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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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Helzer D, Kannan P, Reynolds JC, Gibbs DE, Crosbie RH. Role of microenvironment on muscle stem cell function in health, adaptation, and disease. Curr Top Dev Biol 2024; 158:179-201. [PMID: 38670705 DOI: 10.1016/bs.ctdb.2024.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/28/2024]
Abstract
The role of the cellular microenvironment has recently gained attention in the context of muscle health, adaption, and disease. Emerging evidence supports major roles for the extracellular matrix (ECM) in regeneration and the dynamic regulation of the satellite cell niche. Satellite cells normally reside in a quiescent state in healthy muscle, but upon muscle injury, they activate, proliferate, and fuse to the damaged fibers to restore muscle function and architecture. This chapter reviews the composition and mechanical properties of skeletal muscle ECM and the role of these factors in contributing to the satellite cell niche that impact muscle regeneration. In addition, the chapter details the effects of satellite cell-matrix interactions and provides evidence that there is bidirectional regulation affecting both the cellular and extracellular microenvironment within skeletal muscle. Lastly, emerging methods to investigate satellite cell-matrix interactions will be presented.
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Affiliation(s)
- Daniel Helzer
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Pranav Kannan
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joseph C Reynolds
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States
| | - Devin E Gibbs
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States
| | - Rachelle H Crosbie
- Department of Integrative Biology and Physiology, University of California, Los Angeles, Los Angeles, CA, United States; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, CA, United States; Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, University of California, Los Angeles, Los Angeles, CA, United States; Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, CA, United States.
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Hwang HS, Kahmini AR, Prascak J, Cejas-Carbonell A, Valera IC, Champion S, Corrigan M, Mumbi F, Parvatiyar MS. Sarcospan Deficiency Increases Oxidative Stress and Arrhythmias in Hearts after Acute Ischemia-Reperfusion Injury. Int J Mol Sci 2023; 24:11868. [PMID: 37511627 PMCID: PMC10380899 DOI: 10.3390/ijms241411868] [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: 05/27/2023] [Revised: 07/14/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
The protein sarcospan (SSPN) is an integral member of the dystrophin-glycoprotein complex (DGC) and has been shown to be important in the heart during the development and the response to acute stress. In this study, we investigated the role of SSPN in the cardiac response to acute ischemia-reperfusion (IR) injury in SSPN-deficient (SSPN-/-) mice. First, the hemodynamic response of SSPN-/- mice was tested and was similar to SSPN+/+ (wild-type) mice after isoproterenol injection. Using the in situ Langendorff perfusion method, SSPN-/- hearts were subjected to IR injury and found to have increased infarct size and arrhythmia susceptibility compared to SSPN+/+. Ca2+ handling was assessed in single cardiomyocytes and diastolic Ca2+ levels were increased after acute β-AR stimulation in SSPN+/+ but not SSPN-/-. It was also found that SSPN-/- cardiomyocytes had reduced Ca2+ SR content compared to SSPN+/+ but similar SR Ca2+ release. Next, we used qRT-PCR to examine gene expression of Ca2+ handling proteins after acute IR injury. SSPN-/- hearts showed a significant decrease in L-type Ca2+ channels and a significant increase in Ca2+ release channel (RyR2) expression. Interestingly, under oxidizing conditions reminiscent of IR, SSPN-/- cardiomyocytes, had increased H2O2-induced reactive oxygen species production compared to SSPN+/+. Examination of oxidative stress proteins indicated that NADPH oxidase 4 and oxidized CAMKII were increased in SSPN-/- hearts after acute IR injury. These results suggest that increased arrhythmia susceptibility in SSPN-/- hearts post-IR injury may arise from alterations in Ca2+ handling and a reduced capacity to regulate oxidative stress pathways.
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Affiliation(s)
- Hyun Seok Hwang
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Aida Rahimi Kahmini
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Julia Prascak
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Alexis Cejas-Carbonell
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Isela C Valera
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Samantha Champion
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Mikayla Corrigan
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Florence Mumbi
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Michelle S Parvatiyar
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
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Shivanna K, Astumian M, Raut P, Ngo VN, Hess ST, Henry C. Super-Resolution Imaging Reveals the Nanoscale Distributions of Dystroglycan and Integrin Itga7 in Zebrafish Muscle Fibers. Biomedicines 2023; 11:1941. [PMID: 37509580 PMCID: PMC10377463 DOI: 10.3390/biomedicines11071941] [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: 06/07/2023] [Revised: 06/30/2023] [Accepted: 07/06/2023] [Indexed: 07/30/2023] Open
Abstract
Cell signaling is determined partially by the localization and abundance of proteins. Dystroglycan and integrin are both transmembrane receptors that connect the cytoskeleton inside muscle cells to the extracellular matrix outside muscle cells, maintaining proper adhesion and function of muscle. The position and abundance of Dystroglycan relative to integrins is thought to be important for muscle adhesion and function. The subcellular localization and quantification of these receptor proteins can be determined at the nanometer scale by FPALM super-resolution microscopy. We used FPALM to determine localizations of Dystroglycan and integrin proteins in muscle fibers of intact zebrafish (Danio rerio). Results were consistent with confocal imaging data, but illuminate further details at the nanoscale and show the feasibility of using FPALM to quantify interactions of two proteins in a whole organism.
