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Zhang X, Avellaneda J, Spletter ML, Lemke SB, Mangeol P, Habermann BH, Schnorrer F. Mechanoresponsive regulation of myogenesis by the force-sensing transcriptional regulator Tono. Curr Biol 2024; 34:4143-4159.e6. [PMID: 39163855 DOI: 10.1016/j.cub.2024.07.079] [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: 08/17/2023] [Revised: 05/26/2024] [Accepted: 07/22/2024] [Indexed: 08/22/2024]
Abstract
Muscle morphogenesis is a multi-step program, starting with myoblast fusion, followed by myotube-tendon attachment and sarcomere assembly, with subsequent sarcomere maturation, mitochondrial amplification, and specialization. The correct chronological order of these steps requires precise control of the transcriptional regulators and their effectors. How this regulation is achieved during muscle development is not well understood. In a genome-wide RNAi screen in Drosophila, we identified the BTB-zinc-finger protein Tono (CG32121) as a muscle-specific transcriptional regulator. tono mutant flight muscles display severe deficits in mitochondria and sarcomere maturation, resulting in uncontrolled contractile forces causing muscle rupture and degeneration during development. Tono protein is expressed during sarcomere maturation and localizes in distinct condensates in flight muscle nuclei. Interestingly, internal pressure exerted by the maturing sarcomeres deforms the muscle nuclei into elongated shapes and changes the Tono condensates, suggesting that Tono senses the mechanical status of the muscle cells. Indeed, external mechanical pressure on the muscles triggers rapid liquid-liquid phase separation of Tono utilizing its BTB domain. Thus, we propose that Tono senses high mechanical pressure to adapt muscle transcription, specifically at the sarcomere maturation stages. Consistently, tono mutant muscles display specific defects in a transcriptional switch that represses early muscle differentiation genes and boosts late ones. We hypothesize that a similar mechano-responsive regulation mechanism may control the activity of related BTB-zinc-finger proteins that, if mutated, can result in uncontrolled force production in human muscle.
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Affiliation(s)
- Xu Zhang
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Parc Scientifique de Luminy, 13288 Marseille, France; Max Planck Institute of Biochemistry, Am Klopferspitz, Martinsried, 82152 Munich, Germany; School of Life Science and Engineering, Foshan University, Foshan 52800, Guangdong, China
| | - Jerome Avellaneda
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Parc Scientifique de Luminy, 13288 Marseille, France
| | - Maria L Spletter
- Max Planck Institute of Biochemistry, Am Klopferspitz, Martinsried, 82152 Munich, Germany; Department of Physiological Chemistry, Biomedical Center, Ludwig Maximilians University of Munich, Großhaderner Strasse, Martinsried, 82152 Munich, Germany; Division of Biological and Biomedical Systems, School of Science and Engineering, University of Missouri-Kansas City, Rockhill Road, Kansas City, MO 64110, USA
| | - Sandra B Lemke
- Max Planck Institute of Biochemistry, Am Klopferspitz, Martinsried, 82152 Munich, Germany
| | - Pierre Mangeol
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Parc Scientifique de Luminy, 13288 Marseille, France
| | - Bianca H Habermann
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Parc Scientifique de Luminy, 13288 Marseille, France; Max Planck Institute of Biochemistry, Am Klopferspitz, Martinsried, 82152 Munich, Germany
| | - Frank Schnorrer
- Aix Marseille University, CNRS, IBDM, Turing Centre for Living Systems, Parc Scientifique de Luminy, 13288 Marseille, France; Max Planck Institute of Biochemistry, Am Klopferspitz, Martinsried, 82152 Munich, Germany.
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Vanhauwaert R, Oury J, Vankerckhoven B, Steyaert C, Jensen SM, Vergoossen DLE, Kneip C, Santana L, Lim JL, Plomp JJ, Augustinus R, Koide S, Blanchetot C, Ulrichts P, Huijbers MG, Silence K, Burden SJ. ARGX-119 is an agonist antibody for human MuSK that reverses disease relapse in a mouse model of congenital myasthenic syndrome. Sci Transl Med 2024; 16:eado7189. [PMID: 39292800 DOI: 10.1126/scitranslmed.ado7189] [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: 02/17/2024] [Revised: 04/29/2024] [Accepted: 08/26/2024] [Indexed: 09/20/2024]
Abstract
Muscle-specific kinase (MuSK) is essential for the formation, function, and preservation of neuromuscular synapses. Activation of MuSK by a MuSK agonist antibody may stabilize or improve the function of the neuromuscular junction (NMJ) in patients with disorders of the NMJ, such as congenital myasthenia (CM). Here, we generated and characterized ARGX-119, a first-in-class humanized agonist monoclonal antibody specific for MuSK, that is being developed for treatment of patients with neuromuscular diseases. We performed in vitro ligand-binding assays to show that ARGX-119 binds with high affinity to the Frizzled-like domain of human, nonhuman primate, rat, and mouse MuSK, without off-target binding, making it suitable for clinical development. Within the Fc region, ARGX-119 harbors L234A and L235A mutations to diminish potential immune-activating effector functions. Its mode of action is to activate MuSK, without interfering with its natural ligand neural Agrin, and cluster acetylcholine receptors in a dose-dependent manner, thereby stabilizing neuromuscular function. In a mouse model of DOK7 CM, ARGX-119 prevented early postnatal lethality and reversed disease relapse in adult Dok7 CM mice by restoring neuromuscular function and reducing muscle weakness and fatigability in a dose-dependent manner. Pharmacokinetic studies in nonhuman primates, rats, and mice revealed a nonlinear PK behavior of ARGX-119, indicative of target-mediated drug disposition and in vivo target engagement. On the basis of this proof-of-concept study, ARGX-119 has the potential to alleviate neuromuscular diseases hallmarked by impaired neuromuscular synaptic function, warranting further clinical development.
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Affiliation(s)
| | - Julien Oury
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
| | | | | | - Stine Marie Jensen
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Dana L E Vergoossen
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | | | - Leah Santana
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
| | - Jamie L Lim
- argenx, 9052 Zwijnaarde, Belgium
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Jaap J Plomp
- Department of Neurology, Leiden University Medical Center, 2333 ZA Leiden, Netherlands
| | - Roy Augustinus
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
| | - Shohei Koide
- Department of Biochemistry and Molecular Pharmacology, NYU School of Medicine, New York, NY 10016, USA
- Perlmutter Cancer Center, NYU Langone Health, New York, NY 10016, USA
| | | | | | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, 2300 RC Leiden, Netherlands
- Department of Neurology, Leiden University Medical Center, 2333 ZA Leiden, Netherlands
| | | | - Steven J Burden
- Helen L. and Martin S. Kimmel Center for Biology and Medicine at Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY 10016, USA
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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Bao Z, Cui C, Liu C, Long Y, Wong RMY, Chai S, Qin L, Rubin C, Yip BHK, Xu Z, Jiang Q, Chow SK, Cheung W. Prevention of age-related neuromuscular junction degeneration in sarcopenia by low-magnitude high-frequency vibration. Aging Cell 2024; 23:e14156. [PMID: 38532712 PMCID: PMC11258441 DOI: 10.1111/acel.14156] [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: 09/17/2023] [Revised: 03/11/2024] [Accepted: 03/12/2024] [Indexed: 03/28/2024] Open
Abstract
Neuromuscular junction (NMJ) degeneration is one of pathological factors of sarcopenia. Low-magnitude high-frequency vibration (LMHFV) was reported effective in alleviating the sarcopenia progress. However, no previous study has investigated treatment effects of LMHFV targeting NMJ degeneration in sarcopenia. We first compared morphological differences of NMJ between sarcopenic and non-sarcopenic subjects, as well as young and old C57BL/6 mice. We then systematically characterized the age-related degeneration of NMJ in SAMP8 against its control strain, SAMR1 mice, from 3 to 12 months old. We also investigated effects of LMHFV in SAMP8 on the maintenance of NMJ during the onset of sarcopenia with respect to the Agrin-LRP4-MuSK-Dok7 pathway and investigated the mechanism related to ERK1/2 signaling. We observed sarcopenic/old NMJ presented increased acetylcholine receptors (AChRs) cluster fragmentation and discontinuity than non-sarcopenic/young NMJ. In SAMP8, NMJ degeneration (morphologically at 6 months and functionally at 8 months) was observed associated with the sarcopenia onset (10 months). SAMR1 showed improved NMJ morphology and function compared with SAMP8 at 10 months. Skeletal muscle performance was improved at Month 4 post-LMHFV treatment. Vibration group presented improved NMJ function at Months 2 and 6 posttreatment, accompanied with alleviated morphological degeneration at Month 4 posttreatment. LMHFV increased Dok7 expression at Month 4 posttreatment. In vitro, LMHFV could promote AChRs clustering in myotubes by increasing Dok7 expression through suppressing ERK1/2 phosphorylation. In conclusion, NMJ degeneration was observed associated with the sarcopenia onset in SAMP8. LMHFV may attenuate NMJ degeneration and sarcopenia progression by increasing Dok7 expression through suppressing ERK1/2 phosphorylation.
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Affiliation(s)
- Zhengyuan Bao
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingJiangsuChina
| | - Can Cui
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - Chaoran Liu
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - Yufeng Long
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - Ronald Man Yeung Wong
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - Senlin Chai
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingJiangsuChina
| | - Ling Qin
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
| | - Clinton Rubin
- Department of Biomedical EngineeringStony Brook UniversityStony BrookNew YorkUSA
| | - Benjamin Hon Kei Yip
- School of Public Health and Primary Care, Faculty of MedicineThe Chinese University of Hong KongHong Kong SARChina
| | - Zhihong Xu
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingJiangsuChina
| | - Qing Jiang
- Division of Sports Medicine and Adult Reconstructive Surgery, Department of Orthopedic Surgery, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical SchoolNanjing UniversityNanjingJiangsuChina
| | - Simon Kwoon‐Ho Chow
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
- Department of Orthopaedic SurgeryStanford UniversityStanfordCaliforniaUSA
| | - Wing‐Hoi Cheung
- Musculoskleletal Research Laboratory, Department of Orthopaedics and Traumatology, Prince of Wales HospitalThe Chinese University of Hong KongHong Kong SARChina
- Li Ka Shing Institute of Health SciencesThe Chinese University of Hong KongHong Kong SARChina
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4
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Kaplan MM, Zeidler M, Knapp A, Hölzl M, Kress M, Fritsch H, Krogsdam A, Flucher BE. Spatial transcriptomics in embryonic mouse diaphragm muscle reveals regional gradients and subdomains of developmental gene expression. iScience 2024; 27:110018. [PMID: 38883818 PMCID: PMC11177202 DOI: 10.1016/j.isci.2024.110018] [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: 12/20/2023] [Revised: 03/22/2024] [Accepted: 05/14/2024] [Indexed: 06/18/2024] Open
Abstract
The murine embryonic diaphragm is a primary model for studying myogenesis and neuro-muscular synaptogenesis, both representing processes regulated by spatially organized genetic programs of myonuclei located in distinct myodomains. However, a spatial gene expression pattern of embryonic mouse diaphragm has not been reported. Here, we provide spatially resolved gene expression data for horizontally sectioned embryonic mouse diaphragms at embryonic days E14.5 and E18.5. These data reveal gene signatures for specific muscle regions with distinct maturity and fiber type composition, as well as for a central neuromuscular junction (NMJ) and a peripheral myotendinous junction (MTJ) compartment. Comparing spatial expression patterns of wild-type mice with those of transgenic mice lacking either the skeletal muscle calcium channel CaV1.1 or β-catenin, reveals curtailed muscle development and dysregulated expression of genes potentially involved in NMJ formation. Altogether, these datasets provide a powerful resource for further studies of muscle development and NMJ formation in the mouse.
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Affiliation(s)
| | - Maximilian Zeidler
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Annabella Knapp
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Martina Hölzl
- Deep Sequencing Core and Institute for Bioinformatics Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Michaela Kress
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Helga Fritsch
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Anne Krogsdam
- Deep Sequencing Core and Institute for Bioinformatics Medical University Innsbruck, 6020 Innsbruck, Austria
| | - Bernhard E Flucher
- Institute of Physiology, Medical University Innsbruck, 6020 Innsbruck, Austria
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Tam LM, Rand MD. Review: myogenic and muscle toxicity targets of environmental methylmercury exposure. Arch Toxicol 2024; 98:1645-1658. [PMID: 38546836 PMCID: PMC11105986 DOI: 10.1007/s00204-024-03724-3] [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: 12/12/2023] [Accepted: 02/29/2024] [Indexed: 05/01/2024]
Abstract
A number of environmental toxicants are noted for their activity that leads to declined motor function. However, the role of muscle as a proximal toxicity target organ for environmental agents has received considerably less attention than the toxicity targets in the nervous system. Nonetheless, the effects of conventional neurotoxicants on processes of myogenesis and muscle maintenance are beginning to resolve a concerted role of muscle as a susceptible toxicity target. A large body of evidence from epidemiological, animal, and in vitro studies has established that methylmercury (MeHg) is a potent developmental toxicant, with the nervous system being a preferred target. Despite its well-recognized status as a neurotoxicant, there is accumulating evidence that MeHg also targets muscle and neuromuscular development as well as contributes to the etiology of motor defects with prenatal MeHg exposure. Here, we summarize evidence for targets of MeHg in the morphogenesis and maintenance of skeletal muscle that reveal effects on MeHg distribution, myogenesis, myotube formation, myotendinous junction formation, neuromuscular junction formation, and satellite cell-mediated muscle repair. We briefly recapitulate the molecular and cellular mechanisms of skeletal muscle development and highlight the pragmatic role of alternative model organisms, Drosophila and zebrafish, in delineating the molecular underpinnings of muscle development and MeHg-mediated myotoxicity. Finally, we discuss how toxicity targets in muscle development may inform the developmental origins of health and disease theory to explain the etiology of environmentally induced adult motor deficits and accelerated decline in muscle fitness with aging.
