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Karliner J, Liu Y, Merry DE. Mutant androgen receptor induces neurite loss and senescence independently of ARE binding in a neuronal model of SBMA. Proc Natl Acad Sci U S A 2024; 121:e2321408121. [PMID: 38976730 PMCID: PMC11260106 DOI: 10.1073/pnas.2321408121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 06/11/2024] [Indexed: 07/10/2024] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a slowly progressing neuromuscular disease caused by a polyglutamine (polyQ)-encoding CAG trinucleotide repeat expansion in the androgen receptor (AR) gene, leading to AR aggregation, lower motor neuron death, and muscle atrophy. AR is a ligand-activated transcription factor that regulates neuronal architecture and promotes axon regeneration; however, whether AR transcriptional functions contribute to disease pathogenesis is not fully understood. Using a differentiated PC12 cell model of SBMA, we identified dysfunction of polyQ-expanded AR in its regulation of neurite growth and maintenance. Specifically, we found that in the presence of androgens, polyQ-expanded AR inhibited neurite outgrowth, induced neurite retraction, and inhibited neurite regrowth. This dysfunction was independent of polyQ-expanded AR transcriptional activity at androgen response elements (ARE). We further showed that the formation of polyQ-expanded AR intranuclear inclusions promoted neurite retraction, which coincided with reduced expression of the neuronal differentiation marker β-III-Tubulin. Finally, we revealed that cell death is not the primary outcome for cells undergoing neurite retraction; rather, these cells become senescent. Our findings reveal that mechanisms independent of AR canonical transcriptional activity underly neurite defects in a cell model of SBMA and identify senescence as a pathway implicated in this pathology. These findings suggest that in the absence of a role for AR canonical transcriptional activity in the SBMA pathologies described here, the development of SBMA therapeutics that preserve this activity may be desirable. This approach may be broadly applicable to other polyglutamine diseases such as Huntington's disease and spinocerebellar ataxias.
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Affiliation(s)
- Jordyn Karliner
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
| | - Yuhong Liu
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
| | - Diane E. Merry
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA19107
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2
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Lisberg A, Liu Y, Merry DE. Blocking the dimerization of polyglutamine-expanded androgen receptor protects cells from DHT-induced toxicity by increasing AR turnover. J Biol Chem 2024; 300:107246. [PMID: 38556081 PMCID: PMC11067348 DOI: 10.1016/j.jbc.2024.107246] [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: 02/06/2024] [Revised: 03/06/2024] [Accepted: 03/15/2024] [Indexed: 04/02/2024] Open
Abstract
Spinal and bulbar muscular atrophy (SBMA) is a neuromuscular degenerative disease caused by a polyglutamine expansion in the androgen receptor (AR). This mutation causes AR to misfold and aggregate, contributing to toxicity in and degeneration of motor neurons and skeletal muscle. There is currently no effective treatment or cure for this disease. The role of an interdomain interaction between the amino- and carboxyl-termini of AR, termed the N/C interaction, has been previously identified as a component of androgen receptor-induced toxicity in cell and mouse models of SBMA. However, the mechanism by which this interaction contributes to disease pathology is unclear. This work seeks to investigate this mechanism by interrogating the role of AR homodimerization- a unique form of the N/C-interaction- in SBMA. We show that, although the AR N/C-interaction is reduced by polyglutamine-expansion, homodimers of 5α-dihydrotestosterone (DHT)-bound AR are increased. Additionally, blocking homodimerization results in decreased AR aggregation and toxicity in cell models. Blocking homodimerization results in the increased degradation of AR, which likely plays a role in the protective effects of this mutation. Overall, this work identifies a novel mechanism in SBMA pathology that may represent a novel target for the development of therapeutics for this disease.
