scholarly journals Macrophages promote muscle membrane repair and muscle fibre growth and regeneration during modified muscle loading in micein vivo

2006 ◽  
Vol 578 (1) ◽  
pp. 327-336 ◽  
Author(s):  
James G. Tidball ◽  
Michelle Wehling-Henricks
Keyword(s):  
Muscle Fibre ◽  
Muscle Membrane ◽  
Membrane Repair ◽  
Fibre Growth ◽  
Muscle Loading

scholarly journals Membrane blebbing as an assessment of functional rescue of dysferlin-deficient human myotubes via nonsense suppression

2010 ◽  
Vol 109 (3) ◽  
pp. 901-905 ◽  
Author(s):  
Bingjing Wang ◽  
Zhaohui Yang ◽  
Becky K. Brisson ◽  
Huisheng Feng ◽  
Zhiqian Zhang ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Stop Codon ◽  
Premature Stop Codon ◽  
Nonsense Suppression ◽  
Muscle Membrane ◽  
Membrane Repair ◽  
Vitro Assay ◽  
Membrane Blebbing ◽  
Human Myotubes

Mutations that result in the loss of the protein dysferlin result in defective muscle membrane repair and cause either a form of limb girdle muscular dystrophy (type 2B) or Miyoshi myopathy. Most patients are compound heterozygotes, often carrying one allele with a nonsense mutation. Using dysferlin-deficient mouse and human myocytes, we demonstrated that membrane blebbing in skeletal muscle myotubes in response to hypotonic shock requires dysferlin. Based on this, we developed an in vitro assay to assess rescue of dysferlin function in skeletal muscle myotubes. This blebbing assay may be useful for drug discovery/validation for dysferlin deficiency. With this assay, we demonstrate that the nonsense suppression drug, ataluren (PTC124), is able to induce read-through of the premature stop codon in a patient with a R1905X mutation in dysferlin and produce sufficient functional dysferlin (∼15% of normal levels) to rescue myotube membrane blebbing. Thus ataluren is a potential therapeutic for dysferlin-deficient patients harboring nonsense mutations.

scholarly journals Fer1L5, a Dysferlin Homologue Present in Vesicles and Involved in C2C12 Myoblast Fusion and Membrane Repair

Biology ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 386
Author(s):  
R. Usha Kalyani ◽  
K. Perinbam ◽  
P. Jeyanthi ◽  
Naif Abdullah Al-Dhabi ◽  
Mariadhas Valan Arasu ◽  
...  
Keyword(s):  
Myoblast Fusion ◽  
C2c12 Cells ◽  
Muscle Membrane ◽  
C2c12 Myoblast ◽  
Related Protein ◽  
Membrane Repair ◽  
Ionic Detergent ◽  
Biochemical Fractionation ◽  
Two Stages

Fer1L5 is a dysferlin and myoferlin related protein, which has been predicted to have a role in vesicle trafficking and muscle membrane fusion events. Mutations in dysferlin and otoferlin genes cause heredity diseases: muscular dystrophy and deafness in humans, respectively. Dysferlin is implicated in membrane repair. Myoferlin has a role in myogenesis. In this study, we investigated the role of the Fer1L5 protein during myoblast fusion and membrane repair. To study the functions of Fer1L5 we used confocal microscopy, biochemical fractionation, Western blot analysis and multiphoton laser wounding assay. By immunolabelling, Fer1L5 was detected in vesicular structures. By biochemical fractionation Fer1L5 was observed in low density vesicles. Our studies show that the membranes of Fer1L5 vesicles are non-resistant to non-ionic detergent. Partial co-staining of Fer1L5 with other two ferlin vesicles, respectively, was observed. Fer1L5 expression was highly detected at the fusion sites of two apposed C2C12 myoblast membranes and its expression level gradually increased at D2 and reached a maximum at day 4 before decreasing during further differentiation. Our studies showed that Fer1L5 has fusion defects during myoblast fusion and impaired membrane repair when the C2C12 cultures were incubated with inhibitory Fer1L5 antibodies. In C2C12 cells Fer1L5 vesicles are involved in two stages, the fusion of myoblasts and the formation of large myotubes. Fer1L5 also plays a role in membrane repair.

scholarly journals Post-synaptic morphology of mouse neuromuscular junctions is linked to muscle fibre type

