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Tapia G, Fuenzalida S, Rivera C, Apablaza P, Silva M, Jaimovich E, Juretić N. L-Arginine Activates the Neuregulin-1/ErbB Receptor Signaling Pathway and Increases Utrophin mRNA Levels in C2C12 Cells. Biochem Res Int 2025; 2025:2171745. [PMID: 40224962 PMCID: PMC11991828 DOI: 10.1155/bri/2171745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 01/31/2025] [Accepted: 02/03/2025] [Indexed: 04/15/2025] Open
Abstract
L-arginine induces the expression of utrophin in skeletal muscle cells, so it has been proposed as a pharmacological treatment to attenuate the symptoms of Duchenne muscular dystrophy (DMD). On the other hand, it has been described that one of the pathways that participates in the expression of utrophin in muscle is the Neuregulin-1 (NRG-1)/ErbB receptors pathway. Several studies have postulated that disintegrin and metalloprotease-17 (ADAM17) causes the proteolytic processing of NRG of transmembrane, allowing the release of NRG to the medium, which when joining its ErbB receptor activates the signaling pathway that triggers utrophin transcription. The aim of this study was to evaluate the effect of L-arginine in the activation of NRG-1/ErbB pathway and utrophin mRNA levels in C2C12 cells, and the participation of ADAM17 in this process. Our results indicate that L-arginine induces phosphorylation of ErbB2 and increases utrophin mRNA levels in C2C12 myotubes, with a maximum increase of 2-fold at 4 h post-stimulation. This effect is not observed when the myotubes are stimulated in the presence of GM6001 (general metalloprotease inhibitor) or PD-158780 (specific inhibitor of ErbB receptor phosphorylation). Experiments performed by flow cytometry suggest that L-arginine stimulates ADAM17 activation in our study model. Furthermore, immunofluorescence analysis supports our findings that L-arginine stimulates ADAM17 increase in treated myotubes. However, our results using pharmacological inhibitors suggest that ADAM17 does not participate in utrophin expression in C2C12 cells treated with L-arginine. The results obtained help to clarify the mechanism of action of L-arginine in the expression of utrophin in muscle cells, which will contribute to the design of new therapeutic strategies in pathologies such as DMD.
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Affiliation(s)
- Gladys Tapia
- Programa de Farmacología Molecular y Clínica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Sebastián Fuenzalida
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Constanza Rivera
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Pía Apablaza
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Mónica Silva
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Enrique Jaimovich
- Centro de Estudios de Ejercicio, Metabolismo y Cáncer, Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
| | - Nevenka Juretić
- Programa de Biología Celular y Molecular, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Santiago 8380000, Chile
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2
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Ham AS, Lin S, Tse A, Thürkauf M, McGowan TJ, Jörin L, Oliveri F, Rüegg MA. Single-nuclei sequencing of skeletal muscle reveals subsynaptic-specific transcripts involved in neuromuscular junction maintenance. Nat Commun 2025; 16:2220. [PMID: 40044687 PMCID: PMC11882927 DOI: 10.1038/s41467-025-57487-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2024] [Accepted: 02/13/2025] [Indexed: 03/09/2025] Open
Abstract
The neuromuscular junction (NMJ) is the synapse formed between motor neurons and skeletal muscle fibers. Its stability relies on the continued expression of genes in a subset of myonuclei, called NMJ myonuclei. Here, we use single-nuclei RNA-sequencing (snRNA-seq) to identify numerous NMJ-specific transcripts. To elucidate how the NMJ transcriptome is regulated, we also performed snRNA-seq on sciatic nerve transected, botulinum toxin injected, and Musk knockout muscles. The data show that NMJ gene expression is not only driven by agrin-Lrp4/MuSK signaling but is also affected by electrical activity and trophic factors other than agrin. By selecting the three NMJ genes Etv4, Lrtm1, and Pdzrn4, we further characterize novel contributors to NMJ stability and function. AAV-mediated overexpression shows that Etv4 is sufficient to upregulate the expression of -50% of the NMJ genes in non-synaptic myonuclei, while AAV-CRISPR/Cas9-mediated muscle-specific knockout of Pdzrn4 induces NMJ fragmentation. Further investigation of Pdzrn4 revealed that it localizes to the Golgi apparatus and interacts with MuSK protein. Collectively, our data provide a rich resource of NMJ transcripts, highlight the importance of ETS transcription factors at the NMJ, and suggest a novel pathway for NMJ post-translational modifications.
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Affiliation(s)
| | - Shuo Lin
- Biozentrum, University of Basel, Basel, Switzerland
| | - Alice Tse
- Biozentrum, University of Basel, Basel, Switzerland
| | | | | | - Lena Jörin
- Biozentrum, University of Basel, Basel, Switzerland
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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: 21] [Impact Index Per Article: 5.3] [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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4
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Rodríguez Cruz PM, Cossins J, Beeson D, Vincent A. The Neuromuscular Junction in Health and Disease: Molecular Mechanisms Governing Synaptic Formation and Homeostasis. Front Mol Neurosci 2020; 13:610964. [PMID: 33343299 PMCID: PMC7744297 DOI: 10.3389/fnmol.2020.610964] [Citation(s) in RCA: 118] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 10/30/2020] [Indexed: 12/28/2022] Open
Abstract
The neuromuscular junction (NMJ) is a highly specialized synapse between a motor neuron nerve terminal and its muscle fiber that are responsible for converting electrical impulses generated by the motor neuron into electrical activity in the muscle fibers. On arrival of the motor nerve action potential, calcium enters the presynaptic terminal, which leads to the release of the neurotransmitter acetylcholine (ACh). ACh crosses the synaptic gap and binds to ACh receptors (AChRs) tightly clustered on the surface of the muscle fiber; this leads to the endplate potential which initiates the muscle action potential that results in muscle contraction. This is a simplified version of the events in neuromuscular transmission that take place within milliseconds, and are dependent on a tiny but highly structured NMJ. Much of this review is devoted to describing in more detail the development, maturation, maintenance and regeneration of the NMJ, but first we describe briefly the most important molecules involved and the conditions that affect their numbers and function. Most important clinically worldwide, are myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS) and congenital myasthenic syndromes (CMS), each of which causes specific molecular defects. In addition, we mention the neurotoxins from bacteria, snakes and many other species that interfere with neuromuscular transmission and cause potentially fatal diseases, but have also provided useful probes for investigating neuromuscular transmission. There are also changes in NMJ structure and function in motor neuron disease, spinal muscle atrophy and sarcopenia that are likely to be secondary but might provide treatment targets. The NMJ is one of the best studied and most disease-prone synapses in the nervous system and it is amenable to in vivo and ex vivo investigation and to systemic therapies that can help restore normal function.
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Affiliation(s)
- Pedro M. Rodríguez Cruz
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Judith Cossins
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - David Beeson
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- Neurosciences Group, Weatherall Institute of Molecular Medicine, University of Oxford, The John Radcliffe Hospital, Oxford, United Kingdom
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5
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Péladeau C, Jasmin BJ. Targeting IRES-dependent translation as a novel approach for treating Duchenne muscular dystrophy. RNA Biol 2020; 18:1238-1251. [PMID: 33164678 DOI: 10.1080/15476286.2020.1847894] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Internal-ribosomal entry sites (IRES) are translational elements that allow the initiation machinery to start protein synthesis via internal initiation. IRESs promote tissue-specific translation in stress conditions when conventional cap-dependent translation is inhibited. Since many IRES-containing mRNAs are relevant to diseases, this cellular mechanism is emerging as an attractive therapeutic target for pharmacological and genetic modulations. Indeed, there has been growing interest over the past years in determining the therapeutic potential of IRESs for several disease conditions such as cancer, neurodegeneration and neuromuscular diseases including Duchenne muscular dystrophy (DMD). IRESs relevant for DMD have been identified in several transcripts whose protein product results in functional improvements in dystrophic muscles. Together, these converging lines of evidence indicate that activation of IRES-mediated translation of relevant transcripts in DMD muscle represents a novel and appropriate therapeutic strategy for DMD that warrants further investigation, particularly to identify agents that can modulate their activity.
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Affiliation(s)
- Christine Péladeau
- Department of Cellular and Molecular Medicine, and the Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, and the Eric Poulin Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
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6
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Belotti E, Schaeffer L. Regulation of Gene expression at the neuromuscular Junction. Neurosci Lett 2020; 735:135163. [PMID: 32553805 DOI: 10.1016/j.neulet.2020.135163] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2020] [Revised: 06/11/2020] [Accepted: 06/14/2020] [Indexed: 01/08/2023]
Abstract
Gene expression in skeletal muscle is profoundly changed upon innervation. 50 years of research on the neuromuscular system have greatly increased our understanding of the mechanisms underlying these changes. By controlling the expression and the activity of key transcription factors, nerve-evoked electrical activity in the muscle fiber positively and negatively regulates the expression of hundreds of genes. Innervation also compartmentalizes gene expression into synaptic and extra-synaptic regions of muscle fibers. In addition, electrically-evoked, release of several factors (e.g. Agrin, Neuregulin, Wnt ligands) induce the clustering of synaptic proteins and of a few muscle nuclei. The sub-synaptic nuclei acquire a particular chromatin organization and develop a specific gene expression program dedicated to building and maintaining a functional neuromuscular synapse. Deciphering synapse-specific, transcriptional regulation started with the identification of the N-box, a six base pair element present in the promoters of the acetylcholine δ and ε subunits. Most genes with synapse-specific expression turned out to contain at least one N-box in their promoters. The N-box is a response element for the synaptic signals Agrin and Neuregulins as well as a binding site for transcription factors of the Ets family. The Ets transcription factors GABP and Erm are implicated in the activation of post-synaptic genes via the N-box. In muscle fibers, Erm expression is restricted to the NMJ whereas GABP is expressed in all muscle nuclei but phosphorylated and activated by the JNK and ERK signaling pathways in response to Agrin and Neuregulins. Post-synaptic gene expression also correlates with chromatin modifications at the genomic level as evidenced by the strong enrichment of decondensed chromatin and acetylated histones in sub-synaptic nuclei. Here we discuss these transcriptional pathways for synaptic specialization at NMJs.
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Affiliation(s)
- Edwige Belotti
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France
| | - Laurent Schaeffer
- INMG, Inserm U1217, CNRS UMR5310, Université Lyon 1, Université De Lyon, Lyon, France; Centre De Biotechnologie Cellulaire, Hospices Civils De Lyon, Lyon, France.
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7
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Péladeau C, Adam N, Bronicki LM, Coriati A, Thabet M, Al-Rewashdy H, Vanstone J, Mears A, Renaud JM, Holcik M, Jasmin BJ. Identification of therapeutics that target eEF1A2 and upregulate utrophin A translation in dystrophic muscles. Nat Commun 2020; 11:1990. [PMID: 32332749 PMCID: PMC7181625 DOI: 10.1038/s41467-020-15971-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/06/2020] [Indexed: 01/10/2023] Open
Abstract
Up-regulation of utrophin in muscles represents a promising therapeutic strategy for the treatment of Duchenne Muscular Dystrophy. We previously demonstrated that eEF1A2 associates with the 5’UTR of utrophin A to promote IRES-dependent translation. Here, we examine whether eEF1A2 directly regulates utrophin A expression and identify via an ELISA-based high-throughput screen, FDA-approved drugs that upregulate both eEF1A2 and utrophin A. Our results show that transient overexpression of eEF1A2 in mouse muscles causes an increase in IRES-mediated translation of utrophin A. Through the assessment of our screen, we reveal 7 classes of FDA-approved drugs that increase eEF1A2 and utrophin A protein levels. Treatment of mdx mice with the 2 top leads results in multiple improvements of the dystrophic phenotype. Here, we report that IRES-mediated translation of utrophin A via eEF1A2 is a critical mechanism of regulating utrophin A expression and reveal the potential of repurposed drugs for treating DMD via this pathway. One potential approach for the treatment of Duchenne muscular dysrophy is to increase expression of the dystrophin homolog utrophin. Here, the authors show that eEF1A2 regulates utrophin expression, and show that 2 FDA-approved drugs upregulate eEIF1A2 and utrophin level in mice, leading to improvement of the dystrophic phenotype.