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Affiliation(s)
- Allison Lisberg
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Yuhong Liu
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Diane E Merry
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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3
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DeBartolo D, Arnold FJ, Liu Y, Molotsky E, Tang HY, Merry DE. Differentially disrupted spinal cord and muscle energy metabolism in spinal and bulbar muscular atrophy. JCI Insight 2024; 9:e178048. [PMID: 38452174 PMCID: PMC11128210 DOI: 10.1172/jci.insight.178048] [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: 11/28/2023] [Accepted: 02/27/2024] [Indexed: 03/09/2024] Open
Abstract
Prior studies showed that polyglutamine-expanded androgen receptor (AR) is aberrantly acetylated and that deacetylation of the mutant AR by overexpression of nicotinamide adenine dinucleotide-dependent (NAD+-dependent) sirtuin 1 is protective in cell models of spinal and bulbar muscular atrophy (SBMA). Based on these observations and reduced NAD+ in muscles of SBMA mouse models, we tested the therapeutic potential of NAD+ restoration in vivo by treating postsymptomatic transgenic SBMA mice with the NAD+ precursor nicotinamide riboside (NR). NR supplementation failed to alter disease progression and had no effect on increasing NAD+ or ATP content in muscle, despite producing a modest increase of NAD+ in the spinal cords of SBMA mice. Metabolomic and proteomic profiles of SBMA quadriceps muscles indicated alterations in several important energy-related pathways that use NAD+, in addition to the NAD+ salvage pathway, which is critical for NAD+ regeneration for use in cellular energy production. We also observed decreased mRNA levels of nicotinamide riboside kinase 2 (Nmrk2), which encodes a key kinase responsible for NR phosphorylation, allowing its use by the NAD+ salvage pathway. Together, these data suggest a model in which NAD+ levels are significantly decreased in muscles of an SBMA mouse model and intransigent to NR supplementation because of decreased levels of Nmrk2.
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Affiliation(s)
- Danielle DeBartolo
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Frederick J. Arnold
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Yuhong Liu
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Elana Molotsky
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Hsin-Yao Tang
- Proteomics and Metabolomics Shared Resource, Molecular and Cellular Oncogenesis Program, The Wistar Institute, Philadelphia, Pennsylvania, USA
| | - Diane E. Merry
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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4
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Dennhag N, Kahsay A, Nissen I, Nord H, Chermenina M, Liu J, Arner A, Liu JX, Backman LJ, Remeseiro S, von Hofsten J, Pedrosa Domellöf F. fhl2b mediates extraocular muscle protection in zebrafish models of muscular dystrophies and its ectopic expression ameliorates affected body muscles. Nat Commun 2024; 15:1950. [PMID: 38431640 PMCID: PMC10908798 DOI: 10.1038/s41467-024-46187-x] [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: 09/12/2023] [Accepted: 02/16/2024] [Indexed: 03/05/2024] Open
Abstract
In muscular dystrophies, muscle fibers loose integrity and die, causing significant suffering and premature death. Strikingly, the extraocular muscles (EOMs) are spared, functioning well despite the disease progression. Although EOMs have been shown to differ from body musculature, the mechanisms underlying this inherent resistance to muscle dystrophies remain unknown. Here, we demonstrate important differences in gene expression as a response to muscle dystrophies between the EOMs and trunk muscles in zebrafish via transcriptomic profiling. We show that the LIM-protein Fhl2 is increased in response to the knockout of desmin, plectin and obscurin, cytoskeletal proteins whose knockout causes different muscle dystrophies, and contributes to disease protection of the EOMs. Moreover, we show that ectopic expression of fhl2b can partially rescue the muscle phenotype in the zebrafish Duchenne muscular dystrophy model sapje, significantly improving their survival. Therefore, Fhl2 is a protective agent and a candidate target gene for therapy of muscular dystrophies.
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Affiliation(s)
- Nils Dennhag
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Abraha Kahsay
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Itzel Nissen
- Department of Medical and Translational Biology; Section of Molecular Medicine, Umeå University, Umeå, Sweden
- Wallenberg Center for Molecular Medicine (WCMM), Umeå University, Umeå, Sweden
| | - Hanna Nord
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
| | - Maria Chermenina
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden
| | - Jiao Liu
- Div. Thoracic Surgery, Dept. Clinical Sciences, Lund University, Lund, Sweden
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Anders Arner
- Div. Thoracic Surgery, Dept. Clinical Sciences, Lund University, Lund, Sweden
| | - Jing-Xia Liu
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
| | - Ludvig J Backman
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden
| | - Silvia Remeseiro
- Department of Medical and Translational Biology; Section of Molecular Medicine, Umeå University, Umeå, Sweden
- Wallenberg Center for Molecular Medicine (WCMM), Umeå University, Umeå, Sweden
| | - Jonas von Hofsten
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden.
| | - Fatima Pedrosa Domellöf
- Department of Medical and Translational Biology, Umeå University, Umeå, Sweden.
- Department of Clinical Sciences, Ophthalmology, Umeå University, Umeå, Sweden.
