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Mokhonova EI, Malik R, Mamsa H, Walker J, Gibbs EM, Crosbie RH. The Development of Robust Antibodies to Sarcospan, a Dystrophin- and Integrin-Associated Protein, for Basic and Translational Research. Int J Mol Sci 2024; 25:6121. [PMID: 38892308 PMCID: PMC11173052 DOI: 10.3390/ijms25116121] [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: 04/13/2024] [Revised: 05/25/2024] [Accepted: 05/27/2024] [Indexed: 06/21/2024] Open
Abstract
Sarcospan (SSPN) is a 25-kDa transmembrane protein that is broadly expressed at the cell surface of many tissues, including, but not limited to, the myofibers from skeletal and smooth muscles, cardiomyocytes, adipocytes, kidney epithelial cells, and neurons. SSPN is a core component of the dystrophin-glycoprotein complex (DGC) that links the intracellular actin cytoskeleton with the extracellular matrix. It is also associated with integrin α7β1, the predominant integrin expressed in skeletal muscle. As a tetraspanin-like protein with four transmembrane spanning domains, SSPN functions as a scaffold to facilitate protein-protein interactions at the cell membrane. Duchenne muscular dystrophy, Becker muscular dystrophy, and X-linked dilated cardiomyopathy are caused by the loss of dystrophin at the muscle cell surface and a concomitant loss of the entire DGC, including SSPN. SSPN overexpression ameliorates Duchenne muscular dystrophy in the mdx murine model, which supports SSPN being a viable therapeutic target. Other rescue studies support SSPN as a biomarker for the proper assembly and membrane expression of the DGC. Highly specific and robust antibodies to SSPN are needed for basic research on the molecular mechanisms of SSPN rescue, pre-clinical studies, and biomarker evaluations in human samples. The development of SSPN antibodies is challenged by the presence of its four transmembrane domains and limited antigenic epitopes. To address the significant barrier presented by limited commercially available antibodies, we aimed to generate a panel of robust SSPN-specific antibodies that can serve as a resource for the research community. We created antibodies to three SSPN protein epitopes, including the intracellular N- and C-termini as well as the large extracellular loop (LEL) between transmembrane domains 3 and 4. We developed a panel of rabbit antibodies (poly- and monoclonal) against an N-terminal peptide fragment of SSPN. We used several assays to show that the rabbit antibodies recognize mouse SSPN with a high functional affinity and specificity. We developed mouse monoclonal antibodies against the C-terminal peptide and the large extracellular loop of human SSPN. These antibodies are superior to commercially available antibodies and outperform them in various applications, including immunoblotting, indirect immunofluorescence analysis, immunoprecipitation, and an ELISA. These newly developed antibodies will significantly improve the quality and ease of SSPN detection for basic and translational research.
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Affiliation(s)
- Ekaterina I. Mokhonova
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Ravinder Malik
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Hafsa Mamsa
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Jackson Walker
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Elizabeth M. Gibbs
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Rachelle H. Crosbie
- Department of Integrative Biology and Physiology, University of California Los Angeles, Los Angeles, CA 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California Los Angeles, Los Angeles, CA 90095, USA
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA 90095, USA
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Stearns-Reider KM, Hicks MR, Hammond KG, Reynolds JC, Maity A, Kurmangaliyev YZ, Chin J, Stieg AZ, Geisse NA, Hohlbauch S, Kaemmer S, Schmitt LR, Pham TT, Yamauchi K, Novitch BG, Wollman R, Hansen KC, Pyle AD, Crosbie RH. Myoscaffolds reveal laminin scarring is detrimental for stem cell function while sarcospan induces compensatory fibrosis. NPJ Regen Med 2023; 8:16. [PMID: 36922514 PMCID: PMC10017766 DOI: 10.1038/s41536-023-00287-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 02/22/2023] [Indexed: 03/18/2023] Open
Abstract
We developed an on-slide decellularization approach to generate acellular extracellular matrix (ECM) myoscaffolds that can be repopulated with various cell types to interrogate cell-ECM interactions. Using this platform, we investigated whether fibrotic ECM scarring affected human skeletal muscle progenitor cell (SMPC) functions that are essential for myoregeneration. SMPCs exhibited robust adhesion, motility, and differentiation on healthy muscle-derived myoscaffolds. All SPMC interactions with fibrotic myoscaffolds from dystrophic muscle were severely blunted including reduced motility rate and migration. Furthermore, SMPCs were unable to remodel laminin dense fibrotic scars within diseased myoscaffolds. Proteomics and structural analysis revealed that excessive collagen deposition alone is not pathological, and can be compensatory, as revealed by overexpression of sarcospan and its associated ECM receptors in dystrophic muscle. Our in vivo data also supported that ECM remodeling is important for SMPC engraftment and that fibrotic scars may represent one barrier to efficient cell therapy.
