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Poggio E, Barazzuol L, Salmaso A, Milani C, Deligiannopoulou A, Cazorla ÁG, Jang SS, Juliá-Palacios N, Keren B, Kopajtich R, Lynch SA, Mignot C, Moorwood C, Neuhofer C, Nigro V, Oostra A, Prokisch H, Saillour V, Schuermans N, Torella A, Verloo P, Yazbeck E, Zollino M, Jech R, Winkelmann J, Necpal J, Calì T, Brini M, Zech M. ATP2B2 de novo variants as a cause of variable neurodevelopmental disorders that feature dystonia, ataxia, intellectual disability, behavioral symptoms, and seizures. Genet Med 2023; 25:100971. [PMID: 37675773 DOI: 10.1016/j.gim.2023.100971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Revised: 08/28/2023] [Accepted: 08/29/2023] [Indexed: 09/08/2023] Open
Abstract
PURPOSE ATP2B2 encodes the variant-constrained plasma-membrane calcium-transporting ATPase-2, expressed in sensory ear cells and specialized neurons. ATP2B2/Atp2b2 variants were previously linked to isolated hearing loss in patients and neurodevelopmental deficits with ataxia in mice. We aimed to establish the association between ATP2B2 and human neurological disorders. METHODS Multinational case recruitment, scrutiny of trio-based genomics data, in silico analyses, and functional variant characterization were performed. RESULTS We assembled 7 individuals harboring rare, predicted deleterious heterozygous ATP2B2 variants. The alleles comprised 5 missense substitutions that affected evolutionarily conserved sites and 2 frameshift variants in the penultimate exon. For 6 variants, a de novo status was confirmed. Unlike described patients with hearing loss, the individuals displayed a spectrum of neurological abnormalities, ranging from ataxia with dystonic features to complex neurodevelopmental manifestations with intellectual disability, autism, and seizures. Two cases with recurrent amino-acid variation showed distinctive overlap with cerebellar atrophy-associated ataxia and epilepsy. In cell-based studies, all variants caused significant alterations in cytosolic calcium handling with both loss- and gain-of-function effects. CONCLUSION Presentations in our series recapitulate key phenotypic aspects of Atp2b2-mouse models and underline the importance of precise calcium regulation for neurodevelopment and cerebellar function. Our study documents a role for ATP2B2 variants in causing heterogeneous neurodevelopmental and movement-disorder syndromes.
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Affiliation(s)
- Elena Poggio
- Department of Biology, University of Padua, Padua, Italy
| | - Lucia Barazzuol
- Department of Biomedical Sciences, University of Padua, Padua, Italy
| | - Andrea Salmaso
- Department of Biology, University of Padua, Padua, Italy
| | - Celeste Milani
- Department of Biology, University of Padua, Padua, Italy
| | | | - Ángeles García Cazorla
- European Reference Network for Hereditary Metabolic Diseases (MetabERN), Madrid, Spain; Neurometabolic Unit and Synaptic Metabolism Laboratory, Neurology Department Sant Joan de Déu Hospital, IPR, Barcelona, Spain; Centro de Investigación Biomédica en Red de Enfermedades Raras (CIBERER), Instituto de Salud Carlos III, Madrid, Spain
| | - Se Song Jang
- Seoul National University (SNU) College of Medicine, Seoul, South Korea
| | - Natalia Juliá-Palacios
- Neurology Department, Neurometabolic Unit, Institut de Recerca, CIBERER and MetabERN, Hospital Sant Joan de Déu, Barcelona, Spain
| | - Boris Keren
- APHP.Sorbonne Université, Department of Medical Genetics, Pitié-Salpêtrière University Hospital, and Centre de Référence Maladies Rares Déficiences Intellectuelles de Causes Rares, Paris, France
| | - Robert Kopajtich
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Sally Ann Lynch
- Department of Clinical Genetics, Temple Street Children's University Hospital, Dublin, Ireland
| | - Cyril Mignot
- APHP.Sorbonne Université, Department of Medical Genetics, Pitié-Salpêtrière University Hospital, and Centre de Référence Maladies Rares Déficiences Intellectuelles de Causes Rares, Paris, France
| | - Catherine Moorwood
- Exeter Genomics Laboratory, Royal Devon University Healthcare NHS Foundation Trust, Exeter, United Kingdom
| | - Christiane Neuhofer
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Vincenzo Nigro
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, Napoli, Italy
| | - Anna Oostra
- Department of Pediatrics, Division of Pediatric Neurology and Metabolism, Ghent University Hospital, Ghent, Belgium
| | - Holger Prokisch
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany
| | - Virginie Saillour
- Laboratoire de biologie médicale multisites Seqoia - FMG2025, Paris, France
| | - Nika Schuermans
- Center for Medical Genetics Ghent, Ghent University Hospital, Ghent, Belgium; Department of Biomolecular Medicine, Ghent University Hospital, Ghent, Belgium