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Affiliation(s)
- Lok Ming Tam
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY, 14642, USA.
- Clinical and Translational Science Institute, University of Rochester Medical Center, 601 Elmwood Ave, Rochester, NY, 14642, USA.
| | - Matthew D Rand
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Rochester, NY, 14642, USA
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Schellino R, Boido M, Vrijbloed JW, Fariello RG, Vercelli A. Synergistically Acting on Myostatin and Agrin Pathways Increases Neuromuscular Junction Stability and Endurance in Old Mice. Aging Dis 2024; 15:893-910. [PMID: 37548943 PMCID: PMC10917542 DOI: 10.14336/ad.2023.0713-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 07/13/2023] [Indexed: 08/08/2023] Open
Abstract
Sarcopenia is the primary cause of impaired motor performance in the elderly. The current prevailing approach to counteract such condition is increasing the muscle mass through inhibition of the myostatin system: however, this strategy only moderately improves muscular strength, not being able to sustain the innervation of the hypertrophic muscle per se, leading to a progressive worsening of motor performances. Thus, we proposed the administration of ActR-Fc-nLG3, a protein that combines the soluble activin receptor, a strong myostatin inhibitor, with the C-terminal agrin nLG3 domain. This compound has the potential of reinforcing neuro-muscular stability to the hypertrophic muscle. We previously demonstrated an enhancement of motor endurance and ACh receptor aggregation in young mice after ActR-Fc-nLG3 administration. Now we extended these observations by demonstrating that also in aged (2 years-old) mice, long-term administration of ActR-Fc-nLG3 increases in a sustained way both motor endurance and muscle strength, compared with ActR-Fc, a myostatin inhibitor, alone. Histological data demonstrate that the administration of this biological improves neuromuscular stability and fiber innervation maintenance, preventing muscle fiber atrophy and inducing only moderate hypertrophy. Moreover, at the postsynaptic site we observe an increased folding in the soleplate, a likely anatomical substrate for improved neurotransmission efficiency in the NMJ, that may lead to enhanced motor endurance. We suggest that ActR-Fc-nLG3 may become a valid option for treating sarcopenia and possibly other disorders of striatal muscles.
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Affiliation(s)
- Roberta Schellino
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
| | - Marina Boido
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
| | | | | | - Alessandro Vercelli
- Department of Neuroscience Rita Levi-Montalcini, University of Turin, Turin 10126, Italy
- Neuroscience Institute Cavalieri Ottolenghi, University of Turin, Orbassano, 10043 Italy
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Cisterna B, Malatesta M. Molecular and Structural Alterations of Skeletal Muscle Tissue Nuclei during Aging. Int J Mol Sci 2024; 25:1833. [PMID: 38339110 PMCID: PMC10855217 DOI: 10.3390/ijms25031833] [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: 12/27/2023] [Revised: 01/30/2024] [Accepted: 01/31/2024] [Indexed: 02/12/2024] Open
Abstract
Aging is accompanied by a progressive loss of skeletal muscle mass and strength. The mechanisms underlying this phenomenon are certainly multifactorial and still remain to be fully elucidated. Changes in the cell nucleus structure and function have been considered among the possible contributing causes. This review offers an overview of the current knowledge on skeletal muscle nuclei in aging, focusing on the impairment of nuclear pathways potentially involved in age-related muscle decline. In skeletal muscle two types of cells are present: fiber cells, constituting the contractile muscle mass and containing hundreds of myonuclei, and the satellite cells, i.e., the myogenic mononuclear stem cells occurring at the periphery of the fibers and responsible for muscle growth and repair. Research conducted on different experimental models and with different methodological approaches demonstrated that both the myonuclei and satellite cell nuclei of aged skeletal muscles undergo several structural and molecular alterations, affecting chromatin organization, gene expression, and transcriptional and post-transcriptional activities. These alterations play a key role in the impairment of muscle fiber homeostasis and regeneration, thus contributing to the age-related decrease in skeletal muscle mass and function.
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Affiliation(s)
| | - Manuela Malatesta
- Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Strada Le Grazie 8, 37134 Verona, Italy;
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Ehrlich M, Ehrlich KC, Lacey M, Baribault C, Sen S, Estève PO, Pradhan S. Epigenetics of Genes Preferentially Expressed in Dissimilar Cell Populations: Myoblasts and Cerebellum. EPIGENOMES 2024; 8:4. [PMID: 38390894 PMCID: PMC10885033 DOI: 10.3390/epigenomes8010004] [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: 12/12/2023] [Revised: 01/23/2024] [Accepted: 01/23/2024] [Indexed: 02/24/2024] Open
Abstract
While studying myoblast methylomes and transcriptomes, we found that CDH15 had a remarkable preference for expression in both myoblasts and cerebellum. To understand how widespread such a relationship was and its epigenetic and biological correlates, we systematically looked for genes with similar transcription profiles and analyzed their DNA methylation and chromatin state and accessibility profiles in many different cell populations. Twenty genes were expressed preferentially in myoblasts and cerebellum (Myob/Cbl genes). Some shared DNA hypo- or hypermethylated regions in myoblasts and cerebellum. Particularly striking was ZNF556, whose promoter is hypomethylated in expressing cells but highly methylated in the many cell populations that do not express the gene. In reporter gene assays, we demonstrated that its promoter's activity is methylation sensitive. The atypical epigenetics of ZNF556 may have originated from its promoter's hypomethylation and selective activation in sperm progenitors and oocytes. Five of the Myob/Cbl genes (KCNJ12, ST8SIA5, ZIC1, VAX2, and EN2) have much higher RNA levels in cerebellum than in myoblasts and displayed myoblast-specific hypermethylation upstream and/or downstream of their promoters that may downmodulate expression. Differential DNA methylation was associated with alternative promoter usage for Myob/Cbl genes MCF2L, DOK7, CNPY1, and ANK1. Myob/Cbl genes PAX3, LBX1, ZNF556, ZIC1, EN2, and VAX2 encode sequence-specific transcription factors, which likely help drive the myoblast and cerebellum specificity of other Myob/Cbl genes. This study extends our understanding of epigenetic/transcription associations related to differentiation and may help elucidate relationships between epigenetic signatures and muscular dystrophies or cerebellar-linked neuropathologies.
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Affiliation(s)
- Melanie Ehrlich
- Tulane Cancer Center, Hayward Human Genetics Center, Center for Bioinformatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
- Center for Bioinformatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Kenneth C Ehrlich
- Center for Bioinformatics and Genomics, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
| | - Michelle Lacey
- Department of Mathematics, Tulane University, New Orleans, LA 70118, USA
| | - Carl Baribault
- Information Technology, Tulane University, New Orleans, LA 70118, USA
| | - Sagnik Sen
- Genome Biology Division, New England Biolabs, Ipswich, MA 01938, USA
| | | | - Sriharsa Pradhan
- Genome Biology Division, New England Biolabs, Ipswich, MA 01938, USA
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Tannemaat MR, Huijbers MG, Verschuuren JJGM. Myasthenia gravis-Pathophysiology, diagnosis, and treatment. HANDBOOK OF CLINICAL NEUROLOGY 2024; 200:283-305. [PMID: 38494283 DOI: 10.1016/b978-0-12-823912-4.00026-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Myasthenia gravis (MG) is an autoimmune disease characterized by dysfunction of the neuromuscular junction resulting in skeletal muscle weakness. It is equally prevalent in males and females, but debuts at a younger age in females and at an older age in males. Ptosis, diplopia, facial bulbar weakness, and limb weakness are the most common symptoms. MG can be classified based on the presence of serum autoantibodies. Acetylcholine receptor (AChR) antibodies are found in 80%-85% of patients, muscle-specific kinase (MuSK) antibodies in 5%-8%, and <1% may have low-density lipoprotein receptor-related protein 4 (Lrp4) antibodies. Approximately 10% of patients are seronegative for antibodies binding the known disease-related antigens. In patients with AChR MG, 10%-20% have a thymoma, which is usually detected at the onset of the disease. Important differences between clinical presentation, treatment responsiveness, and disease mechanisms have been observed between these different serologic MG classes. Besides the typical clinical features and serologic testing, the diagnosis can be established with additional tests, including repetitive nerve stimulation, single fiber EMG, and the ice pack test. Treatment options for MG consist of symptomatic treatment (such as pyridostigmine), immunosuppressive treatment, or thymectomy. Despite the treatment with symptomatic drugs, steroid-sparing immunosuppressants, intravenous immunoglobulins, plasmapheresis, and thymectomy, a large proportion of patients remain chronically dependent on corticosteroids (CS). In the past decade, the number of treatment options for MG has considerably increased. Advances in the understanding of the pathophysiology have led to new treatment options targeting B or T cells, the complement cascade, the neonatal Fc receptor or cytokines. In the future, these new treatments are likely to reduce the chronic use of CS, diminish side effects, and decrease the number of patients with refractory disease.
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Affiliation(s)
- Martijn R Tannemaat
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
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Cao M, Liu WW, Maxwell S, Huda S, Webster R, Evoli A, Beeson D, Cossins JA, Vincent A. IgG1-3 MuSK Antibodies Inhibit AChR Cluster Formation, Restored by SHP2 Inhibitor, Despite Normal MuSK, DOK7, or AChR Subunit Phosphorylation. NEUROLOGY(R) NEUROIMMUNOLOGY & NEUROINFLAMMATION 2023; 10:e200147. [PMID: 37582613 PMCID: PMC10427144 DOI: 10.1212/nxi.0000000000200147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 06/07/2023] [Indexed: 08/17/2023]
Abstract
BACKGROUND AND OBJECTIVES Up to 50% of patients with myasthenia gravis (MG) without acetylcholine receptor antibodies (AChR-Abs) have antibodies to muscle-specific kinase (MuSK). Most MuSK antibodies (MuSK-Abs) are IgG4 and inhibit agrin-induced MuSK phosphorylation, leading to impaired clustering of AChRs at the developing or mature neuromuscular junction. However, IgG1-3 MuSK-Abs also exist in MuSK-MG patients, and their potential mechanisms have not been explored fully. METHODS C2C12 myotubes were exposed to MuSK-MG plasma IgG1-3 or IgG4, with or without purified agrin. MuSK, Downstream of Kinase 7 (DOK7), and βAChR were immunoprecipitated and their phosphorylation levels identified by immunoblotting. Agrin and agrin-independent AChR clusters were measured by immunofluorescence and AChR numbers by binding of 125I-α-bungarotoxin. Transcriptomic analysis was performed on treated myotubes. RESULTS IgG1-3 MuSK-Abs impaired AChR clustering without inhibiting agrin-induced MuSK phosphorylation. Moreover, the well-established pathway initiated by MuSK through DOK7, resulting in βAChR phosphorylation, was not impaired by MuSK-IgG1-3 and was agrin-independent. Nevertheless, the AChR clusters did not form, and both the number of AChR microclusters that precede full cluster formation and the myotube surface AChRs were reduced. Transcriptomic analysis did not throw light on the pathways involved. However, the SHP2 inhibitor, NSC-87877, increased the number of microclusters and led to fully formed AChR clusters. DISCUSSION MuSK-IgG1-3 is pathogenic but seems to act through a noncanonical pathway. Further studies should throw light on the mechanisms involved at the neuromuscular junction.
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Affiliation(s)
- Michelangelo Cao
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Wei-Wei Liu
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Susan Maxwell
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Saif Huda
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Richard Webster
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Amelia Evoli
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - David Beeson
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Judith A Cossins
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy
| | - Angela Vincent
- From the Nuffield Department of Clinical Neurosciences (M.C., W.W.L., S.M., R.W., D.B., J.A.C., A.V.), University of Oxford; Norfolk and Norwich University Hospital (M.C.); The Walton Centre NHS Foundation Trust (S.H.), Liverpool, United Kingdom; and Department of Neuroscience (A.E.), Catholic University, Rome, Italy.