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Affiliation(s)
- Kristen M Stearns-Reider
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Orthopaedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Michael R Hicks
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Physiology and Biophysics, University of California, Irvine, Irvine, CA, 92697, USA
| | - Katherine G Hammond
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Joseph C Reynolds
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Alok Maity
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Yerbol Z Kurmangaliyev
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Biological Chemistry, HHMI, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Jesse Chin
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Adam Z Stieg
- California NanoSystems Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | | | - Sophia Hohlbauch
- Asylum Research, An Oxford Instruments Company, Santa Barbara, CA, 93117, USA
| | - Stefan Kaemmer
- Park Systems, 3040 Olcott St, Santa Clara, CA, 95054, USA
| | - Lauren R Schmitt
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, Aurora, CO, 80045, USA
| | - Thanh T Pham
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, Aurora, CO, 80045, USA
| | - Ken Yamauchi
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Bennett G Novitch
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Neurobiology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Intellectual and Developmental Disabilities Research Center, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, 90095, USA
| | - Roy Wollman
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Institute for Quantitative and Computational Biology, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Kirk C Hansen
- Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, Aurora, CO, 80045, USA
| | - April D Pyle
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Rachelle H Crosbie
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, 90095, USA.
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Mamsa H, Stark RL, Shin KM, Beedle AM, Crosbie RH. Sarcospan increases laminin-binding capacity of α-dystroglycan to ameliorate DMD independent of Galgt2. Hum Mol Genet 2022; 31:718-732. [PMID: 34581784 PMCID: PMC8895749 DOI: 10.1093/hmg/ddab276] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 08/27/2021] [Accepted: 09/13/2021] [Indexed: 11/14/2022] Open
Abstract
In Duchenne muscular dystrophy (DMD), mutations in dystrophin result in a loss of the dystrophin-glycoprotein complex (DGC) at the myofiber membrane, which functions to connect the extracellular matrix with the intracellular actin cytoskeleton. The dystroglycan subcomplex interacts with dystrophin and spans the sarcolemma where its extensive carbohydrates (matriglycan and CT2 glycan) directly interact with the extracellular matrix. In the current manuscript, we show that sarcospan overexpression enhances the laminin-binding capacity of dystroglycan in DMD muscle by increasing matriglycan glycosylation of α-dystroglycan. Furthermore, we find that this modification is not affected by loss of Galgt2, a glycotransferase, which catalyzes the CT2 glycan. Our findings reveal that the matriglycan carbohydrates, and not the CT2 glycan, are necessary for sarcospan-mediated amelioration of DMD. Overexpression of Galgt2 in the DMD mdx murine model prevents muscle pathology by increasing CT2 modified α-dystroglycan. Galgt2 also increases expression of utrophin, which compensates for the loss of dystrophin in DMD muscle. We found that combined loss of Galgt2 and dystrophin reduced utrophin expression; however, it did not interfere with sarcospan rescue of disease. These data reveal a partial dependence of sarcospan on Galgt2 for utrophin upregulation. In addition, sarcospan alters the cross-talk between the adhesion complexes by decreasing the association of integrin β1D with dystroglycan complexes. In conclusion, sarcospan functions to re-wire the cell to matrix connections by strengthening the cellular adhesion and signaling, which, in turn, increases the resilience of the myofiber membrane.