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Affiliation(s)
- Christine Péladeau
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.,Centre for Neuromuscular Disease, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Nadine Adam
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.,Centre for Neuromuscular Disease, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Lucas M Bronicki
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.,Centre for Neuromuscular Disease, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Adèle Coriati
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Mohamed Thabet
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Hasanen Al-Rewashdy
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.,Centre for Neuromuscular Disease, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Jason Vanstone
- Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 5B2, Canada
| | - Alan Mears
- Apoptosis Research Centre, Children's Hospital of Eastern Ontario Research Institute, 401 Smyth Road, Ottawa, ON, K1H 5B2, Canada
| | - Jean-Marc Renaud
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Martin Holcik
- Department of Health Sciences, Carleton University, 1125 Colonel By Drive, Ottawa, ON, K1S 5B6, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada. .,Centre for Neuromuscular Disease, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada.
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8
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Salmaninejad A, Jafari Abarghan Y, Bozorg Qomi S, Bayat H, Yousefi M, Azhdari S, Talebi S, Mojarrad M. Common therapeutic advances for Duchenne muscular dystrophy (DMD). Int J Neurosci 2020; 131:370-389. [DOI: 10.1080/00207454.2020.1740218] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Arash Salmaninejad
- Halal Research Center of IRI, FDA, Tehran, Iran
- Medical Genetics Research Center, Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Yousef Jafari Abarghan
- Medical Genetics Research Center, Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Saeed Bozorg Qomi
- Medical Genetics Research Center, Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hadi Bayat
- Medical Nano-Technology & Tissue Engineering Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Tissue Engineering and Applied Cell Sciences, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Molecular Genetics, Faculty of Biological Sciences, Tarbiat Modares University, Tehran, Iran
| | - Meysam Yousefi
- Department of Medical Genetics Faculty of Medicine, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran
| | - Sara Azhdari
- Department of Anatomy and Embryology, School of Medicine, Bam University of Medical Sciences, Bam, Iran
| | - Samaneh Talebi
- Medical Genetics Research Center, Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Majid Mojarrad
- Medical Genetics Research Center, Department of Medical Genetics, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
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9
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High-throughput identification of post-transcriptional utrophin up-regulators for Duchenne muscle dystrophy (DMD) therapy. Sci Rep 2020; 10:2132. [PMID: 32034254 PMCID: PMC7005813 DOI: 10.1038/s41598-020-58737-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2019] [Accepted: 12/06/2019] [Indexed: 12/31/2022] Open
Abstract
Upregulation of endogenous utrophin offers great promise for treating DMD, as it can functionally compensate for the lack of dystrophin caused by DMD gene mutations, without the immunogenic concerns associated with delivering dystrophin. However, post-transcriptional repression mechanisms targeting the 5′ and 3′ untranslated regions (UTRs) of utrophin mRNA significantly limit the magnitude of utrophin upregulation achievable by promoter activation. Using a utrophin 5′3′UTR reporter assay, we performed a high-throughput screen (HTS) for small molecules capable of relieving utrophin post-transcriptional repression. We identified 27 hits that were ranked using a using an algorithm that we designed for hit prioritization that we call Hit to Lead Prioritization Score (H2LPS). The top 10 hits were validated using an orthogonal assay for endogenous utrophin expression. Evaluation of the top scoring hit, Trichostatin A (TSA), demonstrated utrophin upregulation and functional improvement in the mdx mouse model of DMD. TSA and the other small molecules identified here represent potential starting points for DMD drug discovery efforts.
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10
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Wilkinson IVL, Perkins KJ, Dugdale H, Moir L, Vuorinen A, Chatzopoulou M, Squire SE, Monecke S, Lomow A, Geese M, Charles PD, Burch P, Tinsley JM, Wynne GM, Davies SG, Wilson FX, Rastinejad F, Mohammed S, Davies KE, Russell AJ. Chemical Proteomics and Phenotypic Profiling Identifies the Aryl Hydrocarbon Receptor as a Molecular Target of the Utrophin Modulator Ezutromid. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201912392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Isabel V. L. Wilkinson
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Kelly J. Perkins
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene Function South Parks Road Oxford OX1 3PT UK
| | - Hannah Dugdale
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene Function South Parks Road Oxford OX1 3PT UK
| | - Lee Moir
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene Function South Parks Road Oxford OX1 3PT UK
| | - Aini Vuorinen
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Maria Chatzopoulou
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Sarah E. Squire
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene Function South Parks Road Oxford OX1 3PT UK
| | - Sebastian Monecke
- Evotec International GmbHManfred Eigen Campus Essener Bogen 7 22419 Hamburg Germany
| | - Alexander Lomow
- Evotec International GmbHManfred Eigen Campus Essener Bogen 7 22419 Hamburg Germany
| | - Marcus Geese
- Evotec International GmbHManfred Eigen Campus Essener Bogen 7 22419 Hamburg Germany
| | - Philip D. Charles
- Department of BiochemistryUniversity of Oxford South Parks Rd Oxford OX1 3QU UK
- Target Discovery InstituteUniversity of OxfordOld Road Campus Roosevelt Drive Oxford OX3 7FZ UK
| | - Peter Burch
- Summit Therapeutics plc. 136a Eastern Avenue, Milton Park Abingdon Oxfordshire OX14 4SB UK
| | - Jonathan M. Tinsley
- Summit Therapeutics plc. 136a Eastern Avenue, Milton Park Abingdon Oxfordshire OX14 4SB UK
| | - Graham M. Wynne
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Stephen G. Davies
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
| | - Francis X. Wilson
- Summit Therapeutics plc. 136a Eastern Avenue, Milton Park Abingdon Oxfordshire OX14 4SB UK
| | - Fraydoon Rastinejad
- Target Discovery InstituteUniversity of OxfordOld Road Campus Roosevelt Drive Oxford OX3 7FZ UK
| | - Shabaz Mohammed
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
- Department of BiochemistryUniversity of Oxford South Parks Rd Oxford OX1 3QU UK
| | - Kay E. Davies
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene Function South Parks Road Oxford OX1 3PT UK
| | - Angela J. Russell
- Department of ChemistryUniversity of OxfordChemistry Research Laboratory Mansfield Road Oxford OX1 3TA UK
- Department of PharmacologyUniversity of Oxford Mansfield Road Oxford OX1 3PQ UK
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11
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Wilkinson IVL, Perkins KJ, Dugdale H, Moir L, Vuorinen A, Chatzopoulou M, Squire SE, Monecke S, Lomow A, Geese M, Charles PD, Burch P, Tinsley JM, Wynne GM, Davies SG, Wilson FX, Rastinejad F, Mohammed S, Davies KE, Russell AJ. Chemical Proteomics and Phenotypic Profiling Identifies the Aryl Hydrocarbon Receptor as a Molecular Target of the Utrophin Modulator Ezutromid. Angew Chem Int Ed Engl 2020; 59:2420-2428. [PMID: 31755636 PMCID: PMC7003794 DOI: 10.1002/anie.201912392] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/13/2019] [Indexed: 12/20/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a fatal muscle-wasting disease arising from mutations in the dystrophin gene. Upregulation of utrophin to compensate for the missing dystrophin offers a potential therapy independent of patient genotype. The first-in-class utrophin modulator ezutromid/SMT C1100 was developed from a phenotypic screen through to a Phase 2 clinical trial. Promising efficacy and evidence of target engagement was observed in DMD patients after 24 weeks of treatment, however trial endpoints were not met after 48 weeks. The objective of this study was to understand the mechanism of action of ezutromid which could explain the lack of sustained efficacy and help development of new generations of utrophin modulators. Using chemical proteomics and phenotypic profiling we show that the aryl hydrocarbon receptor (AhR) is a target of ezutromid. Several lines of evidence demonstrate that ezutromid binds AhR with an apparent KD of 50 nm and behaves as an AhR antagonist. Furthermore, other reported AhR antagonists also upregulate utrophin, showing that this pathway, which is currently being explored in other clinical applications including oncology and rheumatoid arthritis, could also be exploited in future DMD therapies.
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Affiliation(s)
- Isabel V. L. Wilkinson
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Kelly J. Perkins
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene FunctionSouth Parks RoadOxfordOX1 3PTUK
| | - Hannah Dugdale
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene FunctionSouth Parks RoadOxfordOX1 3PTUK
| | - Lee Moir
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene FunctionSouth Parks RoadOxfordOX1 3PTUK
| | - Aini Vuorinen
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Maria Chatzopoulou
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Sarah E. Squire
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene FunctionSouth Parks RoadOxfordOX1 3PTUK
| | - Sebastian Monecke
- Evotec International GmbHManfred Eigen CampusEssener Bogen 722419HamburgGermany
| | - Alexander Lomow
- Evotec International GmbHManfred Eigen CampusEssener Bogen 722419HamburgGermany
| | - Marcus Geese
- Evotec International GmbHManfred Eigen CampusEssener Bogen 722419HamburgGermany
| | - Philip D. Charles
- Department of BiochemistryUniversity of OxfordSouth Parks RdOxfordOX1 3QUUK
- Target Discovery InstituteUniversity of OxfordOld Road CampusRoosevelt DriveOxfordOX3 7FZUK
| | - Peter Burch
- Summit Therapeutics plc.136a Eastern Avenue, Milton ParkAbingdonOxfordshireOX14 4SBUK
| | - Jonathan M. Tinsley
- Summit Therapeutics plc.136a Eastern Avenue, Milton ParkAbingdonOxfordshireOX14 4SBUK
| | - Graham M. Wynne
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Stephen G. Davies
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
| | - Francis X. Wilson
- Summit Therapeutics plc.136a Eastern Avenue, Milton ParkAbingdonOxfordshireOX14 4SBUK
| | - Fraydoon Rastinejad
- Target Discovery InstituteUniversity of OxfordOld Road CampusRoosevelt DriveOxfordOX3 7FZUK
| | - Shabaz Mohammed
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
- Department of BiochemistryUniversity of OxfordSouth Parks RdOxfordOX1 3QUUK
| | - Kay E. Davies
- Department of Physiology, Anatomy and GeneticsUniversity of OxfordSir Henry Wellcome Building of Gene FunctionSouth Parks RoadOxfordOX1 3PTUK
| | - Angela J. Russell
- Department of ChemistryUniversity of OxfordChemistry Research LaboratoryMansfield RoadOxfordOX1 3TAUK
- Department of PharmacologyUniversity of OxfordMansfield RoadOxfordOX1 3PQUK
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12
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Chiappalupi S, Salvadori L, Luca G, Riuzzi F, Calafiore R, Donato R, Sorci G. Do porcine Sertoli cells represent an opportunity for Duchenne muscular dystrophy? Cell Prolif 2019; 52:e12599. [PMID: 30912260 PMCID: PMC6536415 DOI: 10.1111/cpr.12599] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Revised: 01/24/2019] [Accepted: 02/09/2019] [Indexed: 12/13/2022] Open
Abstract
Sertoli cells (SeC) are responsible for the immunoprivileged status of the testis thanks to which allogeneic or xenogeneic engraftments can survive without pharmacological immune suppression if co‐injected with SeC. This peculiar ability of SeC is dependent on secretion of a plethora of factors including maturation factors, hormones, growth factors, cytokines and immunomodulatory factors. The anti‐inflammatory and trophic properties of SeC have been largely exploited in several experimental models of diseases, diabetes being the most studied. Duchenne muscular dystrophy (DMD) is a lethal X‐linked recessive pathology in which lack of functional dystrophin leads to progressive muscle degeneration culminating in loss of locomotion and premature death. Despite a huge effort to find a cure, DMD patients are currently treated with anti‐inflammatory steroids. Recently, encapsulated porcine SeC (MC‐SeC) have been injected ip in the absence of immunosuppression in an animal model of DMD resulting in reduction of muscle inflammation and amelioration of muscle morphology and functionality, thus opening an additional avenue in the treatment of DMD. The novel protocol is endowed with the advantage of being potentially applicable to all the cohort of DMD patients regardless of the mutation. This mini‐review addresses several issues linked to the possible use of MC‐SeC injected ip in dystrophic people.
