scholarly journals Effects of systemic multiexon skipping with peptide-conjugated morpholinos in the heart of a dog model of Duchenne muscular dystrophy

2017 ◽  
Vol 114 (16) ◽  
pp. 4213-4218 ◽  
Author(s):  
Yusuke Echigoya ◽  
Akinori Nakamura ◽  
Tetsuya Nagata ◽  
Nobuyuki Urasawa ◽  
Kenji Rowel Q. Lim ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cardiac Muscle ◽  
Genetic Disorder ◽  
Cardiac Conduction ◽  
Purkinje Fibers ◽  
Dystrophin Expression ◽  
Dog Model ◽  
Cardiac Purkinje Fibers ◽  
Systemic Treatments

Duchenne muscular dystrophy (DMD) is a lethal genetic disorder caused by an absence of the dystrophin protein in bodywide muscles, including the heart. Cardiomyopathy is a leading cause of death in DMD. Exon skipping via synthetic phosphorodiamidate morpholino oligomers (PMOs) represents one of the most promising therapeutic options, yet PMOs have shown very little efficacy in cardiac muscle. To increase therapeutic potency in cardiac muscle, we tested a next-generation morpholino: arginine-rich, cell-penetrating peptide-conjugated PMOs (PPMOs) in the canine X-linked muscular dystrophy in Japan (CXMDJ) dog model of DMD. A PPMO cocktail designed to skip dystrophin exons 6 and 8 was injected intramuscularly, intracoronarily, or intravenously into CXMDJ dogs. Intravenous injections with PPMOs restored dystrophin expression in the myocardium and cardiac Purkinje fibers, as well as skeletal muscles. Vacuole degeneration of cardiac Purkinje fibers, as seen in DMD patients, was ameliorated in PPMO-treated dogs. Although symptoms and functions in skeletal muscle were not ameliorated by i.v. treatment, electrocardiogram abnormalities (increased Q-amplitude and Q/R ratio) were improved in CXMDJ dogs after intracoronary or i.v. administration. No obvious evidence of toxicity was found in blood tests throughout the monitoring period of one or four systemic treatments with the PPMO cocktail (12 mg/kg/injection). The present study reports the rescue of dystrophin expression and recovery of the conduction system in the heart of dystrophic dogs by PPMO-mediated multiexon skipping. We demonstrate that rescued dystrophin expression in the Purkinje fibers leads to the improvement/prevention of cardiac conduction abnormalities in the dystrophic heart.

Reduced Na+ current in Purkinje fibers explains cardiac conduction defects and arrhythmias in Duchenne muscular dystrophy

2020 ◽  
Vol 318 (6) ◽  
pp. H1436-H1440
Author(s):  
Janine Ebner ◽  
Pavel Uhrin ◽  
Petra L. Szabo ◽  
Attila Kiss ◽  
Bruno K. Podesser ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Cardiac Conduction ◽  
Na Current ◽  
Purkinje Fibers ◽  
Cardiac Purkinje Fibers ◽  
Current Densities ◽  
Ventricular Conduction

Dystrophic cardiac Purkinje fibers have abnormally reduced Na+ current densities. This explains impaired ventricular conduction in the dystrophic heart.

scholarly journals Restoring Dystrophin Expression in Duchenne Muscular Dystrophy: Current Status of Therapeutic Approaches

2019 ◽  
Vol 9 (1) ◽  
pp. 1 ◽  
Author(s):  
Yuko Shimizu-Motohashi ◽  
Hirofumi Komaki ◽  
Norio Motohashi ◽  
Shin’ichi Takeda ◽  
Toshifumi Yokota ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Stop Codon ◽  
Genetic Disorder ◽  
Premature Stop Codon ◽  
Exon Skipping ◽  
Current Status ◽  
Therapeutic Approaches ◽  
Dystrophin Expression

Duchenne muscular dystrophy (DMD), a rare genetic disorder characterized by progressive muscle weakness, is caused by the absence or a decreased amount of the muscle cytoskeletal protein dystrophin. Currently, several therapeutic approaches to cure DMD are being investigated, which can be categorized into two groups: therapies that aim to restore dystrophin expression, and those that aim to compensate for the lack of dystrophin. Therapies that restore dystrophin expression include read-through therapy, exon skipping, vector-mediated gene therapy, and cell therapy. Of these approaches, the most advanced are the read-through and exon skipping therapies. In 2014, ataluren, a drug that can promote ribosomal read-through of mRNA containing a premature stop codon, was conditionally approved in Europe. In 2016, eteplirsen, a morpholino-based chemical capable of skipping exon 51 in premature mRNA, received conditional approval in the USA. Clinical trials on vector-mediated gene therapy carrying micro- and mini- dystrophin are underway. More innovative therapeutic approaches include CRISPR/Cas9-based genome editing and stem cell-based cell therapies. Here we review the current status of therapeutic approaches for DMD, focusing on therapeutic approaches that can restore dystrophin.