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11
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Leng Y, Li X, Zheng F, Liu H, Wang C, Wang X, Liao Y, Liu J, Meng K, Yu J, Zhang J, Wang B, Tan Y, Liu M, Jia X, Li D, Li Y, Gu Z, Fan Y. Advances in In Vitro Models of Neuromuscular Junction: Focusing on Organ-on-a-Chip, Organoids, and Biohybrid Robotics. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2211059. [PMID: 36934404 DOI: 10.1002/adma.202211059] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Revised: 02/18/2023] [Indexed: 06/18/2023]
Abstract
The neuromuscular junction (NMJ) is a peripheral synaptic connection between presynaptic motor neurons and postsynaptic skeletal muscle fibers that enables muscle contraction and voluntary motor movement. Many traumatic, neurodegenerative, and neuroimmunological diseases are classically believed to mainly affect either the neuronal or the muscle side of the NMJ, and treatment options are lacking. Recent advances in novel techniques have helped develop in vitro physiological and pathophysiological models of the NMJ as well as enable precise control and evaluation of its functions. This paper reviews the recent developments in in vitro NMJ models with 2D or 3D cultures, from organ-on-a-chip and organoids to biohybrid robotics. Related derivative techniques are introduced for functional analysis of the NMJ, such as the patch-clamp technique, microelectrode arrays, calcium imaging, and stimulus methods, particularly optogenetic-mediated light stimulation, microelectrode-mediated electrical stimulation, and biochemical stimulation. Finally, the applications of the in vitro NMJ models as disease models or for drug screening related to suitable neuromuscular diseases are summarized and their future development trends and challenges are discussed.
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Affiliation(s)
- Yubing Leng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Xiaorui Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Fuyin Zheng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Hui Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Chunyan Wang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Xudong Wang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Yulong Liao
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Jiangyue Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Kaiqi Meng
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Jiaheng Yu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Jingyi Zhang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Binyu Wang
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Yingjun Tan
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Meili Liu
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Xiaoling Jia
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Deyu Li
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
| | - Yinghui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, 100094, China
| | - Zhongze Gu
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, Southeast University, Nanjing, 210096, China
| | - Yubo Fan
- Key Laboratory for Biomechanics and Mechanobiology of Ministry of Education, Beijing Advanced Innovation Center for Biomedical Engineering, School of Biological Science and Medical Engineering, and with the School of Engineering Medicine, Beihang University, Beijing, 100083, China
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12
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Liao X, Wang Y, Lai X, Wang S. The role of Rapsyn in neuromuscular junction and congenital myasthenic syndrome. BIOMOLECULES & BIOMEDICINE 2023; 23:772-784. [PMID: 36815443 PMCID: PMC10494853 DOI: 10.17305/bb.2022.8641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/02/2023] [Accepted: 02/17/2023] [Indexed: 02/23/2023]
Abstract
Rapsyn, an intracellular scaffolding protein associated with the postsynaptic membranes in the neuromuscular junction (NMJ), is critical for nicotinic acetylcholine receptor clustering and maintenance. Therefore, Rapsyn is essential to the NMJ formation and maintenance, and Rapsyn mutant is one of the reasons causing the pathogenies of congenital myasthenic syndrome (CMS). In addition, there is little research on Rapsyn in the central nervous system (CNS). In this review, the role of Rapsyn in the NMJ formation and the mutation of Rapsyn leading to CMS will be reviewed separately and sequentially. Finally, the potential function of Rapsyn is prospected.
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Affiliation(s)
- Xufeng Liao
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Yingxing Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
| | - Xinsheng Lai
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
| | - Shunqi Wang
- Institute of Life Science and School of Life Sciences, Nanchang University, Nanchang, China
- School of Basic Medical Sciences, Nanchang University, Nanchang, China
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13
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Saito A, Matsui S, Chino A, Sato S, Takeshita N. Discovery and pharmacological characterization of novel positive allosteric modulators acting on skeletal muscle-type nicotinic acetylcholine receptors. Biochem Biophys Res Commun 2023; 668:27-34. [PMID: 37235916 DOI: 10.1016/j.bbrc.2023.04.103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Revised: 04/21/2023] [Accepted: 04/27/2023] [Indexed: 05/28/2023]
Abstract
Skeletal muscle-type nicotinic acetylcholine receptors (m-nAChRs) are ligand-gated ion channels that open after activation by ACh and whose signals cause muscle contraction. Defects in neurotransmission are reported in disorders such as myasthenia gravis (MG) and congenital myasthenia syndromes (CMS). Although treatments for these disorders exist, therapies which significantly increase muscle strength have yet to be reported. Positive allosteric modulators (PAMs), which promote ACh signaling through AChRs, are expected to be promising therapeutic agents. In this study, we identified an m-nAChR PAM called AS3513678 by high-throughput screening using human myotube cells and modified it to obtain novel compounds (AS3566987 and AS3580239) that showed even stronger PAM activity. AS3580239 caused a leftward shift in the ACh concentration-response curve and was 14.0-fold potent at 10 μM compared with vehicle. Next, we examined the effect of AS3580239 on electrically-induced isometric contraction of the extensor digitorum longus (EDL) muscle in wild-type (WT) and MG model rats. AS3580239 enhanced EDL muscle contraction in both WT and MG model rats at 30 μM. These data suggest that AS3580239 improved neurotransmission and enhanced muscle strength. Thus, m-nAChR PAMs may be a useful treatment for neuromuscular diseases.
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Affiliation(s)
- Asako Saito
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan.
| | - Shigeo Matsui
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Ayaka Chino
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Shota Sato
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
| | - Nobuaki Takeshita
- Astellas Pharma Inc, 21, Miyukigaoka, Tsukuba, Ibaraki, 305-8585, Japan
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14
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Deschenes MR, Mifsud MK, Patek LG, Flannery RE. Cellular and Subcellular Characteristics of Neuromuscular Junctions in Muscles with Disparate Duty Cycles and Myofiber Profiles. Cells 2023; 12:cells12030361. [PMID: 36766702 PMCID: PMC9913535 DOI: 10.3390/cells12030361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/10/2023] [Accepted: 01/16/2023] [Indexed: 01/20/2023] Open
Abstract
The neuromuscular system accounts for a large portion (~40%) of whole body mass while enabling body movement, including physical work and exercise. At the core of this system is the neuromuscular junction (NMJ) which is the vital synapse transducing electrical impulses from the motor neurons to their post-synaptic myofibers. Recent findings suggest that subcellular features (active zones) of the NMJ are distinctly sensitive to changes in activity relative to cellular features (nerve terminal branches, vesicles, receptors) of the NMJ. In the present investigation, muscles with different recruitment patterns, functions, and myofiber type profiles (soleus, plantaris, extensor digitorum longus [EDL]) were studied to quantify both cellular and subcellular NMJ characteristics along with myofiber type profiles. Results indicated that, in general, dimensions of subcellular components of NMJs mirrored cellular NMJ features when examining inter-muscle NMJ architecture. Typically, it was noted that the NMJs of the soleus, with its most pronounced recruitment pattern, were larger (p < 0.05) than NMJs of less recruited muscles. Moreover, it was revealed that myofiber size did not dictate NMJ size as soleus muscles displayed the smallest fibers (p < 0.05) while the plantaris muscles exhibited the largest fibers. In total, these data show that activity determines the size of NMJs and that generally, size dimensions of cellular and subcellular components of the NMJ are matched, and that the size of NMJs and their underlying myofibers are uncoupled.
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Affiliation(s)
- Michael R. Deschenes
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, VA 23187, USA
- Program in Neuroscience, College of William & Mary, Williamsburg, VA 23187, USA
- Correspondence: ; Tel.: +1-757-221-2778
| | - Mia K. Mifsud
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, VA 23187, USA
| | - Leah G. Patek
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, VA 23187, USA
| | - Rachel E. Flannery
- Department of Kinesiology & Health Sciences, College of William & Mary, Williamsburg, VA 23187, USA
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15
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Alignment of Skeletal Muscle Cells Facilitates Acetylcholine Receptor Clustering and Neuromuscular Junction Formation with Co-Cultured Human iPSC-Derived Motor Neurons. Cells 2022; 11:cells11233760. [PMID: 36497020 PMCID: PMC9738074 DOI: 10.3390/cells11233760] [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: 09/21/2022] [Revised: 11/04/2022] [Accepted: 11/20/2022] [Indexed: 11/27/2022] Open
Abstract
In vitro neuromuscular junction (NMJ) models are powerful tools for studying neuromuscular disorders. Although linearly patterned culture surfaces have been reported to be useful for the formation of in vitro NMJ models using mouse motor neuron (MNs) and skeletal muscle (SkM) myotubes, it is unclear how the linearly patterned culture surface increases acetylcholine receptor (AChR) clustering, one of the steps in the process of NMJ formation, and whether this increases the in vitro NMJ formation efficiency of co-cultured human MNs and SkM myotubes. In this study, we investigated the effects of a linearly patterned culture surface on AChR clustering in myotubes and examined the possible mechanism of the increase in AChR clustering using gene expression analysis, as well as the effects of the patterned surface on the efficiency of NMJ formation between co-cultured human SkM myotubes and human iPSC-derived MNs. Our results suggest that better differentiation of myotubes on the patterned surface, compared to the flat surface, induced gene expression of integrin α7 and AChR ε-subunit, thereby increasing AChR clustering. Furthermore, we found that the number of NMJs between human SkM cells and MNs increased upon co-culture on the linearly patterned surface, suggesting the usefulness of the patterned surface for creating in vitro human NMJ models.
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16
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Gros K, Matkovič U, Parato G, Miš K, Luin E, Bernareggi A, Sciancalepore M, Marš T, Lorenzon P, Pirkmajer S. Neuronal Agrin Promotes Proliferation of Primary Human Myoblasts in an Age-Dependent Manner. Int J Mol Sci 2022; 23:ijms231911784. [PMID: 36233091 PMCID: PMC9570459 DOI: 10.3390/ijms231911784] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2022] [Revised: 09/06/2022] [Accepted: 09/22/2022] [Indexed: 12/02/2022] Open
Abstract
Neuronal agrin, a heparan sulphate proteoglycan secreted by the α-motor neurons, promotes the formation and maintenance of the neuromuscular junction by binding to Lrp4 and activating muscle-specific kinase (MuSK). Neuronal agrin also promotes myogenesis by enhancing differentiation and maturation of myotubes, but its effect on proliferating human myoblasts, which are often considered to be unresponsive to agrin, remains unclear. Using primary human myoblasts, we determined that neuronal agrin induced transient dephosphorylation of ERK1/2, while c-Abl, STAT3, and focal adhesion kinase were unresponsive. Gene silencing of Lrp4 and MuSK markedly reduced the BrdU incorporation, suggesting the functional importance of the Lrp4/MuSK complex for myoblast proliferation. Acute and chronic treatments with neuronal agrin increased the proliferation of human myoblasts in old donors, but they did not affect the proliferation of myoblasts in young donors. The C-terminal fragment of agrin which lacks the Lrp4-binding site and cannot activate MuSK had a similar age-dependent effect, indicating that the age-dependent signalling pathways activated by neuronal agrin involve the Lrp4/MuSK receptor complex as well as an Lrp4/MuSK-independent pathway which remained unknown. Collectively, our results highlight an age-dependent role for neuronal agrin in promoting the proliferation of human myoblasts.
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Affiliation(s)
- Katarina Gros
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Urška Matkovič
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Giulia Parato
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Katarina Miš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Elisa Luin
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Annalisa Bernareggi
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Marina Sciancalepore
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
| | - Tomaž Marš
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Paola Lorenzon
- Department of Life Sciences, University of Trieste, 34127 Trieste, Italy
- The B.R.A.I.N. Centre for Neuroscience, University of Trieste, 34127 Trieste, Italy
- Correspondence: (P.L.); (S.P.)
| | - Sergej Pirkmajer
- Institute of Pathophysiology, Faculty of Medicine, University of Ljubljana, 1000 Ljubljana, Slovenia
- Correspondence: (P.L.); (S.P.)
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17
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SMN controls neuromuscular junction integrity through U7 snRNP. Cell Rep 2022; 40:111393. [PMID: 36130491 PMCID: PMC9533342 DOI: 10.1016/j.celrep.2022.111393] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2022] [Revised: 07/18/2022] [Accepted: 08/30/2022] [Indexed: 01/26/2023] Open
Abstract
The neuromuscular junction (NMJ) is an essential synapse whose loss is a key hallmark of the neurodegenerative disease spinal muscular atrophy (SMA). Here, we show that activity of the SMA-determining SMN protein in the assembly of U7 small nuclear ribonucleoprotein (snRNP)—which functions in the 3′-end processing of replication-dependent histone mRNAs—is required for NMJ integrity. Co-expression of U7-specific Lsm10 and Lsm11 proteins selectively enhances U7 snRNP assembly, corrects histone mRNA processing defects, and rescues key structural and functional abnormalities of neuromuscular pathology in SMA mice—including NMJ denervation, decreased synaptic transmission, and skeletal muscle atrophy. Furthermore, U7 snRNP dysfunction drives selective loss of the synaptic organizing protein Agrin at NMJs innervating vulnerable muscles of SMA mice. These findings reveal a direct contribution of U7 snRNP dysfunction to neuromuscular pathology in SMA and suggest a role for histone gene regulation in maintaining functional synaptic connections between motor neurons and muscles. NMJ denervation is a hallmark of SMA. Through selective restoration of U7 snRNP biogenesis in SMA mice, Tisdale et al. reveal a role for SMN-mediated U7 snRNP assembly and histone mRNA processing in controlling NMJ integrity through Agrin expression, uncovering RNA-mediated disease mechanisms and linking U7 function to neuromuscular development.
