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Dubuisson N, Versele R, Planchon C, Selvais CM, Noel L, Abou-Samra M, Davis-López de Carrizosa MA. Histological Methods to Assess Skeletal Muscle Degeneration and Regeneration in Duchenne Muscular Dystrophy. Int J Mol Sci 2022; 23:16080. [PMID: 36555721 PMCID: PMC9786356 DOI: 10.3390/ijms232416080] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/09/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive disease caused by the loss of function of the protein dystrophin. This protein contributes to the stabilisation of striated cells during contraction, as it anchors the cytoskeleton with components of the extracellular matrix through the dystrophin-associated protein complex (DAPC). Moreover, absence of the functional protein affects the expression and function of proteins within the DAPC, leading to molecular events responsible for myofibre damage, muscle weakening, disability and, eventually, premature death. Presently, there is no cure for DMD, but different treatments help manage some of the symptoms. Advances in genetic and exon-skipping therapies are the most promising intervention, the safety and efficiency of which are tested in animal models. In addition to in vivo functional tests, ex vivo molecular evaluation aids assess to what extent the therapy has contributed to the regenerative process. In this regard, the later advances in microscopy and image acquisition systems and the current expansion of antibodies for immunohistological evaluation together with the development of different spectrum fluorescent dyes have made histology a crucial tool. Nevertheless, the complexity of the molecular events that take place in dystrophic muscles, together with the rise of a multitude of markers for each of the phases of the process, makes the histological assessment a challenging task. Therefore, here, we summarise and explain the rationale behind different histological techniques used in the literature to assess degeneration and regeneration in the field of dystrophinopathies, focusing especially on those related to DMD.
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Affiliation(s)
- Nicolas Dubuisson
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
- Neuromuscular Reference Center, Cliniques Universitaires Saint-Luc (CUSL), Avenue Hippocrate 10, 1200 Brussels, Belgium
| | - Romain Versele
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Chloé Planchon
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Camille M. Selvais
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Laurence Noel
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Michel Abou-Samra
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - María A. Davis-López de Carrizosa
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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Bengtsson NE, Crudele JM, Klaiman JM, Halbert CL, Hauschka SD, Chamberlain JS. Comparison of dystrophin expression following gene editing and gene replacement in an aged preclinical DMD animal model. Mol Ther 2022; 30:2176-2185. [PMID: 35143959 PMCID: PMC9171147 DOI: 10.1016/j.ymthe.2022.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 01/13/2022] [Accepted: 02/03/2022] [Indexed: 11/30/2022] Open
Abstract
Gene editing has shown promise for correcting or bypassing dystrophin mutations in Duchenne muscular dystrophy (DMD). However, preclinical studies have focused on young animals with limited muscle fibrosis and wasting, thereby favoring muscle transduction, myonuclear editing, and prevention of disease progression. Here, we explore muscle-specific dystrophin gene editing following intramuscular delivery of AAV6:CK8e-CRISPR/SaCas9 in 3- and 8-year-old dystrophic CXMD dogs and provide a qualitative comparison to AAV6:CK8e-micro-dystrophin gene replacement at 6 weeks post-treatment. Gene editing restored the dystrophin reading frame in ∼1.3% of genomes and in up to 4.0% of dystrophin transcripts following excision of a 105-kb mutation containing region spanning exons 6-8. However, resulting dystrophin expression levels and effects on muscle pathology were greater with the use of micro-dystrophin gene transfer. This study demonstrates that our muscle-specific multi-exon deletion strategy can correct a frequently mutated region of the dystrophin gene in an aged large animal DMD model, but underscores that further enhancements are required to reach efficiencies comparable to AAV micro-dystrophin. Our observations also indicate that treatment efficacy and state of muscle pathology at the time of intervention are linked, suggesting the need for additional methodological optimizations related to age and disease progression to achieve relevant clinical translation of CRISPR-based therapies to all DMD patients.
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Affiliation(s)
- Niclas E Bengtsson
- Department of Neurology, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA.
| | - Julie M Crudele
- Department of Neurology, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA
| | - Jordan M Klaiman
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Department of Rehabilitation Medicine, University of Washington School of Medicine, Seattle, WA 98109-8055, USA
| | - Christine L Halbert
- Department of Neurology, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA
| | - Stephen D Hauschka
- Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98109-8055, USA
| | - Jeffrey S Chamberlain
- Department of Neurology, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Senator Paul D. Wellstone Muscular Dystrophy Specialized Research Center, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Department of Biochemistry, University of Washington School of Medicine, Seattle, WA 98109-8055, USA; Department of Medicine, University of Washington School of Medicine, Seattle, WA 98109-8055, USA
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Ebrahimi M, Lad H, Fusto A, Tiper Y, Datye A, Nguyen CT, Jacques E, Moyle LA, Nguyen T, Musgrave B, Chávez-Madero C, Bigot A, Chen C, Turner S, Stewart BA, Pegoraro E, Vitiello L, Gilbert PM. De novo revertant fiber formation and therapy testing in a 3D culture model of Duchenne muscular dystrophy skeletal muscle. Acta Biomater 2021; 132:227-244. [PMID: 34048976 DOI: 10.1016/j.actbio.2021.05.020] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 05/16/2021] [Accepted: 05/18/2021] [Indexed: 12/18/2022]
Abstract
The biological basis of Duchenne muscular dystrophy (DMD) pathology is only partially characterized and there are still few disease-modifying therapies available, therein underlying the value of strategies to model and study DMD. Dystrophin, the causative gene of DMD, is responsible for linking the cytoskeleton of muscle fibers to the extracellular matrix beyond the sarcolemma. We posited that disease-associated phenotypes not yet captured by two-dimensional culture methods would arise by generating multinucleated muscle cells within a three-dimensional (3D) extracellular matrix environment. Herein we report methods to produce 3D human skeletal muscle microtissues (hMMTs) using clonal, immortalized myoblast lines established from healthy and DMD donors. We also established protocols to evaluate immortalized hMMT self-organization and myotube maturation, as well as calcium handling, force generation, membrane stability (i.e., creatine kinase activity and Evans blue dye permeability) and contractile apparatus organization following electrical-stimulation. In examining hMMTs generated with a cell line wherein the dystrophin gene possessed a duplication of exon 2, we observed rare dystrophin-positive myotubes, which were not seen in 2D cultures. Further, we show that treating DMD hMMTs with a β1-integrin activating antibody, improves contractile apparatus maturation and stability. Hence, immortalized myoblast-derived DMD hMMTs offer a pre-clinical system with which to investigate the potential of duplicated exon skipping strategies and those that protect muscle cells from contraction-induced injury. STATEMENT OF SIGNIFICANCE: Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disorder that is caused by mutation of the dystrophin gene. The biological basis of DMD pathology is only partially characterized and there is no cure for this fatal disease. Here we report a method to produce 3D human skeletal muscle microtissues (hMMTs) using immortalized human DMD and healthy myoblasts. Morphological and functional assessment revealed DMD-associated pathophysiology including impaired calcium handling and de novo formation of dystrophin-positive revertant muscle cells in immortalized DMD hMMTs harbouring an exon 2 duplication, a feature of many DMD patients that has not been recapitulated in culture prior to this report. We further demonstrate that this "DMD in a dish" system can be used as a pre-clinical assay to test a putative DMD therapeutic and study the mechanism of action.
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Affiliation(s)
- Majid Ebrahimi
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Heta Lad
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Aurora Fusto
- Department of Neuroscience, University of Padua, Padua, 35128, Italy
| | - Yekaterina Tiper
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Asiman Datye
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Christine T Nguyen
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S3G5, Canada; Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L1C6, Canada
| | - Erik Jacques
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Louise A Moyle
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Thy Nguyen
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Brennen Musgrave
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Carolina Chávez-Madero
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada
| | - Anne Bigot
- Sorbonne Universite, INSERM, Association Institut de Myologie, Centre de Recherche en Myologie, Paris UMRS974, France
| | - Chun Chen
- Pliant Therapeutics, Inc, South San Francisco, California 94080, USA
| | - Scott Turner
- Pliant Therapeutics, Inc, South San Francisco, California 94080, USA
| | - Bryan A Stewart
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S3G5, Canada; Department of Biology, University of Toronto Mississauga, Mississauga, ON L5L1C6, Canada
| | - Elena Pegoraro
- Department of Neuroscience, University of Padua, Padua, 35128, Italy
| | - Libero Vitiello
- Department of Biology, University of Padua, Padua 35131, Italy; Interuniversity Institute of Myology (IIM), Italy
| | - Penney M Gilbert
- Donnelly Centre, University of Toronto, Toronto, ON M5S3E1, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S3G9, Canada; Department of Cell and Systems Biology, University of Toronto, Toronto, ON M5S3G5, Canada.
