽  
Cell Based Therapy ◽  
Dystrophin Protein

Neuromuscular disorders encompass a heterogeneous group of conditions that impair the function of muscles, motor neurons, peripheral nerves, and neuromuscular junctions. Being the most common and most severe type of muscular dystrophy, Duchenne muscular dystrophy (DMD), is caused by mutations in the X-linked dystrophin gene. Loss of dystrophin protein leads to recurrent myofiber damage, chronic inflammation, progressive fibrosis, and dysfunction of muscle stem cells. Over the last few years, there has been considerable development of diagnosis and therapeutics for DMD, but current treatments do not cure the disease. Here, we review the current status of DMD pathogenesis and therapy, focusing on mutational spectrum, diagnosis tools, clinical trials, and therapeutic approaches including dystrophin restoration, gene therapy, and myogenic cell transplantation. Furthermore, we present the clinical potential of advanced strategies combining gene editing, cell-based therapy with tissue engineering for the treatment of muscular dystrophy.

scholarly journals Precise correction of Duchenne muscular dystrophy exon deletion mutations by base and prime editing

2021 ◽  
Vol 7 (18) ◽  
pp. eabg4910
Author(s):  
F. Chemello ◽  
A. C. Chai ◽  
H. Li ◽  
C. Rodriguez-Caycedo ◽  
E. Sanchez-Ortiz ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Membrane Integrity ◽  
Dystrophin Gene ◽  
Muscle Disease ◽  
Muscle Membrane ◽  
Reading Frame ◽  
Split Intein ◽  
Virus Serotype

Duchenne muscular dystrophy (DMD) is a fatal muscle disease caused by the lack of dystrophin, which maintains muscle membrane integrity. We used an adenine base editor (ABE) to modify splice donor sites of the dystrophin gene, causing skipping of a common DMD deletion mutation of exon 51 (∆Ex51) in cardiomyocytes derived from human induced pluripotent stem cells, restoring dystrophin expression. Prime editing was also capable of reframing the dystrophin open reading frame in these cardiomyocytes. Intramuscular injection of ∆Ex51 mice with adeno-associated virus serotype-9 encoding ABE components as a split-intein trans-splicing system allowed gene editing and disease correction in vivo. Our findings demonstrate the effectiveness of nucleotide editing for the correction of diverse DMD mutations with minimal modification of the genome, although improved delivery methods will be required before these strategies can be used to sufficiently edit the genome in patients with DMD.

scholarly journals Genome editing for Duchenne muscular dystrophy: a glimpse of the future?

Gene Therapy ◽  
2021 ◽  
Author(s):  
Christian Kupatt ◽  
Alina Windisch ◽  
Alessandra Moretti ◽  
Eckhard Wolf ◽  
Wolfgang Wurst ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Genome Editing ◽  
Rare Event ◽  
Severe Form ◽  
Muscle Disease ◽  
End Joining ◽  
Reading Frame ◽  
Non Homologous End Joining ◽  
Large Animals

AbstractMutations in Dystrophin, one of the largest proteins in the mammalian body, are causative for a severe form of muscle disease, Duchenne Muscular Dystrophy (DMD), affecting not only skeletal muscle, but also the heart. In particular, exons 45–52 constitute a hotspot for DMD mutations. A variety of molecular therapies have been developed, comprising vectors encoding micro- and minidystrophins as well as utrophin, a protein with partially overlapping functions. With the advent of the CRISPR-Cas9-nuclease, genome editing offers a novel option of correction of the disease-cuasing mutations. Full restoration of the healthy gene by homology directed repair is a rare event. However, non-homologous end-joining (NHEJ) may restore the reading frame by causing exon excision. This approach has first been demonstrated in mice and then translated to large animals (dogs, pigs). This review discusses the potential opportunities and limitations of genome editing in DMD, including the generation of appropriate animal models as well as new developments in genome editing tools.

scholarly journals Intramuscular Evaluation of Chimeric Locked Nucleic Acid/2’OMethyl-Modified Antisense Oligonucleotides for Targeted Exon 23 Skipping in Mdx Mice

2021 ◽  
Vol 14 (11) ◽  
pp. 1113
Author(s):  
Michaella Georgiadou ◽  
Melina Christou ◽  
Kleitos Sokratous Sokratous ◽  
Jesper Wengel ◽  
Kyriaki Michailidou ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Therapeutic Potential ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Locked Nucleic Acid ◽  
Mdx Mice ◽  
Muscle Fibres ◽  
Systemic Delivery ◽  
Reading Frame ◽  
Dystrophin Protein