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18
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ALS mutations in both human skeletal muscle and motoneurons differentially affects neuromuscular junction integrity and function. Biomaterials 2022; 289:121752. [DOI: 10.1016/j.biomaterials.2022.121752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Revised: 07/05/2022] [Accepted: 08/16/2022] [Indexed: 11/19/2022]
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19
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Hughes DC, Baehr LM, Waddell DS, Sharples AP, Bodine SC. Ubiquitin Ligases in Longevity and Aging Skeletal Muscle. Int J Mol Sci 2022; 23:7602. [PMID: 35886949 PMCID: PMC9315556 DOI: 10.3390/ijms23147602] [Citation(s) in RCA: 4] [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: 06/22/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 12/07/2022] Open
Abstract
The development and prevalence of diseases associated with aging presents a global health burden on society. One hallmark of aging is the loss of proteostasis which is caused in part by alterations to the ubiquitin-proteasome system (UPS) and lysosome-autophagy system leading to impaired function and maintenance of mass in tissues such as skeletal muscle. In the instance of skeletal muscle, the impairment of function occurs early in the aging process and is dependent on proteostatic mechanisms. The UPS plays a pivotal role in degradation of misfolded and aggregated proteins. For the purpose of this review, we will discuss the role of the UPS system in the context of age-related loss of muscle mass and function. We highlight the significant role that E3 ubiquitin ligases play in the turnover of key components (e.g., mitochondria and neuromuscular junction) essential to skeletal muscle function and the influence of aging. In addition, we will briefly discuss the contribution of the UPS system to lifespan. By understanding the UPS system as part of the proteostasis network in age-related diseases and disorders such as sarcopenia, new discoveries can be made and new interventions can be developed which will preserve muscle function and maintain quality of life with advancing age.
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Affiliation(s)
- David C. Hughes
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (L.M.B.); (S.C.B.)
| | - Leslie M. Baehr
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (L.M.B.); (S.C.B.)
| | - David S. Waddell
- Department of Biology, University of North Florida, Jacksonville, FL 32224, USA;
| | - Adam P. Sharples
- Institute for Physical Performance, Norwegian School of Sport Sciences (NiH), 0863 Oslo, Norway;
| | - Sue C. Bodine
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA 52242, USA; (L.M.B.); (S.C.B.)
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20
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Control of CRK-RAC1 activity by the miR-1/206/133 miRNA family is essential for neuromuscular junction function. Nat Commun 2022; 13:3180. [PMID: 35676269 PMCID: PMC9178026 DOI: 10.1038/s41467-022-30778-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 05/07/2022] [Indexed: 11/08/2022] Open
Abstract
Formation and maintenance of neuromuscular junctions (NMJs) are essential for skeletal muscle function, allowing voluntary movements and maintenance of the muscle tone, thereby preventing atrophy. Generation of NMJs depends on the interaction of motor neurons with skeletal muscle fibers, which initiates a cascade of regulatory events that is essential for patterning of acetylcholine receptor (AChR) clusters at specific sites of the sarcolemma. Here, we show that muscle-specific miRNAs of the miR-1/206/133 family are crucial regulators of a signaling cascade comprising DOK7-CRK-RAC1, which is critical for stabilization and anchoring of postsynaptic AChRs during NMJ development and maintenance. We describe that posttranscriptional repression of CRK by miR-1/206/133 is essential for balanced activation of RAC1. Failure to adjust RAC1 activity severely compromises NMJ function, causing respiratory failure in neonates and neuromuscular symptoms in adult mice. We conclude that miR-1/206/133 serve a specific function for NMJs but are dispensable for skeletal muscle development. The miR-1/133/206 gene family codes for the most abundant microRNAs in striated muscles. Here, Klockner et al show that inactivation of all family members in skeletal muscle prevents formation of normal neuromuscular junctions due to increased expression of the adaptor protein CRK.
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21
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Ding Q, Kesavan K, Lee KM, Wimberger E, Robertson T, Gill M, Power D, Chang J, Fard AT, Mar JC, Henderson RD, Heggie S, McCombe PA, Jeffree RL, Colditz MJ, Hilliard MA, Ng DCH, Steyn FJ, Phillips WD, Wolvetang EJ, Ngo ST, Noakes PG. Impaired signaling for neuromuscular synaptic maintenance is a feature of Motor Neuron Disease. Acta Neuropathol Commun 2022; 10:61. [PMID: 35468848 PMCID: PMC9040261 DOI: 10.1186/s40478-022-01360-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 11/17/2022] Open
Abstract
A central event in the pathogenesis of motor neuron disease (MND) is the loss of neuromuscular junctions (NMJs), yet the mechanisms that lead to this event in MND remain to be fully elucidated. Maintenance of the NMJ relies upon neural agrin (n-agrin) which, when released from the nerve terminal, activates the postsynaptic Muscle Specific Kinase (MuSK) signaling complex to stabilize clusters of acetylcholine receptors. Here, we report that muscle from MND patients has an increased proportion of slow fibers and muscle fibers with smaller diameter. Muscle cells cultured from MND biopsies failed to form large clusters of acetylcholine receptors in response to either non-MND human motor axons or n-agrin. Furthermore, levels of expression of MuSK, and MuSK-complex components: LRP4, Caveolin-3, and Dok7 differed between muscle cells cultured from MND patients compared to those from non-MND controls. To our knowledge, this is the first time a fault in the n-agrin-LRP4-MuSK signaling pathway has been identified in muscle from MND patients. Our results highlight the n-agrin-LRP4-MuSK signaling pathway as a potential therapeutic target to prolong muscle function in MND.
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22
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Uemura T, Suzuki-Kouyama E, Kawase S, Kurihara T, Yasumura M, Yoshida T, Fukai S, Yamazaki M, Fei P, Abe M, Watanabe M, Sakimura K, Mishina M, Tabuchi K. Neurexins play a crucial role in cerebellar granule cell survival by organizing autocrine machinery for neurotrophins. Cell Rep 2022; 39:110624. [PMID: 35385735 DOI: 10.1016/j.celrep.2022.110624] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 02/22/2022] [Accepted: 03/15/2022] [Indexed: 01/22/2023] Open
Abstract
Neurexins (NRXNs) are key presynaptic cell adhesion molecules that regulate synapse formation and function via trans-synaptic interaction with postsynaptic ligands. Here, we generate cerebellar granule cell (CGC)-specific Nrxn triple-knockout (TKO) mice for complete deletion of all NRXNs. Unexpectedly, most CGCs die in these mice, and this requirement for NRXNs for cell survival is reproduced in cultured CGCs. The axons of cultured Nrxn TKO CGCs that are not in contact with a postsynaptic structure show defects in the formation of presynaptic protein clusters and in action-potential-induced Ca2+ influxes. These cells also show impaired secretion of depolarization-induced, fluorescence-tagged brain-derived neurotrophic factor (BDNF) from their axons, and the cell-survival defect is rescued by the application of BDNF. These results suggest that CGC survival is maintained by autocrine neurotrophic factors and that NRXNs organize the presynaptic protein clusters and the autocrine neurotrophic-factor secretory machinery independent of contact with postsynaptic ligands.
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Affiliation(s)
- Takeshi Uemura
- Division of Gene Research, Research Center for Advanced Science, Shinshu University, Nagano 390-8621, Japan; Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; JST CREST, Saitama 332-0012, Japan.
| | - Emi Suzuki-Kouyama
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST CREST, Saitama 332-0012, Japan
| | - Shiori Kawase
- Division of Gene Research, Research Center for Advanced Science, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST CREST, Saitama 332-0012, Japan
| | - Taiga Kurihara
- Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan
| | - Misato Yasumura
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Department of Anatomy and Neuroscience, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
| | - Tomoyuki Yoshida
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Department of Molecular Neuroscience, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama 930-0194, Japan; JST PRESTO, Saitama 332-0012, Japan
| | - Shuya Fukai
- JST CREST, Saitama 332-0012, Japan; Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Maya Yamazaki
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Peng Fei
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Manabu Abe
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan; Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Faculty of Medicine, Hokkaido University, Sapporo 060-8638, Japan
| | - Kenji Sakimura
- Department of Cellular Neurobiology, Brain Research Institute, Niigata University, Niigata 951-8585, Japan; Department of Animal Model Development, Brain Research Institute, Niigata University, Niigata 951-8585, Japan
| | - Masayoshi Mishina
- Department of Molecular Neurobiology and Pharmacology, Graduate School of Medicine, University of Tokyo, Tokyo 113-0033, Japan; Brain Science Laboratory, Research Organization of Science and Technology, Ritsumeikan University, Shiga 525-8577, Japan
| | - Katsuhiko Tabuchi
- Institute for Biomedical Sciences, Interdisciplinary Cluster for Cutting Edge Research, Shinshu University, Nagano 390-8621, Japan; Department of Molecular and Cellular Physiology, Institute of Medicine, Academic Assembly, Shinshu University, Nagano 390-8621, Japan; JST PRESTO, Saitama 332-0012, Japan.
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23
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Kaplan MM, Flucher BE. Counteractive and cooperative actions of muscle β-catenin and CaV1.1 during early neuromuscular synapse formation. iScience 2022; 25:104025. [PMID: 35340430 PMCID: PMC8941212 DOI: 10.1016/j.isci.2022.104025] [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: 10/15/2021] [Revised: 01/07/2022] [Accepted: 03/01/2022] [Indexed: 11/29/2022] Open
Abstract
Activity-dependent calcium signals in developing muscle play a crucial role in neuromuscular junction (NMJ) formation. However, its downstream effectors and interactions with other regulators of pre- and postsynaptic differentiation are poorly understood. Here, we demonstrate that the skeletal muscle calcium channel CaV1.1 and β-catenin interact in various ways to control NMJ development. They differentially regulate nerve branching and presynaptic innervation patterns during the initial phase of NMJ formation. Conversely, they cooperate in regulating postsynaptic AChR clustering, synapse formation, and the proper organization of muscle fibers in mouse diaphragm. CaV1.1 does not directly regulate β-catenin expression but differentially controls the activity of its transcriptional co-regulators TCF/Lef and YAP. These findings suggest a crosstalk between CaV1.1 and β-catenin in the activity-dependent transcriptional regulation of genes involved in specific pre- and postsynaptic aspects of NMJ formation. Neuromuscular junction formation requires either muscle calcium or β-catenin signaling Complementary actions of CaV1.1 and β-catenin control presynaptic innervation patterns Parallel actions of CaV1.1 and β-catenin are crucial for postsynaptic AChR clustering Loss of CaV1.1 differentially regulates activity of β-catenin targets TCF/Lef and YAP
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Affiliation(s)
- Mehmet Mahsum Kaplan
- Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
- Corresponding author
| | - Bernhard E. Flucher
- Department of Physiology and Medical Physics, Medical University Innsbruck, 6020 Innsbruck, Austria
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24
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Budayeva HG, Sengupta-Ghosh A, Phu L, Moffat JG, Ayalon G, Kirkpatrick DS. Phosphoproteome Profiling of the Receptor Tyrosine Kinase MuSK Identifies Tyrosine Phosphorylation of Rab GTPases. Mol Cell Proteomics 2022; 21:100221. [PMID: 35227894 PMCID: PMC8972003 DOI: 10.1016/j.mcpro.2022.100221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 11/16/2022] Open
Abstract
Muscle-specific receptor tyrosine kinase (MuSK) agonist antibodies were developed 2 decades ago to explore the benefits of receptor activation at the neuromuscular junction. Unlike agrin, the endogenous agonist of MuSK, agonist antibodies function independently of its coreceptor low-density lipoprotein receptor–related protein 4 to delay the onset of muscle denervation in mouse models of ALS. Here, we performed dose–response and time-course experiments on myotubes to systematically compare site-specific phosphorylation downstream of each agonist. Remarkably, both agonists elicited similar intracellular responses at known and newly identified MuSK signaling components. Among these was inducible tyrosine phosphorylation of multiple Rab GTPases that was blocked by MuSK inhibition. Importantly, mutation of this site in Rab10 disrupts association with its effector proteins, molecule interacting with CasL 1/3. Together, these data provide in-depth characterization of MuSK signaling, describe two novel MuSK inhibitors, and expose phosphorylation of Rab GTPases downstream of receptor tyrosine kinase activation in myotubes. Different agonists of muscle-specific kinase (MuSK) elicit similar phosphoprofiles. MuSK activation induces tyrosine phosphorylation of several Rab GTPases. MuSK inhibitors diminish receptor signaling, including phosphorylation on Rab10 Y6. Mutation of Rab10 Y6 disrupts its association with Mical adaptor proteins.