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Affiliation(s)
- Sara Chiappalupi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Interuniversity Institute of Myology (IIM), Perugia, Italy
| | - Laura Salvadori
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Interuniversity Institute of Myology (IIM), Perugia, Italy
| | - Giovanni Luca
- Department of Experimental Medicine, University of Perugia, Perugia, Italy
| | - Francesca Riuzzi
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Interuniversity Institute of Myology (IIM), Perugia, Italy
| | | | - Rosario Donato
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Interuniversity Institute of Myology (IIM), Perugia, Italy.,Centro Universitario di Ricerca sulla Genomica Funzionale, University of Perugia, Perugia, Italy
| | - Guglielmo Sorci
- Department of Experimental Medicine, University of Perugia, Perugia, Italy.,Interuniversity Institute of Myology (IIM), Perugia, Italy.,Centro Universitario di Ricerca sulla Genomica Funzionale, University of Perugia, Perugia, Italy
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13
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Guiraud S, Roblin D, Kay DE. The potential of utrophin modulators for the treatment of Duchenne muscular dystrophy. Expert Opin Orphan Drugs 2018. [DOI: 10.1080/21678707.2018.1438261] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Simon Guiraud
- Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | | | - Davies. E. Kay
- Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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14
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Juretić N, Díaz J, Romero F, González G, Jaimovich E, Riveros N. Interleukin-6 and neuregulin-1 as regulators of utrophin expression via the activation of NRG-1/ErbB signaling pathway in mdx cells. Biochim Biophys Acta Mol Basis Dis 2017; 1863:770-780. [DOI: 10.1016/j.bbadis.2016.12.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 11/10/2016] [Accepted: 12/12/2016] [Indexed: 01/16/2023]
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15
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Chiappalupi S, Luca G, Mancuso F, Madaro L, Fallarino F, Nicoletti C, Calvitti M, Arato I, Falabella G, Salvadori L, Di Meo A, Bufalari A, Giovagnoli S, Calafiore R, Donato R, Sorci G. Intraperitoneal injection of microencapsulated Sertoli cells restores muscle morphology and performance in dystrophic mice. Biomaterials 2015; 75:313-326. [PMID: 26523508 DOI: 10.1016/j.biomaterials.2015.10.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2015] [Revised: 09/30/2015] [Accepted: 10/14/2015] [Indexed: 11/27/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a genetic disease characterized by progressive muscle degeneration leading to impaired locomotion, respiratory failure and premature death. In DMD patients, inflammatory events secondary to dystrophin mutation play a major role in the progression of the pathology. Sertoli cells (SeC) have been largely used to protect xenogeneic engraftments or induce trophic effects thanks to their ability to secrete trophic, antiinflammatory, and immunomodulatory factors. Here we have purified SeC from specific pathogen-free (SPF)-certified neonatal pigs, and embedded them into clinical grade alginate microcapsules. We show that a single intraperitoneal injection of microencapsulated SPF SeC (SeC-MC) in an experimental model of DMD can rescue muscle morphology and performance in the absence of pharmacologic immunosuppressive treatments. Once i.p. injected, SeC-MC act as a drug delivery system that modulates the inflammatory response in muscle tissue, and upregulates the expression of the dystrophin paralogue, utrophin in muscles through systemic release of heregulin-β1, thus promoting sarcolemma stability. Analyses performed five months after single injection show high biocompatibility and long-term efficacy of SeC-MC. Our results might open new avenues for the treatment of patients with DMD and related diseases.
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Affiliation(s)
- Sara Chiappalupi
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy; Interuniversity Institute of Myology (IIM), Italy
| | - Giovanni Luca
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Francesca Mancuso
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Luca Madaro
- IRCCS Fondazione Santa Lucia, Rome 00143, Italy; National Research Council, Institute of Cell Biology and Neurobiology, Fondazione Santa Lucia, Rome 00143, Italy; Interuniversity Institute of Myology (IIM), Italy
| | - Francesca Fallarino
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Carmine Nicoletti
- Unit of Histology, DAHFMO, La Sapienza University, Rome 00161, Italy; Interuniversity Institute of Myology (IIM), Italy
| | - Mario Calvitti
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Iva Arato
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Giulia Falabella
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Laura Salvadori
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy
| | - Antonio Di Meo
- Department of Veterinary Medicine, University of Perugia, Perugia 06126, Italy
| | - Antonello Bufalari
- Department of Veterinary Medicine, University of Perugia, Perugia 06126, Italy
| | - Stefano Giovagnoli
- Department of Pharmaceutical Sciences, University of Perugia, Perugia 06123, Italy
| | | | - Rosario Donato
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy; Interuniversity Institute of Myology (IIM), Italy
| | - Guglielmo Sorci
- Department of Experimental Medicine, University of Perugia, Perugia 06132, Italy; Interuniversity Institute of Myology (IIM), Italy.
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16
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Gintjee TJJ, Magh ASH, Bertoni C. High throughput screening in duchenne muscular dystrophy: from drug discovery to functional genomics. BIOLOGY 2014; 3:752-80. [PMID: 25405319 PMCID: PMC4280510 DOI: 10.3390/biology3040752] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 10/28/2014] [Accepted: 10/30/2014] [Indexed: 01/16/2023]
Abstract
Centers for the screening of biologically active compounds and genomic libraries are becoming common in the academic setting and have enabled researchers devoted to developing strategies for the treatment of diseases or interested in studying a biological phenomenon to have unprecedented access to libraries that, until few years ago, were accessible only by pharmaceutical companies. As a result, new drugs and genetic targets have now been identified for the treatment of Duchenne muscular dystrophy (DMD), the most prominent of the neuromuscular disorders affecting children. Although the work is still at an early stage, the results obtained to date are encouraging and demonstrate the importance that these centers may have in advancing therapeutic strategies for DMD as well as other diseases. This review will provide a summary of the status and progress made toward the development of a cure for this disorder and implementing high-throughput screening (HTS) technologies as the main source of discovery. As more academic institutions are gaining access to HTS as a valuable discovery tool, the identification of new biologically active molecules is likely to grow larger. In addition, the presence in the academic setting of experts in different aspects of the disease will offer the opportunity to develop novel assays capable of identifying new targets to be pursued as potential therapeutic options. These assays will represent an excellent source to be used by pharmaceutical companies for the screening of larger libraries providing the opportunity to establish strong collaborations between the private and academic sectors and maximizing the chances of bringing into the clinic new drugs for the treatment of DMD.
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Affiliation(s)
- Thomas J J Gintjee
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, 710 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - Alvin S H Magh
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, 710 Westwood Plaza, Los Angeles, CA 90095, USA.
| | - Carmen Bertoni
- Department of Neurology, David Geffen School of Medicine, University of California Los Angeles, 710 Westwood Plaza, Los Angeles, CA 90095, USA.
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D'Arcy CE, Feeney SJ, McLean CA, Gehrig SM, Lynch GS, Smith JE, Cowling BS, Mitchell CA, McGrath MJ. Identification of FHL1 as a therapeutic target for Duchenne muscular dystrophy. Hum Mol Genet 2013; 23:618-36. [PMID: 24087791 DOI: 10.1093/hmg/ddt449] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Utrophin is a potential therapeutic target for the fatal muscle disease, Duchenne muscular dystrophy (DMD). In adult skeletal muscle, utrophin is restricted to the neuromuscular and myotendinous junctions and can compensate for dystrophin loss in mdx mice, a mouse model of DMD, but requires sarcolemmal localization. NFATc1-mediated transcription regulates utrophin expression and the LIM protein, FHL1 which promotes muscle hypertrophy, is a transcriptional activator of NFATc1. By generating mdx/FHL1-transgenic mice, we demonstrate that FHL1 potentiates NFATc1 activation of utrophin to ameliorate the dystrophic pathology. Transgenic FHL1 expression increased sarcolemmal membrane stability, reduced muscle degeneration, decreased inflammation and conferred protection from contraction-induced injury in mdx mice. Significantly, FHL1 expression also reduced progressive muscle degeneration and fibrosis in the diaphragm of aged mdx mice. FHL1 enhanced NFATc1 activation of the utrophin promoter and increased sarcolemmal expression of utrophin in muscles of mdx mice, directing the assembly of a substitute utrophin-glycoprotein complex, and revealing a novel FHL1-NFATc1-utrophin signaling axis that can functionally compensate for dystrophin.
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Affiliation(s)
- Colleen E D'Arcy
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, VIC 3800, Australia
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18
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AMP-activated protein kinase at the nexus of therapeutic skeletal muscle plasticity in Duchenne muscular dystrophy. Trends Mol Med 2013; 19:614-24. [PMID: 23891277 DOI: 10.1016/j.molmed.2013.07.002] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Revised: 06/26/2013] [Accepted: 07/01/2013] [Indexed: 12/22/2022]
Abstract
Recent studies have highlighted the potential of adenosine monophosphate-activated protein kinase (AMPK) to act as a central therapeutic target in Duchenne muscular dystrophy (DMD). Here, we review the role of AMPK as an important integrator of cell signaling pathways that mediate phenotypic plasticity within the context of dystrophic skeletal muscle. Pharmacological AMPK activation remodels skeletal muscle towards a slower, more oxidative phenotype, which is more pathologically resistant to the lack of dystrophin. Moreover, recent studies suggest that AMPK-activated autophagy may be beneficial for myofiber structure and function in mice with muscular dystrophy. Thus, AMPK may represent an ideal target for intervention because clinically approved pharmacological agonists exist, and because benefits can be derived via two independent yet, complementary biological pathways. The availability of several AMPK activators could therefore lead to the rapid development and implementation of novel and highly effective therapeutics aimed at altering the relentless progression of DMD.