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Brunetti B, Muscatello LV, Letko A, Papa V, Cenacchi G, Grillini M, Murgiano L, Jagannathan V, Drögemüller C. X-Linked Duchenne-Type Muscular Dystrophy in Jack Russell Terrier Associated with a Partial Deletion of the Canine DMD Gene. Genes (Basel) 2020; 11:genes11101175. [PMID: 33049940 PMCID: PMC7600251 DOI: 10.3390/genes11101175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 09/30/2020] [Accepted: 10/05/2020] [Indexed: 11/29/2022] Open
Abstract
A 9-month old male Jack Russell Terrier started showing paraparesis of the hindlimbs after a walk. Hospitalized, the dog went into cardiac arrest, and later died. Necroscopic examination revealed a severe thickness of the diaphragm, esophagus, and base of the tongue, leading to the diagnosis of muscular dystrophy. The histology confirmed the marked size variation, regeneration, and fibrosis replacement of the skeletal muscle fibers. Immunohistochemistry demonstrated the absence of dystrophin confirming the diagnosis. Transmission electron microscopy showed disarrangement of skeletal muscle fibers. Finally, whole-genome sequencing identified a ~368kb deletion spanning 19 exons of the canine dystrophin (DMD) gene. This pathogenic loss-of-function variant most likely explains the observed disease phenotype. The X-chromosomal variant was absent in seven controls of the same breed. Most likely, this partial deletion of the DMD gene was either transmitted on the maternal path within the family of the affected dog or arose de novo. This study revealed a spontaneous partial deletion in DMD gene in a Jack Russell Terrier showing a Duchenne-type muscular dystrophy due to non-functional dystrophin.
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Affiliation(s)
- Barbara Brunetti
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Bologna, Italy;
- Correspondence: ; Tel.: +39-051-2097960
| | - Luisa V. Muscatello
- Department of Veterinary Medical Sciences, University of Bologna, 40064 Bologna, Italy;
| | - Anna Letko
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (L.M.); (V.J.); (C.D.)
| | - Valentina Papa
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40138 Bologna, Italy; (V.P.); (G.C.)
| | - Giovanna Cenacchi
- Department of Biomedical and Neuromotor Sciences, University of Bologna, 40138 Bologna, Italy; (V.P.); (G.C.)
| | - Marco Grillini
- Pathology Unit, S Orsola Malpighi Hospital, University of Bologna, 40138 Bologna, Italy;
| | - Leonardo Murgiano
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (L.M.); (V.J.); (C.D.)
- Department of Clinical Sciences & Advanced Medicine, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Vidhya Jagannathan
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (L.M.); (V.J.); (C.D.)
| | - Cord Drögemüller
- Institute of Genetics, Vetsuisse Faculty, University of Bern, 3001 Bern, Switzerland; (A.L.); (L.M.); (V.J.); (C.D.)
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Barthélémy I, Calmels N, Weiss RB, Tiret L, Vulin A, Wein N, Peccate C, Drougard C, Beroud C, Deburgrave N, Thibaud JL, Escriou C, Punzón I, Garcia L, Kaplan JC, Flanigan KM, Leturcq F, Blot S. X-linked muscular dystrophy in a Labrador Retriever strain: phenotypic and molecular characterisation. Skelet Muscle 2020; 10:23. [PMID: 32767978 PMCID: PMC7412789 DOI: 10.1186/s13395-020-00239-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 07/09/2020] [Indexed: 12/24/2022] Open
Abstract
Background Canine models of Duchenne muscular dystrophy (DMD) are a valuable tool to evaluate potential therapies because they faithfully reproduce the human disease. Several cases of dystrophinopathies have been described in canines, but the Golden Retriever muscular dystrophy (GRMD) model remains the most used in preclinical studies. Here, we report a new spontaneous dystrophinopathy in a Labrador Retriever strain, named Labrador Retriever muscular dystrophy (LRMD). Methods A colony of LRMD dogs was established from spontaneous cases. Fourteen LRMD dogs were followed-up and compared to the GRMD standard using several functional tests. The disease causing mutation was studied by several molecular techniques and identified using RNA-sequencing. Results The main clinical features of the GRMD disease were found in LRMD dogs; the functional tests provided data roughly overlapping with those measured in GRMD dogs, with similar inter-individual heterogeneity. The LRMD causal mutation was shown to be a 2.2-Mb inversion disrupting the DMD gene within intron 20 and involving the TMEM47 gene. In skeletal muscle, the Dp71 isoform was ectopically expressed, probably as a consequence of the mutation. We found no evidence of polymorphism in either of the two described modifier genes LTBP4 and Jagged1. No differences were found in Pitpna mRNA expression levels that would explain the inter-individual variability. Conclusions This study provides a full comparative description of a new spontaneous canine model of dystrophinopathy, found to be phenotypically equivalent to the GRMD model. We report a novel large DNA mutation within the DMD gene and provide evidence that LRMD is a relevant model to pinpoint additional DMD modifier genes.
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Affiliation(s)
- Inès Barthélémy
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Nadège Calmels
- Laboratoire de biochimie et génétique moléculaire, hôpital Cochin, AP-HP, université Paris Descartes-Sorbonne Paris Cité, Paris, France.,Laboratoire de Diagnostic Génétique-Institut de Génétique Médicale d'Alsace, Hôpitaux Universitaires de Strasbourg, 1 Place de L'Hôpital, 67091, Strasbourg, France
| | - Robert B Weiss
- Department of Human Genetics, The University of Utah School of Medicine, Salt Lake City, Utah, USA
| | - Laurent Tiret
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Adeline Vulin
- SQY Therapeutics, Université de Versailles Saint-Quentin-en-Yvelines, Montigny le Bretonneux, France
| | - Nicolas Wein
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio, USA.,Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - Cécile Peccate
- SQY Therapeutics, Université de Versailles Saint-Quentin-en-Yvelines, Montigny le Bretonneux, France.,Sorbonne Universités, UPMC Université Paris 06, INSERM UMRS974, Centre de Recherche en Myologie, Institut de Myologie, G.H. Pitié Salpêtrière, Paris, France
| | - Carole Drougard
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Christophe Beroud
- Aix Marseille Université, INSERM, MMG, Bioinformatics & Genetics, Marseille, France.,APHM, Hôpital Timone Enfants, Laboratoire de Génétique Moléculaire, Marseille, France
| | - Nathalie Deburgrave
- Laboratoire de biochimie et génétique moléculaire, hôpital Cochin, AP-HP, université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Jean-Laurent Thibaud
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Catherine Escriou
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Isabel Punzón
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France
| | - Luis Garcia
- Université de Versailles Saint-Quentin-en-Yvelines, U1179 INSERM, UFR des Sciences de la Santé, Montigny le Bretonneux, France
| | - Jean-Claude Kaplan
- Laboratoire de biochimie et génétique moléculaire, hôpital Cochin, AP-HP, université Paris Descartes-Sorbonne Paris Cité, Paris, France
| | - Kevin M Flanigan
- The Center for Gene Therapy, Nationwide Children's Hospital, The Ohio State University, Columbus, Ohio, USA.,Department of Pediatrics, The Ohio State University, Columbus, Ohio, USA
| | - France Leturcq
- Laboratoire de biochimie et génétique moléculaire, hôpital Cochin, AP-HP, université Paris Descartes-Sorbonne Paris Cité, Paris, France.,Sorbonne Universités, UPMC Université Paris 06, INSERM UMRS974, Centre de Recherche en Myologie, Institut de Myologie, G.H. Pitié Salpêtrière, Paris, France
| | - Stéphane Blot
- U955 - IMRB, Team 10 - Biology of the neuromuscular system, Inserm, UPEC, EFS, Ecole nationale vétérinaire d'Alfort, 94700, Maisons-Alfort, France.