Duchenne muscular dystrophy (DMD) is a fatal disorder characterised by progressive muscle wasting. It is caused by mutations in the dystrophin gene, which disrupt the open reading frame leading to the loss of functional dystrophin protein in muscle fibres. Antisense oligonucleotide (AON)-mediated skipping of the mutated exon, which allows production of a truncated but partially functional dystrophin protein, has been at the forefront of DMD therapeutic research for over two decades. Nonetheless, novel nucleic acid modifications and AON designs are continuously being developed to improve the clinical benefit profile of current drugs in the DMD pipeline. We herein designed a series of 15mer and 20mer AONs, consisting of 2’O-Methyl (2’OMe)- and locked nucleic acid (LNA)-modified nucleotides in different percentage compositions, and assessed their efficiency in inducing exon 23 skipping and dystrophin restoration in locally injected muscles of mdx mice. We demonstrate that LNA/2’OMe AONs with a 30% LNA composition were significantly more potent in inducing exon skipping and dystrophin restoration in treated mdx muscles, compared to a previously tested 2’OMe AON and LNA/2’OMe chimeras with lower or higher LNA compositions. These results underscore the therapeutic potential of LNA/2’OMe AONs, paving the way for further experimentation to evaluate their benefit-toxicity profile following systemic delivery.

scholarly journals Evaluating the potential of novel genetic approaches for the treatment of Duchenne muscular dystrophy

2021 ◽  
Author(s):  
Vratko Himič ◽  
Kay E. Davies
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Structural Integrity ◽  
Viral Vector ◽  
Exon Skipping ◽  
Dystrophin Gene ◽  
Pharmacological Treatments ◽  
Genetic Sequencing ◽  
Reading Frame ◽  
Target Effects

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.

scholarly journals In vivo genome editing in mouse restores dystrophin expression in Duchenne muscular dystrophy patient muscle fibers

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Menglong Chen ◽  
Hui Shi ◽  
Shixue Gou ◽  
Xiaomin Wang ◽  
Lei Li ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Mouse Model ◽  
Genome Editing ◽  
Large Scale ◽  
Gene Editing ◽  
High Efficiency ◽  
Muscle Fibers ◽  
Muscle Cells

Abstract Background Mutations in the DMD gene encoding dystrophin—a critical structural element in muscle cells—cause Duchenne muscular dystrophy (DMD), which is the most common fatal genetic disease. Clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing is a promising strategy for permanently curing DMD. Methods In this study, we developed a novel strategy for reframing DMD mutations via CRISPR-mediated large-scale excision of exons 46–54. We compared this approach with other DMD rescue strategies by using DMD patient-derived primary muscle-derived stem cells (DMD-MDSCs). Furthermore, a patient-derived xenograft (PDX) DMD mouse model was established by transplanting DMD-MDSCs into immunodeficient mice. CRISPR gene editing components were intramuscularly delivered into the mouse model by adeno-associated virus vectors. Results Results demonstrated that the large-scale excision of mutant DMD exons showed high efficiency in restoring dystrophin protein expression. We also confirmed that CRISPR from Prevotella and Francisella 1(Cas12a)-mediated genome editing could correct DMD mutation with the same efficiency as CRISPR-associated protein 9 (Cas9). In addition, more than 10% human DMD muscle fibers expressed dystrophin in the PDX DMD mouse model after treated by the large-scale excision strategies. The restored dystrophin in vivo was functional as demonstrated by the expression of the dystrophin glycoprotein complex member β-dystroglycan. Conclusions We demonstrated that the clinically relevant CRISPR/Cas9 could restore dystrophin in human muscle cells in vivo in the PDX DMD mouse model. This study demonstrated an approach for the application of gene therapy to other genetic diseases.

scholarly journals Autophagy in the heart is enhanced and independent of disease progression in mus musculus dystrophinopathy models

2019 ◽  
Vol 8 ◽  
pp. 204800401987958
Author(s):  
HR Spaulding ◽  
C Ballmann ◽  
JC Quindry ◽  
MB Hudson ◽  
JT Selsby
Keyword(s):  
Skeletal Muscle ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Disease Progression ◽  
Gene Mutations ◽  
Dystrophin Gene ◽  
Mdx Mice ◽  
Dystrophin Deficiency ◽  
Muscle Wasting Disease ◽  
Dystrophin Protein

Background Duchenne muscular dystrophy is a muscle wasting disease caused by dystrophin gene mutations resulting in dysfunctional dystrophin protein. Autophagy, a proteolytic process, is impaired in dystrophic skeletal muscle though little is known about the effect of dystrophin deficiency on autophagy in cardiac muscle. We hypothesized that with disease progression autophagy would become increasingly dysfunctional based upon indirect autophagic markers. Methods Markers of autophagy were measured by western blot in 7-week-old and 17-month-old control (C57) and dystrophic (mdx) hearts. Results Counter to our hypothesis, markers of autophagy were similar between groups. Given these surprising results, two independent experiments were conducted using 14-month-old mdx mice or 10-month-old mdx/Utrn± mice, a more severe model of Duchenne muscular dystrophy. Data from these animals suggest increased autophagosome degradation. Conclusion Together these data suggest that autophagy is not impaired in the dystrophic myocardium as it is in dystrophic skeletal muscle and that disease progression and related injury is independent of autophagic dysfunction.

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