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Peysson A, Zariohi N, Gendrel M, Chambert-Loir A, Frébault N, Cheynet E, Andrini O, Boulin T. Wnt-Ror-Dvl signalling and the dystrophin complex organize planar-polarized membrane compartments in C. elegans muscles. Nat Commun 2024; 15:4935. [PMID: 38858388 PMCID: PMC11164867 DOI: 10.1038/s41467-024-49154-8] [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: 10/24/2023] [Accepted: 05/24/2024] [Indexed: 06/12/2024] Open
Abstract
Cell polarity mechanisms allow the formation of specialized membrane domains with unique protein compositions, signalling properties, and functional characteristics. By analyzing the localization of potassium channels and proteins belonging to the dystrophin-associated protein complex, we reveal the existence of distinct planar-polarized membrane compartments at the surface of C. elegans muscle cells. We find that muscle polarity is controlled by a non-canonical Wnt signalling cascade involving the ligand EGL-20/Wnt, the receptor CAM-1/Ror, and the intracellular effector DSH-1/Dishevelled. Interestingly, classical planar cell polarity proteins are not required for this process. Using time-resolved protein degradation, we demonstrate that -while it is essentially in place by the end of embryogenesis- muscle polarity is a dynamic state, requiring continued presence of DSH-1 throughout post-embryonic life. Our results reveal the unsuspected complexity of the C. elegans muscle membrane and establish a genetically tractable model system to study cellular polarity and membrane compartmentalization in vivo.
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Affiliation(s)
- Alice Peysson
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Noura Zariohi
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Marie Gendrel
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, Université Paris Sciences et Lettres Research University, Paris, 75005, France
| | - Amandine Chambert-Loir
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Noémie Frébault
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Elise Cheynet
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Olga Andrini
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France
| | - Thomas Boulin
- Université Claude Bernard Lyon 1, CNRS UMR 5284, INSERM U1314, MeLiS, Lyon, 69008, France.
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2
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Molecular and cellular basis of genetically inherited skeletal muscle disorders. Nat Rev Mol Cell Biol 2021; 22:713-732. [PMID: 34257452 PMCID: PMC9686310 DOI: 10.1038/s41580-021-00389-z] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/04/2021] [Indexed: 02/06/2023]
Abstract
Neuromuscular disorders comprise a diverse group of human inborn diseases that arise from defects in the structure and/or function of the muscle tissue - encompassing the muscle cells (myofibres) themselves and their extracellular matrix - or muscle fibre innervation. Since the identification in 1987 of the first genetic lesion associated with a neuromuscular disorder - mutations in dystrophin as an underlying cause of Duchenne muscular dystrophy - the field has made tremendous progress in understanding the genetic basis of these diseases, with pathogenic variants in more than 500 genes now identified as underlying causes of neuromuscular disorders. The subset of neuromuscular disorders that affect skeletal muscle are referred to as myopathies or muscular dystrophies, and are due to variants in genes encoding muscle proteins. Many of these proteins provide structural stability to the myofibres or function in regulating sarcolemmal integrity, whereas others are involved in protein turnover, intracellular trafficking, calcium handling and electrical excitability - processes that ensure myofibre resistance to stress and their primary activity in muscle contraction. In this Review, we discuss how defects in muscle proteins give rise to muscle dysfunction, and ultimately to disease, with a focus on pathologies that are most common, best understood and that provide the most insight into muscle biology.
