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Nascimento A, Bruels CC, Donkervoort S, Foley AR, Codina A, Milisenda JC, Estrella EA, Li C, Pijuan J, Draper I, Hu Y, Stafki SA, Pais LS, Ganesh VS, O'Donnell-Luria A, Syeda SB, Carrera-García L, Expósito-Escudero J, Yubero D, Martorell L, Pinal-Fernandez I, Lidov HGW, Mammen AL, Grau-Junyent JM, Ortez C, Palau F, Ghosh PS, Darras BT, Jou C, Kunkel LM, Hoenicka J, Bönnemann CG, Kang PB, Natera-de Benito D. Variants in DTNA cause a mild, dominantly inherited muscular dystrophy. Acta Neuropathol 2023; 145:479-496. [PMID: 36799992 PMCID: PMC10923638 DOI: 10.1007/s00401-023-02551-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Revised: 02/10/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023]
Abstract
DTNA encodes α-dystrobrevin, a component of the macromolecular dystrophin-glycoprotein complex (DGC) that binds to dystrophin/utrophin and α-syntrophin. Mice lacking α-dystrobrevin have a muscular dystrophy phenotype, but variants in DTNA have not previously been associated with human skeletal muscle disease. We present 12 individuals from four unrelated families with two different monoallelic DTNA variants affecting the coiled-coil domain of α-dystrobrevin. The five affected individuals from family A harbor a c.1585G > A; p.Glu529Lys variant, while the recurrent c.1567_1587del; p.Gln523_Glu529del DTNA variant was identified in the other three families (family B: four affected individuals, family C: one affected individual, and family D: two affected individuals). Myalgia and exercise intolerance, with variable ages of onset, were reported in 10 of 12 affected individuals. Proximal lower limb weakness with onset in the first decade of life was noted in three individuals. Persistent elevations of serum creatine kinase (CK) levels were detected in 11 of 12 affected individuals, 1 of whom had an episode of rhabdomyolysis at 20 years of age. Autism spectrum disorder or learning disabilities were reported in four individuals with the c.1567_1587 deletion. Muscle biopsies in eight affected individuals showed mixed myopathic and dystrophic findings, characterized by fiber size variability, internalized nuclei, and slightly increased extracellular connective tissue and inflammation. Immunofluorescence analysis of biopsies from five affected individuals showed reduced α-dystrobrevin immunoreactivity and variably reduced immunoreactivity of other DGC proteins: dystrophin, α, β, δ and γ-sarcoglycans, and α and β-dystroglycans. The DTNA deletion disrupted an interaction between α-dystrobrevin and syntrophin. Specific variants in the coiled-coil domain of DTNA cause skeletal muscle disease with variable penetrance. Affected individuals show a spectrum of clinical manifestations, with severity ranging from hyperCKemia, myalgias, and exercise intolerance to childhood-onset proximal muscle weakness. Our findings expand the molecular etiologies of both muscular dystrophy and paucisymptomatic hyperCKemia, to now include monoallelic DTNA variants as a novel cause of skeletal muscle disease in humans.
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Affiliation(s)
- Andres Nascimento
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, Barcelona, Spain
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Christine C Bruels
- Department of Neurology, Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, 420 Delaware Street SE, MMC 295, Minneapolis, MN, 55455, USA
| | - Sandra Donkervoort
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - A Reghan Foley
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Anna Codina
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Jose C Milisenda
- Department of Internal Medicine, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain
| | - Elicia A Estrella
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Chengcheng Li
- Division of Pediatric Neurology, University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Jordi Pijuan
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Laboratory of Neurogenetics and Molecular Medicine-IPER, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Isabelle Draper
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA, 02111, USA
| | - Ying Hu
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Seth A Stafki
- Department of Neurology, Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, 420 Delaware Street SE, MMC 295, Minneapolis, MN, 55455, USA
| | - Lynn S Pais
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics, Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Vijay S Ganesh
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics, Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
- Department of Neurology, Brigham and Women's Hospital, Boston, MA, USA
| | - Anne O'Donnell-Luria
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
- Program in Medical and Population Genetics, Center for Mendelian Genomics, Broad Institute of MIT and Harvard, Cambridge, MA, USA
- Analytic and Translational Genetics Unit and Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Safoora B Syeda
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Laura Carrera-García
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, Barcelona, Spain
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Jessica Expósito-Escudero
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, Barcelona, Spain
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Delia Yubero
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Department of Genetic and Molecular Medicine-IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Loreto Martorell
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Department of Genetic and Molecular Medicine-IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Iago Pinal-Fernandez
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Hart G W Lidov
- Department of Pathology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Andrew L Mammen
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD, USA
- Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Josep M Grau-Junyent
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Department of Internal Medicine, Hospital Clinic of Barcelona, University of Barcelona, Barcelona, Spain
| | - Carlos Ortez
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, Barcelona, Spain
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
| | - Francesc Palau
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Laboratory of Neurogenetics and Molecular Medicine-IPER, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- Department of Genetic and Molecular Medicine-IPER, Hospital Sant Joan de Déu and Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Partha S Ghosh
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Basil T Darras
- Department of Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Cristina Jou
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Department of Pathology, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA, USA
| | - Janet Hoenicka
- Center for Biomedical Research Network on Rare Diseases (CIBERER), ISCIII, Madrid, Spain
- Laboratory of Neurogenetics and Molecular Medicine-IPER, Institut de Recerca Sant Joan de Déu, Barcelona, Spain
| | - Carsten G Bönnemann
- Neuromuscular and Neurogenetic Disorders of Childhood Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
| | - Peter B Kang
- Department of Neurology, Paul and Sheila Wellstone Muscular Dystrophy Center, University of Minnesota Medical School, 420 Delaware Street SE, MMC 295, Minneapolis, MN, 55455, USA.