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Affiliation(s)
- Komala Shivanna
- Department of Physics & Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469-5709, USA; (K.S.); (P.R.); (V.-N.N.)
| | - Mary Astumian
- School of Biology and Ecology, University of Maine, 217 Hitchner Hall, Orono, ME 04469-5751, USA;
| | - Prakash Raut
- Department of Physics & Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469-5709, USA; (K.S.); (P.R.); (V.-N.N.)
| | - Vinh-Nhan Ngo
- Department of Physics & Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469-5709, USA; (K.S.); (P.R.); (V.-N.N.)
| | - Samuel T. Hess
- Department of Physics & Astronomy, University of Maine, 5709 Bennett Hall, Orono, ME 04469-5709, USA; (K.S.); (P.R.); (V.-N.N.)
| | - Clarissa Henry
- School of Biology and Ecology, University of Maine, 217 Hitchner Hall, Orono, ME 04469-5751, USA;
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Chen Z, Kelly JR, Morales JE, Sun RC, De A, Burkin DJ, McCarty JH. The alpha7 integrin subunit in astrocytes promotes endothelial blood-brain barrier integrity. Development 2023; 150:dev201356. [PMID: 36960827 PMCID: PMC10112902 DOI: 10.1242/dev.201356] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 02/22/2023] [Indexed: 03/25/2023]
Abstract
The blood-brain barrier (BBB) is a vascular endothelial cell boundary that partitions the circulation from the central nervous system to promote normal brain health. We have a limited understanding of how the BBB is formed during development and maintained in adulthood. We used quantitative transcriptional profiling to investigate whether specific adhesion molecules are involved in BBB functions, with an emphasis on understanding how astrocytes interact with endothelial cells. Our results reveal a striking enrichment of multiple genes encoding laminin subunits as well as the laminin receptor gene Itga7, which encodes the alpha7 integrin subunit, in astrocytes. Genetic ablation of Itga7 in mice led to aberrant BBB permeability and progressive neurological pathologies. Itga7-/- mice also showed a reduction in laminin protein expression in parenchymal basement membranes. Blood vessels in the Itga7-/- brain showed separation from surrounding astrocytes and had reduced expression of the tight junction proteins claudin 5 and ZO-1. We propose that the alpha7 integrin subunit in astrocytes via adhesion to laminins promotes endothelial cell junction integrity, all of which is required to properly form and maintain a functional BBB.
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Affiliation(s)
- Zhihua Chen
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Jack R. Kelly
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - John E. Morales
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Raymond C. Sun
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Arpan De
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Dean J. Burkin
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV 89557, USA
| | - Joseph H. McCarty
- Department of Neurosurgery, University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, 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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McCourt JL, Stearns-Reider KM, Mamsa H, Kannan P, Afsharinia MH, Shu C, Gibbs EM, Shin KM, Kurmangaliyev YZ, Schmitt LR, Hansen KC, Crosbie RH. Multi-omics analysis of sarcospan overexpression in mdx skeletal muscle reveals compensatory remodeling of cytoskeleton-matrix interactions that promote mechanotransduction pathways. Skelet Muscle 2023; 13:1. [PMID: 36609344 PMCID: PMC9817407 DOI: 10.1186/s13395-022-00311-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Accepted: 12/06/2022] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The dystrophin-glycoprotein complex (DGC) is a critical adhesion complex of the muscle cell membrane, providing a mechanical link between the extracellular matrix (ECM) and the cortical cytoskeleton that stabilizes the sarcolemma during repeated muscle contractions. One integral component of the DGC is the transmembrane protein, sarcospan (SSPN). Overexpression of SSPN in the skeletal muscle of mdx mice (murine model of DMD) restores muscle fiber attachment to the ECM in part through an associated increase in utrophin and integrin adhesion complexes at the cell membrane, protecting the muscle from contraction-induced injury. In this study, we utilized transcriptomic and ECM protein-optimized proteomics data sets from wild-type, mdx, and mdx transgenic (mdxTG) skeletal muscle tissues to identify pathways and proteins driving the compensatory action of SSPN overexpression. METHODS The tibialis anterior and quadriceps muscles were isolated from wild-type, mdx, and mdxTG mice and subjected to bulk RNA-Seq and global proteomics analysis using methods to enhance capture of ECM proteins. Data sets were further analyzed through the ingenuity pathway analysis (QIAGEN) and integrative gene set enrichment to identify candidate networks, signaling pathways, and upstream regulators. RESULTS Through our multi-omics approach, we identified 3 classes of differentially expressed genes and proteins in mdxTG muscle, including those that were (1) unrestored (significantly different from wild type, but not from mdx), (2) restored (significantly different from mdx, but not from wild type), and (3) compensatory (significantly different from both wild type and mdx). We identified signaling pathways that may contribute to the rescue phenotype, most notably cytoskeleton and ECM organization pathways. ECM-optimized proteomics revealed an increased abundance of collagens II, V, and XI, along with β-spectrin in mdxTG samples. Using ingenuity pathway analysis, we identified upstream regulators that are computationally predicted to drive compensatory changes, revealing a possible mechanism of SSPN rescue through a rewiring of cell-ECM bidirectional communication. We found that SSPN overexpression results in upregulation of key signaling molecules associated with regulation of cytoskeleton organization and mechanotransduction, including Yap1, Sox9, Rho, RAC, and Wnt. CONCLUSIONS Our findings indicate that SSPN overexpression rescues dystrophin deficiency partially through mechanotransduction signaling cascades mediated through components of the ECM and the cortical cytoskeleton.