scholarly journals Efficacy of Multi-exon Skipping Treatment in Duchenne Muscular Dystrophy Dog Model Neonates

2019 ◽  
Vol 27 (1) ◽  
pp. 76-86 ◽  
Author(s):  
Kenji Rowel Q. Lim ◽  
Yusuke Echigoya ◽  
Tetsuya Nagata ◽  
Mutsuki Kuraoka ◽  
Masanori Kobayashi ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Exon Skipping ◽  
Dog Model

scholarly journals Restoring Dystrophin Expression in Duchenne Muscular Dystrophy Muscle

2011 ◽  
Vol 179 (1) ◽  
pp. 12-22 ◽  
Author(s):  
Eric P. Hoffman ◽  
Abby Bronson ◽  
Arthur A. Levin ◽  
Shin'ichi Takeda ◽  
Toshifumi Yokota ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Dystrophin Expression

scholarly journals Correction of Dystrophin Expression in Cells From Duchenne Muscular Dystrophy Patients Through Genomic Excision of Exon 51 by Zinc Finger Nucleases

2015 ◽  
Vol 23 (3) ◽  
pp. 523-532 ◽  
Author(s):  
David G Ousterout ◽  
Ami M Kabadi ◽  
Pratiksha I Thakore ◽  
Pablo Perez-Pinera ◽  
Matthew T Brown ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Zinc Finger ◽  
Zinc Finger Nucleases ◽  
Dystrophin Expression ◽  
In Cells

A Longitudinal Study of Quantitative Muscle Strength and Functional Motor Ability in Ambulatory Boys with Duchenne Muscular Dystrophy

2021 ◽  
pp. 1-14
Author(s):  
Cathleen E. Buckon ◽  
Susan E. Sienko ◽  
Eileen G. Fowler ◽  
Anita M. Bagley ◽  
Loretta A. Staudt ◽  
...  
Keyword(s):  
Longitudinal Study ◽  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Genetic Disorder ◽  
Knee Extensor ◽  
Standard Of Care ◽  
Rate Of Change ◽  
Isokinetic Dynamometry ◽  
Gross Motor

Background: Duchenne muscular dystrophy (DMD) is an X-linked recessive genetic disorder, that is characterized by progressive muscle degeneration and loss of ambulation between 7–13 years of age. Novel pharmacological agents targeting the genetic defects and disease mechanisms are becoming available; however, corticosteroid (CS) therapy remains the standard of care. Objective: The purpose of this longitudinal study was to elucidate the effect of CS therapy on the rate of muscle strength and gross motor skill decline in boys with DMD and assess the sensitivity of selected outcome measures. Methods: Eighty-four ambulatory boys with DMD (49–180 months), 70 on CS, 14 corticosteroid naïve (NCS), participated in this 8-year multi-site study. Outcomes included; isokinetic dynamometry, the Standing (STD) and Walking/Running/jumping (WRJ) dimensions of the Gross Motor Function Measure (GMFM), and Timed Function Tests (TFTs). Nonlinear mixed modeling procedures determined the rate of change with age and the influence of steroids. Results: Despite CS therapy the rate of decline in strength with age was significant in all muscle groups assessed. CS therapy significantly slowed decline in knee extensor strength, as the NCS group declined at 3x the rate of the CS group. Concurrently, WRJ skills declined in the NCS group at twice the rate of the CS group. 4-stair climb and 10 meter walk/run performance was superior in the boys on CS therapy. Conclusion: CS therapy slowed the rate of muscle strength decline and afforded longer retention of select gross motor skills in boys on CS compared to boys who were NCS. Isokinetic dynamometry, Walk/Run/Jump skills, and select TFTs may prove informative in assessing the efficacy of new therapeutics in ambulatory boys with DMD.

scholarly journals Laminin-111 protein therapy enhances muscle regeneration and repair in the GRMD dog model of Duchenne muscular dystrophy

2019 ◽  
Vol 28 (16) ◽  
pp. 2686-2695 ◽  
Author(s):  
Pamela Barraza-Flores ◽  
Tatiana M Fontelonga ◽  
Ryan D Wuebbles ◽  
Hailey J Hermann ◽  
Andreia M Nunes ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Muscle Strength ◽  
Premature Death ◽  
Muscle Disease ◽  
Muscle Pathology ◽  
Mdx Mouse ◽  
Protein Therapy ◽  
Muscle Fibrosis ◽  
Dog Model