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Non-immunogenic utrophin gene therapy for the treatment of muscular dystrophy animal models. Nat Med 2019; 25:1505-1511. [PMID: 31591596 DOI: 10.1038/s41591-019-0594-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Accepted: 08/20/2019] [Indexed: 12/16/2022]
Abstract
The essential product of the Duchenne muscular dystrophy (DMD) gene is dystrophin1, a rod-like protein2 that protects striated myocytes from contraction-induced injury3,4. Dystrophin-related protein (or utrophin) retains most of the structural and protein binding elements of dystrophin5. Importantly, normal thymic expression in DMD patients6 should protect utrophin by central immunologic tolerance. We designed a codon-optimized, synthetic transgene encoding a miniaturized utrophin (µUtro), deliverable by adeno-associated virus (AAV) vectors. Here, we show that µUtro is a highly functional, non-immunogenic substitute for dystrophin, preventing the most deleterious histological and physiological aspects of muscular dystrophy in small and large animal models. Following systemic administration of an AAV-µUtro to neonatal dystrophin-deficient mdx mice, histological and biochemical markers of myonecrosis and regeneration are completely suppressed throughout growth to adult weight. In the dystrophin-deficient golden retriever model, µUtro non-toxically prevented myonecrosis, even in the most powerful muscles. In a stringent test of immunogenicity, focal expression of µUtro in the deletional-null German shorthaired pointer model produced no evidence of cell-mediated immunity, in contrast to the robust T cell response against similarly constructed µDystrophin (µDystro). These findings support a model in which utrophin-derived therapies might be used to treat clinical dystrophin deficiency, with a favorable immunologic profile and preserved function in the face of extreme miniaturization.
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Shrader SM, Jung S, Denney TS, Smith BF. Characterization of Australian Labradoodle dystrophinopathy. Neuromuscul Disord 2018; 28:927-937. [PMID: 30286978 DOI: 10.1016/j.nmd.2018.08.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 08/05/2018] [Accepted: 08/23/2018] [Indexed: 12/22/2022]
Abstract
In humans, dystrophin mutations cause the X-linked recessive disorder known as Duchenne muscular dystrophy (DMD). These mutations result in skeletal and cardiac muscle damage with mortality increasingly associated with cardiomyopathy. We have identified a novel dystrophin mutation in exon 21 in a line of Australian Labradoodles; affected dogs develop progressive clinical signs including poor weight gain and weight loss, gait abnormalities, exercise intolerance, skeletal muscle atrophy, macroglossa, ptyalism, dysphagia, kyphosis, and a plantigrade stance. Echocardiographic abnormalities include hyperechoic foci in the left ventricular papillary muscles, septal hypokinesis, and decreased left ventricular systolic and diastolic volume and internal diameter. Holter recordings found a Mobitz type II second-degree atrioventricular (AV) block in one affected dog. Analysis of phosphocreatine-to-ATP ratios (PCr/ATP) (obtained via cardiac magnetic resonance imaging and spectroscopy evaluation), found no statistically significant difference in the mean PCr/ATP between groups. Histopathologic skeletal muscle changes included fibrofatty infiltration, myocyte degeneration, necrosis, and regeneration, lymphohistiocytic inflammation, and mineralization; cardiac changes were limited to a focal area of mineralization adjacent to the sinoatrial node in the dog with a second-degree AV block. Due to rapidly progressive clinical signs, a severe phenotype, and potential for cardiac involvement, Australian Labradoodle dystrophinopathy may be a useful model to further study DMD pathogenesis.
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Affiliation(s)
- Stephanie M Shrader
- Department of Pathobiology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, USA.
| | - SeungWoo Jung
- Department of Clinical Sciences, Auburn University College of Veterinary Medicine, Auburn, AL 36849, USA
| | - Thomas S Denney
- Department of Electrical and Computer Engineering, Auburn University, Auburn, AL 36849, USA; Auburn University MRI Research Center, Auburn, AL 36849, USA
| | - Bruce F Smith
- Department of Pathobiology, Auburn University College of Veterinary Medicine, Auburn, AL 36849, USA; Scott-Ritchey Research Center, Auburn University College of Veterinary Medicine, Auburn, AL 36849, USA
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Clinical and genetic characterisation of dystrophin-deficient muscular dystrophy in a family of Miniature Poodle dogs. PLoS One 2018; 13:e0193372. [PMID: 29474464 PMCID: PMC5825102 DOI: 10.1371/journal.pone.0193372] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/08/2018] [Indexed: 11/19/2022] Open
Abstract
Four full-sibling intact male Miniature Poodles were evaluated at 4–19 months of age. One was clinically normal and three were affected. All affected dogs were reluctant to exercise and had generalised muscle atrophy, a stiff gait and a markedly elevated serum creatine kinase activity. Two affected dogs also showed poor development, learning difficulties and episodes of abnormal behaviour. In these two dogs, investigations into forebrain structural and metabolic diseases were unremarkable; electromyography demonstrated fibrillation potentials and complex repetitive discharges in the infraspinatus, supraspinatus and epaxial muscles. Histopathological, immunohistochemical and immunoblotting analyses of muscle biopsies were consistent with dystrophin-deficient muscular dystrophy. DNA samples were obtained from all four full-sibling male Poodles, a healthy female littermate and the dam, which was clinically normal. Whole genome sequencing of one affected dog revealed a >5 Mb deletion on the X chromosome, encompassing the entire DMD gene. The exact deletion breakpoints could not be experimentally ascertained, but we confirmed that this region was deleted in all affected males, but not in the unaffected dogs. Quantitative polymerase chain reaction confirmed all three affected males were hemizygous for the mutant X chromosome, while the wildtype chromosome was observed in the unaffected male littermate. The female littermate and the dam were both heterozygous for the mutant chromosome. Forty-four Miniature Poodles from the general population were screened for the mutation and were homozygous for the wildtype chromosome. The finding represents a naturally-occurring mutation causing dystrophin-deficient muscular dystrophy in the dog.
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Abstract
Duchenne muscular dystrophy (DMD) is an X-linked disease caused by mutations in the DMD gene and loss of the protein dystrophin. The absence of dystrophin leads to myofiber membrane fragility and necrosis, with eventual muscle atrophy and contractures. Affected boys typically die in their second or third decade due to either respiratory failure or cardiomyopathy. Despite extensive attempts to develop definitive therapies for DMD, the standard of care remains prednisone, which has only palliative benefits. Animal models, mainly the mdx mouse and golden retriever muscular dystrophy (GRMD) dog, have played a key role in studies of DMD pathogenesis and treatment development. Because the GRMD clinical syndrome is more severe than in mice, better aligning with the progressive course of DMD, canine studies may translate better to humans. The original founder dog for all GRMD colonies worldwide was identified in the early 1980s before the discovery of the DMD gene and dystrophin. Accordingly, analogies to DMD were initially drawn based on similar clinical features, ranging from the X-linked pattern of inheritance to overlapping histopathologic lesions. Confirmation of genetic homology between DMD and GRMD came with identification of the underlying GRMD mutation, a single nucleotide change that leads to exon skipping and an out-of-frame DMD transcript. GRMD colonies have subsequently been established to conduct pathogenetic and preclinical treatment studies. Simultaneous with the onset of GRMD treatment trials, phenotypic biomarkers were developed, allowing definitive characterization of treatment effect. Importantly, GRMD studies have not always substantiated findings from mdx mice and have sometimes identified serious treatment side effects. While the GRMD model may be more clinically relevant than the mdx mouse, usage has been limited by practical considerations related to expense and the number of dogs available. This further complicates ongoing broader concerns about the poor rate of translation of animal model preclinical studies to humans with analogous diseases. Accordingly, in performing GRMD trials, special attention must be paid to experimental design to align with the approach used in DMD clinical trials. This review provides context for the GRMD model, beginning with its original description and extending to its use in preclinical trials.
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Affiliation(s)
- Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, Mail Stop 4458, College Station, TX, 77843-4458, USA.
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VanBelzen DJ, Malik AS, Henthorn PS, Kornegay JN, Stedman HH. Mechanism of Deletion Removing All Dystrophin Exons in a Canine Model for DMD Implicates Concerted Evolution of X Chromosome Pseudogenes. Mol Ther Methods Clin Dev 2017; 4:62-71. [PMID: 28344992 PMCID: PMC5363321 DOI: 10.1016/j.omtm.2016.12.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 12/07/2016] [Indexed: 01/19/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a lethal, X-linked, muscle-wasting disorder caused by mutations in the large, 2.4-Mb dystrophin gene. The majority of DMD-causing mutations are sporadic, multi-exon, frameshifting deletions, with the potential for variable immunological tolerance to the dystrophin protein from patient to patient. While systemic gene therapy holds promise in the treatment of DMD, immune responses to vectors and transgenes must first be rigorously evaluated in informative preclinical models to ensure patient safety. A widely used canine model for DMD, golden retriever muscular dystrophy, expresses detectable amounts of near full-length dystrophin due to alternative splicing around an intronic point mutation, thereby confounding the interpretation of immune responses to dystrophin-derived gene therapies. Here we characterize a naturally occurring deletion in a dystrophin-null canine, the German shorthaired pointer. The deletion spans 5.6 Mb of the X chromosome and encompasses all coding exons of the DMD and TMEM47 genes. The sequences surrounding the deletion breakpoints are virtually identical, suggesting that the deletion occurred through a homologous recombination event. Interestingly, the deletion breakpoints are within loci that are syntenically conserved among mammals, yet the high homology among this subset of ferritin-like loci is unique to the canine genome, suggesting lineage-specific concerted evolution of these atypical sequence elements.