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Affiliation(s)
- Hanna G Budayeva
- Microchemistry, Proteomics, and Lipidomics Department, Genentech, Inc, South San Francisco, California, USA.
| | | | - Lilian Phu
- Microchemistry, Proteomics, and Lipidomics Department, Genentech, Inc, South San Francisco, California, USA
| | - John G Moffat
- Biochemical and Cellular Pharmacology and Computational Drug Design, Genentech, Inc, South San Francisco, California, USA
| | - Gai Ayalon
- Neuroscience Department, Genentech, Inc, South San Francisco, California, USA
| | - Donald S Kirkpatrick
- Microchemistry, Proteomics, and Lipidomics Department, Genentech, Inc, South San Francisco, California, USA.
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25
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Raffa P, Easler M, Urciuolo A. Three-dimensional in vitro models of neuromuscular tissue. Neural Regen Res 2022; 17:759-766. [PMID: 34472462 PMCID: PMC8530117 DOI: 10.4103/1673-5374.322447] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/08/2021] [Accepted: 05/18/2021] [Indexed: 12/13/2022] Open
Abstract
Skeletal muscle is a dynamic tissue in which homeostasis and function are guaranteed by a very defined three-dimensional organization of myofibers in respect to other non-muscular components, including the extracellular matrix and the nervous network. In particular, communication between myofibers and the nervous system is essential for the overall correct development and function of the skeletal muscle. A wide range of chronic, acute and genetic-based human pathologies that lead to the alteration of muscle function are associated with modified preservation of the fine interaction between motor neurons and myofibers at the neuromuscular junction. Recent advancements in the development of in vitro models for human skeletal muscle have shown that three-dimensionality and integration of multiple cell types are both key parameters required to unveil pathophysiological relevant phenotypes. Here, we describe recent achievement reached in skeletal muscle modeling which used biomaterials for the generation of three-dimensional constructs of myotubes integrated with motor neurons.
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Affiliation(s)
- Paolo Raffa
- Institute of Pediatric Research IRP, Padova, Italy
| | - Maria Easler
- Institute of Pediatric Research IRP, Padova, Italy
| | - Anna Urciuolo
- Institute of Pediatric Research IRP, Padova, Italy
- Molecular Medicine Department, University of Padova, Padova, Italy
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26
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Gemza A, Barresi C, Proemer J, Hatami J, Lazaridis M, Herbst R. Internalization of Muscle-Specific Kinase Is Increased by Agrin and Independent of Kinase-Activity, Lrp4 and Dynamin. Front Mol Neurosci 2022; 15:780659. [PMID: 35370548 PMCID: PMC8965242 DOI: 10.3389/fnmol.2022.780659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 02/21/2022] [Indexed: 11/13/2022] Open
Abstract
Muscle-specific kinase (MuSK) is a receptor tyrosine kinase absolutely required for neuromuscular junction formation. MuSK is activated by binding of motor neuron-derived Agrin to low-density lipoprotein receptor related protein 4 (Lrp4), which forms a complex with MuSK. MuSK activation and downstream signaling are critical events during the development of the neuromuscular junction. Receptor tyrosine kinases are commonly internalized upon ligand binding and crosstalk between endocytosis and signaling has been implicated. To extend our knowledge about endocytosis of synaptic proteins and its role during postsynaptic differentiation at the neuromuscular junction, we studied the stability and internalization of Lrp4, MuSK and acetylcholine receptors (AChRs) in response to Agrin. We provide evidence that MuSK but not Lrp4 internalization is increased by Agrin stimulation. MuSK kinase-activity is not sufficient to induce MuSK internalization and the absence of Lrp4 has no effect on MuSK endocytosis. Moreover, MuSK internalization and signaling are unaffected by the inhibition of Dynamin suggesting that MuSK endocytosis uses a non-conventional pathway and is not required for MuSK-dependent downstream signaling.
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Affiliation(s)
- Anna Gemza
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Cinzia Barresi
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Jakob Proemer
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Jasmin Hatami
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Margarita Lazaridis
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
| | - Ruth Herbst
- Center for Pathophysiology, Infectiology and Immunology, Medical University of Vienna, Vienna, Austria
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27
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Li J, Fredericks M, Cannell M, Wang K, Sako D, Maguire MC, Grenha R, Liharska K, Krishnan L, Bloom T, Belcheva EP, Martinez PA, Castonguay R, Keates S, Alexander MJ, Choi H, Grinberg AV, Pearsall RS, Oh P, Kumar R, Suragani RN. ActRIIB:ALK4-Fc alleviates muscle dysfunction and comorbidities in murine models of neuromuscular disorders. J Clin Invest 2021; 131:138634. [PMID: 33586684 DOI: 10.1172/jci138634] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 12/29/2020] [Indexed: 01/06/2023] Open
Abstract
Patients with neuromuscular disorders suffer from a lack of treatment options for skeletal muscle weakness and disease comorbidities. Here, we introduce as a potential therapeutic agent a heterodimeric ligand-trapping fusion protein, ActRIIB:ALK4-Fc, which comprises extracellular domains of activin-like kinase 4 (ALK4) and activin receptor type IIB (ActRIIB), a naturally occurring pair of type I and II receptors belonging to the TGF-β superfamily. By surface plasmon resonance (SPR), ActRIIB:ALK4-Fc exhibited a ligand binding profile distinctly different from that of its homodimeric variant ActRIIB-Fc, sequestering ActRIIB ligands known to inhibit muscle growth but not trapping the vascular regulatory ligand bone morphogenetic protein 9 (BMP9). ActRIIB:ALK4-Fc and ActRIIB-Fc administered to mice exerted differential effects - concordant with SPR results - on vessel outgrowth in a retinal explant assay. ActRIIB:ALK4-Fc induced a systemic increase in muscle mass and function in wild-type mice and in murine models of Duchenne muscular dystrophy (DMD), amyotrophic lateral sclerosis (ALS), and disuse atrophy. Importantly, ActRIIB:ALK4-Fc improved neuromuscular junction abnormalities in murine models of DMD and presymptomatic ALS and alleviated acute muscle fibrosis in a DMD model. Furthermore, in combination therapy ActRIIB:ALK4-Fc increased the efficacy of antisense oligonucleotide M12-PMO on dystrophin expression and skeletal muscle endurance in an aged DMD model. ActRIIB:ALK4-Fc shows promise as a therapeutic agent, alone or in combination with dystrophin rescue therapy, to alleviate muscle weakness and comorbidities of neuromuscular disorders.
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Affiliation(s)
- Jia Li
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | - Kathryn Wang
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | - Dianne Sako
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | - Rosa Grenha
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | - Troy Bloom
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | | | | | - Sarah Keates
- Acceleron Pharma Inc., Cambridge, Massachusetts, USA
| | | | - Hyunwoo Choi
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona, USA
| | | | | | - Paul Oh
- Department of Neurobiology, Barrow Neurological Institute, Phoenix, Arizona, USA
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28
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Matta JA, Gu S, Davini WB, Bredt DS. Nicotinic acetylcholine receptor redux: Discovery of accessories opens therapeutic vistas. Science 2021; 373:373/6556/eabg6539. [PMID: 34385370 DOI: 10.1126/science.abg6539] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The neurotransmitter acetylcholine (ACh) acts in part through a family of nicotinic ACh receptors (nAChRs), which mediate diverse physiological processes including muscle contraction, neurotransmission, and sensory transduction. Pharmacologically, nAChRs are responsible for tobacco addiction and are targeted by medicines for hypertension and dementia. Nicotinic AChRs were the first ion channels to be isolated. Recent studies have identified molecules that control nAChR biogenesis, trafficking, and function. These nAChR accessories include protein and chemical chaperones as well as auxiliary subunits. Whereas some factors act on many nAChRs, others are receptor specific. Discovery of these regulatory mechanisms is transforming nAChR research in cells and tissues ranging from central neurons to spinal ganglia to cochlear hair cells. Nicotinic AChR-specific accessories also enable drug discovery on high-confidence targets for psychiatric, neurological, and auditory disorders.
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Affiliation(s)
| | | | - Weston B Davini
- Neuroscience Discovery, Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, CA 92121, USA
| | - David S Bredt
- Neuroscience Discovery, Janssen Pharmaceutical Companies of Johnson & Johnson, San Diego, CA 92121, USA.
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29
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Barbosa GK, Jacob CDS, Rodrigues MP, Rocha LC, Pimentel Neto J, Ciena AP. Morphological Changes in the Motor Endplate and in the Belly Muscle Induced by Previous Static Stretching to the Climbing Protocol. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2021; 27:1-9. [PMID: 34294184 DOI: 10.1017/s1431927621012253] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Static stretching provides benefits to the range of motion, modulates intramuscular connective tissue, and is incorporated into warm-up exercises. In this study, we present the effects in the motor endplate and belly muscle resulting from previous static stretching to climbing training. Twenty-four adult male Wistar rats were divided into four groups (n = 6 each): Sedentary (Sed), Climbing (Clb), Static stretching (Ss), and Static stretching prior to climbing (Ssc). The animals (Clb, Ss, and Ssc groups) were subjected to a training protocol 3×/week for 8 weeks, and the Ssc group was subjected to the Ss and Clb protocols in the same session. Samples from the animals were processed for immunostaining, histochemistry, and light microscopy. The Clb group presented a higher motor endplate; the Ss group presented no changes in the motor endplate; and the Ssc group demonstrated a higher compactness. We concluded that static stretching prior to the climbing protocol maintained the density of the motor endplate and increased the compactness of the neuromuscular junction structure. Also, there was a reduction in the myofibers’ diameter (Type I and IIa), an increase in myofibrillar densities (Type I and IIx, and total), and the reorganization of the myonuclei and the interstitium.
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Affiliation(s)
- Gabriela K Barbosa
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
| | - Carolina Dos S Jacob
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
| | - Mariana P Rodrigues
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
| | - Lara C Rocha
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
| | - Jurandyr Pimentel Neto
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
| | - Adriano P Ciena
- Department of Physical Activity, Laboratory of Morphology and Physical Activity - LAMAF, Institute of Biosciences (IB), São Paulo State University - UNESP, Rio Claro13506-900, SP, Brazil
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30
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Vergoossen DLE, Keo A, Mahfouz A, Huijbers MG. Timing and localization of myasthenia gravis-related gene expression. Eur J Neurosci 2021; 54:5574-5585. [PMID: 34228850 PMCID: PMC8457065 DOI: 10.1111/ejn.15382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 06/01/2021] [Accepted: 07/01/2021] [Indexed: 11/29/2022]
Abstract
Myasthenia gravis (MG) is an acquired autoimmune disorder caused by autoantibodies binding acetylcholine receptors (AChR), muscle‐specific kinase (MuSK), agrin or low‐density lipoprotein receptor‐related protein 4 (Lrp4). These autoantibodies inhibit neuromuscular transmission by blocking the function of these proteins and thereby cause fluctuating skeletal muscle weakness. Several reports suggest that these autoantibodies might also affect the central nervous system (CNS) in MG patients. A comprehensive overview of the timing and localization of the expression of MG‐related antigens in other organs is currently lacking. To investigate the spatio‐temporal expression of MG‐related genes outside skeletal muscle, we used in silico tools to assess public expression databases. Acetylcholine esterase, nicotinic AChR α1 subunit, agrin, collagen Q, downstream of kinase‐7, Lrp4, MuSK and rapsyn were included as MG‐related genes because of their well‐known involvement in either congenital or autoimmune MG. We investigated expression of MG‐related genes in (1) all human tissues using GTEx data, (2) specific brain regions, (3) neurodevelopmental stages, and (4) cell types using datasets from the Allen Institute for Brain Sciences. MG‐related genes show heterogenous spatio‐temporal expression patterns in the human body as well as in the CNS. For each of these genes, several (new) tissues, brain areas and cortical cell types with (relatively) high expression were identified suggesting a potential role for these genes outside skeletal muscle. The possible presence of MG‐related antigens outside skeletal muscle suggests that autoimmune MG, congenital MG or treatments targeting the same proteins may affect MG‐related protein function in other organs.
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Affiliation(s)
- Dana L E Vergoossen
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Arlin Keo
- Leiden Computational Biology Center, Leiden University Medical Center, Leiden, The Netherlands.,Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
| | - Ahmed Mahfouz
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Leiden Computational Biology Center, Leiden University Medical Center, Leiden, The Netherlands.,Delft Bioinformatics Lab, Delft University of Technology, Delft, The Netherlands
| | - Maartje G Huijbers
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.,Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
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31
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Zhou X, Vachon C, Cizeron M, Romatif O, Bülow HE, Jospin M, Bessereau JL. The HSPG syndecan is a core organizer of cholinergic synapses. J Cell Biol 2021; 220:212450. [PMID: 34213535 PMCID: PMC8258370 DOI: 10.1083/jcb.202011144] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 04/13/2021] [Accepted: 05/26/2021] [Indexed: 12/15/2022] Open
Abstract
The extracellular matrix has emerged as an active component of chemical synapses regulating synaptic formation, maintenance, and homeostasis. The heparan sulfate proteoglycan (HSPG) syndecans are known to regulate cellular and axonal migration in the brain. They are also enriched at synapses, but their synaptic functions remain more elusive. Here, we show that SDN-1, the sole orthologue of syndecan in C. elegans, is absolutely required for the synaptic clustering of homomeric α7-like acetylcholine receptors (AChRs) and regulates the synaptic content of heteromeric AChRs. SDN-1 is concentrated at neuromuscular junctions (NMJs) by the neurally secreted synaptic organizer Ce-Punctin/MADD-4, which also activates the transmembrane netrin receptor DCC. Those cooperatively recruit the FARP and CASK orthologues that localize α7-like-AChRs at cholinergic NMJs through physical interactions. Therefore, SDN-1 stands at the core of the cholinergic synapse organization by bridging the extracellular synaptic determinants to the intracellular synaptic scaffold that controls the postsynaptic receptor content.
