1
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Liu Y, Lin W. Morphological and functional alterations of neuromuscular synapses in a mouse model of ACTA1 congenital myopathy. Hum Mol Genet 2024; 33:233-244. [PMID: 37883471 PMCID: PMC10800017 DOI: 10.1093/hmg/ddad183] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/09/2023] [Accepted: 10/20/2023] [Indexed: 10/28/2023] Open
Abstract
Mutations in skeletal muscle α-actin (Acta1) cause myopathies. In a mouse model of congenital myopathy, heterozygous Acta1 (H40Y) knock-in (Acta1+/Ki) mice exhibit features of human nemaline myopathy, including premature lethality, severe muscle weakness, reduced mobility, and the presence of nemaline rods in muscle fibers. In this study, we investigated the impact of Acta1 (H40Y) mutation on the neuromuscular junction (NMJ). We found that the NMJs were markedly fragmented in Acta1+/Ki mice. Electrophysiological analysis revealed a decrease in amplitude but increase in frequency of miniature end-plate potential (mEPP) at the NMJs in Acta1+/Ki mice, compared with those in wild type (Acta1+/+) mice. Evoked end-plate potential (EPP) remained similar at the NMJs in Acta1+/Ki and Acta1+/+ mice, but quantal content was increased at the NMJs in Acta1+/Ki, compared with Acta1+/+ mice, suggesting a homeostatic compensation at the NMJs in Acta1+/Ki mice to maintain normal levels of neurotransmitter release. Furthermore, short-term synaptic plasticity of the NMJs was compromised in Acta1+/Ki mice. Together, these results demonstrate that skeletal Acta1 H40Y mutation, albeit muscle-origin, leads to both morphological and functional defects at the NMJ.
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Affiliation(s)
- Yun Liu
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
| | - Weichun Lin
- Department of Neuroscience, University of Texas Southwestern Medical Center, 6000 Harry Hines Blvd, Dallas, TX 75390-9111, United States
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2
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Iannuzzo F, Cicatiello AG, Sagliocchi S, Schiano E, Nappi A, Miro C, Stornaiuolo M, Mollica A, Tenore GC, Dentice M, Novellino E. Therapeutic Effect of an Ursolic Acid-Based Nutraceutical on Neuronal Regeneration after Sciatic Nerve Injury. Int J Mol Sci 2024; 25:902. [PMID: 38255977 PMCID: PMC10815361 DOI: 10.3390/ijms25020902] [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: 12/05/2023] [Revised: 01/08/2024] [Accepted: 01/10/2024] [Indexed: 01/24/2024] Open
Abstract
Peripheral nerve injuries lead to severe functional impairments and long recovery times, with limited effectiveness and accessibility of current treatments. This has increased interest in natural bioactive compounds, such as ursolic acid (UA). Our study evaluated the effect of an oleolyte rich in UA from white grape pomace (WGPO) on neuronal regeneration in mice with induced sciatic nerve resection, administered concurrently with the induced damage (the WGPO group) and 10 days prior (the PRE-WGPO group). The experiment was monitored at two-time points (4 and 10 days) after injury. After 10 days, the WGPO group demonstrated a reduction in muscle atrophy, evidenced by an increased number and diameter of muscle fibers and a decreased Atrogin-1 and Murf-1 expression relative to the denervated control. It was also observed that 85.7% of neuromuscular junctions (NMJs) were fully innervated, as indicated by the colocalization of α-bungarotoxin and synaptophysin, along with the significant modulation of Oct-6 and S-100. The PRE-WGPO group showed a more beneficial effect on nerve fiber reformation, with a significant increase in myelin protein zero and 95.2% fully innervated NMJs, and a pro-hypertrophic effect in resting non-denervated muscles. Our findings suggest WGPO as a potential treatment for various conditions that require the repair of nerve and muscle injuries.
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Affiliation(s)
- Fortuna Iannuzzo
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (F.I.); (A.M.)
| | - Annunziata Gaetana Cicatiello
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Napoli, Italy; (A.G.C.); (S.S.); (A.N.); (C.M.)
| | - Serena Sagliocchi
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Napoli, Italy; (A.G.C.); (S.S.); (A.N.); (C.M.)
| | - Elisabetta Schiano
- Healthcare Food Research Center, Inventia Biotech s.r.l., S. S. Sannitica, 81020 Caserta, Italy; (E.S.); (E.N.)
| | - Annarita Nappi
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Napoli, Italy; (A.G.C.); (S.S.); (A.N.); (C.M.)
| | - Caterina Miro
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Napoli, Italy; (A.G.C.); (S.S.); (A.N.); (C.M.)
| | - Mariano Stornaiuolo
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 59, 80131 Napoli, Italy; (M.S.); (G.C.T.)
| | - Adriano Mollica
- Department of Pharmacy, G. d’Annunzio University of Chieti-Pescara, 66100 Chieti, Italy; (F.I.); (A.M.)
| | - Gian Carlo Tenore
- Department of Pharmacy, University of Naples Federico II, Via Domenico Montesano 59, 80131 Napoli, Italy; (M.S.); (G.C.T.)
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Napoli, Italy; (A.G.C.); (S.S.); (A.N.); (C.M.)
| | - Ettore Novellino
- Healthcare Food Research Center, Inventia Biotech s.r.l., S. S. Sannitica, 81020 Caserta, Italy; (E.S.); (E.N.)
- Faculty of Medicine and Surgery, Catholic University of the Sacred Heart, 00168 Roma, Italy
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3
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Suárez-Calvet X, Fernández-Simón E, Natera D, Jou C, Pinol-Jurado P, Villalobos E, Ortez C, Monceau A, Schiava M, Codina A, Verdu-Díaz J, Clark J, Laidler Z, Mehra P, Gokul-Nath R, Alonso-Perez J, Marini-Bettolo C, Tasca G, Straub V, Guglieri M, Nascimento A, Diaz-Manera J. Decoding the transcriptome of Duchenne muscular dystrophy to the single nuclei level reveals clinical-genetic correlations. Cell Death Dis 2023; 14:596. [PMID: 37673877 PMCID: PMC10482944 DOI: 10.1038/s41419-023-06103-5] [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: 03/22/2023] [Revised: 08/15/2023] [Accepted: 08/22/2023] [Indexed: 09/08/2023]
Abstract
Duchenne muscular dystrophy is a genetic disease produced by mutations in the dystrophin gene characterized by early onset muscle weakness leading to severe and irreversible disability. The cellular and molecular consequences of the lack of dystrophin in humans are only partially known, which is crucial for the development of new therapies aiming to slow or stop the progression of the disease. Here we have analyzed quadriceps muscle biopsies of seven DMD patients aged 2 to 4 years old and five age and gender matched controls using single nuclei RNA sequencing (snRNAseq) and correlated the results obtained with clinical data. SnRNAseq identified significant differences in the proportion of cell population present in the muscle samples, including an increase in the number of regenerative fibers, satellite cells, and fibro-adipogenic progenitor cells (FAPs) and a decrease in the number of slow fibers and smooth muscle cells. Muscle samples from the younger patients with stable mild weakness were characterized by an increase in regenerative fibers, while older patients with moderate and progressive weakness were characterized by loss of muscle fibers and an increase in FAPs. An analysis of the gene expression profile in muscle fibers identified a strong regenerative signature in DMD samples characterized by the upregulation of genes involved in myogenesis and muscle hypertrophy. In the case of FAPs, we observed upregulation of genes involved in the extracellular matrix regeneration but also several signaling pathways. Indeed, further analysis of the potential intercellular communication profile showed a dysregulation of the communication profile in DMD samples identifying FAPs as a key regulator of cell signaling in DMD muscle samples. In conclusion, our study has identified significant differences at the cellular and molecular levels in the different cell populations present in skeletal muscle samples of patients with DMD compared to controls.
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Affiliation(s)
- Xavier Suárez-Calvet
- Neuromuscular Diseases Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica Sant Pau (IIB SANT PAU), 08041, Barcelona, Spain
| | - Esther Fernández-Simón
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Daniel Natera
- Neuromuscular Disorders Unit. Neurology department, Hospital Sant Joan de Deu, Esplugues de Llobregat, Spain
| | - Cristina Jou
- Pathology department, Hospital Sant Joan de Deu, Esplugues de Llobregat, Spain
| | - Patricia Pinol-Jurado
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Elisa Villalobos
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Carlos Ortez
- Neuromuscular Disorders Unit. Neurology department, Hospital Sant Joan de Deu, Esplugues de Llobregat, Spain
| | - Alexandra Monceau
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Marianela Schiava
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Anna Codina
- Pathology department, Hospital Sant Joan de Deu, Esplugues de Llobregat, Spain
| | - José Verdu-Díaz
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - James Clark
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Zoe Laidler
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Priyanka Mehra
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Rasya Gokul-Nath
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Jorge Alonso-Perez
- Neuromuscular Disease Unit. Neurology Department. Hospital Nuestra Señora de Candelaria, Fundación Canaria Instituto de Investigación Sanitaria de Canarias (FIISC), Tenerife, Spain
| | - Chiara Marini-Bettolo
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Giorgio Tasca
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Volker Straub
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Michela Guglieri
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK
| | - Andrés Nascimento
- Neuromuscular Disorders Unit. Neurology department, Hospital Sant Joan de Deu, Esplugues de Llobregat, Spain
| | - Jordi Diaz-Manera
- Neuromuscular Diseases Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Institut d'Investigació Biomèdica Sant Pau (IIB SANT PAU), 08041, Barcelona, Spain.
- John Walton Muscular Dystrophy Research Center, Newcastle University Translational and Clinical Research Institute, Newcastle Upon Tyne, UK.
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4
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Sahota VK, Stone A, Woodling NS, Spiers JG, Steinert JR, Partridge L, Augustin H. Plum modulates Myoglianin and regulates synaptic function in D. melanogaster. Open Biol 2023; 13:230171. [PMID: 37699519 PMCID: PMC10497343 DOI: 10.1098/rsob.230171] [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: 06/03/2023] [Accepted: 08/14/2023] [Indexed: 09/14/2023] Open
Abstract
Alterations in the neuromuscular system underlie several neuromuscular diseases and play critical roles in the development of sarcopenia, the age-related loss of muscle mass and function. Mammalian Myostatin (MST) and GDF11, members of the TGF-β superfamily of growth factors, are powerful regulators of muscle size in both model organisms and humans. Myoglianin (MYO), the Drosophila homologue of MST and GDF11, is a strong inhibitor of synaptic function and structure at the neuromuscular junction in flies. Here, we identified Plum, a transmembrane cell surface protein, as a modulator of MYO function in the larval neuromuscular system. Reduction of Plum in the larval body-wall muscles abolishes the previously demonstrated positive effect of attenuated MYO signalling on both muscle size and neuromuscular junction structure and function. In addition, downregulation of Plum on its own results in decreased synaptic strength and body weight, classifying Plum as a (novel) regulator of neuromuscular function and body (muscle) size. These findings offer new insights into possible regulatory mechanisms behind ageing- and disease-related neuromuscular dysfunctions in humans and identify potential targets for therapeutic interventions.