- Institute for Translational Neuroscience, University of Minnesota, Minneapolis, MN, USA.
| | - Daniel Natera-de Benito
- Neuromuscular Unit, Department of Neurology, Hospital Sant Joan de Déu, Passeig Sant Joan de Déu 2, Esplugues de Llobregat, Barcelona, Spain.
- Applied Research in Neuromuscular Diseases, Institut de Recerca Sant Joan de Déu, Barcelona, Spain.
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Humanizing the mdx mouse model of DMD: the long and the short of it. NPJ Regen Med 2018; 3:4. [PMID: 29479480 PMCID: PMC5816599 DOI: 10.1038/s41536-018-0045-4] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/19/2017] [Accepted: 01/04/2018] [Indexed: 12/26/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a common fatal heritable myopathy, with cardiorespiratory failure occurring by the third decade of life. There is no specific treatment for DMD cardiomyopathy, in large part due to a lack of understanding of the mechanisms underlying the cardiac failure. Mdx mice, which have the same dystrophin mutation as human patients, are of limited use, as they do not develop early dilated cardiomyopathy as seen in patients. Here we summarize the usefulness of the various commonly used DMD mouse models, highlight a model with shortened telomeres like humans, and identify directions that warrant further investigation.
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Zlotina A, Nikulina T, Yany N, Moiseeva O, Pervunina T, Grekhov E, Kostareva A. Ring chromosome 18 in combination with 18q12.1 (DTNA) interstitial microdeletion in a patient with multiple congenital defects. Mol Cytogenet 2016; 9:18. [PMID: 26893613 PMCID: PMC4758088 DOI: 10.1186/s13039-016-0229-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 02/10/2016] [Indexed: 11/20/2022] Open
Abstract
Background Ring chromosome 18 [r(18)] syndrome represents a relatively rare condition with a complex clinical picture including multiple congenital dysmorphia and varying degrees of mental retardation. The condition is cytogenetically characterized by a complete or mosaic form of ring chromosome 18, with ring formation being usually accompanied by the partial loss of both chromosomal arms. Here we observed a 20-year-old male patient who along with the features typical for r(18) carriers additionally manifested a severe congenital subaortic stenosis. To define the genetic basis of such a compound phenotype, standard cytogenetic and high-resolution molecular-cytogenetic analysis of the patient was performed. Case presentation Standard chromosome analysis of cultured lymphocytes confirmed 46, XY, r(18) karyotype. Array-based comparative genomic hybridization (array-CGH) allowed to define precisely the breakpoints of 18p and 18q terminal deletions, thus identifying the hemizygosity extent, and to reveal an additional duplication adjoining the breakpoint of the 18p deletion. Apart from the terminal imbalances, we found an interstitial microdeletion of 442 kb in size (18q12.1) that encompassed DTNA gene encoding α-dystrobrevin, a member of dystrophin-associated glycoprotein complex. While limited data on the role of DTNA missense mutations in pathogenesis of human cardiac abnormalities exist, a microdeletion corresponding to whole DTNA sequence and not involving other genes has not been earlier described. Conclusions A detailed molecular-cytogenetic characterization of the patient with multiple congenital abnormalities enabled to unravel a combination of genetic defects, namely, a ring chromosome 18 with terminal imbalances and DTNA whole-gene deletion. We suggest that such combination could contribute to the complex phenotype. The findings obtained allow to extend the knowledge of the role of DTNA haploinsufficiency in congenital heart malformation, though further comprehensive functional studies are required. Electronic supplementary material The online version of this article (doi:10.1186/s13039-016-0229-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anna Zlotina
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia ; Institute of translational Medicine, ITMO University, Saint-Petersburg, 199034 Russia ; Cytology and Histology Department, Saint Petersburg State University, Saint-Petersburg, 199034 Russia
| | - Tatiana Nikulina
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia
| | - Natalia Yany
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia
| | - Olga Moiseeva
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia
| | - Tatiana Pervunina
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia
| | - Eugeny Grekhov
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia
| | - Anna Kostareva
- Almazov Federal Medical Research Centre, Saint-Petersburg, 197341 Russia ; Department of Women's and Children's Health, Center for Molecular Medicine, Karolinska Institute, Stockholm, 17176 Sweden
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Contribution of oxidative stress to pathology in diaphragm and limb muscles with Duchenne muscular dystrophy. J Muscle Res Cell Motil 2012; 34:1-13. [DOI: 10.1007/s10974-012-9330-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Accepted: 10/18/2012] [Indexed: 11/27/2022]
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Dystrobrevin controls neurotransmitter release and muscle Ca(2+) transients by localizing BK channels in Caenorhabditis elegans. J Neurosci 2012; 31:17338-47. [PMID: 22131396 DOI: 10.1523/jneurosci.3638-11.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Dystrobrevin is a major component of a dystrophin-associated protein complex. It is widely expressed in mammalian tissues, including the nervous system, in which it is localized to the presynaptic nerve terminal with unknown function. In a genetic screen for suppressors of a lethargic phenotype caused by a gain-of-function isoform of SLO-1 in Caenorhabditis elegans, we isolated multiple loss-of-function (lf) mutants of the dystrobrevin gene dyb-1.dyb-1(lf) phenocopied slo-1(lf), causing increased neurotransmitter release at the neuromuscular junction, increased frequency of Ca(2+) transients in body-wall muscle, and abnormal locomotion behavior. Neuron- and muscle-specific rescue experiments suggest that DYB-1 is required for SLO-1 function in both neurons and muscle cells. DYB-1 colocalized with SLO-1 at presynaptic sites in neurons and dense body regions in muscle cells, and dyb-1(lf) caused SLO-1 mislocalization in both types of cells without altering SLO-1 protein level. The neuronal phenotypes of dyb-1(lf) were partially rescued by mouse α-dystrobrevin-1. These observations revealed novel functions of the BK channel in regulating muscle Ca(2+) transients and of dystrobrevin in controlling neurotransmitter release and muscle Ca(2+) transients by localizing the BK channel.