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Affiliation(s)
- Xin Zhou
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Camille Vachon
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Mélissa Cizeron
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Océane Romatif
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Hannes E Bülow
- Department of Genetics and Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, NY
| | - Maëlle Jospin
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
| | - Jean-Louis Bessereau
- Université de Lyon, Université Claude Bernard Lyon 1, Centre National de la Recherche Scientifique Unite Mixte de Recherche 5310, Institut National de la Santé et de la Recherche Médicale U1217, Institut NeuroMyoGène, Lyon, France
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Tsai LK, Chen IH, Chao CC, Hsueh HW, Chen HH, Huang YH, Weng RW, Lai TY, Tsai YC, Tsao YP, Chen SL. Autoantibody of NRIP, a novel AChR-interacting protein, plays a detrimental role in myasthenia gravis. J Cachexia Sarcopenia Muscle 2021; 12:665-676. [PMID: 33773096 PMCID: PMC8200423 DOI: 10.1002/jcsm.12697] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 01/30/2021] [Accepted: 02/10/2021] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Nuclear receptor interaction protein (NRIP) co-localizes with acetylcholine receptor (AChR) at the neuromuscular junction (NMJ), and NRIP deficiency causes aberrant NMJ architecture. However, the normal physiological and pathophysiological roles of NRIP in NMJ are still unclear. METHODS We investigated the co-localization and interaction of NRIP with AChR-associated proteins using immunofluorescence and immunoprecipitation assay, respectively. The binding affinity of AChR-associated proteins was analysed in muscle-restricted NRIP knockout mice and NRIP knockout muscle cells (C2C12). We further collected the sera from 43 patients with myasthenia gravis (MG), an NMJ disorder. The existence and features of anti-NRIP autoantibody in sera were studied using Western blot and epitope mapping. RESULTS NRIP co-localized with AChR, rapsyn and α-actinin 2 (ACTN2) in gastrocnemius muscles of mice; and α-bungarotoxin (BTX) pull-down assay revealed NRIP with rapsyn and ACTN2 in complexes from muscle tissues and cells. NRIP directly binds with α subunit of AChR (AChRα) in vitro and in vivo to affect the binding affinity of AChR with rapsyn and rapsyn with ACTN2. In 43 patients with MG (age, 58.4 ± 14.5 years; female, 55.8%), we detected six of them (14.0%) having anti-NRIP autoantibody. The presence of anti-NRIP autoantibody correlated with a more severe type of MG when AChR autoantibody existed (P = 0.011). The higher the titre of anti-NRIP autoantibody, the more severe MG severity (P = 0.032). The main immunogenic region is likely on the IQ motif of NRIP. We also showed the IgG subclass of anti-NRIP autoantibody mainly to be IgG1. CONCLUSIONS NRIP is a novel AChRα binding protein and involves structural NMJ formation, which acts as a scaffold to stabilize AChR-rapsyn-ACTN2 complexes. Anti-NRIP autoantibody is a novel autoantibody in MG and plays a detrimental role in MG with the coexistence of anti-AChR autoantibody.
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Affiliation(s)
- Li-Kai Tsai
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan.,Department of Neurology, National Taiwan University Hospital, Hsinchu Branch, Hsinchu, Taiwan
| | - I-Hsin Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Chi-Chao Chao
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Hsueh-Wen Hsueh
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Hsin-Hsiung Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yun-Hsin Huang
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Rong-Wei Weng
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Tzu-Yun Lai
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Yi-Chieh Tsai
- Department of Neurology, National Taiwan University Hospital, Taipei, Taiwan
| | - Yeou-Ping Tsao
- Department of Ophthalmology, Mackay Memorial Hospital, Taipei, Taiwan
| | - Show-Li Chen
- Graduate Institute of Microbiology, College of Medicine, National Taiwan University, Taipei, Taiwan
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Stoklund Dittlau K, Krasnow EN, Fumagalli L, Vandoorne T, Baatsen P, Kerstens A, Giacomazzi G, Pavie B, Rossaert E, Beckers J, Sampaolesi M, Van Damme P, Van Den Bosch L. Human motor units in microfluidic devices are impaired by FUS mutations and improved by HDAC6 inhibition. Stem Cell Reports 2021; 16:2213-2227. [PMID: 33891869 PMCID: PMC8452598 DOI: 10.1016/j.stemcr.2021.03.029] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2020] [Revised: 03/23/2021] [Accepted: 03/25/2021] [Indexed: 12/13/2022] Open
Abstract
Neuromuscular junctions (NMJs) ensure communication between motor neurons (MNs) and muscle; however, in MN disorders, such as amyotrophic lateral sclerosis (ALS), NMJs degenerate resulting in muscle atrophy. The aim of this study was to establish a versatile and reproducible in vitro model of a human motor unit to investigate the effects of ALS-causing mutations. Therefore, we generated a co-culture of human induced pluripotent stem cell (iPSC)-derived MNs and human primary mesoangioblast-derived myotubes in microfluidic devices. A chemotactic and volumetric gradient facilitated the growth of MN neurites through microgrooves resulting in the interaction with myotubes and the formation of NMJs. We observed that ALS-causing FUS mutations resulted in reduced neurite outgrowth as well as an impaired neurite regrowth upon axotomy. NMJ numbers were likewise reduced in the FUS-ALS model. Interestingly, the selective HDAC6 inhibitor, Tubastatin A, improved the neurite outgrowth, regrowth, and NMJ morphology, prompting HDAC6 inhibition as a potential therapeutic strategy for ALS. Human motor units with functional NMJs can be generated using microfluidic devices FUS-ALS motor units display impaired neurite regrowth, outgrowth and NMJ numbers HDAC6 inhibition alleviate FUS-ALS motor unit pathology in vitro
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Affiliation(s)
- Katarina Stoklund Dittlau
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Emily N Krasnow
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Laura Fumagalli
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Tijs Vandoorne
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Pieter Baatsen
- VIB, Center for Brain & Disease Research, Research Group Molecular Neurobiology, Leuven, Belgium; KU Leuven - University of Leuven, VIB Bio Imaging Core, Leuven, Belgium
| | - Axelle Kerstens
- VIB, Center for Brain & Disease Research, Research Group Molecular Neurobiology, Leuven, Belgium; KU Leuven - University of Leuven, VIB Bio Imaging Core, Leuven, Belgium
| | - Giorgia Giacomazzi
- KU Leuven - University of Leuven, Department of Development and Regeneration, Stem Cell and Developmental Biology, Leuven, Belgium
| | - Benjamin Pavie
- VIB, Center for Brain & Disease Research, Research Group Molecular Neurobiology, Leuven, Belgium; KU Leuven - University of Leuven, VIB Bio Imaging Core, Leuven, Belgium
| | - Elisabeth Rossaert
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Jimmy Beckers
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium
| | - Maurilio Sampaolesi
- KU Leuven - University of Leuven, Department of Development and Regeneration, Stem Cell and Developmental Biology, Leuven, Belgium
| | - Philip Van Damme
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium; University Hospitals Leuven, Department of Neurology, Leuven, Belgium
| | - Ludo Van Den Bosch
- KU Leuven - University of Leuven, Department of Neurosciences, Experimental Neurology, and Leuven Brain Institute, Leuven, Belgium; VIB, Center for Brain & Disease Research, Laboratory of Neurobiology, Leuven, Belgium.
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Pinto CG, Leite APS, Sartori AA, Tibúrcio FC, Barraviera B, Junior RSF, Filadelpho AL, de Carvalho SC, Matheus SMM. Heterologous fibrin biopolymer associated to a single suture stitch enables the return of neuromuscular junction to its mature pattern after peripheral nerve injury. Injury 2021; 52:731-737. [PMID: 33902866 DOI: 10.1016/j.injury.2020.10.070] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Revised: 09/26/2020] [Accepted: 10/15/2020] [Indexed: 02/07/2023]
Abstract
Denervation leads to severe atrophy of neuromuscular junction (NMJ) structure including decrease of the expression of fundamental proteins. Up to now, conventional suture has been the gold standard method used to correct this injury. Fibrin sealant is one of the alternatives proposed to optimize this method. This study verified if the association of fibrin sealant - Heterologous Fibrin Biopolymer (HFB) and a single suture stitch promotes return of morphology and NMJ structure to mature pattern after peripheral nerve injury. Forty Wistar rats were distributed into 4 groups: Sham-Control (SC), Denervated-Control (DC), Suture-Lesion (SL) and Suture-Lesion + HFB (SFS). In SC group only the right sciatic nerve identification was done. In DC, SL and SFS groups fixation of nerve stumps on musculature immediately after neurotmesis was performed. After seven days, stump reconnection with 3 stitches in SL and a single stitch associated with HFB in SFS were done. After sixty days right soleus muscles were prepared for nicotinic acetylcholine receptors (nAChRs) and nerve terminal confocal analyses, and for nAChRs (α1, ε e γ), S100, Agrin, LRP-4, MMP-3, Rapsyn western blotting analyses. SC group presented normal morphology. In DC group it was observed flattening of NMJ, fragmentation of nAChRs and tangled nerve terminals. The majority of the parameters of SL and SFS groups presented values in between SC and DC groups. There was an increase of relative planar area in these groups (SL and SFS) highlighting that there was less nAChRs fragmentation and the values of protein expression showed return of nAChRs to mature pattern. Use of HFB associated with a single suture stitch decreased surgical time, minimized suture injuries, did not alter nerve regeneration and presented potential to reestablish the NMJ apparatus. These consolidated results encourage surgeons to develop future clinical trials to install definitively this new approach both for reconstructive surgery and neurosurgery.
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Affiliation(s)
- Carina Guidi Pinto
- Graduate Program in Surgery and Translational Medicine, Medical School, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil; Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - Ana Paula Silveira Leite
- Graduate Program in Surgery and Translational Medicine, Medical School, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil; Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - Arthur Alves Sartori
- Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - Felipe Cantore Tibúrcio
- Graduate Program in Surgery and Translational Medicine, Medical School, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil; Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - Benedito Barraviera
- Center for the Studies of Venoms and Venomous Animals (CEVAP), São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - Rui Seabra Ferreira Junior
- Center for the Studies of Venoms and Venomous Animals (CEVAP), São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | - André Luis Filadelpho
- Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil
| | | | - Selma Maria Michelin Matheus
- Department of Structural and Functional Biology (Anatomy Sector), Institute of Biosciences, São Paulo State University (Unesp), Botucatu, São Paulo, Brazil.
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Abstract
The function of neuronal circuits relies on the properties of individual neuronal cells and their synapses. We propose that a substantial degree of synapse formation and function is instructed by molecular codes resulting from transcriptional programmes. Recent studies on the Neurexin protein family and its ligands provide fundamental insight into how synapses are assembled and remodelled, how synaptic properties are specified and how single gene mutations associated with neurodevelopmental and psychiatric disorders might modify the operation of neuronal circuits and behaviour. In this Review, we first summarize insights into Neurexin function obtained from various model organisms. We then discuss the mechanisms and logic of the cell type-specific regulation of Neurexin isoforms, in particular at the level of alternative mRNA splicing. Finally, we propose a conceptual framework for how combinations of synaptic protein isoforms act as 'senders' and 'readers' to instruct synapse formation and the acquisition of cell type-specific and synapse-specific functional properties.
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36
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Barrantes FJ. Possible implications of dysregulated nicotinic acetylcholine receptor diffusion and nanocluster formation in myasthenia gravis. Neural Regen Res 2021; 16:242-246. [PMID: 32859770 PMCID: PMC7896218 DOI: 10.4103/1673-5374.290880] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Myasthenia gravis is a rare and invalidating disease affecting the neuromuscular junction of voluntary muscles. The classical form of this autoimmune disease is characterized by the presence of antibodies against the most abundant protein in the neuromuscular junction, the nicotinic acetylcholine receptor. Other variants of the disease involve autoimmune attack of non-receptor scaffolding proteins or enzymes essential for building or maintaining the integrity of this peripheral synapse. This review summarizes the participation of the above proteins in building the neuromuscular junction and the destruction of this cholinergic synapse by autoimmune aggression in myasthenia gravis. The review also covers the application of a powerful biophysical technique, superresolution optical microscopy, to image the nicotinic receptor in live cells and follow its motional dynamics. The hypothesis is entertained that anomalous nanocluster formation by antibody crosslinking may lead to accelerated endocytic internalization and elevated turnover of the receptor, as observed in myasthenia gravis.
