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Careccia G, Mangiavini L, Cirillo F. Regulation of Satellite Cells Functions during Skeletal Muscle Regeneration: A Critical Step in Physiological and Pathological Conditions. Int J Mol Sci 2023; 25:512. [PMID: 38203683 PMCID: PMC10778731 DOI: 10.3390/ijms25010512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 12/20/2023] [Accepted: 12/28/2023] [Indexed: 01/12/2024] Open
Abstract
Skeletal muscle regeneration is a complex process involving the generation of new myofibers after trauma, competitive physical activity, or disease. In this context, adult skeletal muscle stem cells, also known as satellite cells (SCs), play a crucial role in regulating muscle tissue homeostasis and activating regeneration. Alterations in their number or function have been associated with various pathological conditions. The main factors involved in the dysregulation of SCs' activity are inflammation, oxidative stress, and fibrosis. This review critically summarizes the current knowledge on the role of SCs in skeletal muscle regeneration. It examines the changes in the activity of SCs in three of the most common and severe muscle disorders: sarcopenia, muscular dystrophy, and cancer cachexia. Understanding the molecular mechanisms involved in their dysregulations is essential for improving current treatments, such as exercise, and developing personalized approaches to reactivate SCs.
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Affiliation(s)
- Giorgia Careccia
- Department of Biosciences, University of Milan, 20133 Milan, Italy;
| | - Laura Mangiavini
- IRCCS Istituto Ortopedico Galeazzi, 20161 Milan, Italy;
- Department of Biomedical Sciences for Health, University of Milan, 20133 Milan, Italy
| | - Federica Cirillo
- IRCCS Policlinico San Donato, 20097 San Donato Milanese, Italy
- Institute for Molecular and Translational Cardiology (IMTC), 20097 San Donato Milanese, Italy
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2
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Saito A, Matsui S, Chino A, Sato S, Takeshita N. Discovery and pharmacological characterization of novel positive allosteric modulators acting on skeletal muscle-type nicotinic acetylcholine receptors. Biochem Biophys Res Commun 2023; 668:27-34. [PMID: 37235916 DOI: 10.1016/j.bbrc.2023.04.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023]
Abstract
Skeletal muscle-type nicotinic acetylcholine receptors (m-nAChRs) are ligand-gated ion channels that open after activation by ACh and whose signals cause muscle contraction. Defects in neurotransmission are reported in disorders such as myasthenia gravis (MG) and congenital myasthenia syndromes (CMS). Although treatments for these disorders exist, therapies which significantly increase muscle strength have yet to be reported. Positive allosteric modulators (PAMs), which promote ACh signaling through AChRs, are expected to be promising therapeutic agents. In this study, we identified an m-nAChR PAM called AS3513678 by high-throughput screening using human myotube cells and modified it to obtain novel compounds (AS3566987 and AS3580239) that showed even stronger PAM activity. AS3580239 caused a leftward shift in the ACh concentration-response curve and was 14.0-fold potent at 10 μM compared with vehicle. Next, we examined the effect of AS3580239 on electrically-induced isometric contraction of the extensor digitorum longus (EDL) muscle in wild-type (WT) and MG model rats. AS3580239 enhanced EDL muscle contraction in both WT and MG model rats at 30 μM. These data suggest that AS3580239 improved neurotransmission and enhanced muscle strength. Thus, m-nAChR PAMs may be a useful treatment for neuromuscular diseases.
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Affiliation(s)
- Asako Saito
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.
| | - Shigeo Matsui
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Ayaka Chino
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Shota Sato
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Nobuaki Takeshita
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
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3
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Sokolova AV, Domnina AP, Mikhailov VM. Accumulation of Dystrophin-Positive Muscle Fibers and Improvement of Neuromuscular Junctions in mdx Mouse Muscles after Bone Marrow Transplantation under Different Conditions. Int J Mol Sci 2023; 24:ijms24108892. [PMID: 37240237 DOI: 10.3390/ijms24108892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 05/13/2023] [Accepted: 05/14/2023] [Indexed: 05/28/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscular disorder caused by mutations in the dystrophin gene. It leads to respiratory and cardiac failure and premature death at a young age. Although recent studies have greatly deepened the understanding of the primary and secondary pathogenetic mechanisms of DMD, an effective treatment remains elusive. In recent decades, stem cells have emerged as a novel therapeutic product for a variety of diseases. In this study, we investigated nonmyeloablative bone marrow cell (BMC) transplantation as a method of cell therapy for DMD in an mdx mouse model. By using BMC transplantation from GFP-positive mice, we confirmed that BMCs participate in the muscle restoration of mdx mice. We analyzed both syngeneic and allogeneic BMC transplantation under different conditions. Our data indicated that 3 Gy X-ray irradiation with subsequent BMC transplantation improved dystrophin synthesis and the structure of striated muscle fibers (SMFs) in mdx mice as well as decreasing the death rate of SMFs. In addition, we observed the normalization of neuromuscular junctions (NMJs) in mdx mice after nonmyeloablative BMC transplantation. In conclusion, we demonstrated that nonmyeloablative BMC transplantation could be considered a method for DMD treatment.
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Affiliation(s)
| | - Alisa P Domnina
- Institute of Cytology, Russian Academy of Sciences, 194064 Saint-Petersburg, Russia
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4
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Dubuisson N, Versele R, Planchon C, Selvais CM, Noel L, Abou-Samra M, Davis-López de Carrizosa MA. Histological Methods to Assess Skeletal Muscle Degeneration and Regeneration in Duchenne Muscular Dystrophy. Int J Mol Sci 2022; 23:16080. [PMID: 36555721 PMCID: PMC9786356 DOI: 10.3390/ijms232416080] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 12/09/2022] [Accepted: 12/14/2022] [Indexed: 12/23/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive disease caused by the loss of function of the protein dystrophin. This protein contributes to the stabilisation of striated cells during contraction, as it anchors the cytoskeleton with components of the extracellular matrix through the dystrophin-associated protein complex (DAPC). Moreover, absence of the functional protein affects the expression and function of proteins within the DAPC, leading to molecular events responsible for myofibre damage, muscle weakening, disability and, eventually, premature death. Presently, there is no cure for DMD, but different treatments help manage some of the symptoms. Advances in genetic and exon-skipping therapies are the most promising intervention, the safety and efficiency of which are tested in animal models. In addition to in vivo functional tests, ex vivo molecular evaluation aids assess to what extent the therapy has contributed to the regenerative process. In this regard, the later advances in microscopy and image acquisition systems and the current expansion of antibodies for immunohistological evaluation together with the development of different spectrum fluorescent dyes have made histology a crucial tool. Nevertheless, the complexity of the molecular events that take place in dystrophic muscles, together with the rise of a multitude of markers for each of the phases of the process, makes the histological assessment a challenging task. Therefore, here, we summarise and explain the rationale behind different histological techniques used in the literature to assess degeneration and regeneration in the field of dystrophinopathies, focusing especially on those related to DMD.
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Affiliation(s)
- Nicolas Dubuisson
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
- Neuromuscular Reference Center, Cliniques Universitaires Saint-Luc (CUSL), Avenue Hippocrate 10, 1200 Brussels, Belgium
| | - Romain Versele
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Chloé Planchon
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Camille M. Selvais
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Laurence Noel
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - Michel Abou-Samra
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
| | - María A. Davis-López de Carrizosa
- Endocrinology, Diabetes and Nutrition Unit, Institute of Experimental and Clinical Research, Medical Sector, Université Catholique de Louvain (UCLouvain), Avenue Hippocrate 55, 1200 Brussels, Belgium
- Departamento de Fisiología, Facultad de Biología, Universidad de Sevilla, 41012 Seville, Spain
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5
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Pharmacological inhibition of HDAC6 improves muscle phenotypes in dystrophin-deficient mice by downregulating TGF-β via Smad3 acetylation. Nat Commun 2022; 13:7108. [PMID: 36402791 PMCID: PMC9675748 DOI: 10.1038/s41467-022-34831-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Accepted: 11/01/2022] [Indexed: 11/21/2022] Open
Abstract
The absence of dystrophin in Duchenne muscular dystrophy disrupts the dystrophin-associated glycoprotein complex resulting in skeletal muscle fiber fragility and atrophy, associated with fibrosis as well as microtubule and neuromuscular junction disorganization. The specific, non-conventional cytoplasmic histone deacetylase 6 (HDAC6) was recently shown to regulate acetylcholine receptor distribution and muscle atrophy. Here, we report that administration of the HDAC6 selective inhibitor tubastatin A to the Duchenne muscular dystrophy, mdx mouse model increases muscle strength, improves microtubule, neuromuscular junction, and dystrophin-associated glycoprotein complex organization, and reduces muscle atrophy and fibrosis. Interestingly, we found that the beneficial effects of HDAC6 inhibition involve the downregulation of transforming growth factor beta signaling. By increasing Smad3 acetylation in the cytoplasm, HDAC6 inhibition reduces Smad2/3 phosphorylation, nuclear translocation, and transcriptional activity. These findings provide in vivo evidence that Smad3 is a new target of HDAC6 and implicate HDAC6 as a potential therapeutic target in Duchenne muscular dystrophy.
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6
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Morotti M, Gaeta A, Limatola C, Catalano M, Di Castro MA, Grassi F. Early Developmental Changes of Muscle Acetylcholine Receptors Are Little Influenced by Dystrophin Absence in mdx Mouse. LIFE (BASEL, SWITZERLAND) 2022; 12:life12111861. [PMID: 36430996 PMCID: PMC9696329 DOI: 10.3390/life12111861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/09/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
Dystrophin is a cytoskeletal protein contributing to the organization of the neuromuscular junction. In Duchenne muscular dystrophy, due to dystrophin absence, the distribution of endplate acetylcholine receptors (AChRs) becomes disorganized. It is still debated whether this is due to the absence of dystrophin or to the repeated damage/regeneration cycles typical of dystrophic muscle. We addressed this controversy studying the endplate in the first 3 postnatal weeks, when muscle damage in dystrophic (mdx) mice is minimal. By synaptic and extra-synaptic patch-clamp recordings in acutely dissociated mdx and wt muscle fibers, we recorded unitary events due to openings of AChR-channels containing the γ and ε subunit. We also examined AChR distribution at the endplate by immunofluorescence assays. No differences between wt and mdx fibers were found in the γ/ε switch, nor in the AChR organization at the endplates up to 21 postnatal days. Conversely, we detected a delayed appearance and disappearance of patches with high channel opening frequency in mdx fibers. Our data emphasize that the innervation-dependent γ/ε switch and AChR organization in the endplate are not affected by the absence of dystrophin, while extra-synaptic AChR cluster formation and disassembly could be differentially regulated in mdx mice.