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Davisson MT, Bronson RT, Tadenev ALD, Motley WW, Krishnaswamy A, Seburn KL, Burgess RW. A spontaneous mutation in contactin 1 in the mouse. PLoS One 2011; 6:e29538. [PMID: 22242131 PMCID: PMC3248457 DOI: 10.1371/journal.pone.0029538] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2011] [Accepted: 11/30/2011] [Indexed: 01/06/2023] Open
Abstract
Mutations in the gene encoding the immunoglobulin-superfamily member cell adhesion molecule contactin1 (CNTN1) cause lethal congenital myopathy in human patients and neurodevelopmental phenotypes in knockout mice. Whether the mutant mice provide an accurate model of the human disease is unclear; resolving this will require additional functional tests of the neuromuscular system and examination of Cntn1 mutations on different genetic backgrounds that may influence the phenotype. Toward these ends, we have analyzed a new, spontaneous mutation in the mouse Cntn1 gene that arose in a BALB/c genetic background. The overt phenotype is very similar to the knockout of Cntn1, with affected animals having reduced body weight, a failure to thrive, locomotor abnormalities, and a lifespan of 2-3 weeks. Mice homozygous for the new allele have CNTN1 protein undetectable by western blotting, suggesting that it is a null or very severe hypomorph. In an analysis of neuromuscular function, neuromuscular junctions had normal morphology, consistent with previous studies in knockout mice, and the muscles were able to generate appropriate force when normalized for their reduced size in late stage animals. Therefore, the Cntn1 mutant mice do not show evidence for a myopathy, but instead the phenotype is likely to be caused by dysfunction in the nervous system. Given the similarity of CNTN1 to other Ig-superfamily proteins such as DSCAMs, we also characterized the expression and localization of Cntn1 in the retinas of mutant mice for developmental defects. Despite widespread expression, no anomalies in retinal anatomy were detected histologically or using a battery of cell-type specific antibodies. We therefore conclude that the phenotype of the Cntn1 mice arises from dysfunction in the brain, spinal cord or peripheral nervous system, and is similar in either a BALB/c or B6;129;Black Swiss background, raising a possible discordance between the mouse and human phenotypes resulting from Cntn1 mutations.
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Affiliation(s)
- Muriel T Davisson
- The Jackson Laboratory, Bar Harbor, Maine, United States of America.
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Nakagaki WR, Camilli JA. Bone tissue and muscle dystrophin deficiency in mdx mice. Joint Bone Spine 2011; 79:129-33. [PMID: 22079415 DOI: 10.1016/j.jbspin.2011.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 08/08/2011] [Indexed: 01/06/2023]
Abstract
Duchenne muscular dystrophy is a neuromuscular disease caused by the lack of dystrophin that affects skeletal muscles, causing degeneration of muscle fibers and replacing them with fibrous and adipose tissue, events that gradually lead to functional loss. Patients with Duchenne muscular dystrophy have shown that bones become more fragile with age and with advancement of the disease. Muscle weakness and reduced mobility have been suggested to be the factors that promote bone deterioration. However, it seems that this does not occur in mdx mice. It has been identified in mdx mice the existence of a factor related or not to the lack of dystrophin that also participates in the impairment of bone quality. Mdx mice also exhibit muscle degeneration, but unlike human, it is compensated by muscle regeneration. In consequence, there is an increase in the muscle mass, but not necessarily of muscle contractile strength. The accommodation of this increased muscle mass promotes bone formation at specific sites, such as at tendo-osseous junctions. In addition, the inflammatory response to muscle injury may be responsible for the increase in angiogenesis and regeneration observed in mdx mice, inducing the release of cytokines and chemokines that play an important role in the recruitment of leukocytes and macrophages. Then, mdx mice may possess compensatory mechanisms in bone in response to a genetic defect.
