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Bouchard C, Tremblay JP. Portrait of Dysferlinopathy: Diagnosis and Development of Therapy. J Clin Med 2023; 12:6011. [PMID: 37762951 PMCID: PMC10531777 DOI: 10.3390/jcm12186011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 09/13/2023] [Accepted: 09/14/2023] [Indexed: 09/29/2023] Open
Abstract
Dysferlinopathy is a disease caused by a dysferlin deficiency due to mutations in the DYSF gene. Dysferlin is a membrane protein in the sarcolemma and is involved in different functions, such as membrane repair and vesicle fusion, T-tubule development and maintenance, Ca2+ signalling, and the regulation of various molecules. Miyoshi Myopathy type 1 (MMD1) and Limb-Girdle Muscular Dystrophy 2B/R2 (LGMD2B/LGMDR2) are two possible clinical presentations, yet the same mutations can cause both presentations in the same family. They are therefore grouped under the name dysferlinopathy. Onset is typically during the teenage years or young adulthood and is characterized by a loss of Achilles tendon reflexes and difficulty in standing on tiptoes or climbing stairs, followed by a slow progressive loss of strength in limb muscles. The MRI pattern of patient muscles and their biopsies show various fibre sizes, necrotic and regenerative fibres, and fat and connective tissue accumulation. Recent tools were developed for diagnosis and research, especially to evaluate the evolution of the patient condition and to prevent misdiagnosis caused by similarities with polymyositis and Charcot-Marie-Tooth disease. The specific characteristic of dysferlinopathy is dysferlin deficiency. Recently, mouse models with patient mutations were developed to study genetic approaches to treat dysferlinopathy. The research fields for dysferlinopathy therapy include symptomatic treatments, as well as antisense-mediated exon skipping, myoblast transplantation, and gene editing.
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Affiliation(s)
- Camille Bouchard
- Département de Médecine Moléculaire, Université Laval, Québec, QC G1V 0A6, Canada;
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Québec, QC G1E 6W2, Canada
| | - Jacques P. Tremblay
- Département de Médecine Moléculaire, Université Laval, Québec, QC G1V 0A6, Canada;
- Centre de Recherche du Centre Hospitalier Universitaire de Québec, Québec, QC G1E 6W2, Canada
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2
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Bouchard C, Tremblay JP. Limb-Girdle Muscular Dystrophies Classification and Therapies. J Clin Med 2023; 12:4769. [PMID: 37510884 PMCID: PMC10381329 DOI: 10.3390/jcm12144769] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 07/05/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
Limb-girdle muscular dystrophies (LGMDs) are caused by mutations in multiple genes. This review article presents 39 genes associated with LGMDs. Some forms are inherited in a dominant fashion, while for others this occurs recessively. The classification of LGMDs has evolved through time. Lately, to be considered an LGMD, the mutation has to cause a predominant proximal muscle weakness and must be found in two or more unrelated families. This article also presents therapies for LGMDs, examining both available treatments and those in development. For now, only symptomatic treatments are available for patients. The goal is now to solve the problem at the root of LGMDs instead of treating each symptom individually. In the last decade, multiple other potential treatments were developed and studied, such as stem-cell transplantation, exon skipping, gene delivery, RNAi, and gene editing.