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Affiliation(s)
- Jackie L. McCourt
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Kristen M. Stearns-Reider
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Orthopedic Surgery, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Hafsa Mamsa
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Pranav Kannan
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Mohammad Hossein Afsharinia
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Cynthia Shu
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Elizabeth M. Gibbs
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Kara M. Shin
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA
| | - Yerbol Z. Kurmangaliyev
- grid.19006.3e0000 0000 9632 6718Department of Biological Chemistry, Howard Hughes Medical Institute, David Geffen School of Medicine, University of California, Los Angeles, CA USA
| | - Lauren R. Schmitt
- grid.241116.10000000107903411Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, CO USA
| | - Kirk C. Hansen
- grid.241116.10000000107903411Department of Biochemistry and Molecular Genetics, University of Colorado, Denver, CO USA
| | - Rachelle H. Crosbie
- grid.19006.3e0000 0000 9632 6718Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095 USA ,grid.19006.3e0000 0000 9632 6718Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Molecular Biology Institute, University of California, Los Angeles, CA USA ,grid.19006.3e0000 0000 9632 6718Broad Stem Cell Research Center, University of California, Los Angeles, CA USA
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Gargan S, Dowling P, Zweyer M, Henry M, Meleady P, Swandulla D, Ohlendieck K. Proteomic Identification of Markers of Membrane Repair, Regeneration and Fibrosis in the Aged and Dystrophic Diaphragm. Life (Basel) 2022; 12:1679. [PMID: 36362832 PMCID: PMC9696191 DOI: 10.3390/life12111679] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/13/2022] [Accepted: 10/20/2022] [Indexed: 07/30/2023] Open
Abstract
Deficiency in the membrane cytoskeletal protein dystrophin is the underlying cause of the progressive muscle wasting disease named Duchenne muscular dystrophy. In order to detect novel disease marker candidates and confirm the complexity of the pathobiochemical signature of dystrophinopathy, mass spectrometric screening approaches represent ideal tools for comprehensive biomarker discovery studies. In this report, we describe the comparative proteomic analysis of young versus aged diaphragm muscles from wild type versus the dystrophic mdx-4cv mouse model of X-linked muscular dystrophy. The survey confirmed the drastic reduction of the dystrophin-glycoprotein complex in the mdx-4cv diaphragm muscle and concomitant age-dependent changes in key markers of muscular dystrophy, including proteins involved in cytoskeletal organization, metabolite transportation, the cellular stress response and excitation-contraction coupling. Importantly, proteomic markers of the regulation of membrane repair, tissue regeneration and reactive myofibrosis were detected by mass spectrometry and changes in key proteins were confirmed by immunoblotting. Potential disease marker candidates include various isoforms of annexin, the matricellular protein periostin and a large number of collagens. Alterations in these proteoforms can be useful to evaluate adaptive, compensatory and pathobiochemical changes in the intracellular cytoskeleton, myofiber membrane integrity and the extracellular matrix in dystrophin-deficient skeletal muscle tissues.
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Affiliation(s)
- Stephen Gargan
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Ireland
| | - Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Ireland
| | - Margit Zweyer
- Department of Neonatology and Paediatric Intensive Care, Children’s Hospital, German Center for Neurodegenerative Diseases, University of Bonn, D53127 Bonn, Germany
| | - Michael Henry
- National Institute for Cellular Biotechnology, Dublin City University, D09 E432 Dublin, Ireland
| | - Paula Meleady
- National Institute for Cellular Biotechnology, Dublin City University, D09 E432 Dublin, Ireland
| | - Dieter Swandulla
- Institute of Physiology, University of Bonn, D53115 Bonn, Germany
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, W23 F2H6 Maynooth, Ireland
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23 F2H6 Maynooth, Ireland
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Wu R, Song Y, Wu S, Chen Y. Promising therapeutic approaches of utrophin replacing dystrophin in the treatment of Duchenne muscular dystrophy. FUNDAMENTAL RESEARCH 2022. [DOI: 10.1016/j.fmre.2022.07.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022] Open
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10
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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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11
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Cellular pathology of the human heart in Duchenne muscular dystrophy (DMD): lessons learned from in vitro modeling. Pflugers Arch 2021; 473:1099-1115. [DOI: 10.1007/s00424-021-02589-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 05/24/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023]
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12
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Soblechero-Martín P, López-Martínez A, de la Puente-Ovejero L, Vallejo-Illarramendi A, Arechavala-Gomeza V. Utrophin modulator drugs as potential therapies for Duchenne and Becker muscular dystrophies. Neuropathol Appl Neurobiol 2021; 47:711-723. [PMID: 33999469 PMCID: PMC8518368 DOI: 10.1111/nan.12735] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 03/28/2021] [Accepted: 05/10/2021] [Indexed: 12/25/2022]
Abstract
Utrophin is an autosomal paralogue of dystrophin, a protein whose deficit causes Duchenne and Becker muscular dystrophies (DMD/BMD). Utrophin is naturally overexpressed at the sarcolemma of mature dystrophin‐deficient fibres in DMD and BMD patients as well as in the mdx Duchenne mouse model. Dystrophin and utrophin can co‐localise in human foetal muscle, in the dystrophin‐competent fibres from DMD/BMD carriers, and revertant fibre clusters in biopsies from DMD patients. These findings suggest that utrophin overexpression could act as a surrogate, compensating for the lack of dystrophin, and, as such, it could be used in combination with dystrophin restoration therapies. Different strategies to overexpress utrophin are currently under investigation. In recent years, many compounds have been reported to modulate utrophin expression efficiently in preclinical studies and ameliorate the dystrophic phenotype in animal models of the disease. In this manuscript, we discuss the current knowledge on utrophin protein and the different mechanisms that modulate its expression in skeletal muscle. We also include a comprehensive review of compounds proposed as utrophin regulators and, as such, potential therapeutic candidates for these muscular dystrophies.