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3
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Rugowska A, Starosta A, Konieczny P. Epigenetic modifications in muscle regeneration and progression of Duchenne muscular dystrophy. Clin Epigenetics 2021; 13:13. [PMID: 33468200 PMCID: PMC7814631 DOI: 10.1186/s13148-021-01001-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 12/14/2020] [Indexed: 02/08/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a multisystemic disorder that affects 1:5000 boys. The severity of the phenotype varies dependent on the mutation site in the DMD gene and the resultant dystrophin expression profile. In skeletal muscle, dystrophin loss is associated with the disintegration of myofibers and their ineffective regeneration due to defective expansion and differentiation of the muscle stem cell pool. Some of these phenotypic alterations stem from the dystrophin absence-mediated serine-threonine protein kinase 2 (MARK2) misplacement/downregulation in activated muscle stem (satellite) cells and neuronal nitric oxide synthase loss in cells committed to myogenesis. Here, we trace changes in DNA methylation, histone modifications, and expression of regulatory noncoding RNAs during muscle regeneration, from the stage of satellite cells to myofibers. Furthermore, we describe the abrogation of these epigenetic regulatory processes due to changes in signal transduction in DMD and point to therapeutic treatments increasing the regenerative potential of diseased muscles based on this acquired knowledge.
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Affiliation(s)
- Anna Rugowska
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznan, Poland
| | - Alicja Starosta
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznan, Poland
| | - Patryk Konieczny
- Institute of Human Biology and Evolution, Faculty of Biology, Adam Mickiewicz University, ul. Uniwersytetu Poznańskiego 6, 61-614, Poznan, Poland.
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4
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Nelson DM, Fasbender EK, Jakubiak MC, Lindsay A, Lowe DA, Ervasti JM. Rapid, redox-mediated mechanical susceptibility of the cortical microtubule lattice in skeletal muscle. Redox Biol 2020; 37:101730. [PMID: 33002761 PMCID: PMC7527753 DOI: 10.1016/j.redox.2020.101730] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 09/12/2020] [Accepted: 09/12/2020] [Indexed: 01/25/2023] Open
Abstract
The highly ordered cortical microtubule lattice of skeletal muscle is disorganized in dystrophin-deficient mdx mice. Implicated mechanisms include loss of dystrophin binding, altered α-tubulin posttranslational modification, expression of a β-tubulin involved in regeneration, and reactive oxygen species (ROS). Here we show that the transverse microtubules in mdx muscle expressing miniaturized dystrophins are rapidly lost after eccentric contraction. Analysis of mdx lines expressing different dystrophin constructs demonstrate that spectrin-like repeats R4-15 and R20-23 were required for mechanically stable microtubules. Microtubule loss was prevented by the non-specific antioxidant N-acetylcysteine while inhibition of NADPH oxidase 2 had only a partial effect, suggesting that ROS from multiple sources mediate the rapid loss of transverse microtubules after eccentric contraction. Finally, ablation of α-dystrobrevin, β- or γ-cytoplasmic actin phenocopied the transverse microtubule instability of miniaturized dystrophins. Our data demonstrate that multiple dystrophin domains, α-dystrobrevin and cytoplasmic actins are necessary for mechanically stable microtubules.
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Affiliation(s)
- D'anna M Nelson
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA
| | - Elizabeth K Fasbender
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Margurite C Jakubiak
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Angus Lindsay
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA; Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Dawn A Lowe
- Department of Rehabilitation Medicine, University of Minnesota, Minneapolis, MN, USA
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, Minneapolis, MN, USA.