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Affiliation(s)
- D. Jake VanBelzen
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Alock S. Malik
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Paula S. Henthorn
- Section of Medical Genetics, University of Pennsylvania School of Veterinary Medicine, Philadelphia, PA 19104, USA
| | - Joe N. Kornegay
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843, USA
| | - Hansell H. Stedman
- Department of Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
- Corporal Michael Crescenz Veterans Administration Medical Center, Philadelphia, PA 19104, USA
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Nghiem PP, Bello L, Balog-Alvarez C, López SM, Bettis A, Barnett H, Hernandez B, Schatzberg SJ, Piercy RJ, Kornegay JN. Whole genome sequencing reveals a 7 base-pair deletion in DMD exon 42 in a dog with muscular dystrophy. Mamm Genome 2016; 28:106-113. [PMID: 28028563 PMCID: PMC5371640 DOI: 10.1007/s00335-016-9675-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 12/07/2016] [Indexed: 01/03/2023]
Abstract
Dystrophin is a key cytoskeletal protein coded by the Duchenne muscular dystrophy (DMD) gene located on the X-chromosome. Truncating mutations in the DMD gene cause loss of dystrophin and the classical DMD clinical syndrome. Spontaneous DMD gene mutations and associated phenotypes occur in several other species. The mdx mouse model and the golden retriever muscular dystrophy (GRMD) canine model have been used extensively to study DMD disease pathogenesis and show efficacy and side effects of putative treatments. Certain DMD gene mutations in high-risk, the so-called hot spot areas can be particularly helpful in modeling molecular therapies. Identification of specific mutations has been greatly enhanced by new genomic methods. Whole genome, next generation sequencing (WGS) has been recently used to define DMD patient mutations, but has not been used in dystrophic dogs. A dystrophin-deficient Cavalier King Charles Spaniel (CKCS) dog was evaluated at the functional, histopathological, biochemical, and molecular level. The affected dog's phenotype was compared to the previously reported canine dystrophinopathies. WGS was then used to detect a 7 base pair deletion in DMD exon 42 (c.6051-6057delTCTCAAT mRNA), predicting a frameshift in gene transcription and truncation of dystrophin protein translation. The deletion was confirmed with conventional PCR and Sanger sequencing. This mutation is in a secondary DMD gene hotspot area distinct from the one identified earlier at the 5' donor splice site of intron 50 in the CKCS breed.
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Affiliation(s)
- Peter P Nghiem
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA.
| | - Luca Bello
- Department of Neurosciences, University of Padova, Via Giustiniani 5, 35128, Padova, Italy
| | - Cindy Balog-Alvarez
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Sara Mata López
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Amanda Bettis
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Heather Barnett
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Briana Hernandez
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
| | - Scott J Schatzberg
- Veterinary Emergency and Specialty Center of Santa Fe, 2001 Vivigen Way, Santa Fe, NM, 87505, USA
| | - Richard J Piercy
- Department of Clinical Sciences and Services, Royal Veterinary College, London, UK
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences (Mail Stop 4458), College of Veterinary Medicine, Texas A&M University, College Station, TX, 77843-4458, USA
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Abstract
Duchenne muscular dystrophy is a progressive, fatal, X-linked disease caused by a failure to accumulate the cytoskeletal protein dystrophin. This disease has been studied using a variety of animal models including fish, mice, rats, and dogs. While these models have contributed substantially to our mechanistic understanding of the disease and disease progression, limitations inherent to each model have slowed the clinical advancement of therapies, which necessitates the development of novel large-animal models. Several porcine dystrophin-deficient models have been identified, although disease severity may be so severe as to limit their potential contributions to the field. We have recently identified and completed the initial characterization of a natural porcine model of dystrophin insufficiency. Muscles from these animals display characteristic focal necrosis concomitant with decreased abundance and localization of dystrophin-glycoprotein complex components. These pigs recapitulate many of the cardinal features of muscular dystrophy, have elevated serum creatine kinase activity, and preliminarily appear to display altered locomotion. They also suffer from sudden death preceded by EKG abnormalities. Pig dystrophinopathy models could allow refinement of dosing strategies in human-sized animals in preparation for clinical trials. From an animal handling perspective, these pigs can generally be treated normally, with the understanding that acute stress can lead to sudden death. In summary, the ability to create genetically modified pig models and the serendipitous discovery of genetic disease in the swine industry has resulted in the emergence of new animal tools to facilitate the critical objective of improving the quality and length of life for boys afflicted with such a devastating disease.
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Affiliation(s)
- Joshua T Selsby
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Jason W Ross
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Dan Nonneman
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
| | - Katrin Hollinger
- Joshua T. Selsby, PhD, and Jason W. Ross, PhD are associate professors of Animal Science at Iowa State University, Ames, IA 50011. Dan Nonneman, PhD, is a research molecular biologist at the USDA, ARS, U.S. Meat Animal Research Center, Clay Center, NE 68933. Katrin Hollinger, PhD, was a graduate student in Genetics at Iowa State University, Ames, IA 50011
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Kornegay JN, Spurney CF, Nghiem PP, Brinkmeyer-Langford CL, Hoffman EP, Nagaraju K. Pharmacologic management of Duchenne muscular dystrophy: target identification and preclinical trials. ILAR J 2015; 55:119-49. [PMID: 24936034 DOI: 10.1093/ilar/ilu011] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked human disorder in which absence of the protein dystrophin causes degeneration of skeletal and cardiac muscle. For the sake of treatment development, over and above definitive genetic and cell-based therapies, there is considerable interest in drugs that target downstream disease mechanisms. Drug candidates have typically been chosen based on the nature of pathologic lesions and presumed underlying mechanisms and then tested in animal models. Mammalian dystrophinopathies have been characterized in mice (mdx mouse) and dogs (golden retriever muscular dystrophy [GRMD]). Despite promising results in the mdx mouse, some therapies have not shown efficacy in DMD. Although the GRMD model offers a higher hurdle for translation, dogs have primarily been used to test genetic and cellular therapies where there is greater risk. Failed translation of animal studies to DMD raises questions about the propriety of methods and models used to identify drug targets and test efficacy of pharmacologic intervention. The mdx mouse and GRMD dog are genetically homologous to DMD but not necessarily analogous. Subcellular species differences are undoubtedly magnified at the whole-body level in clinical trials. This problem is compounded by disparate cultures in clinical trials and preclinical studies, pointing to a need for greater rigor and transparency in animal experiments. Molecular assays such as mRNA arrays and genome-wide association studies allow identification of genetic drug targets more closely tied to disease pathogenesis. Genes in which polymorphisms have been directly linked to DMD disease progression, as with osteopontin, are particularly attractive targets.
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Brinkmeyer-Langford C, Kornegay JN. Comparative Genomics of X-linked Muscular Dystrophies: The Golden Retriever Model. Curr Genomics 2014; 14:330-42. [PMID: 24403852 PMCID: PMC3763684 DOI: 10.2174/13892029113149990004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/16/2013] [Accepted: 07/19/2013] [Indexed: 12/30/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating disease that dramatically decreases the lifespan and abilities of affected young people. The primary molecular cause of the disease is the absence of functional dystrophin protein, which is critical to proper muscle function. Those with DMD vary in disease presentation and dystrophin mutation; the same causal mutation may be associated with drastically different levels of disease severity. Also contributing to this variation are the influences of additional modifying genes and/or changes in functional elements governing such modifiers. This genetic heterogeneity complicates the efficacy of treatment methods and to date medical interventions are limited to treating symptoms. Animal models of DMD have been instrumental in teasing out the intricacies of DMD disease and hold great promise for advancing knowledge of its variable presentation and treatment. This review addresses the utility of comparative genomics in elucidating the complex background behind phenotypic variation in a canine model of DMD, Golden Retriever muscular dystrophy (GRMD). This knowledge can be exploited in the development of improved, more personalized treatments for DMD patients, such as therapies that can be tailor-matched to the disease course and genomic background of individual patients.