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Affiliation(s)
- Patricia Soblechero-Martín
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Clinical Laboratory Service, Osakidetza Basque Health Service, Bilbao-Basurto Integrated Health Organisation, Basurto University Hospital, Bilbao, Spain
| | - Andrea López-Martínez
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain
| | | | | | - Virginia Arechavala-Gomeza
- Neuromuscular Disorders, Biocruces Bizkaia Health Research Institute, Barakaldo, Spain.,Ikerbasque, Basque Foundation for Science, Bilbao, Spain
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13
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Valera IC, Wacker AL, Hwang HS, Holmes C, Laitano O, Landstrom AP, Parvatiyar MS. Essential roles of the dystrophin-glycoprotein complex in different cardiac pathologies. Adv Med Sci 2021; 66:52-71. [PMID: 33387942 DOI: 10.1016/j.advms.2020.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 12/12/2020] [Accepted: 12/17/2020] [Indexed: 12/20/2022]
Abstract
The dystrophin-glycoprotein complex (DGC), situated at the sarcolemma dynamically remodels during cardiac disease. This review examines DGC remodeling as a common denominator in diseases affecting heart function and health. Dystrophin and the DGC serve as broad cytoskeletal integrators that are critical for maintaining stability of muscle membranes. The presence of pathogenic variants in genes encoding proteins of the DGC can cause absence of the protein and/or alterations in other complex members leading to muscular dystrophies. Targeted studies have allowed the individual functions of affected proteins to be defined. The DGC has demonstrated its dynamic function, remodeling under a number of conditions that stress the heart. Beyond genetic causes, pathogenic processes also impinge on the DGC, causing alterations in the abundance of dystrophin and associated proteins during cardiac insult such as ischemia-reperfusion injury, mechanical unloading, and myocarditis. When considering new therapeutic strategies, it is important to assess DGC remodeling as a common factor in various heart diseases. The DGC connects the internal F-actin-based cytoskeleton to laminin-211 of the extracellular space, playing an important role in the transmission of mechanical force to the extracellular matrix. The essential functions of dystrophin and the DGC have been long recognized. DGC based therapeutic approaches have been primarily focused on muscular dystrophies, however it may be a beneficial target in a number of disorders that affect the heart. This review provides an account of what we now know, and discusses how this knowledge can benefit persistent health conditions in the clinic.
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Affiliation(s)
- Isela C Valera
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Amanda L Wacker
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Hyun Seok Hwang
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Christina Holmes
- Department of Chemical and Biomedical Engineering, Florida A&M University-Florida State University College of Engineering, Tallahassee, FL, USA
| | - Orlando Laitano
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology, Duke University School of Medicine, Durham, NC, USA; Department of Cell Biology, Duke University School of Medicine, Durham, NC, USA
| | - Michelle S Parvatiyar
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA.
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14
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Dowling P, Gargan S, Murphy S, Zweyer M, Sabir H, Swandulla D, Ohlendieck K. The Dystrophin Node as Integrator of Cytoskeletal Organization, Lateral Force Transmission, Fiber Stability and Cellular Signaling in Skeletal Muscle. Proteomes 2021; 9:9. [PMID: 33540575 PMCID: PMC7931087 DOI: 10.3390/proteomes9010009] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/22/2021] [Accepted: 01/27/2021] [Indexed: 12/13/2022] Open
Abstract
The systematic bioanalytical characterization of the protein product of the DMD gene, which is defective in the pediatric disorder Duchenne muscular dystrophy, led to the discovery of the membrane cytoskeletal protein dystrophin. Its full-length muscle isoform Dp427-M is tightly linked to a sarcolemma-associated complex consisting of dystroglycans, sarcoglyans, sarcospan, dystrobrevins and syntrophins. Besides these core members of the dystrophin-glycoprotein complex, the wider dystrophin-associated network includes key proteins belonging to the intracellular cytoskeleton and microtubular assembly, the basal lamina and extracellular matrix, various plasma membrane proteins and cytosolic components. Here, we review the central role of the dystrophin complex as a master node in muscle fibers that integrates cytoskeletal organization and cellular signaling at the muscle periphery, as well as providing sarcolemmal stabilization and contractile force transmission to the extracellular region. The combination of optimized tissue extraction, subcellular fractionation, advanced protein co-purification strategies, immunoprecipitation, liquid chromatography and two-dimensional gel electrophoresis with modern mass spectrometry-based proteomics has confirmed the composition of the core dystrophin complex at the sarcolemma membrane. Importantly, these biochemical and mass spectrometric surveys have identified additional members of the wider dystrophin network including biglycan, cavin, synemin, desmoglein, tubulin, plakoglobin, cytokeratin and a variety of signaling proteins and ion channels.
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Affiliation(s)
- Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, W23F2H6 Maynooth, Co. Kildare, Ireland; (P.D.); (S.G.)
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23F2H6 Maynooth, Co. Kildare, Ireland
| | - Stephen Gargan
- Department of Biology, Maynooth University, National University of Ireland, W23F2H6 Maynooth, Co. Kildare, Ireland; (P.D.); (S.G.)