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Affiliation(s)
- Virender K. Sahota
- Department of Biological Sciences, Centre for Biomedical Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Aelfwin Stone
- Faculty of Medicine & Health Sciences, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Nathaniel S. Woodling
- Department of Biological Sciences, Centre for Biomedical Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
| | - Jereme G. Spiers
- Faculty of Medicine & Health Sciences, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Joern R. Steinert
- Faculty of Medicine & Health Sciences, Queen's Medical Centre, Nottingham NG7 2UH, UK
| | - Linda Partridge
- Institute of Healthy Ageing, and GEE, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, Cologne 50931, Germany
| | - Hrvoje Augustin
- Department of Biological Sciences, Centre for Biomedical Sciences, Royal Holloway University of London, Egham, Surrey TW20 0EX, UK
- Institute of Healthy Ageing, and GEE, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
- Max Planck Institute for Biology of Ageing, Joseph-Stelzmann-Str. 9b, Cologne 50931, Germany
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5
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Muscle 4EBP1 activation modifies the structure and function of the neuromuscular junction in mice. Nat Commun 2022; 13:7792. [PMID: 36526657 PMCID: PMC9758177 DOI: 10.1038/s41467-022-35547-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 12/09/2022] [Indexed: 12/23/2022] Open
Abstract
Dysregulation of mTOR complex 1 (mTORC1) activity drives neuromuscular junction (NMJ) structural instability during aging; however, downstream targets mediating this effect have not been elucidated. Here, we investigate the roles of two mTORC1 phosphorylation targets for mRNA translation, ribosome protein S6 kinase 1 (S6K1) and eukaryotic translation initiation factor 4E-binding protein 1 (4EBP1), in regulating NMJ structural instability induced by aging and sustained mTORC1 activation. While myofiber-specific deletion of S6k1 has no effect on NMJ structural integrity, 4EBP1 activation in murine muscle induces drastic morphological remodeling of the NMJ with enhancement of synaptic transmission. Mechanistically, structural modification of the NMJ is attributed to increased satellite cell activation and enhanced post-synaptic acetylcholine receptor (AChR) turnover upon 4EBP1 activation. Considering that loss of post-synaptic myonuclei and reduced NMJ turnover are features of aging, targeting 4EBP1 activation could induce NMJ renewal by expanding the pool of post-synaptic myonuclei as an alternative intervention to mitigate sarcopenia.
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6
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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: 0] [Impact Index Per Article: 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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7
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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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8
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Fogarty MJ, Khurram OU, Mantilla CB, Sieck GC. Brain derived neurotrophic factor/tropomyosin related kinase B signaling impacts diaphragm neuromuscular transmission in a novel rat chemogenetic model. Front Cell Neurosci 2022; 16:1025463. [PMID: 36385943 PMCID: PMC9650098 DOI: 10.3389/fncel.2022.1025463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 10/12/2022] [Indexed: 11/29/2022] Open
Abstract
The neuromuscular junction (NMJ) mediates neural control of skeletal muscle fibers. Neurotrophic signaling, specifically brain derived neurotrophic factor (BDNF) acting through its high-affinity tropomyosin related kinase B (TrkB) receptor is known to improve neuromuscular transmission. BDNF/TrkB signaling also maintains the integrity of antero- and retrograde communication between the motor neuron soma, its distal axons and pre-synaptic terminals and influences neuromuscular transmission. In this study, we employed a novel rat chemogenetic mutation (TrkB F616), in which a 1-naphthylmethyl phosphoprotein phosphatase 1 (1NMPP1) sensitive knock-in allele allowed specific, rapid and sustained inhibition of TrkB kinase activity. In adult female and male TrkB F616 rats, treatment with either 1NMPP1 (TrkB kinase inhibition) or DMSO (vehicle) was administered in drinking water for 14 days. To assess the extent of neuromuscular transmission failure (NMTF), diaphragm muscle isometric force evoked by nerve stimulation at 40 Hz (330 ms duration trains repeated each s) was compared to isometric forces evoked by superimposed direct muscle stimulation (every 15 s). Chronic TrkB kinase inhibition (1NMPP1 group) markedly worsened NMTF compared to vehicle controls. Acute BDNF treatment did not rescue NMTF in the 1NMPP1 group. Chronic TrkB kinase inhibition did not affect the apposition of pre-synaptic terminals (labeled with synaptophysin) and post-synaptic endplates (labeled with α-Bungarotoxin) at diaphragm NMJs. We conclude that inhibition of BDNF/TrkB signaling in TrkB F616 rats disrupts diaphragm neuromuscular transmission in a similar manner to TrkB F616A mice, likely via a pre-synaptic mechanism independent of axonal branch point failure.
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Affiliation(s)
- Matthew J. Fogarty
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Obaid U. Khurram
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Carlos B. Mantilla
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
| | - Gary C. Sieck
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States
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9
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Hulen J, Kenny D, Black R, Hallgren J, Hammond KG, Bredahl EC, Wickramasekara RN, Abel PW, Stessman HAF. KMT5B is required for early motor development. Front Genet 2022; 13:901228. [PMID: 36035149 PMCID: PMC9411648 DOI: 10.3389/fgene.2022.901228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Accepted: 07/11/2022] [Indexed: 11/13/2022] Open
Abstract
Disruptive variants in lysine methyl transferase 5B (KMT5B/SUV4-20H1) have been identified as likely-pathogenic among humans with neurodevelopmental phenotypes including motor deficits (i.e., hypotonia and motor delay). However, the role that this enzyme plays in early motor development is largely unknown. Using a Kmt5b gene trap mouse model, we assessed neuromuscular strength, skeletal muscle weight (i.e., muscle mass), neuromuscular junction (NMJ) structure, and myofiber type, size, and distribution. Tests were performed over developmental time (postnatal days 17 and 44) to represent postnatal versus adult structures in slow- and fast-twitch muscle types. Prior to the onset of puberty, slow-twitch muscle weight was significantly reduced in heterozygous compared to wild-type males but not females. At the young adult stage, we identified decreased neuromuscular strength, decreased skeletal muscle weights (both slow- and fast-twitch), increased NMJ fragmentation (in slow-twitch muscle), and smaller myofibers in both sexes. We conclude that Kmt5b haploinsufficiency results in a skeletal muscle developmental deficit causing reduced muscle mass and body weight.
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Affiliation(s)
- Jason Hulen
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Dorothy Kenny
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Rebecca Black
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Jodi Hallgren
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Kelley G. Hammond
- Department of Exercise Science, College of Arts and Sciences, Creighton University, Omaha, NE, United States
| | - Eric C. Bredahl
- Department of Exercise Science, College of Arts and Sciences, Creighton University, Omaha, NE, United States
| | - Rochelle N. Wickramasekara
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
- Molecular Diagnostic Laboratory, Boys Town National Research Hospital, Omaha, NE, United States
| | - Peter W. Abel
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
| | - Holly A. F. Stessman
- Department of Pharmacology and Neuroscience, School of Medicine, Creighton University, Omaha, NE, United States
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10
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Giakoumaki I, Pollock N, Aljuaid T, Sannicandro AJ, Alameddine M, Owen E, Myrtziou I, Ozanne SE, Kanakis I, Goljanek-Whysall K, Vasilaki A. Postnatal Protein Intake as a Determinant of Skeletal Muscle Structure and Function in Mice-A Pilot Study. Int J Mol Sci 2022; 23:8815. [PMID: 35955948 PMCID: PMC9369224 DOI: 10.3390/ijms23158815] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2022] [Revised: 07/26/2022] [Accepted: 07/27/2022] [Indexed: 12/04/2022] Open
Abstract
Sarcopenia is characterised by an age-related decrease in the number of muscle fibres and additional weakening of the remaining fibres, resulting in a reduction in muscle mass and function. Many studies associate poor maternal nutrition during gestation and/or lactation with altered skeletal muscle homeostasis in the offspring and the development of sarcopenia. The aim of this study was to determine whether the musculoskeletal physiology in offspring born to mouse dams fed a low-protein diet during pregnancy was altered and whether any physiological changes could be modulated by the nutritional protein content in early postnatal stages. Thy1-YFP female mice were fed ad libitum on either a normal (20%) or a low-protein (5%) diet. Newborn pups were cross-fostered to different lactating dams (maintained on a 20% or 5% diet) to generate three groups analysed at weaning (21 days): Normal-to-Normal (NN), Normal-to-Low (NL) and Low-to-Normal (LN). Further offspring were maintained ad libitum on the same diet as during lactation until 12 weeks of age, creating another three groups (NNN, NLL, LNN). Mice on a low protein diet postnatally (NL, NLL) exhibited a significant reduction in body and muscle weight persisting up to 12 weeks, unlike mice on a low protein diet only prenatally (LN, LNN). Muscle fibre size was reduced in mice from the NL but not LN group, showing recovery at 12 weeks of age. Muscle force was reduced in NLL mice, concomitant with changes in the NMJ site and changes in atrophy-related and myosin genes. In addition, μCT scans of mouse tibiae at 12 weeks of age revealed changes in bone mass and morphology, resulting in a higher bone mass in the NLL group than the control NNN group. Finally, changes in the expression of miR-133 in the muscle of NLL mice suggest a regulatory role for this microRNA in muscle development in response to postnatal diet changes. Overall, this data shows that a low maternal protein diet and early postnatal life low-protein intake in mice can impact skeletal muscle physiology and function in early life while postnatal low protein diet favours bone integrity in adulthood.
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Affiliation(s)
- Ifigeneia Giakoumaki
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Natalie Pollock
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
- The MRC—Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), University of Liverpool, Liverpool L7 8TX, UK
| | - Turki Aljuaid
- Department of Physiology, School of Medicine and REMEDI, CMNHS, NUI Galway, H91 TK33 Galway, Ireland
- Department of Biotechnology, College of Science, Taif University, Taif 21944, Saudi Arabia
| | - Anthony J. Sannicandro
- Department of Physiology, School of Medicine and REMEDI, CMNHS, NUI Galway, H91 TK33 Galway, Ireland
| | - Moussira Alameddine
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Euan Owen
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Ioanna Myrtziou
- Chester Medical School, University of Chester, Bache Hall, Countess View, Chester CH2 1BR, UK
| | - Susan E. Ozanne
- University of Cambridge MRC Metabolic Diseases Unit and Metabolic Research Laboratories, Institute of Metabolic Science, Addenbrooke’s Hospital Cambridge, Cambridge CB2 0QQ, UK
| | - Ioannis Kanakis
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
- Chester Medical School, University of Chester, Bache Hall, Countess View, Chester CH2 1BR, UK
| | - Katarzyna Goljanek-Whysall
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
- The MRC—Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), University of Liverpool, Liverpool L7 8TX, UK
- Department of Physiology, School of Medicine and REMEDI, CMNHS, NUI Galway, H91 TK33 Galway, Ireland
| | - Aphrodite Vasilaki
- Department of Musculoskeletal & Ageing Science, Institute of Life Course & Medical Sciences, Faculty of Health & Life Sciences, University of Liverpool, Liverpool L7 8TX, UK
- The MRC—Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), University of Liverpool, Liverpool L7 8TX, UK
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11
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Chakravorty A, Sharma A, Sheeba V, Manjithaya R. Glutamatergic Synapse Dysfunction in Drosophila Neuromuscular Junctions Can Be Rescued by Proteostasis Modulation. Front Mol Neurosci 2022; 15:842772. [PMID: 35909443 PMCID: PMC9337869 DOI: 10.3389/fnmol.2022.842772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 04/25/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamate is the major excitatory neurotransmitter in the nervous system, and the Drosophila glutamatergic neuromuscular junctions (NMJs) offer a tractable platform to understand excitatory synapse biology both in health and disease. Synaptopathies are neurodegenerative diseases that are associated with synaptic dysfunction and often display compromised proteostasis. One such rare, progressive neurodegenerative condition, Spinocerebellar Ataxia Type 3 (SCA3) or Machado-Joseph Disease (MJD), is characterized by cerebellar ataxia, Parkinsonism, and degeneration of motor neuron synapses. While the polyQ repeat mutant protein ataxin-3 is implicated in MJD, it is unclear how it leads to impaired synaptic function. In this study, we indicated that a Drosophila model of MJD recapitulates characteristics of neurodegenerative disorders marked by motor neuron dysfunction. Expression of 78 polyQ repeats of mutant ataxin-3 protein in Drosophila motor neurons resulted in behavioral defects, such as impaired locomotion in both larval and adult stages. Furthermore, defects in eclosion and lifespan were observed in adult flies. Detailed characterization of larval glutamatergic neuromuscular junctions (NMJs) revealed defects in morphological features along with compromised NMJ functioning. Autophagy, one of the key proteostasis pathways, is known to be impaired in the case of several synaptopathies. Our study reveals that overexpression of the autophagy-related protein Atg8a rescued behavioral defects. Thus, we present a model for glutamatergic synapse dysfunction that recapitulates synaptic and behavioral deficits and show that it is an amenable system for carrying out genetic and chemical biology screens to identify potential therapeutic targets for synaptopathies.