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5
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Visualizing Biological Membrane Organization and Dynamics. J Mol Biol 2019; 431:1889-1919. [DOI: 10.1016/j.jmb.2019.02.018] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 02/02/2019] [Accepted: 02/13/2019] [Indexed: 11/22/2022]
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Interleukin 37 reverses the metabolic cost of inflammation, increases oxidative respiration, and improves exercise tolerance. Proc Natl Acad Sci U S A 2017; 114:2313-2318. [PMID: 28193888 DOI: 10.1073/pnas.1619011114] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
IL-1 family member interleukin 37 (IL-37) has broad antiinflammatory properties and functions as a natural suppressor of innate inflammation. In this study, we demonstrate that treatment with recombinant human IL-37 reverses the decrease in exercise performance observed during systemic inflammation. This effect was associated with a decrease in the levels of plasma and muscle cytokines, comparable in extent to that obtained upon IL-1 receptor blockade. Exogenous administration of IL-37 to healthy mice, not subjected to an inflammatory challenge, also improved exercise performance by 82% compared with vehicle-treated mice (P = 0.01). Treatment with eight daily doses of IL-37 resulted in a further 326% increase in endurance running time compared with the performance level of mice receiving vehicle (P = 0.001). These properties required the engagement of the IL-1 decoy receptor 8 (IL-1R8) and the activation of AMP-activated protein kinase (AMPK), because both inhibition of AMPK and IL-1R8 deficiency abrogated the positive effects of IL-37 on exercise performance. Mechanistically, treatment with IL-37 induced marked metabolic changes with higher levels of muscle AMPK, greater rates of oxygen consumption, and increased oxidative phosphorylation. Metabolomic analyses of plasma and muscles of mice treated with IL-37 revealed an increase in AMP/ATP ratio, reduced levels of proinflammatory mediator succinate and oxidative stress-related metabolites, as well as changes in amino acid and purine metabolism. These effects of IL-37 to limit the metabolic costs of chronic inflammation and to foster exercise tolerance provide a rationale for therapeutic use of IL-37 in the treatment of inflammation-mediated fatigue.
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Zhao J, Kodippili K, Yue Y, Hakim CH, Wasala L, Pan X, Zhang K, Yang NN, Duan D, Lai Y. Dystrophin contains multiple independent membrane-binding domains. Hum Mol Genet 2016; 25:3647-3653. [PMID: 27378693 DOI: 10.1093/hmg/ddw210] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2016] [Revised: 06/14/2016] [Accepted: 06/27/2016] [Indexed: 01/09/2023] Open
Abstract
Dystrophin is a large sub-sarcolemmal protein. Its absence leads to Duchenne muscular dystrophy (DMD). Binding to the sarcolemma is essential for dystrophin to protect muscle from contraction-induced injury. It has long been thought that membrane binding of dystrophin depends on its cysteine-rich (CR) domain. Here, we provide in vivo evidence suggesting that dystrophin contains three additional membrane-binding domains including spectrin-like repeats (R)1-3, R10-12 and C-terminus (CT). To systematically study dystrophin membrane binding, we split full-length dystrophin into ten fragments and examined subcellular localizations of each fragment by adeno-associated virus-mediated gene transfer. In skeletal muscle, R1-3, CR domain and CT were exclusively localized at the sarcolemma. R10-12 showed both cytosolic and sarcolemmal localization. Importantly, the CR-independent membrane binding was conserved in murine and canine muscles. A critical function of the CR-mediated membrane interaction is the assembly of the dystrophin-associated glycoprotein complex (DGC). While R1-3 and R10-12 did not restore the DGC, surprisingly, CT alone was sufficient to establish the DGC at the sarcolemma. Additional studies suggest that R1-3 and CT also bind to the sarcolemma in the heart, though relatively weak. Taken together, our study provides the first conclusive in vivo evidence that dystrophin contains multiple independent membrane-binding domains. These structurally and functionally distinctive membrane-binding domains provide a molecular framework for dystrophin to function as a shock absorber and signaling hub. Our results not only shed critical light on dystrophin biology and DMD pathogenesis, but also provide a foundation for rationally engineering minimized dystrophins for DMD gene therapy.
