1
|
Juros D, Avila MF, Hastings RL, Pendragon A, Wilson L, Kay J, Valdez G. Cellular and molecular alterations to muscles and neuromuscular synapses in a mouse model of MEGF10-related myopathy. Skelet Muscle 2024; 14:10. [PMID: 38760872 PMCID: PMC11100254 DOI: 10.1186/s13395-024-00342-6] [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: 02/27/2024] [Accepted: 05/04/2024] [Indexed: 05/19/2024] Open
Abstract
Loss-of-function mutations in MEGF10 lead to a rare and understudied neuromuscular disorder known as MEGF10-related myopathy. There are no treatments for the progressive respiratory distress, motor impairment, and structural abnormalities in muscles caused by the loss of MEGF10 function. In this study, we deployed cellular and molecular assays to obtain additional insights about MEGF10-related myopathy in juvenile, young adult, and middle-aged Megf10 knockout (KO) mice. We found fewer muscle fibers in juvenile and adult Megf10 KO mice, supporting published studies that MEGF10 regulates myogenesis by affecting satellite cell differentiation. Interestingly, muscle fibers do not exhibit morphological hallmarks of atrophy in either young adult or middle-aged Megf10 KO mice. We next examined the neuromuscular junction (NMJ), in which MEGF10 has been shown to concentrate postnatally, using light and electron microscopy. We found early and progressive degenerative features at the NMJs of Megf10 KO mice that include increased postsynaptic fragmentation and presynaptic regions not apposed by postsynaptic nicotinic acetylcholine receptors. We also found perisynaptic Schwann cells intruding into the NMJ synaptic cleft. These findings strongly suggest that the NMJ is a site of postnatal pathology in MEGF10-related myopathy. In support of these cellular observations, RNA-seq analysis revealed genes and pathways associated with myogenesis, skeletal muscle health, and NMJ stability dysregulated in Megf10 KO mice compared to wild-type mice. Altogether, these data provide new and valuable cellular and molecular insights into MEGF10-related myopathy.
Collapse
Affiliation(s)
- Devin Juros
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | | | - Robert Louis Hastings
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Ariane Pendragon
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
| | - Liam Wilson
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA
| | - Jeremy Kay
- Department of Neurobiology, Duke University School of Medicine, Durham, NC, USA
- Department of Ophthalmology, Duke University School of Medicine, Durham, NC, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship St, Providence, RI, 02903, USA.
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science, Center on the Biology of Aging, Brown University, Providence, RI, USA.
| |
Collapse
|
2
|
Herbst R, Huijbers MG, Oury J, Burden SJ. Building, Breaking, and Repairing Neuromuscular Synapses. Cold Spring Harb Perspect Biol 2024; 16:a041490. [PMID: 38697654 PMCID: PMC11065174 DOI: 10.1101/cshperspect.a041490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
A coordinated and complex interplay of signals between motor neurons, skeletal muscle cells, and Schwann cells controls the formation and maintenance of neuromuscular synapses. Deficits in the signaling pathway for building synapses, caused by mutations in critical genes or autoantibodies against key proteins, are responsible for several neuromuscular diseases, which cause muscle weakness and fatigue. Here, we describe the role that four key genes, Agrin, Lrp4, MuSK, and Dok7, play in this signaling pathway, how an understanding of their mechanisms of action has led to an understanding of several neuromuscular diseases, and how this knowledge has contributed to emerging therapies for treating neuromuscular diseases.
Collapse
Affiliation(s)
- Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, 1090 Vienna, Austria
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Centre LUMC, 2300 RC Leiden, the Netherlands
- Department of Neurology, Leiden University Medical Centre LUMC, 2333 ZA Leiden, the Netherlands
| | - Julien Oury
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, New York 10016, USA
| | - Steven J Burden
- Neurology Department, Massachusetts General Hospital, Charlestown, Massachusetts 02129, USA
| |
Collapse
|
3
|
Wang Q, Cui C, Zhang N, Lin W, Chai S, Chow SKH, Wong RMY, Hu Y, Law SW, Cheung WH. Effects of physical exercise on neuromuscular junction degeneration during ageing: A systematic review. J Orthop Translat 2024; 46:91-102. [PMID: 38817243 PMCID: PMC11137388 DOI: 10.1016/j.jot.2024.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/27/2024] [Accepted: 03/31/2024] [Indexed: 06/01/2024] Open
Abstract
The neuromuscular junction (NMJ) is a specialized chemical synapse that converts neural impulses into muscle action. Age-associated NMJ degeneration, which involves nerve terminal and postsynaptic decline, denervation, and loss of motor units, significantly contributes to muscle weakness and dysfunction. Although physical training has been shown to make substantial modifications in NMJ of both young and aged animals, the results are often influenced by methodological variables in existing studies. Moreover, there is still lack of strong consensus on the specific effects of exercise on improving the morphology and function of the ageing NMJ. Consequently, the purpose of this study was to conduct a systematic review to elucidate the effects of exercise training on NMJ compartments in the elderly. We conducted a systematic review using PubMed, Embase, and Web of Science databases, employing relevant keywords. Two independent reviewers selected studies that detailed NMJ changes during exercise in ageing, written in English, and available in full text. In total, 20 papers were included. We examined the altered adaptation of the NMJ to exercise, focusing on presynaptic and postsynaptic structures and myofibers in older animals or humans. Our findings indicated that aged NMJs exhibited different adaptive responses to physical exercise compared to younger counterparts. Endurance training, compared with resistance and voluntary exercise regimens, was found to have a more pronounced effect on NMJ structural remodeling, particularly in fast twitch muscle fibers. Physical exercise was observed to promote the formation and maintenance of acetylcholine receptor (AChR) clusters by increasing the recombinant docking protein 7 (Dok7) expression and stabilizing Agrin and lipoprotein receptor-related protein 4 (LRP4). These insights suggest that research on exercise-related therapies could potentially attenuate the progression of neuromuscular degeneration. Translational potential of this article: This systematic review provides a detailed overview of the effects of different types of physical exercise on improving NMJ in the elderly, providing scientific support for the timely intervention of muscle degeneration in the elderly by physical exercise, and providing help for the development of new therapeutic interventions in the future.
Collapse
Affiliation(s)
- Qianjin Wang
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Can Cui
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Ning Zhang
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Wujian Lin
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Senlin Chai
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Simon Kwoon-Ho Chow
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Department of Orthopaedic Surgery, Stanford University, Stanford, CA, USA
| | - Ronald Man Yeung Wong
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Yong Hu
- Department of Orthopaedics and Traumatology, The University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Sheung Wai Law
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| | - Wing-Hoi Cheung
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
- Li Ka Shing Institute of Health Sciences, The Chinese University of Hong Kong, Hong Kong Special Administrative Region of China
| |
Collapse
|
4
|
Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. eLife 2024; 12:RP92644. [PMID: 38661532 PMCID: PMC11045223 DOI: 10.7554/elife.92644] [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] [Indexed: 04/26/2024] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7+satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12, along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro. Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible 'response biomarkers' in pre-clinical and clinical studies.
Collapse
Affiliation(s)
- Ang Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Jianxun Yi
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Xuejun Li
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Li Dong
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| | - Lyle W Ostrow
- Department of Neurology, Lewis Katz School of Medicine at Temple UniversityPhiladelphiaUnited States
| | - Jianjie Ma
- Department of Surgery, Division of Surgical Sciences, University of VirginiaCharlottesvilleUnited States
| | - Jingsong Zhou
- Department of Kinesiology, College of Nursing and Health Innovation, The University of Texas at ArlingtonArlingtonUnited States
| |
Collapse
|
5
|
Li A, Yi J, Li X, Dong L, Ostrow LW, Ma J, Zhou J. Distinct transcriptomic profile of satellite cells contributes to preservation of neuromuscular junctions in extraocular muscles of ALS mice. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.02.12.528218. [PMID: 36824725 PMCID: PMC9949002 DOI: 10.1101/2023.02.12.528218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neuromuscular disorder characterized by progressive weakness of almost all skeletal muscles, whereas extraocular muscles (EOMs) are comparatively spared. While hindlimb and diaphragm muscles of end-stage SOD1G93A (G93A) mice (a familial ALS mouse model) exhibit severe denervation and depletion of Pax7 + satellite cells (SCs), we found that the pool of SCs and the integrity of neuromuscular junctions (NMJs) are maintained in EOMs. In cell sorting profiles, SCs derived from hindlimb and diaphragm muscles of G93A mice exhibit denervation-related activation, whereas SCs from EOMs of G93A mice display spontaneous (non-denervation-related) activation, similar to SCs from wild-type mice. Specifically, cultured EOM SCs contain more abundant transcripts of axon guidance molecules, including Cxcl12 , along with more sustainable renewability than the diaphragm and hindlimb counterparts under differentiation pressure. In neuromuscular co-culture assays, AAV-delivery of Cxcl12 to G93A-hindlimb SC-derived myotubes enhances motor neuron axon extension and innervation, recapitulating the innervation capacity of EOM SC-derived myotubes. G93A mice fed with sodium butyrate (NaBu) supplementation exhibited less NMJ loss in hindlimb and diaphragm muscles. Additionally, SCs derived from G93A hindlimb and diaphragm muscles displayed elevated expression of Cxcl12 and improved renewability following NaBu treatment in vitro . Thus, the NaBu-induced transcriptomic changes resembling the patterns of EOM SCs may contribute to the beneficial effects observed in G93A mice. More broadly, the distinct transcriptomic profile of EOM SCs may offer novel therapeutic targets to slow progressive neuromuscular functional decay in ALS and provide possible "response biomarkers" in pre-clinical and clinical studies.
Collapse
|
6
|
Alava B, Hery G, Sidhom S, Gutierrez-Monreal M, Prokop S, Esser KA, Abisambra J. Targeted brain-specific tauopathy compromises peripheral skeletal muscle integrity and function. AGING BRAIN 2024; 5:100110. [PMID: 38419621 PMCID: PMC10900120 DOI: 10.1016/j.nbas.2024.100110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 02/16/2024] [Accepted: 02/21/2024] [Indexed: 03/02/2024] Open
Abstract
Tauopathies are neurodegenerative disorders in which the pathological intracellular aggregation of the protein tau causes cognitive deficits. Additionally, clinical studies report muscle weakness in populations with tauopathy. However, whether neuronal pathological tau species confer muscle weakness, and whether skeletal muscle maintains contractile capacity in primary tauopathy remains unknown. Here, we identified skeletal muscle abnormalities in a mouse model of primary tauopathy, expressing human mutant P301L-tau using adeno-associated virus serotype 8 (AAV8). AAV8-P301L mice showed grip strength deficits, hyperactivity, and abnormal histological features of skeletal muscle. Additionally, spatially resolved gene expression of muscle cross sections were altered in AAV8-P301L myofibers. Transcriptional changes showed alterations of genes encoding sarcomeric proteins, proposing a weakness phenotype. Strikingly, specific force of the soleus muscle was blunted in AAV8-P301L tau male mice. Our findings suggest tauopathy has peripheral consequences in skeletal muscle that contribute to weakness in tauopathy.
Collapse
Affiliation(s)
- Bryan Alava
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA
| | - Gabriela Hery
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA
| | - Silvana Sidhom
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | | | - Stefan Prokop
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA
- Department of Pathology, University of Florida, Gainesville, FL 32610, USA
| | - Karyn A. Esser
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | - Jose Abisambra
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, FL 32610, USA
- Department of Neuroscience, University of Florida, Gainesville, FL 32610, USA
- Brain Injury Rehabilitation and Neuroresilience (BRAIN) Center, University of Florida, Gainesville, FL 32601, USA
| |
Collapse
|
7
|
Eguchi T, Tezuka T, Watanabe Y, Inoue-Yamauchi A, Sagara H, Ozawa M, Yamanashi Y. Calcium-binding protein 7 expressed in muscle negatively regulates age-related degeneration of neuromuscular junctions in mice. iScience 2024; 27:108997. [PMID: 38327785 PMCID: PMC10847746 DOI: 10.1016/j.isci.2024.108997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2023] [Revised: 12/05/2023] [Accepted: 01/19/2024] [Indexed: 02/09/2024] Open
Abstract
The neuromuscular junction (NMJ) forms centrally in myotubes and, as the only synapse between motor neuron and myotube, are indispensable for motor activity. The midmuscle formation of NMJs, including midmuscle-restricted expression of NMJ-related genes, is governed by the muscle-specific kinase (MuSK). However, mechanisms underlying MuSK-mediated signaling are unclear. Here, we find that the Calcium-binding protein 7 (Cabp7) gene shows midmuscle-restricted expression, and muscle-specific depletion of Cabp7 in mice accelerated age-related NMJ degeneration, muscle weakness/atrophy, and motor dysfunction. Surprisingly, forced expression in muscle of CIP, an inhibitory peptide of the negative regulator of NMJ formation cyclin-dependent kinase 5 (Cdk5), restored NMJ integrity and muscle strength, and healed muscle atrophy in muscle-specific Cabp7-deficient mice, which showed increased muscle expression of the Cdk5 activator p25. These findings together demonstrate that MuSK-mediated signaling induces muscle expression of Cabp7, which suppresses age-related NMJ degeneration likely by attenuating p25 expression, providing insights into prophylactic/therapeutic intervention against age-related motor dysfunction.
Collapse
Affiliation(s)
- Takahiro Eguchi
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Tohru Tezuka
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Yuji Watanabe
- Medical Proteomics Laboratory, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Akane Inoue-Yamauchi
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Hiroshi Sagara
- Medical Proteomics Laboratory, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Manabu Ozawa
- Laboratory of Reproductive Systems Biology, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
- Core Laboratory for Developing Advanced Animal Models, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Yuji Yamanashi
- Division of Genetics, The Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| |
Collapse
|
8
|
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.