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Affiliation(s)
- Anushka Chakravorty
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Ankit Sharma
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
| | - Vasu Sheeba
- Chronobiology and Behavioural Neurogenetics Laboratory, Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- *Correspondence: Vasu Sheeba
| | - Ravi Manjithaya
- Autophagy Laboratory, Molecular Biology and Genetics Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- Neuroscience Unit, Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore, India
- Ravi Manjithaya
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12
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Bermedo-García F, Zelada D, Martínez E, Tabares L, Henríquez JP. Functional regeneration of the murine neuromuscular synapse relies on long-lasting morphological adaptations. BMC Biol 2022; 20:158. [PMID: 35804361 PMCID: PMC9270767 DOI: 10.1186/s12915-022-01358-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 05/05/2022] [Indexed: 12/04/2022] Open
Abstract
Background In a broad variety of species, muscle contraction is controlled at the neuromuscular junction (NMJ), the peripheral synapse composed of a motor nerve terminal, a muscle specialization, and non-myelinating terminal Schwann cells. While peripheral nerve damage leads to successful NMJ reinnervation in animal models, muscle fiber reinnervation in human patients is largely inefficient. Interestingly, some hallmarks of NMJ denervation and early reinnervation in murine species, such as fragmentation and poly-innervation, are also phenotypes of aged NMJs or even of unaltered conditions in other species, including humans. We have reasoned that rather than features of NMJ decline, such cellular responses could represent synaptic adaptations to accomplish proper functional recovery. Here, we have experimentally tackled this idea through a detailed comparative study of the short- and long-term consequences of irreversible (chronic) and reversible (partial) NMJ denervation in the convenient cranial levator auris longus muscle. Results Our findings reveal that irreversible muscle denervation results in highly fragmented postsynaptic domains and marked ectopic acetylcholine receptor clustering along with significant terminal Schwann cells sprouting and progressive detachment from the NMJ. Remarkably, even though reversible nerve damage led to complete reinnervation after 11 days, we found that more than 30% of NMJs are poly-innervated and around 65% of postsynaptic domains are fragmented even 3 months after injury, whereas synaptic transmission is fully recovered two months after nerve injury. While postsynaptic stability was irreversibly decreased after chronic denervation, this parameter was only transiently affected by partial NMJ denervation. In addition, we found that a combination of morphometric analyses and postsynaptic stability determinations allows discriminating two distinct forms of NMJ fragmentation, stable-smooth and unstable-blurred, which correlate with their regeneration potential. Conclusions Together, our data unveil that reversible nerve damage imprints a long-lasting reminiscence in the NMJ that results in the rearrangement of its cellular components. Instead of being predictive of NMJ decline, these traits may represent an efficient adaptive response for proper functional recovery. As such, these features are relevant targets to be considered in strategies aimed to restore motor function in detrimental conditions for peripheral innervation. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-022-01358-4.
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Affiliation(s)
- Francisca Bermedo-García
- Laboratory of Neuromuscular Studies (NeSt Lab), Group for the Study of Developmental Processes (GDeP), Department of Cell Biology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Diego Zelada
- Laboratory of Neuromuscular Studies (NeSt Lab), Group for the Study of Developmental Processes (GDeP), Department of Cell Biology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Esperanza Martínez
- Laboratory of Neuromuscular Studies (NeSt Lab), Group for the Study of Developmental Processes (GDeP), Department of Cell Biology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile
| | - Lucía Tabares
- Department of Medical Physiology and Biophysics, School of Medicine, Universidad de Sevilla, Sevilla, Spain
| | - Juan Pablo Henríquez
- Laboratory of Neuromuscular Studies (NeSt Lab), Group for the Study of Developmental Processes (GDeP), Department of Cell Biology, Faculty of Biological Sciences, Universidad de Concepción, Concepción, Chile.
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13
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Mhandire DZ, Burns DP, Roger AL, O'Halloran KD, ElMallah MK. Breathing in Duchenne muscular dystrophy: Translation to therapy. J Physiol 2022; 600:3465-3482. [PMID: 35620971 PMCID: PMC9357048 DOI: 10.1113/jp281671] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/17/2022] [Indexed: 11/08/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is an X-linked neuromuscular disease caused by a deficiency in dystrophin - a structural protein which stabilizes muscle during contraction. Dystrophin deficiency adversely affects the respiratory system leading to sleep-disordered breathing, hypoventilation, and weakness of the expiratory and inspiratory musculature, which culminate in severe respiratory dysfunction. Muscle degeneration associated respiratory impairment in neuromuscular disease is a result of disruptions at multiple sites of the respiratory control network, including sensory and motor pathways. As a result of this pathology, respiratory failure is a leading cause of premature death in DMD patients. Currently available treatments for DMD respiratory insufficiency attenuate respiratory symptoms without completely reversing the underlying pathophysiology. This underscores the need to develop curative therapies to improve quality of life and longevity of DMD patients. This review summarises research findings on the pathophysiology of respiratory insufficiencies in DMD disease in humans and animal models, the clinical interventions available to ameliorate symptoms, and gene-based therapeutic strategies uncovered by preclinical animal studies. Abstract figure legend: Summary of the therapeutic strategies for respiratory insufficiency in DMD (Duchenne muscular dystrophy). Treatment options currently in clinical use only attenuate respiratory symptoms without reversing the underlying pathology of DMD-associated respiratory insufficiencies. Ongoing preclinical and clinical research is aimed at developing curative therapies that both improve quality of life and longevity of DMD patients. AAV - adeno-associated virus, PPMO - Peptide-conjugated phosphorodiamidate morpholino oligomer This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Doreen Z Mhandire
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - David P Burns
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Angela L Roger
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Ken D O'Halloran
- Department of Physiology, School of Medicine, College of Medicine & Health, University College Cork, Cork, Ireland
| | - Mai K ElMallah
- Division of Pulmonary and Sleep Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
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14
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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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15
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Midena E, Cosmo E, Cattelan AM, Briani C, Leoni D, Capizzi A, Tabacchi V, Parrozzani R, Midena G, Frizziero L. Small Fibre Peripheral Alterations Following COVID-19 Detected by Corneal Confocal Microscopy. J Pers Med 2022; 12:jpm12040563. [PMID: 35455679 PMCID: PMC9030195 DOI: 10.3390/jpm12040563] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 03/30/2022] [Accepted: 03/31/2022] [Indexed: 12/07/2022] Open
Abstract
A large spectrum of neurological manifestations has been associated with coronavirus disease 2019 (COVID-19), and recently, the involvement of small fibers has been suggested. This study aims to investigate the involvement of small peripheral nervous fibers in recovered COVID-19 patients using in-vivo corneal confocal microscopy (CCM). Patients recovered from COVID-19 and a control group of healthy subjects underwent in-vivo CCM. Corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), corneal nerve fiber total branch density (CTBD), corneal nerve fiber area (CNFA), corneal nerve fiber width (CNFW), fiber tortuosity (FT), number of beadings (NBe), and dendritic cells (DC) density were quantified. We enrolled 302 eyes of 151 patients. CNBD and FT were significantly higher (p = 0.0131, p < 0.0001), whereas CNFW and NBe were significantly lower (p = 0.0056, p = 0.0045) in the COVID-19 group compared to controls. Only CNBD and FT resulted significantly correlated to antiviral drugs (increased) and corticosteroids (decreased). No significant relationship with disease severity parameters was found. COVID-19 may induce peripheral neuropathy in small fibers even months after recovery, regardless of systemic conditions and therapy, and CCM may be a useful tool to identify and monitor these morphological changes.
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Affiliation(s)
- Edoardo Midena
- Ophthalmology Unit, Department of Neuroscience, University of Padova, 35128 Padova, Italy; (V.T.); (R.P.); (L.F.)
- IRCCS—Fondazione Bietti, 00198 Rome, Italy; (E.C.); (G.M.)
- Correspondence: ; Tel.: +39-049-821-2110
| | - Eleonora Cosmo
- IRCCS—Fondazione Bietti, 00198 Rome, Italy; (E.C.); (G.M.)
| | - Anna Maria Cattelan
- Unit of Infectious Disease, Department of Internal Medicine, University of Padova, 35128 Padova, Italy; (A.M.C.); (D.L.)
| | - Chiara Briani
- Neurology Unit, Department of Neuroscience, University of Padova, 35128 Padova, Italy;
| | - Davide Leoni
- Unit of Infectious Disease, Department of Internal Medicine, University of Padova, 35128 Padova, Italy; (A.M.C.); (D.L.)
| | - Alfio Capizzi
- Department of Directional Hospital Management, University of Padova, 35128 Padova, Italy;
| | - Vanessa Tabacchi
- Ophthalmology Unit, Department of Neuroscience, University of Padova, 35128 Padova, Italy; (V.T.); (R.P.); (L.F.)
| | - Raffaele Parrozzani
- Ophthalmology Unit, Department of Neuroscience, University of Padova, 35128 Padova, Italy; (V.T.); (R.P.); (L.F.)
| | - Giulia Midena
- IRCCS—Fondazione Bietti, 00198 Rome, Italy; (E.C.); (G.M.)
| | - Luisa Frizziero
- Ophthalmology Unit, Department of Neuroscience, University of Padova, 35128 Padova, Italy; (V.T.); (R.P.); (L.F.)
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16
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Kiriaev L, Kueh S, Morley JW, North KN, Houweling PJ, Head SI. Lifespan Analysis of Dystrophic mdx Fast-Twitch Muscle Morphology and Its Impact on Contractile Function. Front Physiol 2021; 12:771499. [PMID: 34950049 PMCID: PMC8689589 DOI: 10.3389/fphys.2021.771499] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Duchenne muscular dystrophy is caused by the absence of the protein dystrophin from skeletal muscle and is characterized by progressive cycles of necrosis/regeneration. Using the dystrophin deficient mdx mouse model, we studied the morphological and contractile chronology of dystrophic skeletal muscle pathology in fast-twitch Extensor Digitorum Longus muscles from animals 4–22 months of age containing 100% regenerated muscle fibers. Catastrophically, the older age groups lost ∼80% of their maximum force after one eccentric contraction (EC) of 20% strain with the greatest loss of ∼92% recorded in senescent 22-month-old mdx mice. In old age groups, there was minimal force recovery ∼24% after 120 min, correlated with a dramatic increase in the number and complexity of branched fibers. This data supports our two-phase model where a “tipping point” is reached when branched fibers rupture irrevocably on EC. These findings have important implications for pre-clinical drug studies and genetic rescue strategies.