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Affiliation(s)
- Camille Bouchard
- Departement de Médecine Moléculaire, Université Laval, Quebec, QC G1V 0A6, Canada
- Centre de Recherche du Centre Hospitalier Universitaire de Quebec, Quebec, QC G1E 6W2, Canada
| | - Jacques P Tremblay
- Departement de Médecine Moléculaire, Université Laval, Quebec, QC G1V 0A6, Canada
- Centre de Recherche du Centre Hospitalier Universitaire de Quebec, Quebec, QC G1E 6W2, Canada
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3
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Warner WC. Orthopedic Surgery in Neuromuscular Disorders. Neuromuscul Disord 2022. [DOI: 10.1016/b978-0-323-71317-7.00009-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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4
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Taheri F, Taghizadeh E, Pour MJR, Rostami D, Renani PG, Rastgar-Moghadam A, Hayat SMG. Limb-girdle Muscular Dystrophy and Therapy: Insights into Cell and Gene-based Approaches. Curr Gene Ther 2020; 19:386-394. [PMID: 32067617 DOI: 10.2174/1566523220666200218113526] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 01/11/2020] [Accepted: 02/04/2020] [Indexed: 12/17/2022]
Abstract
The Limb-Girdle Muscular Dystrophies (LGMD) are genetically heterogeneous disorders, responsible for muscle wasting and severe form of dystrophies. Despite the critical developments in the insight and information of pathomechanisms of limb-girdle muscular dystrophy, any definitive treatments do not exist, and current strategies are only based on the improvement of the signs of disorder and to enhance the life quality without resolving an underlying cause. There is a crucial relationship between pharmacological therapy and different consequences; therefore, other treatment strategies will be required. New approaches, such as gene replacement, gene transfer, exon skipping, siRNA knockdown, and anti-myostatin therapy, which can target specific cellular or molecular mechanism of LGMD, could be a promising avenue for the treatment. Recently, genome engineering strategies with a focus on molecular tools such as CRISPR-Cas9 are used to different types of neuromuscular disorders and show the highest potential for clinical translation of these therapies. Thus, recent advancements and challenges in the field will be reviewed in this paper.
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Affiliation(s)
- Forough Taheri
- Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Eskandar Taghizadeh
- Cellular and Molecular Research Center, Yasuj University of Medical Sciences, Yasuj, Iran.,Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Mohammad J R Pour
- Department of Biology, Faculty of Sciences, Mashhad-Branch, Islamic Azad University, Mashhad, Iran
| | - Daryoush Rostami
- Department of School Allied, Zabol University of Medical Sciences, Zabol, Iran
| | - Pedram G Renani
- Shahrekord Branch, Islamic Azad University, Shahrekord, Iran
| | - Azam Rastgar-Moghadam
- Department of Genetics, Tehran Medical Sciences Branch, Islamic Azad University, Tehran, Iran
| | - Seyed M G Hayat
- Department of Medical Genetics, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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5
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Demonbreun AR, Wyatt EJ, Fallon KS, Oosterbaan CC, Page PG, Hadhazy M, Quattrocelli M, Barefield DY, McNally EM. A gene-edited mouse model of limb-girdle muscular dystrophy 2C for testing exon skipping. Dis Model Mech 2019; 13:dmm040832. [PMID: 31582396 PMCID: PMC6906631 DOI: 10.1242/dmm.040832] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Accepted: 09/23/2019] [Indexed: 12/21/2022] Open
Abstract
Limb-girdle muscular dystrophy type 2C is caused by autosomal recessive mutations in the γ-sarcoglycan (SGCG) gene. The most common SGCG mutation is a single nucleotide deletion from a stretch of five thymine residues in SGCG exon 6 (521ΔT). This founder mutation disrupts the transcript reading frame, abolishing protein expression. An antisense oligonucleotide exon-skipping method to reframe the human 521ΔT transcript requires skipping four exons to generate a functional, internally truncated protein. In vivo evaluation of this multi-exon skipping, antisense-mediated therapy requires a genetically appropriate mouse model. The human and mouse γ-sarcoglycan genes are highly homologous in sequence and gene structure, including the exon 6 region harboring the founder mutation. Herein, we describe a new mouse model of this form of limb-girdle muscular dystrophy generated using CRISPR/Cas9-mediated gene editing to introduce a single thymine deletion in murine exon 6, recreating the 521ΔT point mutation in Sgcg These mice express the 521ΔT transcript, lack γ-sarcoglycan protein and exhibit a severe dystrophic phenotype. Phenotypic characterization demonstrated reduced muscle mass, increased sarcolemmal leak and fragility, and decreased muscle function, consistent with the human pathological findings. Furthermore, we showed that intramuscular administration of a murine-specific multiple exon-directed antisense oligonucleotide cocktail effectively corrected the 521ΔT reading frame. These data demonstrate a molecularly and pathologically suitable model for in vivo testing of a multi-exon skipping strategy to advance preclinical development of this genetic correction approach.