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Affiliation(s)
- Hafsa Mamsa
- Department of Integrative Biology & Physiology, University of California, Los Angeles 90095, USA
| | - Rachelle L Stark
- Department of Integrative Biology & Physiology, University of California, Los Angeles 90095, USA
| | - Kara M Shin
- Department of Integrative Biology & Physiology, University of California, Los Angeles 90095, USA
| | - Aaron M Beedle
- Department of Pharmaceutical Sciences, Binghamton University State University of New York, New York 13902, USA
| | - Rachelle H Crosbie
- Department of Integrative Biology & Physiology, University of California, Los Angeles 90095, USA
- Broad Stem Cell Institute, University of California, Los Angeles 90095, USA
- Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles 90095, USA
- Molecular Biology Institute, University of California, Los Angeles 90095, USA
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Shu C, Kaxon-Rupp AN, Collado JR, Damoiseaux R, Crosbie RH. Development of a high-throughput screen to identify small molecule enhancers of sarcospan for the treatment of Duchenne muscular dystrophy. Skelet Muscle 2019; 9:32. [PMID: 31831063 PMCID: PMC6907331 DOI: 10.1186/s13395-019-0218-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 12/04/2019] [Indexed: 01/14/2023] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is caused by loss of sarcolemma connection to the extracellular matrix. Transgenic overexpression of the transmembrane protein sarcospan (SSPN) in the DMD mdx mouse model significantly reduces disease pathology by restoring membrane adhesion. Identifying SSPN-based therapies has the potential to benefit patients with DMD and other forms of muscular dystrophies caused by deficits in muscle cell adhesion. METHODS Standard cloning methods were used to generate C2C12 myoblasts stably transfected with a fluorescence reporter for human SSPN promoter activity. Assay development and screening were performed in a core facility using liquid handlers and imaging systems specialized for use with a 384-well microplate format. Drug-treated cells were analyzed for target gene expression using quantitative PCR and target protein expression using immunoblotting. RESULTS We investigated the gene expression profiles of SSPN and its associated proteins during myoblast differentiation into myotubes, revealing an increase in expression after 3 days of differentiation. We created C2C12 muscle cells expressing an EGFP reporter for SSPN promoter activity and observed a comparable increase in reporter levels during differentiation. Assay conditions for high-throughput screening were optimized for a 384-well microplate format and a high-content imager for the visualization of reporter levels. We conducted a screen of 3200 compounds and identified seven hits, which include an overrepresentation of L-type calcium channel antagonists, suggesting that SSPN gene activity is sensitive to calcium. Further validation of a select hit revealed that the calcium channel inhibitor felodipine increased SSPN transcript and protein levels in both wild-type and dystrophin-deficient myotubes, without increasing differentiation. CONCLUSIONS We developed a stable muscle cell line containing the promoter region of the human SSPN protein fused to a fluorescent reporter. Using the reporter cells, we created and validated a scalable, cell-based assay that is able to identify compounds that increase SSPN promoter reporter, transcript, and protein levels in wild-type and dystrophin-deficient muscle cells.
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Affiliation(s)
- Cynthia Shu
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, USA.,Department of Integrative Biology and Physiology, University of California Los Angeles, 610 Charles E. Young Drive East, Terasaki Life Sciences Building, Los Angeles, CA, 90095, USA.,Center for Duchenne Muscular Dystrophy, University of California Los Angeles, Los Angeles, USA
| | - Ariana N Kaxon-Rupp
- Department of Integrative Biology and Physiology, University of California Los Angeles, 610 Charles E. Young Drive East, Terasaki Life Sciences Building, Los Angeles, CA, 90095, USA
| | - Judd R Collado
- Department of Integrative Biology and Physiology, University of California Los Angeles, 610 Charles E. Young Drive East, Terasaki Life Sciences Building, Los Angeles, CA, 90095, USA
| | - Robert Damoiseaux
- Department of Molecular and Medicinal Pharmacology, University of California Los Angeles, Los Angeles, USA.,California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Rachelle H Crosbie
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, USA. .,Department of Integrative Biology and Physiology, University of California Los Angeles, 610 Charles E. Young Drive East, Terasaki Life Sciences Building, Los Angeles, CA, 90095, USA. .,Center for Duchenne Muscular Dystrophy, University of California Los Angeles, Los Angeles, USA. .,Department of Neurology David Geffen School of Medicine, University of California Los Angeles, 610 Charles E. Young Drive East, Terasaki Life Sciences Building, Los Angeles, CA, 90095, USA.