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Affiliation(s)
- Marta Morotti
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Alessandro Gaeta
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Cristina Limatola
- Laboratory Affiliated to Istituto Pasteur Italia, Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Istituto di Ricovero e Cura a Carattere Scientifico (IRCCS) Neuromed, 86077 Pozzilli, Italy
| | - Myriam Catalano
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Maria Amalia Di Castro
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
| | - Francesca Grassi
- Department of Physiology and Pharmacology, Sapienza University of Rome, 00185 Rome, Italy
- Correspondence:
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7
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Stefano MED, Ferretti V, Mozzetta C. Synaptic alterations as a neurodevelopmental trait of Duchenne muscular dystrophy. Neurobiol Dis 2022; 168:105718. [PMID: 35390481 DOI: 10.1016/j.nbd.2022.105718] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 01/14/2023] Open
Abstract
Dystrophinopaties, e.g., Duchenne muscular dystrophy (DMD), Becker muscular dystrophy and X-linked dilated cardiomyopathy are inherited neuromuscular diseases, characterized by progressive muscular degeneration, which however associate with a significant impact on general system physiology. The more severe is the pathology and its diversified manifestations, the heavier are its effects on organs, systems, and tissues other than muscles (skeletal, cardiac and smooth muscles). All dystrophinopaties are characterized by mutations in a single gene located on the X chromosome encoding dystrophin (Dp427) and its shorter isoforms, but DMD is the most devasting: muscular degenerations manifests within the first 4 years of life, progressively affecting motility and other muscular functions, and leads to a fatal outcome between the 20s and 40s. To date, after years of studies on both DMD patients and animal models of the disease, it has been clearly demonstrated that a significant percentage of DMD patients are also afflicted by cognitive, neurological, and autonomic disorders, of varying degree of severity. The anatomical correlates underlying neural functional damages are established during embryonic development and the early stages of postnatal life, when brain circuits, sensory and motor connections are still maturing. The impact of the absence of Dp427 on the development, differentiation, and consolidation of specific cerebral circuits (hippocampus, cerebellum, prefrontal cortex, amygdala) is significant, and amplified by the frequent lack of one or more of its lower molecular mass isoforms. The most relevant aspect, which characterizes DMD-associated neurological disorders, is based on morpho-functional alterations of selective synaptic connections within the affected brain areas. This pathological feature correlates neurological conditions of DMD to other severe neurological disorders, such as schizophrenia, epilepsy and autistic spectrum disorders, among others. This review discusses the organization and the role of the dystrophin-dystroglycan complex in muscles and neurons, focusing on the neurological aspect of DMD and on the most relevant morphological and functional synaptic alterations, in both central and autonomic nervous systems, described in the pathology and its animal models.
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Affiliation(s)
- Maria Egle De Stefano
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy.
| | - Valentina Ferretti
- Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy; Center for Research in Neurobiology Daniel Bovet, Sapienza University of Rome, 00185 Rome, Italy
| | - Chiara Mozzetta
- Institute of Molecular Biology and Pathology (IBPM), National Research Council (CNR) of Italy c/o Department of Biology and Biotechnology "Charles Darwin", Sapienza University of Rome, 00185 Rome, Italy
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8
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Evaluation of the dystrophin carboxy-terminal domain for micro-dystrophin gene therapy in cardiac and skeletal muscles in the DMD mdx rat model. Gene Ther 2022; 29:520-535. [PMID: 35105949 DOI: 10.1038/s41434-022-00317-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Revised: 12/09/2021] [Accepted: 01/13/2022] [Indexed: 01/02/2023]
Abstract
Duchenne muscular dystrophy (DMD) is a muscle wasting disorder caused by mutations in the gene encoding dystrophin. Gene therapy using micro-dystrophin (MD) transgenes and recombinant adeno-associated virus (rAAV) vectors hold great promise. To overcome the limited packaging capacity of rAAV vectors, most MD do not include dystrophin carboxy-terminal (CT) domain. Yet, the CT domain is known to recruit α1- and β1-syntrophins and α-dystrobrevin, a part of the dystrophin-associated protein complex (DAPC), which is a signaling and structural mediator of muscle cells. In this study, we explored the impact of inclusion of the dystrophin CT domain on ΔR4-23/ΔCT MD (MD1), in DMDmdx rats, which allows for relevant evaluations at muscular and cardiac levels. We showed by LC-MS/MS that MD1 expression is sufficient to restore the interactions at a physiological level of most DAPC partners in skeletal and cardiac muscles, and that inclusion of the CT domain increases the recruitment of some DAPC partners at supra-physiological levels. In parallel, we demonstrated that inclusion of the CT domain does not improve MD1 therapeutic efficacy on DMD muscle and cardiac pathologies. Our work highlights new evidences of the therapeutic potential of MD1 and strengthens the relevance of this candidate for gene therapy of DMD.
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9
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The Neuromuscular Junction: Roles in Aging and Neuromuscular Disease. Int J Mol Sci 2021; 22:ijms22158058. [PMID: 34360831 PMCID: PMC8347593 DOI: 10.3390/ijms22158058] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Revised: 07/20/2021] [Accepted: 07/22/2021] [Indexed: 02/07/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized synapse that bridges the motor neuron and the skeletal muscle fiber and is crucial for conversion of electrical impulses originating in the motor neuron to action potentials in the muscle fiber. The consideration of contributing factors to skeletal muscle injury, muscular dystrophy and sarcopenia cannot be restricted only to processes intrinsic to the muscle, as data show that these conditions incur denervation-like findings, such as fragmented NMJ morphology and corresponding functional changes in neuromuscular transmission. Primary defects in the NMJ also influence functional loss in motor neuron disease, congenital myasthenic syndromes and myasthenia gravis, resulting in skeletal muscle weakness and heightened fatigue. Such findings underscore the role that the NMJ plays in neuromuscular performance. Regardless of cause or effect, functional denervation is now an accepted consequence of sarcopenia and muscle disease. In this short review, we provide an overview of the pathologic etiology, symptoms, and therapeutic strategies related to the NMJ. In particular, we examine the role of the NMJ as a disease modifier and a potential therapeutic target in neuromuscular injury and disease.
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10
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Hui T, Jing H, Zhou T, Chen P, Liu Z, Dong X, Yan M, Ren D, Zou S, Wang S, Fei E, Hong D, Lai X. Increasing LRP4 diminishes neuromuscular deficits in a mouse model of Duchenne muscular dystrophy. Hum Mol Genet 2021; 30:1579-1590. [PMID: 33987657 PMCID: PMC8369839 DOI: 10.1093/hmg/ddab135] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 12/15/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease characterized by progressive wasting of skeletal muscles. The neuromuscular junction (NMJ) is a synapse between motor neurons and skeletal muscle fibers, critical for the control of muscle contraction. The NMJ decline is observed in DMD patients, but the mechanism is unclear. LRP4 serves as a receptor for agrin, a proteoglycan secreted by motor neurons to induce NMJ, and plays a critical role in NMJ formation and maintenance. Interestingly, we found that protein levels of LRP4 were reduced both in muscles of the DMD patients and DMD model mdx mice. We explored whether increasing LRP4 is beneficial for DMD and crossed muscle-specific LRP4 transgenic mice with mdx mice (mdx; HSA-LRP4). The LRP4 transgene increased muscle strength, together with improved neuromuscular transmission in mdx mice. Furthermore, we found the LRP4 expression mitigated NMJ fragments and denervation in mdx mice. Mechanically, we showed that overexpression of LRP4 increased the activity of MuSK and expression of dystrophin-associated glycoprotein complex proteins in the mdx mice. Overall, our findings suggest that increasing LRP4 improves both function and structure of NMJ in the mdx mice and Agrin signaling might serve as a new therapeutic strategy in DMD.
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Affiliation(s)
- Tiankun Hui
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Hongyang Jing
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Tian Zhou
- School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Peng Chen
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Ziyang Liu
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Xia Dong
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Min Yan
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Dongyan Ren
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Suqi Zou
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Shunqi Wang
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Erkang Fei
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
| | - Daojun Hong
- Department of Neurology, The First Affiliated Hospital of Nanchang University, Nanchang, Jiangxi, China
| | - Xinsheng Lai
- School of Life Science, Nanchang University, Nanchang, Jiangxi, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, Jiangxi, China
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11
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Dong X, Hui T, Chen J, Yu Z, Ren D, Zou S, Wang S, Fei E, Jiao H, Lai X. Metformin Increases Sarcolemma Integrity and Ameliorates Neuromuscular Deficits in a Murine Model of Duchenne Muscular Dystrophy. Front Physiol 2021; 12:642908. [PMID: 34012406 PMCID: PMC8126699 DOI: 10.3389/fphys.2021.642908] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Accepted: 04/12/2021] [Indexed: 12/12/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a genetic neuromuscular disease characterized by progressive muscle weakness and wasting. Stimulation of AMP-activated protein kinase (AMPK) has been demonstrated to increase muscle function and protect muscle against damage in dystrophic mice. Metformin is a widely used anti-hyperglycemic drug and has been shown to be an indirect activator of AMPK. Based on these findings, we sought to determine the effects of metformin on neuromuscular deficits in mdx murine model of DMD. In this study, we found metformin treatment increased muscle strength accompanied by elevated twitch and tetanic force of tibialis anterior (TA) muscle in mdx mice. Immunofluorescence and electron microscopy analysis of metformin-treated mdx muscles revealed an improvement in muscle fiber membrane integrity. Electrophysiological studies showed the amplitude of miniature endplate potentials (mEPP) was increased in treated mice, indicating metformin also improved neuromuscular transmission of the mdx mice. Analysis of mRNA and protein levels from muscles of treated mice showed an upregulation of AMPK phosphorylation and dystrophin-glycoprotein complex protein expression. In conclusion, metformin can indeed improve muscle function and diminish neuromuscular deficits in mdx mice, suggesting its potential use as a therapeutic drug in DMD patients.
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Affiliation(s)
- Xia Dong
- School of Basic Medical Sciences, Nanchang University, Nanchang, China.,Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China
| | - Tiankun Hui
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Jie Chen
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Zheng Yu
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China
| | - Dongyan Ren
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Suqi Zou
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Shunqi Wang
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Erkang Fei
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
| | - Huifeng Jiao
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Xinsheng Lai
- Laboratory of Synaptic Development and Plasticity, Institute of Life Science, Nanchang University, Nanchang, China.,School of Life Sciences, Nanchang University, Nanchang, China
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12
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Wang W, Xu C, Ma X, Zhang X, Xie P. Intensive Care Unit-Acquired Weakness: A Review of Recent Progress With a Look Toward the Future. Front Med (Lausanne) 2020; 7:559789. [PMID: 33330523 PMCID: PMC7719824 DOI: 10.3389/fmed.2020.559789] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Accepted: 09/11/2020] [Indexed: 12/16/2022] Open
Abstract
Intensive care unit-acquired weakness (ICU-AW), a common neuromuscular complication associated with patients in the ICU, is a type of skeletal muscle dysfunction that commonly occurs following sepsis, mobility restriction, hyperglycemia, and the use of glucocorticoids or neuromuscular blocking agents. ICU-AW can lead to delayed withdrawal of mechanical ventilation and extended hospitalization. Patients often have poor prognosis, limited mobility, and severely affected quality of life. Currently, its pathogenesis is uncertain, with unavailability of specific drugs or targeted therapies. ICU-AW has gained attention in recent years. This manuscript reviews the current research status of the epidemiology, pathogenesis, diagnosis, and treatment methods for ICU-AW and speculates the novel perspectives for future research.
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Affiliation(s)
- Wenkang Wang
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Chuanjie Xu
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Xinglong Ma
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
| | - Xiaoming Zhang
- Department of Molecular and Cellular Biology, Baylor College of Medicine Houston, Houston, TX, United States
| | - Peng Xie
- Department of Critical Care Medicine of the Third Affiliated Hospital (The First People's Hospital of Zunyi), Zunyi Medical University, Zunyi, China
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13
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Banks GB, Chamberlain JS, Odom GL. Microutrophin expression in dystrophic mice displays myofiber type differences in therapeutic effects. PLoS Genet 2020; 16:e1009179. [PMID: 33175853 PMCID: PMC7682874 DOI: 10.1371/journal.pgen.1009179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 11/23/2020] [Accepted: 10/06/2020] [Indexed: 12/28/2022] Open
Abstract
Gene therapy approaches for DMD using recombinant adeno-associated viral (rAAV) vectors to deliver miniaturized (or micro) dystrophin genes to striated muscles have shown significant progress. However, concerns remain about the potential for immune responses against dystrophin in some patients. Utrophin, a developmental paralogue of dystrophin, may provide a viable treatment option. Here we examine the functional capacity of an rAAV-mediated microutrophin (μUtrn) therapy in the mdx4cv mouse model of DMD. We found that rAAV-μUtrn led to improvement in dystrophic histopathology & mostly restored the architecture of the neuromuscular and myotendinous junctions. Physiological studies of tibialis anterior muscles indicated peak force maintenance, with partial improvement of specific force. A fundamental question for μUtrn therapeutics is not only can it replace critical functions of dystrophin, but whether full-length utrophin impacts the therapeutic efficacy of the smaller, highly expressed μUtrn. As such, we found that μUtrn significantly reduced the spacing of the costameric lattice relative to full-length utrophin. Further, immunostaining suggested the improvement in dystrophic pathophysiology was largely influenced by favored correction of fast 2b fibers. However, unlike μUtrn, μdystrophin (μDys) expression did not show this fiber type preference. Interestingly, μUtrn was better able to protect 2a and 2d fibers in mdx:utrn-/- mice than in mdx4cv mice where the endogenous full-length utrophin was most prevalent. Altogether, these data are consistent with the role of steric hindrance between full-length utrophin & μUtrn within the sarcolemma. Understanding the stoichiometry of this effect may be important for predicting clinical efficacy.