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Affiliation(s)
- Alexis R Demonbreun
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
- Department of Pharmacology, Northwestern University, Chicago, IL 60611, USA
| | - Eugene J Wyatt
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Katherine S Fallon
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Claire C Oosterbaan
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Patrick G Page
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Michele Hadhazy
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Mattia Quattrocelli
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - David Y Barefield
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University, Chicago, IL 60611, USA
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Abstract
There has been an ever-expanding list of the Limb-Girdle Muscular Dystrophies (LGMD). There are currently 8 subtypes of autosomal dominant (AD) and 26 subtypes of autosomal recessive (AR) LGMD. Despite continued research efforts to conquer this group of genetic neuromuscular disease, patients continue to be treated symptomatically with the aim of prevention or addressing complications. Mouse models have been helpful in clarifying disease pathogenesis as well as strategizing pathways for treatment. Discoveries in translational research as well as molecular therapeutic approaches have kept clinicians optimistic that more promising clinical trials will lead the way to finding the cure for these devastating disorders. It is well known that the challenge for these rare diseases is the ability to assemble adequate numbers of patients for a clinically meaningful trial, but current efforts in developing patient registries have been encouraging. Natural history studies will be essential in establishing and interpreting the appropriate outcome measures for clinical trials. Nevertheless, animal studies continue to be key in providing proof of concept that will be necessary in moving research along. This review will briefly discuss each type of LGMD, highlighting their distinguishing features, then focus on research efforts that have been published in the literature for the past few years, many of which are still in the preclinical trial stage.
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Affiliation(s)
- Mary Lynn Chu
- Department of Neurology, New York University School of Medicine, New York, New York, 10016, USA.
- New York University Langone Orthopedic Hospital, 301 East 17th Street, New York, New York, 10003, USA.
| | - Ellen Moran
- Division of Clinical Genetics, Center for Children, Hassenfeld Children's Hospital at New York University Langone, New York University Langone Orthopedic Hospital, 301 East 17th Street, New York, New York, 10003, USA
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Wyatt EJ, Demonbreun AR, Kim EY, Puckelwartz MJ, Vo AH, Dellefave-Castillo LM, Gao QQ, Vainzof M, Pavanello RCM, Zatz M, McNally EM. Efficient exon skipping of SGCG mutations mediated by phosphorodiamidate morpholino oligomers. JCI Insight 2018; 3:99357. [PMID: 29720576 DOI: 10.1172/jci.insight.99357] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 04/05/2018] [Indexed: 12/15/2022] Open
Abstract
Exon skipping uses chemically modified antisense oligonucleotides to modulate RNA splicing. Therapeutically, exon skipping can bypass mutations and restore reading frame disruption by generating internally truncated, functional proteins to rescue the loss of native gene expression. Limb-girdle muscular dystrophy type 2C is caused by autosomal recessive mutations in the SGCG gene, which encodes the dystrophin-associated protein γ-sarcoglycan. The most common SGCG mutations disrupt the transcript reading frame abrogating γ-sarcoglycan protein expression. In order to treat most SGCG gene mutations, it is necessary to skip 4 exons in order to restore the SGCG transcript reading frame, creating an internally truncated protein referred to as Mini-Gamma. Using direct reprogramming of human cells with MyoD, myogenic cells were tested with 2 antisense oligonucleotide chemistries, 2'-O-methyl phosphorothioate oligonucleotides and vivo-phosphorodiamidate morpholino oligomers, to induce exon skipping. Treatment with vivo-phosphorodiamidate morpholino oligomers demonstrated efficient skipping of the targeted exons and corrected the mutant reading frame, resulting in the expression of a functional Mini-Gamma protein. Antisense-induced exon skipping of SGCG occurred in normal cells and those with multiple distinct SGCG mutations, including the most common 521ΔT mutation. These findings demonstrate a multiexon-skipping strategy applicable to the majority of limb-girdle muscular dystrophy 2C patients.