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Affiliation(s)
- Leonit Kiriaev
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
- *Correspondence: Leonit Kiriaev,
| | - Sindy Kueh
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - John W. Morley
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Kathryn N. North
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
| | - Peter J. Houweling
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
| | - Stewart I. Head
- Myogenica Laboratory, School of Medicine, Western Sydney University, Sydney, NSW, Australia
- Muscle Research Group, Murdoch Children’s Research Institute, Melbourne, VIC, Australia
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17
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Fralish Z, Lotz EM, Chavez T, Khodabukus A, Bursac N. Neuromuscular Development and Disease: Learning From in vitro and in vivo Models. Front Cell Dev Biol 2021; 9:764732. [PMID: 34778273 PMCID: PMC8579029 DOI: 10.3389/fcell.2021.764732] [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: 08/25/2021] [Accepted: 10/06/2021] [Indexed: 01/02/2023] Open
Abstract
The neuromuscular junction (NMJ) is a specialized cholinergic synaptic interface between a motor neuron and a skeletal muscle fiber that translates presynaptic electrical impulses into motor function. NMJ formation and maintenance require tightly regulated signaling and cellular communication among motor neurons, myogenic cells, and Schwann cells. Neuromuscular diseases (NMDs) can result in loss of NMJ function and motor input leading to paralysis or even death. Although small animal models have been instrumental in advancing our understanding of the NMJ structure and function, the complexities of studying this multi-tissue system in vivo and poor clinical outcomes of candidate therapies developed in small animal models has driven the need for in vitro models of functional human NMJ to complement animal studies. In this review, we discuss prevailing models of NMDs and highlight the current progress and ongoing challenges in developing human iPSC-derived (hiPSC) 3D cell culture models of functional NMJs. We first review in vivo development of motor neurons, skeletal muscle, Schwann cells, and the NMJ alongside current methods for directing the differentiation of relevant cell types from hiPSCs. We further compare the efficacy of modeling NMDs in animals and human cell culture systems in the context of five NMDs: amyotrophic lateral sclerosis, myasthenia gravis, Duchenne muscular dystrophy, myotonic dystrophy, and Pompe disease. Finally, we discuss further work necessary for hiPSC-derived NMJ models to function as effective personalized NMD platforms.
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Affiliation(s)
- Zachary Fralish
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States
| | - Ethan M Lotz
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States
| | - Taylor Chavez
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States
| | - Alastair Khodabukus
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States
| | - Nenad Bursac
- Department of Biomedical Engineering, Pratt School of Engineering, Duke University, Durham, NC, United States
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18
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Kiriaev L, Houweling PJ, North KN, Head SI. Loss of α-actinin-3 confers protection from eccentric contraction damage in fast-twitch EDL muscles from aged mdx dystrophic mice by reducing pathological fibre branching. Hum Mol Genet 2021; 31:1417-1429. [PMID: 34761268 PMCID: PMC9071495 DOI: 10.1093/hmg/ddab326] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/27/2021] [Accepted: 11/02/2021] [Indexed: 11/14/2022] Open
Abstract
The common null polymorphism (R577X) in the ACTN3 gene is present in over 1.5 billion people worldwide and results in the absence of the protein α-actinin-3 from the Z-discs of fast-twitch skeletal muscle fibres. We have previously reported that this polymorphism is a modifier of dystrophin deficient Duchenne Muscular Dystrophy. To investigate the mechanism underlying this we use a double knockout (dk)Actn3KO/mdx (dKO) mouse model which lacks both dystrophin and sarcomere α-actinin-3. We used dKO mice and mdx dystrophic mice at 12 months (aged) to investigate the correlation between morphological changes to the fast-twitch dKO EDL and the reduction in force deficit produced by an in vitro eccentric contraction protocol. In the aged dKO mouse we found a marked reduction in fibre branching complexity that correlated with protection from eccentric contraction induced force deficit. Complex branches in the aged dKO EDL fibres (28%) were substantially reduced compared to aged mdx EDL fibres (68%) and this correlates with a graded force loss over three eccentric contractions for dKO muscles (~35% after first contraction, ~ 66% overall) compared to an abrupt drop in mdx upon the first eccentric contraction (~73% after first contraction, ~ 89% after three contractions). In dKO protection from eccentric contraction damage was linked with a doubling of SERCA1 pump density the EDL. We propose that the increased oxidative metabolism of fast-twitch glycolytic fibres characteristic of the null polymorphism (R577X) and increase in SR Ca2+ pump proteins reduces muscle fibre branching and decreases susceptibility to eccentric injury in the dystrophinopathies.
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Affiliation(s)
- Leonit Kiriaev
- School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Peter J Houweling
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Kathryn N North
- Murdoch Children's Research Institute, Melbourne, Victoria, Australia.,Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia
| | - Stewart I Head
- School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Murdoch Children's Research Institute, Melbourne, Victoria, Australia
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19
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Yu M, Gu G, Cong M, Du M, Wang W, Shen M, Zhang Q, Shi H, Gu X, Ding F. Repair of peripheral nerve defects by nerve grafts incorporated with extracellular vesicles from skin-derived precursor Schwann cells. Acta Biomater 2021; 134:190-203. [PMID: 34289422 DOI: 10.1016/j.actbio.2021.07.026] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/12/2021] [Accepted: 07/13/2021] [Indexed: 12/16/2022]
Abstract
Our previous studies have shown that extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs) promote neurite outgrowth of sensory and motor neurons in vitro. This study was aimed at generating an artificial nerve graft incorporated with SKP-SC-EVs to examine in vivo effects of SKP-SC-EVs on peripheral nerve regeneration. Here SKP-SC-EVs were isolated and then identified by morphological observation and phenotypic marker expression. Following co-culture with SCs or motoneurons, SKP-SC-EVs were internalized, showing the capability to enhance SC viability or motoneuron neurite outgrowth. In vitro, SKP-SC-EVs released from Matrigel could maintain cellular uptake property and neural activity. Nerve grafts were developed by incorporating Matrigel-encapsulated SKP-SC-EVs into silicone conduits. Functional evaluation, histological investigation, and morphometric analysis were performed to compare the nerve regenerative outcome after bridging the 10-mm long sciatic nerve defect in rats with our developed nerve grafts, silicone conduits (filled with vehicle), and autografts respectively. Our developed nerve grafts significantly accelerated the recovery of motor, sensory, and electrophysiological functions of rats, facilitated outgrowth and myelination of regenerated axons, and alleviated denervation-induced atrophy of target muscles. Collectively, our findings suggested that incorporation of SKP-SC-EVs into nerve grafts might represent a promising paradigm for peripheral nerve injury repair. STATEMENT OF SIGNIFICANCE: Nerve grafts have been progressively developed to meet the increasing requirements for peripheral nerve injury repair. Here we reported a design of nerve grafts featured by incorporation of Matrigel-encapsulated extracellular vesicles from skin-derived precursor Schwann cells (SKP-SC-EVs), because SKP-SC-EVs were found to possess in vitro neural activity, thus raising the possibility of cell-free therapy. Our developed nerve grafts yielded the satisfactory outcome of nerve grafting in rats with a 10-mm long sciatic nerve defect, as evaluated by functional and morphological assessments. The promoting effects of SKP-SC-EVs-incorporating nerve grafts on peripheral nerve regeneration might benefit from in vivo biological cues afforded by SKP-SC-EVs, which had been released from Matrigel and then internalized by residual neural cells in sciatic nerve stumps.
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Affiliation(s)
- Miaomei Yu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China; Clinical Medical Research Center, The Third Affiliated Hospital of Soochow University, Changzhou, China
| | - Guohao Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Meng Cong
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Mingzhi Du
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Wei Wang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Mi Shen
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Qi Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Haiyan Shi
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China; Department of Pathophysiology, School of Medicine, Nantong University, Nantong, China
| | - Xiaosong Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China; Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Affiliated Hospital of Nantong University, Nantong, China
| | - Fei Ding
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education and Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China; Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Affiliated Hospital of Nantong University, Nantong, China.
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20
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Li J, Fredericks M, Cannell M, Wang K, Sako D, Maguire MC, Grenha R, Liharska K, Krishnan L, Bloom T, Belcheva EP, Martinez PA, Castonguay R, Keates S, Alexander MJ, Choi H, Grinberg AV, Pearsall RS, Oh P, Kumar R, Suragani RN. ActRIIB:ALK4-Fc alleviates muscle dysfunction and comorbidities in murine models of neuromuscular disorders. J Clin Invest 2021; 131:138634. [PMID: 33586684 DOI: 10.1172/jci138634] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 12/29/2020] [Indexed: 01/06/2023] Open
Abstract
Patients with neuromuscular disorders suffer from a lack of treatment options for skeletal muscle weakness and disease comorbidities. Here, we introduce as a potential therapeutic agent a heterodimeric ligand-trapping fusion protein, ActRIIB:ALK4-Fc, which comprises extracellular domains of activin-like kinase 4 (ALK4) and activin receptor type IIB (ActRIIB), a naturally occurring pair of type I and II receptors belonging to the TGF-β superfamily. By surface plasmon resonance (SPR), ActRIIB:ALK4-Fc exhibited a ligand binding profile distinctly different from that of its homodimeric variant ActRIIB-Fc, sequestering ActRIIB ligands known to inhibit muscle growth but not trapping the vascular regulatory ligand bone morphogenetic protein 9 (BMP9). ActRIIB:ALK4-Fc and ActRIIB-Fc administered to mice exerted differential effects - concordant with SPR results - on vessel outgrowth in a retinal explant assay. ActRIIB:ALK4-Fc induced a systemic increase in muscle mass and function in wild-type mice and in murine models of Duchenne muscular dystrophy (DMD), amyotrophic lateral sclerosis (ALS), and disuse atrophy. Importantly, ActRIIB:ALK4-Fc improved neuromuscular junction abnormalities in murine models of DMD and presymptomatic ALS and alleviated acute muscle fibrosis in a DMD model. Furthermore, in combination therapy ActRIIB:ALK4-Fc increased the efficacy of antisense oligonucleotide M12-PMO on dystrophin expression and skeletal muscle endurance in an aged DMD model. ActRIIB:ALK4-Fc shows promise as a therapeutic agent, alone or in combination with dystrophin rescue therapy, to alleviate muscle weakness and comorbidities of neuromuscular disorders.
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Affiliation(s)
- Jia Li
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | - Kathryn Wang
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | - Dianne Sako
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | - Rosa Grenha
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | - Troy Bloom
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | | | - Sarah Keates
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | - Hyunwoo Choi
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona, USA
| | | | | | - Paul Oh
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona, USA
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21
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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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22
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NMJ-Analyser identifies subtle early changes in mouse models of neuromuscular disease. Sci Rep 2021; 11:12251. [PMID: 34112844 PMCID: PMC8192785 DOI: 10.1038/s41598-021-91094-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 04/26/2021] [Indexed: 12/21/2022] Open
Abstract
The neuromuscular junction (NMJ) is the peripheral synapse formed between a motor neuron axon terminal and a muscle fibre. NMJs are thought to be the primary site of peripheral pathology in many neuromuscular diseases, but innervation/denervation status is often assessed qualitatively with poor systematic criteria across studies, and separately from 3D morphological structure. Here, we describe the development of ‘NMJ-Analyser’, to comprehensively screen the morphology of NMJs and their corresponding innervation status automatically. NMJ-Analyser generates 29 biologically relevant features to quantitatively define healthy and aberrant neuromuscular synapses and applies machine learning to diagnose NMJ degeneration. We validated this framework in longitudinal analyses of wildtype mice, as well as in four different neuromuscular disease models: three for amyotrophic lateral sclerosis (ALS) and one for peripheral neuropathy. We showed that structural changes at the NMJ initially occur in the nerve terminal of mutant TDP43 and FUS ALS models. Using a machine learning algorithm, healthy and aberrant neuromuscular synapses are identified with 95% accuracy, with 88% sensitivity and 97% specificity. Our results validate NMJ-Analyser as a robust platform for systematic and structural screening of NMJs, and pave the way for transferrable, and cross-comparison and high-throughput studies in neuromuscular diseases.