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37
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Karmouch J, Delers P, Semprez F, Soyed N, Areias J, Bélanger G, Ravel-Chapuis A, Dobbertin A, Jasmin BJ, Legay C. AChR β-Subunit mRNAs Are Stabilized by HuR in a Mouse Model of Congenital Myasthenic Syndrome With Acetylcholinesterase Deficiency. Front Mol Neurosci 2020; 13:568171. [PMID: 33362463 PMCID: PMC7757417 DOI: 10.3389/fnmol.2020.568171] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 08/13/2020] [Indexed: 11/13/2022] Open
Abstract
Collagen Q (COLQ) is a specific collagen that anchors acetylcholinesterase (AChE) in the synaptic cleft of the neuromuscular junction. So far, no mutation has been identified in the ACHE human gene but over 50 different mutations in the COLQ gene are causative for a congenital myasthenic syndrome (CMS) with AChE deficiency. Mice deficient for COLQ mimic most of the functional deficit observed in CMS patients. At the molecular level, a striking consequence of the absence of COLQ is an increase in the levels of acetylcholine receptor (AChR) mRNAs and proteins in vivo and in vitro in murine skeletal muscle cells. Here, we decipher the mechanisms that drive AChR mRNA upregulation in cultured muscle cells deficient for COLQ. We show that the levels of AChR β-subunit mRNAs are post-transcriptionally regulated by an increase in their stability. We demonstrate that this process results from an activation of p38 MAPK and the cytoplasmic translocation of the nuclear RNA-binding protein human antigen R (HuR) that interacts with the AU-rich element located within AChR β-subunit transcripts. This HuR/AChR transcript interaction induces AChR β-subunit mRNA stabilization and occurs at a specific stage of myogenic differentiation. In addition, pharmacological drugs that modulate p38 activity cause parallel modifications of HuR protein and AChR β-subunit levels. Thus, our study provides new insights into the signaling pathways that are regulated by ColQ-deficiency and highlights for the first time a role for HuR and p38 in mRNA stability in a model of congenital myasthenic syndrome.
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Affiliation(s)
- Jennifer Karmouch
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Perrine Delers
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Fannie Semprez
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Nouha Soyed
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Julie Areias
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
| | - Guy Bélanger
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | | | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Claire Legay
- CNRS UMR 8003, Université de Paris, Sorbonne Paris Cité, Paris, France
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Zelada D, Bermedo-García F, Collao N, Henríquez JP. Motor function recovery: deciphering a regenerative niche at the neuromuscular synapse. Biol Rev Camb Philos Soc 2020; 96:752-766. [PMID: 33336525 PMCID: PMC7986695 DOI: 10.1111/brv.12675] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 11/20/2020] [Accepted: 11/25/2020] [Indexed: 12/13/2022]
Abstract
The coordinated movement of many organisms relies on efficient nerve–muscle communication at the neuromuscular junction (NMJ), a peripheral synapse composed of a presynaptic motor axon terminal, a postsynaptic muscle specialization, and non‐myelinating terminal Schwann cells. NMJ dysfunctions are caused by traumatic spinal cord or peripheral nerve injuries as well as by severe motor pathologies. Compared to the central nervous system, the peripheral nervous system displays remarkable regenerating abilities; however, this capacity is limited by the denervation time frame and depends on the establishment of permissive regenerative niches. At the injury site, detailed information is available regarding the cells, molecules, and mechanisms involved in nerve regeneration and repair. However, a regenerative niche at the final functional step of peripheral motor innervation, i.e. at the mature neuromuscular synapse, has not been deciphered. In this review, we integrate classic and recent evidence describing the cells and molecules that could orchestrate a dynamic ecosystem to accomplish successful NMJ regeneration. We propose that such a regenerative niche must ensure at least two fundamental steps for successful NMJ regeneration: the proper arrival of incoming regenerating axons to denervated postsynaptic muscle domains, and the resilience of those postsynaptic domains, in morphological and functional terms. We here describe and combine the main cellular and molecular responses involved in each of these steps as potential targets to help successful NMJ regeneration.
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Affiliation(s)
- Diego Zelada
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Francisca Bermedo-García
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Nicolás Collao
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
| | - Juan P Henríquez
- Neuromuscular Studies Laboratory (NeSt Lab), Department of Cell Biology, Faculty of Biological Sciences, Center for Advanced Microscopy (CMA Bio-Bio), Universidad de Concepción, Casilla 160-C, Concepción, Chile
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Petrany MJ, Swoboda CO, Sun C, Chetal K, Chen X, Weirauch MT, Salomonis N, Millay DP. Single-nucleus RNA-seq identifies transcriptional heterogeneity in multinucleated skeletal myofibers. Nat Commun 2020; 11:6374. [PMID: 33311464 PMCID: PMC7733460 DOI: 10.1038/s41467-020-20063-w] [Citation(s) in RCA: 195] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 11/09/2020] [Indexed: 02/06/2023] Open
Abstract
While the majority of cells contain a single nucleus, cell types such as trophoblasts, osteoclasts, and skeletal myofibers require multinucleation. One advantage of multinucleation can be the assignment of distinct functions to different nuclei, but comprehensive interrogation of transcriptional heterogeneity within multinucleated tissues has been challenging due to the presence of a shared cytoplasm. Here, we utilized single-nucleus RNA-sequencing (snRNA-seq) to determine the extent of transcriptional diversity within multinucleated skeletal myofibers. Nuclei from mouse skeletal muscle were profiled across the lifespan, which revealed the presence of distinct myonuclear populations emerging in postnatal development as well as aging muscle. Our datasets also provided a platform for discovery of genes associated with rare specialized regions of the muscle cell, including markers of the myotendinous junction and functionally validated factors expressed at the neuromuscular junction. These findings reveal that myonuclei within syncytial muscle fibers possess distinct transcriptional profiles that regulate muscle biology.
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Affiliation(s)
- Michael J Petrany
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Casey O Swoboda
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Chengyi Sun
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Kashish Chetal
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Xiaoting Chen
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
| | - Matthew T Weirauch
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Center for Autoimmune Genomics and Etiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Nathan Salomonis
- Division of Biomedical Informatics, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Douglas P Millay
- Division of Molecular Cardiovascular Biology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA.
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH, USA.
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Bao Z, Cui C, Chow SKH, Qin L, Wong RMY, Cheung WH. AChRs Degeneration at NMJ in Aging-Associated Sarcopenia-A Systematic Review. Front Aging Neurosci 2020; 12:597811. [PMID: 33362532 PMCID: PMC7759742 DOI: 10.3389/fnagi.2020.597811] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Accepted: 11/19/2020] [Indexed: 12/16/2022] Open
Abstract
Sarcopenia is an aging process with a decline of skeletal muscle mass and function, which is a challenging public health problem with reduced quality of life in patients. The endplate, the post-synaptic part of the neuromuscular junction (NMJ), occupies 0.1% of the myofiber surface area only, but is composed of millions of acetylcholine receptors (AChRs) that are efficient in binding to acetylcholine (ACh) and triggering skeletal muscle contraction. This systematic review aims to examine aging-associated alterations of post-synaptic AChRs, including morphology, function and related gene expression. A systematic literature search was conducted in PubMed, Embase and Web of Science with relevant keywords by two independent reviewers. Original pre-clinical and clinical studies regarding AChRs changes during aging with available full text and written in English were included. Information was extracted from the included studies for further review. In total, 30 articles were included. Various parameters assessing AChRs alterations by radioassay, immunofluorescence, electrophysiology and mechanical test were reported. Endplate fragmentation and denervation were common in old skeletal muscles during aging. To ensure efficient NMJ transmission and force generation, type I or IIb muscle fibers tended to have increased ACh quanta releasing after electrical stimulations, while type IIa muscle fibers tended to have stronger binding between ACh and AChRs, but the overall function of AChRs was reduced during aging. Alterations of AChRs area depended on muscle type, species and the progress of muscle atrophy and type I muscles fibers tended to demonstrate enlarging AChRs areas. Myogenic regulator factors (MRFs) can regulate the expression of AChRs subunits, while decreased MRF4 may lead to expression changes of AChRs subunits during aging. Sarcoglycan-α can delay low-density lipoprotein receptor-related protein 4 (LRP4) degradation. This protein was increased in old muscles but still cannot suppress the degradation of LRP4. Investigating the role of these AChRs-related genes in the process of aging may provide a potential target to treat sarcopenia.
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Affiliation(s)
- Zhengyuan Bao
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Can Cui
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Simon Kwoon-Ho Chow
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| | - Ling Qin
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Ronald Man Yeung Wong
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China
| | - Wing-Hoi Cheung
- Department of Orthopaedics and Traumatology, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.,The CUHK-ACC Space Medicine Centre on Health Maintenance of Musculoskeletal System, The Chinese University of Hong Kong Shenzhen Research Institute, Shenzhen, China
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41
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Barbeau S, Tahraoui-Bories J, Legay C, Martinat C. Building neuromuscular junctions in vitro. Development 2020; 147:147/22/dev193920. [PMID: 33199350 DOI: 10.1242/dev.193920] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The neuromuscular junction (NMJ) has been the model of choice to understand the principles of communication at chemical synapses. Following groundbreaking experiments carried out over 60 years ago, many studies have focused on the molecular mechanisms underlying the development and physiology of these synapses. This Review summarizes the progress made to date towards obtaining faithful models of NMJs in vitro We provide a historical approach discussing initial experiments investigating NMJ development and function from Xenopus to mice, the creation of chimeric co-cultures, in vivo approaches and co-culture methods from ex vivo and in vitro derived cells, as well as the most recent developments to generate human NMJs. We discuss the benefits of these techniques and the challenges to be addressed in the future for promoting our understanding of development and human disease.
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Affiliation(s)
- Susie Barbeau
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, F-75006 Paris, France
| | - Julie Tahraoui-Bories
- INSERM/UEPS UMR 861, Paris Saclay Université, I-STEM, 91100 Corbeil-Essonnes, France
| | - Claire Legay
- Université de Paris, CNRS, SPPIN - Saints-Pères Paris Institute for the Neurosciences, F-75006 Paris, France
| | - Cécile Martinat
- INSERM/UEPS UMR 861, Paris Saclay Université, I-STEM, 91100 Corbeil-Essonnes, France
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Ng SY, Ljubicic V. Recent insights into neuromuscular junction biology in Duchenne muscular dystrophy: Impacts, challenges, and opportunities. EBioMedicine 2020; 61:103032. [PMID: 33039707 PMCID: PMC7648118 DOI: 10.1016/j.ebiom.2020.103032] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/28/2020] [Accepted: 09/11/2020] [Indexed: 12/13/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is the most common and relentless form of muscular dystrophy. The pleiotropic effects of dystrophin deficiency include remarkable impacts on neuromuscular junction (NMJ) structure and function. Some of these alterations contribute to the severe muscle wasting and weakness that distinguish DMD, while others attempt to compensate for them. Experimental approaches that correct NMJ biology in pre-clinical models of DMD attenuate disease progression and improve functional outcomes, which suggests that targeting the NMJ may be an effective therapeutic strategy for DMD patients. The objectives of this review are to 1) survey the distinctions in NMJ structure, function, and gene expression in the dystrophic context as compared to the healthy condition, and 2) summarize the efforts, opportunities and challenges to correct NMJ biology in DMD. This information will expand our basic understanding of neuromuscular biology and may be useful for designing novel NMJ-targeted drug or behavioural strategies to mitigate the dystrophic pathology and other disorders of the neuromuscular system.
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Affiliation(s)
- Sean Y Ng
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada
| | - Vladimir Ljubicic
- Department of Kinesiology, McMaster University, Hamilton L8S 4L8, Ontario, Canada.
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Lin SS, Hsieh TL, Liou GG, Li TN, Lin HC, Chang CW, Wu HY, Yao CK, Liu YW. Dynamin-2 Regulates Postsynaptic Cytoskeleton Organization and Neuromuscular Junction Development. Cell Rep 2020; 33:108310. [DOI: 10.1016/j.celrep.2020.108310] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 09/23/2020] [Accepted: 10/05/2020] [Indexed: 11/30/2022] Open
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Zhao Y, Peng HB. Roles of tyrosine kinases and phosphatases in the formation and dispersal of acetylcholine receptor clusters. Neurosci Lett 2020; 733:135054. [PMID: 32428606 DOI: 10.1016/j.neulet.2020.135054] [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: 02/27/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 10/24/2022]
Abstract
The formation of acetylcholine receptor (AChR) clusters at the postsynaptic muscle membrane in response to motor innervation is a key event in the development of the neuromuscular junction. The synaptic AChR clustering process is initiated by motor axon-released agrin, which activates a tyrosine kinase-based signaling pathway to cause AChR aggregation. In cultured muscle cells, AChR clustering is elicited by diverse nonneural signals, and this process is also mediated by tyrosine kinases. Conversely, the formation of new AChR clusters induced by innervation or nonneural stimuli is unfailingly associated with the dispersal of pre-existing AChR clusters, and this process is mediated by tyrosine phosphatases. In this review, we address how local kinase activation leads to global phosphatase action in muscle. More specifically, we discuss the roles of Src kinase and the SH2 domain-containing tyrosine phosphatase Shp-2 in establishing a regenerative mechanism to propagate the AChR cluster dispersing signal extrasynaptically and in defining the boundary of cluster formation subsynaptically.