Collapse
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
| |
Collapse
|
9
|
Sugimoto T, Sakamaki C, Kimura T, Eguchi T, Miura S, Kamei Y. Peroxisome proliferator-activated receptor γ coactivator 1α regulates downstream of tyrosine kinase-7 (Dok-7) expression important for neuromuscular junction formation. Sci Rep 2024; 14:1780. [PMID: 38245592 PMCID: PMC10799880 DOI: 10.1038/s41598-024-52198-x] [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: 09/03/2023] [Accepted: 01/15/2024] [Indexed: 01/22/2024] Open
Abstract
The neuromuscular junction (NMJ)-formed between a motor nerve terminal and skeletal muscle fiber-plays an important role in muscle contraction and other muscle functions. Aging and neurodegeneration worsen NMJ formation and impair muscle function. Downstream of tyrosine kinase-7 (Dok-7), expressed in skeletal muscle fibers, is essential for the formation of NMJ. Exercise increases the expression of the transcriptional coactivator peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α) in skeletal muscles and restores NMJ formation. In this study, we used skeletal muscle-specific PGC1α knockout or overexpression mice to examine the role of PGC1α in regulating Dok-7 expression and NMJ formation. Our findings revealed that Dok-7 expression is regulated by PGC1α, and luciferase activity of the Dok-7 promoter is greatly increased by coexpressing PGC1α and estrogen receptor-related receptor α. Thus, we suggest PGC1α is involved in exercise-mediated restoration of NMJ formation.
Collapse
Affiliation(s)
- Takumi Sugimoto
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Chihiro Sakamaki
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Tokushi Kimura
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan
| | - Takahiro Eguchi
- Brain-Skeletal Muscle Connection in Aging Project Team, Geroscience Research Center, National Center for Geriatrics and Gerontology, Aichi, Japan
| | - Shinji Miura
- Laboratory of Nutritional Biochemistry, Graduate School of Nutritional and Environmental Sciences, University of Shizuoka, Shizuoka, Japan
| | - Yasutomi Kamei
- Laboratory of Molecular Nutrition, Graduate School of Environmental and Life Science, Kyoto Prefectural University, Kyoto, Japan.
| |
Collapse
|
10
|
Ojeda J, Vergara M, Ávila A, Henríquez JP, Fehlings M, Vidal PM. Impaired communication at the neuromotor axis during Degenerative Cervical Myelopathy. Front Cell Neurosci 2024; 17:1316432. [PMID: 38269114 PMCID: PMC10806149 DOI: 10.3389/fncel.2023.1316432] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Accepted: 12/18/2023] [Indexed: 01/26/2024] Open
Abstract
Degenerative Cervical Myelopathy (DCM) is a progressive neurological condition characterized by structural alterations in the cervical spine, resulting in compression of the spinal cord. While clinical manifestations of DCM are well-documented, numerous unanswered questions persist at the molecular and cellular levels. In this study, we sought to investigate the neuromotor axis during DCM. We use a clinically relevant mouse model, where after 3 months of DCM induction, the sensorimotor tests revealed a significant reduction in both locomotor activity and muscle strength compared to the control group. Immunohistochemical analyses showed alterations in the gross anatomy of the cervical spinal cord segment after DCM. These changes were concomitant with the loss of motoneurons and a decrease in the number of excitatory synaptic inputs within the spinal cord. Additionally, the DCM group exhibited a reduction in the endplate surface, which correlated with diminished presynaptic axon endings in the supraspinous muscles. Furthermore, the biceps brachii (BB) muscle exhibited signs of atrophy and impaired regenerative capacity, which inversely correlated with the transversal area of remnants of muscle fibers. Additionally, metabolic assessments in BB muscle indicated an increased proportion of oxidative skeletal muscle fibers. In line with the link between neuromotor disorders and gut alterations, DCM mice displayed smaller mucin granules in the mucosa layer without damage to the epithelial barrier in the colon. Notably, a shift in the abundance of microbiota phylum profiles reveals an elevated Firmicutes-to-Bacteroidetes ratio-a consistent hallmark of dysbiosis that correlates with alterations in gut microbiota-derived metabolites. Additionally, treatment with short-chain fatty acids stimulated the differentiation of the motoneuron-like NSC34 cell line. These findings shed light on the multifaceted nature of DCM, resembling a synaptopathy that disrupts cellular communication within the neuromotor axis while concurrently exerting influence on other systems. Notably, the colon emerges as a focal point, experiencing substantial perturbations in both mucosal barrier integrity and the delicate balance of intestinal microbiota.
Collapse
Affiliation(s)
- Jorge Ojeda
- Neuroimmunology and Regeneration of the Central Nervous System Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Mayra Vergara
- Neuroimmunology and Regeneration of the Central Nervous System Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Ariel Ávila
- Developmental Neurobiology Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| | - Juan Pablo Henríquez
- Neuromuscular Studies Lab (NeSt Lab), Instituto de Anatomía, Histología y Patología, Facultad de Medicina, Universidad Austral de Chile, Valdivia, Chile
| | - Michael Fehlings
- Department of Genetics and Development, Krembil Research Institute, University Health Network, Toronto, ON, Canada
- Spinal Program, University Health Network, Toronto Western Hospital, Toronto, ON, Canada
| | - Pia M. Vidal
- Neuroimmunology and Regeneration of the Central Nervous System Unit, Biomedical Science Research Laboratory, Basic Sciences Department, Faculty of Medicine, Universidad Católica de la Santísima Concepción, Concepción, Chile
| |
Collapse
|
11
|
Yamaguchi T, Kouzaki K, Sasaki K, Nakazato K. Alterations in neuromuscular junction morphology with ageing and endurance training modulate neuromuscular transmission and myofibre composition. J Physiol 2024. [PMID: 38173183 DOI: 10.1113/jp285143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2023] [Accepted: 12/12/2023] [Indexed: 01/05/2024] Open
Abstract
Both ageing and exercise training affect the neuromuscular junction (NMJ) structure. Morphological alterations in the NMJ have been considered to influence neuromuscular transmission and myofibre properties, but the direct link between the morphology and function has yet to be established. We measured the neuromuscular transmission, myofibre composition and NMJ structure of 5-month-old (young) and 24-month-old untrained (aged control) and trained (aged trained) mice. Aged trained mice were subjected to 2 months of endurance training before the measurement. Neuromuscular transmission was evaluated in vivo as the ratio of ankle plantar flexion torque evoked by the sciatic nerve stimulation to that by direct muscle stimulation. The torque ratio was significantly lower in aged mice than in young and aged trained mice at high-frequency stimulations, showing a significant positive correlation with voluntary grip strength. The degree of pre- to post-synaptic overlap of the NMJ was also significantly lower in aged mice and positively correlated with the torque ratio. We also found that the proportion of fast-twitch fibres in the soleus muscle decreased with age, and that age-related denervation occurred preferentially in fast-twitch fibres. Age-related denervation and a shift in myofibre composition were partially prevented by endurance training. These results suggest that age-related deterioration of the NMJ structure impairs neuromuscular transmission and alters myofibre composition, but these alterations can be prevented by structural amelioration of NMJ with endurance training. Our findings highlight the importance of the NMJ as a major determinant of age-related deterioration of skeletal muscles and the clinical significance of endurance training as a countermeasure. KEY POINTS: The neuromuscular junction (NMJ) plays an essential role in neuromuscular transmission and the maintenance of myofibre properties. We show that neuromuscular transmission is impaired with ageing but recovered by endurance training, which contributes to alterations in voluntary strength. Neuromuscular transmission is associated with the degree of pre- to post-synaptic overlap of the NMJ. Age-related denervation of fast-twitch fibres and a shift in myofibre composition toward a slower phenotype are partially prevented by endurance training. Our study provides substantial evidence that age-related and exercise-induced alterations in neuromuscular transmission and myofibre properties are associated with morphological changes in the NMJ.
Collapse
Affiliation(s)
- Tatsuhiro Yamaguchi
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
- Japan Society for the Promotion of Science, Tokyo, Japan
| | - Karina Kouzaki
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| | - Kazushige Sasaki
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan
| | - Koichi Nakazato
- Graduate School of Health and Sport Science, Nippon Sport Science University, Tokyo, Japan
| |
Collapse
|
12
|
Alava B, Hery G, Sidhom S, Prokop S, Esser K, Abisambra J. Targeted brain-specific tauopathy compromises peripheral skeletal muscle integrity and function. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.17.567586. [PMID: 38014109 PMCID: PMC10680826 DOI: 10.1101/2023.11.17.567586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Tauopathies are neurodegenerative disorders in which the pathological intracellular aggregation of the protein tau causes cognitive deficits. Additionally, clinical studies report muscle weakness in populations with tauopathy. However, whether neuronal pathological tau species confer muscle weakness, and whether skeletal muscle maintains contractile capacity in primary tauopathy remains unknown. Here, we identified skeletal muscle abnormalities in a mouse model of primary tauopathy, expressing human mutant P301L-tau using adeno-associated virus serotype 8 (AAV8). AAV8-P301L mice showed grip strength deficits, hyperactivity, and abnormal histological features of skeletal muscle. Additionally, spatially resolved gene expression of muscle cross sections were altered in AAV8-P301L myofibers. Transcriptional changes showed alterations of genes encoding sarcomeric proteins, proposing a weakness phenotype. Strikingly, specific force of the soleus muscle was blunted in AAV8-P301L tau male mice. Our findings suggest tauopathy has peripheral consequences in skeletal muscle that contribute to weakness in tauopathy.
Collapse
Affiliation(s)
- Bryan Alava
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, 32610, USA
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, Florida, 32610, USA
| | - Gabriela Hery
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, Florida, 32610, USA
| | - Silvana Sidhom
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, 32610, USA
| | - Stefan Prokop
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, Florida, 32610, USA
- Department of Pathology, University of Florida, Gainesville, Florida, 32610, USA
| | - Karyn Esser
- Department of Physiology and Aging, University of Florida, Gainesville, Florida, 32610, USA
| | - Jose Abisambra
- Center for Translational Research in Neurodegenerative Disease (CTRND), University of Florida, Gainesville, Florida, 32610, USA
- Department of Neuroscience, University of Florida, Gainesville, Florida, 32610, USA
- Brain Injury Rehabilitation and Neuroresilience (BRAIN) Center, University of Florida, Gainesville, Florida, 32601, USA
| |
Collapse
|
13
|
Hastings RL, Avila MF, Suneby E, Juros D, O'Young A, Peres da Silva J, Valdez G. Cellular and molecular evidence that synaptic Schwann cells contribute to aging of mouse neuromuscular junctions. Aging Cell 2023; 22:e13981. [PMID: 37771191 PMCID: PMC10652323 DOI: 10.1111/acel.13981] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 09/30/2023] Open
Abstract
Age-induced degeneration of the neuromuscular junction (NMJ) is associated with motor dysfunction and muscle atrophy. While the impact of aging on the NMJ presynapse and postsynapse is well-documented, little is known about the changes perisynaptic Schwann cells (PSCs), the synaptic glia of the NMJ, undergo during aging. Here, we examined PSCs in young, middle-aged, and old mice in three muscles with different susceptibility to aging. Using light and electron microscopy, we found that PSCs acquire age-associated cellular features either prior to or at the same time as the onset of NMJ degeneration. Notably, we found that aged PSCs fail to completely cap the NMJ even though they are more abundant in old compared with young mice. We also found that aging PSCs form processes that either intrude into the synaptic cleft or guide axonal sprouts to innervate other NMJs. We next profiled the transcriptome of PSCs and other Schwann cells (SCs) to identify mechanisms altered in aged PSCs. This analysis revealed that aged PSCs acquire a transcriptional pattern previously shown to promote phagocytosis that is absent in other SCs. It also showed that aged PSCs upregulate unique pro-inflammatory molecules compared to other aged SCs. Interestingly, neither synaptogenesis genes nor genes that are typically upregulated by repair SCs were induced in aged PSCs or other SCs. These findings provide insights into cellular and molecular mechanisms that could be targeted in PSCs to stave off the deleterious effects of aging on NMJs.
Collapse
Affiliation(s)
- Robert Louis Hastings
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | | | - Emma Suneby
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Devin Juros
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Anson O'Young
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Jason Peres da Silva
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science, and Center on the Biology of Aging, Brown University, Providence, Rhode Island, USA
| |
Collapse
|
14
|
Fish LA, Ewing MD, Jaime D, Rich KA, Xi C, Wang X, Feder RE, Wharton KA, Rich MM, Arnold WD, Fallon JR. The MuSK-BMP pathway regulates synaptic Nav1.4 localization and muscle excitability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.24.563837. [PMID: 37961580 PMCID: PMC10634800 DOI: 10.1101/2023.10.24.563837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
The neuromuscular junction (NMJ) is the linchpin of nerve-evoked muscle contraction. Broadly considered, the function of the NMJ is to transduce a nerve action potential into a muscle fiber action potential (MFAP). Efficient information transfer requires both cholinergic signaling, responsible for the generation of endplate potentials (EPPs), and excitation, the activation of postsynaptic voltage-gated sodium channels (Nav1.4) to trigger MFAPs. In contrast to the cholinergic apparatus, the signaling pathways that organize Nav1.4 and muscle fiber excitability are poorly characterized. Muscle-specific kinase (MuSK), in addition to its Ig1 domain-dependent role as an agrin-LRP4 receptor, is also a BMP co-receptor that binds BMPs via its Ig3 domain and shapes BMP-induced signaling and transcriptional output. Here we probed the function of the MuSK-BMP pathway at the NMJ using mice lacking the MuSK Ig3 domain ('ΔIg3-MuSK'). Synapses formed normally in ΔIg3-MuSK animals, but the postsynaptic apparatus was fragmented from the first weeks of life. Anatomical denervation was not observed at any age examined. Moreover, spontaneous and nerve-evoked acetylcholine release, AChR density, and endplate currents were comparable to WT. However, trains of nerve-evoked MFAPs in ΔIg3-MuSK muscle were abnormal as revealed by increased jitter and blocking in single fiber electromyography. Further, nerve-evoked compound muscle action potentials (CMAPs), as well as twitch and tetanic muscle torque force production, were also diminished. Finally, Nav1.4 levels were reduced at ΔIg3-MuSK synapses but not at the extrajunctional sarcolemma, indicating that the observed excitability defects are the result of impaired localization of this voltage-gated ion channel at the NMJ. We propose that MuSK plays two distinct roles at the NMJ: as an agrin-LRP4 receptor necessary for establishing and maintaining cholinergic signaling, and as a BMP co-receptor required for maintaining proper Nav1.4 density, nerve-evoked muscle excitability and force production. The MuSK-BMP pathway thus emerges as a target for modulating excitability and functional innervation, which are defective in conditions such as congenital myasthenic syndromes and aging.