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Affiliation(s)
- Eugene J Wyatt
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Alexis R Demonbreun
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Ellis Y Kim
- Committee on Molecular Medicine and Molecular Pathogenesis and
| | - Megan J Puckelwartz
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Andy H Vo
- Committee on Developmental Biology and Regenerative Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Lisa M Dellefave-Castillo
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Quan Q Gao
- Division of Hematology/Oncology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Mariz Vainzof
- Human Genome and Stem-Cell Center, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Rita C M Pavanello
- Human Genome and Stem-Cell Center, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Mayana Zatz
- Human Genome and Stem-Cell Center, Institute of Biosciences, University of São Paulo, São Paulo, Brazil
| | - Elizabeth M McNally
- Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Where do we stand in trial readiness for autosomal recessive limb girdle muscular dystrophies? Neuromuscul Disord 2015; 26:111-25. [PMID: 26810373 DOI: 10.1016/j.nmd.2015.11.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 11/27/2015] [Accepted: 11/29/2015] [Indexed: 12/20/2022]
Abstract
Autosomal recessive limb girdle muscular dystrophies (LGMD2) are a group of genetically heterogeneous diseases that are typically characterised by progressive weakness and wasting of the shoulder and pelvic girdle muscles. Many of the more than 20 different conditions show overlapping clinical features with other forms of muscular dystrophy, congenital, myofibrillar or even distal myopathies and also with acquired muscle diseases. Although individually extremely rare, all types of LGMD2 together form an important differential diagnostic group among neuromuscular diseases. Despite improved diagnostics and pathomechanistic insight, a curative therapy is currently lacking for any of these diseases. Medical care consists of the symptomatic treatment of complications, aiming to improve life expectancy and quality of life. Besides well characterised pre-clinical tools like animal models and cell culture assays, the determinants of successful drug development programmes for rare diseases include a good understanding of the phenotype and natural history of the disease, the existence of clinically relevant outcome measures, guidance on care standards, up to date patient registries, and, ideally, biomarkers that can help assess disease severity or drug response. Strong patient organisations driving research and successful partnerships between academia, advocacy, industry and regulatory authorities can also help accelerate the elaboration of clinical trials. All these determinants constitute aspects of translational research efforts and influence patient access to therapies. Here we review the current status of determinants of successful drug development programmes for LGMD2, and the challenges of translating promising therapeutic strategies into effective and accessible treatments for patients.
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Aho AC, Hultsjö S, Hjelm K. Young adults' experiences of living with recessive limb-girdle muscular dystrophy from a salutogenic orientation: an interview study. Disabil Rehabil 2015; 37:2083-91. [PMID: 25582030 DOI: 10.3109/09638288.2014.998782] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE To describe young adults' experiences of living with recessive limb-girdle muscular dystrophy (LGMD2) from a salutogenic orientation. METHODS A qualitative explorative interview study, including 14 participants aged 20-30 years, was performed focusing on comprehensibility, manageability and meaningfulness in daily life. Content analysis was used for data analysis. RESULT Living with LGMD2 not only implies learning to live with the disease and the variations between good and bad periods but also means trying to make sense of a progressive disease that brings uncertainty about future health, by striving to make the best of the situation. Disease progression involves practical and mental struggle, trying to maintain control over one's life despite vanished physical functions that require continual adjustments to the body. Restrictions in a double sense were described, not only due to the disease but also due to poor comprehension of the disease in society. Lack of knowledge about LGMD2 among professionals often results in having to fight for the support needed. CONCLUSION In order to manage daily life, it is important to be seen and understood as an individual in contacts with professionals and in society in general, to have informal social support and meaningful activities as well as access to personal assistance if necessary. IMPLICATIONS FOR REHABILITATION Recessive limb-girdle muscular dystrophy (LGMD2) is a group of progressive disorders, which manifest in physical and psychological consequences for the individual. According to the salutogenic orientation, people need to find life comprehensible, manageable and meaningful, i.e. to achieve a sense of coherence (SOC), but living with LGMD2 may recurrently challenge the individual's SOC. Through the holistic view of the individual's situation that the salutogenic orientation provides, professionals may support the individual to strengthen SOC and thereby facilitate the movement towards health.