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Amirouche A, Tadesse H, Lunde JA, Bélanger G, Côté J, Jasmin BJ. Activation of p38 signaling increases utrophin A expression in skeletal muscle via the RNA-binding protein KSRP and inhibition of AU-rich element-mediated mRNA decay: implications for novel DMD therapeutics. Hum Mol Genet 2013; 22:3093-111. [PMID: 23575223 DOI: 10.1093/hmg/ddt165] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Several therapeutic approaches are currently being developed for Duchenne muscular dystrophy (DMD) including upregulating the levels of endogenous utrophin A in dystrophic fibers. Here, we examined the role of post-transcriptional mechanisms in controlling utrophin A expression in skeletal muscle. We show that activation of p38 leads to an increase in utrophin A independently of a transcriptional induction. Rather, p38 controls the levels of utrophin A mRNA by extending the half-life of transcripts via AU-rich elements (AREs). This mechanism critically depends on a decrease in the functional availability of KSRP, an RNA-binding protein known to promote decay of ARE-containing transcripts. In vitro and in vivo binding studies revealed that KSRP interacts with specific AREs located within the utrophin A 3' UTR. Electroporation experiments to knockdown KSRP led to an increase in utrophin A in wild-type and mdx mouse muscles. In pre-clinical studies, treatment of mdx mice with heparin, an activator of p38, causes a pronounced increase in utrophin A in diaphragm muscle fibers. Together, these studies identify a pathway that culminates in the post-transcriptional regulation of utrophin A through increases in mRNA stability. Furthermore, our results constitute proof-of-principle showing that pharmacological activation of p38 may prove beneficial as a novel therapeutic approach for DMD.
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Affiliation(s)
- Adel Amirouche
- Faculty of Medicine, Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, University of Ottawa, ON, Canada K1H 8M5
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20
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Moorwood C, Khurana TS. Duchenne muscular dystrophy drug discovery - the application of utrophin promoter activation screening. Expert Opin Drug Discov 2013; 8:569-81. [PMID: 23473647 DOI: 10.1517/17460441.2013.777040] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
INTRODUCTION Duchenne muscular dystrophy (DMD) is a devastating genetic muscle wasting disease caused by mutations in the DMD gene that in turn lead to an absence of dystrophin. Currently, there is no definitive therapy for DMD. Gene- and cell-based therapies designed to replace dystrophin have met some degree of success, as have strategies that seek to improve the dystrophic pathology independent of dystrophin. AREAS COVERED In this review the authors focus on utrophin promoter activation-based strategies and their implications on potential therapeutics for DMD. These strategies in common are designed to identify drugs/small molecules that can activate the utrophin promoter and would allow the functional substitution of dystrophin by upregulating utrophin expression in dystrophic muscle. The authors provide an overview of utrophin biology with a focus on regulation of the utrophin promoter and discuss current attempts in identifying utrophin promoter-activating molecules using high-throughput screening (HTS). EXPERT OPINION The characterisation of utrophin promoter regulatory mechanisms coupled with advances in HTS have allowed researchers to undertake screens and identify a number of promising lead compounds that may prove useful for DMD. In principle, these pharmacological compounds offer significant advantages from a translational viewpoint for developing DMD therapeutics.
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Affiliation(s)
- Catherine Moorwood
- University of Pennsylvania School of Dental Medicine, Department of Anatomy & Cell Biology, 438 Levy Research Building, 240 S. 40th Street, Philadelphia, PA 19104, USA
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21
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Moorwood C, Soni N, Patel G, Wilton SD, Khurana TS. A cell-based high-throughput screening assay for posttranscriptional utrophin upregulation. ACTA ACUST UNITED AC 2012; 18:400-6. [PMID: 23112083 DOI: 10.1177/1087057112465648] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating muscle-wasting disease caused by mutations in the dystrophin gene. Utrophin is a homologue of dystrophin that can compensate for its absence when overexpressed in DMD animal models. Utrophin upregulation is therefore a promising therapeutic approach for DMD. Utrophin is regulated at both transcriptional and posttranscriptional levels. Transcriptional regulation has been studied extensively, and assays have been described for the identification of utrophin promoter-targeting molecules. However, despite the profound impact that posttranscriptional regulation has on utrophin expression, screening assays have not yet been described that could be used to discover pharmaceuticals targeting this key phase of regulation. We describe the development and validation of a muscle cell line-based assay in which a stably expressed luciferase coding sequence is flanked by the utrophin 5'- and 3'-untranslated regions (UTRs). The assay was validated using the posttranscriptional regulation of utrophin by miR-206. The assay has a Z' of 0.7, indicating robust performance in high-throughput format. This assay can be used to study utrophin regulatory mechanisms or to screen chemical libraries for compounds that upregulate utrophin posttranscriptionally via its UTRs. Compounds identified via this assay, used alone or in a synergistic combination with utrophin promoter-targeting molecules, would be predicted to have therapeutic potential for DMD.
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Affiliation(s)
- Catherine Moorwood
- University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
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Perronnet C, Chagneau C, Le Blanc P, Samson-Desvignes N, Mornet D, Laroche S, De La Porte S, Vaillend C. Upregulation of brain utrophin does not rescue behavioral alterations in dystrophin-deficient mice. Hum Mol Genet 2012; 21:2263-76. [PMID: 22343141 DOI: 10.1093/hmg/dds047] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Dystrophin, the protein responsible for X-linked Duchenne muscular dystrophy (DMD), is normally expressed in both muscle and brain, which explains that its loss also leads to cognitive deficits. The utrophin protein, an autosomal homolog, is a natural candidate for dystrophin replacement in patients. Pharmacological upregulation of endogenous utrophin improves muscle physiology in dystrophin-deficient mdx mice, and represents a potential therapeutic tool that has the advantage of allowing delivery to various organs following peripheral injections. Whether this could alleviate cognitive deficits, however, has not been explored. Here, we first investigated basal expression of all utrophins and dystrophins in the brain of mdx mice and found no evidence for spontaneous compensation by utrophins. Then, we show that systemic chronic, spaced injections of arginine butyrate (AB) alleviate muscle alterations and upregulate utrophin expression in the adult brain of mdx mice. AB selectively upregulated brain utrophin Up395, while reducing expression of Up113 and Up71. This, however, was not associated with a significant improvement of behavioral functions typically affected in mdx mice, which include exploration, emotional reactivity, spatial and fear memories. We suggest that AB did not overcome behavioral and cognitive dysfunctions because the regional and cellular expression of utrophins did not coincide with dystrophin expression in untreated mice, nor did it in AB-treated mice. While treatments based on the modulation of utrophin may alleviate DMD phenotypes in certain organs and tissues that coexpress dystrophins and utrophins in the same cells, improvement of cognitive functions would likely require acting on specific dystrophin-dependent mechanisms.
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Affiliation(s)
- Caroline Perronnet
- Univ Paris-Sud, Centre de Neurosciences Paris-Sud, UMR8195, Orsay F-91405, France
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23
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Basu U, Lozynska O, Moorwood C, Patel G, Wilton SD, Khurana TS. Translational regulation of utrophin by miRNAs. PLoS One 2011; 6:e29376. [PMID: 22216264 PMCID: PMC3246502 DOI: 10.1371/journal.pone.0029376] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 11/28/2011] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Utrophin is the autosomal homolog of dystrophin, the product of the Duchenne Muscular Dystrophy (DMD) locus. Its regulation is of therapeutic interest as its overexpression can compensate for dystrophin's absence in animal models of DMD. The tissue distribution and transcriptional regulation of utrophin have been characterized extensively, and more recently translational control mechanisms that may underlie its complex expression patterns have begun to be identified. METHODOLOGY/PRINCIPAL FINDINGS Using a variety of bioinformatic, molecular and cell biology techniques, we show that the muscle isoform utrophin-A is predominantly suppressed at the translational level in C2C12 myoblasts. The extent of translational inhibition is estimated to be ~99% in C2C12 cells and is mediated by both the 5'- and 3'-UTRs of the utrophin-A mRNA. In this study we identify five miRNAs (let-7c, miR-150, miR-196b, miR-296-5p, miR-133b) that mediate the repression, and confirm repression by the previously identified miR-206. We demonstrate that this translational repression can be overcome by blocking the actions of miRNAs, resulting in an increased level of utrophin protein in C2C12 cells. CONCLUSIONS/SIGNIFICANCE The present study has identified key inhibitory mechanisms featuring miRNAs that regulate utrophin expression, and demonstrated that these mechanisms can be targeted to increase endogenous utrophin expression in cultured muscle cells. We suggest that miRNA-mediated inhibitory mechanisms could be targeted by methods similar to those described here as a novel strategy to increase utrophin expression as a therapy for DMD.
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Affiliation(s)
- Utpal Basu
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Olga Lozynska
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Catherine Moorwood
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Gopal Patel
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Steve D. Wilton
- Centre for Neuromuscular and Neurological Disorders, University of Western Australia, Perth, Australia
| | - Tejvir S. Khurana
- Department of Physiology, Pennsylvania Muscle Institute, School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
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Abstract
Duchenne muscular dystrophy is a devastating muscular dystrophy of childhood. Mutations in the dystrophin gene destroy the link between the internal muscle filaments and the extracellular matrix, resulting in severe muscle weakness and progressive muscle wasting. There is currently no cure and, whilst palliative treatment has improved, affected boys are normally confined to a wheelchair by 12 years of age and die from respiratory or cardiac complications in their twenties or thirties. Therapies currently being developed include mutation-specific treatments, DNA- and cell-based therapies, and drugs which aim to modulate cellular pathways or gene expression. This review aims to provide an overview of the different therapeutic approaches aimed at reconstructing the dystrophin-associated protein complex, including restoration of dystrophin expression and upregulation of the functional homologue, utrophin.
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Affiliation(s)
- Rebecca J Fairclough
- MRC Functional Genomics Unit, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford UK
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26
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The cleavage of HuR interferes with its transportin-2-mediated nuclear import and promotes muscle fiber formation. Cell Death Differ 2010; 17:1588-99. [PMID: 20379198 DOI: 10.1038/cdd.2010.34] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Although the function of posttranscriptional processes in regulating the expression of genes involved in muscle fiber formation (myogenesis) is well accepted, the mechanisms by which these effects are mediated remain elusive. Here, we uncover such a mechanism and show that during myogenesis, a fraction of the posttranscriptional regulator human antigen R (HuR) is cleaved in a caspase-dependent manner in both cell culture and animal models. Disruption of caspase activity in cultured myoblasts or knocking out the caspase-3 gene in mice significantly reduced HuR cleavage and the cytoplasmic accumulation of HuR in muscle fibers. The non-cleavable isoform of HuR, HuRD226A, failed to reestablish the myogenic potential of HuR-depleted myoblasts. HuR cleavage generates two fragments: HuR-cleavage product 1 (HuR-CP1) (24 kDa) and HuR-CP2 (8 kDa). Here, we show that one of these fragments (HuR-CP1) binds to the HuR import factor transportin-2 (TRN2) allowing HuR to accumulate in the cytoplasm. As this cytoplasmic accumulation is required for the promyogenic function of HuR, our data support a model, whereby during the transition phase from myoblasts to myotubes, a proportion of HuR is cleaved to generate HuR-CP1. By interfering with the TRN2-mediated import of HuR, this CP helps non-cleaved HuR accumulate in the cytoplasm thus promoting myogenesis.