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23F2H6 Maynooth, Co. Kildare, Ireland
| | - Sandra Murphy
- Newcastle Fibrosis Research Group, Newcastle University Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne NE24HH, UK;
| | - Margit Zweyer
- Department of Neonatology and Paediatric Intensive Care, Children’s Hospital, University of Bonn, D53113 Bonn, Germany; (M.Z.); (H.S.)
| | - Hemmen Sabir
- Department of Neonatology and Paediatric Intensive Care, Children’s Hospital, University of Bonn, D53113 Bonn, Germany; (M.Z.); (H.S.)
| | - Dieter Swandulla
- Institute of Physiology II, University of Bonn, D53115 Bonn, Germany;
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, W23F2H6 Maynooth, Co. Kildare, Ireland; (P.D.); (S.G.)
- Kathleen Lonsdale Institute for Human Health Research, Maynooth University, W23F2H6 Maynooth, Co. Kildare, Ireland
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15
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Gibbs EM, McCourt JL, Shin KM, Hammond KG, Marshall JL, Crosbie RH. Loss of sarcospan exacerbates pathology in mdx mice, but does not affect utrophin amelioration of disease. Hum Mol Genet 2021; 30:149-159. [PMID: 33432327 PMCID: PMC8091037 DOI: 10.1093/hmg/ddaa264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 10/26/2020] [Accepted: 11/30/2020] [Indexed: 01/02/2023] Open
Abstract
The dystrophin-glycoprotein complex (DGC) is a membrane adhesion complex that provides structural stability at the sarcolemma by linking the myocyte's internal cytoskeleton and external extracellular matrix. In Duchenne muscular dystrophy (DMD), the absence of dystrophin leads to the loss of the DGC at the sarcolemma, resulting in sarcolemmal instability and progressive muscle damage. Utrophin (UTRN), an autosomal homolog of dystrophin, is upregulated in dystrophic muscle and partially compensates for the loss of dystrophin in muscle from patients with DMD. Here, we examine the interaction between Utr and sarcospan (SSPN), a small transmembrane protein that is a core component of both UTRN-glycoprotein complex (UGC) and DGC. We show that additional loss of SSPN causes an earlier onset of disease in dystrophin-deficient mdx mice by reducing the expression of the UGC at the sarcolemma. In order to further evaluate the role of SSPN in maintaining therapeutic levels of Utr at the sarcolemma, we tested the effect of Utr transgenic overexpression in mdx mice lacking SSPN (mdx:SSPN -/-:Utr-Tg). We found that overexpression of Utr restored SSPN to the sarcolemma in mdx muscle but that the ablation of SSPN in mdx muscle reduced Utr at the membrane. Nevertheless, Utr overexpression reduced central nucleation and improved grip strength in both lines. These findings demonstrate that high levels of Utr transgenic overexpression ameliorate the mdx phenotype independently of SSPN expression but that loss of SSPN may impair Utr-based mechanisms that rely on lower levels of Utr protein.
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Affiliation(s)
- Elizabeth M Gibbs
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Jackie L McCourt
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Kara M Shin
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Katherine G Hammond
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Jamie L Marshall
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA
| | - Rachelle H Crosbie
- Department of Integrative Biology and Physiology, University of California, Los Angeles, CA 90095, USA.,Department of Neurology, David Geffen School of Medicine, University of California, Los Angeles, CA 90095, USA.,Molecular Biology Institute, University of California, Los Angeles, CA, USA
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16
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Lambert MR, Spinazzola JM, Widrick JJ, Pakula A, Conner JR, Chin JE, Owens JM, Kunkel LM. PDE10A Inhibition Reduces the Manifestation of Pathology in DMD Zebrafish and Represses the Genetic Modifier PITPNA. Mol Ther 2020; 29:1086-1101. [PMID: 33221436 PMCID: PMC7934586 DOI: 10.1016/j.ymthe.2020.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 11/04/2020] [Accepted: 11/15/2020] [Indexed: 12/25/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe genetic disorder caused by mutations in the DMD gene. Absence of dystrophin protein leads to progressive degradation of skeletal and cardiac function and leads to premature death. Over the years, zebrafish have been increasingly used for studying DMD and are a powerful tool for drug discovery and therapeutic development. In our study, a birefringence screening assay led to identification of phosphodiesterase 10A (PDE10A) inhibitors that reduced the manifestation of dystrophic muscle phenotype in dystrophin-deficient sapje-like zebrafish larvae. PDE10A has been validated as a therapeutic target by pde10a morpholino-mediated reduction in muscle pathology and improvement in locomotion, muscle, and vascular function as well as long-term survival in sapje-like larvae. PDE10A inhibition in zebrafish and DMD patient-derived myoblasts were also associated with reduction of PITPNA expression that has been previously identified as a protective genetic modifier in two exceptional dystrophin-deficient golden retriever muscular dystrophy (GRMD) dogs that escaped the dystrophic phenotype. The combination of a phenotypic assay and relevant functional assessments in the sapje-like zebrafish enhances the potential for the prospective discovery of DMD therapeutics. Indeed, our results suggest a new application for a PDE10A inhibitor as a potential DMD therapeutic to be investigated in a mouse model of DMD.
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Affiliation(s)
- Matthias R Lambert
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Janelle M Spinazzola
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Jeffrey J Widrick
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Anna Pakula
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - James R Conner
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Janice E Chin
- Rare Disease Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Jane M Owens
- Rare Disease Research Unit, Pfizer, Cambridge, MA 02139, USA
| | - Louis M Kunkel
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; The Stem Cell Program, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA; The Manton Center for Orphan Disease Research at Boston Children's Hospital, Boston, MA 02115, USA.