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Affiliation(s)
- Wilson Romero Nakagaki
- Department of Anatomy, Cell Biology and Physiology and Biophysics, Institute of Biology, State University of Campinas (UNICAMP), Campinas, SP, Brazil
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Lawler JM. Exacerbation of pathology by oxidative stress in respiratory and locomotor muscles with Duchenne muscular dystrophy. J Physiol 2011; 589:2161-70. [PMID: 21486793 PMCID: PMC3098695 DOI: 10.1113/jphysiol.2011.207456] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Accepted: 03/02/2011] [Indexed: 12/15/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most devastating type of muscular dystrophy, leading to progressive weakness of respiratory (e.g. diaphragm) and locomotor muscles (e.g. gastrocnemius). DMD is caused by X-linked defects in the gene that encodes for dystrophin, a key scaffolding protein of the dystroglycan complex (DCG) within the sarcolemmal cytoskeleton. As a result of a compromised dystroglycan complex, mechanical integrity is impaired and important signalling proteins (e.g. nNOS, caveolin-3) and pathways are disrupted. Disruption of the dystroglycan complex leads to high susceptibility to injury with repeated, eccentric contractions as well as inflammation, resulting in significant damage and necrosis. Chronic damage and repair cycling leads to fibrosis and weakness. While the link between inflammation with damage and weakness in the DMD diaphragm is unresolved, elevated oxidative stress may contribute to damage, weakness and possibly fibrosis. While utilization of non-specific antioxidant interventions has yielded inconsistent results, recent data suggest that NAD(P)H oxidase could play a pivotal role in elevating oxidative stress via integrated changes in caveolin-3 and stretch-activated channels (SACs). Oxidative stress may act as an amplifier, exacerbating disruption of the dystroglycan complex, upregulation of the inflammatory transcription factor NF-B, and thus functional impairment of force-generating capacity.
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Affiliation(s)
- John M Lawler
- Department of Health and Kinesiology, Texas A&M University, College Station, TX 77843-4243, USA.
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Nakamori M, Takahashi MP. The role of α-dystrobrevin in striated muscle. Int J Mol Sci 2011; 12:1660-71. [PMID: 21673914 PMCID: PMC3111625 DOI: 10.3390/ijms12031660] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 01/29/2011] [Accepted: 02/23/2011] [Indexed: 12/29/2022] Open
Abstract
Muscular dystrophies are a group of diseases that primarily affect striated muscle and are characterized by the progressive loss of muscle strength and integrity. Major forms of muscular dystrophies are caused by the abnormalities of the dystrophin glycoprotein complex (DGC) that plays crucial roles as a structural unit and scaffolds for signaling molecules at the sarcolemma. α-Dystrobrevin is a component of the DGC and directly associates with dystrophin. α-Dystrobrevin also binds to intermediate filaments as well as syntrophin, a modular adaptor protein thought to be involved in signaling. Although no muscular dystrophy has been associated within mutations of the α-dystrobrevin gene, emerging findings suggest potential significance of α-dystrobrevin in striated muscle. This review addresses the functional role of α-dystrobrevin in muscle as well as its possible implication for muscular dystrophy.
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Affiliation(s)
- Masayuki Nakamori
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2, D-4, Yamadaoka, Suita, Osaka 565-0871, Japan; E-Mail:
- Department of Neurology, University of Rochester Medical Center, 601 Elmwood Avenue, Box 645 URMC, Rochester, NY 14642, USA
| | - Masanori P. Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, 2-2, D-4, Yamadaoka, Suita, Osaka 565-0871, Japan; E-Mail:
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +81-6-6879-3571; Fax: +81-6-6879-3579
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De Arcangelis V, Serra F, Cogoni C, Vivarelli E, Monaco L, Naro F. β1-syntrophin modulation by miR-222 in mdx mice. PLoS One 2010; 5:e12098. [PMID: 20856896 PMCID: PMC2938373 DOI: 10.1371/journal.pone.0012098] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Accepted: 07/18/2010] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND In mdx mice, the absence of dystrophin leads to the deficiency of other components of the dystrophin-glycoprotein complex (DAPC), making skeletal muscle fibers more susceptible to necrosis. The mechanisms involved in the disappearance of the DAPC are not completely understood. The muscles of mdx mice express normal amounts of mRNA for the DAPC components, thus suggesting post-transcriptional regulation. METHODOLOGY/PRINCIPAL FINDINGS We investigated the hypothesis that DAPC reduction could be associated with the microRNA system. Among the possible microRNAs (miRs) found to be upregulated in the skeletal muscle tissue of mdx compared to wt mice, we demonstrated that miR-222 specifically binds to the 3'-UTR of β1-syntrophin and participates in the downregulation of β1-syntrophin. In addition, we documented an altered regulation of the 3'-UTR of β1-syntrophin in muscle tissue from dystrophic mice. CONCLUSION/SIGNIFICANCE These results show the importance of the microRNA system in the regulation of DAPC components in dystrophic muscle, and suggest a potential role of miRs in the pathophysiology of dystrophy.