| | - Annalaura Torella
- Department of Precision Medicine, University of Campania, Luigi Vanvitelli, Napoli, Italy
| | - Patrick Verloo
- Department of Pediatric Neurology, Center for Inherited Metabolic Disorders and metabERN, University Hospital Ghent, Ghent, Belgium
| | - Elise Yazbeck
- Pediatric Neurology Department, Assistance Publique-Hôpitaux de Paris, Hôpitaux Universitaires Paris Saclay, Bicêtre Hospital, Le Kremlin Bicêtre, France
| | - Marcella Zollino
- Unit of Medical Genetics, Section of Genomic Medicine, Department of Life Sciences and Public Health, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario A. Gemelli IRCCS, Rome, Italy
| | - Robert Jech
- Department of Neurology, Charles University in Prague, 1st Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic
| | - Juliane Winkelmann
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany; Munich Cluster for Systems Neurology, SyNergy, Munich, Germany
| | - Jan Necpal
- 2nd Department of Neurology, Faculty of Medicine, Comenius University, Bratislava, Slovakia; Department of Neurology, Zvolen Hospital, Zvolen, Slovakia
| | - Tito Calì
- Department of Biomedical Sciences, University of Padua, Padua, Italy; Centro Studi per la Neurodegenerazione (CESNE), University of Padua, Padua, Italy; Neuroscience Center (PNC), University of Padua, Padua, Italy
| | - Marisa Brini
- Department of Biology, University of Padua, Padua, Italy; Centro Studi per la Neurodegenerazione (CESNE), University of Padua, Padua, Italy
| | - Michael Zech
- Institute of Neurogenomics, Helmholtz Zentrum München, Munich, Germany; Institute of Human Genetics, School of Medicine, Technical University of Munich, Munich, Germany; Institute for Advanced Study, Technical University of Munich, Garching, Germany.
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Moorwood C, Philippou A, Spinazzola J, Keyser B, Macarak EJ, Barton ER. Absence of γ-sarcoglycan alters the response of p70S6 kinase to mechanical perturbation in murine skeletal muscle. Skelet Muscle 2014; 4:13. [PMID: 25024843 PMCID: PMC4095884 DOI: 10.1186/2044-5040-4-13] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Accepted: 05/29/2014] [Indexed: 12/18/2022] Open
Abstract
Background The dystrophin glycoprotein complex (DGC) is located at the sarcolemma of muscle fibers, providing structural integrity. Mutations in and loss of DGC proteins cause a spectrum of muscular dystrophies. When only the sarcoglycan subcomplex is absent, muscles display severe myofiber degeneration, but little susceptibility to contractile damage, suggesting that disease occurs not by structural deficits but through aberrant signaling, namely, loss of normal mechanotransduction signaling through the sarcoglycan complex. We extended our previous studies on mechanosensitive, γ-sarcoglycan-dependent ERK1/2 phosphorylation, to determine whether additional pathways are altered with the loss of γ-sarcoglycan. Methods We examined mechanotransduction in the presence and absence of γ-sarcoglycan, using C2C12 myotubes, and primary cultures and isolated muscles from C57Bl/6 (C57) and γ-sarcoglycan-null (γ-SG-/-) mice. All were subjected to cyclic passive stretch. Signaling protein phosphorylation was determined by immunoblotting of lysates from stretched and non-stretched samples. Calcium dependence was assessed by maintaining muscles in calcium-free or tetracaine-supplemented Ringer’s solution. Dependence on mTOR was determined by stretching isolated muscles in the presence or absence of rapamycin. Results C2C12 myotube stretch caused a robust increase in P-p70S6K, but decreased P-FAK and P-ERK2. Neither Akt nor ERK1 were responsive to passive stretch. Similar but non-significant trends were observed in C57 primary cultures in response to stretch, and γ-SG-/- cultures displayed no p70S6K response. In contrast, in isolated muscles, p70S6K was mechanically responsive. Basal p70S6K activation was elevated in muscles of γ-SG-/- mice, in a calcium-independent manner. p70S6K activation increased with stretch in both C57 and γ-SG-/- isolated muscles, and was sustained in γ-SG-/- muscles, unlike the transient response in C57 muscles. Rapamycin treatment blocked all of p70S6K activation in stretched C57 muscles, and reduced downstream S6RP phosphorylation. However, even though rapamycin treatment decreased p70S6K activation in stretched γ-SG-/- muscles, S6RP phosphorylation remained elevated. Conclusions p70S6K is an important component of γ-sarcoglycan-dependent mechanotransduction in skeletal muscle. Our results suggest that loss of γ-sarcoglycan uncouples the response of p70S6K to stretch and implies that γ-sarcoglycan is important for inactivation of this pathway. Overall, we assert that altered load-sensing mechanisms exist in muscular dystrophies where the sarcoglycans are absent.