Collapse
Affiliation(s)
- L. A. Fish
- Neuroscience Graduate Program, Brown University, Providence, RI 02912
- Carney Institute for Brain Science, Brown University, Providence, RI 02912
| | - M. D. Ewing
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - D. Jaime
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - K. A. Rich
- Neuroscience Graduate Program, Ohio State University, Columbus, OH 43210
| | - C. Xi
- Biotechnology Graduate Program, Brown University, Brown University, Providence, RI 02912
| | - X. Wang
- Department of Neuroscience Cell Biology and Physiology, Wright State University, Dayton, OH 45435
| | - R. E. Feder
- Department of Neuroscience, Brown University, Providence, RI 02912
| | - K. A. Wharton
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02912
| | - M. M. Rich
- Department of Neuroscience Cell Biology and Physiology, Wright State University, Dayton, OH 45435
| | - W. D. Arnold
- NextGen Precision Health Institute, University of Missouri, Columbia, MO 62511
| | - J. R. Fallon
- Carney Institute for Brain Science, Brown University, Providence, RI 02912
- Department of Neuroscience, Brown University, Providence, RI 02912
| |
Collapse
|
15
|
Catanese A, Rajkumar S, Sommer D, Masrori P, Hersmus N, Van Damme P, Witzel S, Ludolph A, Ho R, Boeckers TM, Mulaw M. Multiomics and machine-learning identify novel transcriptional and mutational signatures in amyotrophic lateral sclerosis. Brain 2023; 146:3770-3782. [PMID: 36883643 PMCID: PMC10473564 DOI: 10.1093/brain/awad075] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Revised: 02/15/2023] [Accepted: 02/25/2023] [Indexed: 03/09/2023] Open
Abstract
Amyotrophic lateral sclerosis is a fatal and incurable neurodegenerative disease that mainly affects the neurons of the motor system. Despite the increasing understanding of its genetic components, their biological meanings are still poorly understood. Indeed, it is still not clear to which extent the pathological features associated with amyotrophic lateral sclerosis are commonly shared by the different genes causally linked to this disorder. To address this point, we combined multiomics analysis covering the transcriptional, epigenetic and mutational aspects of heterogenous human induced pluripotent stem cell-derived C9orf72-, TARDBP-, SOD1- and FUS-mutant motor neurons as well as datasets from patients' biopsies. We identified a common signature, converging towards increased stress and synaptic abnormalities, which reflects a unifying transcriptional program in amyotrophic lateral sclerosis despite the specific profiles due to the underlying pathogenic gene. In addition, whole genome bisulphite sequencing linked the altered gene expression observed in mutant cells to their methylation profile, highlighting deep epigenetic alterations as part of the abnormal transcriptional signatures linked to amyotrophic lateral sclerosis. We then applied multi-layer deep machine-learning to integrate publicly available blood and spinal cord transcriptomes and found a statistically significant correlation between their top predictor gene sets, which were significantly enriched in toll-like receptor signalling. Notably, the overrepresentation of this biological term also correlated with the transcriptional signature identified in mutant human induced pluripotent stem cell-derived motor neurons, highlighting novel insights into amyotrophic lateral sclerosis marker genes in a tissue-independent manner. Finally, using whole genome sequencing in combination with deep learning, we generated the first mutational signature for amyotrophic lateral sclerosis and defined a specific genomic profile for this disease, which is significantly correlated to ageing signatures, hinting at age as a major player in amyotrophic lateral sclerosis. This work describes innovative methodological approaches for the identification of disease signatures through the combination of multiomics analysis and provides novel knowledge on the pathological convergencies defining amyotrophic lateral sclerosis.
Collapse
Affiliation(s)
- Alberto Catanese
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, 89081 Ulm, Germany
- Translational Protein Biochemistry, German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
| | - Sandeep Rajkumar
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, 89081 Ulm, Germany
| | - Daniel Sommer
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, 89081 Ulm, Germany
| | - Pegah Masrori
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, 3000 Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, 3000 Leuven, Belgium
- Experimental Neurology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Nicole Hersmus
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, 3000 Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, 3000 Leuven, Belgium
- Experimental Neurology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Philip Van Damme
- Laboratory of Neurobiology, Center for Brain & Disease Research, VIB, 3000 Leuven, Belgium
- Department of Neurology, University Hospitals Leuven, 3000 Leuven, Belgium
- Experimental Neurology, Department of Neurosciences, Leuven Brain Institute, KU Leuven, 3000 Leuven, Belgium
| | - Simon Witzel
- Department of Neurology, Ulm University School of Medicine, 89081 Ulm, Germany
| | - Albert Ludolph
- Translational Protein Biochemistry, German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
- Department of Neurology, Ulm University School of Medicine, 89081 Ulm, Germany
| | - Ritchie Ho
- Center for Neural Science and Medicine, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Board of Governors Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Neurology, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Tobias M Boeckers
- Institute of Anatomy and Cell Biology, Ulm University School of Medicine, 89081 Ulm, Germany
- Translational Protein Biochemistry, German Center for Neurodegenerative Diseases (DZNE), Ulm site, 89081 Ulm, Germany
| | - Medhanie Mulaw
- Unit for Single-Cell Genomics, Medical Faculty, Ulm University, 89081 Ulm, Germany
| |
Collapse
|
16
|
Johnson LL, Hebert S, Kueppers RB, McLoon LK. Nystagmus Associated With the Absence of MYOD Expression Across the Lifespan in Extraocular and Limb Muscles. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 37703038 PMCID: PMC10503593 DOI: 10.1167/iovs.64.12.24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 08/18/2023] [Indexed: 09/14/2023] Open
Abstract
Purpose The extraocular muscles (EOMs) undergo significant levels of continuous myonuclear turnover and myofiber remodeling throughout life, in contrast to limb skeletal muscles. Activation of the myogenic pathway in muscle precursor cells is controlled by myogenic transcription factors, such as MYOD. Limb muscles from MyoD-/- mice develop normally but have a regeneration defect, and these mice develop nystagmus. We examined MyoD-/- mice to determine if they have an aging phenotype. Methods Eye movements of aging MyoD-/- mice and littermate controls (wild type) were examined using optokinetic nystagmus (OKN). We assessed limb muscle function, changes to myofiber number, mean cross-sectional area, and abundance of the PAX7 and PITX2 populations of myogenic precursor cells. Results Aging did not significantly affect limb muscle function despite decreased mean cross-sectional areas at 18+ months. Aging wild type mice had normal OKN responses; all aging MyoD-/- mice had nystagmus. With OKN stimulus present, the MyoD-/- mice at all ages had shorter slow phase durations compared to wild type age matched controls. In the dark, the MyoD-/- mice had a shorter slow phase duration with age. This correlated with significantly decreased fiber numbers and cross-sectional areas. The EOM in MyoD-/- mice had increased numbers of PAX7-positive satellite cells and significantly decreased PITX2-positive myonuclei. Conclusions The absence of MYOD expression in aging mice causes a decrease in on-going myofiber remodeling, EOM fiber size, and number, and is associated with the development of spontaneous nystagmus. These results suggest that muscle-specific mutations can result in nystagmus, with increasing aging-related changes in the MyoD-/- EOM.
Collapse
Affiliation(s)
- Laura L. Johnson
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
| | - Sadie Hebert
- Department of Biology Teaching and Learning, University of Minnesota, Minneapolis, Minnesota, United States
| | - Rachel B. Kueppers
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
| | - Linda K. McLoon
- Department of Ophthalmology and Visual Neurosciences, University of Minnesota, Minneapolis, Minnesota, United States
- Graduate Program in Molecular, Cellular, Developmental Biology and Genetics, University of Minnesota, Minneapolis, Minnesota, United States
- Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, United States
| |
Collapse
|
17
|
Dungan CM, Wells JM, Murach KA. The life and times of cellular senescence in skeletal muscle: friend or foe for homeostasis and adaptation? Am J Physiol Cell Physiol 2023; 325:C324-C331. [PMID: 37335024 PMCID: PMC10393344 DOI: 10.1152/ajpcell.00553.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 06/08/2023] [Accepted: 06/08/2023] [Indexed: 06/21/2023]
Abstract
A gradual decline in skeletal muscle mass and function is closely tied to increased mortality and disease risk during organismal aging. Exercise training is the most effective way to enhance muscle health, but the adaptive response to exercise as well as muscle repair potential is blunted in older individuals. Numerous mechanisms contribute to the loss of muscle mass and plasticity as aging progresses. An emerging body of recent evidence implicates an accumulation of senescent ("zombie") cells in muscle as a contributing factor to the aging phenotype. Senescent cells cannot divide but can release inflammatory factors and create an unfavorable environment for homeostasis and adaptation. On balance, some evidence indicates that cells with senescent characteristics can be beneficial for the muscle adaptive process, specifically at younger ages. Emerging evidence also suggests that multinuclear muscle fibers could become senescent. In this review, we summarize current literature on the prevalence of senescent cells in skeletal muscle and highlight the consequences of senescent cell removal on muscle mass, function, and adaptability. We examine key limitations in the field of senescence specifically in skeletal muscle and identify areas of research that require future investigation.NEW & NOTEWORTHY There is evidence to suggest that senescent "zombie" cells may or may not accrue in aging skeletal muscle. When muscle is perturbed regardless of age, senescent-like cells do appear, and the benefits of removing them could be age-dependent. More work is needed to determine the magnitude of accumulation and source of senescent cells in muscle. Regardless, pharmacological senolytic treatment of aged muscle is beneficial for adaptation.
Collapse
Affiliation(s)
- Cory M Dungan
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, Texas, United States
| | - Jaden M Wells
- Department of Health, Human Performance, and Recreation, Baylor University, Waco, Texas, United States
| | - Kevin A Murach
- Department of Health, Human Performance, and Recreation, University of Arkansas, Fayetteville, Arkansas, United States
| |
Collapse
|
18
|
Paul TA, Macpherson PC, Janetzke TL, Davis CS, Jackson MJ, McArdle A, Brooks SV. Older mice show decreased regeneration of neuromuscular junctions following lengthening contraction-induced injury. GeroScience 2023; 45:1899-1912. [PMID: 36952126 PMCID: PMC10400502 DOI: 10.1007/s11357-023-00774-w] [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: 11/11/2022] [Accepted: 03/13/2023] [Indexed: 03/24/2023] Open
Abstract
Progressive muscle atrophy and loss of muscle strength associated with old age have been well documented. Although age-associated impairments in skeletal muscle regeneration following injury have been demonstrated, less is known about whether aging impacts the regenerative response of neuromuscular junctions (NMJ) following contraction-induced injury. Reduced ability of NMJs to regenerate could lead to increased numbers of denervated muscle fibers and therefore play a contributing role to age-related sarcopenia. To investigate the relationship between age and NMJ regeneration following injury, extensor digitorum longus (EDL) muscles of middle-aged (18-19 months) and old mice (27-28 months) were subjected to a protocol of lengthening contractions (LC) that resulted in an acute force deficit of ~55% as well as functional and histological evidence of a similar magnitude of injury 3 days post LCs that was not different between age groups. After 28 days, the architecture and innervation of the NMJs were evaluated. The numbers of fragmented endplates increased and of fully innervated NMJs decreased post-injury for the muscle of both middle-aged and old mice and for contralateral uninjured muscles of old compared with uninjured muscles of middle-aged controls. Thus, the diminished ability of the skeletal muscle of old mice to recover following injury may be due in part to an age-related decrease in the ability to regenerate NMJs in injured muscles. The impaired ability to regenerate NMJs may be a triggering factor for degenerative changes at the NMJ contributing to muscle fiber weakness and loss in old age.
Collapse
Affiliation(s)
- Thomas A. Paul
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
- Department of Biomedical Engineering, University of Michigan, 2029 Biomedical Sciences Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
| | - Peter C. Macpherson
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Tara L. Janetzke
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Carol S. Davis
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
| | - Malcolm J. Jackson
- MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Life Course and Ageing Science, University of Liverpool, Liverpool, UK
| | - Anne McArdle
- MRC-Versus Arthritis Centre for Integrated Research into Musculoskeletal Ageing (CIMA), Institute of Life Course and Ageing Science, University of Liverpool, Liverpool, UK
| | - Susan V. Brooks
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI USA
- Department of Biomedical Engineering, University of Michigan, 2029 Biomedical Sciences Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200 USA
| |
Collapse
|
19
|
Castro RW, Lopes MC, Settlage RE, Valdez G. Aging alters mechanisms underlying voluntary movements in spinal motor neurons of mice, primates, and humans. JCI Insight 2023; 8:e168448. [PMID: 37154159 PMCID: PMC10243831 DOI: 10.1172/jci.insight.168448] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/15/2023] [Indexed: 05/10/2023] Open
Abstract
Spinal motor neurons have been implicated in the loss of motor function that occurs with advancing age. However, the cellular and molecular mechanisms that impair the function of these neurons during aging remain unknown. Here, we show that motor neurons do not die in old female and male mice, rhesus monkeys, and humans. Instead, these neurons selectively and progressively shed excitatory synaptic inputs throughout the soma and dendritic arbor during aging. Thus, aged motor neurons contain a motor circuitry with a reduced ratio of excitatory to inhibitory synapses that may be responsible for the diminished ability to activate motor neurons to commence movements. An examination of the motor neuron translatome (ribosomal transcripts) in male and female mice reveals genes and molecular pathways with roles in glia-mediated synaptic pruning, inflammation, axonal regeneration, and oxidative stress that are upregulated in aged motor neurons. Some of these genes and pathways are also found altered in motor neurons affected with amyotrophic lateral sclerosis (ALS) and responding to axotomy, demonstrating that aged motor neurons are under significant stress. Our findings show mechanisms altered in aged motor neurons that could serve as therapeutic targets to preserve motor function during aging.