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MESH Headings
- Animals
- Dependovirus/genetics
- Disease Models, Animal
- Dystrophin/genetics
- Gene Transfer Techniques
- Genetic Therapy/methods
- Genetic Vectors/genetics
- HEK293 Cells
- Humans
- Mice
- Mice, Inbred mdx
- Microscopy, Electron
- Muscle Contraction
- Muscle Fibers, Skeletal/cytology
- Muscle Fibers, Skeletal/pathology
- Muscle Fibers, Skeletal/ultrastructure
- Muscle, Skeletal
- Muscular Dystrophy, Duchenne/genetics
- Muscular Dystrophy, Duchenne/pathology
- Muscular Dystrophy, Duchenne/therapy
- Neuromuscular Junction/pathology
- Neuromuscular Junction/ultrastructure
- Sarcolemma/pathology
- Sarcolemma/ultrastructure
- Utrophin/genetics
- Utrophin/therapeutic use
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Affiliation(s)
- Glen B. Banks
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington, United States of America
| | - Jeffrey S. Chamberlain
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington, United States of America
- Department of BioChemistry, University of Washington, Seattle, Washington, United States of America
| | - Guy L. Odom
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
- Department of Medicine, University of Washington, Seattle, Washington, United States of America
- Wellstone Muscular Dystrophy Specialized Research Center, University of Washington, Seattle, Washington, United States of America
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14
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Cossins J, Webster R, Maxwell S, Rodríguez Cruz PM, Knight R, Llewelyn JG, Shin JY, Palace J, Beeson D. Congenital myasthenic syndrome due to a TOR1AIP1 mutation: a new disease pathway for impaired synaptic transmission. Brain Commun 2020; 2:fcaa174. [PMID: 33215087 PMCID: PMC7660151 DOI: 10.1093/braincomms/fcaa174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 07/24/2020] [Accepted: 08/12/2020] [Indexed: 02/06/2023] Open
Abstract
Congenital myasthenic syndromes are inherited disorders characterized by fatiguable muscle weakness resulting from impaired signal transmission at the neuromuscular junction. Causative mutations have been identified in genes that can affect the synaptic function or structure. We identified a homozygous frameshift deletion c.127delC, p. Pro43fs in TOR1AIP1 in two siblings with limb-girdle weakness and impaired transmission at the neuromuscular synapse. TOR1AIP1 encodes the inner nuclear membrane protein lamin-associated protein 1. On muscle biopsy from the index case, lamin-associated protein 1 was absent from myonuclei. A mouse model with lamin-associated protein 1 conditionally knocked out in striated muscle was used to analyse the role of lamin-associated protein 1 in synaptic dysfunction. Model mice develop fatiguable muscle weakness as demonstrated by using an inverted screen hang test. Electromyography on the mice revealed a decrement on repetitive nerve stimulation. Ex vivo analysis of hemi-diaphragm preparations showed both miniature and evoked end-plate potential half-widths were prolonged which was associated with upregulation of the foetal acetylcholine receptor γ subunit. Neuromuscular junctions on extensor digitorum longus muscles were enlarged and fragmented, and the number of subsynaptic nuclei was significantly increased. Following these findings, electromyography was performed on cases of other nuclear envelopathies caused by mutations in LaminA/C or emerin, but decrement on repetitive nerve stimulation or other indications of defective neuromuscular transmission were not seen. Thus, this report highlights the first nuclear membrane protein in which defective function can lead to impaired synaptic transmission.
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Affiliation(s)
- Judith Cossins
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Richard Webster
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Susan Maxwell
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Pedro M Rodríguez Cruz
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
| | - Ravi Knight
- Department of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - John Gareth Llewelyn
- Neurology Department, University Hospital of Wales, Heath Park, Cardiff CF14 4XW, UK
| | - Ji-Yeon Shin
- Department of Medicine, Columbia University Medical Centre, New York, NY 10032, USA
| | - Jacqueline Palace
- Department of Clinical Neurology, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford OX3 9DS, UK
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15
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Ng SY, Ljubicic V. Recent insights into neuromuscular junction biology in Duchenne muscular dystrophy: Impacts, challenges, and opportunities. EBioMedicine 2020; 61:103032. [PMID: 33039707 PMCID: PMC7648118 DOI: 10.1016/j.ebiom.2020.103032] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/28/2020] [Accepted: 09/11/2020] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most common and relentless form of muscular dystrophy. The pleiotropic effects of dystrophin deficiency include remarkable impacts on neuromuscular junction (NMJ) structure and function. Some of these alterations contribute to the severe muscle wasting and weakness that distinguish DMD, while others attempt to compensate for them. Experimental approaches that correct NMJ biology in pre-clinical models of DMD attenuate disease progression and improve functional outcomes, which suggests that targeting the NMJ may be an effective therapeutic strategy for DMD patients. The objectives of this review are to 1) survey the distinctions in NMJ structure, function, and gene expression in the dystrophic context as compared to the healthy condition, and 2) summarize the efforts, opportunities and challenges to correct NMJ biology in DMD. This information will expand our basic understanding of neuromuscular biology and may be useful for designing novel NMJ-targeted drug or behavioural strategies to mitigate the dystrophic pathology and other disorders of the neuromuscular system.
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Affiliation(s)
- Sean Y Ng
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada.
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16
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Lovering RM, Iyer SR, Edwards B, Davies KE. Alterations of neuromuscular junctions in Duchenne muscular dystrophy. Neurosci Lett 2020; 737:135304. [PMID: 32818587 DOI: 10.1016/j.neulet.2020.135304] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 08/09/2020] [Accepted: 08/11/2020] [Indexed: 12/18/2022]
Abstract
The focus of this review is on Duchenne muscular dystrophy (DMD), which is caused by the absence of the protein dystrophin and is characterized as a neuromuscular disease in which muscle weakness, increased susceptibility to muscle injury, and inadequate repair appear to underlie the pathology. Considerable attention has been dedicated to studying muscle fiber damage, but data show that both human patients and animal models for DMD present with fragmented neuromuscular junction (NMJ) morphology. In addition to pre- and post-synaptic abnormalities, studies indicate increased susceptibility of the NMJ to contraction-induced injury, with corresponding functional changes in neuromuscular transmission and nerve-evoked electromyographic activity. Such findings suggest that alterations in the NMJ of dystrophic muscle may play a role in muscle weakness via impairment of neuromuscular transmission. Further work is needed to fully understand the role of the NMJ in the weakness, susceptibility to injury, and progressive wasting associated with DMD.
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Affiliation(s)
- Richard M Lovering
- Departments of Orthopaedics and Physiology, University of Maryland School of Medicine, Baltimore, MD, USA; University of Maryland School of Medicine, Baltimore, MD, USA.
| | - Shama R Iyer
- Departments of Orthopaedics and Physiology, University of Maryland School of Medicine, Baltimore, MD, USA
| | - Benjamin Edwards
- MDUK Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Kay E Davies
- MDUK Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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17
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Senoo N, Miyoshi N, Kobayashi E, Morita A, Tanihata J, Takeda S, Miura S. Glycerophospholipid profile alterations are associated with murine muscle-wasting phenotype. Muscle Nerve 2020; 62:413-418. [PMID: 32496590 DOI: 10.1002/mus.26993] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/21/2020] [Accepted: 05/30/2020] [Indexed: 11/08/2022]
Abstract
INTRODUCTION Phospholipids are essential components of cellular membranes and are closely associated with cellular functions, but relationships involving skeletal muscle phospholipid profiles and their physiological phenotypes have remained unclear. METHODS We carried out comprehensive phospholipid analyses using liquid chromatography-tandem mass spectrometry to determine the phospholipid profiles of skeletal muscles derived from muscle-wasting mouse models, including denervated and Duchenne muscular dystrophy mouse models (mdx) as well as rescued mdx mice expressing truncated dystrophin. RESULTS Consistent phosphatidylcholine and phosphatidylethanolamine alterations in skeletal muscles isolated from denervated and mdx mice were observed. Notably, the levels of these phospholipids binding polyunsaturated fatty acids were reduced in denervated and mdx muscles. Moreover, rescuing the mdx pathology by expressing truncated dystrophin led to the restoration of phospholipid profiles. DISCUSSION Our findings support the hypothesis that phospholipid profiles of the skeletal muscle may be associated with skeletal muscle function.
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Affiliation(s)
- Nanami Senoo
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan.,Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Noriyuki Miyoshi
- Laboratory of Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Eri Kobayashi
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Akihito Morita
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Jun Tanihata
- Department of Molecular Therapy, National Institute of Neuroscience, National Center for Neurology and Psychiatry, Kodaira, Tokyo, Japan.,Department of Cell Physiology, Jikei University School of Medicine, Tokyo, Japan
| | - Shin'ichi Takeda
- Department of Molecular Therapy, National Institute of Neuroscience, National Center for Neurology and Psychiatry, Kodaira, Tokyo, Japan
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
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18
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Shahnoor N, Siebers EM, Brown KJ, Lawlor MW. Pathological Issues in Dystrophinopathy in the Age of Genetic Therapies. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2018; 14:105-126. [PMID: 30148687 DOI: 10.1146/annurev-pathmechdis-012418-012945] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Dystrophinopathy is a class of genetic skeletal muscle disease characterized by myofiber degeneration and regeneration due to insufficient levels or functioning of dystrophin. Pathological evaluation for dystrophinopathy includes the identification of dystrophic skeletal muscle pathology and the immunohistochemical evaluation of dystrophin epitopes, but biopsies have become rare in recent years. However, the evaluation of dystrophin expression in the research setting has become critically important due to recent advances in genetic therapies, including exon skipping and gene therapy. Given the number of these therapies under evaluation in patients, it is likely that the traditional methods of evaluating dystrophinopathy will need to evolve in the near future. This review discusses current muscle biopsy diagnostic practices in dystrophinopathy and further focuses on how these practices have evolved in the context of therapeutic interventions for dystrophinopathy.
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Affiliation(s)
- Nazima Shahnoor
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
| | - Emily M Siebers
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
| | - Kristy J Brown
- Solid Biosciences, Inc., Cambridge, Massachusetts 02139, USA;
| | - Michael W Lawlor
- Department of Pathology and Laboratory Medicine, and Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA; , ,
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19
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Pratt SJP, Iyer SR, Shah SB, Lovering RM. Imaging Analysis of the Neuromuscular Junction in Dystrophic Muscle. Methods Mol Biol 2018; 1687:57-72. [PMID: 29067656 DOI: 10.1007/978-1-4939-7374-3_5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Duchenne muscular dystrophy (DMD), caused by the absence of the protein dystrophin, is characterized as a neuromuscular disease in which muscle weakness, increased susceptibility to muscle injury, and inadequate repair appear to underlie the pathology. Considerable attention has been dedicated to studying muscle fiber damage, but there is little information to determine if damage from contraction-induced injury also occurs at or near the nerve terminal axon. Interestingly, both human patients and the mouse model for DMD (the mdx mouse) present fragmented neuromuscular junction (NMJ) morphology. Studies of mdx mice have revealed presynaptic and postsynaptic abnormalities, nerve terminal discontinuity, as well as increased susceptibility of the NMJ to contraction-induced injury with corresponding functional changes in neuromuscular transmission and nerve-evoked electromyography. Focusing on the NMJ as a contributor to functional deficits in the muscle represents a paradigm shift from the more prevalent myocentric perspectives. Further studies are needed to determine the extent to which the nerve-muscle interaction is disrupted in DMD and the role of the NMJ in the dystrophic progression. This chapter lists the tools needed for nerve terminal and NMJ structural analysis using fluorescence imaging, and provides a step-by-step outline for how to stain, image, and analyze the NMJ in skeletal muscle, with specific attention to mdx muscle.