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23
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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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24
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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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25
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Sorensen JR, Hoffman DB, Corona BT, Greising SM. Secondary denervation is a chronic pathophysiologic sequela of volumetric muscle loss. J Appl Physiol (1985) 2021; 130:1614-1625. [PMID: 33830817 DOI: 10.1152/japplphysiol.00049.2021] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Volumetric muscle loss (VML) is the traumatic loss of muscle tissue that results in long-term functional impairments. Despite the loss of myofibers, there remains an unexplained significant decline in muscle function. VML injury likely extends beyond the defect area, causing negative secondary outcomes to the neuromuscular system, including the neuromuscular junctions (NMJs), yet the extent to which VML induces denervation is unclear. This study systematically examined NMJs surrounding the VML injury, hypothesizing that the sequela of VML includes denervation. The VML injury removed ∼20% of the tibialis anterior (TA) muscle in adult male inbred Lewis rats (n = 43), the noninjured leg served as an intra-animal control. Muscles were harvested up to 48 days post-VML. Synaptic terminals were identified immunohistochemically, and quantitative confocal microscopy evaluated 2,613 individual NMJ. Significant denervation was apparent by 21 and 48 days post-VML. Initially, denervation increased ∼10% within 3 days of injury; with time, denervation further increased to ∼22% and 32% by 21 and 48 days post-VML, respectively, suggesting significant secondary denervation. The appearance of terminal axon sprouting and polyinnervation were observed as early as 7 days post-VML, increasing in number and complexity throughout 48 days. There was no evidence of VML-induced NMJ size alteration, which may be beneficial for interventions aimed at restoring muscle function. This work recognizes VML-induced secondary denervation and poor remodeling of the NMJ as part of the sequela of VML injury; moreover, secondary denervation is a possible contributing factor to the chronic functional impairments and potentially an overlooked treatment target.NEW & NOTEWORTHY This work advances our understanding of the pathophysiologic complexity of volumetric muscle loss injury. Specifically, we identified secondary denervation in the muscle remaining after volumetric muscle loss injuries as a novel aspect of the injury sequela. Denervation increased chronically, in parallel with the appearance of irregular morphological characteristics and destabilization of the neuromuscular junction, which is expected to further confound chronic functional impairments.
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Affiliation(s)
- Jacob R Sorensen
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota
| | - Daniel B Hoffman
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota
| | - Benjamin T Corona
- School of Medicine, Wake Forest University, Winston-Salem, North Carolina
| | - Sarah M Greising
- School of Kinesiology, University of Minnesota, Minneapolis, Minnesota
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26
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Park S, Park JH, Kang UB, Choi SK, Elfadl A, Ullah HMA, Chung MJ, Son JY, Yun HH, Park JM, Yim JH, Jung SJ, Kim SH, Choi YC, Kim DS, Shin JH, Park JS, Hur K, Lee SH, Lee EJ, Hwang D, Jeong KS. Nogo-A regulates myogenesis via interacting with Filamin-C. Cell Death Discov 2021; 7:1. [PMID: 33414425 PMCID: PMC7791112 DOI: 10.1038/s41420-020-00384-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 11/22/2020] [Accepted: 11/28/2020] [Indexed: 12/23/2022] Open
Abstract
Among the three isoforms encoded by Rtn4, Nogo-A has been intensely investigated as a central nervous system inhibitor. Although Nogo-A expression is increased in muscles of patients with amyotrophic lateral sclerosis, its role in muscle homeostasis and regeneration is not well elucidated. In this study, we discovered a significant increase in Nogo-A expression in various muscle-related pathological conditions. Nogo−/− mice displayed dystrophic muscle structure, dysregulated muscle regeneration following injury, and altered gene expression involving lipid storage and muscle cell differentiation. We hypothesized that increased Nogo-A levels might regulate muscle regeneration. Differentiating myoblasts exhibited Nogo-A upregulation and silencing Nogo-A abrogated myoblast differentiation. Nogo-A interacted with filamin-C, suggesting a role for Nogo-A in cytoskeletal arrangement during myogenesis. In conclusion, Nogo-A maintains muscle homeostasis and integrity, and pathologically altered Nogo-A expression mediates muscle regeneration, suggesting Nogo-A as a novel target for the treatment of myopathies in clinical settings.
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Affiliation(s)
- SunYoung Park
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea.,Stem Cell Therapeutic Research Institute, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Ji-Hwan Park
- Department of New Biology, DGIST, Daegu, 42988, Republic of Korea
| | - Un-Beom Kang
- R&D Division, BERTIS, Inc., Seongnam-si, Gyeonggi-do, 13605, Republic of Korea
| | - Seong-Kyoon Choi
- Division of Biotechnology, DGIST, Daegu, 42988, Republic of Korea.,Core Protein Resources Center, DGIST, Daegu, 42988, Republic of Korea
| | - Ahmed Elfadl
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - H M Arif Ullah
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Myung-Jin Chung
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Ji-Yoon Son
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Hyun Ho Yun
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Jae-Min Park
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Jae-Hyuk Yim
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Seung-Jun Jung
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Sang-Hyup Kim
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Young-Chul Choi
- Department of Neurology, Gangnam Severance Hospital, Yonsei University College of Medicine, Seoul, 06058, Republic of Korea
| | - Dae-Seong Kim
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, 50612, Republic of Korea
| | - Jin-Hong Shin
- Department of Neurology, Pusan National University Yangsan Hospital, Yangsan, 50612, Republic of Korea
| | - Jin-Sung Park
- Department of Neurology, Kyungpook National University School of Medicine, Daegu, 41944, Republic of Korea
| | - Keun Hur
- Department of Biochemistry and Cell Biology, Kyungpook National University School of Medicine, Daegu, 41944, Republic of Korea
| | - Sang-Han Lee
- Department of Food Science and Biotechnology, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Eun-Joo Lee
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea
| | - Daehee Hwang
- Department of Biological Sciences, Seoul National University, Seoul, 08826, Republic of Korea
| | - Kyu-Shik Jeong
- Department of Pathology, College of Veterinary Medicine, Kyungpook National University, Daegu, 41566, Republic of Korea. .,Stem Cell Therapeutic Research Institute, Kyungpook National University, Daegu, 41566, Republic of Korea.
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27
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Fang C, Yu T, Chu T, Feng W, Zhao F, Wang X, Huang Y, Li Y, Wan P, Mei W, Zhu D, Fei P. Minutes-timescale 3D isotropic imaging of entire organs at subcellular resolution by content-aware compressed-sensing light-sheet microscopy. Nat Commun 2021; 12:107. [PMID: 33398061 PMCID: PMC7782498 DOI: 10.1038/s41467-020-20329-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 11/20/2020] [Indexed: 01/29/2023] Open
Abstract
Rapid 3D imaging of entire organs and organisms at cellular resolution is a recurring challenge in life science. Here we report on a computational light-sheet microscopy able to achieve minute-timescale high-resolution mapping of entire macro-scale organs. Through combining a dual-side confocally-scanned Bessel light-sheet illumination which provides thinner-and-wider optical sectioning of deep tissues, with a content-aware compressed sensing (CACS) computation pipeline which further improves the contrast and resolution based on a single acquisition, our approach yields 3D images with high, isotropic spatial resolution and rapid acquisition over two-order-of-magnitude faster than conventional 3D microscopy implementations. We demonstrate the imaging of whole brain (~400 mm3), entire gastrocnemius and tibialis muscles (~200 mm3) of mouse at ultra-high throughput of 5~10 min per sample and post-improved subcellular resolution of ~ 1.5 μm (0.5-μm iso-voxel size). Various system-level cellular analyses, such as mapping cell populations at different brain sub-regions, tracing long-distance projection neurons over the entire brain, and calculating neuromuscular junction occupancy across whole muscle, are also readily accomplished by our method.
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Affiliation(s)
- Chunyu Fang
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Tingting Yu
- Britton Chance center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
- MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Tingting Chu
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Wenyang Feng
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Fang Zhao
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Xuechun Wang
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Yujie Huang
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, China
| | - Yusha Li
- Britton Chance center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Peng Wan
- Britton Chance center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China
| | - Wei Mei
- Department of Anesthesiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, China.
| | - Dan Zhu
- Britton Chance center for Biomedical Photonics, Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China.
- MoE Key Laboratory for Biomedical Photonics, Huazhong University of Science and Technology, 430074, Wuhan, China.
| | - Peng Fei
- School of Optical and Electronic Information- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, 430074, Wuhan, China.
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Taetzsch T, Shapiro D, Eldosougi R, Myers T, Settlage RE, Valdez G. The microRNA miR-133b functions to slow Duchenne muscular dystrophy pathogenesis. J Physiol 2021; 599:171-192. [PMID: 32991751 PMCID: PMC8418193 DOI: 10.1113/jp280405] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 09/14/2020] [Indexed: 01/22/2023] Open
Abstract
KEY POINTS Impairment of muscle biogenesis contributes to the progression of Duchenne muscular dystrophy (DMD). As a muscle enriched microRNA that has been implicated in muscle biogenesis, the role of miR-133b in DMD remains unknown. To assess miR-133b function in DMD-affected skeletal muscles, we genetically ablated miR-133b in the mdx mouse model of DMD. We show that deletion of miR-133b exacerbates the dystrophic phenotype of DMD-afflicted skeletal muscle by dysregulating muscle stem cells involved in muscle biogenesis, in addition to affecting signalling pathways related to inflammation and fibrosis. Our results provide evidence that miR-133b may underlie DMD pathology by affecting the proliferation and differentiation of muscle stem cells. ABSTRACT Duchenne muscular dystrophy (DMD) is characterized by progressive skeletal muscle degeneration. No treatments are currently available to prevent the disease. While the muscle enriched microRNA miR-133b has been implicated in muscle biogenesis, its role in DMD remains unknown. To assess miR-133b function in DMD-affected skeletal muscles, we genetically ablated miR-133b in the mdx mouse model of DMD. In the absence of miR-133b, the tibialis anterior muscle of P30 mdx mice is smaller in size and exhibits a thickened interstitial space containing more mononucleated cells. Additional analysis revealed that miR-133b deletion influences muscle fibre regeneration, satellite cell proliferation and differentiation, and induces widespread transcriptomic changes in mdx muscle. These include known miR-133b targets as well as genes involved in cell proliferation and fibrosis. Altogether, our data demonstrate that skeletal muscles utilize miR-133b to mitigate the deleterious effects of DMD.
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Affiliation(s)
- Thomas Taetzsch
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Dillon Shapiro
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, RI, USA
| | - Randa Eldosougi
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | - Tracey Myers
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA, USA
| | | | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, United States
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, United States
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Zelada D, Bermedo-García F, Collao N, Henríquez JP. Motor function recovery: deciphering a regenerative niche at the neuromuscular synapse. Biol Rev Camb Philos Soc 2020; 96:752-766. [PMID: 33336525 PMCID: PMC7986695 DOI: 10.1111/brv.12675] [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: 04/28/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022]
Abstract
The coordinated movement of many organisms relies on efficient nerve–muscle communication at the neuromuscular junction (NMJ), a peripheral synapse composed of a presynaptic motor axon terminal, a postsynaptic muscle specialization, and non‐myelinating terminal Schwann cells. NMJ dysfunctions are caused by traumatic spinal cord or peripheral nerve injuries as well as by severe motor pathologies. Compared to the central nervous system, the peripheral nervous system displays remarkable regenerating abilities; however, this capacity is limited by the denervation time frame and depends on the establishment of permissive regenerative niches. At the injury site, detailed information is available regarding the cells, molecules, and mechanisms involved in nerve regeneration and repair. However, a regenerative niche at the final functional step of peripheral motor innervation, i.e. at the mature neuromuscular synapse, has not been deciphered. In this review, we integrate classic and recent evidence describing the cells and molecules that could orchestrate a dynamic ecosystem to accomplish successful NMJ regeneration. We propose that such a regenerative niche must ensure at least two fundamental steps for successful NMJ regeneration: the proper arrival of incoming regenerating axons to denervated postsynaptic muscle domains, and the resilience of those postsynaptic domains, in morphological and functional terms. We here describe and combine the main cellular and molecular responses involved in each of these steps as potential targets to help successful NMJ regeneration.