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5
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Richardson K, Sengupta M, Sujkowski A, Libohova K, Harris AC, Wessells R, Merry DE, Todi SV. A phenotypically robust model of spinal and bulbar muscular atrophy in Drosophila. J Neurosci Res 2024; 102:e25278. [PMID: 38284836 PMCID: PMC11237963 DOI: 10.1002/jnr.25278] [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: 07/19/2023] [Revised: 10/14/2023] [Accepted: 11/05/2023] [Indexed: 01/30/2024]
Abstract
Spinal and bulbar muscular atrophy (SBMA) is an X-linked disorder that affects males who inherit the androgen receptor (AR) gene with an abnormal CAG triplet repeat expansion. The resulting protein contains an elongated polyglutamine (polyQ) tract and causes motor neuron degeneration in an androgen-dependent manner. The precise molecular sequelae of SBMA are unclear. To assist with its investigation and the identification of therapeutic options, we report here a new model of SBMA in Drosophila melanogaster. We generated transgenic flies that express the full-length, human AR with a wild-type or pathogenic polyQ repeat. Each transgene is inserted into the same safe harbor site on the third chromosome of the fly as a single copy and in the same orientation. Expression of pathogenic AR, but not of its wild-type variant, in neurons or muscles leads to consistent, progressive defects in longevity and motility that are concomitant with polyQ-expanded AR protein aggregation and reduced complexity in neuromuscular junctions. Additional assays show adult fly eye abnormalities associated with the pathogenic AR species. The detrimental effects of pathogenic AR are accentuated by feeding flies the androgen, dihydrotestosterone. This new, robust SBMA model can be a valuable tool toward future investigations of this incurable disease.
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Affiliation(s)
- Kristin Richardson
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Medha Sengupta
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Alyson Sujkowski
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Kozeta Libohova
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Autumn C Harris
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Maximizing Access to Science Careers Program, Wayne State University, Detroit, Michigan, USA
| | - Robert Wessells
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan, USA
| | - Diane E Merry
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Sokol V Todi
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, Michigan, USA
- Maximizing Access to Science Careers Program, Wayne State University, Detroit, Michigan, USA
- Department of Neurology, Wayne State University School of Medicine, Detroit, Michigan, USA
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6
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Chen J, Xu Q, Wang X, Xu Z, Chen X. Cullin-3 intervenes in muscle atrophy in the elderly by mediating the degradation of nAchRs ubiquitination. Exp Gerontol 2023; 183:112318. [PMID: 37913946 DOI: 10.1016/j.exger.2023.112318] [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: 09/07/2023] [Revised: 10/20/2023] [Accepted: 10/22/2023] [Indexed: 11/03/2023]
Abstract
Sarcopenia involves in the loss of muscle mass associated with aging, which is the major cause of progressive muscle weakness and deterioration in older adults. Muscle atrophy is a direct presentation of sarcopenia, and it greatly contributes to the decline in quality of life among older adults. Neuromuscular junction (NMJ) stability is the key link to maintain muscle function. Besides, the degenerative change of NMJ promotes the process of muscle atrophy in the elderly. Based on previous transcriptome sequencing and bioinformatics analyses of aged muscle, this study used the 18-month-old aged mouse model and the 6-month-old young mouse model to deliberate the role and underlying mechanisms of Cullin-3 (Cul3) in age-related muscle atrophy. The results of reverse transcriptase polymerase chain reaction (RT-PCR) and immunoblotting analysis showed that the expression of CUL3 increased in aged muscle tissue, while the expression level of postsynaptic membrane nicotinic acetylcholine receptors (nAChRs) decreased significantly, which manfested a negative correlation. Meanwhile, immunofluorescence demonstrated that Cul3 was highly expressed in senile muscle NMJ. The results of ubiquitin indicated that the ubiquitin level of aged muscle nAChRs was evidently increased. Co-immunoprecipitation furtherly verified the correlation between Cul3 and nAChRs. Taken together, Cul3 may mediate the ubiquitination degradation of nAChRs protein at the NMJ site in aged mice, leading to NMJ degeneration and accelerated atrophy of fast-twitch muscle fibers in aged muscle. As a prominent element to maintain the stability of NMJ, Cul3 is supposed to be one of candidate intervention targets in sarcopenia.
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Affiliation(s)
- Jintao Chen
- The First Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China.
| | - Qun Xu
- Zhejiang University, School of Medicine, Hangzhou, China
| | - Xinyi Wang
- The First Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China
| | - Zherong Xu
- Department of Geriatrics, The First Affiliated Hospital, Zhejiang University, School of Medicine, Hangzhou, China.
| | - Xujiao Chen
- Department of Geriatrics, Zhejiang Provincial Hospital of Chinese Medicine, Hangzhou, China; Zhejiang Hospital, Hangzhou, China.