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Affiliation(s)
- Stephen J P Pratt
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore School of Medicine, Baltimore, MD, USA
| | - Shama R Iyer
- Department of Orthopaedics, University of Maryland, Baltimore School of Medicine, 100 Penn St., AHB, Room 540, Baltimore, MD, 21201, USA
| | - Sameer B Shah
- Departments of Orthopaedic Surgery and Bioengineering, University of California San Diego, La Jolla, CA, 92093, USA
- Research Division, Veterans Administration San Diego Healthcare System, San Diego, CA, 92121, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland, Baltimore School of Medicine, 100 Penn St., AHB, Room 540, Baltimore, MD, 21201, USA.
- Department of Physiology, University of Maryland, Baltimore School of Medicine, Baltimore, MD, USA.
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20
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Kamdar F, Garry DJ. Dystrophin-Deficient Cardiomyopathy. J Am Coll Cardiol 2017; 67:2533-46. [PMID: 27230049 DOI: 10.1016/j.jacc.2016.02.081] [Citation(s) in RCA: 227] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Revised: 02/16/2016] [Accepted: 02/23/2016] [Indexed: 12/25/2022]
Abstract
Dystrophinopathies are a group of distinct neuromuscular diseases that result from mutations in the structural cytoskeletal Dystrophin gene. Dystrophinopathies include Duchenne muscular dystrophy (DMD) and Becker muscular dystrophy (BMD), X-linked dilated cardiomyopathy, as well as DMD and BMD female carriers. The primary presenting symptom in most dystrophinopathies is skeletal muscle weakness. However, cardiac muscle is also a subtype of striated muscle and is similarly affected in many of the muscular dystrophies. Cardiomyopathies associated with dystrophinopathies are an increasingly recognized manifestation of these neuromuscular disorders and contribute significantly to their morbidity and mortality. Recent studies suggest that these patient populations would benefit from cardiovascular therapies, annual cardiovascular imaging studies, and close follow-up with cardiovascular specialists. Moreover, patients with DMD and BMD who develop end-stage heart failure may benefit from the use of advanced therapies. This review focuses on the pathophysiology, cardiac involvement, and treatment of cardiomyopathy in the dystrophic patient.
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Affiliation(s)
- Forum Kamdar
- Cardiovascular Division, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota
| | - Daniel J Garry
- Cardiovascular Division, Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota.
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21
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Nance ME, Hakim CH, Yang NN, Duan D. Nanotherapy for Duchenne muscular dystrophy. WILEY INTERDISCIPLINARY REVIEWS-NANOMEDICINE AND NANOBIOTECHNOLOGY 2017; 10. [PMID: 28398005 DOI: 10.1002/wnan.1472] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 02/09/2017] [Accepted: 03/11/2017] [Indexed: 12/14/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a lethal X-linked childhood muscle wasting disease caused by mutations in the dystrophin gene. Nanobiotechnology-based therapies (such as synthetic nanoparticles and naturally existing viral and nonviral nanoparticles) hold great promise to replace and repair the mutated dystrophin gene and significantly change the disease course. While a majority of DMD nanotherapies are still in early preclinical development, several [such as adeno-associated virus (AAV)-mediated systemic micro-dystrophin gene therapy] are advancing for phase I clinical trials. Recent regulatory approval of Ataluren (a nonsense mutation read-through chemical) in Europe and Exondys51 (an exon-skipping antisense oligonucleotide drug) in the United States shall offer critical insight in how to move DMD nanotherapy to human patients. Progress in novel, optimized nano-delivery systems may further improve emerging molecular therapeutic modalities for DMD. Despite these progresses, DMD nanotherapy faces a number of unique challenges. Specifically, the dystrophin gene is one of the largest genes in the genome while nanoparticles have an inherent size limitation per definition. Furthermore, muscle is the largest tissue in the body and accounts for 40% of the body mass. How to achieve efficient bodywide muscle targeting in human patients with nanomedication remains a significant translational hurdle. New creative approaches in the design of the miniature micro-dystrophin gene, engineering of muscle-specific synthetic AAV capsids, and novel nanoparticle-mediated exon-skipping are likely to result in major breakthroughs in DMD therapy. WIREs Nanomed Nanobiotechnol 2018, 10:e1472. doi: 10.1002/wnan.1472 This article is categorized under: Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.
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Affiliation(s)
- Michael E Nance
- Department of Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO, USA
| | - Chady H Hakim
- Department of Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO, USA.,National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - N Nora Yang
- National Center for Advancing Translational Sciences, NIH, Rockville, MD, USA
| | - Dongsheng Duan
- Department of Microbiology and Immunology, University of Missouri School of Medicine, Columbia, MO, USA.,Department of Neurology, University of Missouri, Columbia, MO, USA.,Department of Bioengineering, University of Missouri, Columbia, MO, USA.,Department of Biomedical Sciences, University of Missouri, Columbia, MO, USA
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22
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Capogrosso RF, Mantuano P, Cozzoli A, Sanarica F, Massari AM, Conte E, Fonzino A, Giustino A, Rolland JF, Quaranta A, De Bellis M, Camerino GM, Grange RW, De Luca A. Contractile efficiency of dystrophic mdx mouse muscle: in vivo and ex vivo assessment of adaptation to exercise of functional end points. J Appl Physiol (1985) 2017; 122:828-843. [PMID: 28057817 DOI: 10.1152/japplphysiol.00776.2015] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/03/2017] [Accepted: 01/03/2017] [Indexed: 11/22/2022] Open
Abstract
Progressive weakness is a typical feature of Duchenne muscular dystrophy (DMD) patients and is exacerbated in the benign mdx mouse model by in vivo treadmill exercise. We hypothesized a different threshold for functional adaptation of mdx muscles in response to the duration of the exercise protocol. In vivo weakness was confirmed by grip strength after 4, 8, and 12 wk of exercise in mdx mice. Torque measurements revealed that exercise-related weakness in mdx mice correlated with the duration of the protocol, while wild-type (WT) mice were stronger. Twitch and tetanic forces of isolated diaphragm and extensor digitorum longus (EDL) muscles were lower in mdx compared with WT mice. In mdx, both muscle types exhibited greater weakness after a single exercise bout, but only in EDL after a long exercise protocol. As opposite to WT muscles, mdx EDL ones did not show any exercise-induced adaptations against eccentric contraction force drop. qRT-PCR analysis confirmed the maladaptation of genes involved in metabolic and structural remodeling, while damage-related genes remained significantly upregulated and angiogenesis impaired. Phosphorylated AMP kinase level increased only in exercised WT muscle. The severe histopathology and the high levels of muscular TGF-β1 and of plasma matrix metalloproteinase-9 confirmed the persistence of muscle damage in mdx mice. Therefore, dystrophic muscles showed a partial degree of functional adaptation to chronic exercise, although not sufficient to overcome weakness nor signs of damage. The improved understanding of the complex mechanisms underlying maladaptation of dystrophic muscle paves the way to a better managment of DMD patients.NEW & NOTEWORTHY We focused on the adaptation/maladaptation of dystrophic mdx mouse muscles to a standard protocol of exercise to provide guidance in the development of more effective drug and physical therapies in Duchenne muscular dystrophy. The mdx muscles showed a modest functional adaptation to chronic exercise, but it was not sufficient to overcome the progressive in vivo weakness, nor to counter signs of muscle damage. Therefore, a complex involvement of multiple systems underlies the maladaptive response of dystrophic muscle.
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Affiliation(s)
- Roberta Francesca Capogrosso
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy.,Department of Chemical, Toxicological and Pharmacological Drug Studies, Catholic University "Our Lady of Good Counsel," Tirana, Albany
| | - Paola Mantuano
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Anna Cozzoli
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Francesca Sanarica
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Ada Maria Massari
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Elena Conte
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Adriano Fonzino
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Arcangela Giustino
- Department of Biomedical Sciences and Human Oncology, School of Medicine, University of Bari "Aldo Moro," Bari, Italy
| | - Jean-Francois Rolland
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Angelo Quaranta
- Department of Veterinary Medicine, University of Bari "Aldo Moro," Valenzano (BA), Italy
| | - Michela De Bellis
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Giulia Maria Camerino
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy
| | - Robert W Grange
- Department of Human Nutrition, Foods, and Exercise, Virginia Tech University, Blacksburg, Virginia; and
| | - Annamaria De Luca
- Section of Pharmacology, Department of Pharmacy and Drug Sciences, University of Bari "Aldo Moro," Bari, Italy;
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23
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Axonal degeneration, distal collateral branching and neuromuscular junction architecture alterations occur prior to symptom onset in the SOD1G93A mouse model of amyotrophic lateral sclerosis. J Chem Neuroanat 2016; 76:35-47. [DOI: 10.1016/j.jchemneu.2016.03.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2015] [Revised: 01/29/2016] [Accepted: 03/19/2016] [Indexed: 12/11/2022]
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Poort JE, Rheuben MB, Breedlove SM, Jordan CL. Neuromuscular junctions are pathological but not denervated in two mouse models of spinal bulbar muscular atrophy. Hum Mol Genet 2016; 25:3768-3783. [PMID: 27493028 DOI: 10.1093/hmg/ddw222] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 06/15/2016] [Accepted: 07/04/2016] [Indexed: 12/21/2022] Open
Abstract
Spinal bulbar muscular atrophy (SBMA) is a progressive, late onset neuromuscular disease causing motor dysfunction in men. While the morphology of the neuromuscular junction (NMJ) is typically affected by neuromuscular disease, whether NMJs in SBMA are similarly affected by disease is not known. Such information will shed light on whether defective NMJs might contribute to the loss of motor function and represent a potential therapeutic target for treating symptoms of SBMA. To address this gap in information, the morphology of NMJs was examined in two mouse models of SBMA, a myogenic model that overexpresses wildtype androgen receptor (AR) exclusively in muscle fibres and a knockin (KI) model expressing a humanized mutant AR gene. The tripartite motor synapse consisting of motor nerve terminal, terminal Schwann cells (tSCs) and postsynaptic specialization were visualized and analysed using confocal microscopy. Counter to expectation, we found no evidence of denervation in either model, but junctions in both models show pathological fragmentation and an abnormal synaptophysin distribution consistent with functionally weak synapses. Neurofilament accumulations were observed only in the myogenic model, even though axonal transport dysfunction is characteristic of both models. The ultrastructure of NMJs revealed additional pathology, including deficits in docked vesicles presynaptically, wider synaptic clefts, and simpler secondary folds postsynaptically. The observed pathology of NMJs in diseased SBMA mice is likely the morphological correlates of defects in synaptic function which may underlie motor impairments associated with SBMA.