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Affiliation(s)
- Catherine Moorwood
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA ; Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Anastassios Philippou
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA ; Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA ; Current address: Department of Physiology, Medical School, National and Kapodistrian University of Athens, Goudi, Athens, Greece
| | - Janelle Spinazzola
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA ; Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Benjamin Keyser
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Edward J Macarak
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA ; Current address: Department of Dermatology and Cutaneous Biology, Jefferson University College of Medicine, Philadelphia, PA, USA
| | - Elisabeth R Barton
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA, USA ; Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
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Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin. Several downstream consequences of dystrophin deficiency are triggers of endoplasmic reticulum (ER) stress, including loss of calcium homeostasis, hypoxia and oxidative stress. During ER stress, misfolded proteins accumulate in the ER lumen and the unfolded protein response (UPR) is triggered, leading to adaptation or apoptosis. We hypothesized that ER stress is heightened in dystrophic muscles and contributes to the pathology of DMD. We observed increases in the ER stress markers BiP and cleaved caspase-4 in DMD patient biopsies, compared with controls, and an increase in multiple UPR pathways in muscles of the dystrophin-deficient mdx mouse. We then crossed mdx mice with mice null for caspase-12, the murine equivalent of human caspase-4, which are resistant to ER stress. We found that deleting caspase-12 preserved mdx muscle function, resulting in a 75% recovery of both specific force generation and resistance to eccentric contractions. The compensatory hypertrophy normally found in mdx muscles was normalized in the absence of caspase-12; this was found to be due to decreased fibre sizes, and not to a fibre type shift or a decrease in fibrosis. Fibre central nucleation was not significantly altered in the absence of caspase-12, but muscle fibre degeneration found in the mdx mouse was reduced almost to wild-type levels. In conclusion, we have identified heightened ER stress and abnormal UPR signalling as novel contributors to the dystrophic phenotype. Caspase-4 is therefore a potential therapeutic target for DMD.
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Affiliation(s)
- Catherine Moorwood
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
| | - Elisabeth R Barton
- Department of Anatomy and Cell Biology, University of Pennsylvania School of Dental Medicine, Philadelphia, PA, USA and Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA, USA
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Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is a devastating genetic muscle wasting disease caused by mutations in the DMD gene that in turn lead to an absence of dystrophin. Currently, there is no definitive therapy for DMD. Gene- and cell-based therapies designed to replace dystrophin have met some degree of success, as have strategies that seek to improve the dystrophic pathology independent of dystrophin. AREAS COVERED In this review the authors focus on utrophin promoter activation-based strategies and their implications on potential therapeutics for DMD. These strategies in common are designed to identify drugs/small molecules that can activate the utrophin promoter and would allow the functional substitution of dystrophin by upregulating utrophin expression in dystrophic muscle. The authors provide an overview of utrophin biology with a focus on regulation of the utrophin promoter and discuss current attempts in identifying utrophin promoter-activating molecules using high-throughput screening (HTS). EXPERT OPINION The characterisation of utrophin promoter regulatory mechanisms coupled with advances in HTS have allowed researchers to undertake screens and identify a number of promising lead compounds that may prove useful for DMD. In principle, these pharmacological compounds offer significant advantages from a translational viewpoint for developing DMD therapeutics.