2020 ◽  
Author(s):  
Aleksandra M. Mech ◽  
Anna-Leigh Brown ◽  
Giampietro Schiavo ◽  
James N. Sleigh
Keyword(s):  
Motor Neuron ◽  
Muscle Fibre ◽  
Fibre Type ◽  
Neuromuscular Junctions ◽  
Fibre Diameter ◽  
Neuromuscular Diseases ◽  
Neuronal Morphology ◽  
Muscle Fibre Type ◽  
Muscle Membrane ◽  
Muscle Fibres

AbstractThe neuromuscular junction (NMJ) is the highly specialised peripheral synapse formed between lower motor neuron terminals and muscle fibres. Post-synaptic acetylcholine receptors (AChRs), which are found in high density in the muscle membrane, bind to acetylcholine released into the synaptic cleft of the NMJ, ultimately facilitating the conversion of motor action potentials to muscle contractions. NMJs have been studied for many years as a general model for synapse formation, development and function, and are known to be early sites of pathological changes in many neuromuscular diseases. However, information is limited on the diversity of NMJs in different muscles, whether muscle fibre type impacts NMJ morphology and growth, and the relevance of these parameters to neuropathology. Here, this crucial gap was addressed using a robust and standardised semi-automated workflow called NMJ-morph to quantify features of pre- and post-synaptic NMJ architecture in an unbiased manner. Five wholemount muscles from wild-type mice were dissected and compared at immature (post-natal day, P7) and early adult (P31-32) timepoints. Post-synaptic AChR morphology was found to be more variable between muscles than that of the motor neuron terminal and there were greater differences in the developing NMJ than at the mature synapse. Post-synaptic architecture, but not neuronal morphology or post-natal synapse growth, correlates with fibre type and is largely independent of muscle fibre diameter. Counter to previous observations, this study indicates that smaller NMJs tend to innervate muscles with higher proportions of fast twitch fibres and that NMJ growth rate is not conserved across all muscles. Furthermore, healthy pre- and post-synaptic NMJ morphological parameters were collected for five anatomically and functionally distinct mouse muscles, generating reference data that will be useful for the future assessment of neuromuscular disease models.Graphical Abstract

A comparison of skeletal muscle fibre growth in broiler and layer chickens

2003 ◽  
Vol 44 ◽  
pp. S33-S34 ◽  
Author(s):  
V.E. Cooke ◽  
S. Gilpin ◽  
M. Mahon ◽  
D.A. Sandercock ◽  
M. A. Mitchell
Keyword(s):  
Skeletal Muscle ◽  
Muscle Fibre ◽  
Skeletal Muscle Fibre ◽  
Fibre Growth ◽  
Layer Chickens

scholarly journals MG53 Preserves Neuromuscular Junction Integrity and Alleviates ALS Disease Progression

Antioxidants ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1522
Author(s):  
Jianxun Yi ◽  
Ang Li ◽  
Xuejun Li ◽  
Kiho Park ◽  
Xinyu Zhou ◽  
...  
Keyword(s):  
Disease Progression ◽  
Neuromuscular Junctions ◽  
Muscle Protein ◽  
Diaphragm Muscle ◽  
Muscle Membrane ◽  
Membrane Repair ◽  
Plasma Membrane Repair ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Increased Susceptibility

Respiratory failure from progressive respiratory muscle weakness is the most common cause of death in amyotrophic lateral sclerosis (ALS). Defects in neuromuscular junctions (NMJs) and progressive NMJ loss occur at early stages, thus stabilizing and preserving NMJs represents a potential therapeutic strategy to slow ALS disease progression. Here we demonstrate that NMJ damage is repaired by MG53, an intrinsic muscle protein involved in plasma membrane repair. Compromised diaphragm muscle membrane repair and NMJ integrity are early pathological events in ALS. Diaphragm muscles from ALS mouse models show increased susceptibility to injury and intracellular MG53 aggregation, which is also a hallmark of human muscle samples from ALS patients. We show that systemic administration of recombinant human MG53 protein in ALS mice protects against injury to diaphragm muscle, preserves NMJ integrity, and slows ALS disease progression. As MG53 is present in circulation in rodents and humans under physiological conditions, our findings provide proof-of-concept data supporting MG53 as a potentially safe and effective therapy to mitigate ALS progression.

scholarly journals Proteasome Inhibitors Reduce Thrombospondin-1 Release in Human Dysferlin-Deficient Myotubes