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Affiliation(s)
| | - Mary B Rheuben
- Neuroscience Program, Michigan State University, MI, USA
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25
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Matchkov VV, Krivoi II. Specialized Functional Diversity and Interactions of the Na,K-ATPase. Front Physiol 2016; 7:179. [PMID: 27252653 PMCID: PMC4879863 DOI: 10.3389/fphys.2016.00179] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/04/2016] [Indexed: 12/22/2022] Open
Abstract
Na,K-ATPase is a protein ubiquitously expressed in the plasma membrane of all animal cells and vitally essential for their functions. A specialized functional diversity of the Na,K-ATPase isozymes is provided by molecular heterogeneity, distinct subcellular localizations, and functional interactions with molecular environment. Studies over the last decades clearly demonstrated complex and isoform-specific reciprocal functional interactions between the Na,K-ATPase and neighboring proteins and lipids. These interactions are enabled by a spatially restricted ion homeostasis, direct protein-protein/lipid interactions, and protein kinase signaling pathways. In addition to its "classical" function in ion translocation, the Na,K-ATPase is now considered as one of the most important signaling molecules in neuronal, epithelial, skeletal, cardiac and vascular tissues. Accordingly, the Na,K-ATPase forms specialized sub-cellular multimolecular microdomains which act as receptors to circulating endogenous cardiotonic steroids (CTS) triggering a number of signaling pathways. Changes in these endogenous cardiotonic steroid levels and initiated signaling responses have significant adaptive values for tissues and whole organisms under numerous physiological and pathophysiological conditions. This review discusses recent progress in the studies of functional interactions between the Na,K-ATPase and molecular microenvironment, the Na,K-ATPase-dependent signaling pathways and their significance for diversity of cell function.
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Affiliation(s)
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University St. Petersburg, Russia
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van der Pijl EM, van Putten M, Niks EH, Verschuuren JJGM, Aartsma-Rus A, Plomp JJ. Characterization of neuromuscular synapse function abnormalities in multiple Duchenne muscular dystrophy mouse models. Eur J Neurosci 2016; 43:1623-35. [PMID: 27037492 DOI: 10.1111/ejn.13249] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 03/22/2016] [Accepted: 03/23/2016] [Indexed: 11/30/2022]
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked myopathy caused by dystrophin deficiency. Dystrophin is present intracellularly at the sarcolemma, connecting actin to the dystrophin-associated glycoprotein complex. Interestingly, it is enriched postsynaptically at the neuromuscular junction (NMJ), but its synaptic function is largely unknown. Utrophin, a dystrophin homologue, is also concentrated at the NMJ, and upregulated in DMD. It is possible that the absence of dystrophin at NMJs in DMD causes neuromuscular transmission defects that aggravate muscle weakness. We studied NMJ function in mdx mice (lacking dystrophin) and wild type mice. In addition, mdx/utrn(+/-) and mdx/utrn(-/-) mice (lacking utrophin) were used to investigate influences of utrophin levels. The three Duchenne mouse models showed muscle weakness when comparatively tested in vivo, with mdx/utrn(-/-) mice being weakest. Ex vivo muscle contraction and electrophysiological studies showed a reduced safety factor of neuromuscular transmission in all models. NMJs had ~ 40% smaller miniature endplate potential amplitudes compared with wild type, indicating postsynaptic sensitivity loss for the neurotransmitter acetylcholine. However, nerve stimulation-evoked endplate potential amplitudes were unchanged. Consequently, quantal content (i.e. the number of acetylcholine quanta released per nerve impulse) was considerably increased. Such a homeostatic compensatory increase in neurotransmitter release is also found at NMJs in myasthenia gravis, where autoantibodies reduce acetylcholine receptors. However, high-rate nerve stimulation induced exaggerated endplate potential rundown. Study of NMJ morphology showed that fragmentation of acetylcholine receptor clusters occurred in all models, being most severe in mdx/utrn(-/-) mice. Overall, we showed mild 'myasthenia-like' neuromuscular synaptic dysfunction in several Duchenne mouse models, which possibly affects muscle weakness and degeneration.
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Affiliation(s)
- Elizabeth M van der Pijl
- Department of Neurology, Leiden University Medical Centre, Research Building S5-P, P.O. Box 9600 2300 RC, Leiden, The Netherlands
| | - Maaike van Putten
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Erik H Niks
- Department of Neurology, Leiden University Medical Centre, Research Building S5-P, P.O. Box 9600 2300 RC, Leiden, The Netherlands
| | - Jan J G M Verschuuren
- Department of Neurology, Leiden University Medical Centre, Research Building S5-P, P.O. Box 9600 2300 RC, Leiden, The Netherlands
| | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Centre, Leiden, The Netherlands
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Centre, Research Building S5-P, P.O. Box 9600 2300 RC, Leiden, The Netherlands
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27
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Roberts TC, Johansson HJ, McClorey G, Godfrey C, Blomberg KEM, Coursindel T, Gait MJ, Smith CIE, Lehtiö J, El Andaloussi S, Wood MJA. Multi-level omics analysis in a murine model of dystrophin loss and therapeutic restoration. Hum Mol Genet 2015; 24:6756-68. [PMID: 26385637 PMCID: PMC4634378 DOI: 10.1093/hmg/ddv381] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Accepted: 09/11/2015] [Indexed: 01/16/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a classical monogenic disorder, a model disease for genomic studies and a priority candidate for regenerative medicine and gene therapy. Although the genetic cause of DMD is well known, the molecular pathogenesis of disease and the response to therapy are incompletely understood. Here, we describe analyses of protein, mRNA and microRNA expression in the tibialis anterior of the mdx mouse model of DMD. Notably, 3272 proteins were quantifiable and 525 identified as differentially expressed in mdx muscle (P < 0.01). Therapeutic restoration of dystrophin by exon skipping induced widespread shifts in protein and mRNA expression towards wild-type expression levels, whereas the miRNome was largely unaffected. Comparison analyses between datasets showed that protein and mRNA ratios were only weakly correlated (r = 0.405), and identified a multitude of differentially affected cellular pathways, upstream regulators and predicted miRNA-target interactions. This study provides fundamental new insights into gene expression and regulation in dystrophic muscle.
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Affiliation(s)
- Thomas C Roberts
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK, Sanford Burnham Prebys Medical Discovery Institute, Development, Aging and Regeneration Program, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Henrik J Johansson
- Department of Oncology/Pathology, Cancer Proteomics Mass Spectrometry, SciLifeLab Stockholm, Karolinska Institutet, Stockholm SE-171 21, Sweden
| | - Graham McClorey
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - Caroline Godfrey
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK
| | - K Emelie M Blomberg
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge SE-141 86, Sweden and
| | - Thibault Coursindel
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - Michael J Gait
- Laboratory of Molecular Biology, Medical Research Council, Francis Crick Avenue, Cambridge CB2 0QH, UK
| | - C I Edvard Smith
- Department of Laboratory Medicine, Karolinska Institutet, Huddinge SE-141 86, Sweden and
| | - Janne Lehtiö
- Department of Oncology/Pathology, Cancer Proteomics Mass Spectrometry, SciLifeLab Stockholm, Karolinska Institutet, Stockholm SE-171 21, Sweden
| | - Samir El Andaloussi
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK, Department of Laboratory Medicine, Karolinska Institutet, Huddinge SE-141 86, Sweden and
| | - Matthew J A Wood
- Department of Physiology, Anatomy and Genetics, University of Oxford, South Parks Road, Oxford OX1 3QX, UK,
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Pratt SJP, Valencia AP, Le GK, Shah SB, Lovering RM. Pre- and postsynaptic changes in the neuromuscular junction in dystrophic mice. Front Physiol 2015; 6:252. [PMID: 26441672 PMCID: PMC4563167 DOI: 10.3389/fphys.2015.00252] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 08/28/2015] [Indexed: 01/05/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a devastating neuromuscular disease in which weakness, increased susceptibility to muscle injury, and inadequate repair appear to underlie the pathology. While most attention has focused within the muscle fiber, we recently demonstrated in mdx mice (murine model for DMD) significant morphologic alterations at the motor endplate of the neuromuscular junction (NMJ) and corresponding NMJ transmission failure after injury. Here we extend these initial observations at the motor endplate to gain insight into the pre- vs. postsynaptic morphology, as well as the subsynaptic nuclei in healthy (WT) vs. mdx mice. We quantified the discontinuity and branching of the terminal nerve in adult mice. We report mdx- and age-dependent changes for discontinuity and an increase in branching when compared to WT. To examine mdx- and age-dependent changes in the relative localization of pre- and postsynaptic structures, we calculated NMJ occupancy, defined as the ratio of the footprint occupied by presynaptic vesicles vs. that of the underlying motor endplate. The normally congruent coupling between presynaptic and postsynaptic morphology was altered in mdx mice, independent of age. Finally we found an almost two-fold increase in the number of nuclei and an increase in density (nuclei/area) underlying the NMJ. These outcomes suggest substantial remodeling of the NMJ during dystrophic progression. This remodeling reflects plasticity in both pre- and postsynaptic contributors to NMJ structure, and thus perhaps also NM transmission and muscle function.
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Affiliation(s)
- Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Ana P Valencia
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA ; Department of Kinesiology, University of Maryland School of Public Health College Park, MD, USA
| | - Gloribel K Le
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
| | - Sameer B Shah
- Departments of Orthopaedic Surgery and Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine Baltimore, MD, USA
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Muscle-derived extracellular signal-regulated kinases 1 and 2 are required for the maintenance of adult myofibers and their neuromuscular junctions. Mol Cell Biol 2015; 35:1238-53. [PMID: 25605336 DOI: 10.1128/mcb.01071-14] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The Ras-extracellular signal-regulated kinase 1 and 2 (ERK1/2) pathway appears to be important for the development, maintenance, aging, and pathology of mammalian skeletal muscle. Yet no gene targeting of Erk1/2 in muscle fibers in vivo has been reported to date. We combined a germ line Erk1 mutation with Cre-loxP Erk2 inactivation in skeletal muscle to produce, for the first time, mice lacking ERK1/2 selectively in skeletal myofibers. Animals lacking muscle ERK1/2 displayed stunted postnatal growth, muscle weakness, and a shorter life span. Their muscles examined in this study, sternomastoid and tibialis anterior, displayed fragmented neuromuscular synapses and a mixture of modest fiber atrophy and loss but failed to show major changes in fiber type composition or absence of cell surface dystrophin. Whereas the lack of only ERK1 had no effects on the phenotypes studied, the lack of myofiber ERK2 explained synaptic fragmentation in the sternomastoid but not the tibialis anterior and a decrease in the expression of the acetylcholine receptor (AChR) epsilon subunit gene mRNA in both muscles. A reduction in AChR protein was documented in line with the above mRNA results. Evidence of partial denervation was found in the sternomastoid but not the tibialis anterior. Thus, myofiber ERK1/2 are differentially required for the maintenance of myofibers and neuromuscular synapses in adult mice.
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30
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Vianello S, Bouyon S, Benoit E, Sebrié C, Boerio D, Herbin M, Roulot M, Fromes Y, de la Porte S. Arginine butyrate per os protects mdx mice against cardiomyopathy, kyphosis and changes in axonal excitability. Neurobiol Dis 2014; 71:325-33. [PMID: 25167832 DOI: 10.1016/j.nbd.2014.08.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 08/08/2014] [Accepted: 08/16/2014] [Indexed: 11/30/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a progressive neuromuscular disease caused by lack of dystrophin, a sub-sarcolemmal protein, which leads to dramatic muscle deterioration. We studied in mdx mice, the effects of oral administration of arginine butyrate (AB), a compound currently used for the treatment of sickle cell anemia in children, on cardiomyopathy, vertebral column deformation and electromyographic abnormalities. Monthly follow-up by echocardiography from the 8th month to the 14th month showed that AB treatment protected the mdx mice against drastic reduction (20-23%) of ejection fraction and fractional shortening, and also against the ≈20% ventricular dilatation and 25% cardiac hypertrophy observed in saline-treated mdx mice. The phenotypic improvement was corroborated by the decrease in serum CK level and by better fatigue resistance. Moreover, AB treatment protected against the progressive spinal deformity observed in mdx mice, another similarity with DMD patients. The value of the kyphosis index in AB-treated mice reached 94% of the value in C57BL/10 mice. Finally, axonal excitability parameters such as the membrane resting potential, the threshold and amplitude of the action potential, the absolute and relative refractory periods and the supernormal and subnormal periods, recorded from caudal and plantar muscles in response to excitability tests, that were modified in saline-treated mdx mice were not significantly changed, compared with wild-type animals, in AB-treated mdx mice. All of these results suggest that AB could be a potential treatment for DMD patients.