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Affiliation(s)
- Candice Brinkmeyer-Langford
- Texas A&M University College of Veterinary Medicine, Dept. of Veterinary Integrative Biosciences - Mailstop 4458, College Station, Texas, U.S.A. 77843-4458
| | - Joe N Kornegay
- Texas A&M University College of Veterinary Medicine, Dept. of Veterinary Integrative Biosciences - Mailstop 4458, College Station, Texas, U.S.A. 77843-4458
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Revertant fibers in the mdx murine model of Duchenne muscular dystrophy: an age- and muscle-related reappraisal. PLoS One 2013; 8:e72147. [PMID: 24015212 PMCID: PMC3756063 DOI: 10.1371/journal.pone.0072147] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 07/05/2013] [Indexed: 11/19/2022] Open
Abstract
Muscles in Duchenne dystrophy patients are characterized by the absence of dystrophin, yet transverse sections show a small percentage of fibers (termed "revertant fibers") positive for dystrophin expression. This phenomenon, whose biological bases have not been fully elucidated, is present also in the murine and canine models of DMD and can confound the evaluation of therapeutic approaches. We analyzed 11 different muscles in a cohort of 40 mdx mice, the most commonly model used in pre-clinical studies, belonging to four age groups; such number of animals allowed us to perform solid ANOVA statistical analysis. We assessed the average number of dystrophin-positive fibers, both absolute and normalized for muscle size, and the correlation between their formation and the ageing process. Our results indicate that various muscles develop different numbers of revertant fibers, with different time trends; besides, they suggest that the biological mechanism(s) behind dystrophin re-expression might not be limited to the early development phases but could actually continue during adulthood. Importantly, such finding was seen also in cardiac muscle, a fact that does not fit into the current hypothesis of the clonal origin of "revertant" myonuclei from satellite cells. This work represents the largest, statistically significant analysis of revertant fibers in mdx mice so far, which can now be used as a reference point for improving the evaluation of therapeutic approaches for DMD. At the same time, it provides new clues about the formation of revertant fibers/cardiomyocytes in dystrophic skeletal and cardiac muscle.
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Konieczny P, Swiderski K, Chamberlain JS. Gene and cell-mediated therapies for muscular dystrophy. Muscle Nerve 2013; 47:649-63. [PMID: 23553671 DOI: 10.1002/mus.23738] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2012] [Indexed: 12/29/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle disorder that affects 1 in 3,500 boys. Despite years of research and considerable progress in understanding the molecular mechanism of the disease and advancement of therapeutic approaches, there is no cure for DMD. The current treatment options are limited to physiotherapy and corticosteroids, and although they provide a substantial improvement in affected children, they only slow the course of the disorder. On a more optimistic note, more recent approaches either significantly alleviate or eliminate muscular dystrophy in murine and canine models of DMD and importantly, many of them are being tested in early phase human clinical trials. This review summarizes advancements that have been made in viral and nonviral gene therapy as well as stem cell therapy for DMD with a focus on the replacement and repair of the affected dystrophin gene.
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Affiliation(s)
- Patryk Konieczny
- Department of Neurology, The University of Washington School of Medicine, Seattle, Washington 98105, USA
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17
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Muscle function recovery in golden retriever muscular dystrophy after AAV1-U7 exon skipping. Mol Ther 2012; 20:2120-33. [PMID: 22968479 DOI: 10.1038/mt.2012.181] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked recessive disorder resulting from lesions of the gene encoding dystrophin. These usually consist of large genomic deletions, the extents of which are not correlated with the severity of the phenotype. Out-of-frame deletions give rise to dystrophin deficiency and severe DMD phenotypes, while internal deletions that produce in-frame mRNAs encoding truncated proteins can lead to a milder myopathy known as Becker muscular dystrophy (BMD). Widespread restoration of dystrophin expression via adeno-associated virus (AAV)-mediated exon skipping has been successfully demonstrated in the mdx mouse model and in cardiac muscle after percutaneous transendocardial delivery in the golden retriever muscular dystrophy dog (GRMD) model. Here, a set of optimized U7snRNAs carrying antisense sequences designed to rescue dystrophin were delivered into GRMD skeletal muscles by AAV1 gene transfer using intramuscular injection or forelimb perfusion. We show sustained correction of the dystrophic phenotype in extended muscle areas and partial recovery of muscle strength. Muscle architecture was improved and fibers displayed the hallmarks of mature and functional units. A 5-year follow-up ruled out immune rejection drawbacks but showed a progressive decline in the number of corrected muscle fibers, likely due to the persistence of a mild dystrophic process such as occurs in BMD phenotypes. Although AAV-mediated exon skipping was shown safe and efficient to rescue a truncated dystrophin, it appears that recurrent treatments would be required to maintain therapeutic benefit ahead of the progression of the disease.
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Wilton SD, Fletcher S. Novel compounds for the treatment of Duchenne muscular dystrophy: emerging therapeutic agents. APPLICATION OF CLINICAL GENETICS 2011; 4:29-44. [PMID: 23776365 PMCID: PMC3681176 DOI: 10.2147/tacg.s8762] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The identification of dystrophin and the causative role of mutations in this gene in Duchenne and Becker muscular dystrophies (D/BMD) was expected to lead to timely development of effective therapies. Despite over 20 years of research, corticosteroids remain the only available pharmacological treatment for DMD, although significant benefits and extended life have resulted from advances in the clinical care and management of DMD individuals. Effective treatment of DMD will require dystrophin restitution in skeletal, cardiac, and smooth muscles and nonmuscle tissues; however, modulation of muscle loss and regeneration has the potential to play an important role in altering the natural history of DMD, particularly in combination with other treatments. Emerging biological, molecular, and small molecule therapeutics are showing promise in ameliorating this devastating disease, and it is anticipated that regulatory environments will need to display some flexibility in order to accommodate the new treatment paradigms.
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Affiliation(s)
- Steve D Wilton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Crawley, Perth, WA, Australia
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Olby NJ, Sharp NJH, Nghiem PE, Keene BW, DeFrancesco TC, Sidley JA, Kornegay JN, Schatzberg SJ. Clinical progression of X-linked muscular dystrophy in two German Shorthaired Pointers. J Am Vet Med Assoc 2011; 238:207-12. [PMID: 21235374 DOI: 10.2460/javma.238.2.207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
CASE DESCRIPTION 2 full-sibling male German Shorthaired Pointer (GSHP) puppies (dogs 1 and 2) with X-linked muscular dystrophy and deletion of the dystrophin gene (gene symbol, DMD) each had poor growth, skeletal muscle atrophy, pelvic limb weakness, episodic collapse, and episodes of coughing. CLINICAL FINDINGS Initial examination revealed stunted growth, brachygnathism, trismus, and diffuse neuromuscular signs in each puppy; clinical signs were more severe in dog 2 than in dog 1. Immunohistochemical analysis revealed a lack of dystrophin protein in both dogs. During the next 3 years, each dog developed hyperinflation of the lungs, hypertrophy of the cervical musculature, and hypertrophy of the lateral head of the triceps brachii muscle. TREATMENT AND OUTCOME Monitoring and supportive care were provided at follow-up visits during an approximately 7-year period. No other specific treatment was provided. Neuromuscular signs in both dogs remained stable after 3 years of age, with dog 2 consistently more severely affected than dog 1. The dogs had multiple episodes of aspiration pneumonia; dogs 1 and 2 were euthanatized at 84 and 93 months of age, respectively. CLINICAL RELEVANCE The clinical course of disease in these dogs was monitored for a longer period than has been monitored in previous reports of dystrophin-deficient dogs. The clinical progression of muscular dystrophy in the 2 GSHPs was compared with that for other breeds and species with dystrophin-deficient conditions, and the potential basis for the phenotypic variation observed between these littermates, along with potential therapeutic ramifications for dogs and humans, was evaluated.
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Affiliation(s)
- Natasha J Olby
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, NC 27606, USA
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Qiao C, Li J, Zheng H, Bogan J, Li J, Yuan Z, Zhang C, Bogan D, Kornegay J, Xiao X. Hydrodynamic limb vein injection of adeno-associated virus serotype 8 vector carrying canine myostatin propeptide gene into normal dogs enhances muscle growth. Hum Gene Ther 2010; 20:1-10. [PMID: 18828709 DOI: 10.1089/hum.2008.135] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Inhibition or blockade of myostatin, a negative growth factor of skeletal muscle, enhances muscle growth and therefore is considered a promising strategy for the treatment of muscle-wasting diseases such as the muscular dystrophies. Previously, we showed that myostatin blockade in both normal and dystrophin-deficient mdx mice by systemic delivery of the myostatin propeptide (MPRO) gene by an adeno-associated virus serotype 8 (AAV8) vector could enhance muscle growth and ameliorate dystrophic lesions. Here, we further investigate whether the muscle growth effect of myostatin blockade can be achieved in dogs by gene transfer. First, we cloned the canine MPRO gene, packaged it in the AAV8 vector, and showed robust muscle-enhancing effects after systemic delivery into neonatal mice. This vector was then further tested in two 3-month-old normal dogs (weighing 9.7 and 6.3 kg). The vector was delivered to one limb by hydrodynamic vein injection, and the contralateral limb served as a control. The delivery procedure was safe, without discernible adverse effects. AAV vector DNA and MPRO gene expression were detected by quantitative polymerase chain reaction, Western blotting, and immunofluorescence staining of muscle biopsies. Overexpression of MPRO resulted in enhanced muscle growth without a cytotoxic T lymphocytic immune response, as evidenced by larger myofibers in multiple muscles, increased muscle volume determined by magnetic resonance imaging, and the lack of CD4+ and CD8+ T cell infiltration in the vector-injected limbs. Our preliminary study thus supports further investigation of this therapeutic strategy in the dystrophin-deficient golden retriever muscular dystrophy dog model.