2019 ◽  
Author(s):  
Esther Fernández-Simón ◽  
Cinta Lleixà ◽  
Xavier Suarez-Calvet ◽  
Jordi Diaz-Manera ◽  
Isabel Illa ◽  
...  
Keyword(s):  
Vitamin D3 ◽  
Transmembrane Protein ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Muscle Membrane ◽  
Enzyme Linked Immunosorbent Assay ◽  
Missense Mutations ◽  
Membrane Repair ◽  
Thrombospondin 1 ◽  
Ubiquitin Proteasome

Abstract Background: Dysferlin is a type-II transmembrane protein and the causative gene of dysferlinopathies, which are characterized by absence or marked reduction in dysferlin protein and muscle weakness. Dysferlin is implicated in vesicle fusion, trafficking, and membrane repair. The muscle biopsy of patients with dysferlinopathy is characterized by the presence of inflammatory infiltrates. Release of thrombospondin-1 (TSP-1) by dysferlin deficient muscle has been reported as a possible factor of the inflammation observed in the muscle of both human and mouse models of dysferlinopathy. It has also been reported that treatment with vitamin D3 enhances dysferlin expression. The ubiquitin-proteasome system recognizes and removes proteins that fail to fold or assemble properly and previous studies suggest that its inhibition could have a therapeutic implication in muscle dystrophies. Here we assessed whether inhibition of the ubiquitin proteasome system prevented degradation of dysferlin in immortalized myoblasts from a patient carrying two missense mutationsMethods: Dysferlin deficient myotubes were treated with EB1089, a vitamin D3 analog, oprozomib and ixazomib to assess proteasome inhibition. Western blot was performed to analyze the effect of the different treatments on the recovery of dysferlin and myogenin expression. TSP-1 was quantified using Enzyme Linked Immunosorbent Assay to analyze the effect of these drugs on its release.A membrane repair assay was designed to assess the ability of treated myotubes to recover after membrane injury. Data were analyzed using a one-way ANOVA test followed by by Tukey post hoc test and analysis of variance. Ap≤0.05 was considered statistically significant. Results : Treatment with proteasome inhibitors and EB1089 resulted in a slight increase of dysferlin expression which was accompanied by a low increase of myogenin expression. Also, EB1089 and proteasome inhibitors reduced the release of TSP-1 in myotubes from a dysferlinopathy patient. However, the increase of dysferlin had no effect on the repair of muscle membrane after injury. Conclusions: Our findings indicate that the ubiquitin-proteasome system might not be the main mechanism of mutant dysferlin degradation. However, its inhibition could help to improve muscle inflammation by reducing TSP-1 release.

scholarly journals Impairments in contractility and cytoskeletal organisation cause nuclear defects in nemaline myopathy

2019 ◽  
Author(s):  
Jacob A Ross ◽  
Yotam Levy ◽  
Michela Ripolone ◽  
Justin S Kolb ◽  
Mark Turmaine ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Nuclear Envelope ◽  
Muscle Fibre ◽  
Nemaline Myopathy ◽  
Cytoskeletal Proteins ◽  
Muscle Fibres ◽  
Filament Structure ◽  
Transcriptional Alterations ◽  
Fibre Growth ◽  
Chromatin Arrangement

AbstractNemaline myopathy (NM) is a genetically heterogeneous skeletal muscle disorder caused by mutations predominately affecting contractile filaments, in particular thin filament structure and/or regulation. The underlying cellular pathophysiology of this disease remains largely unclear. Here, we report novel pathological defects in skeletal muscle fibres of mice and patients with NM, including disrupted nuclear envelope, altered chromatin arrangement, and disorganisation of the cortical cytoskeleton. We demonstrate that such nuclear defects are caused by impairment of muscle fibre contractility, and that cytoskeletal organisation determines nuclear morphology. Our results overlap with findings in diseases caused by mutations in nuclear envelope or cytoskeletal proteins. Given the important role of nuclear shape and envelope in regulating gene expression, and the cytoskeleton in maintaining muscle fibre integrity, our findings are likely to underlie some of the hallmarks of NM, which include broad transcriptional alterations, arrested muscle fibre growth, contractile filament disarray and altered mechanical properties.

scholarly journals MG53 preserves neuromuscular junction integrity and alleviates ALS disease progression