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Affiliation(s)
- Yang Zhao
- Division of Life Science, the Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region.
| | - H Benjamin Peng
- Division of Life Science, the Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong Special Administrative Region; College of Life Science, National Tsing Hua University, Hsinchu, Taiwan, ROC.
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Takamori M. Myasthenia Gravis: From the Viewpoint of Pathogenicity Focusing on Acetylcholine Receptor Clustering, Trans-Synaptic Homeostasis and Synaptic Stability. Front Mol Neurosci 2020; 13:86. [PMID: 32547365 PMCID: PMC7272578 DOI: 10.3389/fnmol.2020.00086] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 04/28/2020] [Indexed: 12/18/2022] Open
Abstract
Myasthenia gravis (MG) is a disease of the postsynaptic neuromuscular junction (NMJ) where nicotinic acetylcholine (ACh) receptors (AChRs) are targeted by autoantibodies. Search for other pathogenic antigens has detected the antibodies against muscle-specific tyrosine kinase (MuSK) and low-density lipoprotein-related protein 4 (Lrp4), both causing pre- and post-synaptic impairments. Agrin is also suspected as a fourth pathogen. In a complex NMJ organization centering on MuSK: (1) the Wnt non-canonical pathway through the Wnt-Lrp4-MuSK cysteine-rich domain (CRD)-Dishevelled (Dvl, scaffold protein) signaling acts to form AChR prepatterning with axonal guidance; (2) the neural agrin-Lrp4-MuSK (Ig1/2 domains) signaling acts to form rapsyn-anchored AChR clusters at the innervated stage of muscle; (3) adaptor protein Dok-7 acts on MuSK activation for AChR clustering from “inside” and also on cytoskeleton to stabilize AChR clusters by the downstream effector Sorbs1/2; (4) the trans-synaptic retrograde signaling contributes to the presynaptic organization via: (i) Wnt-MuSK CRD-Dvl-β catenin-Slit 2 pathway; (ii) Lrp4; and (iii) laminins. The presynaptic Ca2+ homeostasis conditioning ACh release is modified by autoreceptors such as M1-type muscarinic AChR and A2A adenosine receptors. The post-synaptic structure is stabilized by: (i) laminin-network including the muscle-derived agrin; (ii) the extracellular matrix proteins (including collagen Q/perlecan and biglycan which link to MuSK Ig1 domain and CRD); and (iii) the dystrophin-associated glycoprotein complex. The study on MuSK ectodomains (Ig1/2 domains and CRD) recognized by antibodies suggested that the MuSK antibodies were pathologically heterogeneous due to their binding to multiple functional domains. Focussing one of the matrix proteins, biglycan which functions in the manner similar to collagen Q, our antibody assay showed the negative result in MG patients. However, the synaptic stability may be impaired by antibodies against MuSK ectodomains because of the linkage of biglycan with MuSK Ig1 domain and CRD. The pathogenic diversity of MG is discussed based on NMJ signaling molecules.
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Vanhaesebrouck AE, Webster R, Maxwell S, Rodriguez Cruz PM, Cossins J, Wickens J, Liu WW, Cetin H, Cheung J, Ramjattan H, Palace J, Beeson D. β2-Adrenergic receptor agonists ameliorate the adverse effect of long-term pyridostigmine on neuromuscular junction structure. Brain 2020; 142:3713-3727. [PMID: 31633155 PMCID: PMC6892641 DOI: 10.1093/brain/awz322] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/04/2019] [Accepted: 08/26/2019] [Indexed: 01/07/2023] Open
Abstract
Acetylcholine receptor deficiency is the most common form of the congenital myasthenic syndromes, a heterogeneous collection of genetic disorders of neuromuscular transmission characterized by fatiguable muscle weakness. Most patients with acetylcholine receptor deficiency respond well to acetylcholinesterase inhibitors; however, in some cases the efficacy of acetylcholinesterase inhibitors diminishes over time. Patients with acetylcholine receptor deficiency can also benefit from the addition of a β2-adrenergic receptor agonist to their medication. The working mechanism of β2-adrenergic agonists in myasthenic patients is not fully understood. Here, we report the long-term follow-up for the addition of β2-adrenergic agonists for a cohort of patients with acetylcholine receptor deficiency on anticholinesterase medication that demonstrates a sustained quantitative improvement. Coincidently we used a disease model to mirror the treatment of acetylcholine receptor deficiency, and demonstrate improved muscle fatigue, improved neuromuscular transmission and improved synaptic structure resulting from the addition of the β2-adrenergic agonist salbutamol to the anticholinesterase medication pyridostigmine. Following an initial improvement in muscle fatiguability, a gradual decline in the effect of pyridostigmine was observed in mice treated with pyridostigmine alone (P < 0.001). Combination therapy with pyridostigmine and salbutamol counteracted this decline (P < 0.001). Studies of compound muscle action potential decrement at high nerve stimulation frequencies (P < 0.05) and miniature end-plate potential amplitude analysis (P < 0.01) showed an improvement in mice following combination therapy, compared to pyridostigmine monotherapy. Pyridostigmine alone reduced postsynaptic areas (P < 0.001) and postsynaptic folding (P < 0.01). Combination therapy increased postsynaptic area (P < 0.001) and promoted the formation of postsynaptic junctional folds (P < 0.001), in particular in fast-twitch muscles. In conclusion, we demonstrate for the first time how the improvement seen in patients from adding salbutamol to their medication can be explained in an experimental model of acetylcholine receptor deficiency, the most common form of congenital myasthenic syndrome. Salbutamol enhances neuromuscular junction synaptic structure by counteracting the detrimental effects of long-term acetylcholinesterase inhibitors on the postsynaptic neuromuscular junction. The results have implications for both autoimmune and genetic myasthenias where anticholinesterase medication is a standard treatment.
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Affiliation(s)
- An E Vanhaesebrouck
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Richard Webster
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Susan Maxwell
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Pedro M Rodriguez Cruz
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK.,Department of Clinical Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Judith Cossins
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - James Wickens
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Wei-Wei Liu
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Hakan Cetin
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Jonathan Cheung
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
| | - Hayley Ramjattan
- Paediatric Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - Jacqueline Palace
- Department of Clinical Neurology, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DU, UK
| | - David Beeson
- Neurosciences Group, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, Oxford, OX3 9DS, UK
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Abstract
Thirty to fifty percent of patients with acetylcholine receptor (AChR) antibody (Ab)-negative myasthenia gravis (MG) have Abs to muscle specific kinase (MuSK) and are referred to as having MuSK-MG. MuSK is a 100 kD single-pass post-synaptic transmembrane receptor tyrosine kinase crucial to the development and maintenance of the neuromuscular junction. The Abs in MuSK-MG are predominantly of the IgG4 immunoglobulin subclass. MuSK-MG differs from AChR-MG, in exhibiting more focal muscle involvement, including neck, shoulder, facial and bulbar-innervated muscles, as well as wasting of the involved muscles. MuSK-MG is highly associated with the HLA DR14-DQ5 haplotype and occurs predominantly in females with onset in the fourth decade of life. Some of the standard treatments of AChR-MG have been found to have limited effectiveness in MuSK-MG, including thymectomy and cholinesterase inhibitors. Therefore, current treatment involves immunosuppression, primarily by corticosteroids. In addition, patients respond especially well to B cell depletion agents, e.g., rituximab, with long-term remissions. Future treatments will likely derive from the ongoing analysis of the pathogenic mechanisms underlying this disease, including histologic and physiologic studies of the neuromuscular junction in patients as well as information derived from the development and study of animal models of the disease.
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Affiliation(s)
| | - David P. Richman
- Department of Neurology, University of California, Davis, Davis, CA, United States
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48
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Multiple MuSK signaling pathways and the aging neuromuscular junction. Neurosci Lett 2020; 731:135014. [PMID: 32353380 DOI: 10.1016/j.neulet.2020.135014] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 04/23/2020] [Accepted: 04/24/2020] [Indexed: 12/16/2022]
Abstract
The neuromuscular junction (NMJ) is the vehicle for fast, reliable and robust communication between motor neuron and muscle. The unparalleled accessibility of this synapse to morphological, electrophysiological and genetic analysis has yielded an in depth understanding of many molecular components mediating its formation, maturation and stability. However, key questions surrounding the signaling pathways mediating these events and how they play out across the lifetime of the synapse remain unanswered. Such information is critical since the NMJ is necessary for normal movement and is compromised in several settings including myasthenia gravis, amyotrophic lateral sclerosis (ALS), spinal muscular atrophy (SMA), muscular dystrophy, sarcopenia and aging. Muscle specific kinase (MuSK) is a central player in most if not all contexts of NMJ formation and stability. However, elucidating the function of this receptor in this range of settings is challenging since MuSK participates in at least three signaling pathways: as a tyrosine kinase-dependent receptor for agrin-LRP4 and Wnts; and, as a kinase-independent BMP co-receptor. Here we focus on NMJ stability during aging and discuss open questions regarding the molecular mechanisms that govern active maintenance of the NMJ, with emphasis on MuSK and the potential role of its multiple signaling contexts.
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Fan J, Ji T, Wang K, Huang J, Wang M, Manning L, Dong X, Shi Y, Zhang X, Shao Z, Colón-Ramos DA. A muscle-epidermis-glia signaling axis sustains synaptic specificity during allometric growth in Caenorhabditis elegans. eLife 2020; 9:55890. [PMID: 32255430 PMCID: PMC7164957 DOI: 10.7554/elife.55890] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 04/05/2020] [Indexed: 02/06/2023] Open
Abstract
Synaptic positions underlie precise circuit connectivity. Synaptic positions can be established during embryogenesis and sustained during growth. The mechanisms that sustain synaptic specificity during allometric growth are largely unknown. We performed forward genetic screens in C. elegans for regulators of this process and identified mig-17, a conserved ADAMTS metalloprotease. Proteomic mass spectrometry, cell biological and genetic studies demonstrate that MIG-17 is secreted from cells like muscles to regulate basement membrane proteins. In the nematode brain, the basement membrane does not directly contact synapses. Instead, muscle-derived basement membrane coats one side of the glia, while glia contact synapses on their other side. MIG-17 modifies the muscle-derived basement membrane to modulate epidermal-glial crosstalk and sustain glia location and morphology during growth. Glia position in turn sustains the synaptic pattern established during embryogenesis. Our findings uncover a muscle-epidermis-glia signaling axis that sustains synaptic specificity during the organism's allometric growth.
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Affiliation(s)
- Jiale Fan
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Tingting Ji
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Kai Wang
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Jichang Huang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Mengqing Wang
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Laura Manning
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, New Haven, United States
| | - Xiaohua Dong
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Yanjun Shi
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Xumin Zhang
- State Key Laboratory of Genetic Engineering, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai, China
| | - Zhiyong Shao
- Department of Neurosurgery, the State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, the Institutes of Brain Science, and Zhongshan Hospital, Fudan University Shanghai, Shanghai, China
| | - Daniel A Colón-Ramos
- Program in Cellular Neuroscience, Neurodegeneration and Repair, Department of Neuroscience and Department of Cell Biology, Yale University School of Medicine, New Haven, United States.,Instituto de Neurobiología, Recinto de Ciencias Médicas, Universidad de Puerto Rico, San Juan, Puerto Rico
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Vincent A. ANTIBODIES AND RECEPTORS: From Neuromuscular Junction to Central Nervous System. Neuroscience 2020; 439:48-61. [PMID: 32194225 DOI: 10.1016/j.neuroscience.2020.03.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 12/12/2022]
Abstract
Myasthenia gravis (MG) is a relatively rare neurological disease that is usually associated with antibodies to the acetylcholine receptor (AChR). These antibodies (Abs) cause loss of the AChRs from the neuromuscular junction (NMJ), resulting in muscle weakness that can be life-threatening. Another form of the disease is caused by antibodies to muscle specific kinase (MuSK) that result in impaired AChR clustering and numbers at the NMJ, and may also interfere with presynaptic adaptive mechanisms. Other autoimmune disorders, Lambert Eaton myasthenic syndrome and acquired neuromyotonia, are associated with antibodies to presynaptic voltage-gated calcium and potassium channels respectively. All four conditions can be diagnosed by specific clinical features, electromyography and serum antibody tests, and can be treated effectively by a combination of pharmacological approaches and procedures that reduce the levels of the IgG antibodies. They form the first of a spectrum of diseases in which serum autoantibodies bind to extracellular domains of neuronal proteins throughout the nervous system and lead to constellations of clinical features including paralysis, sensory disturbance and pain, memory loss, seizures, psychiatric disturbance and movement disorders. This review will briefly summarize the ways in which this field has developed, since the 1970s when considerable contributions were made in Ricardo Miledi's laboratory at UCL.
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Affiliation(s)
- Angela Vincent
- Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, OX3 9DU, UK.
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