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Lu Y, Tian C, Danialou G, Gilbert R, Petrof BJ, Karpati G, Nalbantoglu J. Targeting artificial transcription factors to the utrophin A promoter: effects on dystrophic pathology and muscle function. J Biol Chem 2008; 283:34720-7. [PMID: 18945675 PMCID: PMC3259868 DOI: 10.1074/jbc.m804518200] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 10/15/2008] [Indexed: 12/21/2022] Open
Abstract
Duchenne muscular dystrophy is caused by a genetic defect in the dystrophin gene. The absence of dystrophin results in muscle fiber necrosis and regeneration, leading to progressive muscle fiber loss. Utrophin is a close analogue of dystrophin. A substantial, ectopic expression of utrophin in the extrasynaptic sarcolemma of dystrophin-deficient muscle fibers can prevent deleterious effects of dystrophin deficiency. An alternative approach for the extrasynaptic up-regulation of utrophin involves the augmentation of utrophin transcription via the endogenous utrophin A promoter using custom-designed transcriptional activator proteins with zinc finger (ZFP) motifs. We tested a panel of custom-designed ZFP for their ability to activate the utrophin A promoter. Expression of one such ZFP efficiently increased, in a time-dependent manner, utrophin transcript and protein levels both in vitro and in vivo. In dystrophic mouse (mdx) muscles, administration of adenoviral vectors expressing this ZFP led to significant enhancement of muscle function with decreased necrosis, restoration of the dystrophin-associated proteins, and improved resistance to eccentric contractions. These studies provide evidence that specifically designed ZFPs can act as strong transcriptional activators of the utrophin A promoter. These may thus serve as attractive therapeutic agents for dystrophin deficiency states such as Duchenne muscular dystrophy.
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Affiliation(s)
- Yifan Lu
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - Chai Tian
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - Gawiyou Danialou
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - Rénald Gilbert
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - Basil J. Petrof
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - George Karpati
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
| | - Josephine Nalbantoglu
- Montreal Neurological Institute and
Department of Neurology & Neurosurgery, McGill University, Montreal,
Quebec H3A 2B4, the Respiratory Division, McGill
University Health Center and Meakins-Christie Laboratories, McGill University,
Montreal, Quebec H3A 1A1, and the Biotechnology
Research Institute, National Research Council Canada, Montreal, Quebec H4P
2R2, Canada
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28
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Chakkalakal JV, Miura P, Bélanger G, Michel RN, Jasmin BJ. Modulation of utrophin A mRNA stability in fast versus slow muscles via an AU-rich element and calcineurin signaling. Nucleic Acids Res 2008; 36:826-38. [PMID: 18084024 PMCID: PMC2241908 DOI: 10.1093/nar/gkm1107] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 11/19/2007] [Accepted: 11/26/2007] [Indexed: 12/12/2022] Open
Abstract
We examined the role of post-transcriptional mechanisms in controlling utrophin A mRNA expression in slow versus fast skeletal muscles. First, we determined that the half-life of utrophin A mRNA is significantly shorter in the presence of proteins isolated from fast muscles. Direct plasmid injection experiments using reporter constructs containing the full-length or truncated variants of the utrophin 3'UTR into slow soleus and fast extensor digitorum longus muscles revealed that a region of 265 nucleotides is sufficient to confer lower levels of reporter mRNA in fast muscles. Further analysis of this region uncovered a conserved AU-rich element (ARE) that suppresses expression of reporter mRNAs in cultured muscle cells. Moreover, stability of reporter mRNAs fused to the utrophin full-length 3'UTR was lower in the presence of fast muscle protein extracts. This destabilization effect seen in vivo was lost upon deletion of the conserved ARE. Finally, we observed that calcineurin signaling affects utrophin A mRNA stability through the conserved ARE. These results indicate that ARE-mediated mRNA decay is a key mechanism that regulates expression of utrophin A mRNA in slow muscle fibers. This is the first demonstration of ARE-mediated mRNA decay regulating the expression of a gene associated with the slow myogenic program.
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Affiliation(s)
- Joe V. Chakkalakal
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Pedro Miura
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Guy Bélanger
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Robin N. Michel
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
| | - Bernard J. Jasmin
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada K1H 8M5, Department of Chemistry and Biochemistry, Department of Exercise Science and Centre for Structural and Functional Genomics, Concordia University, The Richard J. Renaud Science Complex, Montreal, QC, Canada H4B 1R6 and Ottawa Health Research Institute, Molecular Medicine Program, Ottawa Hospital, General Campus, Ottawa, ON, Canada K1H 8L6
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29
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Bandi E, Jevšek M, Mars T, Jurdana M, Formaggio E, Sciancalepore M, Fumagalli G, Grubič Z, Ruzzier F, Lorenzon P. Neural agrin controls maturation of the excitation-contraction coupling mechanism in human myotubes developing in vitro. Am J Physiol Cell Physiol 2008; 294:C66-73. [DOI: 10.1152/ajpcell.00248.2007] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to elucidate the mechanisms responsible for the effects of innervation on the maturation of excitation-contraction coupling apparatus in human skeletal muscle. For this purpose, we compared the establishment of the excitation-contraction coupling mechanism in myotubes differentiated in four different experimental paradigms: 1) aneurally cultured, 2) cocultured with fetal rat spinal cord explants, 3) aneurally cultured in medium conditioned by cocultures, and 4) aneurally cultured in medium supplemented with purified recombinant chick neural agrin. Ca2+ imaging indicated that coculturing human muscle cells with rat spinal cord explants increased the fraction of cells showing a functional excitation-contraction coupling mechanism. The effect of spinal cord explants was mimicked by treatment with medium conditioned by cocultures or by addition of 1 nM of recombinant neural agrin to the medium. The treatment with neural agrin increased the number of human muscle cells in which functional ryanodine receptors (RyRs) and dihydropyridine-sensitive L-type Ca2+ channels were detectable. Our data are consistent with the hypothesis that agrin, released from neurons, controls the maturation of the excitation-contraction coupling mechanism and that this effect is due to modulation of both RyRs and L-type Ca2+ channels. Thus, a novel role for neural agrin in skeletal muscle maturation is proposed.
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30
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Basu U, Gyrd-Hansen M, Baby SM, Lozynska O, Krag TOB, Jensen CJ, Frödin M, Khurana TS. Heregulin-induced epigenetic regulation of the utrophin-A promoter. FEBS Lett 2007; 581:4153-8. [PMID: 17692845 PMCID: PMC2699486 DOI: 10.1016/j.febslet.2007.07.021] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2007] [Revised: 06/22/2007] [Accepted: 07/10/2007] [Indexed: 12/12/2022]
Abstract
Utrophin is the autosomal homolog of dystrophin, the product of the Duchenne's muscular dystrophy (DMD) locus. Utrophin is of therapeutic interest since its over-expression can compensate dystrophin's absence. Utrophin is enriched at neuromuscular junctions due to heregulin-mediated utrophin-A promoter activation. We demonstrate that heregulin activated MSK1/2 and phosphorylated histone H3 at serine 10 in cultured C2C12 muscle cells, in an ERK-dependent manner. MSK1/2 inhibition suppressed heregulin-mediated utrophin-A activation. MSK1 over-expression potentiated heregulin-mediated utrophin-A activation and chromatin remodeling at the utrophin-A promoter. These results identify MSK1/2 as key effectors modulating utrophin-A expression as well as identify novel targets for DMD therapy.
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Affiliation(s)
- Utpal Basu
- Department of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Mads Gyrd-Hansen
- Department of Clinical Biochemistry, Glostrup Hospital, University of Copenhagen, Denmark
| | - Santhosh M. Baby
- Department of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Olga Lozynska
- Department of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Thomas O. B. Krag
- Department of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Copenhagen Muscle Research Centre, University of Copenhagen, Denmark
| | - Claus J. Jensen
- Biotech Research and Innovation Centre and Center for Epigenetics, University of Copenhagen, Denmark
| | - Morten Frödin
- Biotech Research and Innovation Centre and Center for Epigenetics, University of Copenhagen, Denmark
| | - Tejvir S. Khurana
- Department of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, Philadelphia, PA 19104, USA
- Address for correspondence: Tejvir S. Khurana, M.D., Ph.D. Dept. of Physiology & Pennsylvania Muscle Institute, University of Pennsylvania, 3700 Hamilton Walk, Philadelphia, PA 19104-6085 Tel: +1 215 573 2640 Fax: +1 215 573 5851
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31
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Kim YK, Furic L, Parisien M, Major F, DesGroseillers L, Maquat LE. Staufen1 regulates diverse classes of mammalian transcripts. EMBO J 2007; 26:2670-81. [PMID: 17510634 PMCID: PMC1888674 DOI: 10.1038/sj.emboj.7601712] [Citation(s) in RCA: 162] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2007] [Accepted: 04/05/2007] [Indexed: 11/10/2022] Open
Abstract
It is currently unknown how extensively the double-stranded RNA-binding protein Staufen (Stau)1 is utilized by mammalian cells to regulate gene expression. To date, Stau1 binding to the 3'-untranslated region (3'-UTR) of ADP ribosylation factor (ARF)1 mRNA has been shown to target ARF1 mRNA for Stau1-mediated mRNA decay (SMD). ARF1 SMD depends on translation and recruitment of the nonsense-mediated mRNA decay factor Upf1 to the ARF1 3'-UTR by Stau1. Here, we demonstrate that Stau1 binds to a complex structure within the ARF1 3'-UTR. We also use microarrays to show that 1.1 and 1.0% of the 11 569 HeLa-cell transcripts that were analyzed are upregulated and downregulated, respectively, at least two-fold upon Stau1 depletion in three independently performed experiments. We localize the Stau1 binding site to the 3'-UTR of four mRNAs that we define as natural SMD targets. Additionally, we provide evidence that the efficiency of SMD increases during the differentiation of C2C12 myoblasts to myotubes. We propose that Stau1 influences the expression of a wide variety of physiologic transcripts and metabolic pathways.
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Affiliation(s)
- Yoon Ki Kim
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Luc Furic
- Département de Biochimie, Université de Montréal, succursale Centre Ville, Montréal, Québec, Canada
| | - Marc Parisien
- Institut de Recherche en Immunologie et Cancérologie, Université de Montréal, succursale Centre Ville, Montréal, Québec, Canada
| | - François Major
- Institut de Recherche en Immunologie et Cancérologie, Université de Montréal, succursale Centre Ville, Montréal, Québec, Canada
| | - Luc DesGroseillers
- Département de Biochimie, Université de Montréal, succursale Centre Ville, Montréal, Québec, Canada
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 712, Rochester, NY 14642, USA. Tel.: +1 585 273 5640; Fax: +1 585 271 2683; E-mail:
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32
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Perkins KJ, Basu U, Budak MT, Ketterer C, Baby SM, Lozynska O, Lunde JA, Jasmin BJ, Rubinstein NA, Khurana TS. Ets-2 repressor factor silences extrasynaptic utrophin by N-box mediated repression in skeletal muscle. Mol Biol Cell 2007; 18:2864-72. [PMID: 17507653 PMCID: PMC1949368 DOI: 10.1091/mbc.e06-12-1069] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Utrophin is the autosomal homologue of dystrophin, the protein product of the Duchenne's muscular dystrophy (DMD) locus. Utrophin expression is temporally and spatially regulated being developmentally down-regulated perinatally and enriched at neuromuscular junctions (NMJs) in adult muscle. Synaptic localization of utrophin occurs in part by heregulin-mediated extracellular signal-regulated kinase (ERK)-phosphorylation, leading to binding of GABPalpha/beta to the N-box/EBS and activation of the major utrophin promoter-A expressed in myofibers. However, molecular mechanisms contributing to concurrent extrasynaptic silencing that must occur to achieve NMJ localization are unknown. We demonstrate that the Ets-2 repressor factor (ERF) represses extrasynaptic utrophin-A in muscle. Gel shift and chromatin immunoprecipitation studies demonstrated physical association of ERF with the utrophin-A promoter N-box/EBS site. ERF overexpression repressed utrophin-A promoter activity; conversely, small interfering RNA-mediated ERF knockdown enhanced promoter activity as well as endogenous utrophin mRNA levels in cultured muscle cells in vitro. Laser-capture microscopy of tibialis anterior NMJ and extrasynaptic transcriptomes and gene transfer studies provide spatial and direct evidence, respectively, for ERF-mediated utrophin repression in vivo. Together, these studies suggest "repressing repressors" as a potential strategy for achieving utrophin up-regulation in DMD, and they provide a model for utrophin-A regulation in muscle.