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Affiliation(s)
| | - Filippo Serra
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
| | - Carlo Cogoni
- Department of Cellular Biotechnology and Ematology, University Sapienza, Rome, Italy
| | - Elisabetta Vivarelli
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
| | - Lucia Monaco
- Department of Physiology and Pharmacology, University Sapienza, Rome, Italy
| | - Fabio Naro
- Department of Histology and Medical Embryology, University Sapienza, Rome, Italy
- IIM, Pavia, Italy
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Finsterer J. Cardiogenetics, neurogenetics, and pathogenetics of left ventricular hypertrabeculation/noncompaction. Pediatr Cardiol 2009; 30:659-81. [PMID: 19184181 DOI: 10.1007/s00246-008-9359-0] [Citation(s) in RCA: 164] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2008] [Accepted: 11/15/2008] [Indexed: 01/28/2023]
Abstract
BACKGROUND Left ventricular hypertrabeculation (LVHT), also known as noncompaction or spongy myocardium, is a cardiac abnormality of unknown etiology and pathogenesis frequently associated with genetic cardiac and noncardiac disorders, particularly genetic neuromuscular disease. This study aimed to review the current knowledge about the genetic or pathogenetic background of LVHT. METHODS A literature review of all human studies dealing with the association of LVHT with genetic cardiac and noncardiac disorders, particularly neuromuscular disorders, was conducted. RESULTS Most frequently, LVHT is associated with mitochondrial disorders (mtDNA, nDNA mutations), Barth syndrome (G4.5, TAZ mutations), hypertrophic cardiomyopathy (MYH7, ACTC mutations), zaspopathy (ZASP/LDB3 mutations), myotonic dystrophy 1 (DMPK mutations), and dystrobrevinopathy (DTNA mutations). More rarely, LVHT is associated with mutations in the DMD, SCNA5, MYBPC3, FNLA1, PTPN11, LMNA, ZNF9, AMPD1, PMP22, TNNT2, fibrillin2, SHP2, MMACHC, LMX1B, HCCS, or NR0B1 genes. Additionally, LVHT occurs with a number of chromosomal disorders, polymorphisms, and not yet identified genes, as well in a familial context. The broad heterogeneity of LVHT's genetic background suggests that the uniform morphology of LVHT not only is attributable to embryonic noncompaction but also may result from induction of hypertrabeculation as a compensatory reaction of an impaired myocardium. CONCLUSIONS Most frequently, LVHT is associated with mutations in genes causing muscle or cardiac disease, or with chromosomal disorders. These associations require comprehensive cardiac, neurologic, and cytogenetic investigations.
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Affiliation(s)
- Josef Finsterer
- Krankenanstalt Rudolfstiftung, Postfach 20, 1180 Vienna, Austria, Europe.
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12
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Reed UC. Congenital muscular dystrophy. Part I: a review of phenotypical and diagnostic aspects. ARQUIVOS DE NEURO-PSIQUIATRIA 2009; 67:144-68. [DOI: 10.1590/s0004-282x2009000100038] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2008] [Accepted: 12/17/2008] [Indexed: 12/30/2022]
Abstract
The congenital muscular dystrophies (CMDs) are a group of genetically and clinically heterogeneous hereditary myopathies with preferentially autosomal recessive inheritance, that are characterized by congenital hypotonia, delayed motor development and early onset of progressive muscle weakness associated with dystrophic pattern on muscle biopsy. The clinical course is broadly variable and can comprise the involvement of the brain and eyes. From 1994, a great development in the knowledge of the molecular basis has occurred and the classification of CMDs has to be continuously up dated. We initially present the main clinical and diagnostic data concerning the CMDs related to changes in the complex dystrophin-associated glycoproteins-extracellular matrix: CMD with merosin deficiency (CMD1A), collagen VI related CMDs (Ullrich CMD and Bethlem myopathy), CMDs with abnormal glycosylation of alpha-dystroglycan (Fukuyama CMD, Muscle-eye-brain disease, Walker-Warburg syndrome, CMD1C, CMD1D), and the much rarer CMD with integrin deficiency. Finally, we present other forms of CMDs not related with the dystrophin/glycoproteins/extracellular matrix complex (rigid spine syndrome, CMD1B, CMD with lamin A/C deficiency), and some apparently specific clinical forms not yet associated with a known molecular mechanism. The second part of this review concerning the pathogenesis and therapeutic perspectives of the different subtypes of CMD will be described in a next number.
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13
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Kemp MW, Edwards B, Burgess M, Clarke WT, Nicholson G, Parry DAD, Davies KE. Syncoilin isoform organization and differential expression in murine striated muscle. J Struct Biol 2008; 165:196-203. [PMID: 19070665 DOI: 10.1016/j.jsb.2008.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2008] [Revised: 10/30/2008] [Accepted: 11/06/2008] [Indexed: 12/01/2022]
Abstract
Syncoilin is a 64kDa intermediate filament (IF) protein expressed in myocytes at the sarcolemma, perinucleus, myotendenous and neuromuscular junctions. Here we present a revised domain projection and structural analysis for the original isoform (sync-1) and introduce two novel syncoilin isoforms (sync-2 and sync-3) generated by exon splicing. On the basis of consensus identity we propose that syncoilin be reclassified as a type III IF protein. All three syncoilin isoforms lack a L1 domain, a significant departure from standard IF rod domain projections that is likely to impact significantly on their biological function. Our analyses indicate that syncoilin is unlikely to form classical intermediate filament structures by itself, and that the significant difference in C-terminal structure between the three isoforms indicates that they may play divergent roles in myocytes. We show that despite lacking an apparent structural role in striated muscle, syncoilin isoforms are differentially and strongly upregulated in response to cardiotoxin induced regeneration and denervation induced atrophy in the C57BL/6 mouse, possibly suggesting an atypical role for syncoilin in muscle.