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McMorran BJ, Miceli MC, Baum LG. Lectin-binding characterizes the healthy human skeletal muscle glycophenotype and identifies disease-specific changes in dystrophic muscle. Glycobiology 2017; 27:1134-1143. [PMID: 28973355 PMCID: PMC6283322 DOI: 10.1093/glycob/cwx073] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 08/08/2017] [Accepted: 08/21/2017] [Indexed: 12/27/2022] Open
Abstract
Our understanding of muscle glycosylation to date has derived from studies in mouse models and a limited number of human lectin histochemistry studies. As various therapeutic approaches aimed at treating patients with muscular dystrophies are being translated from rodent models to human, it is critical to better understand human muscle glycosylation and relevant disease-specific differences between healthy and dystrophic muscle. Here, we report the first quantitative characterization of human muscle glycosylation, and identify differentiation- and disease-specific differences in human muscle glycosylation. Utilizing a panel of 13 lectins with varying glycan specificities, we surveyed lectin binding to primary and immortalized myoblasts and myotubes from healthy and dystrophic sources. Following differentiation of primary and immortalized healthy human muscle cells, we observed increased binding of Narcissus pseudonarcissus agglutinin (NPA), PNA, MAA-II and WFA to myotubes compared to myoblasts. Following differentiation of immortalized healthy and dystrophic human muscle cells, we observed disease-specific differences in binding of NPA, Jac and Tricosanthes japonica agglutinin-I (TJA-I) to differentiated myotubes. We also observed differentiation- and disease-specific differences in binding of NPA, Jac, PNA, TJA-I and WFA to glycoprotein receptors in muscle cells. Additionally, Jac, PNA and WFA precipitated functionally glycosylated α-DG, that bound laminin, while NPA and TJA-I did not. Lectin histochemistry of healthy and dystrophic human muscle sections identified disease-specific differences in binding of O-glycan and sialic acid-specific lectins between healthy and dystrophic muscle. These results indicate that specific and discrete changes in glycosylation occur following differentiation, and identify specific lectins as potential biomarkers sensitive to changes in healthy human muscle glycosylation.
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Affiliation(s)
- Brian J McMorran
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave., CHS 14-127, Los Angeles, CA 90095, USA
| | - M Carrie Miceli
- Department of Microbiology, Immunology and Molecular Genetics, University of California Los Angeles, 609 Charles E Young Dr E, Los Angeles, CA 90095, USA
| | - Linda G Baum
- Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, 10833 Le Conte Ave., CHS 14-127, Los Angeles, CA 90095, USA
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Gibbs EM, Marshall JL, Ma E, Nguyen TM, Hong G, Lam JS, Spencer MJ, Crosbie-Watson RH. High levels of sarcospan are well tolerated and act as a sarcolemmal stabilizer to address skeletal muscle and pulmonary dysfunction in DMD. Hum Mol Genet 2017; 25:5395-5406. [PMID: 27798107 PMCID: PMC5418831 DOI: 10.1093/hmg/ddw356] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 10/13/2016] [Indexed: 12/27/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disorder that causes progressive muscle weakness, ultimately leading to early mortality in affected teenagers and young adults. Previous work from our lab has shown that a small transmembrane protein called sarcospan (SSPN) can enhance the recruitment of adhesion complex proteins to the cell surface. When human SSPN is expressed at three-fold levels in mdx mice, this increase in adhesion complex abundance improves muscle membrane stability, preventing many of the histopathological changes associated with DMD. However, expressing higher levels of human SSPN (ten-fold transgenic expression) causes a severe degenerative muscle phenotype in wild-type mice. Since SSPN-mediated stabilization of the sarcolemma represents a promising therapeutic strategy in DMD, it is important to determine whether SSPN can be introduced at high levels without toxicity. Here, we show that mouse SSPN (mSSPN) can be overexpressed at 30-fold levels in wild-type mice with no deleterious effects. In mdx mice, mSSPN overexpression improves dystrophic pathology and sarcolemmal stability. We show that these mice exhibit increased resistance to eccentric contraction-induced damage and reduced fatigue following exercise. mSSPN overexpression improved pulmonary function and reduced dystrophic histopathology in the diaphragm. Together, these results demonstrate that SSPN overexpression is well tolerated in mdx mice and improves sarcolemma defects that underlie skeletal muscle and pulmonary dysfunction in DMD.