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Affiliation(s)
- Sara Vianello
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Neurobiologie & Développement, UPR 3294, Gif sur Yvette, F-91198, France.
| | - Sophie Bouyon
- UPMC, Université Paris 6, UMR 974, Institut de Myologie, F-75013 Paris, France.
| | - Evelyne Benoit
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Neurobiologie & Développement, UPR 3294, Gif sur Yvette, F-91198, France.
| | | | - Delphine Boerio
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Neurobiologie & Développement, UPR 3294, Gif sur Yvette, F-91198, France.
| | - Marc Herbin
- CNRS, Muséum National d'Histoire Naturelle, CNRS, UMR7179, Pavillon d'anatomie comparée, BP 55, 52 Rue Cuvier, 75231 Paris Cedex 05, France.
| | - Morgane Roulot
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Neurobiologie & Développement, UPR 3294, Gif sur Yvette, F-91198, France.
| | - Yves Fromes
- UPMC, Université Paris 6, UMR 974, Institut de Myologie, F-75013 Paris, France; ONIRIS, Centre de Boisbonne, Nantes F-44307, France.
| | - Sabine de la Porte
- CNRS, Institut de Neurobiologie Alfred Fessard, FRC2118, Neurobiologie & Développement, UPR 3294, Gif sur Yvette, F-91198, France.
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31
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Rocco AB, Levalley JC, Eldridge JA, Marsh SA, Rodgers BD. A novel protocol for assessing exercise performance and dystropathophysiology in the mdx mouse. Muscle Nerve 2014; 50:541-8. [PMID: 24449511 DOI: 10.1002/mus.24184] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Revised: 01/06/2014] [Accepted: 01/15/2014] [Indexed: 11/11/2022]
Abstract
INTRODUCTION Dystrophinopathy in the young mdx mouse model of Duchenne muscular dystrophy is comparatively mild, requires induction, and is rarely assessed with tests of systemic muscle function in whole animals. METHODS A modified TREAT-NMD induction protocol was used to evaluate respiratory and exercise performance, starting and ending with maximum oxygen consumption (VO2max ) tests. RESULTS The initial and/or final VO2max , time to exhaustion, speed at exhaustion, and total expended calories were significantly lower in mdx mice. Episodic VO2 and VCO2 fluctuations occurred during training and resulted in dissociated patterns of VO2 and respiratory exchange ratio (RER). These fluctuations further resulted in significantly greater VO2 coefficient of variation and RER values and lower minimal VO2 values. CONCLUSIONS Quantifying respiratory performance during exercise is a potentially useful means for studying pathophysiology in mdx mice, as it assesses intact animals over time, is more sensitive than some histological markers, and assesses systemic muscle function.
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Affiliation(s)
- Andrew B Rocco
- College of Veterinary Medicine, Washington Center for Muscle Biology, Washington State University, Pullman, Washington, USA
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32
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Pratt SJP, Shah SB, Ward CW, Kerr JP, Stains JP, Lovering RM. Recovery of altered neuromuscular junction morphology and muscle function in mdx mice after injury. Cell Mol Life Sci 2014; 72:153-64. [PMID: 24947322 PMCID: PMC4282693 DOI: 10.1007/s00018-014-1663-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 05/14/2014] [Accepted: 06/02/2014] [Indexed: 12/02/2022]
Abstract
Duchenne muscular dystrophy (DMD) is a devastating neuromuscular disease in which weakness, increased susceptibility to muscle injury, and inadequate repair underlie the pathology. While most attention has focused within the muscle fiber, we recently demonstrated significant alterations in the neuromuscular junction (NMJ) morphology and resulting neuromuscular transmission failure (NTF) 24 h after injury in mdx mice (murine model for DMD). Here we determine the contribution of NMJ morphology and NTF to the recovery of muscle contractile function post-injury. NMJ morphology and NTF rates were assessed day 0 (immediately after injury) and days 1, 7, 14 and 21 after quadriceps injury. Eccentric injury of the quadriceps resulted in a significant loss of maximal torque in both WT (39 ± 6 %) and mdx (76 ± 8 %) with a full recovery in WT by day 7 and in mdx by day 21. Post-injury alterations in NMJ morphology and NTF were found only in mdx, were limited to days 0 and 1, and were independent of changes in MuSK or AChR expression. Such early changes at the NMJ after injury are consistent with mechanical disruption rather than newly forming NMJs. Furthermore, we show that the dense microtubule network that underlies the NMJ is significantly reduced and disorganized in mdx compared to WT. These structural changes at the NMJ may play a role in the increased NMJ disruption and the exaggerated loss of nerve-evoked muscle force seen after injury to dystrophic muscles.
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Affiliation(s)
- Stephen J. P. Pratt
- Department of Orthopaedics, University of Maryland School of Medicine, 100 Penn St. AHB, Room 540, Baltimore, MD 21201 USA
| | - Sameer B. Shah
- Department of Orthopaedic Surgery and Bioengineering, University of California, San Diego, USA
| | | | - Jaclyn P. Kerr
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
| | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, 100 Penn St. AHB, Room 540, Baltimore, MD 21201 USA
| | - Richard M. Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, 100 Penn St. AHB, Room 540, Baltimore, MD 21201 USA
- Department of Physiology, University of Maryland School of Medicine, Baltimore, USA
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Banks GB, Combs AC, Odom GL, Bloch RJ, Chamberlain JS. Muscle structure influences utrophin expression in mdx mice. PLoS Genet 2014; 10:e1004431. [PMID: 24922526 PMCID: PMC4055409 DOI: 10.1371/journal.pgen.1004431] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2014] [Accepted: 04/24/2014] [Indexed: 02/04/2023] Open
Abstract
Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder caused by mutations in the dystrophin gene. To examine the influence of muscle structure on the pathogenesis of DMD we generated mdx4cv:desmin double knockout (dko) mice. The dko male mice died of apparent cardiorespiratory failure at a median age of 76 days compared to 609 days for the desmin−/− mice. An ∼2.5 fold increase in utrophin expression in the dko skeletal muscles prevented necrosis in ∼91% of 1a, 2a and 2d/x fiber-types. In contrast, utrophin expression was reduced in the extrasynaptic sarcolemma of the dko fast 2b fibers leading to increased membrane fragility and dystrophic pathology. Despite lacking extrasynaptic utrophin, the dko fast 2b fibers were less dystrophic than the mdx4cv fast 2b fibers suggesting utrophin-independent mechanisms were also contributing to the reduced dystrophic pathology. We found no overt change in the regenerative capacity of muscle stem cells when comparing the wild-type, desmin−/−, mdx4cv and dko gastrocnemius muscles injured with notexin. Utrophin could form costameric striations with α-sarcomeric actin in the dko to maintain the integrity of the membrane, but the lack of restoration of the NODS (nNOS, α-dystrobrevin 1 and 2, α1-syntrophin) complex and desmin coincided with profound changes to the sarcomere alignment in the diaphragm, deposition of collagen between the myofibers, and impaired diaphragm function. We conclude that the dko mice may provide new insights into the structural mechanisms that influence endogenous utrophin expression that are pertinent for developing a therapy for DMD. Duchenne muscular dystrophy (DMD) is a severe muscle wasting disorder caused by mutations in the dystrophin gene. Utrophin is structurally similar to dystrophin and improving its expression can prevent skeletal muscle necrosis in the mdx mouse model of DMD. Consequently, improving utrophin expression is a primary therapeutic target for treating DMD. While the downstream mechanisms that influence utrophin expression and stability are well described, the upstream mechanisms are less clear. Here, we found that perturbing the highly ordered structure of striated muscle by genetically deleting desmin from mdx mice increased utrophin expression to levels that prevented skeletal muscle necrosis. Thus, the mdx:desmin double knockout mice may prove valuable in determining the upstream mechanisms that influence utrophin expression to develop a therapy for DMD.
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Affiliation(s)
- Glen B. Banks
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
- * E-mail:
| | - Ariana C. Combs
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Guy L. Odom
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
| | - Robert J. Bloch
- Department of Physiology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Jeffrey S. Chamberlain
- Department of Neurology, University of Washington, Seattle, Washington, United States of America
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Faber RM, Hall JK, Chamberlain JS, Banks GB. Myofiber branching rather than myofiber hyperplasia contributes to muscle hypertrophy in mdx mice. Skelet Muscle 2014; 4:10. [PMID: 24910770 PMCID: PMC4047439 DOI: 10.1186/2044-5040-4-10] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2014] [Accepted: 05/06/2014] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Muscle hypertrophy in the mdx mouse model of Duchenne muscular dystrophy (DMD) can partially compensate for the loss of dystrophin by maintaining peak force production. Histopathology examination of the hypertrophic muscles suggests the hypertrophy primarily results from the addition of myofibers, and is accompanied by motor axon branching. However, it is unclear whether an increased number of innervated myofibers (myofiber hyperplasia) contribute to muscle hypertrophy in the mdx mice. METHODS To better understand the cellular mechanisms of muscle hypertrophy in mdx mice, we directly compared the temporal progression of the dystrophic pathology in the extensor digitorum longus (EDL) muscle to myofiber number, myofiber branching, and innervation, from 3 to 20 weeks of age. RESULTS We found that a 28% increase in the number of fibers in transverse sections of muscle correlated with a 31% increase in myofiber branching. Notably, the largest increases in myofiber number and myofiber branching occurred after 12 weeks of age when the proportion of myofibers with central nuclei had stabilized and the mdx mouse had reached maturity. The dystrophic pathology coincided with profound changes to innervation of the muscles that included temporary denervation of necrotic fibers, fragmentation of synapses, and ultra-terminal axon sprouting. However, there was little evidence of synapse formation in the mdx mice from 3 to 20 weeks of age. Only 4.4% of neuromuscular junctions extended ultra-terminal synapses, which failed to mature, and the total number of neuromuscular junctions remained constant. CONCLUSIONS Muscle hypertrophy in mdx mice results from myofiber branching rather than myofiber hyperplasia.
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Affiliation(s)
- Rachel M Faber
- Department of Neurology, University of Washington, Seattle, WA 98195-7720, USA
| | - John K Hall
- Department of Neurology, University of Washington, Seattle, WA 98195-7720, USA
| | - Jeffrey S Chamberlain
- Department of Neurology, University of Washington, Seattle, WA 98195-7720, USA ; Department of Biochemistry, University of Washington, Seattle, WA 98195-7720, USA ; Department of Medicine, University of Washington, Seattle, WA 98195-7720, USA
| | - Glen B Banks
- Department of Neurology, University of Washington, Seattle, WA 98195-7720, USA
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35
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Abstract
Duchenne muscular dystrophy (DMD) is an inherited, progressive muscle wasting disorder caused by mutations in the dystrophin gene. An increasing variety of approaches are moving towards clinical testing that all aim to restore dystrophin production and to enhance or preserve muscle mass. Gene therapy methods are being developed to replace the defective dystrophin gene or induce dystrophin production from mutant genes. Stem cell approaches are being developed to replace lost muscle cells while also bringing in new dystrophin genes. This review summarizes recent progress in the field with an emphasis on clinical applications.