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Affiliation(s)
- Matthew W Kemp
- MRC Functional Genomics Unit, Department of Anatomy, Physiology and Genetics, University of Oxford, South Parks Road, Oxford OX13QX, UK
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14
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Compton AG, Albrecht DE, Seto JT, Cooper ST, Ilkovski B, Jones KJ, Challis D, Mowat D, Ranscht B, Bahlo M, Froehner SC, North KN. Mutations in contactin-1, a neural adhesion and neuromuscular junction protein, cause a familial form of lethal congenital myopathy. Am J Hum Genet 2008; 83:714-24. [PMID: 19026398 DOI: 10.1016/j.ajhg.2008.10.022] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 10/16/2008] [Accepted: 10/29/2008] [Indexed: 01/06/2023] Open
Abstract
We have previously reported a group of patients with congenital onset weakness associated with a deficiency of members of the syntrophin-alpha-dystrobrevin subcomplex and have demonstrated that loss of syntrophin and dystrobrevin from the sarcolemma of skeletal muscle can also be associated with denervation. Here, we have further studied four individuals from a consanguineous Egyptian family with a lethal congenital myopathy inherited in an autosomal-recessive fashion and characterized by a secondary loss of beta2-syntrophin and alpha-dystrobrevin from the muscle sarcolemma, central nervous system involvement, and fetal akinesia. We performed homozygosity mapping and candidate gene analysis and identified a mutation that segregates with disease within CNTN1, the gene encoding for the neural immunoglobulin family adhesion molecule, contactin-1. Contactin-1 transcripts were markedly decreased on gene-expression arrays of muscle from affected family members compared to controls. We demonstrate that contactin-1 is expressed at the neuromuscular junction (NMJ) in mice and man in addition to the previously documented expression in the central and peripheral nervous system. In patients with secondary dystroglycanopathies, we show that contactin-1 is abnormally localized to the sarcolemma instead of exclusively at the NMJ. The cntn1 null mouse presents with ataxia, progressive muscle weakness, and postnatal lethality, similar to the affected members in this family. We propose that loss of contactin-1 from the NMJ impairs communication or adhesion between nerve and muscle resulting in the severe myopathic phenotype. This disorder is part of the continuum in the clinical spectrum of congenital myopathies and congenital myasthenic syndromes.
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Affiliation(s)
- Alison G Compton
- Institute for Neuromuscular Research, The Children's Hospital at Westmead, NSW, Australia
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15
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Peat RA, Gécz J, Fallon JR, Tarpey PS, Smith R, Futreal A, Stratton MR, Lamandé SR, Yang N, North KN. Exclusion of biglycan mutations in a cohort of patients with neuromuscular disorders. Neuromuscul Disord 2008; 18:606-9. [PMID: 18602826 PMCID: PMC2873833 DOI: 10.1016/j.nmd.2008.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2008] [Revised: 04/09/2008] [Accepted: 05/28/2008] [Indexed: 10/21/2022]
Abstract
Biglycan has been considered a good candidate for neuromuscular disease based on direct interactions with collagen VI and alpha-dystroglycan, both of which are linked with congenital muscular dystrophy (CMD). We screened 83 patients with CMD and other neuromuscular disorders and six controls for mutations and variations in the biglycan sequence. We identified a number of novel sequence variations. After family analysis and control screening we found that none of these polymorphisms were disease-causing mutations. Thus mutations in biglycan are not a common cause of neuromuscular disorders in our cohort.
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Affiliation(s)
- Rachel A Peat
- Institute for Neuromuscular Research, The Children's Hospital at Westmead, Sydney, Australia
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16
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McCullagh KJA, Edwards B, Kemp MW, Giles LC, Burgess M, Davies KE. Analysis of skeletal muscle function in the C57BL6/SV129 syncoilin knockout mouse. Mamm Genome 2008; 19:339-51. [PMID: 18594912 PMCID: PMC2515546 DOI: 10.1007/s00335-008-9120-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Accepted: 05/28/2008] [Indexed: 11/28/2022]
Abstract
Syncoilin is a 64-kDa intermediate filament protein expressed in skeletal muscle and enriched at the perinucleus, sarcolemma, and myotendinous and neuromuscular junctions. Due to its pattern of cellular localization and binding partners, syncoilin is an ideal candidate to be both an important structural component of myocytes and a potential mediator of inherited myopathies. Here we present a report of a knockout mouse model for syncoilin and the results of an investigation into the effect of a syncoilin null state on striated muscle function in 6–8-week-old mice. An analysis of proteins known to associate with syncoilin showed that ablation of syncoilin had no effect on absolute expression or spatial localization of desmin or alpha dystrobrevin. Our syncoilin-null animal exhibited no differences in cardiotoxin-induced muscle regeneration, voluntary wheel running, or enforced treadmill exercise capacity, relative to wild-type controls. Finally, a mechanical investigation of isolated soleus and extensor digitorum longus indicated a potential differential reduction in muscle strength and resilience. We are the first to present data identifying an increased susceptibility to muscle damage in response to an extended forced exercise regime in syncoilin-deficient muscle. This study establishes a second viable syncoilin knockout model and highlights the importance of further investigations to determine the role of syncoilin in skeletal muscle.