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Affiliation(s)
- Kelly J Perkins
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104-6085, USA
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33
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34
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Lok KC, Fu AKY, Ip FCF, Wong YH, Ip NY. Expression of G protein β subunits in rat skeletal muscle after nerve injury: Implication in the regulation of neuregulin signaling. Neuroscience 2007; 146:594-603. [PMID: 17368953 DOI: 10.1016/j.neuroscience.2007.02.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2006] [Revised: 02/02/2007] [Accepted: 02/03/2007] [Indexed: 11/21/2022]
Abstract
Tight regulation of gene transcription is critical in muscle development as well as during the formation and maintenance of the neuromuscular junction (NMJ). We previously demonstrated that the transcription of G protein beta1 (Gbeta1) is enhanced by treatment of cultured myotubes with neuregulin (NRG), a trophic factor that plays an important role in neural development. In the current study, we report that the transcript levels of Gbeta1 and Gbeta2 subunits in skeletal muscle are up-regulated following sciatic nerve injury or blockade of nerve activity. These observations prompted us to explore the possibility that G protein subunits regulate NRG-mediated signaling and gene transcription. We showed that overexpression of Gbeta1 or Gbeta2 in COS7 cells attenuates NRG-induced extracellular signal-regulated kinase (ERK) 1/2 activation, whereas suppression of Gbeta2 expression in C2C12 myotubes enhances NRG-mediated ERK1/2 activation and c-fos transcription. These results suggest that expression of Gbeta protein negatively regulates NRG-stimulated gene transcription in cultured myotubes. Taken together, our observations provide evidence that specific heterotrimeric G proteins regulate NRG-mediated signaling and gene transcription during rat muscle development.
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Affiliation(s)
- K-C Lok
- Department of Biochemistry, Biotechnology Research Institute and Molecular Neuroscience Center, Hong Kong University of Science and Technology, Clear Water Bay Road, Hong Kong, China
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35
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Ravel-Chapuis A, Vandromme M, Thomas JL, Schaeffer L. Postsynaptic chromatin is under neural control at the neuromuscular junction. EMBO J 2007; 26:1117-28. [PMID: 17304221 PMCID: PMC1852850 DOI: 10.1038/sj.emboj.7601572] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 01/04/2007] [Indexed: 12/25/2022] Open
Abstract
In adult skeletal muscle, the nicotinic acetylcholine receptor (AChR) specifically accumulates at the neuromuscular junction, to allow neurotransmission. This clustering is paralleled by a compartmentalization of AChR genes expression to subsynaptic nuclei, which acquire a unique gene expression program and a specific morphology in response to neural cues. Our results demonstrate that neural agrin-dependent reprogramming of myonuclei involves chromatin remodelling, histone hyperacetylation and histone hyperphosphorylation. Activation of AChR genes in subsynaptic nuclei is mediated by the transcription factor GABP. Here we demonstrate that upon activation, GABP recruits the histone acetyl transferase (HAT) p300 on the AChR epsilon subunit promoter, whereas it rather recruits the histone deacetylase HDAC1 when the promoter is not activated. Moreover, the HAT activity of p300 is required in vivo for AChR expression. GABP therefore couples chromatin hyperacetylation and AChR activation by neural factors in subsynaptic nuclei.
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Affiliation(s)
- Aymeric Ravel-Chapuis
- Equipe Différenciation Neuromusculaire; IFR128; UMR5161; ENS Lyon; CNRS; INRA; Université de Lyon; Lyon Cedex, France
| | - Marie Vandromme
- Equipe Différenciation Neuromusculaire; IFR128; UMR5161; ENS Lyon; CNRS; INRA; Université de Lyon; Lyon Cedex, France
| | - Jean-Luc Thomas
- Equipe Différenciation Neuromusculaire; IFR128; UMR5161; ENS Lyon; CNRS; INRA; Université de Lyon; Lyon Cedex, France
| | - Laurent Schaeffer
- Equipe Différenciation Neuromusculaire; IFR128; UMR5161; ENS Lyon; CNRS; INRA; Université de Lyon; Lyon Cedex, France
- Equipe Différenciation Neuromusculaire; IFR128; UMR5161; ENS Lyon; CNRS; INRA; Université de Lyon; 46 allée d'Italie, 69364 Lyon Cedex 07, France. Tel.: +33 4 72 72 85 73; Fax: +33 4 72 72 80 80; E-mail:
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36
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Chakkalakal JV, Michel SA, Chin ER, Michel RN, Jasmin BJ. Targeted inhibition of Ca2+/calmodulin signaling exacerbates the dystrophic phenotype in mdx mouse muscle. Hum Mol Genet 2006; 15:1423-35. [PMID: 16551657 DOI: 10.1093/hmg/ddl065] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
In this study, we crossbred mdx mice with transgenic mice expressing a small peptide inhibitor for calmodulin (CaM), known as the CaM-binding protein (CaMBP), driven by the slow fiber-specific troponin I slow promoter. This strategy allowed us to determine the impact of interfering with Ca(2+)/CaM-based signaling in dystrophin-deficient slow myofibers. Consistent with impairments in the Ca(2+)/CaM-regulated enzymes calcineurin and Ca(2+)/CaM-dependent kinase, the nuclear accumulation of nuclear factor of activated T-cell c1 and myocyte enhancer factor 2C was reduced in slow fibers from mdx/CaMBP mice. We also detected significant reductions in the levels of peroxisome proliferator gamma co-activator 1alpha and GA-binding protein alpha mRNAs in slow fiber-rich soleus muscles of mdx/CaMBP mice. In parallel, we observed significantly lower expression of myosin heavy chain I mRNA in mdx/CaMBP soleus muscles. This correlated with fiber-type shifts towards a faster phenotype. Examination of mdx/CaMBP slow muscle fibers revealed significant reductions in A-utrophin, a therapeutically relevant protein that can compensate for the lack of dystrophin in skeletal muscle. In accordance with lower levels of A-utrophin, we noted a clear exacerbation of the dystrophic phenotype in mdx/CaMBP slow fibers as exemplified by several pathological indices. These results firmly establish Ca(2+)/CaM-based signaling as key to regulating expression of A-utrophin in muscle. Furthermore, this study illustrates the therapeutic potential of using targets of Ca(2+)/CaM-based signaling as a strategy for treating Duchenne muscular dystrophy (DMD). Finally, our results further support the concept that strategies aimed at promoting the slow oxidative myofiber program in muscle may be effective in altering the relentless progression of DMD.
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Affiliation(s)
- Joe V Chakkalakal
- Department of Cellular and Molecular Medicine, Centre for Neuromuscular Diseases, Faculty of Medicine, University of Ottawa, Ottawa, Ont., Canada K1H 8M5
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37
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Jaworski A, Burden SJ. Neuromuscular synapse formation in mice lacking motor neuron- and skeletal muscle-derived Neuregulin-1. J Neurosci 2006; 26:655-61. [PMID: 16407563 PMCID: PMC6674415 DOI: 10.1523/jneurosci.4506-05.2006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The localization of acetylcholine receptors (AChRs) to the vertebrate neuromuscular junction is mediated, in part, through selective transcription of AChR subunit genes in myofiber subsynaptic nuclei. Agrin and the muscle-specific receptor tyrosine kinase, MuSK, have critical roles in synapse-specific transcription, because AChR genes are expressed uniformly in mice lacking either agrin or MuSK. Several lines of evidence suggest that agrin and MuSK stimulate synapse-specific transcription indirectly by regulating the distribution of other cell surface ligands, which stimulate a pathway for synapse-specific gene expression. This putative secondary signal for directing AChR gene expression to synapses is not known, but Neuregulin-1 (Nrg-1), primarily based on its presence at synapses and its ability to induce AChR gene expression in vitro, has been considered a good candidate. To study the role of Nrg-1 at neuromuscular synapses, we inactivated nrg-1 in motor neurons, skeletal muscle, or both cell types, using mice that express Cre recombinase selectively in developing motor neurons or in developing skeletal myofibers. We find that AChRs are clustered at synapses and that synapse-specific transcription is normal in mice lacking Nrg-1 in motor neurons, myofibers, or both cell types. These data indicate that Nrg-1 is dispensable for clustering AChRs and activating AChR genes in subsynaptic nuclei during development and suggest that these aspects of postsynaptic differentiation are dependent on Agrin/MuSK signaling without a requirement for a secondary signal.
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MESH Headings
- Agrin/physiology
- Animals
- Cell Differentiation
- Diaphragm/embryology
- Diaphragm/innervation
- ErbB Receptors/metabolism
- Genes, Reporter
- Integrases/genetics
- Integrases/metabolism
- Intercostal Muscles/embryology
- Intercostal Muscles/innervation
- Mice
- Mice, Knockout
- Motor Neurons/metabolism
- Motor Neurons/ultrastructure
- Muscle Fibers, Skeletal/metabolism
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal/embryology
- Muscle, Skeletal/innervation
- Nerve Tissue Proteins/deficiency
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/physiology
- Neuregulin-1
- Neuromuscular Junction/embryology
- Neuromuscular Junction/physiology
- Neuromuscular Junction/ultrastructure
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Receptor Protein-Tyrosine Kinases/biosynthesis
- Receptor Protein-Tyrosine Kinases/genetics
- Receptor Protein-Tyrosine Kinases/physiology
- Receptor, ErbB-2/metabolism
- Receptor, ErbB-4
- Receptors, Cholinergic/biosynthesis
- Receptors, Cholinergic/genetics
- Receptors, Cholinergic/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Deletion
- Viral Proteins/genetics
- Viral Proteins/metabolism
- beta-Galactosidase/analysis
- beta-Galactosidase/genetics
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Affiliation(s)
- Alexander Jaworski
- Molecular Neurobiology Program, Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, New York 10016, USA
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38
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Miura P, Jasmin BJ. Utrophin upregulation for treating Duchenne or Becker muscular dystrophy: how close are we? Trends Mol Med 2006; 12:122-9. [PMID: 16443393 DOI: 10.1016/j.molmed.2006.01.002] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2005] [Revised: 12/16/2005] [Accepted: 01/13/2006] [Indexed: 12/30/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle-wasting disorder for which there is currently no effective treatment. This disorder is caused by mutations or deletions in the gene encoding dystrophin that prevent expression of dystrophin at the sarcolemma. A promising pharmacological treatment for DMD aims to increase levels of utrophin, a homolog of dystrophin, in muscle fibers of affected patients to compensate for the absence of dystrophin. Here, we review recent developments in our understanding of the regulatory pathways that govern utrophin expression, and highlight studies that have used activators of these pathways to alleviate the dystrophic symptoms in DMD animal models. The results of these preclinical studies are promising and bring us closer to implementing appropriate utrophin-based drug therapies for DMD patients.