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Affiliation(s)
- Catherine Moorwood
- University of Pennsylvania School of Dental Medicine, Department of Anatomy & Cell Biology, 438 Levy Research Building, 240 S. 40th Street, Philadelphia, PA 19104, USA
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Moorwood C, Liu M, Tian Z, Barton ER. Isometric and eccentric force generation assessment of skeletal muscles isolated from murine models of muscular dystrophies. J Vis Exp 2013:e50036. [PMID: 23407283 DOI: 10.3791/50036] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Critical to the evaluation of potential therapeutics for muscular disease are sensitive and reproducible physiological assessments of muscle function. Because many pre-clinical trials rely on mouse models for these diseases, isolated muscle function has become one of the standards for Go/NoGo decisions in moving drug candidates forward into patients. We will demonstrate the preparation of the extensor digitorum longus (EDL) and diaphragm muscles for functional testing, which are the predominant muscles utilized for these studies. The EDL muscle geometry is ideal for isolated muscle preparations, with two easily accessible tendons, and a small size that can be supported by superfusion in a bath. The diaphragm exhibits profound progressive pathology in dystrophic animals, and can serve as a platform for evaluating many potential therapies countering fibrosis, and promoting myofiber stability. Protocols for routine testing, including isometric and eccentric contractions, will be shown. Isometric force provides assessment of strength, and eccentric contractions help to evaluate sarcolemma stability, which is disrupted in many types of muscular dystrophies. Comparisons of the expected results between muscles from wildtype and dystrophic muscles will also be provided. These measures can complement morphological and biochemical measurements of tissue homeostasis, as well as whole animal assessments of muscle function.
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Affiliation(s)
- Catherine Moorwood
- Department of Anatomy and Cell Biology, School of Dental Medicine, University of Pennsylvania, USA
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Moorwood C, Soni N, Patel G, Wilton SD, Khurana TS. A cell-based high-throughput screening assay for posttranscriptional utrophin upregulation. ACTA ACUST UNITED AC 2012; 18:400-6. [PMID: 23112083 DOI: 10.1177/1087057112465648] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle-wasting disease caused by mutations in the dystrophin gene. Utrophin is a homologue of dystrophin that can compensate for its absence when overexpressed in DMD animal models. Utrophin upregulation is therefore a promising therapeutic approach for DMD. Utrophin is regulated at both transcriptional and posttranscriptional levels. Transcriptional regulation has been studied extensively, and assays have been described for the identification of utrophin promoter-targeting molecules. However, despite the profound impact that posttranscriptional regulation has on utrophin expression, screening assays have not yet been described that could be used to discover pharmaceuticals targeting this key phase of regulation. We describe the development and validation of a muscle cell line-based assay in which a stably expressed luciferase coding sequence is flanked by the utrophin 5'- and 3'-untranslated regions (UTRs). The assay was validated using the posttranscriptional regulation of utrophin by miR-206. The assay has a Z' of 0.7, indicating robust performance in high-throughput format. This assay can be used to study utrophin regulatory mechanisms or to screen chemical libraries for compounds that upregulate utrophin posttranscriptionally via its UTRs. Compounds identified via this assay, used alone or in a synergistic combination with utrophin promoter-targeting molecules, would be predicted to have therapeutic potential for DMD.
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Affiliation(s)
- Catherine Moorwood
- University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Abstract
BACKGROUND Utrophin is the autosomal homolog of dystrophin, the product of the Duchenne Muscular Dystrophy (DMD) locus. Its regulation is of therapeutic interest as its overexpression can compensate for dystrophin's absence in animal models of DMD. The tissue distribution and transcriptional regulation of utrophin have been characterized extensively, and more recently translational control mechanisms that may underlie its complex expression patterns have begun to be identified. METHODOLOGY/PRINCIPAL FINDINGS Using a variety of bioinformatic, molecular and cell biology techniques, we show that the muscle isoform utrophin-A is predominantly suppressed at the translational level in C2C12 myoblasts. The extent of translational inhibition is estimated to be ~99% in C2C12 cells and is mediated by both the 5'- and 3'-UTRs of the utrophin-A mRNA. In this study we identify five miRNAs (let-7c, miR-150, miR-196b, miR-296-5p, miR-133b) that mediate the repression, and confirm repression by the previously identified miR-206. We demonstrate that this translational repression can be overcome by blocking the actions of miRNAs, resulting in an increased level of utrophin protein in C2C12 cells. CONCLUSIONS/SIGNIFICANCE The present study has identified key inhibitory mechanisms featuring miRNAs that regulate utrophin expression, and demonstrated that these mechanisms can be targeted to increase endogenous utrophin expression in cultured muscle cells. We suggest that miRNA-mediated inhibitory mechanisms could be targeted by methods similar to those described here as a novel strategy to increase utrophin expression as a therapy for DMD.