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36
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Vianello S, Consolaro F, Bich C, Cancela JM, Roulot M, Lanchec E, Touboul D, Brunelle A, Israël M, Benoit E, de la Porte S. Low doses of arginine butyrate derivatives improve dystrophic phenotype and restore membrane integrity in DMD models. FASEB J 2014; 28:2603-19. [PMID: 24604079 DOI: 10.1096/fj.13-244798] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
A new approach to treating Duchenne muscular dystrophy was investigated by using the ester or amide covalent association of arginine [nitric oxide (NO) pathway] and butyrate [histone deacetylase (HDAC) inhibition] in mdx mice and patient myotubes. Two prodrugs were synthesized, and the beneficial effects on dystrophic phenotype were studied. Nerve excitability abnormalities detected in saline-treated mice were almost totally rescued in animals treated at low doses (50-100 mg/kg/d). Force and fatigue resistance were improved ≈60% and 3.5-fold, respectively, and the percentage of necrosis in heart sections was reduced ≈90% in the treated mice. A decrease of >50% in serum creatine kinase indicated an overall improvement in the muscles. Restoration of membrane integrity was studied directly by measuring the reduction (≈74%) of Evans blue incorporation in the limb muscles of the treated animals, the increase in utrophin level, and the normalization of lipid composition of the heart. In cultures of human myotubes (primary cells and cell line), both prodrugs and HDAC inhibitors increased by 2- to 4-fold the utrophin level, which was correctly localized at the membrane. β-Dystroglycan and embryonic myosin protein levels were also increased. Finally, a 50% reduction in the number of spontaneous Ca(2+) spikes was observed after treatment with NO synthase substrate and HDAC inhibitors. Overall, the beneficial effects were obtained with doses 10 (in vivo) and 5 (in vitro) times lower than those of the salt formulation. Altogether, these data constitute proof of principle of the beneficial effects of low doses of arginine butyrate derivatives on muscular dystrophy, enhancing the NO pathway and inhibiting HDAC.
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Affiliation(s)
- Sara Vianello
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
| | - Francesca Consolaro
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
| | - Claudia Bich
- Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, UPR 2301, Centre National de la Recherche Scientifique (CNRS), Gif sur Yvette, France; and
| | - José-Manuel Cancela
- Centre de Neurosciences Paris-Sud, Université Paris Sud, Unité Mixte de Recherche (UMR) 8195, CNRS, Orsay, France
| | - Morgane Roulot
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
| | - Erwan Lanchec
- Centre de Neurosciences Paris-Sud, Université Paris Sud, Unité Mixte de Recherche (UMR) 8195, CNRS, Orsay, France
| | - David Touboul
- Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, UPR 2301, Centre National de la Recherche Scientifique (CNRS), Gif sur Yvette, France; and
| | - Alain Brunelle
- Institut de Chimie des Substances Naturelles, Centre de Recherche de Gif, UPR 2301, Centre National de la Recherche Scientifique (CNRS), Gif sur Yvette, France; and
| | - Maurice Israël
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
| | - Evelyne Benoit
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
| | - Sabine de la Porte
- Neurobiologie and Développement, Institut de Neurobiologie Alfred Fessard-Fédération pour la Recherche sur le Cerveau (FRC) 2118, Unité Propres de Recherche (UPR) 3294, and
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Koo T, Popplewell L, Athanasopoulos T, Dickson G. Triple trans-splicing adeno-associated virus vectors capable of transferring the coding sequence for full-length dystrophin protein into dystrophic mice. Hum Gene Ther 2013; 25:98-108. [PMID: 24191945 DOI: 10.1089/hum.2013.164] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors have been shown to permit very efficient widespread transgene expression in skeletal muscle after systemic delivery, making these increasingly attractive as vectors for Duchenne muscular dystrophy (DMD) gene therapy. DMD is a severe muscle-wasting disorder caused by DMD gene mutations leading to complete loss of dystrophin protein. One of the major issues associated with delivery of the DMD gene, as a therapeutic approach for DMD, is its large open reading frame (ORF; 11.1 kb). A series of truncated microdystrophin cDNAs (delivered via a single AAV) and minidystrophin cDNAs (delivered via dual-AAV trans-spliced/overlapping reconstitution) have thus been extensively tested in DMD animal models. However, critical rod and hinge domains of dystrophin required for interaction with components of the dystrophin-associated protein complex, such as neuronal nitric oxide synthase, syntrophin, and dystrobrevin, are missing; these dystrophin domains may still need to be incorporated to increase dystrophin functionality and stabilize membrane rigidity. Full-length DMD gene delivery using AAV vectors remains elusive because of the limited single-AAV packaging capacity (4.7 kb). Here we developed a novel method for the delivery of the full-length DMD coding sequence to skeletal muscles in dystrophic mdx mice using a triple-AAV trans-splicing vector system. We report for the first time that three independent AAV vectors carrying "in tandem" sequential exonic parts of the human DMD coding sequence enable the expression of the full-length protein as a result of trans-splicing events cojoining three vectors via their inverted terminal repeat sequences. This method of triple-AAV-mediated trans-splicing could be applicable to the delivery of any large therapeutic gene (≥11 kb ORF) into postmitotic tissues (muscles or neurons) for the treatment of various inherited metabolic and genetic diseases.
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Affiliation(s)
- Taeyoung Koo
- 1 School of Biological Sciences, Royal Holloway University of London , Surrey TW20 0EX, United Kingdom
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Robinson KG, Mendonca JL, Militar JL, Theroux MC, Dabney KW, Shah SA, Miller F, Akins RE. Disruption of basal lamina components in neuromotor synapses of children with spastic quadriplegic cerebral palsy. PLoS One 2013; 8:e70288. [PMID: 23976945 PMCID: PMC3745387 DOI: 10.1371/journal.pone.0070288] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2012] [Accepted: 06/18/2013] [Indexed: 11/18/2022] Open
Abstract
Cerebral palsy (CP) is a static encephalopathy occurring when a lesion to the developing brain results in disordered movement and posture. Patients present with sometimes overlapping spastic, athetoid/dyskinetic, and ataxic symptoms. Spastic CP, which is characterized by stiff muscles, weakness, and poor motor control, accounts for ∼80% of cases. The detailed mechanisms leading to disordered movement in spastic CP are not completely understood, but clinical experience and recent studies suggest involvement of peripheral motor synapses. For example, it is recognized that CP patients have altered sensitivities to drugs that target neuromuscular junctions (NMJs), and protein localization studies suggest that NMJ microanatomy is disrupted in CP. Since CP originates during maturation, we hypothesized that NMJ disruption in spastic CP is associated with retention of an immature neuromotor phenotype later in life. Scoliosis patients with spastic CP or idiopathic disease were enrolled in a prospective, partially-blinded study to evaluate NMJ organization and neuromotor maturation. The localization of synaptic acetylcholine esterase (AChE) relative to postsynaptic acetylcholine receptor (AChR), synaptic laminin β2, and presynaptic vesicle protein 2 (SV2) appeared mismatched in the CP samples; whereas, no significant disruption was found between AChR and SV2. These data suggest that pre- and postsynaptic NMJ components in CP children were appropriately distributed even though AChE and laminin β2 within the synaptic basal lamina appeared disrupted. Follow up electron microscopy indicated that NMJs from CP patients appeared generally mature and similar to controls with some differences present, including deeper postsynaptic folds and reduced presynaptic mitochondria. Analysis of maturational markers, including myosin, syntrophin, myogenin, and AChR subunit expression, and telomere lengths, all indicated similar levels of motor maturation in the two groups. Thus, NMJ disruption in CP was found to principally involve components of the synaptic basal lamina and subtle ultra-structural modifications but appeared unrelated to neuromotor maturational status.
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Affiliation(s)
- Karyn G. Robinson
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Janet L. Mendonca
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Jaimee L. Militar
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Mary C. Theroux
- Department of Anesthesiology and Critical Care, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Kirk W. Dabney
- Department of Orthopedic Surgery, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Suken A. Shah
- Department of Orthopedic Surgery, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Freeman Miller
- Department of Orthopedic Surgery, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
| | - Robert E. Akins
- Nemours Biomedical Research, Alfred I. duPont Hospital for Children, Wilmington, Delaware, United States of America
- * E-mail:
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Lovering RM, Brooks SV. Eccentric exercise in aging and diseased skeletal muscle: good or bad? J Appl Physiol (1985) 2013; 116:1439-45. [PMID: 23471953 DOI: 10.1152/japplphysiol.00174.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Evidence is accumulating regarding the benefits of exercise in people who are more susceptible to injury, such as the elderly, or those with a neuromuscular disease, for example Duchenne muscular dystrophy (DMD). There appears to be a consensus that exercise can be safely performed in aging and diseased muscles, but the role of eccentric exercise is not as clear. Eccentric (lengthening) contractions have risks and benefits. Eccentric contractions are commonly performed on a daily basis, and high-force voluntary eccentric contractions are often employed in strength training paradigms with excellent results; however, high-force eccentric contractions are also linked to muscle damage. This minireview examines the benefits and safety issues of using eccentric exercise in at-risk populations. A common recommendation for all individuals is difficult to achieve, and guidelines are still being established. Some form of exercise is generally recommended with aging and even with diseased muscles, but the prescription (frequency, intensity, and duration) and type (resistance vs. aerobic) of exercise requires personal attention, as there is great diversity in the functional level and comorbidities in the elderly and those with neuromuscular disease.
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Affiliation(s)
- Richard M Lovering
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland; and
| | - Susan V Brooks
- Department of Molecular and Integrative Physiology, University of Michigan School of Medicine, Ann Arbor, Michigan
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Seto JT, Ramos JN, Muir L, Chamberlain JS, Odom GL. Gene replacement therapies for duchenne muscular dystrophy using adeno-associated viral vectors. Curr Gene Ther 2012; 12:139-51. [PMID: 22533379 DOI: 10.2174/156652312800840603] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2012] [Revised: 04/16/2012] [Accepted: 04/17/2012] [Indexed: 12/12/2022]
Abstract
The muscular dystrophies collectively represent a major health challenge, as few significant treatment options currently exist for any of these disorders. Recent years have witnessed a proliferation of novel approaches to therapy, spanning increased testing of existing and new pharmaceuticals, DNA delivery (both anti-sense oligonucleotides and plasmid DNA), gene therapies and stem cell technologies. While none of these has reached the point of being used in clinical practice, all show promise for being able to impact different types of muscular dystrophies. Our group has focused on developing direct gene replacement strategies to treat recessively inherited forms of muscular dystrophy, particularly Duchenne and Becker muscular dystrophy (DMD/BMD). Both forms of dystrophy are caused by mutations in the dystrophin gene and all cases can in theory be treated by gene replacement using synthetic forms of the dystrophin gene. The major challenges for success of this approach are the development of a suitable gene delivery shuttle, generating a suitable gene expression cassette able to be carried by such a shuttle, and achieving safe and effective delivery without elicitation of a destructive immune response. This review summarizes the current state of the art in terms of using adeno-associated viral vectors to deliver synthetic dystrophin genes for the purpose of developing gene therapy for DMD.
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Affiliation(s)
- Jane T Seto
- Department of Neurology, University of Washington, Seattle, WA 98195-7720, USA.
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41
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Foster H, Popplewell L, Dickson G. Genetic therapeutic approaches for Duchenne muscular dystrophy. Hum Gene Ther 2012; 23:676-87. [PMID: 22647146 DOI: 10.1089/hum.2012.099] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Despite an expansive wealth of research following the discovery of the DMD gene 25 years ago, there is still no curative treatment for Duchenne muscular dystrophy. However, there are currently many promising lines of research, including cell-based therapies and pharmacological reagents to upregulate dystrophin via readthrough of nonsense mutations or by upregulation of the dystrophin homolog utrophin. Here we review genetic-based therapeutic strategies aimed at the amelioration of the DMD phenotype. These include the reintroduction of a copy of the DMD gene into an affected tissue by means of a viral vector; correction of the mutated DMD transcript by antisense oligonucleotide-induced exon skipping to restore the open reading frame; and direct modification of the DMD gene at a chromosomal level through genome editing. All these approaches are discussed in terms of the more recent advances, and the hurdles to be overcome if a comprehensive and effective treatment for DMD is to be found. These hurdles include the need to target all musculature of the body. Therefore any potential treatment would need to be administered systemically. In addition, any treatment needs to have a long-term effect, with the possibility of readministration, while avoiding any potentially detrimental immune response to the vector or transgene.