Collapse
Affiliation(s)
- Ryan W. Castro
- Neuroscience Graduate Program
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
| | - Mikayla C. Lopes
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
- Molecular Biology, Cell Biology, and Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Robert E. Settlage
- Department of Advanced Research Computing, Virginia Tech, Blacksburg, Virginia, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cellular Biology, and Biochemistry
- Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, and
- Department of Neurology, Warren Alpert Medical School of Brown University, Providence, Rhode Island, USA
| |
Collapse
|
20
|
Use of a novel technique to assess impact of age-related denervation on mouse soleus muscle function. Biogerontology 2023; 24:377-390. [PMID: 36790689 PMCID: PMC10147802 DOI: 10.1007/s10522-023-10021-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2022] [Accepted: 01/26/2023] [Indexed: 02/16/2023]
Abstract
Denervation contributes to loss of force-generating capacity in aged skeletal muscles, but problems with quantification of denervated fibers mean the precise impact of denervation on muscle function remains unclear. This study therefore looked to develop a reliable assay for identifying denervated muscle fibers, and used this to explore the impact of denervation on age-related force-generation in mouse skeletal muscle. Thirteen young (6-month-old) and 10 old (24-months-old) C57Bl/6 J female mice were utilized. Anaesthetized mice were infused with the fluorescent deoxyglucose analog 2[N-(7-nitrobenz-2-oxa-1,2-diaxol-4-yl)amino]-2-deoxyglucose (2-NBDG) and the tibial nerve was repeatedly stimulated to label active skeletal muscle fibers by activity-dependent uptake of 2-NBDG. Data on muscle force generation were acquired as part of the stimulation routine. Labeled muscles were removed, snap frozen, sectioned, and slide mounted. Sections were imaged to show accumulation of 2-NBDG in activated fibers and lack of 2-NBDG accumulation in quiescent (denervated) fibers, then processed using immunohistochemistry to allow collection of data on fiber number and morphology. Soleus muscles from older mice had nine times as many denervated fibers as those from young mice (average n = 36 vs 4, old vs young). Older muscles developed significantly more passive force and less specific force, but denervation only partly accounted for age-related deficits in specific force. Further investigations are required to definitively identify contributors to the decrease in force generation that remain unaccounted for.
Collapse
|
21
|
Badiola-Mateos M, Osaki T, Kamm RD, Samitier J. In vitro modelling of human proprioceptive sensory neurons in the neuromuscular system. Sci Rep 2022; 12:21318. [PMID: 36494423 PMCID: PMC9734133 DOI: 10.1038/s41598-022-23565-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 11/02/2022] [Indexed: 12/13/2022] Open
Abstract
Proprioceptive sensory neurons (pSN) are an essential and undervalued part of the neuromuscular circuit. A protocol to differentiate healthy and amyotrophic lateral sclerosis (ALS) human neural stem cells (hNSC) into pSN, and their comparison with the motor neuron (MN) differentiation process from the same hNSC sources, facilitated the development of in vitro co-culture platforms. The obtained pSN spheroids cultured interact with human skeletal myocytes showing the formation of annulospiral wrapping-like structures between TrkC + neurons and a multinucleated muscle fibre, presenting synaptic bouton-like structures in the contact point. The comparative analysis of the genetic profile performed in healthy and sporadic ALS hNSC differentiated to pSN suggested that basal levels of ETV1, critical for motor feedback from pSN, were much lower for ALS samples and that the differences between healthy and ALS samples, suggest the involvement of pSN in ALS pathology development and progression.
Collapse
Affiliation(s)
- Maider Badiola-Mateos
- grid.424736.00000 0004 0536 2369Institute for Bioengineering of Catalonia (IBEC)—Barcelona Institute of Science and Technology, 08028 Barcelona, Spain ,grid.5841.80000 0004 1937 0247Department of Electronic and Biomedical Engineering, Universitat de Barcelona, 08028 Barcelona, Spain ,grid.116068.80000 0001 2341 2786Department of Biological Engineering, Massachusetts Institute of Technology (MIT), 500 Technology Square, MIT Building, Cambridge, MA 02139 USA ,grid.263145.70000 0004 1762 600XPresent Address: The BioRobotics Institute, Department of Excellence in Robotics and AI, Scuola Superiore Sant’Anna, 56127 Pisa, Italy
| | - Tatsuya Osaki
- grid.116068.80000 0001 2341 2786Department of Biological Engineering, Massachusetts Institute of Technology (MIT), 500 Technology Square, MIT Building, Cambridge, MA 02139 USA ,grid.26999.3d0000 0001 2151 536XPresent Address: Institute of Industrial Science, The University of Tokyo, 4-6-1, Komaba, Meguro-Ku, Tokyo, 153-8505 Japan
| | - Roger Dale Kamm
- grid.116068.80000 0001 2341 2786Department of Biological Engineering, Massachusetts Institute of Technology (MIT), 500 Technology Square, MIT Building, Cambridge, MA 02139 USA ,grid.116068.80000 0001 2341 2786Department of Mechanical Engineering, Massachusetts Institute of Technology, 500 Technology Square, MIT Building, Cambridge, MA 02139 USA
| | - Josep Samitier
- grid.424736.00000 0004 0536 2369Institute for Bioengineering of Catalonia (IBEC)—Barcelona Institute of Science and Technology, 08028 Barcelona, Spain ,grid.5841.80000 0004 1937 0247Department of Electronic and Biomedical Engineering, Universitat de Barcelona, 08028 Barcelona, Spain ,grid.512890.7Centro de Investigación Biomédica en Red (CIBER-BBN), 28029 Madrid, Spain
| |
Collapse
|
22
|
Cardiac troponin T and autoimmunity in skeletal muscle aging. GeroScience 2022; 44:2025-2045. [PMID: 35034279 PMCID: PMC9616986 DOI: 10.1007/s11357-022-00513-7] [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: 09/02/2021] [Accepted: 01/05/2022] [Indexed: 01/03/2023] Open
Abstract
Age-related muscle mass and strength decline (sarcopenia) impairs the performance of daily living activities and can lead to mobility disability/limitation in older adults. Biological pathways in muscle that lead to mobility problems have not been fully elucidated. Immunoglobulin G (IgG) infiltration in muscle is a known marker of increased fiber membrane permeability and damage vulnerability, but whether this translates to impaired function is unknown. Here, we report that IgG1 and IgG4 are abundantly present in the skeletal muscle (vastus lateralis) of ~ 50% (11 out of 23) of older adults (> 65 years) examined. Skeletal muscle IgG1 was inversely correlated with physical performance (400 m walk time: r = 0.74, p = 0.005; SPPB score: r = - 0.73, p = 0.006) and muscle strength (r = - 0.6, p = 0.05). In a murine model, IgG was found to be higher in both muscle and blood of older, versus younger, C57BL/6 mice. Older mice with a higher level of muscle IgG had lower motor activity. IgG in mouse muscle co-localized with cardiac troponin T (cTnT) and markers of complement activation and apoptosis/necroptosis. Skeletal muscle-inducible cTnT knockin mice also showed elevated IgG in muscle and an accelerated muscle degeneration and motor activity decline with age. Most importantly, anti-cTnT autoantibodies were detected in the blood of cTnT knockin mice, old mice, and older humans. Our findings suggest a novel cTnT-mediated autoimmune response may be an indicator of sarcopenia.
Collapse
|
23
|
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.
Collapse
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.
| |
Collapse
|
24
|
Coleman MP. Axon Biology in ALS: Mechanisms of Axon Degeneration and Prospects for Therapy. Neurotherapeutics 2022; 19:1133-1144. [PMID: 36207571 PMCID: PMC9587191 DOI: 10.1007/s13311-022-01297-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2022] [Indexed: 10/10/2022] Open
Abstract
This review addresses the longstanding debate over whether amyotrophic lateral sclerosis (ALS) is a 'dying back' or 'dying forward' disorder in the light of new gene identifications and the increased understanding of mechanisms of action for previously identified ALS genes. While the topological pattern of pathology in animal models, and more anecdotally in patients is indeed 'dying back', this review discusses how this fits with the fact that many of the major initiating events are thought to occur within the soma. It also discusses how widely varying ALS risk factors, including some impacting axons directly, may combine to drive a common pathway involving TAR DNA binding protein 43 (TDP-43) and neuromuscular junction (NMJ) denervation. The emerging association between sterile alpha and TIR motif-containing 1 (SARM1), a protein so far mostly associated with axon degeneration, and sporadic ALS is another major theme. The strengths and limitations of the current evidence supporting an association are considered, along with ways in which SARM1 could become activated in ALS. The final section addresses SARM1-based therapies along with the prospects for targeting other axonal steps in ALS pathogenesis.
Collapse
Affiliation(s)
- Michael P Coleman
- John van Geest Centre for Brain Repair, Department of Clinical Neurosciences, University of Cambridge, Robinson Way, Cambridge, CB2 0PY, UK.
| |
Collapse
|
25
|
Lee PJ, Kennedy Z, Wang Y, Lu Y, Cefaliello C, Uyan Ö, Song C, Godinho BMDC, Xu Z, Rusckowski M, Xue W, Brown RH. Imaging Net Retrograde Axonal Transport In Vivo: A Physiological Biomarker. Ann Neurol 2022; 91:716-729. [PMID: 35178738 PMCID: PMC9313858 DOI: 10.1002/ana.26329] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/06/2022] [Accepted: 02/14/2022] [Indexed: 11/26/2022]
Abstract
OBJECTIVE The objective of this study is to develop a novel method for monitoring the integrity of motor neurons in vivo by quantifying net retrograde axonal transport. METHODS The method uses single photon emission computed tomography to quantify retrograde transport to spinal cord of tetanus toxin fragment C (125 I-TTC) following intramuscular injection. We characterized the transport profiles in 3 transgenic mouse models carrying amyotrophic lateral sclerosis (ALS)-associated genes, aging mice, and SOD1G93A transgenic mice following CRISPR/Cas9 gene editing. Lastly, we studied the effect of prior immunization of tetanus toxoid on the transport profile of TTC. RESULTS This technique defines a quantitative profile of net retrograde axonal transport of TTC in living mice. The profile is distinctly abnormal in transgenic SOD1G93A mice as young as 65 days (presymptomatic) and worsens with disease progression. Moreover, this method detects a distinct therapeutic benefit of gene editing in transgenic SOD1G93A mice well before other clinical parameters (eg, grip strength) show improvement. Symptomatic transgenic PFN1C71G/C71G ALS mice display gross reductions in net retrograde axonal transport, which is also disturbed in asymptomatic mice harboring a human C9ORF72 transgene with an expanded GGGGCC repeat motif. In wild-type mice, net retrograde axonal transport declines with aging. Lastly, prior immunization with tetanus toxoid does not preclude use of this assay. INTERPRETATION This assay of net retrograde axonal transport has broad potential clinical applications and should be particularly valuable as a physiological biomarker that permits early detection of benefit from potential therapies for motor neuron diseases. ANN NEUROL 2022;91:716-729.
Collapse
Affiliation(s)
- Pin‐Tsun Justin Lee
- Department of NeurologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Zachary Kennedy
- Department of NeurologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA,RNA Therapeutics InstituteUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Yuzhen Wang
- Department of RadiologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | | | - Carolina Cefaliello
- Department of NeurologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Özgün Uyan
- Department of NeurologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Chun‐Qing Song
- RNA Therapeutics InstituteUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA,Program in Molecular Medicine, Department of Molecular, Cell, and Cancer Biology, and Li Weibo Institute for Rare Disease ResearchUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Bruno Miguel da Cruz Godinho
- RNA Therapeutics InstituteUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA,Program in Molecular Medicine, Department of Molecular, Cell, and Cancer Biology, and Li Weibo Institute for Rare Disease ResearchUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Zuoshang Xu
- Department of Biochemistry and Molecular PharmacologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Mary Rusckowski
- Department of RadiologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Wen Xue
- RNA Therapeutics InstituteUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA,Program in Molecular Medicine, Department of Molecular, Cell, and Cancer Biology, and Li Weibo Institute for Rare Disease ResearchUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| | - Robert H. Brown
- Department of NeurologyUniversity of Massachusetts Chan Medical SchoolWorcesterMAUSA
| |
Collapse
|
26
|
Bannow LI, Bonaterra GA, Bertoune M, Maus S, Schulz R, Weissmann N, Kraut S, Kinscherf R, Hildebrandt W. Effect of chronic intermittent hypoxia (CIH) on neuromuscular junctions and mitochondria in slow- and fast-twitch skeletal muscles of mice—the role of iNOS. Skelet Muscle 2022; 12:6. [PMID: 35151349 PMCID: PMC8841105 DOI: 10.1186/s13395-022-00288-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 01/10/2022] [Indexed: 01/17/2023] Open
Abstract
Background Obstructive sleep apnea (OSA) imposes vascular and metabolic risks through chronic intermittent hypoxia (CIH) and impairs skeletal muscle performance. As studies addressing limb muscles are rare, the reasons for the lower exercise capacity are unknown. We hypothesize that CIH-related morphological alterations in neuromuscular junctions (NMJ) and mitochondrial integrity might be the cause of functional disorders in skeletal muscles. Methods Mice were kept under 6 weeks of CIH (alternating 7% and 21% O2 fractions every 30 s, 8 h/day, 5 days/week) compared to normoxia (NOX). Analyses included neuromuscular junctions (NMJ) postsynaptic morphology and integrity, fiber cross-sectional area (CSA) and composition (ATPase), mitochondrial ultrastructure (transmission-electron-microscopy), and relevant transcripts (RT-qPCR). Besides wildtype (WT), we included inducible nitric oxide synthase knockout mice (iNOS−/−) to evaluate whether iNOS is protective or risk-mediating. Results In WT soleus muscle, CIH vs. NOX reduced NMJ size (− 37.0%, p < 0.001) and length (− 25.0%, p < 0.05) together with fiber CSA of type IIa fibers (− 14%, p < 0.05) and increased centronucleated fiber fraction (p < 0.001). Moreover, CIH vs. NOX increased the fraction of damaged mitochondria (1.8-fold, p < 0.001). Compared to WT, iNOS−/− similarly decreased NMJ area and length with NOX (− 55%, p < 0.001 and − 33%, p < 0.05, respectively) or with CIH (− 37%, p < 0.05 and − 29%, p < 0.05), however, prompted no fiber atrophy. Moreover, increased fractions of damaged (2.1-fold, p < 0.001) or swollen (> 6-fold, p < 0.001) mitochondria were observed with iNOS−/− vs. WT under NOX and similarly under CIH. Both, CIH- and iNOS−/− massively upregulated suppressor-of-cytokine-signaling-3 (SOCS3) > 10-fold without changes in IL6 mRNA expression. Furthermore, inflammatory markers like CD68 (macrophages) and IL1β were significantly lower in CIH vs. NOX. None of these morphological alterations with CIH- or iNOS−/− were detected in the gastrocnemius muscle. Notably, iNOS expression was undetectable in WT muscle, unlike the liver, where it was massively decreased with CIH. Conclusion CIH leads to NMJ and mitochondrial damage associated with fiber atrophy/centronucleation selectively in slow-twitch muscle of WT. This effect is largely mimicked by iNOS−/− at NOX (except for atrophy). Both conditions involve massive SOCS3 upregulation likely through denervation without Il6 upregulation but accompanied by a decrease of macrophage density especially next to denervated endplates. In the absence of muscular iNOS expression in WT, this damage may arise from extramuscular, e.g., motoneuronal iNOS deficiency (through CIH or knockout) awaiting functional evaluation. Supplementary Information The online version contains supplementary material available at 10.1186/s13395-022-00288-7.