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Affiliation(s)
- Diego Zelada
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Francisca Bermedo-García
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Nicolás Collao
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Juan P Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
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Kim M, Franke V, Brandt B, Lowenstein ED, Schöwel V, Spuler S, Akalin A, Birchmeier C. Single-nucleus transcriptomics reveals functional compartmentalization in syncytial skeletal muscle cells. Nat Commun 2020; 11:6375. [PMID: 33311457 PMCID: PMC7732842 DOI: 10.1038/s41467-020-20064-9] [Citation(s) in RCA: 90] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/09/2020] [Indexed: 11/25/2022] Open
Abstract
Syncytial skeletal muscle cells contain hundreds of nuclei in a shared cytoplasm. We investigated nuclear heterogeneity and transcriptional dynamics in the uninjured and regenerating muscle using single-nucleus RNA-sequencing (snRNAseq) of isolated nuclei from muscle fibers. This revealed distinct nuclear subtypes unrelated to fiber type diversity, previously unknown subtypes as well as the expected ones at the neuromuscular and myotendinous junctions. In fibers of the Mdx dystrophy mouse model, distinct subtypes emerged, among them nuclei expressing a repair signature that were also abundant in the muscle of dystrophy patients, and a nuclear population associated with necrotic fibers. Finally, modifications of our approach revealed the compartmentalization in the rare and specialized muscle spindle. Our data identifies nuclear compartments of the myofiber and defines a molecular roadmap for their functional analyses; the data can be freely explored on the MyoExplorer server ( https://shiny.mdc-berlin.de/MyoExplorer/ ).
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Affiliation(s)
- Minchul Kim
- Developmental Biology/Signal Transduction, Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Vedran Franke
- Berlin Institute for Medical Systems Biology, Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Bettina Brandt
- Developmental Biology/Signal Transduction, Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Elijah D Lowenstein
- Developmental Biology/Signal Transduction, Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Verena Schöwel
- Muscle Research Unit, Experimental and Clinical Research Center, Charité Universitätsmedizin Berlin and Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Simone Spuler
- Muscle Research Unit, Experimental and Clinical Research Center, Charité Universitätsmedizin Berlin and Max Delbrueck Center for Molecular Medicine, Berlin, Germany
| | - Altuna Akalin
- Berlin Institute for Medical Systems Biology, Max Delbrueck Center for Molecular Medicine, Berlin, Germany.
| | - Carmen Birchmeier
- Developmental Biology/Signal Transduction, Max Delbrueck Center for Molecular Medicine, Berlin, Germany.
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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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Lifetime analysis of mdx skeletal muscle reveals a progressive pathology that leads to myofiber loss. Sci Rep 2020; 10:17248. [PMID: 33057110 PMCID: PMC7560899 DOI: 10.1038/s41598-020-74192-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 09/23/2020] [Indexed: 02/06/2023] Open
Abstract
The muscular dystrophy X-linked mouse (mdx) is the most commonly used preclinical model for Duchenne muscular dystrophy. Although disease progression in the mouse does not perfectly model the human disease, it shares many pathological features. Early characterizations of the model reported severe pathology through early adulthood followed by disease stabilization. As a result, research in the mdx mouse has largely focused on early adulthood. The overarching goal of this study is to improve the understanding of the mdx mouse model by tracking pathological features of the disease throughout life. We performed a thorough characterization of myofiber pathology in mdx mice from 2 weeks to 2 years of age. We report that individual mdx muscle fibers undergo progressive hypertrophy that continues through the lifespan. Despite massive hypertrophy on the myofiber level, we report no hypertrophy on the muscle level. These seemingly contradictory findings are explained by previously underappreciated myofiber loss in mdx mice. We conclude that due to myofiber loss, in combination with the progressive nature of other pathological features, aged mdx muscle tissue provides reliable benchmarks for disease progression that may be valuable in testing the efficacy of therapeutics for Duchenne muscular dystrophy.
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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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Krishnan VS, Thanigaiarasu LP, White R, Crew R, Larcher T, Le Guiner C, Grounds MD. Dystrophic Dmd mdx rats show early neuronal changes (increased S100β and Tau5) at 8 months, supporting severe dystropathology in this rodent model of Duchenne muscular dystrophy. Mol Cell Neurosci 2020; 108:103549. [PMID: 32890728 DOI: 10.1016/j.mcn.2020.103549] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 08/27/2020] [Accepted: 08/28/2020] [Indexed: 12/25/2022] Open
Abstract
The intrinsic necrosis of skeletal muscles in animal models of Duchenne muscular dystrophy (DMD) damages neuromuscular junctions (NMJs) with progressively altered NMJs associated with denervation and premature changes in dystrophic nerves. In the mdx mouse model of DMD, the proteins S100β and Tau5 are significantly increased in sciatic nerves by 13 months (M) of age, far earlier (by 9 M) than in normal wildtype (WT) nerves. Since dystrophic Dmdmdx rats are reported to have a more severe dystropathology than mdx mice, we hypothesised that Dmdmdx rat nerves would show earlier neuronal changes compared with mdx nerves. We quantified levels of 8 proteins (by immunoblotting) in sciatic and radial nerves from young adult Dmdmdx rats (aged 8 M) and mdx mice (9 M), plus levels of 7 mRNAs (by qPCR) in rat nerves only. Sciatic nerves of 8 M Dmdmdx rats had more consistently increased levels of S100β and Tau5 proteins, compared with 9 M mdx mice, supporting pronounced dystropathology in the rat model. There were no differences for mRNA levels, apart from higher gelsolin mRNA in Dmdmdx sciatic nerves. The pronounced protein changes in Dmdmdx nerves indicate a severe ongoing myonecrosis, and likely consequent myofibre denervation, for the dystrophic rat model. These data support increased neuronal proteins in dystrophic nerves as a novel pre-clinical readout of ongoing myonecrosis for DMD research. In older DMD boys, such progressive neuronal changes over many years are likely to contribute to loss of muscle function, and may complicate evaluation of late-onset clinical therapies.
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Affiliation(s)
- Vidya S Krishnan
- School of Human Sciences, the University of Western Australia, Australia, 6009
| | | | - Robert White
- School of Human Sciences, the University of Western Australia, Australia, 6009
| | - Rachael Crew
- School of Human Sciences, the University of Western Australia, Australia, 6009
| | | | - Caroline Le Guiner
- INSERM UMR1089, University of Nantes, Translational Research for Neuromuscular Diseases, Nantes, France
| | - Miranda D Grounds
- School of Human Sciences, the University of Western Australia, Australia, 6009.
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35
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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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36
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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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Dhindsa JS, McCall AL, Strickland LM, Fusco AF, Kahn AF, ElMallah MK. Motor axonopathies in a mouse model of Duchenne muscular dystrophy. Sci Rep 2020; 10:8967. [PMID: 32488044 PMCID: PMC7265344 DOI: 10.1038/s41598-020-65824-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 04/22/2020] [Indexed: 11/28/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is a fatal neuromuscular disease caused by deleterious mutations in the DMD gene which encodes the dystrophin protein. Skeletal muscle weakness and eventual muscle degradation due to loss of dystrophin are well-documented pathological hallmarks of DMD. In contrast, the neuropathology of this disease remains understudied despite the emerging evidence of neurological abnormalities induced by dystrophin loss. Using quantitative morphological analysis of nerve sections, we characterize axonopathies in the phrenic and hypoglossal (XII) nerves of mdx mice. We observe dysfunction in these nerves – which innervate the diaphragm and genioglossus respectively – that we propose contributes to respiratory failure, the most common cause of death in DMD. These observations highlight the importance in the further characterization of the neuropathology of DMD. Additionally, these observations underscore the necessity in correcting both the nervous system pathology in addition to skeletal muscle deficits to ameliorate this disease.
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Affiliation(s)
- Justin S Dhindsa
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Angela L McCall
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Laura M Strickland
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Anna F Fusco
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Amanda F Kahn
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA
| | - Mai K ElMallah
- Division of Allergy, Immunology, and Pulmonary Medicine, Department of Pediatrics, Duke University Medical Center Box 2644, Durham, North Carolina, 27710, USA.
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38
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Implications of increased S100β and Tau5 proteins in dystrophic nerves of two mdx mouse models for Duchenne muscular dystrophy. Mol Cell Neurosci 2020; 105:103484. [DOI: 10.1016/j.mcn.2020.103484] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 03/25/2020] [Indexed: 12/31/2022] Open
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39
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Kravtsova VV, Bouzinova EV, Chibalin AV, Matchkov VV, Krivoi II. Isoform-specific Na,K-ATPase and membrane cholesterol remodeling in motor endplates in distinct mouse models of myodystrophy. Am J Physiol Cell Physiol 2020; 318:C1030-C1041. [PMID: 32293933 DOI: 10.1152/ajpcell.00453.2019] [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] [Indexed: 12/30/2022]
Abstract
Na,K-ATPase is a membrane transporter that is critically important for skeletal muscle function. Mdx and Bla/J mice are the experimental models of Duchenne muscular dystrophy and dysferlinopathy that are known to differ in the molecular mechanism of the pathology. This study examines the function of α1- and α2-Na,K-ATPase isozymes in respiratory diaphragm and postural soleus muscles from mdx and Bla/J mice compared with control С57Bl/6 mice. In diaphragm muscles, the motor endplate structure was severely disturbed (manifested by defragmentation) in mdx mice only. The endplate membrane of both Bla/J and mdx mice was depolarized due to specific loss of the α2-Na,K-ATPase electrogenic activity and its decreased membrane abundance. Total FXYD1 subunit (modulates Na,K-ATPase activity) abundance was decreased in both mouse models. However, the α2-Na,K-ATPase protein content as well as mRNA expression were specifically and significantly reduced only in mdx mice. The endplate membrane cholesterol redistribution was most pronounced in mdx mice. Soleus muscles from Bla/J and mdx mice demonstrated reduction of the α2-Na,K-ATPase membrane abundance and mRNA expression similar to the diaphragm muscles. In contrast to diaphragm, the α2-Na,K-ATPase protein content was altered in both Bla/J and mdx mice; membrane cholesterol re-distribution was not observed. Thus, the α2-Na,K-ATPase is altered in both Bla/J and mdx mouse models of chronic muscle pathology. However, despite some similarities, the α2-Na,K-ATPase and cholesterol abnormalities are more pronounced in mdx mice.
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Affiliation(s)
- Violetta V Kravtsova
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
| | | | | | | | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg, Russia
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40
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N-acetylcysteine Decreases Fibrosis and Increases Force-Generating Capacity of mdx Diaphragm. Antioxidants (Basel) 2019; 8:antiox8120581. [PMID: 31771272 PMCID: PMC6943616 DOI: 10.3390/antiox8120581] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 11/10/2019] [Accepted: 11/21/2019] [Indexed: 02/06/2023] Open
Abstract
Respiratory muscle weakness occurs due to dystrophin deficiency in Duchenne muscular dystrophy (DMD). The mdx mouse model of DMD shows evidence of impaired respiratory muscle performance with attendant inflammation and oxidative stress. We examined the effects of N-acetylcysteine (NAC) supplementation on respiratory system performance in mdx mice. Eight-week-old male wild type (n = 10) and mdx (n = 20) mice were studied; a subset of mdx (n = 10) received 1% NAC in the drinking water for 14 days. We assessed breathing, diaphragm, and external intercostal electromyogram (EMG) activities and inspiratory pressure during ventilatory and non-ventilatory behaviours. Diaphragm muscle structure and function, cytokine concentrations, glutathione status, and mRNA expression were determined. Diaphragm force-generating capacity was impaired in mdx compared with wild type. Diaphragm muscle remodelling was observed in mdx, characterized by increased muscle fibrosis, immune cell infiltration, and central myonucleation. NAC supplementation rescued mdx diaphragm function. Collagen content and immune cell infiltration were decreased in mdx + NAC compared with mdx diaphragms. The cytokines IL-1β, IL-6 and KC/GRO were increased in mdx plasma and diaphragm compared with wild type; NAC decreased systemic IL-1β and KC/GRO concentrations in mdx mice. We reveal that NAC treatment improved mdx diaphragm force-generating capacity associated with beneficial anti-inflammatory and anti-fibrotic effects. These data support the potential use of NAC as an adjunctive therapy in human dystrophinopathies.