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Affiliation(s)
- Helen Foster
- School of Biological Sciences, Royal Holloway-University of London, Egham, Surrey TW20 0EX, United Kingdom
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Pratt SJP, Shah SB, Ward CW, Inacio MP, Stains JP, Lovering RM. Effects of in vivo injury on the neuromuscular junction in healthy and dystrophic muscles. J Physiol 2012; 591:559-70. [PMID: 23109110 DOI: 10.1113/jphysiol.2012.241679] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The most common and severe form of muscular dystrophy is Duchenne muscular dystrophy (DMD), a disorder caused by the absence of dystrophin, a structural protein found on the cytoplasmic surface of the sarcolemma of striated muscle fibres. Considerable attention has been dedicated to studying myofibre damage and muscle plasticity, but there is little information to determine if damage from contraction-induced injury occurs at or near the nerve terminal axon. We used α-bungarotoxin to compare neuromuscular junction (NMJ) morphology in healthy (wild-type, WT) and dystrophic (mdx) mouse quadriceps muscles and evaluated transcript levels of the post-synaptic muscle-specific kinase signalling complex. Our focus was to study changes in NMJs after injury induced with an established in vivo animal injury model. Neuromuscular transmission, electromyography (EMG), and NMJ morphology were assessed 24 h after injury. In non-injured muscle, muscle-specific kinase expression was significantly decreased in mdx compared to WT. Injury resulted in a significant loss of maximal torque in WT (39 ± 6%) and mdx (76 ± 8%) quadriceps, but significant changes in NMJ morphology, neuromuscular transmission and EMG data were found only in mdx following injury. Compared with WT mice, motor end-plates of mdx mice demonstrated less continuous morphology, more disperse acetylcholine receptor aggregates and increased number of individual acetylcholine receptor clusters, an effect that was exacerbated following injury. Neuromuscular transmission failure increased and the EMG measures decreased after injury in mdx mice only. The data show that eccentric contraction-induced injury causes morphological and functional changes to the NMJs in mdx skeletal muscle, which may play a role in excitation-contraction coupling failure and progression of the dystrophic process.
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Affiliation(s)
- Stephen J P Pratt
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
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43
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Molecular mechanisms underlying maturation and maintenance of the vertebrate neuromuscular junction. Trends Neurosci 2012; 35:441-53. [PMID: 22633140 DOI: 10.1016/j.tins.2012.04.005] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2012] [Revised: 04/09/2012] [Accepted: 04/15/2012] [Indexed: 01/22/2023]
Abstract
The vertebrate neuromuscular junction (NMJ), a peripheral synapse formed between motoneuron and skeletal muscle, is characterized by a protracted postnatal period of maturation and life-long maintenance. In neuromuscular disorders such as congenital myasthenic syndromes (CMSs), disruptions of NMJ maturation and/or maintenance are frequently observed. In particular, defective neuromuscular transmission associated with structural and molecular abnormalities at the pre- and postsynaptic membranes, as well as at the synaptic cleft, has been reported in these patients. Here, we review recent advances in the understanding of molecular and cellular events that mediate NMJ maturation and maintenance. The underlying regulatory mechanisms, including key molecular regulators at the presynaptic nerve terminal, synaptic cleft, and postsynaptic muscle membrane, are discussed.
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The absence of dystrophin rather than muscle degeneration causes acetylcholine receptor cluster defects in dystrophic muscle. Neuroreport 2012; 23:82-7. [PMID: 22124255 DOI: 10.1097/wnr.0b013e32834e7e54] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Duchenne muscular dystrophy is the most common genetic muscle disease. Affected muscles are characterized by abnormal acetylcholine receptor (AChR) clustering. Some studies have suggested that changes in AChR clusters are secondary to degenerative processes. In this study, we demonstrate that AChR cluster fragmentation and muscle degeneration are separate events. We compared AChR clusters and pathological features in mdx mice (mutated dystrophin) and dko mice (mutated dystrophin and utrophin). AChR clusters were identified by binding with α-bungarotoxin, and pathological features were observed by classical immunohistochemical techniques. AChR clusters in mdx and dko mice were reduced in number and exhibited structural fragmentation. However, AChR cluster fragmentation was not significantly different in mdx and dko mice, although more severe inflammatory infiltration and degeneration were observed in dko mice. Furthermore, neuronal nitric oxide synthase, which interacts with dystrophin to anchor itself at the sarcolemma, was notably reduced in mdx and dko mice. Fragmentation of AChR and muscle degeneration are separate events, and both are secondary results of destabilization on the sarcolemma and the cytoskeleton.
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Changes in aging mouse neuromuscular junctions are explained by degeneration and regeneration of muscle fiber segments at the synapse. J Neurosci 2011; 31:14910-9. [PMID: 22016524 DOI: 10.1523/jneurosci.3590-11.2011] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Vertebrate neuromuscular junctions are highly stable synapses, retaining the morphology they achieve in early postnatal development throughout most of life. However, these synapses undergo dramatic change during aging. The acetylcholine receptors (AChRs) change from smooth gutters into fragmented islands, and the nerve terminals change similarly to be varicosities apposed to these islands. These changes have been attributed to a slow deterioration in mechanisms maintaining the synapse. We have used repeated, vital imaging to investigate how these changes occur in the sternomastoid muscle of aging mice. We have found, contrary to expectation, that individual junctions change infrequently, but change, when it occurs, is sudden and dramatic. The change mimics that reported previously for cases in which muscle fibers are deliberately damaged: most of the AChRs present disappear rapidly and are replaced by a new set of receptors that become fragmented. The fiber segment underneath the synapse has centrally located nuclei, showing that this segment has undergone necrosis, quickly regenerated, and been reinnervated with an altered synapse. We show that necrotic events are common in aged muscle and have likely been missed previously as a cause of the alterations in aging because central nuclei are a transient phenomenon and the necrotic events at the junction infrequent. However, the changes are permanent and accumulate over time. Interventions to reduce the neuromuscular changes during aging should likely focus on making muscle fibers resistant to injury.
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Akima H, Lott D, Senesac C, Deol J, Germain S, Arpan I, Bendixen R, Lee Sweeney H, Walter G, Vandenborne K. Relationships of thigh muscle contractile and non-contractile tissue with function, strength, and age in boys with Duchenne muscular dystrophy. Neuromuscul Disord 2011; 22:16-25. [PMID: 21807516 DOI: 10.1016/j.nmd.2011.06.750] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Revised: 05/16/2011] [Accepted: 06/27/2011] [Indexed: 10/17/2022]
Abstract
The purpose of this study was to assess the contractile and non-contractile content in thigh muscles of patients with Duchenne muscular dystrophy (DMD) and determine the relationship with functional abilities. Magnetic resonance images of the thigh were acquired in 28 boys with DMD and 10 unaffected boys. Muscle strength, timed functional tests, and the Brookes Lower Extremity scale were also assessed. Non-contractile content in the DMD group was significantly greater than in the control group for six muscles, including rectus femoris, biceps femoris-long head and adductor magnus. Non-contractile content in the total thigh musculature assessed by MRI correlated with the Brookes scale (r(s)=0.75) and supine-up test (r(s)=0.68), as well as other functional measures. An age-related specific torque increase was observed in the control group (r(s)=0.96), but not the DMD (r(s)=0.06). These findings demonstrate that MRI measures of contractile and non-contractile content can provide important information about disease progression in DMD.
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Affiliation(s)
- Hiroshi Akima
- Department of Physical Therapy, University of Florida, Gainesville, FL 32610, USA.
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Pichavant C, Chapdelaine P, Cerri DG, Bizario JCS, Tremblay JP. Electrotransfer of the full-length dog dystrophin into mouse and dystrophic dog muscles. Hum Gene Ther 2011; 21:1591-601. [PMID: 20553115 DOI: 10.1089/hum.2010.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked genetic disease characterized by the absence of dystrophin (427 kDa). An approach to eventually restore this protein in patients with DMD is to introduce into their muscles a plasmid encoding dystrophin cDNA. Because the phenotype of the dystrophic dog is closer to the human phenotype than is the mdx mouse phenotype, we have studied the electrotransfer of a plasmid carrying the full-length dog dystrophin (FLDYS(dog)) in dystrophic dog muscle. To achieve this nonviral delivery, the FLDYS(dog) cDNA was cloned in two plasmids containing either a cytomegalovirus or a muscle creatine kinase promoter. In both cases, our results showed that the electrotransfer of these large plasmids (∼17 kb) into mouse muscle allowed FLDYS(dog) expression in the treated muscle. The electrotransfer of pCMV.FLDYS(dog) in a dystrophic dog muscle also led to the expression of dystrophin. In conclusion, introduction of the full-length dog dystrophin cDNA by electrotransfer into dystrophic dog muscle is a potential approach to restore dystrophin in patients with DMD. However, the electrotransfer procedure should be improved before applying it to humans.
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Affiliation(s)
- Christophe Pichavant
- Unité de Recherche en Génétique Humaine, Centre de Recherche du Centre Hospitalier de l'Université Laval, Centre Hospitalier Universitaire de Québec, and Faculté de Médecine, Université Laval, Sainte-Foy, Québec, Canada
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Ferretti R, Neto HS, Marques MJ. Expression of utrophin at dystrophin-deficient neuromuscular synapses of mdx mice: a study of protected and affected muscles. Anat Rec (Hoboken) 2010; 294:283-6. [PMID: 21235003 DOI: 10.1002/ar.21297] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Revised: 08/27/2010] [Accepted: 09/29/2010] [Indexed: 11/06/2022]
Abstract
In mdx mice, intrinsic laryngeal muscles are spared and sternomastoid muscles are affected, showing cycles of muscle regeneration. We observed that utrophin and acetylcholine receptors are fragmented only in affected muscles, providing further evidence that changes in the overall distribution of molecules at dystrophic neuromuscular junctions may be correlated with muscle regeneration.
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Affiliation(s)
- Renato Ferretti
- Department of Anatomy, Cell Biology, Physiology and Biophysics, Institute of Biology, State University of Campinas (UNICAMP), Campinas, São Paulo 13083-970, Brazil
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Odom GL, Banks GB, Schultz BR, Gregorevic P, Chamberlain JS. Preclinical studies for gene therapy of Duchenne muscular dystrophy. J Child Neurol 2010; 25:1149-57. [PMID: 20498332 DOI: 10.1177/0883073810371006] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The muscular dystrophies are a diverse group of genetic disorders without an effective treatment. Because they are caused by mutations in various genes, the most direct way to treat them involves correcting the underlying gene defect (ie, gene therapy). Such a gene therapy approach involves delivering a therapeutic gene cassette to essentially all the muscles of the body in a safe and efficacious manner. The authors describe gene delivery methods using vectors derived from adeno-associated virus that are showing great promise in preclinical studies for treatment of Duchenne muscular dystrophy. It is hoped that variations on these methods might be applicable for most, if not all, of the different types of muscular dystrophy.
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Affiliation(s)
- Guy L Odom
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington 98195-7720, USA
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50
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Dystrophin: more than just the sum of its parts. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2010; 1804:1713-22. [PMID: 20472103 DOI: 10.1016/j.bbapap.2010.05.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/30/2010] [Accepted: 05/03/2010] [Indexed: 01/05/2023]
Abstract
Dystrophin is one of a number of large cytoskeleton associated proteins that connect between various cytoskeletal elements and often are tethered to the membrane through other transmembrane protein complexes. These cytolinker proteins often provide structure and support to the cells where they are expressed, and mutations in genes encoding these proteins frequently gives rise to disease. Dystrophin is no exception in any of these respects, providing connections between a transmembrane complex known as the dystrophin-glycoprotein complex and the underlying cytoskeleton. The most established connection and possibly the most important is that to F-actin, but more recently evidence has been forthcoming of connections to membrane phospholipids, intermediate filaments and microtubules. Moreover it is becoming increasingly clear that the multiple spectrin-like repeats in the centre of the molecule, that had hitherto been thought to be largely redundant, harbour binding activities that have a significant impact on dystrophin functionality. This functionality is particularly apparent when assessed by the ability to rescue the dystrophic phenotype in mdx mice. This review will focus on the relatively neglected but functionally vital coiled-coil region of dystrophin, highlighting the structural relationships and interactions of the coiled-coil region and providing new insights into the functional role of this region.
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