Collapse
|
27
|
Massopust R, Juros D, Shapiro D, Lopes M, Haldar SM, Taetzsch T, Valdez G. KLF15 overexpression in myocytes fails to ameliorate ALS-related pathology or extend the lifespan of SOD1G93A mice. Neurobiol Dis 2022; 162:105583. [PMID: 34902552 PMCID: PMC8750438 DOI: 10.1016/j.nbd.2021.105583] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 11/19/2021] [Accepted: 12/10/2021] [Indexed: 01/22/2023] Open
Abstract
Amyotrophic Lateral Sclerosis (ALS) is a currently incurable disease that causes progressive motor neuron loss, paralysis and death. Skeletal muscle pathology occurs early during the course of ALS. It is characterized by impaired mitochondrial biogenesis, metabolic dysfunction and deterioration of the neuromuscular junction (NMJ), the synapse through which motor neurons communicate with muscles. Therefore, a better understanding of the molecules that underlie this pathology may lead to therapies that slow motor neuron loss and delay ALS progression. Kruppel Like Factor 15 (KLF15) has been identified as a transcription factor that activates alternative metabolic pathways and NMJ maintenance factors, including Fibroblast Growth Factor Binding Protein 1 (FGFBP1), in skeletal myocytes. In this capacity, KLF15 has been shown to play a protective role in Duchenne muscular dystrophy (DMD) and spinal muscular atrophy (SMA), however its role in ALS has not been evaluated. Here, we examined whether muscle-specific KLF15 overexpression promotes the health of skeletal muscles and NMJs in the SOD1G93A ALS mouse model. We show that muscle-specific KLF15 overexpression did not elicit a significant beneficial effect on skeletal muscle atrophy, NMJ health, motor function, or survival in SOD1G93A ALS mice. Our findings suggest that, unlike in mouse models of DMD and SMA, KLF15 overexpression has a minimal impact on ALS disease progression in SOD1G93A mice.
Collapse
Affiliation(s)
- Ryan Massopust
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Devin Juros
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Dillon Shapiro
- Molecular Biology, Cell Biology, & Biochemistry Graduate Program, Brown University, Providence, Rhode Island, USA
| | - Mikayla Lopes
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Saptarsi M. Haldar
- Gladstone Institutes, San Francisco, California, USA,Department of Medicine, Cardiology Division, UCSF School of Medicine, San Francisco, California, USA,Current address: Amgen Research, South San Francisco, California, USA
| | - Thomas Taetzsch
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Gregorio Valdez
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, Rhode Island, USA,Center for Translational Neuroscience, Robert J. and Nancy D. Carney Institute for Brain Science and Brown Institute for Translational Science, Brown University, Providence, Rhode Island, USA,Department of Neurology, Warren Alpert Medical School of Brown University, Providence, United States
| |
Collapse
|
28
|
Burke SK, Fenton AI, Konokhova Y, Hepple RT. Variation in muscle and neuromuscular junction morphology between atrophy-resistant and atrophy-prone muscles supports failed re-innervation in aging muscle atrophy. Exp Gerontol 2021; 156:111613. [PMID: 34740815 DOI: 10.1016/j.exger.2021.111613] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/24/2021] [Accepted: 10/21/2021] [Indexed: 10/19/2022]
Abstract
In advanced age, there is an accelerated decline in skeletal muscle mass that appears to be secondary to repeated cycles of denervation-reinnervation and eventually, failed reinnervation. However, whether variation in reinnervation capacity explains why some muscles are less vulnerable to age-related atrophy has not been addressed. In this study we examined changes in neuromuscular junction (NMJ) morphology, fiber cross-sectional area (CSA) and fiber type, accumulation of severely atrophied myofibers, and expression of a marker of denervation in four muscles that exhibit differences in the degree of age-related atrophy and which span the extremes of fiber type composition in 8 mo old (8 M) and 34 mo old (34 M) male Fischer 344 Brown Norway F1 hybrid rats. Aging muscle atrophy was most pronounced in the fast twitch gastrocnemius (Gas; 25%) and similar between extensor digitorum longus (EDL) and slow-twitch soleus (Sol) muscle (14-15%), whereas the slow-twitch adductor longus (AL) increased in mass by 21% between 8 M and 34 M (P < 0.05 for all). Only the Sol exhibited significant alterations in fiber type with aging, and there was a decrease in fiber CSA in the Gas, EDL, and Sol (P < 0.05) with aging that was not seen in the AL. Muscles that atrophied had an increased fraction of severely atrophic myofibers (P < 0.05), but this was not observed in the AL. The Gas and EDL both demonstrated a similar degree of age-related remodeling of pre- and post-synaptic NMJ components. On the other hand, pre- and post-synaptic morphology underwent greater changes with aging in the AL, and many of these same morphological variables were already greater in the Sol vs AL at 8 M, suggesting the Sol had already undergone substantial remodeling and may be nearing its adaptive limits. Consistent with this idea, analysis of NMJ morphology in Sol from 3 M rats exhibited similar values as 8 M AL, and the Sol demonstrated greater expression of the denervation marker neural cell adhesion molecule (NCAM) compared to the AL at 34 M. Collectively, our results are consistent with NMJ remodeling capacity being finite with aging and that maintained remodeling potential confers atrophy protection in aging skeletal muscle by reducing the degree of persistent denervation.
Collapse
Affiliation(s)
- Sarah K Burke
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Andrew I Fenton
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA
| | - Yana Konokhova
- Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Russell T Hepple
- Department of Physical Therapy, College of Public Health and Health Professions, University of Florida, Gainesville, FL, USA.
| |
Collapse
|
29
|
Wells TL, Myles JR, Akay T. C-Boutons and Their Influence on Amyotrophic Lateral Sclerosis Disease Progression. J Neurosci 2021; 41:8088-8101. [PMID: 34380764 PMCID: PMC8460137 DOI: 10.1523/jneurosci.0660-21.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 07/29/2021] [Accepted: 08/04/2021] [Indexed: 11/21/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is an adult-onset neurodegenerative disease with progressive motor neuron death, where patients usually die within 5 years of diagnosis. Previously, we showed that the C-boutons, which are large cholinergic synapses to motor neurons that modulate motor neuron activity, are necessary for behavioral compensation in mSOD1G93A mice, a mouse model for ALS. We reasoned that, since the C-boutons likely increase the excitability of surviving motor neurons to compensate for motor neuron loss during ALS disease progression, then amplitude modulation through the C-boutons likely increases motor neuron stress and worsens disease progression. By comparing male and female mSOD1G93A mice to mSOD1G93A mice with genetically silenced C-boutons [mSOD1G93A ; Dbx1::cre; ChATfl/fl (mSOD1G93A/Coff )], we show that the C-boutons do not influence the humane end point of mSOD1G93A mice; however, our histologic analysis shows that C-bouton silencing significantly improves fast-twitch muscle innervation over time. Using immunohistology, we also show that the C-boutons are active in a task-dependent manner, and that symptomatic mSOD1G93A mice show significantly higher C-bouton activity than wild-type mice during low-intensity walking. Last, by using behavioral analysis, we provide evidence that C-bouton silencing in combination with swimming is beneficial for the behavioral capabilities of mSOD1G93A mice. Our observations suggest that manipulating the C-boutons in combination with a modulatory-targeted training program may therefore be beneficial for ALS patients and could result in improved mobility and quality of life.SIGNIFICANCE STATEMENT Despite decades of research on amyotrophic lateral sclerosis (ALS), there have been little improvements in treatments and therapies. We sought to better understand how the activation of C-boutons, which are large cholinergic modulatory synapses on motor neurons, change and affect the disease as it progresses. When these C-boutons are genetically silenced and exercises designed to otherwise activate the C-boutons are frequently performed in ALS model mice, the mice perform better than their untreated counterparts over time. C-bouton-targeted therapies could therefore be beneficial for ALS patients and could result in improved mobility and quality of life.
Collapse
Affiliation(s)
- Tyler L Wells
- Atlantic Mobility Action Project, Brain Repair Center, Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 0A8, Canada
| | - Jacob R Myles
- Atlantic Mobility Action Project, Brain Repair Center, Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 0A8, Canada
| | - Turgay Akay
- Atlantic Mobility Action Project, Brain Repair Center, Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 0A8, Canada
| |
Collapse
|
30
|
Maimon R, Ankol L, Gradus Pery T, Altman T, Ionescu A, Weissova R, Ostrovsky M, Tank E, Alexandra G, Shelestovich N, Opatowsky Y, Dori A, Barmada S, Balastik M, Perlson E. A CRMP4-dependent retrograde axon-to-soma death signal in amyotrophic lateral sclerosis. EMBO J 2021; 40:e107586. [PMID: 34190355 PMCID: PMC8408612 DOI: 10.15252/embj.2020107586] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 05/11/2021] [Accepted: 05/28/2021] [Indexed: 12/13/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal non-cell-autonomous neurodegenerative disease characterized by the loss of motor neurons (MNs). Mutations in CRMP4 are associated with ALS in patients, and elevated levels of CRMP4 are suggested to affect MN health in the SOD1G93A -ALS mouse model. However, the mechanism by which CRMP4 mediates toxicity in ALS MNs is poorly understood. Here, by using tissue from human patients with sporadic ALS, MNs derived from C9orf72-mutant patients, and the SOD1G93A -ALS mouse model, we demonstrate that subcellular changes in CRMP4 levels promote MN loss in ALS. First, we show that while expression of CRMP4 protein is increased in cell bodies of ALS-affected MN, CRMP4 levels are decreased in the distal axons. Cellular mislocalization of CRMP4 is caused by increased interaction with the retrograde motor protein, dynein, which mediates CRMP4 transport from distal axons to the soma and thereby promotes MN loss. Blocking the CRMP4-dynein interaction reduces MN loss in human-derived MNs (C9orf72) and in ALS model mice. Thus, we demonstrate a novel CRMP4-dependent retrograde death signal that underlies MN loss in ALS.
Collapse
Affiliation(s)
- Roy Maimon
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Lior Ankol
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
| | - Tal Gradus Pery
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Topaz Altman
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Ariel Ionescu
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
| | - Romana Weissova
- Institue of Physiology of the Czech Academy of SciencesPragueCzech Republic
- Faculty of ScienceCharles UniversityPragueCzech Republic
| | | | - Elizabeth Tank
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Gayster Alexandra
- Department of PathologySheba Medical CenterTel HashomerRamat GanIsrael
| | - Natalia Shelestovich
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Department of PathologySheba Medical CenterTel HashomerRamat GanIsrael
| | - Yarden Opatowsky
- The Mina and Everard Goodman Faculty of Life ScienceBar Ilan UniversityIsrael
| | - Amir Dori
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
- Department of NeurologySheba Medical CenterTel HashomerRamat GanIsrael
| | - Sami Barmada
- Department of NeurologyUniversity of MichiganAnn ArborMIUSA
| | - Martin Balastik
- Institue of Physiology of the Czech Academy of SciencesPragueCzech Republic
| | - Eran Perlson
- Sackler Faculty of MedicineTel Aviv UniversityTel AvivIsrael
- Sagol School of NeuroscienceTel Aviv UniversityTel AvivIsrael
| |
Collapse
|
31
|
Pratt J, De Vito G, Narici M, Boreham C. Neuromuscular Junction Aging: A Role for Biomarkers and Exercise. J Gerontol A Biol Sci Med Sci 2021; 76:576-585. [PMID: 32832976 DOI: 10.1093/gerona/glaa207] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related skeletal muscle degradation known as "sarcopenia" exerts considerable strain on public health systems globally. While the pathogenesis of such atrophy is undoubtedly multifactorial, disruption at the neuromuscular junction (NMJ) has recently gained traction as a key explanatory factor. The NMJ, an essential communicatory link between nerve and muscle, undergoes profound changes with advancing age. Ascertaining whether such changes potentiate the onset of sarcopenia would be paramount in facilitating a timely implementation of targeted therapeutic strategies. Hence, there is a growing level of importance to further substantiate the effects of age on NMJs, in parallel with developing measures to attenuate such changes. As such, this review aimed to establish the current standpoint on age-related NMJ deterioration and consequences for skeletal muscle, while illuminating a role for biomarkers and exercise in ameliorating these alterations. Recent insights into the importance of key biomarkers for NMJ stability are provided, while the stimulative benefits of exercise in preserving NMJ function are demonstrated. Further elucidation of the diagnostic and prognostic relevance of biomarkers, coupled with the therapeutic benefits of regular exercise may be crucial in combating age-related NMJ and skeletal muscle degradation.