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Affiliation(s)
- Pedro Miura
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario K1H 8M5, Canada
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Abstract
The neuromuscular junction (NMJ) is a complex structure that serves to efficiently communicate the electrical impulse from the motor neuron to the skeletal muscle to signal contraction. Over the last 200 years, technological advances in microscopy allowed visualization of the existence of a gap between the motor neuron and skeletal muscle that necessitated the existence of a messenger, which proved to be acetylcholine. Ultrastructural analysis identified vesicles in the presynaptic nerve terminal, which provided a beautiful structural correlate for the quantal nature of neuromuscular transmission, and the imaging of synaptic folds on the muscle surface demonstrated that specializations of the underlying protein scaffold were required. Molecular analysis in the last 20 years has confirmed the preferential expression of synaptic proteins, which is guided by a precise developmental program and maintained by signals from nerve. Although often overlooked, the Schwann cell that caps the NMJ and the basal lamina is proving to be critical in maintenance of the junction. Genetic and autoimmune disorders are known that compromise neuromuscular transmission and provide further insights into the complexities of NMJ function as well as the subtle differences that exist among NMJ that may underlie the differential susceptibility of muscle groups to neuromuscular transmission diseases. In this review we summarize the synaptic physiology, architecture, and variations in synaptic structure among muscle types. The important roles of specific signaling pathways involved in NMJ development and acetylcholine receptor (AChR) clustering are reviewed. Finally, genetic and autoimmune disorders and their effects on NMJ architecture and neuromuscular transmission are examined.
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Affiliation(s)
- Benjamin W Hughes
- Department of Neurology, Case Western University School of Medicine, 10900 Euclid Avenue, Cleveland, OH 44106, USA
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Sewry CA, Nowak KJ, Ehmsen JT, Davies KE. A and B utrophin in human muscle and sarcolemmal A-utrophin associated with tumours. Neuromuscul Disord 2005; 15:779-85. [PMID: 16198105 DOI: 10.1016/j.nmd.2005.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2005] [Revised: 06/15/2005] [Accepted: 08/02/2005] [Indexed: 11/16/2022]
Abstract
Utrophin is an autosomal homologue of dystrophin, abnormal expression of which is responsible for X-linked Duchenne and Becker muscular dystrophy. In normal mature muscle utrophin is confined to blood vessels, nerves and myotendinous and neuromuscular junctions. When dystrophin is absent utrophin is abundant on the sarcolemma. This has raised the possibility that up-regulation of utrophin may be of therapeutic benefit. Two full-length transcripts of utrophin, A and B, have been identified, which are regulated by alternatively spliced 5' promoters. In dystrophic mouse muscle, the A isoform is present on the sarcolemma, whereas the B form is confined to blood vessels. We show here using immunohistochemistry and human isoform-specific antibodies that A- and B-utrophin localisation is the same in human muscle. The A isoform is present on the sarcolemma of foetal human muscle fibres, regenerating fibres, fibres deficient in dystrophin and on blood vessels and neuromuscular junctions. B-utrophin is only detected on blood vessels. We also show that muscle adjacent to some soft tissue tumours shows increased sarcolemmal utrophin-A, showing that utrophin and dystrophin can simultaneously localise to the sarcolemma and raising the possibility that factor(s) from the tumour cells or accompanying inflammatory cells may have a role in regulating utrophin.
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Affiliation(s)
- C A Sewry
- Department of Histopathology, Centre for Inherited Neuromuscular Disorders, Robert Jones and Agnes Hunt Orthopaedic and District Hospital, NHS Trust, Oswestry SY10 7AG, UK.
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Angus LM, Chakkalakal JV, Méjat A, Eibl JK, Bélanger G, Megeney LA, Chin ER, Schaeffer L, Michel RN, Jasmin BJ. Calcineurin-NFAT signaling, together with GABP and peroxisome PGC-1α, drives utrophin gene expression at the neuromuscular junction. Am J Physiol Cell Physiol 2005; 289:C908-17. [PMID: 15930144 DOI: 10.1152/ajpcell.00196.2005] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
We examined whether calcineurin-NFAT (nuclear factors of activated T cells) signaling plays a role in specifically directing the expression of utrophin in the synaptic compartment of muscle fibers. Immunofluorescence experiments revealed the accumulation of components of the calcineurin-NFAT signaling cascade within the postsynaptic membrane domain of the neuromuscular junction. RT-PCR analysis using synaptic vs. extrasynaptic regions of muscle fibers confirmed these findings by showing an accumulation of calcineurin transcripts within the synaptic compartment. We also examined the effect of calcineurin on utrophin gene expression. Pharmacological inhibition of calcineurin in mice with either cyclosporin A or FK506 resulted in a marked decrease in utrophin A expression at synaptic sites, whereas constitutive activation of calcineurin had the opposite effect. Mutation of the previously identified NFAT binding site in the utrophin A promoter region, followed by direct gene transfer studies in mouse muscle, led to an inhibition in the synaptic expression of a lacZ reporter gene construct. Transfection assays performed with cultured myogenic cells indicated that calcineurin acted additively with GA binding protein (GABP) to transactivate utrophin A gene expression. Because both GABP- and calcineurin-mediated pathways are targeted by peroxisome proliferator-activated receptor-γ coactivator-1α (PGC-1α), we examined whether this coactivator contributes to utrophin gene expression. In vitro and in vivo transfection experiments showed that PGC-1α alone induces transcription from the utrophin A promoter. Interestingly, this induction is largely potentiated by coexpression of PGC-1α with GABP. Together, these studies indicate that the synaptic expression of utrophin is also driven by calcineurin-NFAT signaling and occurs in conjunction with signaling events that involve GABP and PGC-1α.
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Affiliation(s)
- Lindsay M Angus
- Department of Cellular and Molecular Medicine, and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ontario, Canada K1H 8M5
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Tsuchimochi K, Yagishita N, Yamasaki S, Amano T, Kato Y, Kawahara KI, Aratani S, Fujita H, Ji F, Sugiura A, Izumi T, Sugamiya A, Maruyama I, Fukamizu A, Komiya S, Nishioka K, Nakajima T. Identification of a crucial site for synoviolin expression. Mol Cell Biol 2005; 25:7344-56. [PMID: 16055742 PMCID: PMC1190266 DOI: 10.1128/mcb.25.16.7344-7356.2005] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Synoviolin is an E3 ubiquitin ligase localized in the endoplasmic reticulum (ER) and serving as ER-associated degradation system. Analysis of transgenic mice suggested that synoviolin gene dosage is implicated in the pathogenesis of arthropathy. Complete deficiency of synoviolin is fatal embryonically. Thus, alternation of Synoviolin could cause breakdown of ER homeostasis and consequently lead to disturbance of cellular homeostasis. Hence, the expression level of Synoviolin appears to be important for its biological role in cellular homeostasis under physiological and pathological conditions. To examine the control of protein level, we performed promoter analysis to determine transcriptional regulation. Here we characterize the role of synoviolin transcription in cellular homeostasis. The Ets binding site (EBS), termed EBS-1, from position -76 to -69 of the proximal promoter, is responsible for synoviolin expression in vivo and in vitro. Interestingly, transfer of EBS-1 decoy into NIH 3T3 cells conferred not only the repression of synoviolin gene expression but also a decrease in cell number. Fluorescence-activated cell sorter analysis using annexin V staining confirmed the induction of apoptosis by EBS-1 decoy and demonstrated recovery of apoptosis by overexpression of Synoviolin. Our results suggest that transcriptional regulation of synoviolin via EBS-1 plays an important role in cellular homeostasis. Our study provides novel insight into the transcriptional regulation for cellular homeostasis.
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Affiliation(s)
- Kaneyuki Tsuchimochi
- Department of Genomic Science, Institute of Medical Science, St. Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
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Miura P, Thompson J, Chakkalakal JV, Holcik M, Jasmin BJ. The utrophin A 5'-untranslated region confers internal ribosome entry site-mediated translational control during regeneration of skeletal muscle fibers. J Biol Chem 2005; 280:32997-3005. [PMID: 16061482 DOI: 10.1074/jbc.m503994200] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Utrophin up-regulation in muscle fibers of Duchenne muscular dystrophy patients represents a potential therapeutic strategy. It is thus important to delineate the regulatory events presiding over utrophin in muscle in attempts to develop pharmacological interventions aimed at increasing utrophin expression. A number of studies have now shown that under several experimental conditions, the abundance of utrophin is increased without a corresponding elevation in its mRNA. Here, we examine whether utrophin expression is regulated at the translational level in regenerating muscle fibers. Treatment of mouse tibialis anterior muscles with cardiotoxin to induce muscle degeneration/regeneration led to a large (approximately 14-fold) increase in the levels of utrophin A with a modest change in expression of its transcript (40%). Isolation of the mouse utrophin A 5'-untranslated region (UTR) revealed that it is relatively long with a predicted high degree of secondary structure. In control muscles, the 5'-UTR of utrophin A caused an inhibition upon translation of a reporter protein. Strikingly, this inhibition was removed during regeneration, indicating that expression of utrophin A in regenerating muscles is translationally regulated via its 5'-UTR. Using bicistronic reporter vectors, we observed that this translational effect involves an internal ribosome entry site in the utrophin A 5'-UTR. Thus, internal ribosome entry site-mediated translation of utrophin A can, at least partially, account for the discordant expression of utrophin A protein and transcript in regenerating muscle. These findings provide a novel target for up-regulating levels of utrophin A in Duchenne muscular dystrophy muscle fibers via pharmacological interventions.
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MESH Headings
- 5' Untranslated Regions
- Animals
- Binding Sites
- Blotting, Northern
- Blotting, Western
- Cells, Cultured
- Cobra Cardiotoxin Proteins/metabolism
- Gene Expression Regulation
- Genes, Reporter
- Genetic Vectors
- Mice
- Mice, Inbred C57BL
- Microscopy, Fluorescence
- Models, Genetic
- Muscle Fibers, Skeletal/metabolism
- Muscle, Skeletal/metabolism
- Muscles/metabolism
- Plasmids/metabolism
- Protein Biosynthesis
- Protein Structure, Secondary
- RNA/metabolism
- RNA, Messenger/metabolism
- Regeneration
- Reverse Transcriptase Polymerase Chain Reaction
- Ribosomes/metabolism
- Up-Regulation
- Utrophin/chemistry
- Utrophin/genetics
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Affiliation(s)
- Pedro Miura
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
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Stocksley MA, Chakkalakal JV, Bradford A, Miura P, De Repentigny Y, Kothary R, Jasmin BJ. A 1.3 kb promoter fragment confers spatial and temporal expression of utrophin A mRNA in mouse skeletal muscle fibers. Neuromuscul Disord 2005; 15:437-49. [PMID: 15907291 DOI: 10.1016/j.nmd.2005.03.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 03/02/2005] [Accepted: 03/04/2005] [Indexed: 10/25/2022]
Abstract
Upregulation of utrophin in muscle is currently being examined as a potential therapy for Duchenne muscular dystrophy patients. In this context, we generated transgenic mice harboring a 1.3 kb human utrophin A promoter fragment driving expression of the lacZ gene. Characterization of reporter expression during postnatal muscle development revealed that the levels and localization of beta-galactosidase parallel expression of utrophin A transcripts. Moreover, we noted that the utrophin A promoter is more active in slow soleus muscles. Additionally, expression of the reporter gene was regulated during muscle regeneration in a manner similar to utrophin A transcripts. Together, these results show that the utrophin A promoter-lacZ construct mirrors expression of utrophin A mRNAs indicating that this utrophin A promoter fragment confers temporal and spatial patterns of expression in skeletal muscle. This transgenic mouse will be valuable as an in vivo model for developing and testing molecules aimed at increasing utrophin A expression.