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Affiliation(s)
- Chunping Qiao
- Division of Molecular Pharmaceutics, University of North Carolina School of Pharmacy, Chapel Hill, NC 27599, USA
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Arechavala-Gomeza V, Kinali M, Feng L, Guglieri M, Edge G, Main M, Hunt D, Lehovsky J, Straub V, Bushby K, Sewry CA, Morgan JE, Muntoni F. Revertant fibres and dystrophin traces in Duchenne muscular dystrophy: Implication for clinical trials. Neuromuscul Disord 2010; 20:295-301. [DOI: 10.1016/j.nmd.2010.03.007] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2009] [Revised: 02/17/2010] [Accepted: 03/05/2010] [Indexed: 10/19/2022]
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Walmsley GL, Arechavala-Gomeza V, Fernandez-Fuente M, Burke MM, Nagel N, Holder A, Stanley R, Chandler K, Marks SL, Muntoni F, Shelton GD, Piercy RJ. A duchenne muscular dystrophy gene hot spot mutation in dystrophin-deficient cavalier king charles spaniels is amenable to exon 51 skipping. PLoS One 2010; 5:e8647. [PMID: 20072625 PMCID: PMC2800183 DOI: 10.1371/journal.pone.0008647] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Accepted: 12/10/2009] [Indexed: 11/26/2022] Open
Abstract
Background Duchenne muscular dystrophy (DMD), which afflicts 1 in 3500 boys, is one of the most common genetic disorders of children. This fatal degenerative condition is caused by an absence or deficiency of dystrophin in striated muscle. Most affected patients have inherited or spontaneous deletions in the dystrophin gene that disrupt the reading frame resulting in unstable truncated products. For these patients, restoration of the reading frame via antisense oligonucleotide-mediated exon skipping is a promising therapeutic approach. The major DMD deletion “hot spot” is found between exons 45 and 53, and skipping exon 51 in particular is predicted to ameliorate the dystrophic phenotype in the greatest number of patients. Currently the mdx mouse is the most widely used animal model of DMD, although its mild phenotype limits its suitability in clinical trials. The Golden Retriever muscular dystrophy (GRMD) model has a severe phenotype, but due to its large size, is expensive to use. Both these models have mutations in regions of the dystrophin gene distant from the commonly mutated DMD “hot spot”. Methodology/Principal Findings Here we describe the severe phenotype, histopathological findings, and molecular analysis of Cavalier King Charles Spaniels with dystrophin-deficient muscular dystrophy (CKCS-MD). The dogs harbour a missense mutation in the 5′ donor splice site of exon 50 that results in deletion of exon 50 in mRNA transcripts and a predicted premature truncation of the translated protein. Antisense oligonucleotide-mediated skipping of exon 51 in cultured myoblasts from an affected dog restored the reading frame and protein expression. Conclusions/Significance Given the small size of the breed, the amiable temperament and the nature of the mutation, we propose that CKCS-MD is a valuable new model for clinical trials of antisense oligonucleotide-induced exon skipping and other therapeutic approaches for DMD.
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Affiliation(s)
- Gemma L. Walmsley
- Department of Veterinary Clinical Sciences, Royal Veterinary College, London, United Kingdom
| | | | - Marta Fernandez-Fuente
- Department of Veterinary Clinical Sciences, Royal Veterinary College, London, United Kingdom
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom
| | - Margaret M. Burke
- Pathology Laboratory, Harefield Hospital, Royal Brompton & Harefield NHS Foundation Trust, Harefield, Middlesex, United Kingdom
| | - Nicole Nagel
- Alphapet Veterinary Clinic, Bognor Regis, West Sussex, United Kingdom
| | - Angela Holder
- Pathology and Infectious Diseases, Royal Veterinary College, London, United Kingdom
| | - Rachael Stanley
- Department of Veterinary Clinical Sciences, Royal Veterinary College, London, United Kingdom
| | - Kate Chandler
- Department of Veterinary Clinical Sciences, Royal Veterinary College, London, United Kingdom
| | - Stanley L. Marks
- Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California Davis, Davis, California, United States of America
| | - Francesco Muntoni
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom
| | - G. Diane Shelton
- Department of Pathology, School of Medicine, University of California San Diego, La Jolla, California, United States of America
| | - Richard J. Piercy
- Department of Veterinary Clinical Sciences, Royal Veterinary College, London, United Kingdom
- Dubowitz Neuromuscular Centre, Institute of Child Health, University College London, United Kingdom
- * E-mail:
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Kinematics of gait in golden retriever muscular dystrophy. Neuromuscul Disord 2009; 20:16-20. [PMID: 19932618 DOI: 10.1016/j.nmd.2009.10.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 10/13/2009] [Accepted: 10/18/2009] [Indexed: 11/16/2022]
Abstract
The goal of this study was to quantify the two-dimensional kinematics of pathologic gait during over-ground walking at a self-selected speed at the stifle (knee) and hock (ankle) joints in six Golden Retriever Muscular Dystrophy (GRMD) dogs and six carrier littermates (controls). We found that GRMD dogs walked significantly slower than controls (p<0.01). At the stifle joint, both groups displayed similar ROM (range of motion), but compared to controls, GRMD dogs walked with the stifle joint relatively more extended. At the hock joint, GRMD dogs displayed less ROM (range of motion) and walked with the joint relatively less flexed compared to controls. We controlled for gait speed in all analyses, so the differences we observed in joint kinematics between groups cannot be attributed solely to the slower walking speed of the GRMD dogs. This is the first kinematic study of gait in the GRMD dog, an important step in using this model in pre-clinical trials.
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The value of mammalian models for duchenne muscular dystrophy in developing therapeutic strategies. Curr Top Dev Biol 2009; 84:431-53. [PMID: 19186250 DOI: 10.1016/s0070-2153(08)00609-1] [Citation(s) in RCA: 99] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy. There is no effective treatment and patients typically die in approximately the third decade. DMD is an X-linked recessive disease caused by mutations in the dystrophin gene. There are three mammalian models of DMD that have been used to understand better the pathogenesis of disease and develop therapeutic strategies. The mdx mouse is the most widely used model of DMD that displays some features of muscle degeneration, but the pathogenesis of disease is comparatively mild. The severity of disease in mice lacking both dystrophin and utrophin is similar to DMD, but one has to account for the discrete functions of utrophin. Canine X-linked muscular dystrophy (cxmd) is the best representation of DMD, but the phenotype of the most widely used golden retriever (GRMD) model is variable, making functional endpoints difficult to ascertain. Although each mammalian model has its limitations, together they have been essential for the development of several treatment strategies for DMD that target dystrophin replacement, disease progression, and muscle regeneration.
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Qiao C, Li J, Zheng H, Bogan J, Li J, Yuan Z, Zhang C, Bogan D, Kornegay J, Xiao X. Hydrodynamic limb vein injection of AAV8 canine myostatin propeptide gene in normal dogs enhances muscle growth. Hum Gene Ther 2008. [DOI: 10.1089/hgt.2008.135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Fall AM, Johnsen R, Honeyman K, Iversen P, Fletcher S, Wilton SD. Induction of revertant fibres in the mdx mouse using antisense oligonucleotides. GENETIC VACCINES AND THERAPY 2006; 4:3. [PMID: 16719929 PMCID: PMC1481566 DOI: 10.1186/1479-0556-4-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Accepted: 05/24/2006] [Indexed: 11/28/2022]
Abstract
Background Duchenne muscular dystrophy is a fatal genetic disorder caused by dystrophin gene mutations that result in premature termination of translation and the absence of functional protein. Despite the primary dystrophin gene lesion, immunostaining studies have shown that at least 50% of DMD patients, mdx mice and a canine model of DMD have rare dystrophin-positive or 'revertant' fibres. Fine epitope mapping has shown that the majority of transcripts responsible for revertant fibres exclude multiple exons, one of which includes the dystrophin mutation. Methods The mdx mouse model of muscular dystrophy has a nonsense mutation in exon 23 of the dystrophin gene. We have shown that antisense oligonucleotides (AOs) can induce the removal of this exon, resulting in an in-frame mRNA transcript encoding a shortened but functional dystrophin protein. To emulate one exonic combination associated with revertant fibres, we target multiple exons for removal by the application of a group of AOs combined as a "cocktail". Results Exons 19–25 were consistently excluded from the dystrophin gene transcript using a cocktail of AOs. This corresponds to an alternatively processed gene transcript that has been sporadically detected in untreated dystrophic mouse muscle, and is presumed to give rise to a revertant dystrophin isoform. The transcript and the resultant correctly localised smaller protein were confirmed by RT-PCR, immunohistochemistry and western blot analysis. Conclusion This work demonstrates the feasibility of AO cocktails to by-pass dystrophin mutation hotspots through multi-exon skipping. Multi-exon skipping could be important in expediting an exon skipping therapy to treat DMD, so that the same AO formulations may be applied to several different mutations within particular domains of the dystrophin gene.