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Affiliation(s)
- Anna Carin Aho
- a Department of Health and Caring Sciences , Linnaeus University , Växjö , Sweden
| | - Sally Hultsjö
- b Psychiatric Clinic, County Hospital , Ryhov, Jönköping , Sweden , and
| | - Katarina Hjelm
- c Department of Social and Welfare Studies , Campus Norrköping, Linköping University , Linköping , Sweden
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Rosales XQ, al-Dahhak R, Tsao CY. Childhood onset of limb-girdle muscular dystrophy. Pediatr Neurol 2012; 46:13-23. [PMID: 22196486 DOI: 10.1016/j.pediatrneurol.2011.08.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Accepted: 08/25/2011] [Indexed: 01/16/2023]
Abstract
Limb-girdle muscular dystrophies comprise a rare heterogeneous group of genetic muscular dystrophies, involving 15 autosomal recessive subtypes and seven autosomal dominant subtypes. Autosomal recessive dystrophy is far more common than autosomal dominant dystrophy. Typical clinical features include progressive limb muscle weakness and atrophy (proximal greater than distal), varying from very mild to severe. Significant overlap of clinical phenotypes, with genetic and clinical heterogeneity, constitutes the rule for this group of diseases. Muscle biopsies are useful for histopathologic and immunolabeling studies, and DNA analysis is the gold standard to establish the specific form of muscular dystrophy. A definitive diagnosis among various subtypes is challenging, and the data presented here provide neuromuscular clinicians with additional information to help attain that goal.
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Affiliation(s)
- Xiomara Q Rosales
- Neuromuscular Division, Department of Pediatrics, Nationwide Children's Hospital, Columbus, Ohio, USA
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11
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Guglieri M, Bushby K. Limb–Girdle Dystrophies. Neuromuscul Disord 2011. [DOI: 10.1002/9781119973331.ch8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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12
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Rüegg MA, Glass DJ. Molecular mechanisms and treatment options for muscle wasting diseases. Annu Rev Pharmacol Toxicol 2011; 51:373-95. [PMID: 20936944 DOI: 10.1146/annurev-pharmtox-010510-100537] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Loss of muscle mass can be the consequence of pathological changes, as observed in muscular dystrophies; or it can be secondary to cachexia-inducing diseases that cause muscle atrophy, such as cancer, heart disease, or chronic obstructive pulmonary disease; or it can be a consequence of aging or simple disuse. Although muscular dystrophies are rare, muscle loss affects millions of people worldwide. We discuss the molecular mechanisms involved in muscular dystrophy and in muscle atrophy and present current strategies aimed at ameliorating these diseases. Finally, we discuss whether lessons learned from studying muscular dystrophies will also be helpful for halting muscle loss secondary to nondystrophic diseases and whether strategies to halt muscle atrophy have potential for the treatment of muscular dystrophies.