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7
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Rossi L, Santos KBS, Mota BIS, Pimenta J, Oliveira B, Machado CA, Fernandes HB, Barbosa LA, Rodrigues HA, Teixeira GHM, Gomes-Martins GA, Chaimowicz GF, Queiroz-Junior CM, Chaves I, Tapia JC, Teixeira MM, Costa VV, Miranda AS, Guatimosim C. Neuromuscular defects after infection with a beta coronavirus in mice. Neurochem Int 2023; 169:105567. [PMID: 37348761 PMCID: PMC10281698 DOI: 10.1016/j.neuint.2023.105567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/14/2023] [Accepted: 06/19/2023] [Indexed: 06/24/2023]
Abstract
COVID-19 affects primarily the lung. However, several other systemic alterations, including muscle weakness, fatigue and myalgia have been reported and may contribute to the disease outcome. We hypothesize that changes in the neuromuscular system may contribute to the latter symptoms observed in COVID-19 patients. Here, we showed that C57BL/6J mice inoculated intranasally with the murine betacoronavirus hepatitis coronavirus 3 (MHV-3), a model for studying COVID-19 in BSL-2 conditions that emulates severe COVID-19, developed robust motor alterations in muscle strength and locomotor activity. The latter changes were accompanied by degeneration and loss of motoneurons that were associated with the presence of virus-like particles inside the motoneuron. At the neuromuscular junction level, there were signs of atrophy and fragmentation in synaptic elements of MHV-3-infected mice. Furthermore, there was muscle atrophy and fiber type switch with alteration in myokines levels in muscles of MHV-3-infected mice. Collectively, our results show that acute infection with a betacoronavirus leads to robust motor impairment accompanied by neuromuscular system alteration.
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Affiliation(s)
- Leonardo Rossi
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Kivia B S Santos
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Barbara I S Mota
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Jordane Pimenta
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Bruna Oliveira
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Caroline A Machado
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Heliana B Fernandes
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Leticia A Barbosa
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Hermann A Rodrigues
- Departamento de Ciências Básicas da Vida, Universidade Federal de Juiz de Fora, Campus Governador Valadares, MG, Brazil
| | - Gabriel H M Teixeira
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gabriel A Gomes-Martins
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Gabriel F Chaimowicz
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Celso Martins Queiroz-Junior
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ian Chaves
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Juan C Tapia
- School of Medicine, University of Talca, Talca, Chile
| | - Mauro M Teixeira
- Department of Biochemistry, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Vivian V Costa
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Aline S Miranda
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Cristina Guatimosim
- Department of Morphology, Institute of Biological Sciences, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
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8
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Barone C, Qi X. Altered Metabolism in Motor Neuron Diseases: Mechanism and Potential Therapeutic Target. Cells 2023; 12:1536. [PMID: 37296656 PMCID: PMC10252517 DOI: 10.3390/cells12111536] [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: 04/08/2023] [Revised: 05/21/2023] [Accepted: 05/31/2023] [Indexed: 06/12/2023] Open
Abstract
Motor Neuron Diseases (MND) are neurological disorders characterized by a loss of varying motor neurons resulting in decreased physical capabilities. Current research is focused on hindering disease progression by determining causes of motor neuron death. Metabolic malfunction has been proposed as a promising topic when targeting motor neuron loss. Alterations in metabolism have also been noted at the neuromuscular junction (NMJ) and skeletal muscle tissue, emphasizing the importance of a cohesive system. Finding metabolism changes consistent throughout both neurons and skeletal muscle tissue could pose as a target for therapeutic intervention. This review will focus on metabolic deficits reported in MNDs and propose potential therapeutic targets for future intervention.