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Affiliation(s)
- Abbie M Fall
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, 6009, Western Australia
| | - Russell Johnsen
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, 6009, Western Australia
| | - Kaite Honeyman
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, 6009, Western Australia
| | | | - Susan Fletcher
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, 6009, Western Australia
| | - Stephen D Wilton
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Nedlands, Perth, 6009, Western Australia
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Wilton SD, Fletcher S. Redirecting Splicing to Address Dystrophin Mutations: Molecular By-pass Surgery. ALTERNATIVE SPLICING AND DISEASE 2006; 44:161-97. [PMID: 17076269 DOI: 10.1007/978-3-540-34449-0_8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mutations in the dystrophin gene that prevent synthesis of a functional protein lead to Duchenne muscular dystrophy (DMD), the most common serious childhood muscular dystrophy. The major isoform is produced in skeletal muscle and the size of the dystrophin gene and complexity of expression have posed great challenges to the development of a therapy for DMD. Considerable progress has been made in the areas of gene and cell replacement, yet it appears that any potential therapy for DMD is still some years away. Other approaches are being considered, and one that has generated substantial interest over the last few years is induced exon skipping. Antisense oligonucleotides have been used to block abnormal splice sites and force pre-mRNA processing back to the normal patterns. This approach is re-interpreted to address the more common dystrophin mutations, where normal splice sites are targeted to induce abnormal splicing, resulting in specific exon exclusion. Selected exon removal during processing of the dystrophin pre-mRNA can by-pass nonsense mutations or restore a disrupted reading frame arising from genomic deletions or duplications. Attributes of the dystrophin gene that have hampered gene replacement therapy may be regarded as positive features for induced exon skipping, which may be regarded as a form of by-pass surgery at the molecular level. In humans, antisense oligonucleotides have been more generally applied to down-regulate specific gene expression, for the treatment of acquired conditions such as malignancies and viral infections. From interesting in vitro experiments several years ago, the dystrophin exon-skipping field has progressed to the stage of planning for clinical trials.
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Affiliation(s)
- Stephen D Wilton
- Experimental Molecular Medicine Group, Centre for Neuromuscular and Neurological Disorders, University of Western Australia
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Childers MK, Staley JT, Kornegay JN, McDonald KS. Skinned single fibers from normal and dystrophin-deficient dogs incur comparable stretch-induced force deficits. Muscle Nerve 2005; 31:768-71. [PMID: 15736272 DOI: 10.1002/mus.20298] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Intact dystrophin-deficient canine muscles were previously shown to incur greater-than-normal stretch-induced force deficits. Here we tested the hypothesis that maximally activated detergent-treated (skinned) single fibers from normal and dystrophin-deficient dogs would incur comparable force deficits after stretch. Skinned cranial sartorius (CS) fibers from dystrophin-deficient and normal dogs were calcium-activated (pCa 4.5) and rapidly stretched. A single 30% stretch induced force deficits of 27.07 +/- 3.9% and 29.7 +/- 4.8% in dystrophin-deficient (n = 22) and normal (n = 18) fibers, respectively. Our data support the hypothesis that maximally activated skinned single fibers from normal and dystrophin-deficient dogs incur comparable force deficits after stretch. Our findings suggest that knowledge of the extent of stretch-induced force deficits following repeated stretch-activations in the GRMD dog may be useful to assess future therapeutic interventions aimed at replacing dystrophin in the sarcolemmal membrane.
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Affiliation(s)
- Martin K Childers
- Department of Physical Medicine and Rehabilitation, School of Medicine, University of Missouri-Columbia, DCO 46.00, One Hospital Drive, Columbia, Missouri 65212, USA.
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Beltran WA, Chahory S, Gnirs K, Escriou C, Blot S, Clerc B. The electroretinographic phenotype of dogs with Golden Retriever muscular dystrophy. Vet Ophthalmol 2001; 4:277-82. [PMID: 11906664 DOI: 10.1046/j.1463-5216.2001.00200.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To characterize the flash electroretinogram (ERG) in the Golden Retriever muscular dystrophy (GRMD) dog and to compare the results with those from a control group of Golden Retrievers. To investigate whether similar abnormalities of the ERG as those found in a majority of human patients with Duchenne muscular dystrophy (DMD) are also observed in the GRMD dog, the canine model for DMD. Animals Five GRMD dogs and five age-matched clinically normal Golden Retrievers. PROCEDURE An ophthalmic examination was carried out prior to performing electroretinography under general anesthesia. Rod, combined rod-cone and oscillatory potentials responses were recorded after dark adaptation. Responses to 30-Hz-flicker were recorded after light adaptation. The ERG responses of the GRMD dogs were compared with those of the control dogs by use of a Wilcoxon signed rank test. RESULTS GRMD dogs had significantly reduced a and b-wave amplitudes after dim white flash stimuli (rod response) and reduced a-wave amplitude after bright white flash stimuli (rod-cone response). CONCLUSION AND CLINICAL RELEVANCE The ERG abnormalities observed in the GRMD dog suggest a dysfunction in the rod signaling pathway. These ERG alterations are different from those observed in human patients with DMD.
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Affiliation(s)
- W A Beltran
- Ophthalmology and Neurology unit, Department of Small Animal and Equine Medicine, National Veterinary College of Alfort, 7 avenue du Général de Gaulle, 94704 Maisons-Alfort, France.
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Fletcher S, Carville KS, Howell JM, Mann CJ, Wilton SD. Evaluation of a short interspersed nucleotide element in the 3' untranslated region of the defective dystrophin gene of dogs with muscular dystrophy. Am J Vet Res 2001; 62:1964-8. [PMID: 11763189 DOI: 10.2460/ajvr.2001.62.1964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVES To determine the distribution of a 231-base pair (bp) element in the dystrophin gene 3' untranslated region (UTR) in a colony of Golden Retrievers with muscular dystrophy and other unrelated dogs and to estimate the frequency of recombination for the canine dystrophin gene. ANIMALS 77 dogs from the Golden Retriever Muscular Dystrophy (GRMD) colony at the Murdoch Veterinary School and 30 unrelated dogs from the Murdoch University Veterinary Clinic. PROCEDURE Samples of blood or hair from dogs were used for amplification of DNA, using primers to the canine dystrophin 3' UTR. RESULTS The DNA from affected dogs generated a larger PCR product than that obtained from clinically normal dogs. Products were cloned and sequenced, and the difference in size was found to be attributable to a 231-bp short interspersed nucleotide element (SINE). The SINE was found in all affected dogs in the colony but not in most unaffected puppies in the colony. Eighteen of 19 dogs in the colony were heterozygous for the GRMD mutation, and 7 of 30 unrelated dogs also were heterozygous for the SINE. CONCLUSION AND CLINICAL RELEVANCE Evidence of recombination between the GRMD mutation and the SINE was observed in only 4 dogs (2 sets of littermates) in the GRMD colony. Incidence of this SINE in a few unrelated dogs suggests that this particular insertion into the dystrophin gene may have been a recent event. The SINE in the dystrophin 3' UTR did not have an apparent influence on dystrophin mRNA concentrations.