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Affiliation(s)
- Elizabeth M Gibbs
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Jamie L Marshall
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Eva Ma
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Thien M Nguyen
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Grace Hong
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Jessica S Lam
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy
| | - Melissa J Spencer
- Center for Duchenne Muscular Dystrophy.,Molecular Biology Institute, University of California Los Angeles CA 90095, USA
| | - Rachelle H Crosbie-Watson
- Department of Integrative Biology and Physiology.,Center for Duchenne Muscular Dystrophy.,Department of Neurology David Geffen School of Medicine.,Molecular Biology Institute, University of California Los Angeles CA 90095, USA
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Alexander MS, Rozkalne A, Colletta A, Spinazzola JM, Johnson S, Rahimov F, Meng H, Lawlor MW, Estrella E, Kunkel LM, Gussoni E. CD82 Is a Marker for Prospective Isolation of Human Muscle Satellite Cells and Is Linked to Muscular Dystrophies. Cell Stem Cell 2016; 19:800-807. [PMID: 27641304 DOI: 10.1016/j.stem.2016.08.006] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Revised: 05/17/2016] [Accepted: 08/05/2016] [Indexed: 12/23/2022]
Abstract
Cell-surface markers for prospective isolation of stem cells from human skeletal muscle have been difficult to identify. Such markers would be powerful tools for studying satellite cell function during homeostasis and in pathogenesis of diseases such as muscular dystrophies. In this study, we show that the tetraspanin KAI/CD82 is an excellent marker for prospectively isolating stem cells from human fetal and adult skeletal muscle. Human CD82+ muscle cells robustly engraft into a mouse model of muscular dystrophy. shRNA knockdown of CD82 in myogenic cells reduces myoblast proliferation, suggesting it is functionally involved in muscle homeostasis. CD82 physically interacts with alpha7beta1 integrin (α7β1-ITG) and with α-sarcoglycan, a member of the Dystrophin-Associated Glycoprotein Complex (DAPC), both of which have been linked to muscular dystrophies. Consistently, CD82 expression is decreased in Duchenne muscular dystrophy patients. Together, these findings suggest that CD82 function may be important for muscle stem cell function in muscular disorders.
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Affiliation(s)
- Matthew S Alexander
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Stem Cell Program at Boston Children's Hospital, Boston, MA 02115, USA
| | - Anete Rozkalne
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Alessandro Colletta
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Boston University School of Medicine, Boston, MA 02215, USA
| | - Janelle M Spinazzola
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Stem Cell Program at Boston Children's Hospital, Boston, MA 02115, USA
| | - Samuel Johnson
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Fedik Rahimov
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Stem Cell Program at Boston Children's Hospital, Boston, MA 02115, USA
| | - Hui Meng
- Division of Pediatric Pathology, Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Michael W Lawlor
- Division of Pediatric Pathology, Department of Pathology and Laboratory Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Elicia Estrella
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Stem Cell Program at Boston Children's Hospital, Boston, MA 02115, USA; The Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Emanuela Gussoni
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; The Stem Cell Program at Boston Children's Hospital, Boston, MA 02115, USA.
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Abstract
Duchenne muscular dystrophy (DMD) is the most common form of muscular dystrophy in childhood. It is caused by mutations of the DMD gene, leading to progressive muscle weakness, loss of independent ambulation by early teens, and premature death due to cardiorespiratory complications. The diagnosis can usually be made after careful review of the history and examination of affected boys presenting with developmental delay, proximal weakness, and elevated serum creatine kinase, plus confirmation by muscle biopsy or genetic testing. Precise characterization of the DMD mutation is important for genetic counseling and individualized treatment. Current standard of care includes the use of corticosteroids to prolong ambulation and to delay the onset of secondary complications. Early use of cardioprotective agents, noninvasive positive pressure ventilation, and other supportive strategies has improved the life expectancy and health-related quality of life for many young adults with DMD. New emerging treatment includes viral-mediated microdystrophin gene replacement, exon skipping to restore the reading frame, and nonsense suppression therapy to allow translation and production of a modified dystrophin protein. Other potential therapeutic targets involve upregulation of compensatory proteins, reduction of the inflammatory cascade, and enhancement of muscle regeneration. So far, data from DMD clinical trials have shown limited success in delaying disease progression; unforeseen obstacles included immune response against the generated mini-dystrophin, inconsistent evidence of dystrophin production in muscle biopsies, and failure to demonstrate a significant improvement in the primary outcome measure, as defined by the 6-minute walk test in some studies. The long-term safety and efficacy of emerging treatments will depend on the selection of appropriate clinical end points and sensitive biomarkers to detect meaningful changes in disease progression. Correction of the underlying mutations using new gene-editing technologies and corticosteroid analogs with better safety profiles offers renewed hope for many individuals with DMD and their families.