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Trajanovska S, Ban J, Huang J, Gregorevic P, Morsch M, Allen DG, Phillips WD. Muscle specific kinase protects dystrophic mdx mouse muscles from eccentric contraction-induced loss of force-producing capacity. J Physiol 2019; 597:4831-4850. [PMID: 31340406 DOI: 10.1113/jp277839] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/17/2019] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS Adeno-associated viral vector was used to elevate the expression of muscle specific kinase (MuSK) and rapsyn (a cytoplasmic MuSK effector protein) in the tibialis anterior muscle of wild-type and dystrophic (mdx) mice. In mdx mice, enhanced expression of either MuSK or rapsyn ameliorated the acute loss of muscle force associated with strain injury. Increases in sarcolemmal immunolabelling for utrophin and β-dystroglycan suggest a mechanism for the protective effect of MuSK in mdx muscles. MuSK also caused subtle changes to the structure and function of the neuromuscular junction, suggesting novel roles for MuSK in muscle physiology and pathophysiology. ABSTRACT Muscle specific kinase (MuSK) has a well-defined role in stabilizing the developing mammalian neuromuscular junction, but MuSK might also be protective in some neuromuscular diseases. In the dystrophin-deficient mdx mouse model of Duchenne muscular dystrophy, limb muscles are especially fragile. We injected the tibialis anterior muscle of 8-week-old mdx and wild-type (C57BL10) mice with adeno-associated viral vectors encoding either MuSK or rapsyn (a cytoplasmic MuSK effector protein) fused to green fluorescent protein (MuSK-GFP and rapsyn-GFP, respectively). Contralateral muscles injected with empty vector served as controls. One month later mice were anaesthetized with isoflurane and isometric force-producing capacity was recorded from the distal tendon. MuSK-GFP caused an unexpected decay in nerve-evoked tetanic force, both in wild-type and mdx muscles, without affecting contraction elicited by direct electrical stimulation of the muscle. Muscle fragility was probed by challenging muscles with a strain injury protocol consisting of a series of four strain-producing eccentric contractions in vivo. When applied to muscles of mdx mice, eccentric contraction produced an acute 27% reduction in directly evoked muscle force output, affirming the susceptibility of mdx muscles to strain injury. mdx muscles overexpressing MuSK-GFP or rapsyn-GFP exhibited significantly milder force deficits after the eccentric contraction challenge (15% and 14%, respectively). The protective effect of MuSK-GFP in muscles of mdx mice was associated with increased immunolabelling for utrophin and β-dystroglycan in the sarcolemma. Elevating the expression of MuSK or rapsyn revealed several distinct synaptic and extrasynaptic effects, suggesting novel roles for MuSK signalling in muscle physiology and pathophysiology.
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Affiliation(s)
- S Trajanovska
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - J Ban
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - J Huang
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - P Gregorevic
- Department of Physiology, The University of Melbourne, Melbourne, Victoria, Australia.,Baker IDI Heart and Diabetes Institute, Melbourne, Victoria, Australia.,Department of Biochemistry and Molecular Biology, Monash University, Melbourne, Victoria, Australia.,Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - M Morsch
- Department of Biomedical Sciences, Macquarie University, Sydney, New South Wales, Australia
| | - D G Allen
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
| | - W D Phillips
- Physiology and Bosch Institute, University of Sydney, Sydney, New South Wales, Australia
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Bailey EC, Alrowaished SS, Kilroy EA, Crooks ES, Drinkert DM, Karunasiri CM, Belanger JJ, Khalil A, Kelley JB, Henry CA. NAD+ improves neuromuscular development in a zebrafish model of FKRP-associated dystroglycanopathy. Skelet Muscle 2019; 9:21. [PMID: 31391079 PMCID: PMC6685180 DOI: 10.1186/s13395-019-0206-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Accepted: 07/17/2019] [Indexed: 01/26/2023] Open
Abstract
Background Secondary dystroglycanopathies are muscular dystrophies that result from mutations in genes that participate in Dystroglycan glycosylation. Glycosylation of Dystroglycan is essential for muscle fibers to adhere to the muscle extracellular matrix (myomatrix). Although the myomatrix is disrupted in a number of secondary dystroglycanopathies, it is unknown whether improving the myomatrix is beneficial for these conditions. We previously determined that either NAD+ supplementation or overexpression of Paxillin are sufficient to improve muscle structure and the myomatrix in a zebrafish model of primary dystroglycanopathy. Here, we investigate how these modulations affect neuromuscular phenotypes in zebrafish fukutin-related protein (fkrp) morphants modeling FKRP-associated secondary dystroglycanopathy. Results We found that NAD+ supplementation prior to muscle development improved muscle structure, myotendinous junction structure, and muscle function in fkrp morphants. However, Paxillin overexpression did not improve any of these parameters in fkrp morphants. As movement also requires neuromuscular junction formation, we examined early neuromuscular junction development in fkrp morphants. The length of neuromuscular junctions was disrupted in fkrp morphants. NAD+ supplementation prior to neuromuscular junction development improved length. We investigated NMJ formation in dystroglycan (dag1) morphants and found that although NMJ morphology is disrupted in dag1 morphants, NAD+ is not sufficient to improve NMJ morphology in dag1 morphants. Ubiquitous overexpression of Fkrp rescued the fkrp morphant phenotype but muscle-specific overexpression only improved myotendinous junction structure. Conclusions These data indicate that Fkrp plays an early and essential role in muscle, myotendinous junction, and neuromuscular junction development. These data also indicate that, at least in the zebrafish model, FKRP-associated dystroglycanopathy does not exactly phenocopy DG-deficiency. Paxillin overexpression improves muscle structure in dag1 morphants but not fkrp morphants. In contrast, NAD+ supplementation improves NMJ morphology in fkrp morphants but not dag1 morphants. Finally, these data show that muscle-specific expression of Fkrp is insufficient to rescue muscle development and homeostasis. Electronic supplementary material The online version of this article (10.1186/s13395-019-0206-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Erin C Bailey
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, 217 Hitchner Hall, Orono, ME, 04469, USA
| | | | - Elisabeth A Kilroy
- Graduate School of Biomedical Sciences and Engineering, University of Maine, 217 Hitchner Hall, Orono, ME, 04469, USA
| | - Emma S Crooks
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA
| | - Daisy M Drinkert
- Molecular and Biomedical Sciences, University of Maine, Orono, ME, 04469, USA
| | - Chaya M Karunasiri
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.,Present Address: Tufts University School of Medicine, Boston, MA, 02111, USA
| | - Joseph J Belanger
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA.,Present Address: Lake Erie College of Osteopathic Medicine, Erie, PA, 16509, USA
| | - Andre Khalil
- Chemical and Biomedical Engineering, University of Maine, Orono, ME, 04469, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, 217 Hitchner Hall, Orono, ME, 04469, USA
| | - Joshua B Kelley
- Molecular and Biomedical Sciences, University of Maine, Orono, ME, 04469, USA.,Graduate School of Biomedical Sciences and Engineering, University of Maine, 217 Hitchner Hall, Orono, ME, 04469, USA
| | - Clarissa A Henry
- School of Biology and Ecology, University of Maine, Orono, ME, 04469, USA. .,Graduate School of Biomedical Sciences and Engineering, University of Maine, 217 Hitchner Hall, Orono, ME, 04469, USA.
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Slater CR. 'Fragmentation' of NMJs: a sign of degeneration or regeneration? A long journey with many junctions. Neuroscience 2019; 439:28-40. [PMID: 31129203 DOI: 10.1016/j.neuroscience.2019.05.017] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 05/07/2019] [Accepted: 05/07/2019] [Indexed: 12/13/2022]
Abstract
Mammalian neuromuscular junctions (NMJs) often consist of curved bands of synaptic contact, about 3-6 μm wide, which resemble pretzels. This contrasts with the NMJs of most animal species which consist of a cluster of separate synaptic spots, each of which is also about 3-6 μm across. In a number of situations, including a variety of disease states as well as normal ageing, mammalian NMJs acquire a more 'fragmented' appearance that resembles somewhat that of other species. This 'fragmentation' of the NMJ has sometimes been interpreted as a 'disintegration' or 'degeneration', with the suggestion that it might be associated with impaired neuromuscular transmission. An alternative view is that NMJ fragmentation is the outcome of a normal process by which the NMJ is maintained in an effective state. In this highly personal commentary, I cite a number of examples of this and point out that although the 'pretzel' form arises during normal development as a result of the sculpting of an immature synaptic 'plaque', in virtually all situations where new synaptic contact is established in adult mammals this occurs by the addition of new synaptic 'spots' rather than by the extension, or neoformation, of 'pretzels'. Further, where appropriate studies have been performed, no evidence of a correlation between the degree of fragmentation and the efficacy of transmission has emerged. It may therefore be more appropriate to consider NMJ 'fragmentation' as a form of regeneration, rather than of degeneration. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Clarke R Slater
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.
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Buratti P, Covatti C, Centenaro LA, Brancalhão RMC, Torrejais MM. Morphofunctional characteristics of skeletal muscle in rats with cerebral palsy. Int J Exp Pathol 2019; 100:49-59. [PMID: 30773727 DOI: 10.1111/iep.12304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 10/24/2018] [Accepted: 12/27/2018] [Indexed: 01/10/2023] Open
Abstract
Knowledge of skeletal muscle adaptations is important to understand the functional deficits in cerebral palsy (CP). This study aimed to investigate the morphofunctional characteristics of skeletal muscle in a CP animal model. Initially, pregnant Wistar rats were injected intraperitoneally with saline or lipopolysaccharide over the last five days of pregnancy. The control group (n = 8) consisted of male pups born to females injected with saline. The CP group (n = 8) consisted of male pups born to females injected with lipopolysaccharide, which were submitted to perinatal anoxia [day of birth, postnatal day 0 (P0)] and sensorimotor restriction (P1-P30). The open-field test was undertaken on P29 and P45. On P48, the animals were weighed, and the plantaris muscle was collected and its weight and length were measured. Transverse sections were stained with haematoxylin-eosin, NADH-TR, Masson's trichrome and non-specific esterase reaction for analysis. and transmission electron microscopy was performed. In the CP group, reductions were observed in mobility time, number of crossings and rearing frequency, body weight, muscle weight and length, and nucleus-to-fibre and capillary-to-fibre ratios. There was a statistically significant increase in the percentage area of the muscle section occupied by collagen; reduction in the area and increase in the number of type I muscle fibres; increase in myofibrillar disorganization and Z-line disorganization and dissolution; and reduction in the area and largest and smallest diameters of neuromuscular junctions. Thus this animal model of CP produced morphofunctional alterations in skeletal muscle, that were associated with evidence of motor deficits as demonstrated by the open-field test.