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Affiliation(s)
- Junling Zhao
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Kasun Kodippili
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Yongping Yue
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Chady H Hakim
- Department of Molecular Microbiology and Immunology, School of Medicine.,National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Lakmini Wasala
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Xiufang Pan
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Keqing Zhang
- Department of Molecular Microbiology and Immunology, School of Medicine
| | - Nora N Yang
- National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine .,Department of Neurology, School of Medicine.,Department of Bioengineering.,Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO, USA
| | - Yi Lai
- Department of Molecular Microbiology and Immunology, School of Medicine
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8
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Whitmore C, Morgan J. What do mouse models of muscular dystrophy tell us about the DAPC and its components? Int J Exp Pathol 2014; 95:365-77. [PMID: 25270874 PMCID: PMC4285463 DOI: 10.1111/iep.12095] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 08/16/2014] [Indexed: 12/17/2022] Open
Abstract
There are over 30 mouse models with mutations or inactivations in the dystrophin-associated protein complex. This complex is thought to play a crucial role in the functioning of muscle, as both a shock absorber and signalling centre, although its role in the pathogenesis of muscular dystrophy is not fully understood. The first mouse model of muscular dystrophy to be identified with a mutation in a component of the dystrophin-associated complex (dystrophin) was the mdx mouse in 1984. Here, we evaluate the key characteristics of the mdx in comparison with other mouse mutants with inactivations in DAPC components, along with key modifiers of the disease phenotype. By discussing the differences between the individual phenotypes, we show that the functioning of the DAPC and consequently its role in the pathogenesis is more complicated than perhaps currently appreciated.
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Affiliation(s)
- Charlotte Whitmore
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neurosciences Programme, Institute of Child Health, University College LondonLondon, UK
| | - Jennifer Morgan
- Dubowitz Neuromuscular Centre, Molecular Neurosciences Section, Developmental Neurosciences Programme, Institute of Child Health, University College LondonLondon, UK
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9
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Townsend D. Finding the sweet spot: assembly and glycosylation of the dystrophin-associated glycoprotein complex. Anat Rec (Hoboken) 2014; 297:1694-705. [PMID: 25125182 PMCID: PMC4135523 DOI: 10.1002/ar.22974] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/27/2014] [Indexed: 01/12/2023]
Abstract
The dystrophin-associated glycoprotein complex (DGC) is a collection of glycoproteins that are essential for the normal function of striated muscle and many other tissues. Recent genetic studies have implicated the components of this complex in over a dozen forms of muscular dystrophy. Furthermore, disruption of the DGC has been implicated in many forms of acquired disease. This review aims to summarize the current state of knowledge regarding the processing and assembly of dystrophin-associated proteins with a focus primarily on the dystroglycan heterodimer and the sarcoglycan complex. These proteins form the transmembrane portion of the DGC and undergo a complex multi-step processing with proteolytic cleavage, differential assembly, and both N- and O-glycosylation. The enzymes responsible for this processing and a model describing the sequence and subcellular localization of these events are discussed.
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Affiliation(s)
- Dewayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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10
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Strakova J, Dean JD, Sharpe KM, Meyers TA, Odom GL, Townsend D. Dystrobrevin increases dystrophin's binding to the dystrophin-glycoprotein complex and provides protection during cardiac stress. J Mol Cell Cardiol 2014; 76:106-15. [PMID: 25158611 DOI: 10.1016/j.yjmcc.2014.08.013] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 08/14/2014] [Accepted: 08/16/2014] [Indexed: 01/05/2023]
Abstract
Duchenne muscular dystrophy is a fatal progressive disease of both cardiac and skeletal muscle resulting from the mutations in the DMD gene and loss of the protein dystrophin. Alpha-dystrobrevin (α-DB) tightly associates with dystrophin but the significance of this interaction within cardiac myocytes is poorly understood. In the current study, the functional role of α-DB in cardiomyocytes and its implications for dystrophin function are examined. Cardiac stress testing demonstrated significant heart disease in α-DB null (adbn(-/-)) mice, which displayed mortality and lesion sizes that were equivalent to those seen in dystrophin-deficient mdx mice. Despite normal expression and subcellular localization of dystrophin in the adbn(-/-) heart, there is a significant decrease in the strength of dystrophin's interaction with the membrane-bound dystrophin-associated glycoprotein complex (DGC). A similar weakening of the dystrophin-membrane interface was observed in mice lacking the sarcoglycan complex. Cardiomyocytes from adbn(-/-) mice were smaller and responded less to adrenergic receptor induced hypertrophy. The basal decrease in size could not be attributed to aberrant Akt activation. In addition, the organization of the microtubule network was significantly altered in adbn(-/-) cardiac myocytes, while the total expression of tubulin was unchanged in adbn(-/-) hearts. These studies demonstrate that α-DB is a multifunctional protein that increases dystrophin's binding to the dystrophin-glycoprotein complex, and is critical for the full functionality of dystrophin.