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Affiliation(s)
- Utpal Basu
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Olga Lozynska
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Catherine Moorwood
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gopal Patel
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Steve D. Wilton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Perth, Australia
| | - Tejvir S. Khurana
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Moorwood C, Lozynska O, Suri N, Napper AD, Diamond SL, Khurana TS. Drug discovery for Duchenne muscular dystrophy via utrophin promoter activation screening. PLoS One 2011; 6:e26169. [PMID: 22028826 PMCID: PMC3197614 DOI: 10.1371/journal.pone.0026169] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 09/21/2011] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is a devastating muscle wasting disease caused by mutations in dystrophin, a muscle cytoskeletal protein. Utrophin is a homologue of dystrophin that can functionally compensate for its absence when expressed at increased levels in the myofibre, as shown by studies in dystrophin-deficient mice. Utrophin upregulation is therefore a promising therapeutic approach for DMD. The use of a small, drug-like molecule to achieve utrophin upregulation offers obvious advantages in terms of delivery and bioavailability. Furthermore, much of the time and expense involved in the development of a new drug can be eliminated by screening molecules that are already approved for clinical use. METHODOLOGY/PRINCIPAL FINDINGS We developed and validated a cell-based, high-throughput screening assay for utrophin promoter activation, and used it to screen the Prestwick Chemical Library of marketed drugs and natural compounds. Initial screening produced 20 hit molecules, 14 of which exhibited dose-dependent activation of the utrophin promoter and were confirmed as hits. Independent validation demonstrated that one of these compounds, nabumetone, is able to upregulate endogenous utrophin mRNA and protein, in C2C12 muscle cells. CONCLUSIONS/SIGNIFICANCE We have developed a cell-based, high-throughput screening utrophin promoter assay. Using this assay, we identified and validated a utrophin promoter-activating drug, nabumetone, for which pharmacokinetics and safety in humans are already well described, and which represents a lead compound for utrophin upregulation as a therapy for DMD.
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Affiliation(s)
- Catherine Moorwood
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Olga Lozynska
- Penn Center for Molecular Discovery, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Neha Suri
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
| | - Andrew D. Napper
- Penn Center for Molecular Discovery, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Scott L. Diamond
- Penn Center for Molecular Discovery, Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Tejvir S. Khurana
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail:
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Clarke WT, Edwards B, McCullagh KJA, Kemp MW, Moorwood C, Sherman DL, Burgess M, Davies KE. Syncoilin modulates peripherin filament networks and is necessary for large-calibre motor neurons. J Cell Sci 2010; 123:2543-52. [PMID: 20587592 DOI: 10.1242/jcs.059113] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Syncoilin is an atypical type III intermediate filament (IF) protein, which is expressed in muscle and is associated with the dystrophin-associated protein complex. Here, we show that syncoilin is expressed in both the central and peripheral nervous systems. Isoform Sync1 is dominant in the brain, but isoform Sync2 is dominant in the spinal cord and sciatic nerve. Peripherin is a type III IF protein that has been shown to colocalise and interact with syncoilin. Our analyses suggest that syncoilin might function to modulate formation of peripherin filament networks through binding to peripherin isoforms. Peripherin is associated with the disease amyotrophic lateral sclerosis (ALS), thus establishing a link between syncoilin and ALS. A neuronal analysis of the syncoilin-null mouse (Sync(-/-)) revealed a reduced ability in accelerating treadmill and rotarod tests. This phenotype might be attributable to the impaired function of extensor digitorum longus muscle and type IIb fibres caused by a shift from large- to small-calibre motor axons in the ventral root.
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Affiliation(s)
- W Thomas Clarke
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford, OX1 3PT, UK
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Moorwood C. Syncoilin, an intermediate filament-like protein linked to the dystrophin associated protein complex in skeletal muscle. Cell Mol Life Sci 2008; 65:2957-63. [PMID: 18810324 DOI: 10.1007/s00018-008-8306-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Syncoilin is a member of the intermediate filament protein family, highly expressed in skeletal and cardiac muscle. Syncoilin binds alpha-dystrobrevin, a component of the dystrophin associated protein complex (DAPC) located at the muscle cell membrane, and desmin, a muscle-specific intermediate filament protein, thus providing a link between the DAPC and the muscle intermediate filament network. This link may be important for muscle integrity and force transduction during contraction, a theory that is supported by the reduced force-generating capacity of muscles from syncoilin-null mice. Additionally, syncoilin is found at increased levels in the regenerating muscle fibres of patients with muscular dystrophies and mouse models of muscle disease. Therefore, syncoilin may be important for muscle regeneration in response to injury. The aims of this article are to review current knowledge about syncoilin and to discuss its possible functions in skeletal muscle.
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Affiliation(s)
- C Moorwood
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania, A601 Richards Building, 3700 Hamilton Walk, Philadelphia, PA, 19104, USA.
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