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Affiliation(s)
- S Fletcher
- Australian Neuromuscular Research Institute, Queen Elizabeth II Medical Centre, Nedlands, Western Australia
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32
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Mann CJ, Honeyman K, Cheng AJ, Ly T, Lloyd F, Fletcher S, Morgan JE, Partridge TA, Wilton SD. Antisense-induced exon skipping and synthesis of dystrophin in the mdx mouse. Proc Natl Acad Sci U S A 2001; 98:42-7. [PMID: 11120883 PMCID: PMC14541 DOI: 10.1073/pnas.98.1.42] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease arising from defects in the dystrophin gene, typically nonsense or frameshift mutations, that preclude the synthesis of a functional protein. A milder, allelic version of the disease, Becker muscular dystrophy, generally arises from in-frame deletions that allow synthesis of a shorter but still semifunctional protein. Therapies to introduce functional dystrophin into dystrophic tissue through either cell or gene replacement have not been successful to date. We report an alternative approach where 2'-O-methyl antisense oligoribonucleotides have been used to modify processing of the dystrophin pre-mRNA in the mdx mouse model of DMD. By targeting 2'-O-methyl antisense oligoribonucleotides to block motifs involved in normal dystrophin pre-mRNA splicing, we induced excision of exon 23, and the mdx nonsense mutation, without disrupting the reading frame. Exon 23 skipping was first optimized in vitro in transfected H-2K(b)-tsA58 mdx myoblasts and then induced in vivo. Immunohistochemical staining demonstrated the synthesis and correct subsarcolemmal localization of dystrophin and gamma-sarcoglycan in the mdx mouse after intramuscular delivery of antisense oligoribonucleotide:liposome complexes. This approach should reduce the severity of DMD by allowing a dystrophic gene transcript to be modified, such that it can be translated into a Becker-dystrophin-like protein.
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MESH Headings
- Animals
- Base Sequence
- Cells, Cultured
- Cytoskeletal Proteins/metabolism
- Disease Models, Animal
- Dystrophin/biosynthesis
- Dystrophin/genetics
- Exons/genetics
- Fluorescein
- Immunohistochemistry
- Injections, Intramuscular
- Introns/genetics
- Membrane Glycoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Inbred mdx
- Microscopy, Fluorescence
- Molecular Sequence Data
- Muscles/metabolism
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/therapy
- Oligoribonucleotides, Antisense/administration & dosage
- Oligoribonucleotides, Antisense/genetics
- Oligoribonucleotides, Antisense/therapeutic use
- Open Reading Frames/genetics
- Phosphatidylethanolamines/metabolism
- RNA Precursors/genetics
- RNA Precursors/metabolism
- RNA Splicing/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Sarcoglycans
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Affiliation(s)
- C J Mann
- Australian Neuromuscular Research Institute, Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Perth, Western Australia 6009, Australia
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Antisense-induced exon skipping and synthesis of dystrophin in the mdx mouse. Proc Natl Acad Sci U S A 2001. [PMID: 11120883 PMCID: PMC14541 DOI: 10.1073/pnas.011408598] [Citation(s) in RCA: 178] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle wasting disease arising from defects in the dystrophin gene, typically nonsense or frameshift mutations, that preclude the synthesis of a functional protein. A milder, allelic version of the disease, Becker muscular dystrophy, generally arises from in-frame deletions that allow synthesis of a shorter but still semifunctional protein. Therapies to introduce functional dystrophin into dystrophic tissue through either cell or gene replacement have not been successful to date. We report an alternative approach where 2'-O-methyl antisense oligoribonucleotides have been used to modify processing of the dystrophin pre-mRNA in the mdx mouse model of DMD. By targeting 2'-O-methyl antisense oligoribonucleotides to block motifs involved in normal dystrophin pre-mRNA splicing, we induced excision of exon 23, and the mdx nonsense mutation, without disrupting the reading frame. Exon 23 skipping was first optimized in vitro in transfected H-2K(b)-tsA58 mdx myoblasts and then induced in vivo. Immunohistochemical staining demonstrated the synthesis and correct subsarcolemmal localization of dystrophin and gamma-sarcoglycan in the mdx mouse after intramuscular delivery of antisense oligoribonucleotide:liposome complexes. This approach should reduce the severity of DMD by allowing a dystrophic gene transcript to be modified, such that it can be translated into a Becker-dystrophin-like protein.
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Bartlett RJ, Stockinger S, Denis MM, Bartlett WT, Inverardi L, Le TT, thi Man N, Morris GE, Bogan DJ, Metcalf-Bogan J, Kornegay JN. In vivo targeted repair of a point mutation in the canine dystrophin gene by a chimeric RNA/DNA oligonucleotide. Nat Biotechnol 2000; 18:615-22. [PMID: 10835598 DOI: 10.1038/76448] [Citation(s) in RCA: 107] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the canine model of Duchenne muscular dystrophy in golden retrievers (GRMD), a point mutation within the splice acceptor site of intron 6 leads to deletion of exon 7 from the dystrophin mRNA, and the consequent frameshift causes early termination of translation. We have designed a DNA and RNA chimeric oligonucleotide to induce host cell mismatch repair mechanisms and correct the chromosomal mutation to wild type. Direct skeletal muscle injection of the chimeric oligonucleotide into the cranial tibialis compartment of a six-week-old affected male dog, and subsequent analysis of biopsy and necropsy samples, demonstrated in vivo repair of the GRMD mutation that was sustained for 48 weeks. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of exons 5-10 demonstrated increasing levels of exon 7 inclusion with time. An isolated exon 7-specific dystrophin antibody confirmed synthesis of normal-sized dystrophin product and positive localization to the sarcolemma. Chromosomal repair in muscle tissue was confirmed by restriction fragment length polymorphism (RFLP)-PCR and sequencing the PCR product. This work provides evidence for the long-term repair of a specific dystrophin point mutation in muscle of a live animal using a chimeric oligonucleotide.
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Affiliation(s)
- R J Bartlett
- Department of Veterinary Medicine and Surgery, Dalton Cardiovascular Research Center, College of Veterinary Medicine, Columbia, MO 65202, USA.
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Schatzberg SJ, Olby NJ, Breen M, Anderson LV, Langford CF, Dickens HF, Wilton SD, Zeiss CJ, Binns MM, Kornegay JN, Morris GE, Sharp NJ. Molecular analysis of a spontaneous dystrophin 'knockout' dog. Neuromuscul Disord 1999; 9:289-95. [PMID: 10407848 DOI: 10.1016/s0960-8966(99)00011-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have determined the molecular basis for skeletal myopathy and dilated cardiomyopathy in two male German short-haired pointer (GSHP) littermates. Analysis of skeletal muscle demonstrated a complete absence of dystrophin on Western blot analysis. PCR analysis of genomic DNA revealed a deletion encompassing the entire dystrophin gene. Molecular cytogenetic analysis of lymphocytes from the dam and both dystrophic pups confirmed a visible deletion in the p21 region of the affected canine X chromosome. Utrophin is up-regulated in the skeletal muscle, but does not appear to ameliorate the dystrophic canine phenotype. This new canine model should further our understanding of the physiological and biochemical processes in Duchenne muscular dystrophy.
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Affiliation(s)
- S J Schatzberg
- College of Veterinary Medicine, North Carolina State University, Raleigh 27606, USA.
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Anderson LV, Davison K, Moss JA, Young C, Cullen MJ, Walsh J, Johnson MA, Bashir R, Britton S, Keers S, Argov Z, Mahjneh I, Fougerousse F, Beckmann JS, Bushby KM. Dysferlin is a plasma membrane protein and is expressed early in human development. Hum Mol Genet 1999; 8:855-61. [PMID: 10196375 DOI: 10.1093/hmg/8.5.855] [Citation(s) in RCA: 190] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Recently, a single gene, DYSF, has been identified which is mutated in patients with limb-girdle muscular dystrophy type 2B (LGMD2B) and with Miyoshi myopathy (MM). This is of interest because these diseases have been considered as two distinct clinical conditions since different muscle groups are the initial targets. Dysferlin, the protein product of the gene, is a novel molecule without homology to any known mammalian protein. We have now raised a monoclonal antibody to dysferlin and report on the expression of this new protein: immunolabelling with the antibody (designated NCL-hamlet) demonstrated a polypeptide of approximately 230 kDa on western blots of skeletal muscle, with localization to the muscle fibre membrane by microscopy at both the light and electron microscopic level. A specific loss of dysferlin labelling was observed in patients with mutations in the LGMD2B/MM gene. Furthermore, patients with two different frameshifting mutations demonstrated very low levels of immunoreactive protein in a manner reminiscent of the dystrophin expressed in many Duchenne patients. Analysis of human fetal tissue showed that dysferlin was expressed at the earliest stages of development examined, at Carnegie stage 15 or 16 (embryonic age 5-6 weeks). Dysferlin is present, therefore, at a time when the limbs start to show regional differentiation. Lack of dysferlin at this critical time may contribute to the pattern of muscle involvement that develops later, with the onset of a muscular dystrophy primarily affecting proximal or distal muscles.
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Affiliation(s)
- L V Anderson
- Neurobiology Department, University Medical School, Framlington Place, Newcastle upon Tyne NE2 4HH, UK.
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