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Affiliation(s)
- Karl J A McCullagh
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
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17
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MacArthur DG, Seto JT, Raftery JM, Quinlan KG, Huttley GA, Hook JW, Lemckert FA, Kee AJ, Edwards MR, Berman Y, Hardeman EC, Gunning PW, Easteal S, Yang N, North KN. Loss of ACTN3 gene function alters mouse muscle metabolism and shows evidence of positive selection in humans. Nat Genet 2007; 39:1261-5. [PMID: 17828264 DOI: 10.1038/ng2122] [Citation(s) in RCA: 203] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2007] [Accepted: 08/07/2007] [Indexed: 11/09/2022]
Abstract
More than a billion humans worldwide are predicted to be completely deficient in the fast skeletal muscle fiber protein alpha-actinin-3 owing to homozygosity for a premature stop codon polymorphism, R577X, in the ACTN3 gene. The R577X polymorphism is associated with elite athlete status and human muscle performance, suggesting that alpha-actinin-3 deficiency influences the function of fast muscle fibers. Here we show that loss of alpha-actinin-3 expression in a knockout mouse model results in a shift in muscle metabolism toward the more efficient aerobic pathway and an increase in intrinsic endurance performance. In addition, we demonstrate that the genomic region surrounding the 577X null allele shows low levels of genetic variation and recombination in individuals of European and East Asian descent, consistent with strong, recent positive selection. We propose that the 577X allele has been positively selected in some human populations owing to its effect on skeletal muscle metabolism.
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Affiliation(s)
- Daniel G MacArthur
- Institute for Neuromuscular Research, Children's Hospital at Westmead, Sydney, New South Wales 2145, Australia
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18
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Rees MLJ, Lien CF, Górecki DC. Dystrobrevins in muscle and non-muscle tissues. Neuromuscul Disord 2007; 17:123-34. [PMID: 17251025 DOI: 10.1016/j.nmd.2006.11.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2006] [Revised: 10/26/2006] [Accepted: 11/20/2006] [Indexed: 01/23/2023]
Abstract
The alpha- and beta-dystrobrevins belong to the family of dystrophin-related and dystrophin-associated proteins. As constituents of the dystrophin-associated protein complex, alpha-dystrobrevin was believed to have a role predominantly in muscles and beta-dystrobrevin in non-muscle tissues. Recent reports described novel localisations and molecular characteristics of alpha-dystrobrevin isoforms in non-muscle tissues (developing and adult). While single and double knockout studies have revealed distinct functions of dystrobrevin in some tissues, these also suggested a strong compensatory mechanism, where dystrobrevins displaying overlapping tissue expression pattern and structure/function similarity can substitute each other. No human disease has been unequivocally associated within mutations of dystrobrevin genes. However, some significant exceptions to these overlapping expression patterns, mainly in the brain, suggest that dystrobrevin mutations might underlie some specific motor, behavioural or cognitive defects. Dystrobrevin binding partner DTNBP1 (dysbindin) is a probable susceptibility gene for schizophrenia and bipolar affective disorder in some populations. As dysbindin abnormality is linked to Hermansky-Pudlak syndrome, dystrobrevins and/or their binding partners may also be required for proper function of other non-muscle tissues.
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Affiliation(s)
- Melissa L J Rees
- Department of Molecular Medicine, Institute of Biomedical and Biomolecular Sciences, School of Pharmacy and Biomedical Sciences, University of Portsmouth, UK
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19
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Alessi A, Bragg AD, Percival JM, Yoo J, Albrecht DE, Froehner SC, Adams ME. gamma-Syntrophin scaffolding is spatially and functionally distinct from that of the alpha/beta syntrophins. Exp Cell Res 2006; 312:3084-95. [PMID: 16857187 DOI: 10.1016/j.yexcr.2006.06.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2006] [Revised: 06/06/2006] [Accepted: 06/07/2006] [Indexed: 10/24/2022]
Abstract
The syntrophins are a family of scaffolding proteins with multiple protein interaction domains that link signaling proteins to dystrophin family members. Each of the three most characterized syntrophins (alpha, beta1, beta2) contains a PDZ domain that binds a unique set of signaling proteins including kinases, ion and water channels, and neuronal nitric oxide synthase (nNOS). The PDZ domains of the gamma-syntrophins do not bind nNOS. In vitro pull-down assays show that the gamma-syntrophins can bind dystrophin but have unique preferences for the syntrophin binding sites of dystrophin family members. Despite their ability to bind dystrophin in vitro, neither gamma-syntrophin isoform co-localizes with dystrophin in skeletal muscle. Furthermore, gamma-syntrophins do not co-purify with dystrophin isolated from mouse tissue. These data suggest that the interaction of gamma-syntrophin with dystrophin is transient and potentially subject to regulatory mechanisms. gamma1-Syntrophin is highly expressed in brain and is specifically localized in hippocampal pyramidal neurons, Purkinje neurons in cerebellum, and cortical neurons. gamma2-Syntrophin is expressed in many tissues including skeletal muscle where it is found only in the subsynaptic space beneath the neuromuscular junction. In both neurons and muscle, gamma-syntrophin isoforms localize to the endoplasmic reticulum where they may form a scaffold for signaling and trafficking.