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Affiliation(s)
- Jean K Mah
- Department of Pediatrics and Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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9
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Parvatiyar MS, Marshall JL, Nguyen RT, Jordan MC, Richardson VA, Roos KP, Crosbie-Watson RH. Sarcospan Regulates Cardiac Isoproterenol Response and Prevents Duchenne Muscular Dystrophy-Associated Cardiomyopathy. J Am Heart Assoc 2015; 4:JAHA.115.002481. [PMID: 26702077 PMCID: PMC4845268 DOI: 10.1161/jaha.115.002481] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background Duchenne muscular dystrophy is a fatal cardiac and skeletal muscle disease resulting from mutations in the dystrophin gene. We have previously demonstrated that a dystrophin‐associated protein, sarcospan (SSPN), ameliorated Duchenne muscular dystrophy skeletal muscle degeneration by activating compensatory pathways that regulate muscle cell adhesion (laminin‐binding) to the extracellular matrix. Conversely, loss of SSPN destabilized skeletal muscle adhesion, hampered muscle regeneration, and reduced force properties. Given the importance of SSPN to skeletal muscle, we investigated the consequences of SSPN ablation in cardiac muscle and determined whether overexpression of SSPN into mdx mice ameliorates cardiac disease symptoms associated with Duchenne muscular dystrophy cardiomyopathy. Methods and Results SSPN‐null mice exhibited cardiac enlargement, exacerbated cardiomyocyte hypertrophy, and increased fibrosis in response to β‐adrenergic challenge (isoproterenol; 0.8 mg/day per 2 weeks). Biochemical analysis of SSPN‐null cardiac muscle revealed reduced sarcolemma localization of many proteins with a known role in cardiomyopathy pathogenesis: dystrophin, the sarcoglycans (α‐, δ‐, and γ‐subunits), and β1D integrin. Transgenic overexpression of SSPN in Duchenne muscular dystrophy mice (mdxTG) improved cardiomyofiber cell adhesion, sarcolemma integrity, cardiac functional parameters, as well as increased expression of compensatory transmembrane proteins that mediate attachment to the extracellular matrix. Conclusions SSPN regulates sarcolemmal expression of laminin‐binding complexes that are critical to cardiac muscle function and protects against transient and chronic injury, including inherited cardiomyopathy.
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Affiliation(s)
- Michelle S Parvatiyar
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Jamie L Marshall
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Reginald T Nguyen
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.)
| | - Maria C Jordan
- Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA (M.C.J., K.P.R.)
| | - Vanitra A Richardson
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.)
| | - Kenneth P Roos
- Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Physiology, David Geffen School of Medicine, University of California, Los Angeles, CA (M.C.J., K.P.R.)
| | - Rachelle H Crosbie-Watson
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA (M.S.P., J.L.M., R.T.N., V.A.R., R.H.C.W.) Center for Duchenne Muscular Dystrophy, University of California, Los Angeles, CA (M.S.P., J.L.M., M.C.J., V.A.R., K.P.R., R.H.C.W.) Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA (R.H.C.W.)
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10
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Vander Heide RS. Mending a Broken Heart: The Role of Sarcospan in Duchenne Muscular Dystrophy-Associated Cardiomyopathy. J Am Heart Assoc 2015; 4:JAHA.115.002928. [PMID: 26702081 PMCID: PMC4845299 DOI: 10.1161/jaha.115.002928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Richard S Vander Heide
- Department of Pathology, Louisiana State University Health Science Center, New Orleans, LA (R.S.V.H.)
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11
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McGreevy JW, Hakim CH, McIntosh MA, Duan D. Animal models of Duchenne muscular dystrophy: from basic mechanisms to gene therapy. Dis Model Mech 2015; 8:195-213. [PMID: 25740330 PMCID: PMC4348559 DOI: 10.1242/dmm.018424] [Citation(s) in RCA: 316] [Impact Index Per Article: 35.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive muscle-wasting disorder. It is caused by loss-of-function mutations in the dystrophin gene. Currently, there is no cure. A highly promising therapeutic strategy is to replace or repair the defective dystrophin gene by gene therapy. Numerous animal models of DMD have been developed over the last 30 years, ranging from invertebrate to large mammalian models. mdx mice are the most commonly employed models in DMD research and have been used to lay the groundwork for DMD gene therapy. After ~30 years of development, the field has reached the stage at which the results in mdx mice can be validated and scaled-up in symptomatic large animals. The canine DMD (cDMD) model will be excellent for these studies. In this article, we review the animal models for DMD, the pros and cons of each model system, and the history and progress of preclinical DMD gene therapy research in the animal models. We also discuss the current and emerging challenges in this field and ways to address these challenges using animal models, in particular cDMD dogs.