Collapse
Affiliation(s)
- Jedd Pratt
- Institute for Sport and Health, University College Dublin, Ireland.,Genuity Science, Dublin, Ireland
| | - Giuseppe De Vito
- Department of Biomedical Sciences, CIR-Myo Myology Centre, Neuromuscular Physiology Laboratory, University of Padua, Italy
| | - Marco Narici
- Department of Biomedical Sciences, CIR-Myo Myology Centre, Neuromuscular Physiology Laboratory, University of Padua, Italy
| | - Colin Boreham
- Institute for Sport and Health, University College Dublin, Ireland
| |
Collapse
|
32
|
Gras S, Blasco A, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Rueda R, Pereira SL, Navarro X, Esquerda JE, Calderó J. Beneficial effects of dietary supplementation with green tea catechins and cocoa flavanols on aging-related regressive changes in the mouse neuromuscular system. Aging (Albany NY) 2021; 13:18051-18093. [PMID: 34319911 PMCID: PMC8351677 DOI: 10.18632/aging.203336] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 06/19/2021] [Indexed: 12/17/2022]
Abstract
Besides skeletal muscle wasting, sarcopenia entails morphological and molecular changes in distinct components of the neuromuscular system, including spinal cord motoneurons (MNs) and neuromuscular junctions (NMJs); moreover, noticeable microgliosis has also been observed around aged MNs. Here we examined the impact of two flavonoid-enriched diets containing either green tea extract (GTE) catechins or cocoa flavanols on age-associated regressive changes in the neuromuscular system of C57BL/6J mice. Compared to control mice, GTE- and cocoa-supplementation significantly improved the survival rate of mice, reduced the proportion of fibers with lipofuscin aggregates and central nuclei, and increased the density of satellite cells in skeletal muscles. Additionally, both supplements significantly augmented the number of innervated NMJs and their degree of maturity compared to controls. GTE, but not cocoa, prominently increased the density of VAChT and VGluT2 afferent synapses on MNs, which were lost in control aged spinal cords; conversely, cocoa, but not GTE, significantly augmented the proportion of VGluT1 afferent synapses on aged MNs. Moreover, GTE, but not cocoa, reduced aging-associated microgliosis and increased the proportion of neuroprotective microglial phenotypes. Our data indicate that certain plant flavonoids may be beneficial in the nutritional management of age-related deterioration of the neuromuscular system.
Collapse
Affiliation(s)
- Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Alejandro Barranco
- Department of Biochemistry and Molecular Biology II, School of Pharmacy, University of Granada, Granada, Spain
| | - Tapas Das
- Abbott Nutrition, Research and Development, Columbus, OH 43215, USA
| | - Ricardo Rueda
- Abbott Nutrition, Research and Development, Granada, Spain
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cellular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona and CIBERNED, Bellaterra, Spain
| | - Josep E. Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida and Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| |
Collapse
|
33
|
Sugita S, Tamura K, Yano M, Minegishi Y, Ota N. The Impact of Milk Fat Globule Membrane with Exercise on Age-Related Degeneration of Neuromuscular Junctions. Nutrients 2021; 13:nu13072310. [PMID: 34371820 PMCID: PMC8308682 DOI: 10.3390/nu13072310] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 06/28/2021] [Accepted: 06/30/2021] [Indexed: 12/19/2022] Open
Abstract
Morphological changes in neuromuscular junctions (NMJs), which are synapses formed between α-motor neurons and skeletal muscle fibers, are considered to be important in age-related motor dysfunction. We have previously shown that the intake of dietary milk fat globule membrane (MFGM) combined with exercise attenuates age-related NMJ alterations in the early phase of aging. However, it is unclear whether the effect of MFGM with exercise on age-related NMJ alterations persists into old age, and whether intervention from old age is still effective when age-related changes in NMJs have already occurred. In this study, 6- or 18-month-old mice were treated with a 1% MFGM diet and daily running wheel exercise until 23 or 24 months of age, respectively. MFGM treatment with exercise was effective in suppressing the progression of age-related NMJ alterations in old age, and even after age-related changes in NMJs had already occurred. Moreover, the effect of MFGM intake with exercise was not restricted to NMJs but extended to the structure and function of peripheral nerves. This study demonstrates that MFGM intake with exercise may be a novel approach for improving motor function in the elderly by suppressing age-related NMJ alterations.
Collapse
|
34
|
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.
Collapse
|
35
|
Padilla CJ, Harrigan ME, Harris H, Schwab JM, Rutkove SB, Rich MM, Clark BC, Arnold WD. Profiling age-related muscle weakness and wasting: neuromuscular junction transmission as a driver of age-related physical decline. GeroScience 2021; 43:1265-1281. [PMID: 33895959 PMCID: PMC8190265 DOI: 10.1007/s11357-021-00369-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022] Open
Abstract
Pathological age-related loss of skeletal muscle strength and mass contribute to impaired physical function in older adults. Factors that promote the development of these conditions remain incompletely understood, impeding development of effective and specific diagnostic and therapeutic approaches. Inconclusive evidence across species suggests disruption of action potential signal transmission at the neuromuscular junction (NMJ), the crucial connection between the nervous and muscular systems, as a possible contributor to age-related muscle dysfunction. Here we investigated age-related loss of NMJ function using clinically relevant, electrophysiological measures (single-fiber electromyography (SFEMG) and repetitive nerve stimulation (RNS)) in aged (26 months) versus young (6 months) F344 rats. Measures of muscle function (e.g., grip strength, peak plantarflexion contractility torque) and mass were assessed for correlations with physiological measures (e.g., indices of NMJ transmission). Other outcomes also included plantarflexion muscle contractility tetanic torque fade during 1-s trains of stimulation as well as gastrocnemius motor unit size and number. Profiling NMJ function in aged rats identified significant declines in NMJ transmission stability and reliability. Further, NMJ deficits were tightly correlated with hindlimb grip strength, gastrocnemius muscle weight, loss of peak contractility torque, degree of tetanic fade, and motor unit loss. Thus, these findings provide direct evidence for NMJ dysfunction as a potential mechanism of age-related muscle dysfunction pathogenesis and severity. These findings also suggest that NMJ transmission modulation may serve as a target for therapeutic development for age-related loss of physical function.
Collapse
Affiliation(s)
- Carlos J Padilla
- Division of Neuromuscular Diseases, Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Room 207, Columbus, OH, 43210, USA
| | - Markus E Harrigan
- Division of Neuromuscular Diseases, Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Room 207, Columbus, OH, 43210, USA
| | - Hallie Harris
- Division of Neuromuscular Diseases, Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Room 207, Columbus, OH, 43210, USA
| | - Jan M Schwab
- Division of Neuromuscular Diseases, Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Room 207, Columbus, OH, 43210, USA
- Belford Center for Spinal Cord Injury, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Center for Brain and Spinal Cord Repair, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- The Neurological Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA
| | - Seward B Rutkove
- Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Mark M Rich
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, OH, 45435, USA
| | - Brian C Clark
- Department of Biomedical Sciences, Ohio Musculoskeletal and Neurological Institute, Athens, OH, 45701, USA
| | - W David Arnold
- Division of Neuromuscular Diseases, Department of Neurology, The Ohio State University Wexner Medical Center, 1060 Carmack Road, Room 207, Columbus, OH, 43210, USA.
- Department of Physical Medicine and Rehabilitation, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- The Neurological Institute, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
- Department of Physiology and Cell Biology, The Ohio State University Wexner Medical Center, Columbus, OH, USA.
| |
Collapse
|
36
|
Abstract
PURPOSE OF REVIEW This review encompasses the main novelties regarding nonimmune mechanisms implicated in the pathogenesis of idiopathic inflammatory myopathies (IIM). RECENT FINDINGS In recent years, growing data support a role for endoplasmic-reticulum (ER) stress as a propagator of muscular damage, together with the release of interferon type I and reactive oxygen species in hypoxemic muscle fibers. Other studies evaluating the relationship between autophagy and Toll-like receptors (TLRs) in IIM subtypes have shown increased TLR3 and TLR4 expression in fibers of IIM patients and colocalization with LC3, an autophagy marker, submitting autophagy as a likely player in IIM pathogenesis. Most novel evidences concern the potential role of denervation of the neuromuscular junction in IIM, possibly connected to hyperexpression of MHC-I, and trafficking of extracellular vesicles, which may represent a connection between nonimmune and immune-mediated mechanisms of muscle inflammation and damage. SUMMARY Nonimmune mechanisms contribute to the pathogenesis of IIM, likely cooperating with immune-mediated inflammation. Consistent data were released for ER stress, autophagy, mitochondrial dysfunction and hypoxia; in addition to, neuromuscular denervation and extracellular vesicles have been proposed as thoughtful links between muscle inflammation, damage and atrophy. Further understanding of nonimmune abnormalities and potential reversible pathways is needed to improve the management of IIM.
Collapse
|
37
|
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.
Collapse
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
| |
Collapse
|
38
|
Fuertes-Alvarez S, Izeta A. Terminal Schwann Cell Aging: Implications for Age-Associated Neuromuscular Dysfunction. Aging Dis 2021; 12:494-514. [PMID: 33815879 PMCID: PMC7990373 DOI: 10.14336/ad.2020.0708] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 07/08/2020] [Indexed: 12/11/2022] Open
Abstract
Action potential is transmitted to muscle fibers through specialized synaptic interfaces called neuromuscular junctions (NMJs). These structures are capped by terminal Schwann cells (tSCs), which play essential roles during formation and maintenance of the NMJ. tSCs are implicated in the correct communication between nerves and muscles, and in reinnervation upon injury. During aging, loss of muscle mass and strength (sarcopenia and dynapenia) are due, at least in part, to the progressive loss of contacts between muscle fibers and nerves. Despite the important role of tSCs in NMJ function, very little is known on their implication in the NMJ-aging process and in age-associated denervation. This review summarizes the current knowledge about the implication of tSCs in the age-associated degeneration of NMJs. We also speculate on the possible mechanisms underlying the observed phenotypes.
Collapse
Affiliation(s)
- Sandra Fuertes-Alvarez
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain
| | - Ander Izeta
- 1Biodonostia, Tissue Engineering Group, Paseo Dr. Begiristain, s/n, San Sebastian 20014, Spain.,2Tecnun-University of Navarra, School of Engineering, Department of Biomedical Engineering and Science, Paseo Mikeletegi, 48, San Sebastian 20009, Spain
| |
Collapse
|
39
|
Zakyrjanova GF, Giniatullin AR, Mukhutdinova KA, Kuznetsova EA, Petrov AM. Early differences in membrane properties at the neuromuscular junctions of ALS model mice: Effects of 25-hydroxycholesterol. Life Sci 2021; 273:119300. [PMID: 33662433 DOI: 10.1016/j.lfs.2021.119300] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2020] [Revised: 02/13/2021] [Accepted: 02/25/2021] [Indexed: 12/11/2022]
Abstract
AIMS Plasma hyperlipidemia is a protective factor in amyotrophic lateral sclerosis (ALS) while cholesterol-lowering drugs aggravate the pathology. We hypothesize that this phenomenon can be linked with membrane lipid alterations in the neuromuscular junctions (NMJs) occurring before motor neuron loss. METHODS Neurotransmitter release in parallel with lipid membrane properties in diaphragm NMJs of SOD1G93A (mSOD) mice at nine weeks of age (pre-onset stage) were assessed. KEY FINDINGS Despite on slight changes in spontaneous and evoked quantum release of acetylcholine, extracellular levels of choline at resting conditions, an indicator of non-quantum release, were significantly increased in mSOD mice. The use of lipid-sensitive fluorescent probes points to lipid raft disruption in the NMJs of mSOD mice. However, content of cholesterol, a key raft component was unchanged implying another pathway responsible for the loss of raft integrity. In the mSOD mice we found marked increase in levels of raft-destabilizing lipid ceramide. This was accompanied by enhanced ability to uptake of exogenous ceramide in NMJs. Acute and chronic administration of 25-hydroxycholesterol, whose levels increase due to hypercholesterolemia, recovered early alterations in membrane properties. Furthermore, chronic treatment with 25-hydroxycholesterol prevented increase in ceramide and extracellular choline levels as well as suppressed lipid peroxidation of NMJ membranes and fragmentation of end plates. SIGNIFICANCE Thus, lipid raft disruption likely due to ceramide accumulation could be early event in ALS which may trigger neuromuscular abnormalities. Cholesterol derivative 25-hydroxycholesterol may serve as a molecule restoring the membrane and functional properties of NMJs at the early stage.