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17
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Shu C, Parfenova L, Mokhonova E, Collado JR, Damoiseaux R, Campagna J, John V, Crosbie RH. High-throughput screening identifies modulators of sarcospan that stabilize muscle cells and exhibit activity in the mouse model of Duchenne muscular dystrophy. Skelet Muscle 2020; 10:26. [PMID: 32948250 PMCID: PMC7499884 DOI: 10.1186/s13395-020-00244-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Accepted: 09/01/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Duchenne muscular dystrophy (DMD) is a degenerative muscle disease caused by mutations in the dystrophin gene. Loss of dystrophin prevents the formation of a critical connection between the muscle cell membrane and the extracellular matrix. Overexpression of sarcospan (SSPN) in the mouse model of DMD restores the membrane connection and reduces disease severity, making SSPN a promising therapeutic target for pharmacological upregulation. METHODS Using a previously described cell-based promoter reporter assay of SSPN gene expression (hSSPN-EGFP), we conducted high-throughput screening on libraries of over 200,000 curated small molecules to identify SSPN modulators. The hits were validated in both hSSPN-EGFP and hSSPN-luciferase reporter cells. Hit selection was conducted on dystrophin-deficient mouse and human myotubes with assessments of (1) SSPN gene expression using quantitative PCR and (2) SSPN protein expression using immunoblotting and an ELISA. A membrane stability assay using osmotic shock was used to validate the functional effects of treatment followed by cell surface biotinylation to label cell surface proteins. Dystrophin-deficient mdx mice were treated with compound, and muscle was subjected to quantitative PCR to assess SSPN gene expression. RESULTS We identified and validated lead compounds that increased SSPN gene and protein expression in dystrophin-deficient mouse and human muscle cells. The lead compound OT-9 increased cell membrane localization of compensatory laminin-binding adhesion complexes and improved membrane stability in DMD myotubes. We demonstrated that the membrane stabilizing benefit is dependent on SSPN. Intramuscular injection of OT-9 in the mouse model of DMD increased SSPN gene expression. CONCLUSIONS This study identifies a pharmacological approach to treat DMD and sets the path for the development of SSPN-based therapies.
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Affiliation(s)
- Cynthia Shu
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 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, CA, USA
| | - Liubov Parfenova
- 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
| | - Ekaterina Mokhonova
- 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, CA, 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, CA, USA
- California NanoSystems Institute, University of California Los Angeles, Los Angeles, CA, USA
| | - Jesus Campagna
- 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
- Drug Discovery Lab, University of California Los Angeles, Los Angeles, CA, USA
| | - Varghese John
- 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
- Drug Discovery Lab, University of California Los Angeles, Los Angeles, CA, USA
| | - Rachelle H Crosbie
- Molecular Biology Institute, University of California Los Angeles, Los Angeles, CA, 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, CA, 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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18
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Barraza-Flores P, Fontelonga TM, Wuebbles RD, Hermann HJ, Nunes AM, Kornegay JN, Burkin DJ. Laminin-111 protein therapy enhances muscle regeneration and repair in the GRMD dog model of Duchenne muscular dystrophy. Hum Mol Genet 2020; 28:2686-2695. [PMID: 31179490 DOI: 10.1093/hmg/ddz086] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 03/22/2019] [Accepted: 04/15/2019] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating X-linked disease affecting ~1 in 5000 males. DMD patients exhibit progressive muscle degeneration and weakness, leading to loss of ambulation and premature death from cardiopulmonary failure. We previously reported that mouse Laminin-111 (msLam-111) protein could reduce muscle pathology and improve muscle function in the mdx mouse model for DMD. In this study, we examined the ability of msLam-111 to prevent muscle disease progression in the golden retriever muscular dystrophy (GRMD) dog model of DMD. The msLam-111 protein was injected into the cranial tibial muscle compartment of GRMD dogs and muscle strength and pathology were assessed. The results showed that msLam-111 treatment increased muscle fiber regeneration and repair with improved muscle strength and reduced muscle fibrosis in the GRMD model. Together, these findings support the idea that Laminin-111 could serve as a novel protein therapy for the treatment of DMD.
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Affiliation(s)
- Pamela Barraza-Flores
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Tatiana M Fontelonga
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Ryan D Wuebbles
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Hailey J Hermann
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Andreia M Nunes
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
| | - Joe N Kornegay
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, USA
| | - Dean J Burkin
- Department of Pharmacology, University of Nevada, Reno School of Medicine, Reno, NV, USA
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19
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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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20
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Parvatiyar MS, Brownstein AJ, Kanashiro-Takeuchi RM, Collado JR, Dieseldorff Jones KM, Gopal J, Hammond KG, Marshall JL, Ferrel A, Beedle AM, Chamberlain JS, Renato Pinto J, Crosbie RH. Stabilization of the cardiac sarcolemma by sarcospan rescues DMD-associated cardiomyopathy. JCI Insight 2019; 5:123855. [PMID: 31039133 PMCID: PMC6629091 DOI: 10.1172/jci.insight.123855] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 04/23/2019] [Indexed: 02/02/2023] Open
Abstract
In the current preclinical study, we demonstrate the therapeutic potential of sarcospan (SSPN) overexpression to alleviate cardiomyopathy associated with Duchenne muscular dystrophy (DMD) utilizing dystrophin-deficient mdx mice with utrophin haploinsufficiency that more accurately represent the severe disease course of human DMD. SSPN interacts with dystrophin, the DMD disease gene product, and its autosomal paralog utrophin, which is upregulated in DMD as a partial compensatory mechanism. SSPN transgenic mice have enhanced abundance of fully glycosylated α-dystroglycan, which may further protect dystrophin-deficient cardiac membranes. Baseline echocardiography reveals SSPN improves systolic function and hypertrophic indices in mdx and mdx:utr-heterozygous mice. Assessment of SSPN transgenic mdx mice by hemodynamic pressure-volume methods highlights enhanced systolic performance compared to mdx controls. SSPN restores cardiac sarcolemma stability, the primary defect in DMD disease, reduces fibrotic response and improves contractile function. We demonstrate that SSPN ameliorates more advanced cardiac disease in the context of diminished sarcolemma expression of utrophin and β1D integrin that mitigate disease severity and partially restores responsiveness to β-adrenergic stimulation. Overall, our current and previous findings suggest SSPN overexpression in DMD mouse models positively impacts skeletal, pulmonary and cardiac performance by addressing the stability of proteins at the sarcolemma that protect the heart from injury, supporting SSPN and membrane stabilization as a therapeutic target for DMD.