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Affiliation(s)
- Joe W McGreevy
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
| | - Chady H Hakim
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
| | - Mark A McIntosh
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
| | - Dongsheng Duan
- Department of Molecular Microbiology and Immunology, School of Medicine, University of Missouri, Columbia, MO 65212, USA Department of Neurology, School of Medicine, University of Missouri, Columbia, MO 65212, USA
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12
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The dystroglycan: Nestled in an adhesome during embryonic development. Dev Biol 2015; 401:132-42. [DOI: 10.1016/j.ydbio.2014.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2014] [Revised: 06/23/2014] [Accepted: 07/08/2014] [Indexed: 01/11/2023]
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13
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Marshall JL, Oh J, Chou E, Lee JA, Holmberg J, Burkin DJ, Crosbie-Watson RH. Sarcospan integration into laminin-binding adhesion complexes that ameliorate muscular dystrophy requires utrophin and α7 integrin. Hum Mol Genet 2014; 24:2011-22. [PMID: 25504048 DOI: 10.1093/hmg/ddu615] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is caused by mutations in the dystrophin gene that result in loss of the dystrophin-glycoprotein complex, a laminin receptor that connects the myofiber to its surrounding extracellular matrix. Utrophin, a dystrophin ortholog that is normally localized to the neuromuscular junction, is naturally upregulated in DMD muscle, which partially compensates for the loss of dystrophin. Transgenic overexpression of utrophin causes broad sarcolemma localization of utrophin, restoration of laminin binding and amelioration of disease in the mdx mouse model of DMD. We previously demonstrated that overexpression of sarcospan, a dystrophin- and utrophin-binding protein, ameliorates mdx muscular dystrophy. Sarcospan boosts levels of utrophin to therapeutic levels at the sarcolemma, where attachment to laminin is restored. However, understanding the compensatory mechanism is complicated by concomitant upregulation of α7β1 integrin, which also binds laminin. Similar to the effects of utrophin, transgenic overexpression of α7 integrin prevents DMD disease in mice and is accompanied by increased abundance of utrophin around the extra-synaptic sarcolemma. In order to investigate the mechanisms underlying sarcospan 'rescue' of muscular dystrophy, we created double-knockout mice to test the contributions of utrophin or α7 integrin. We show that sarcospan-mediated amelioration of muscular dystrophy in DMD mice is dependent on the presence of both utrophin and α7β1 integrin, even when they are individually expressed at therapeutic levels. Furthermore, we found that association of sarcospan into laminin-binding complexes is dependent on utrophin and α7β1 integrin.
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Affiliation(s)
- Jamie L Marshall
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy
| | - Jennifer Oh
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy
| | - Eric Chou
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy
| | - Joy A Lee
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy
| | - Johan Holmberg
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy
| | - Dean J Burkin
- Department of Pharmacology, Center for Molecular Medicine, University of Nevada School of Medicine, Reno, NV 89557, USA
| | - Rachelle H Crosbie-Watson
- Department of Integrative Biology and Physiology, Center for Duchenne Muscular Dystrophy, Molecular Biology Institute, Department of Neurology, University of California, Los Angeles, CA 90095, USA and
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14
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Banks GB, Combs AC, Odom GL, Bloch RJ, Chamberlain JS. Muscle structure influences utrophin expression in mdx mice. PLoS Genet 2014; 10:e1004431. [PMID: 24922526 PMCID: PMC4055409 DOI: 10.1371/journal.pgen.1004431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/24/2014] [Indexed: 02/04/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder caused by mutations in the dystrophin gene. To examine the influence of muscle structure on the pathogenesis of DMD we generated mdx4cv:desmin double knockout (dko) mice. The dko male mice died of apparent cardiorespiratory failure at a median age of 76 days compared to 609 days for the desmin−/− mice. An ∼2.5 fold increase in utrophin expression in the dko skeletal muscles prevented necrosis in ∼91% of 1a, 2a and 2d/x fiber-types. In contrast, utrophin expression was reduced in the extrasynaptic sarcolemma of the dko fast 2b fibers leading to increased membrane fragility and dystrophic pathology. Despite lacking extrasynaptic utrophin, the dko fast 2b fibers were less dystrophic than the mdx4cv fast 2b fibers suggesting utrophin-independent mechanisms were also contributing to the reduced dystrophic pathology. We found no overt change in the regenerative capacity of muscle stem cells when comparing the wild-type, desmin−/−, mdx4cv and dko gastrocnemius muscles injured with notexin. Utrophin could form costameric striations with α-sarcomeric actin in the dko to maintain the integrity of the membrane, but the lack of restoration of the NODS (nNOS, α-dystrobrevin 1 and 2, α1-syntrophin) complex and desmin coincided with profound changes to the sarcomere alignment in the diaphragm, deposition of collagen between the myofibers, and impaired diaphragm function. We conclude that the dko mice may provide new insights into the structural mechanisms that influence endogenous utrophin expression that are pertinent for developing a therapy for DMD. Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder caused by mutations in the dystrophin gene. Utrophin is structurally similar to dystrophin and improving its expression can prevent skeletal muscle necrosis in the mdx mouse model of DMD. Consequently, improving utrophin expression is a primary therapeutic target for treating DMD. While the downstream mechanisms that influence utrophin expression and stability are well described, the upstream mechanisms are less clear. Here, we found that perturbing the highly ordered structure of striated muscle by genetically deleting desmin from mdx mice increased utrophin expression to levels that prevented skeletal muscle necrosis. Thus, the mdx:desmin double knockout mice may prove valuable in determining the upstream mechanisms that influence utrophin expression to develop a therapy for DMD.