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Affiliation(s)
- Amy Alessi
- Department of Physiology and Biophysics, University of Washington, 1959 Pacific ST NE, Seattle, WA 98195-7290, USA
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20
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Finsterer J, Stöllberger C, Blazek G. Neuromuscular implications in left ventricular hypertrabeculation/noncompaction. Int J Cardiol 2006; 110:288-300. [PMID: 16364474 DOI: 10.1016/j.ijcard.2005.10.028] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 09/22/2005] [Accepted: 10/15/2005] [Indexed: 12/31/2022]
Abstract
This review focuses on recent advances in the association between left ventricular hypertrabeculation/noncompaction (LVHT), a form of unclassified cardiomyopathy, and neuromuscular disorders (NMD). So far, LVHT has been found in single patients with dystrophinopathy, dystrobrevinopathy, laminopathy, zaspopathy, myotonic dystrophy, infantile glycogenosis type II (Pompe's disease), myoadenylate-deaminase deficiency, mitochondriopathy, Barth syndrome, Friedreich ataxia, and Charcot-Marie-Tooth disease. Most frequently LVHT is found in patients with Barth syndrome and mitochondrial disorders. The prevalence of LVHT in NMD patients is not known. On the contrary, NMD can be detected in up to four fifths of the patients with LVHT. Because LVHT is associated with an increased risk of rhythm abnormalities and heart failure, it is essential to detect LVHT as soon as possible. Because of adequate therapeutic options, all patients with NMD should undergo a comprehensive cardiological examination as soon as their neurological diagnosis is established. In reverse, all patients with LVHT should undergo a comprehensive neurological investigation following the detection of LVHT.
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21
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Compton AG, Cooper ST, Hill PM, Yang N, Froehner SC, North KN. The syntrophin-dystrobrevin subcomplex in human neuromuscular disorders. J Neuropathol Exp Neurol 2005; 64:350-61. [PMID: 15835271 DOI: 10.1093/jnen/64.4.350] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The syntrophins and alpha-dystrobrevin form a subcomplex with dystrophin at the skeletal muscle membrane, and are also highly concentrated at the neuromuscular synapse. Here we demonstrate that the different syntrophins and alpha-dystrobrevin isoforms have distinct expression patterns during human skeletal muscle development, and are differentially affected by loss of dystrophin anchorage and denervation in human neuromuscular disease. During normal fetal development, and in Duchenne muscular dystrophy and denervation disorders, alpha1-syntrophin and alpha-dystrobrevin are absent or markedly reduced at the sarcolemmal membrane. beta1-Syntrophin is the predominant syntrophin isoform expressed at the muscle membrane during development, and it undergoes upregulation in response to loss of alpha1-syntrophin in Duchenne muscular dystrophy and in denervation. Upregulation of beta1-syntrophin in neuromuscular disorders is associated with re-expression of the fetal nicotinic acetylcholine receptor gamma-subunit, cardiac actin, and neonatal myosin, suggesting reversion of muscle fibers to an immature phenotype. We show that denervation specifically affects expression of the syntrophin-dystrobrevin subcomplex and does not affect levels or localization of other members of the dystrophin-associated protein complex. Our results confirm that dystrophin is required for anchorage of the syntrophin-dystrobrevin subcomplex and suggest that expression of the syntrophin-dystrobrevin complex may be independently regulated through neuromuscular transmission.
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Affiliation(s)
- Alison G Compton
- Institute for Neuromuscular Research, Children's Hospital at Westmead, NSW, Australia
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22
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Anderson JE, Wozniak AC. Satellite cell activation on fibers: modeling events in vivo — an invited review. Can J Physiol Pharmacol 2004; 82:300-10. [PMID: 15213729 DOI: 10.1139/y04-020] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Knowledge of the events underlying satellite cell activation and the counterpart maintenance of quiescence is essential for planning therapies that will promote the growth and regeneration of skeletal muscle in healthy, disease and aging. By modeling those events of satellite cell activation in studies of single muscle fibers or muscles in culture, the roles of mechanical stretching and nitric oxide are becoming understood. Recent studies demonstrated that stretch-induced activation is very rapid and exhibits some features of satellite cell heterogeneity. As well, gene expression studies showed that expression of the c-met receptor gene rises rapidly after stretching muscles in culture compared to those without stretch. This change in gene expression during activation, and the maintenance of quiescence in both normal and dystrophic muscles are dependent on NO, as they are blocked by inhibition of nitric oxide synthase (NOS). Mechanical, contractile activity is the defining feature of muscle function. Therefore, ongoing studies of stretch effects in satellite cell activation and quiescence in quiescent fiber and muscle cultures provides appropriate models by which to explore the regulatory steps in muscle in vivo under many conditions related to disease, repair, rehabilitation, growth and the prevention or treatment of atrophy.Key words: regeneration, stretch, myofiber culture, muscular dystrophy, quiescence.
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Affiliation(s)
- Judy E Anderson
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Canada.
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