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Affiliation(s)
- Michelle S. Parvatiyar
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Alexandra J. Brownstein
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Rosemeire M. Kanashiro-Takeuchi
- Interdisciplinary Stem Cell Institute, University of Miami, Florida, USA
- Department of Molecular and Cellular Pharmacology, University of Miami Miller School of Medicine, Miami, Florida, USA
| | | | | | - Jay Gopal
- Department of Integrative Biology & Physiology and
| | - Katherine G. Hammond
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Jamie L. Marshall
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
| | - Abel Ferrel
- Department of Integrative Biology & Physiology and
| | - Aaron M. Beedle
- Department of Pharmaceutical Sciences, Binghamton University State University of New York, Binghamton, New York, USA
| | | | - Jose Renato Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, Florida, USA
| | - Rachelle H. Crosbie
- Department of Integrative Biology & Physiology and
- Center for Duchenne Muscular Dystrophy, UCLA, Los Angeles, California, USA
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
- Molecular Biology Institute, UCLA, Los Angeles, California, USA
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21
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Keller M, Klös M, Rohde K, Krüger J, Kurze T, Dietrich A, Schön MR, Gärtner D, Lohmann T, Dreßler M, Stumvoll M, Blüher M, Kovacs P, Böttcher Y. DNA methylation of SSPN is linked to adipose tissue distribution and glucose metabolism. FASEB J 2018; 32:fj201800528R. [PMID: 29932866 DOI: 10.1096/fj.201800528r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
DNA methylation is a crucial epigenetic mechanism in obesity and fat distribution. We explored the Sarcospan ( SSPN) gene locus by using genome-wide data sets comprising methylation and expression data, pyrosequencing analysis in the promoter region, and genetic analysis of an SNP variant rs718314, which was previously reported to associate with waist-to-hip ratio. We found that DNA methylation influences several clinical variables related to fat distribution and glucose metabolism, while SSPN mRNA levels showed directionally opposite effects on these traits. Complete DNA methylation of the SSPN promoter construct suppressed the gene expression of firefly luciferase in MCF7 cells. Moreover, rs718314 was associated with waist and with DNA methylation at CpG sites. Our data strongly support the role of the SSPN locus in body fat composition and glucose homeostasis, and suggest that this is most likely the result of changes in DNA methylation of SSPN in adipose tissue.-Keller, M., Klös, M., Rohde, K., Krüger, J., Kurze, T., Dietrich, A., Schön, M. R., Gärtner, D., Lohmann, T., Dreßler, M., Stumvoll, M., Blüher, M., Kovacs, P., Böttcher, Y. DNA methylation of SSPN is linked to adipose tissue distribution and glucose metabolism.
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Affiliation(s)
- Maria Keller
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
- Genetic and Molecular Epidemiology Unit, Department of Clinical Sciences, Lund University Diabetes Centre, Skåne University Hospital, Malmö, Sweden
| | - Matthias Klös
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
- Department of Environmental Immunology, Helmholtz Centre for Environmental Research (UFZ), Leipzig, Germany
| | - Kerstin Rohde
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
- Institute of Clinical Medicine, Akershus University Hospital, University of Oslo, Lørenskog, Norway
| | | | - Tabea Kurze
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
| | - Arne Dietrich
- Department of Surgery, University of Leipzig, Leipzig, Germany
| | - Michael R Schön
- Städtisches Klinikum Karlsruhe, Clinic of Visceral Surgery, Karlsruhe, Germany; and
| | - Daniel Gärtner
- Städtisches Klinikum Karlsruhe, Clinic of Visceral Surgery, Karlsruhe, Germany; and
| | | | | | | | - Matthias Blüher
- Department of Medicine, University of Leipzig, Leipzig, Germany
| | - Peter Kovacs
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
| | - Yvonne Böttcher
- Integrated Research and Treatment Center (IFB) Adiposity Diseases, University of Leipzig, Leipzig, Germany
- Institute of Clinical Medicine, Akershus University Hospital, University of Oslo, Lørenskog, Norway
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22
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Hightower RM, Alexander MS. Genetic modifiers of Duchenne and facioscapulohumeral muscular dystrophies. Muscle Nerve 2018; 57:6-15. [PMID: 28877560 PMCID: PMC5759757 DOI: 10.1002/mus.25953] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2017] [Indexed: 01/05/2023]
Abstract
Muscular dystrophy is defined as the progressive wasting of skeletal muscles that is caused by inherited or spontaneous genetic mutations. Next-generation sequencing has greatly improved the accuracy and speed of diagnosis for different types of muscular dystrophy. Advancements in depth of coverage, convenience, and overall reduced cost have led to the identification of genetic modifiers that are responsible for phenotypic variability in affected patients. These genetic modifiers have been postulated to explain key differences in disease phenotypes, including age of loss of ambulation, steroid responsiveness, and the presence or absence of cardiac defects in patients with the same form of muscular dystrophy. This review highlights recent findings on genetic modifiers of Duchenne and facioscapulohumeral muscular dystrophies based on animal and clinical studies. These genetic modifiers hold great promise to be developed into novel therapeutic targets for the treatment of muscular dystrophies. Muscle Nerve 57: 6-15, 2018.