Collapse
Affiliation(s)
- Guzel F Zakyrjanova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
| | - Arthur R Giniatullin
- Department of Normal Physiology, Kazan State Medial University, 49 Butlerova Street, Kazan 420012, Russia
| | - Kamilla A Mukhutdinova
- Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia
| | - Eva A Kuznetsova
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia
| | - Alexey M Petrov
- Laboratory of Biophysics of Synaptic Processes, Kazan Institute of Biochemistry and Biophysics, Federal Research Center "Kazan Scientific Center of RAS", 2/31 Lobachevsky Street, box 30, Kazan 420111, Russia; Institute of Neuroscience, Kazan State Medial University, 49 Butlerova Street, Kazan, 420012, Russia.
| |
Collapse
|
40
|
Neuroprotective Effect of Vascular Endothelial Growth Factor on Motoneurons of the Oculomotor System. Int J Mol Sci 2021; 22:ijms22020814. [PMID: 33467517 PMCID: PMC7830098 DOI: 10.3390/ijms22020814] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 01/04/2023] Open
Abstract
Vascular endothelial growth factor (VEGF) was initially characterized as a potent angiogenic factor based on its activity on the vascular system. However, it is now well established that VEGF also plays a crucial role as a neuroprotective factor in the nervous system. A deficit of VEGF has been related to motoneuronal degeneration, such as that occurring in amyotrophic lateral sclerosis (ALS). Strikingly, motoneurons of the oculomotor system show lesser vulnerability to neurodegeneration in ALS compared to other motoneurons. These motoneurons presented higher amounts of VEGF and its receptor Flk-1 than other brainstem pools. That higher VEGF level could be due to an enhanced retrograde input from their target muscles, but it can also be produced by the motoneurons themselves and act in an autocrine way. By contrast, VEGF’s paracrine supply from the vicinity cells, such as glial cells, seems to represent a minor source of VEGF for brainstem motoneurons. In addition, ocular motoneurons experiment an increase in VEGF and Flk-1 level in response to axotomy, not observed in facial or hypoglossal motoneurons. Therefore, in this review, we summarize the differences in VEGF availability that could contribute to the higher resistance of extraocular motoneurons to injury and neurodegenerative diseases.
Collapse
|
41
|
Tu WY, Xu W, Zhang K, Shen C. Whole-mount staining of neuromuscular junctions in adult mouse diaphragms with a sandwich-like apparatus. J Neurosci Methods 2020; 350:109016. [PMID: 33316317 DOI: 10.1016/j.jneumeth.2020.109016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 11/22/2020] [Accepted: 11/26/2020] [Indexed: 12/11/2022]
Abstract
BACKGROUND Investigation of neuromuscular junction (NMJ) morphology by immunochemistry can provide important insights into the physiological and pathological status of neuromuscular disorders. Sectioning and muscle fiber tearing are commonly required to prepare experimentally accessible samples, while muscles that are flat and thin can be investigated with whole-mount immunohistochemistry for a comprehensive overview of the entire innervation pattern. The diaphragm is important for respiratory function and one of the flat muscles frequently used for studying neuromuscular development as well as neuromuscular pathology. Nevertheless, techniques for reliable whole-mount immunolabeling of adult diaphragms are lacking, mainly due to the poor tissue permeability of labeling reagents. An effective approach for researchers to be able to comprehensively visualize and characterize NMJ defects of the adult diaphragm in mouse models is therefore of clear importance. NEW METHOD This protocol demonstrates that the diaphragm can be thinned and spread out under even pressure using two Perspex boards for better whole-mount immunostaining. RESULTS The expanded mouse diaphragm allows the comprehensive assessment of a number of NMJ phenotypes. COMPARISON WITH EXISTING METHODS Most peer-reviewed and online protocols can be applied to the embryonic diaphragm but fail to show the entire innervation pattern in the adult diaphragm. Our method provides a convenient approach and present a clear innervation pattern that increases the reliability of the assessment of NMJ phenotypes in the diaphragm. CONCLUSIONS This simple method for whole-mount immunostaining of the adult diaphragm will allow researchers to perform a detailed analysis of the neuromuscular system in mouse models.
Collapse
Affiliation(s)
- Wen-Yo Tu
- Department of Neurobiology, The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China.
| | - Wentao Xu
- Department of Neurobiology, The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China
| | - Kejing Zhang
- Department of Neurobiology, The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China
| | - Chengyong Shen
- Department of Neurobiology, The First Affiliated Hospital, Institute of Translational Medicine, School of Medicine, Zhejiang University, Zhejiang, China; Department of Neurobiology, Key Laboratory of Medical Neurobiology of Zhejiang Province, School of Medicine, Zhejiang University, Zhejiang, China.
| |
Collapse
|
42
|
Blasco A, Gras S, Mòdol-Caballero G, Tarabal O, Casanovas A, Piedrafita L, Barranco A, Das T, Pereira SL, Navarro X, Rueda R, Esquerda JE, Calderó J. Motoneuron deafferentation and gliosis occur in association with neuromuscular regressive changes during ageing in mice. J Cachexia Sarcopenia Muscle 2020; 11:1628-1660. [PMID: 32691534 PMCID: PMC7749545 DOI: 10.1002/jcsm.12599] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 06/05/2020] [Accepted: 06/15/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND The cellular mechanisms underlying the age-associated loss of muscle mass and function (sarcopenia) are poorly understood, hampering the development of effective treatment strategies. Here, we performed a detailed characterization of age-related pathophysiological changes in the mouse neuromuscular system. METHODS Young, adult, middle-aged, and old (1, 4, 14, and 24-30 months old, respectively) C57BL/6J mice were used. Motor behavioural and electrophysiological tests and histological and immunocytochemical procedures were carried out to simultaneously analyse structural, molecular, and functional age-related changes in distinct cellular components of the neuromuscular system. RESULTS Ageing was not accompanied by a significant loss of spinal motoneurons (MNs), although a proportion (~15%) of them in old mice exhibited an abnormally dark appearance. Dark MNs were also observed in adult (~9%) and young (~4%) animals, suggesting that during ageing, some MNs undergo early deleterious changes, which may not lead to MN death. Old MNs were depleted of cholinergic and glutamatergic inputs (~40% and ~45%, respectively, P < 0.01), suggestive of age-associated alterations in MN excitability. Prominent microgliosis and astrogliosis [~93% (P < 0.001) and ~100% (P < 0.0001) increase vs. adults, respectively] were found in old spinal cords, with increased density of pro-inflammatory M1 microglia and A1 astroglia (25-fold and 4-fold increase, respectively, P < 0.0001). Ageing resulted in significant reductions in the nerve conduction velocity and the compound muscle action potential amplitude (~30%, P < 0.05, vs. adults) in old distal plantar muscles. Compared with adult muscles, old muscles exhibited significantly higher numbers of both denervated and polyinnervated neuromuscular junctions, changes in fibre type composition, higher proportion of fibres showing central nuclei and lipofuscin aggregates, depletion of satellite cells, and augmented expression of different molecules related to development, plasticity, and maintenance of neuromuscular junctions, including calcitonin gene-related peptide, growth associated protein 43, agrin, fibroblast growth factor binding protein 1, and transforming growth factor-β1. Overall, these alterations occurred at varying degrees in all the muscles analysed, with no correlation between the age-related changes observed and myofiber type composition or muscle topography. CONCLUSIONS Our data provide a global view of age-associated neuromuscular changes in a mouse model of ageing and help to advance understanding of contributing pathways leading to development of sarcopenia.
Collapse
Affiliation(s)
- Alba Blasco
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Sílvia Gras
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Guillem Mòdol-Caballero
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Olga Tarabal
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Anna Casanovas
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Lídia Piedrafita
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | | | - Tapas Das
- Abbott Nutrition Research and Development, Columbus, OH, USA
| | | | - Xavier Navarro
- Grup de Neuroplasticitat i Regeneració, Institut de Neurociències, Departament de Biologia Cel·lular, Fisiologia i Immunologia, Universitat Autònoma de Barcelona, CIBERNED, Bellaterra, Spain
| | - Ricardo Rueda
- Abbott Nutrition Research and Development, Granada, Spain
| | - Josep E Esquerda
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| | - Jordi Calderó
- Unitat de Neurobiologia Cel·lular, Departament de Medicina Experimental, Facultat de Medicina, Universitat de Lleida, Institut de Recerca Biomèdica de Lleida (IRBLleida), Lleida, Spain
| |
Collapse
|
43
|
Jørgensen HS, Jensen DB, Dimintiyanova KP, Bonnevie VS, Hedegaard A, Lehnhoff J, Moldovan M, Grondahl L, Meehan CF. Increased Axon Initial Segment Length Results in Increased Na + Currents in Spinal Motoneurones at Symptom Onset in the G127X SOD1 Mouse Model of Amyotrophic Lateral Sclerosis. Neuroscience 2020; 468:247-264. [PMID: 33246068 DOI: 10.1016/j.neuroscience.2020.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 10/22/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease preferentially affecting motoneurones. Transgenic mouse models have been used to investigate the role of abnormal motoneurone excitability in this disease. Whilst an increased excitability has repeatedly been demonstrated in vitro in neonatal and embryonic preparations from SOD1 mouse models, the results from the only studies to record in vivo from spinal motoneurones in adult SOD1 models have produced conflicting findings. Deficits in repetitive firing have been reported in G93A SOD1(high copy number) mice but not in presymptomatic G127X SOD1 mice despite shorter motoneurone axon initial segments (AISs) in these mice. These discrepancies may be due to the earlier disease onset and prolonged disease progression in G93A SOD1 mice with recordings potentially performed at a later sub-clinical stage of the disease in this mouse. To test this, and to explore how the evolution of excitability changes with symptom onset we performed in vivo intracellular recording and AIS labelling in G127X SOD1 mice immediately after symptom onset. No reductions in repetitive firing were observed showing that this is not a common feature across all ALS models. Immunohistochemistry for the Na+ channel Nav1.6 showed that motoneurone AISs increase in length in G127X SOD1 mice at symptom onset. Consistent with this, the rate of rise of AIS components of antidromic action potentials were significantly faster confirming that this increase in length represents an increase in AIS Na+ channels occurring at symptom onset in this model.
Collapse
Affiliation(s)
- H S Jørgensen
- Department of Neuroscience, University of Copenhagen, Denmark
| | - D B Jensen
- Department of Neuroscience, University of Copenhagen, Denmark
| | | | - V S Bonnevie
- Department of Neuroscience, University of Copenhagen, Denmark
| | - A Hedegaard
- Department of Neuroscience, University of Copenhagen, Denmark
| | - J Lehnhoff
- Department of Neuroscience, University of Copenhagen, Denmark
| | - M Moldovan
- Department of Neuroscience, University of Copenhagen, Denmark
| | - L Grondahl
- Department of Neuroscience, University of Copenhagen, Denmark
| | - C F Meehan
- Department of Neuroscience, University of Copenhagen, Denmark.
| |
Collapse
|
44
|
Badawi Y, Nishimune H. Impairment Mechanisms and Intervention Approaches for Aged Human Neuromuscular Junctions. Front Mol Neurosci 2020; 13:568426. [PMID: 33328881 PMCID: PMC7717980 DOI: 10.3389/fnmol.2020.568426] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/16/2020] [Indexed: 12/19/2022] Open
Abstract
The neuromuscular junction (NMJ) is a chemical synapse formed between a presynaptic motor neuron and a postsynaptic muscle cell. NMJs in most vertebrate species share many essential features; however, some differences distinguish human NMJs from others. This review will describe the pre- and postsynaptic structures of human NMJs and compare them to NMJs of laboratory animals. We will focus on age-dependent declines in function and changes in the structure of human NMJs. Furthermore, we will describe insights into the aging process revealed from mouse models of accelerated aging. In addition, we will compare aging phenotypes to other human pathologies that cause impairments of pre- and postsynaptic structures at NMJs. Finally, we will discuss potential intervention approaches for attenuating age-related NMJ dysfunction and sarcopenia in humans.
Collapse
Affiliation(s)
- Yomna Badawi
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, United States
| | - Hiroshi Nishimune
- Department of Anatomy and Cell Biology, University of Kansas School of Medicine, Kansas City, KS, United States.,Neurobiology of Aging, Tokyo Metropolitan Institute of Gerontology, Itabashi, Japan
| |
Collapse
|
45
|
Colín E, Ramírez-Jarquín UN, Tapia R. Early motor deficits in the phalangeal fine movements induced by chronic AMPA infusion in the rat spinal cord assessed by a novel method: Phalangeal tension recording test. Neurosci Lett 2020; 739:135411. [PMID: 33086093 DOI: 10.1016/j.neulet.2020.135411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2020] [Revised: 09/02/2020] [Accepted: 09/24/2020] [Indexed: 11/20/2022]
Abstract
Motor behavior alterations are a shared hallmark of neurodegenerative diseases affecting motor circuits, such as amyotrophic lateral sclerosis (ALS), Parkinson's, and Huntington's diseases. In patients and transgenic animal models of amyotrophic lateral sclerosis fine movements controlled by distal muscles are the first to be affected, but its study and knowledge remain poorly understood, mainly because most of the tests used for describing the motor alterations are focused on the function of proximal muscles and gross movements. In this study we demonstrate that alterations of phalangeal fine movements can be quantitatively evaluated using a novel procedure designed by us, phalangeal tension recording test, which showed high sensitivity to detect such alterations. The evaluation was carried out during the motor neuron (MN) degenerative process induced by the acute and chronic overactivation of AMPA receptors in the lumbar rat spinal cord, using previously described models. The new method allowed the quantification of significant alterations of the fine movements of the hindpaws phalanges when AMPA was infused in the lumbar segment controlling the distal muscles, but not when a more rostral spinal segment was infused, and these alterations were not detected by the rotarod or the stride tests. These changes occurred before the paralysis of the hindlimbs. Studying the early distal motor alterations before the total paralysis at late stages is essential for understanding the initial consequences of MN degeneration and therefore for designing new strategies for the control, treatment and prevention of MN diseases.