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Affiliation(s)
| | - Xin Qi
- Department of Physiology and Biophysics, School of Medicine Case Western Reserve University, Cleveland, OH 44106-4970, USA;
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Yang Q, Wang Y, Zhao C, Pang S, Lu J, Chan P. α-Synuclein aggregation causes muscle atrophy through neuromuscular junction degeneration. J Cachexia Sarcopenia Muscle 2023; 14:226-242. [PMID: 36416282 PMCID: PMC9891985 DOI: 10.1002/jcsm.13123] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/20/2022] [Revised: 09/15/2022] [Accepted: 10/12/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Sarcopenia is common in patients with Parkinson's disease (PD), showing mitochondrial oxidative stress in skeletal muscle. The aggregation of α-synuclein (α-Syn) to induce oxidative stress is a key pathogenic process of PD; nevertheless, we know little about its potential role in regulating peripheral nerves and the function of the muscles they innervate. METHODS To investigate the role of α-Syn aggregation on neuromuscular system, we used the Thy1 promoter to overexpress human α-Syn transgenic mice (mThy1-hSNCA). hα-Syn expression was evaluated by western blot, and its localization was determined by confocal microscopy. The impact of α-Syn aggregation on the structure and function of skeletal muscle mitochondria and neuromuscular junctions (NMJs), as well as muscle mass and function were characterized by flow cytometry, transmission electron microscopy, Seahorse XF24 metabolic assay, and AAV9 in vivo injection. We assessed the regenerative effect of mitochondrial-targeted superoxide dismutase (Mito-TEMPO) after skeletal muscle injury in mThy1-hSNCA mice. RESULTS Overexpressed hα-Syn protein localized in motor neuron axons and NMJs in muscle and formed aggregates. α-Syn aggregation increased the number of abnormal mitochondrial in the intramuscular axons and NMJs by over 60% (P < 0.01), which inhibited the release of acetylcholine (ACh) from presynaptic vesicles in NMJs (P < 0.05). The expression of genes associated with NMJ activity, neurotransmission and regulation of reactive oxygen species (ROS) metabolic process were significantly decreased in mThy1-hSNCA mice, resulting in ROS production elevated by ~220% (P < 0.05), thereby exacerbating oxidative stress. Such process altered mitochondrial spatial relationships to sarcomeric structures, decreased Z-line spacing by 36% (P < 0.05) and increased myofibre apoptosis by ~10% (P < 0.05). Overexpression of α-Syn altered the metabolic profile of muscle satellite cells (MuSCs), including basal respiratory capacity (~170% reduction) and glycolytic capacity (~150% reduction) (P < 0.05) and decreased cell migration and fusion during muscle regeneration (~60% and ~40%, respectively) (P < 0.05). We demonstrated that Mito-TEMPO treatment could restore the oxidative stress status (the complex I/V protein and enzyme activities increased ~200% and ~150%, respectively), which caused by α-Syn aggregation, and improve the ability of muscle regeneration after injury. In addition, the NMJ receptor fragmentation and ACh secretion were also improved. CONCLUSIONS These results reveal that the α-synuclein aggregation plays an important role in regulating acetylcholine release from neuromuscular junctions and induces intramuscular mitochondrial oxidative stress, which can provide new insights into the aetiology of muscle atrophy in patients with Parkinson's disease.
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Affiliation(s)
- Qiumei Yang
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Yanyan Wang
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Chunsong Zhao
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Shimin Pang
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China
| | - Jing Lu
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China
| | - Piu Chan
- Department of Neurology, Geriatrics and Neurobiology, National Clinical Research Center of Geriatric Disorders, Xuanwu Hospital, Capital Medical University, Beijing, China.,Advanced Innovation Center for Human Brain Protection, Capital Medical University, Beijing, China.,Clinical Center for Parkinson's Disease, Capital Medical University, Beijing Institute of Geriatrics, Beijing, China.,Key Laboratory for Neurodegenerative Disease of the Ministry of Education, Beijing Key Laboratory for Parkinson's Disease, Beijing Institute of Brain Disorders, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China
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10
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In vivo imaging of axonal transport in peripheral nerves of rodent forelimbs. Neuronal Signal 2023; 7:NS20220098. [PMID: 36743438 PMCID: PMC9867938 DOI: 10.1042/ns20220098] [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: 12/01/2022] [Revised: 12/23/2022] [Accepted: 01/05/2023] [Indexed: 01/07/2023] Open
Abstract
Axonal transport is the essential process by which neurons actively traffic a variety of cargoes between the cell soma and axon terminals. Accordingly, dysfunctional axonal transport is linked to many nervous system conditions. Therefore, being able to image and quantify this dynamic process in live neurons of animal disease models is beneficial for understanding neuropathology and testing new therapies at the preclinical level. As such, intravital approaches have been developed to assess cargo movement in the hindlimb sciatic nerves of live, anaesthetised mice. Here, we describe an adapted method for in vivo imaging of axonal transport in intact median and ulnar nerves of the rodent forelimb. Injection of a fluorescently labelled and non-toxic fragment of tetanus neurotoxin (HCT) into the mouse forepaw permits the identification of signalling endosomes in intact axons of median and ulnar nerves. Through immunofluorescent analysis of forelimb lumbrical muscles and median/ulnar nerves, we confirmed that HCT is taken up at motor nerve terminals and predominantly locates to motor axons. We then showed that the baseline trafficking of signalling endosomes is similar between the median/ulnar nerves and the sciatic nerve in adult wild-type mice. Importantly, this adapted method can be readily tailored for assessment of additional cargoes, such as mitochondria. By measuring transport in forelimb and hindlimb nerves, comparative anatomical and functional analyses can be performed in rodent disease models to aid our understanding of peripheral nerve disease pathogenesis and response to injury.
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