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Affiliation(s)
- Pâmela Buratti
- Programa de Pós-Graduação em Biociências e Saúde, Universidade Estadual do Oeste do Paraná - UNIOESTE, Cascavel, Paraná, Brazil
| | - Caroline Covatti
- Programa de Pós-Graduação em Biociências e Saúde, Universidade Estadual do Oeste do Paraná - UNIOESTE, Cascavel, Paraná, Brazil
| | - Lígia Aline Centenaro
- Centro de Ciências Médicas e Farmacêuticas, Universidade Estadual do Oeste do Paraná - UNIOESTE, Cascavel, Paraná, Brazil
| | - Rose Meire Costa Brancalhão
- Programa de Pós-Graduação em Biociências e Saúde, Universidade Estadual do Oeste do Paraná - UNIOESTE, Cascavel, Paraná, Brazil
| | - Marcia Miranda Torrejais
- Programa de Pós-Graduação em Biociências e Saúde, Universidade Estadual do Oeste do Paraná - UNIOESTE, Cascavel, Paraná, Brazil
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45
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Villalón E, Shababi M, Kline R, Lorson ZC, Florea KM, Lorson CL. Selective vulnerability in neuronal populations in nmd/SMARD1 mice. Hum Mol Genet 2019; 27:679-690. [PMID: 29272405 DOI: 10.1093/hmg/ddx434] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 12/15/2017] [Indexed: 12/12/2022] Open
Abstract
Spinal muscular atrophy with respiratory distress type 1 (SMARD1) is an autosomal recessive motor neuron disease causing distal limb muscle atrophy that progresses proximally and is accompanied by diaphragmatic paralysis. Neuromuscular junction (NMJ) alterations have been reported in muscles of SMARD1 model mice, known as nmd mice, with varying degrees of severity, suggesting that different muscles are specifically and selectively resistant or susceptible to denervation. To evaluate the extent of NMJ pathology in a broad range of muscles, a panel of axial and appendicular muscles were isolated and immunostained from nmd mice. These analyses revealed that selective distal appendage muscles were highly vulnerable to denervation. Susceptibility to pathology was not limited to NMJ alterations, but included defects in myelination within those neurons innervating susceptible muscles. Interestingly, end plate fragmentation was present within all muscles independent of the extent of NMJ alterations, suggesting that end plate fragmentation is an early hallmark of SMARD1 pathogenesis. Expressing the full-length IGHMBP2 cDNA using an adeno-associated virus (AAV9) significantly decreased all aspects of muscle and nerve disease pathology. These results shed new light onto the pathogenesis of SMARD1 by identifying specific motor units that are resistant and susceptible to neurodegeneration in an important model of SMARD1.
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Affiliation(s)
- Eric Villalón
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Monir Shababi
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Rachel Kline
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Zachary C Lorson
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Kyra M Florea
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
| | - Christian L Lorson
- Department of Veterinary Pathobiology, Christopher S. Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA.,Department of Veterinary Pathobiology, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Abstract
Skeletal muscle has an extraordinary capacity to regenerate after injury and trauma. The muscle repair mechanism is a complex process orchestrated by multiple steps. In neuromuscular disorders such as Duchenne muscular dystrophy (DMD), the pathological consequences of the lack of dystrophin and the loss of the dystrophin-associated protein complex are dramatic, with a progressive cascade of events, such as continual influx of inflammation, repeated cycles of degeneration and impaired regeneration. Thus, muscle regeneration is a hallmark of the disease and careful monitoring of regenerative processes with robust markers should provide useful information to the field. Since decades, several indices of regeneration such as centronucleation and fibre size have been commonly used. In the present review, we discuss the impaired regenerative process in DMD, the common and new indices of regeneration and their associated methodologies. We notably highlight the regenerative marker embryonic myosin as a robust indicator of muscle regeneration. We also describe new quantitative methodologies offering the possibility of using a panel of translational regenerative biomarkers to obtain a more complete view of the regeneration processes. Upregulation of utrophin, an autosomal and functional paralogue of dystrophin, is one of the most promising therapeutic strategies as it targets the primary cause of the disease and is applicable to all DMD patients regardless their genetic defects. As utrophin is a regeneration associated protein increased in dystrophic muscle, we discuss the correlation of utrophin levels after drug treatment with regeneration markers. The recent advances in technologies and complementary markers of muscle regeneration described in this review, provide an unprecedented opportunity to develop more robust utrophin DMD based strategies for all DMD patients.
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Affiliation(s)
- Simon Guiraud
- MDUK Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, Oxford, UK
| | - Kay E Davies
- MDUK Oxford Neuromuscular Centre, Department of Physiology, Anatomy and Genetics, Oxford, UK
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47
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Wilson RJ, Drake JC, Cui D, Ritger ML, Guan Y, Call JA, Zhang M, Leitner LM, Gödecke A, Yan Z. Voluntary running protects against neuromuscular dysfunction following hindlimb ischemia-reperfusion in mice. J Appl Physiol (1985) 2019; 126:193-201. [PMID: 30433863 PMCID: PMC6383643 DOI: 10.1152/japplphysiol.00358.2018] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 12/20/2022] Open
Abstract
Ischemia-reperfusion (IR) due to temporary restriction of blood flow causes tissue/organ damages under various disease conditions, including stroke, myocardial infarction, trauma, and orthopedic surgery. In the limbs, IR injury to motor nerves and muscle fibers causes reduced mobility and quality of life. Endurance exercise training has been shown to increase tissue resistance to numerous pathological insults. To elucidate the impact of endurance exercise training on IR injury in skeletal muscle, sedentary and exercise-trained mice (5 wk of voluntary running) were subjected to ischemia by unilateral application of a rubber band tourniquet above the femur for 1 h, followed by reperfusion. IR caused significant muscle injury and denervation at neuromuscular junction (NMJ) as early as 3 h after tourniquet release as well as depressed muscle strength and neuromuscular transmission in sedentary mice. Despite similar degrees of muscle atrophy and oxidative stress, exercise-trained mice had significantly reduced muscle injury and denervation at NMJ with improved regeneration and functional recovery following IR. Together, these data suggest that endurance exercise training preserves motor nerve and myofiber structure and function from IR injury and promote functional regeneration. NEW & NOTEWORTHY This work provides the first evidence that preemptive voluntary wheel running reduces neuromuscular dysfunction following ischemia-reperfusion injury in skeletal muscle. These findings may alter clinical practices in which a tourniquet is used to modulate blood flow.
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Affiliation(s)
- Rebecca J Wilson
- Department of Biochemistry and Molecular Genetics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Joshua C Drake
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Di Cui
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Matthew L Ritger
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Yuntian Guan
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Jarrod A Call
- Department of Kinesiology, University of Georgia , Athens, Georgia
- Regenerative Bioscience Center, University of Georgia , Athens, Georgia
| | - Mei Zhang
- Department of Medicine, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
| | - Lucia M Leitner
- Institute of Cardiovascular Physiology, Heinrich Heine University of Düsseldorf , Düsseldorf , Germany
| | - Axel Gödecke
- Institute of Cardiovascular Physiology, Heinrich Heine University of Düsseldorf , Düsseldorf , Germany
| | - Zhen Yan
- Department of Medicine, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
- Department of Pharmacology, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
- Department of Molecular Physiology and Biological Physics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
- Center for Skeletal Muscle Research, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine , Charlottesville, Virginia
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48
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Lindsay A, Larson AA, Verma M, Ervasti JM, Lowe DA. Isometric resistance training increases strength and alters histopathology of dystrophin-deficient mouse skeletal muscle. J Appl Physiol (1985) 2018; 126:363-375. [PMID: 30571283 DOI: 10.1152/japplphysiol.00948.2018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Mutation to the dystrophin gene causes skeletal muscle weakness in patients with Duchenne muscular dystrophy (DMD) or Becker muscular dystrophy (BMD). Deliberation continues regarding implications of prescribing exercise for these patients. The purpose of this study was to determine whether isometric resistance exercise (~10 tetanic contractions/session) improves skeletal muscle strength and histopathology in the mdx mouse model of DMD. Three isometric training sessions increased in vivo isometric torque (22%) and contractility rates (54%) of anterior crural muscles of mdx mice. Mice expressing a BMD-causing missense mutated dystrophin on the mdx background showed comparable increases in torque (22%), while wild-type mice showed less change (11%). Increases in muscle function occurred within 1 h and peaked 3 days posttraining; however, the adaptation was lost after 7 days unless retrained. Six isometric training sessions over 4 wk caused increased isometric torque (28%) and contractility rates (22-28%), reduced fibrosis, as well as greater uniformity of fiber cross-sectional areas, fewer embryonic myosin heavy-chain-positive fibers, and more satellite cells in tibialis anterior muscle compared with the contralateral untrained muscle. Ex vivo functional analysis of isolated extensor digitorum longus (EDL) muscle from the trained hindlimb revealed greater absolute isometric force, lower passive stiffness, and a lower susceptibility to eccentric contraction-induced force loss compared with untrained EDL muscle. Overall, these data support the concept that exercise training in the form of isometric tetanic contractions can improve contractile function of dystrophin-deficient muscle, indicating a potential role for enhancing muscle strength in patients with DMD and BMD. NEW & NOTEWORTHY We focused on adaptive responses of dystrophin-deficient mouse skeletal muscle to isometric contraction training and report that in the absence of dystrophin (or in the presence of a mutated dystrophin), strength and muscle histopathology are improved. Results suggest that the strength gains are associated with fiber hypertrophy, reduced fibrosis, increased number of satellite cells, and blunted eccentric contraction-induced force loss in vitro. Importantly, there was no indication that the isometric exercise training was deleterious to dystrophin-deficient muscle.
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Affiliation(s)
- Angus Lindsay
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota.,Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Alexie A Larson
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota
| | - Mayank Verma
- Department of Integrative Biology and Physiology, University of Minnesota , Minneapolis, Minnesota.,Medical Scientist Training Program, University of Minnesota Medical School , Minneapolis, Minnesota
| | - James M Ervasti
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota , Minneapolis, Minnesota
| | - Dawn A Lowe
- Division of Rehabilitation Science and Division of Physical Therapy, Department of Rehabilitation Medicine, University of Minnesota , Minneapolis, Minnesota
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Kravtsova VV, Timonina NA, Zakir’yanova GF, Sokolova AV, Mikhailov VM, Zefirov AL, Krivoi II. The Structural and Functional Characteristics of the Motor End Plates of Dysferlin-Deficient Mice. NEUROCHEM J+ 2018. [DOI: 10.1134/s1819712418040049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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50
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Vilchinskaya NA, Krivoi II, Shenkman BS. AMP-Activated Protein Kinase as a Key Trigger for the Disuse-Induced Skeletal Muscle Remodeling. Int J Mol Sci 2018; 19:ijms19113558. [PMID: 30424476 PMCID: PMC6274864 DOI: 10.3390/ijms19113558] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 11/02/2018] [Accepted: 11/09/2018] [Indexed: 12/25/2022] Open
Abstract
Molecular mechanisms that trigger disuse-induced postural muscle atrophy as well as myosin phenotype transformations are poorly studied. This review will summarize the impact of 5′ adenosine monophosphate -activated protein kinase (AMPK) activity on mammalian target of rapamycin complex 1 (mTORC1)-signaling, nuclear-cytoplasmic traffic of class IIa histone deacetylases (HDAC), and myosin heavy chain gene expression in mammalian postural muscles (mainly, soleus muscle) under disuse conditions, i.e., withdrawal of weight-bearing from ankle extensors. Based on the current literature and the authors’ own experimental data, the present review points out that AMPK plays a key role in the regulation of signaling pathways that determine metabolic, structural, and functional alternations in skeletal muscle fibers under disuse.
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Affiliation(s)
| | - Igor I Krivoi
- Department of General Physiology, St. Petersburg State University, St. Petersburg 199034, Russia.
| | - Boris S Shenkman
- Myology Laboratory, Institute of Biomedical Problems RAS, Moscow 123007, Russia.
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