Collapse
Affiliation(s)
- Elizabeth Colín
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Uri Nimrod Ramírez-Jarquín
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico
| | - Ricardo Tapia
- División de Neurociencias, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, 04510, Ciudad de México, Mexico.
| |
Collapse
|
46
|
Bhaskaran S, Pollock N, C. Macpherson P, Ahn B, Piekarz KM, Staunton CA, Brown JL, Qaisar R, Vasilaki A, Richardson A, McArdle A, Jackson MJ, Brooks SV, Van Remmen H. Neuron-specific deletion of CuZnSOD leads to an advanced sarcopenic phenotype in older mice. Aging Cell 2020; 19:e13225. [PMID: 32886862 PMCID: PMC7576239 DOI: 10.1111/acel.13225] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 07/01/2020] [Accepted: 07/26/2020] [Indexed: 01/21/2023] Open
Abstract
Age-associated loss of muscle mass and function (sarcopenia) has a profound effect on the quality of life in the elderly. Our previous studies show that CuZnSOD deletion in mice (Sod1-/- mice) recapitulates sarcopenia phenotypes, including elevated oxidative stress and accelerated muscle atrophy, weakness, and disruption of neuromuscular junctions (NMJs). To determine whether deletion of Sod1 initiated in neurons in adult mice is sufficient to induce muscle atrophy, we treated young (2- to 4-month-old) Sod1flox/SlickHCre mice with tamoxifen to generate i-mn-Sod1KO mice. CuZnSOD protein was 40-50% lower in neuronal tissue in i-mn-Sod1KO mice. Motor neuron number in ventral spinal cord was reduced 28% at 10 months and more than 50% in 18- to 22-month-old i-mn-Sod1KO mice. By 24 months, 22% of NMJs in i-mn-Sod1KO mice displayed a complete lack of innervation and deficits in specific force that are partially reversed by direct muscle stimulation, supporting the loss of NMJ structure and function. Muscle mass was significantly reduced by 16 months of age and further decreased at 24 months of age. Overall, our findings show that neuronal-specific deletion of CuZnSOD is sufficient to cause motor neuron loss in young mice, but that NMJ disruption, muscle atrophy, and weakness are not evident until past middle age. These results suggest that loss of innervation is critical but may not be sufficient until the muscle reaches a threshold beyond which it cannot compensate for neuronal loss or rescue additional fibers past the maximum size of the motor unit.
Collapse
Affiliation(s)
- Shylesh Bhaskaran
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Natalie Pollock
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseMRC‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA)University of LiverpoolLiverpoolUK
| | - Peter C. Macpherson
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborMIUSA
| | - Bumsoo Ahn
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Katarzyna M. Piekarz
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
- Oklahoma Center For NeuroscienceUniversity of Oklahoma Health Sciences CenterOklahoma CityOKUSA
| | - Caroline A. Staunton
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseMRC‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA)University of LiverpoolLiverpoolUK
| | - Jacob L. Brown
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Rizwan Qaisar
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
| | - Aphrodite Vasilaki
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseMRC‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA)University of LiverpoolLiverpoolUK
| | - Arlan Richardson
- Oklahoma City VA Medical CenterOklahoma CityOKUSA
- Department of Biochemistry and Molecular BiologyUniversity of Oklahoma Health Sciences CenterOklahoma CityOKUSA
| | - Anne McArdle
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseMRC‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA)University of LiverpoolLiverpoolUK
| | - Malcolm J. Jackson
- Department of Musculoskeletal BiologyInstitute of Ageing and Chronic DiseaseMRC‐Arthritis Research UK Centre for Integrated Research into Musculoskeletal Ageing (CIMA)University of LiverpoolLiverpoolUK
| | - Susan V. Brooks
- Department of Molecular and Integrative PhysiologyUniversity of MichiganAnn ArborMIUSA
| | - Holly Van Remmen
- Aging & Metabolism Research ProgramOklahoma Medical Research FoundationOklahoma CityOKUSA
- Oklahoma City VA Medical CenterOklahoma CityOKUSA
| |
Collapse
|
47
|
Giorgetti E, Panesar M, Zhang Y, Joller S, Ronco M, Obrecht M, Lambert C, Accart N, Beckmann N, Doelemeyer A, Perrot L, Fruh I, Mueller M, Pierrel E, Summermatter S, Bidinosti M, Shimshek DR, Brachat S, Nash M. Modulation of Microglia by Voluntary Exercise or CSF1R Inhibition Prevents Age-Related Loss of Functional Motor Units. Cell Rep 2020; 29:1539-1554.e7. [PMID: 31693894 DOI: 10.1016/j.celrep.2019.10.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Revised: 07/27/2019] [Accepted: 10/01/2019] [Indexed: 01/05/2023] Open
Abstract
Age-related loss of skeletal muscle innervation by motor neurons leads to impaired neuromuscular function and is a well-established clinical phenomenon. However, the underlying pathogenesis remains unclear. Studying mice, we find that the number of motor units (MUs) can be maintained by counteracting neurotoxic microglia in the aged spinal cord. We observe that marked innervation changes, detected by motor unit number estimation (MUNE), occur prior to loss of muscle function in aged mice. This coincides with gene expression changes indicative of neuronal remodeling and microglial activation in aged spinal cord. Voluntary exercise prevents loss of MUs and reverses microglia activation. Depleting microglia by CSF1R inhibition also prevents the age-related decline in MUNE and neuromuscular junction disruption, implying a causal link. Our results suggest that age-related changes in spinal cord microglia contribute to neuromuscular decline in aged mice and demonstrate that removal of aged neurotoxic microglia can prevent or reverse MU loss.
Collapse
Affiliation(s)
- Elisa Giorgetti
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland.
| | - Moh Panesar
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Yunyu Zhang
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, Cambridge, MA 02139, USA
| | - Stefanie Joller
- Neuroscience, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Marie Ronco
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Michael Obrecht
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Christian Lambert
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Nathalie Accart
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Nicolau Beckmann
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Arno Doelemeyer
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Ludovic Perrot
- Global Sci Operations, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Isabelle Fruh
- Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Matthias Mueller
- Chemical Biology and Therapeutics, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Eliane Pierrel
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Serge Summermatter
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Michael Bidinosti
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Derya R Shimshek
- Neuroscience, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Sophie Brachat
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland
| | - Mark Nash
- Musculoskeletal Diseases Area, Novartis Institutes for BioMedical Research, 4002 Basel, Switzerland.
| |
Collapse
|
48
|
Properties of Glial Cell at the Neuromuscular Junction Are Incompatible with Synaptic Repair in the SOD1G37R ALS Mouse Model. J Neurosci 2020; 40:7759-7777. [PMID: 32859714 DOI: 10.1523/jneurosci.1748-18.2020] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 08/12/2020] [Accepted: 08/17/2020] [Indexed: 12/17/2022] Open
Abstract
Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease affecting motoneurons (MNs) in a motor-unit (MU)-dependent manner. Glial dysfunction contributes to numerous aspects of the disease. At the neuromuscular junction (NMJ), early alterations in perisynaptic Schwann cell (PSC), glial cells at this synapse, may impact their ability to regulate NMJ stability and repair. Indeed, muscarinic receptors (mAChRs) regulate the repair phenotype of PSCs and are overactivated at disease-resistant NMJs [soleus muscle (SOL)] in SOD1G37R mice. However, it remains unknown whether this is the case at disease-vulnerable NMJs and whether it translates into an impairment of PSC-dependent repair mechanisms. We used SOL and sternomastoid (STM) muscles from SOD1G37R mice and performed Ca2+-imaging to monitor PSC activity and used immunohistochemistry to analyze their repair and phagocytic properties. We show that PSC mAChR-dependent activity was transiently increased at disease-vulnerable NMJs (STM muscle). Furthermore, PSCs from both muscles extended disorganized processes from denervated NMJs and failed to initiate or guide nerve terminal sprouts at disease-vulnerable NMJs, a phenomenon essential for compensatory reinnervation. This was accompanied by a failure of numerous PSCs to upregulate galectin-3 (MAC-2), a marker of glial axonal debris phagocytosis, on NMJ denervation in SOD1 mice. Finally, differences in these PSC-dependent NMJ repair mechanisms were MU type dependent, thus reflecting MU vulnerability in ALS. Together, these results reveal that neuron-glia communication is ubiquitously altered at the NMJ in ALS. This appears to prevent PSCs from adopting a repair phenotype, resulting in a maladapted response to denervation at the NMJ in ALS.SIGNIFICANCE STATEMENT Understanding how the complex interplay between neurons and glial cells ultimately lead to the degeneration of motor neurons and loss of motor function is a fundamental question to comprehend amyotrophic lateral sclerosis (ALS). An early and persistent alteration of glial cell activity takes place at the neuromuscular junction (NMJ), the output of motor neurons, but its impact on NMJ repair remains unknown. Here, we reveal that glial cells at disease-vulnerable NMJs often fail to guide compensatory nerve terminal sprouts and to adopt a phagocytic phenotype on denervated NMJs in SOD1G37R mice. These results show that glial cells at the NMJ elaborate an inappropriate response to NMJ degeneration in a manner that reflects motor-unit (MU) vulnerability and potentially impairs compensatory reinnervation.
Collapse
|
49
|
Bruno C, Sieverding K, Freischmidt A, Satoh T, Walther P, Mayer B, Ludolph AC, Akira S, Yilmazer-Hanke D, Danzer KM, Lobsiger CS, Brenner D, Weishaupt JH. Haploinsufficiency of TANK-binding kinase 1 prepones age-associated neuroinflammatory changes without causing motor neuron degeneration in aged mice. Brain Commun 2020; 2:fcaa133. [PMID: 33005894 PMCID: PMC7519725 DOI: 10.1093/braincomms/fcaa133] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 07/21/2020] [Accepted: 07/27/2020] [Indexed: 12/13/2022] Open
Abstract
Loss-of-function mutations in TANK-binding kinase 1 cause genetic amyotrophic lateral sclerosis and frontotemporal dementia. Consistent with incomplete penetrance in humans, haploinsufficiency of TANK-binding kinase 1 did not cause motor symptoms in mice up to 7 months of age in a previous study. Ageing is the strongest risk factor for neurodegenerative diseases. Hypothesizing that age-dependent processes together with haploinsufficiency of TANK-binding kinase 1 could create a double hit situation that may trigger neurodegeneration, we examined mice with hemizygous deletion of Tbk1 (Tbk1 +/- mice) and wild-type siblings up to 22 months. Compared to 4-month old mice, aged, 22-month old mice showed glial activation, deposition of motoneuronal p62 aggregates, muscular denervation and profound transcriptomic alterations in a set of 800 immune-related genes upon ageing. However, we did not observe differences regarding these measures between aged Tbk1 +/- and wild-type siblings. High age did also not precipitate TAR DNA-binding protein 43 aggregation, neurodegeneration or a neurological phenotype in Tbk1+/ - mice. In young Tbk1+/ - mice, however, we found the CNS immune gene expression pattern shifted towards the age-dependent immune system dysregulation observed in old mice. Conclusively, ageing is not sufficient to precipitate an amyotrophic lateral sclerosis or frontotemporal dementia phenotype or spinal or cortical neurodegeneration in a model of Tbk1 haploinsufficiency. We hypothesize that the consequences of Tbk1 haploinsufficiency may be highly context-dependent and require a specific synergistic stress stimulus to be uncovered.
Collapse
Affiliation(s)
- Clara Bruno
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | | | | | - Takashi Satoh
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Paul Walther
- Central Facility for Electron Microscopy, University of Ulm, 89081 Ulm, Germany
| | - B Mayer
- Institute of Epidemiology and Medical Biometry, Ulm University, Ulm, Germany
| | | | - Shizuo Akira
- Department of Host Defense, Research Institute for Microbial Diseases, Osaka University, Osaka 565-0871, Japan
| | - Deniz Yilmazer-Hanke
- Department of Neurology, Clinical Neuroanatomy, Neurology, University of Ulm, 89081 Ulm, Germany
| | - Karin M Danzer
- Department of Neurology, University of Ulm, 89081 Ulm, Germany
| | - Christian S Lobsiger
- Institut du Cerveau et de la Moelle Épinière, Institut National de la Santé et de la Recherche Médicale, Centre National de la Recherche Scientifique, Sorbonne Université, 75013 Paris, France
| | - David Brenner
- Department of Neurology, University of Ulm, 89081 Ulm, Germany.,Division of Neurodegenerative Disorders, Department of Neurology, Medical Faculty Mannheim, Mannheim Center for Translational Neurosciences, Heidelberg University, 61867 Mannheim, Germany
| | - Jochen H Weishaupt
- Department of Neurology, University of Ulm, 89081 Ulm, Germany.,Division of Neurodegenerative Disorders, Department of Neurology, Medical Faculty Mannheim, Mannheim Center for Translational Neurosciences, Heidelberg University, 61867 Mannheim, Germany
| |
Collapse
|
50
|
DOK7 Gene Therapy Enhances Neuromuscular Junction Innervation and Motor Function in Aged Mice. iScience 2020; 23:101385. [PMID: 32758427 PMCID: PMC7452162 DOI: 10.1016/j.isci.2020.101385] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 06/21/2020] [Accepted: 07/16/2020] [Indexed: 12/14/2022] Open
Abstract
Muscle denervation at the neuromuscular junction (NMJ), the essential synapse between motor neuron and skeletal muscle, is associated with age-related motor impairment. Therefore, improving muscle innervation at aged NMJs may be an effective therapeutic strategy for treating the impairment. We previously demonstrated that the muscle protein Dok-7 plays an essential role in NMJ formation, and, indeed, its forced expression in muscle enlarges NMJs. Moreover, therapeutic administration of an adeno-associated virus vector encoding human Dok-7 (DOK7 gene therapy) suppressed muscle denervation and enhanced motor activity in a mouse model of amyotrophic lateral sclerosis (ALS). Here, we show that DOK7 gene therapy significantly enhances motor function and muscle strength together with NMJ innervation in aged mice. Furthermore, the treated mice showed greatly increased compound muscle action potential (CMAP) amplitudes compared with the controls, suggesting enhanced neuromuscular transmission. Thus, therapies aimed at enhancing NMJ innervation have potential for treating age-related motor impairment. DOK7 gene therapy enhances motor function and muscle strength in aged (≥2 years) mice DOK7 gene therapy enhances neuromuscular junction (NMJ) innervation in aged mice DOK7 gene therapy increases compound muscle action potential amplitudes in aged mice Enhancing NMJ innervation in the elderly may strengthen muscles and motor activities
Collapse
|