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Affiliation(s)
- Rylie M. Hightower
- University of Alabama at Birmingham Graduate School of Biomedical Sciences, Birmingham, AL 35294
| | - Matthew S. Alexander
- Department of Pediatrics, Division of Neurology at Children’s of Alabama and the University of Alabama at Birmingham, Birmingham, AL, 35294
- Department of Genetics, the University of Alabama at Birmingham, Birmingham, AL, 35294
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23
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Ponnusamy S, Sullivan RD, You D, Zafar N, He Yang C, Thiyagarajan T, Johnson DL, Barrett ML, Koehler NJ, Star M, Stephenson EJ, Bridges D, Cormier SA, Pfeffer LM, Narayanan R. Androgen receptor agonists increase lean mass, improve cardiopulmonary functions and extend survival in preclinical models of Duchenne muscular dystrophy. Hum Mol Genet 2017; 26:2526-2540. [PMID: 28453658 DOI: 10.1093/hmg/ddx150] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Accepted: 04/18/2017] [Indexed: 12/18/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a neuromuscular disease that predominantly affects boys as a result of mutation(s) in the dystrophin gene. DMD is characterized by musculoskeletal and cardiopulmonary complications, resulting in shorter life-span. Boys afflicted by DMD typically exhibit symptoms within 3-5 years of age and declining physical functions before attaining puberty. We hypothesized that rapidly deteriorating health of pre-pubertal boys with DMD could be due to diminished anabolic actions of androgens in muscle, and that intervention with an androgen receptor (AR) agonist will reverse musculoskeletal complications and extend survival. While castration of dystrophin and utrophin double mutant (mdx-dm) mice to mimic pre-pubertal nadir androgen condition resulted in premature death, maintenance of androgen levels extended the survival. Non-steroidal selective-AR modulator, GTx-026, which selectively builds muscle and bone was tested in X-linked muscular dystrophy mice (mdx). GTx-026 significantly increased body weight, lean mass and grip strength by 60-80% over vehicle-treated mdx mice. While vehicle-treated castrated mdx mice exhibited cardiopulmonary impairment and fibrosis of heart and lungs, GTx-026 returned cardiopulmonary function and intensity of fibrosis to healthy control levels. GTx-026 elicits its musculoskeletal effects through pathways that are distinct from dystrophin-regulated pathways, making AR agonists ideal candidates for combination approaches. While castration of mdx-dm mice resulted in weaker muscle and shorter survival, GTx-026 treatment increased the muscle mass, function and survival, indicating that androgens are important for extended survival. These preclinical results support the importance of androgens and the need for intervention with AR agonists to treat DMD-affected boys.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Erin J Stephenson
- Department of Pediatrics.,Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Dave Bridges
- Department of Pediatrics.,Department of Physiology, University of Tennessee Health Science Center, Memphis, TN, USA
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24
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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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25
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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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26
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Holland A, Murphy S, Dowling P, Ohlendieck K. Pathoproteomic profiling of the skeletal muscle matrisome in dystrophinopathy associated myofibrosis. Proteomics 2015; 16:345-66. [PMID: 26256116 DOI: 10.1002/pmic.201500158] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/12/2015] [Accepted: 07/24/2015] [Indexed: 12/14/2022]
Abstract
The gradual accumulation of collagen and associated proteins of the extracellular matrix is a crucial myopathological parameter of many neuromuscular disorders. Progressive tissue damage and fibrosis play a key pathobiochemical role in the dysregulation of contractile functions and often correlates with poor motor outcome in muscular dystrophies. Following a brief introduction into the role of the extracellular matrix in skeletal muscles, we review here the proteomic profiling of myofibrosis and its intrinsic role in X-linked muscular dystrophy. Although Duchenne muscular dystrophy is primarily a disease of the membrane cytoskeleton, one of its most striking histopathological features is a hyperactive connective tissue and tissue scarring. We outline the identification of novel factors involved in the modulation of the extracellular matrix in muscular dystrophy, such as matricellular proteins. The establishment of novel proteomic markers will be helpful in improving the diagnosis, prognosis, and therapy monitoring in relation to fibrotic substitution of contractile tissue. In the future, the prevention of fibrosis will be crucial for providing optimum conditions to apply novel pharmacological treatments, as well as establish cell-based approaches or gene therapeutic interventions. The elimination of secondary abnormalities in the matrisome promises to reduce tissue scarring and the loss of skeletal muscle elasticity.
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Affiliation(s)
- Ashling Holland
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Sandra Murphy
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Paul Dowling
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland
| | - Kay Ohlendieck
- Department of Biology, Maynooth University, National University of Ireland, Maynooth, Co. Kildare, Ireland
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