Abstract Duchenne muscular dystrophy (DMD) is a devastating X-linked disease affecting ~1 in 5000 males. DMD patients exhibit progressive muscle degeneration and weakness, leading to loss of ambulation and premature death from cardiopulmonary failure. We previously reported that mouse Laminin-111 (msLam-111) protein could reduce muscle pathology and improve muscle function in the mdx mouse model for DMD. In this study, we examined the ability of msLam-111 to prevent muscle disease progression in the golden retriever muscular dystrophy (GRMD) dog model of DMD. The msLam-111 protein was injected into the cranial tibial muscle compartment of GRMD dogs and muscle strength and pathology were assessed. The results showed that msLam-111 treatment increased muscle fiber regeneration and repair with improved muscle strength and reduced muscle fibrosis in the GRMD model. Together, these findings support the idea that Laminin-111 could serve as a novel protein therapy for the treatment of DMD.

scholarly journals In vivo non-invasive monitoring of dystrophin correction in a new Duchenne muscular dystrophy reporter mouse

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Leonela Amoasii ◽  
Hui Li ◽  
Yu Zhang ◽  
Yi-Li Min ◽  
Efrain Sanchez-Ortiz ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Genetic Disorder ◽  
Dystrophin Gene ◽  
Luciferase Reporter ◽  
Luciferase Expression ◽  
Gene Correction ◽  
Reading Frame ◽  
Non Invasive

Abstract Duchenne muscular dystrophy (DMD) is a fatal genetic disorder caused by mutations in the dystrophin gene. To enable the non-invasive analysis of DMD gene correction strategies in vivo, we introduced a luciferase reporter in-frame with the C-terminus of the dystrophin gene in mice. Expression of this reporter mimics endogenous dystrophin expression and DMD mutations that disrupt the dystrophin open reading frame extinguish luciferase expression. We evaluated the correction of the dystrophin reading frame coupled to luciferase in mice lacking exon 50, a common mutational hotspot, after delivery of CRISPR/Cas9 gene editing machinery with adeno-associated virus. Bioluminescence monitoring revealed efficient and rapid restoration of dystrophin protein expression in affected skeletal muscles and the heart. Our results provide a sensitive non-invasive means of monitoring dystrophin correction in mouse models of DMD and offer a platform for testing different strategies for amelioration of DMD pathogenesis.

Eteplirsen treatment for Duchenne muscular dystrophy

Neurology ◽  
2018 ◽  
Vol 90 (24) ◽  
pp. e2146-e2154 ◽  
Author(s):  
Jay S. Charleston ◽  
Frederick J. Schnell ◽  
Johannes Dworzak ◽  
Cas Donoghue ◽  
Sarah Lewis ◽  
...  
Keyword(s):  
Duchenne Muscular Dystrophy ◽  
Muscular Dystrophy ◽  
Western Blot ◽  
Reverse Transcription ◽  
Exon Skipping ◽  
Fold Increase ◽  
Cell Penetration ◽  
Reverse Transcription Pcr ◽  
Dystrophin Expression ◽  
Immunofluorescence Intensity

ObjectiveTo describe the quantification of novel dystrophin production in patients with Duchenne muscular dystrophy (DMD) after long-term treatment with eteplirsen.MethodsClinical study 202 was an observational, open-label extension of the randomized, controlled study 201 assessing the safety and efficacy of eteplirsen in patients with DMD with a confirmed mutation in the DMD gene amenable to correction by skipping of exon 51. Patients received once-weekly IV doses of eteplirsen 30 or 50 mg/kg. Upper extremity muscle biopsy samples were collected at combined study week 180, blinded, and assessed for dystrophin-related content by Western blot, Bioquant software measurement of dystrophin-associated immunofluorescence intensity, and percent dystrophin-positive fibers (PDPF). Results were contrasted with matched untreated biopsies from patients with DMD. Reverse transcription PCR followed by Sanger sequencing of newly formed slice junctions was used to confirm the mechanism of action of eteplirsen.ResultsReverse transcription PCR analysis and sequencing of the newly formed splice junction confirmed that 100% of treated patients displayed the expected skipped exon 51 sequence. In treated patients vs untreated controls, Western blot analysis of dystrophin content demonstrated an 11.6-fold increase (p = 0.007), and PDPF analysis demonstrated a 7.4-fold increase (p < 0.001). The PDPF findings were confirmed in a re-examination of the sample (15.5-fold increase, p < 0.001). Dystrophin immunofluorescence intensity was 2.4-fold greater in treated patients than in untreated controls (p < 0.001).ConclusionTaken together, the 4 assays, each based on unique evaluation mechanisms, provided evidence of eteplirsen muscle cell penetration, exon skipping, and induction of novel dystrophin expression.Classification of evidenceThis study provides Class II evidence of the muscle cell penetration, exon skipping, and induction of novel dystrophin expression by eteplirsen, as confirmed by 4 assays.

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