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Affiliation(s)
- Glen B. Banks
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Ariana C. Combs
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Guy L. Odom
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jeffrey S. Chamberlain
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
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15
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Gawlik KI, Holmberg J, Durbeej M. Loss of dystrophin and β-sarcoglycan significantly exacerbates the phenotype of laminin α2 chain-deficient animals. THE AMERICAN JOURNAL OF PATHOLOGY 2014; 184:740-52. [PMID: 24393714 DOI: 10.1016/j.ajpath.2013.11.017] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Revised: 10/29/2013] [Accepted: 11/04/2013] [Indexed: 11/30/2022]
Abstract
The adhesion molecule laminin α2 chain interacts with the dystrophin-glycoprotein complex, contributes to normal muscle function, and protects skeletal muscles from damage. Complete loss of the laminin α2 chain in mice results in a severe muscular dystrophy phenotype and death at approximately 3 weeks of age. However, it is not clear if the remaining members of the dystrophin-glycoprotein complex further protect laminin α2 chain-deficient skeletal muscle fibers from degeneration. Hence, we generated mice deficient in laminin α2 chain and dystrophin (dy(3K)/mdx) and mice devoid of laminin α2 chain and β-sarcoglycan (dy(3K)/Sgcb). Severe muscular dystrophy and a lack of nourishment inevitably led to massive muscle wasting and death in double-knockout animals. The dy(3K)/Sgcb mice were generally more severely affected than dy(3K)/mdx mice. However, both double-knockout strains displayed exacerbated muscle degeneration, inflammation, fibrosis, and reduced life span (5 to 13 days) compared with single-knockout animals. However, neither extraocular nor cardiac muscle was affected in double-knockout animals. Our results suggest that, although laminin α2 chain, dystrophin, and β-sarcoglycan are all part of the same adhesion complex, they have complementary, but nonredundant, roles in maintaining sarcolemmal integrity and protecting skeletal muscle fibers from damage. Moreover, the double-knockout mice could potentially serve as models in which to study extremely aggressive muscle-wasting conditions.
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Affiliation(s)
- Kinga I Gawlik
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Johan Holmberg
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Madeleine Durbeej
- Muscle Biology Unit, Department of Experimental Medical Science, Lund University, Lund, Sweden.
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16
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Wyatt EJ, Sweeney HL, McNally EM. Meeting Report: New Directions in the Biology and Disease of Skeletal Muscle 2014. J Neuromuscul Dis 2014; 1:197-206. [PMID: 26207203 PMCID: PMC4508866 DOI: 10.3233/jnd-149003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The New Directions in the Biology and Disease of Skeletal Muscle is a scientific meeting, held every other year, with the stated purpose of bringing together scientists, clinicians, industry representatives and patient advocacy groups to disseminate new discovery useful for treatment inherited forms of neuromuscular disease, primarily the muscular dystrophies. This meeting originated as a response the Muscular Dystrophy Care Act in order to provide a venue for the free exchange of information, with the emphasis on unpublished or newly published data. Highlights of this years' meeting included results from early phase clinical trials for Duchenne Muscular Dystrophy, progress in understanding the epigenetic defects in Fascioscapulohumeral Muscular Dystrophy and new mechanisms of muscle membrane repair. The following is a brief report of the highlights from the conference.
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Affiliation(s)
- Eugene J Wyatt
- Department of Medicine, The University of Chicago, Chicago, IL USA
| | - H Lee Sweeney
- Department of Physiology, The University of Pennsylvania, Philadelphia, PA USA
| | - Elizabeth M McNally
- Department of Medicine, The University of Chicago, Chicago, IL USA ; Department of Human Genetics, The University of Chicago, Chicago, IL USA
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