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Fiaccavento R, Carotenuto F, Vecchini A, Binaglia L, Forte G, Capucci E, Maccari AM, Minieri M, Di Nardo P. An omega-3 fatty acid-enriched diet prevents skeletal muscle lesions in a hamster model of dystrophy. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 177:2176-84. [PMID: 20829440 DOI: 10.2353/ajpath.2010.100174] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Currently, despite well-known mutational causes, a universal treatment for neuromuscular disorders is still lacking, and current therapeutic efforts are mainly restricted to symptomatic treatments. In the present study, δ-sarcoglycan-null dystrophic hamsters were fed a diet enriched in flaxseed-derived ω3 α-linolenic fatty acid from weaning until death. α-linolenic fatty acid precluded the dystrophic degeneration of muscle morphology and function. In fact, in dystrophic animals fed flaxseed-derived α-linolenic fatty acid, the histological appearance of the muscular tissue was improved, the proliferation of interstitial cells was decreased, and the myogenic differentiation originated new myocytes to repair the injured muscle. In addition, muscle myofibers were larger and cell membrane integrity was preserved, as witnessed by the correct localization of α-, β-, and γ-sarcoglycans and α-dystroglycan. Furthermore, the cytoplasmic accumulation of both β-catenin and caveolin-3 was abolished in dystrophic hamster muscle fed α-linolenic fatty acid versus control animals fed standard diet, while α-myosin heavy chain was expressed at nearly physiological levels. These findings, obtained by dietary intervention only, introduce a novel concept that provides evidence that the modulation of the plasmalemma lipid profile could represent an efficacious strategy to ameliorate human muscular dystrophy.
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Affiliation(s)
- Roberta Fiaccavento
- Laboratorio di Cardiologia Molecolare e Cellulare, Dipartimento di Medicina Interna, Università di Roma Tor Vergata, Via Montpellier, 1, 00133 Roma, Italy
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14
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Abstract
Muscular dystrophies are individually rare genetic disorders that cause much chronic disability, affecting young children and adults. In the past 20 years, more than 30 genetic types of muscular dystrophy have been defined. During this time, precise diagnosis, genetic counselling, and medical management have improved. These advances in medical practice have occurred while definitive therapies based on an improved knowledge of disease pathogenesis are awaited. A wide range of therapeutic options have been tested in animal models, and some are being tested in clinical trials. Various therapeutic targets are being investigated, from personalised medicines targeting specific mutations and drugs targeting cellular pathways to gene-based and cell-based therapies.
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Affiliation(s)
- Kate Bushby
- Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, UK.
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Abstract
Sarcoglycanopathies are a group of autosomal recessive muscle-wasting disorders caused by genetic defects in one of four cell membrane glycoproteins, alpha-, beta-, gamma- or delta-sarcoglycan. These four sarcoglycans form a subcomplex that is closely linked to the major dystrophin-associated protein complex, which is essential for membrane integrity during muscle contraction and provides a scaffold for important signalling molecules. Proper assembly, trafficking and targeting of the sarcoglycan complex is of vital importance, and mutations that severely perturb tetramer formation and localisation result in sarcoglycanopathy. Gene defects in one sarcoglycan cause the absence or reduced concentration of the other subunits. Most genetic defects generate mutated proteins that are degraded through the cell's quality control system; however, in many cases, conformational modifications do not affect the function of the protein, yet it is recognised as misfolded and prematurely degraded. Recent evidence shows that misfolded sarcoglycans could be rescued to the cell membrane by assisting their maturation along the ER secretory pathway. This review summarises the etiopathogenesis of sarcoglycanopathies and highlights the quality control machinery as a potential pharmacological target for therapy of these genetic disorders.
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Affiliation(s)
- Dorianna Sandonà
- Department of Biomedical Sciences, University of Padova, 35121
Padova, Italy
| | - Romeo Betto
- C.N.R. Institute of Neuroscience, Neuromuscular Biology and
Physiopathology, 35121 Padova, Italy
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Trollet C, Athanasopoulos T, Popplewell L, Malerba A, Dickson G. Gene therapy for muscular dystrophy: current progress and future prospects. Expert Opin Biol Ther 2009; 9:849-66. [DOI: 10.1517/14712590903029164] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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