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Affiliation(s)
- Jana Strakova
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Jon D Dean
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Katharine M Sharpe
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Tatyana A Meyers
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA
| | - Guy L Odom
- Department of Neurology, University of Washington, Seattle, WA, USA
| | - DeWayne Townsend
- Department of Integrative Biology and Physiology, University of Minnesota, Minneapolis, MN, USA.
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11
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Joe MK, Kee C, Tomarev SI. Myocilin interacts with syntrophins and is member of dystrophin-associated protein complex. J Biol Chem 2012; 287:13216-27. [PMID: 22371502 DOI: 10.1074/jbc.m111.224063] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Genetic studies have linked myocilin to open angle glaucoma, but the functions of the protein in the eye and other tissues have remained elusive. The purpose of this investigation was to elucidate myocilin function(s). We identified α1-syntrophin, a component of the dystrophin-associated protein complex (DAPC), as a myocilin-binding candidate. Myocilin interacted with α1-syntrophin via its N-terminal domain and co-immunoprecipitated with α1-syntrophin from C2C12 myotubes and mouse skeletal muscle. Expression of 15-fold higher levels of myocilin in the muscles of transgenic mice led to the elevated association of α1-syntrophin, neuronal nitric-oxide synthase, and α-dystroglycan with DAPC, which increased the binding of laminin to α-dystroglycan and Akt signaling. Phosphorylation of Akt and Forkhead box O-class 3, key regulators of muscle size, was increased more than 3-fold, whereas the expression of muscle-specific RING finger protein-1 and atrogin-1, muscle atrophy markers, was decreased by 79 and 88%, respectively, in the muscles of transgenic mice. Consequently, the average size of muscle fibers of the transgenic mice was increased by 36% relative to controls. We suggest that intracellular myocilin plays a role as a regulator of muscle hypertrophy pathways, acting through the components of DAPC.
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Affiliation(s)
- Myung Kuk Joe
- Retinal Ganglion Cell Biology Section, Laboratory of Retinal Cell and Molecular Biology, NEI, National Institutes of Health, Bethesda, Maryland 20892, USA
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12
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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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Jørgensen LH, Blain A, Greally E, Laval SH, Blamire AM, Davison BJ, Brinkmeier H, MacGowan GA, Schrøder HD, Bushby K, Straub V, Lochmüller H. Long-term blocking of calcium channels in mdx mice results in differential effects on heart and skeletal muscle. THE AMERICAN JOURNAL OF PATHOLOGY 2010; 178:273-83. [PMID: 21224064 PMCID: PMC3016598 DOI: 10.1016/j.ajpath.2010.11.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2010] [Revised: 08/19/2010] [Accepted: 09/21/2010] [Indexed: 02/01/2023]
Abstract
The disease mechanisms underlying dystrophin-deficient muscular dystrophy are complex, involving not only muscle membrane fragility, but also dysregulated calcium homeostasis. Specifically, it has been proposed that calcium channels directly initiate a cascade of pathological events by allowing calcium ions to enter the cell. The objective of this study was to investigate the effect of chronically blocking calcium channels with the aminoglycoside antibiotic streptomycin from onset of disease in the mdx mouse model of Duchenne muscular dystrophy (DMD). Treatment in utero onwards delayed onset of dystrophic symptoms in the limb muscle of young mdx mice, but did not prevent degeneration and regeneration events occurring later in the disease course. Long-term treatment had a positive effect on limb muscle pathology, reduced fibrosis, increased sarcolemmal stability, and promoted muscle regeneration in older mice. However, streptomycin treatment did not show positive effects in diaphragm or heart muscle, and heart pathology was worsened. Thus, blocking calcium channels even before disease onset does not prevent dystrophy, making this an unlikely treatment for DMD. These findings highlight the importance of analyzing several time points throughout the life of the treated mice, as well as analyzing many tissues, to get a complete picture of treatment efficacy.