2021 ◽  
Author(s):  
Jianxun Yi ◽  
Ang Li ◽  
Xuejun Li ◽  
Ki Ho Park ◽  
Xinyu Zhou ◽  
...  
Keyword(s):  
Disease Progression ◽  
Neuromuscular Junctions ◽  
Muscle Protein ◽  
Diaphragm Muscle ◽  
Muscle Membrane ◽  
Membrane Repair ◽  
Plasma Membrane Repair ◽  
Als Patients ◽  
Lateral Sclerosis ◽  
Increased Susceptibility

AbstractRespiratory failure from progressive respiratory muscle weakness is the most common cause of death in amyotrophic lateral sclerosis (ALS). Defects in neuromuscular junctions (NMJs) and progressive NMJ loss occur at early stages, thus stabilizing and preserving NMJs represents a potential therapeutic strategy to slow ALS disease progression. Here we demonstrate that NMJ damage is repaired by MG53, an intrinsic muscle protein involved in plasma membrane repair. Compromised diaphragm muscle membrane repair and NMJ integrity are early pathological findings in ALS. Diaphragm muscles from ALS mouse models show increased susceptibility to injury and intracellular MG53 aggregation, which is also a hallmark of human muscle samples from ALS patients. We show that systemic administration of recombinant human MG53 protein (rhMG53) in ALS mice protects against injury to diaphragm muscle, preserves NMJ integrity, and slows ALS disease progression. As MG53 is present in circulation in rodents and humans under physiological conditions, our findings provide proof-of-concept data supporting MG53 as a potentially safe and effective therapy to mitigate ALS progression.

scholarly journals Proteasome inhibitors reduce thrombospondin-1 release in human dysferlin-deficient myotubes

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Esther Fernández-Simón ◽  
Cinta Lleixà ◽  
Xavier Suarez-Calvet ◽  
Jordi Diaz-Manera ◽  
Isabel Illa ◽  
...  
Keyword(s):  
Vitamin D3 ◽  
Transmembrane Protein ◽  
Proteasome Inhibitors ◽  
Ubiquitin Proteasome System ◽  
Muscle Membrane ◽  
Enzyme Linked Immunosorbent Assay ◽  
Missense Mutations ◽  
Membrane Repair ◽  
Thrombospondin 1 ◽  
Ubiquitin Proteasome

Abstract Background Dysferlinopathies are a group of muscle disorders causing muscle weakness and absence or low levels of dysferlin, a type-II transmembrane protein and the causative gene of these dystrophies. Dysferlin is implicated in vesicle fusion, trafficking, and membrane repair. Muscle biopsy of patients with dysferlinopathy is characterized by the presence of inflammatory infiltrates. Studies in the muscle of both human and mouse models of dysferlinopathy suggest dysferlin deficient muscle plays a role in this inflammation by releasing thrombospondin-1. It has also been reported that vitamin D3 treatment enhances dysferlin expression. The ubiquitin-proteasome system recognizes and removes proteins that fail to fold or assemble properly and previous studies suggest that its inhibition could have a therapeutic effect in muscle dystrophies. Here we assessed whether inhibition of the ubiquitin proteasome system prevented degradation of dysferlin in immortalized myoblasts from a patients with two missense mutations in exon 44. Methods To assess proteasome inhibition we treated dysferlin deficient myotubes with EB1089, a vitamin D3 analog, oprozomib and ixazomib. Western blot was performed to analyze the effect of these treatments on the recovery of dysferlin and myogenin expression. TSP-1 was quantified using the enzyme-linked immunosorbent assay to analyze the effect of these drugs on its release. A membrane repair assay was designed to assess the ability of treated myotubes to recover after membrane injury and fusion index was also measured with the different treatments. Data were analyzed using a one-way ANOVA test followed by Tukey post hoc test and analysis of variance. A p ≤ 0.05 was considered statistically significant. Results Treatment with proteasome inhibitors and EB1089 resulted in a trend towards an increase in dysferlin and myogenin expression. Furthermore, EB1089 and proteasome inhibitors reduced the release of TSP-1 in myotubes. However, no effect was observed on the repair of muscle membrane after injury. Conclusions Our findings indicate that the ubiquitin-proteasome system might not be the main mechanism of mutant dysferlin degradation. However, its inhibition could help to improve muscle inflammation by reducing TSP-1 release.

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