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MESH Headings
- Animals
- Animals, Newborn
- Female
- Gene Expression
- Genes, Reporter
- Genetic Therapy
- Lac Operon
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Muscle Fibers, Fast-Twitch/physiology
- Muscle Fibers, Slow-Twitch/physiology
- Muscle, Skeletal/cytology
- Muscle, Skeletal/physiology
- Muscular Dystrophy, Duchenne/physiopathology
- Muscular Dystrophy, Duchenne/therapy
- Neuromuscular Junction/physiology
- Promoter Regions, Genetic/genetics
- RNA, Messenger/analysis
- Regeneration/physiology
- Utrophin/genetics
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Affiliation(s)
- Mark A Stocksley
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, 451 Smyth Road, Ottawa, Ont., Canada K1H 8M5
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Chakkalakal JV, Thompson J, Parks RJ, Jasmin BJ. Molecular, cellular, and pharmacological therapies for Duchenne/Becker muscular dystrophies. FASEB J 2005; 19:880-91. [PMID: 15923398 DOI: 10.1096/fj.04-1956rev] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although the molecular defect causing Duchenne/Becker muscular dystrophy (DMD/BMD) was identified nearly 20 years ago, the development of effective therapeutic strategies has nonetheless remained a daunting challenge. Over the years, a variety of different approaches have been explored in an effort to compensate for the lack of the DMD gene product called dystrophin. This review not only presents some of the most promising molecular, cellular, and pharmacological strategies but also highlights some issues that need to be addressed before considering their implementation. Specifically, we describe current strategies being developed to exogenously deliver healthy copies of the dystrophin gene to dystrophic muscles. We present the findings of several studies that have focused on repairing the mutant dystrophin gene using various approaches. We include a discussion of cell-based therapies that capitalize on the use of myoblast or stem cell transfer. Finally, we summarize the results of several studies that may eventually lead to the development of appropriate drug-based therapies. In this context, we review our current knowledge of the mechanisms regulating expression of utrophin, the autosomal homologue of dystrophin. Given the complexity associated with the dystrophic phenotype, it appears likely that a combinatorial approach involving different therapeutic strategies will be necessary for the appropriate management and eventual treatment of this devastating neuromuscular disease.
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Affiliation(s)
- Joe V Chakkalakal
- Department of Cellular and Molecular Medicine and Centre for Neuromuscular Disease, Faculty of Medicine, University of Ottawa, Ontario, Canada
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Ngo ST, Balke C, Phillips WD, Noakes PG. Neuregulin potentiates agrin-induced acetylcholine receptor clustering in myotubes. Neuroreport 2005; 15:2501-5. [PMID: 15538183 DOI: 10.1097/00001756-200411150-00014] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Agrin and neuregulin (HRG-beta1) play complementary roles in synapse formation. While HRG-beta1 induces transcriptional up-regulation of postsynaptic proteins, here we present evidence that it can potentiate agrin-induced acetylcholine receptor (AChR) clustering in C2 myotubes. Agrin induced maximal AChR clustering in 4 h. HRG-beta1 treatment for 4 h produced no increase over basal AChR cluster numbers. When myotubes were treated for 4 h with 100 pM agrin, HRG-beta1 augmented AChR cluster numbers by 2-fold compared to myotubes treated with 100 pM agrin alone. Thus, HRG-beta1 can potentiate agrin-induced AChR clustering.
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Affiliation(s)
- Shyuan T Ngo
- School of Biomedical Sciences, University of Queensland, St. Lucia 4072 QLD, Australia
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O'Leary DA, Pritchard MA, Xu D, Kola I, Hertzog PJ, Ristevski S. Tissue-specific overexpression of the HSA21 gene GABPalpha: implications for DS. Biochim Biophys Acta Mol Basis Dis 2005; 1739:81-7. [PMID: 15607120 DOI: 10.1016/j.bbadis.2004.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2004] [Revised: 09/07/2004] [Accepted: 09/08/2004] [Indexed: 11/15/2022]
Abstract
The ETS transcription factor GABPalpha is encoded by a gene on HSA21 and interacts with an ankyrin repeat-containing beta subunit to form the GABP complex. GABP regulates expression of genes involved in mitochondrial respiration and neuromuscular signalling. When GABPalpha mRNA is overexpressed in human DS fibroblast cell lines, or by tranfection in NIH3T3 cells, no increase in protein level is detected. However, increased Gabpalpha gene dosage in the Ts65Dn segmental trisomy mouse model of DS (DS) results in elevated Gabpalpha protein levels in brain and skeletal muscle only. These findings suggest that GABPalpha protein levels are tightly regulated in a tissue-specific manner, and consequently GABP may play a role in DS pathologies in tissues where GABPalpha protein levels are elevated.
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Affiliation(s)
- Debra A O'Leary
- Centre for Functional Genomics and Human Disease, Monash Institute of Reproduction and Development, Monash University, Clayton, Victoria 3168, Australia
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Gramolini AO, Kislinger T, Asahi M, Li W, Emili A, MacLennan DH. Sarcolipin retention in the endoplasmic reticulum depends on its C-terminal RSYQY sequence and its interaction with sarco(endo)plasmic Ca(2+)-ATPases. Proc Natl Acad Sci U S A 2004; 101:16807-12. [PMID: 15556994 PMCID: PMC534750 DOI: 10.1073/pnas.0407815101] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sarcolipin (SLN) and phospholamban (PLN) are effective inhibitors of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA). These homologous proteins differ at their N and C termini: the C-terminal Met-Leu-Leu in PLN is replaced by Arg-Ser-Tyr-Gln-Tyr in SLN. The role of the C-terminal sequence of SLN tagged N-terminally with the FLAG epitope (NF-SLN) in endoplasmic reticulum (ER) retention was investigated by transfecting human embryonic kidney-293 cells with cDNAs encoding NF-SLN or a series of NF-SLN mutants in which C-terminal amino acids were deleted progressively. Immunofluorescence and immunoblotting of transfected cells by using anti-FLAG antibodies indicated that NF-SLN and PLN tagged at its N terminus with the FLAG epitope, even when overexpressed, were restricted to the ER. However, C-terminal truncation deletions of SLN, which lacked RSYQY, were not localized to ER and did not inhibit Ca(2+)-dependent Ca2+ uptake by SERCA. The shortest deletion constructs, NF-SLN 1-22 and NF-SLN 1-23, did not express stable protein products. However, all NF-SLN cDNA constructs, including NF-SLN 1-22 and NF-SLN 1-23, were expressed stably and localized to the ER when they were coexpressed with SERCA2a. These results show that NF-SLN subcellular distribution depends on SERCA coexpression and on its luminal, C-terminal RSYQY sequence. By using immunoprecipitation and MS, glucose-regulated protein 78/BiP and glucose-regulated protein 94 were identified as proteins that interact with NF-SLN through the RSYQY sequence. Thus, in the absence of SERCA, retention of NF-SLN in the ER is mediated through its association with other components through the C-terminal RSYQY sequence.
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Affiliation(s)
- Anthony O Gramolini
- Banting and Best Department of Medical Research, University of Toronto, Charles H. Best Institute, 112 College Street, Toronto, ON, Canada M5G 1L6
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Krag TOB, Bogdanovich S, Jensen CJ, Fischer MD, Hansen-Schwartz J, Javazon EH, Flake AW, Edvinsson L, Khurana TS. Heregulin ameliorates the dystrophic phenotype in mdx mice. Proc Natl Acad Sci U S A 2004; 101:13856-60. [PMID: 15365169 PMCID: PMC518764 DOI: 10.1073/pnas.0405972101] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Duchenne's muscular dystrophy (DMD) is a fatal neuromuscular disease caused by absence of dystrophin. Utrophin is a chromosome 6-encoded dystrophin-related protein (DRP), sharing functional motifs with dystrophin. Utrophin's ability to compensate for dystrophin during development and when transgenically overexpressed has provided an important impetus for identifying activators of utrophin expression. The utrophin promoter A is transcriptionally regulated in part by heregulin-mediated, extracellular signal-related kinase-dependent activation of the GABP(alpha/beta) transcription factor complex. Therefore, this pathway offers a potential mechanism to modulate utrophin expression in muscle. We tested the ability of heregulin to improve the dystrophic phenotype in the mdx mouse model of DMD. Intraperitoneal injections of a small peptide encoding the epidermal growth factor-like region of heregulin ectodomain for 3 months in vivo resulted in up-regulation of utrophin, a marked improvement in the mechanical properties of muscle as evidenced by resistance to eccentric contraction mediated damage, and a reduction of muscle pathology. The amelioration of dystrophic phenotype by heregulin-mediated utrophin up-regulation offers a pharmacological therapeutic modality and obviates many of the toxicity and delivery issues associated with viral vector-based gene therapy for DMD.
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Affiliation(s)
- Thomas O B Krag
- Department of Physiology and Pennsylvania Muscle Institute, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA.
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50
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Jacobson C, Duggan D, Fischbach G. Neuregulin induces the expression of transcription factors and myosin heavy chains typical of muscle spindles in cultured human muscle. Proc Natl Acad Sci U S A 2004; 101:12218-23. [PMID: 15302938 PMCID: PMC514402 DOI: 10.1073/pnas.0404240101] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Neuregulin (NRG) (also known as ARIA, GGF, and other names) is a heparin sulfate proteoglycan secreted into the neuromuscular junction by innervating motor and sensory neurons. An integral part of synapse formation, we have analyzed NRG-induced changes in gene expression over 48 h in primary human myotubes. We show that in addition to increasing the expression of acetylcholine receptors on the myotube surface, NRG treatment results in a transient increase of several members of the early growth response (Egr) family of transcription factors. Three Egrs, Egr1, -2, and -3, are induced within the first hour of NRG treatment, with Egr1 and -3 RNA levels showing the most significant increases of approximately 9- and 16-fold, respectively. Also noted was a corresponding increase in protein levels for both of these transcription factors. Previous literature indicates that Egr3 expression is required for the formation of muscle spindle fibers, sensory organs that are distinct from skeletal muscle contractile fibers. At the molecular level, muscle spindle fibers express a unique subset of myosin heavy chains. Two isoforms of the myosin heavy chain, the slow development and neonatal, were found to be increased in our myotube cultures after 48 h of treatment with NRG. Taken together, these results indicate that not only can NRG induce the expression of a transcription factor key to spindle fiber development (Egr3), but that a portion of this developmental process can be replicated in vitro.
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Affiliation(s)
- Christian Jacobson
- Microarray Unit, Genetics and Genomics Section, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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