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Affiliation(s)
- Louise H. Jørgensen
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
- Institute of Clinical Research, University of Southern Denmark, Odense C, Denmark
| | - Alison Blain
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Elizabeth Greally
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Steve H. Laval
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andrew M. Blamire
- Institute of Cellular Medicine and Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Benjamin J. Davison
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Heinrich Brinkmeier
- Institute of Pathophysiology, Ernst Moritz Arndt University of Greifswald, Karlsburg, Germany
| | - Guy A. MacGowan
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
- Department of Cardiology, Freeman Hospital, Newcastle upon Tyne, United Kingdom
| | - Henrik D. Schrøder
- Department of Clinical Pathology, University of Southern Denmark, Odense C, Denmark
| | - Kate Bushby
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Volker Straub
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Hanns Lochmüller
- Institute of Human Genetics, International Centre of Life, Newcastle University, Newcastle upon Tyne, United Kingdom
- Address reprint requests to Professor Hanns Lochmüller, MD, Institute of Human Genetics, International Centre for Life, Newcastle University, Central Parkway, Newcastle upon Tyne, NE1 3BZ, United Kingdom
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14
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Li D, Long C, Yue Y, Duan D. Sub-physiological sarcoglycan expression contributes to compensatory muscle protection in mdx mice. Hum Mol Genet 2009; 18:1209-20. [PMID: 19131360 PMCID: PMC2655768 DOI: 10.1093/hmg/ddp015] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2008] [Revised: 12/31/2008] [Accepted: 01/06/2009] [Indexed: 12/11/2022] Open
Abstract
Sarcoglycans are a group of single-pass transmembrane glycoproteins. In striated muscle, sarcoglycans interact with dystrophin and other dystrophin-associated proteins (DAPs) to form the dystrophin-associated glycoprotein complex (DGC). The DGC protects the sarcolemma from contraction-induced injury. Duchenne muscular dystrophy (DMD) is caused by dystrophin gene mutations. In the absence of dystrophin, the DGC is disassembled from the sarcolemma. This initiates a chain reaction of muscle degeneration, necrosis, inflammation and fibrosis. In contrast to human patients, dystrophin-null mdx mice are only mildly affected. Enhanced muscle regeneration and the up-regulation of utrophin and integrin are thought to protect mdx muscle. Interestingly, trace amounts of sarcoglycans and other DAPs can be detected at the mdx sarcolemma. It is currently unclear whether sub-physiological sarcoglycan expression also contributes to the mild phenotype in mdx mice. To answer this question, we generated delta-sarcoglycan/dystrophin double knockout mice (delta-Dko) in which residual sarcoglycans were completely eliminated from the sarcolemma. Interestingly, utrophin levels were further increased in these mice. However, enhanced utrophin expression did not mitigate disease. The clinical manifestation of delta-Dko mice was worse than that of mdx mice. They showed characteristic dystrophic signs, body emaciation and more macrophage infiltration. Their lifespan was reduced by 60%. Furthermore, delta-Dko muscle generated significantly less absolute muscle force and became more susceptible to contraction-induced injury. Our results suggest that sub-physiological sarcoglycan expression plays a critical role in ameliorating muscle disease in mdx mice. We speculate that low-level sarcoglycan expression may represent a useful strategy to palliate DMD.
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Affiliation(s)
| | | | | | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, The University of Missouri, Columbia, MO, USA
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