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De Rose DU, Ronci S, Caoci S, Maddaloni C, Diodato D, Catteruccia M, Fattori F, Bosco L, Pro S, Savarese I, Bersani I, Randi F, Trozzi M, Meucci D, Calzolari F, Salvatori G, Solinas A, Dotta A, Campi F. Vocal Cord Paralysis and Feeding Difficulties as Early Diagnostic Clues of Congenital Myasthenic Syndrome with Neonatal Onset: A Case Report and Review of Literature. J Pers Med 2023; 13:jpm13050798. [PMID: 37240968 DOI: 10.3390/jpm13050798] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 04/21/2023] [Accepted: 05/04/2023] [Indexed: 05/28/2023] Open
Abstract
Herein, we present a newborn female with congenital vocal cord paralysis who required a tracheostomy in the neonatal period. She also presented with feeding difficulties. She was later diagnosed with a clinical picture of congenital myasthenia, associated with three variants of the MUSK gene: the 27-month follow-up was described. In particular, the c.565C>T variant is novel and has never been described in the literature; it causes the insertion of a premature stop codon (p.Arg189Ter) likely leading to a consequent formation of a truncated nonfunctioning protein. We also systematically collected and summarized information on patients' characteristics of previous cases of congenital myasthenia with neonatal onset reported in the literature to date, and we compared them to our case. The literature reported 155 neonatal cases before our case, from 1980 to March 2022. Of 156 neonates with CMS, nine (5.8%) had vocal cord paralysis, whereas 111 (71.2%) had feeding difficulties. Ocular features were evident in 99 infants (63.5%), whereas facial-bulbar symptoms were found in 115 infants (73.7%). In one hundred sixteen infants (74.4%), limbs were involved. Respiratory problems were displayed by 97 infants (62.2%). The combination of congenital stridor, particularly in the presence of an apparently idiopathic bilateral vocal cord paralysis, and poor coordination between sucking and swallowing may indicate an underlying congenital myasthenic syndrome (CMS). Therefore, we suggest testing infants with vocal cord paralysis and feeding difficulties for MUSK and related genes to avoid a late diagnosis of CMS and improve outcomes.
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Affiliation(s)
| | - Sara Ronci
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Stefano Caoci
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Chiara Maddaloni
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Daria Diodato
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Michela Catteruccia
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Fabiana Fattori
- Laboratory of Medical Genetics, Translational Cytogenomics Research Unit, Bambino Gesù Children Hospital, IRCCS, 00165 Rome, Italy
| | - Luca Bosco
- Neuromuscular and Neurodegenerative Disorders Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
- Department of Science, University Roma Tre, 00146 Rome, Italy
| | - Stefano Pro
- Developmental Neurology Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Immacolata Savarese
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Iliana Bersani
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Franco Randi
- Neurosurgery Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Marilena Trozzi
- Airway Surgery Unit, Pediatric Surgery Department, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Duino Meucci
- Airway Surgery Unit, Pediatric Surgery Department, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Flaminia Calzolari
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Guglielmo Salvatori
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Agostina Solinas
- Neonatal Intensive Care Unit, Sant'Anna Hospital of Ferrara, 44124 Ferrara, Italy
| | - Andrea Dotta
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
| | - Francesca Campi
- Neonatal Intensive Care Unit, Bambino Gesù Children's Hospital, IRCCS, 00165 Rome, Italy
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miR-1933-3p is upregulated in skeletal muscles of MuSK+ EAMG mice and affects Impa1 and Mrpl27. Neurosci Res 2019; 151:46-52. [PMID: 30763589 DOI: 10.1016/j.neures.2019.02.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 02/03/2019] [Accepted: 02/06/2019] [Indexed: 12/15/2022]
Abstract
MuSK antibody seropositive (MuSK+) Myasthenia Gravis (MG) typically affects skeletal muscles of the bulbar area, including the omohyoid muscle, causing focal fatigue, weakness and atrophy. The profile of circulating extracellular microRNA (miRNA) is changed in MuSK + MG, but the intracellular miRNA profile in skeletal muscles of MuSK + MG and MuSK + experimental autoimmune MG (EAMG) remains unknown. This study elucidated the intracellular miRNA profile in the omohyoid muscle of mice with MuSK + EAMG. The levels of eleven mouse miRNAs were elevated and two mouse miRNAs were reduced in muscles of MuSK + EAMG mice. Transient expression of miR-1933-3p and miR-1930-5p in mouse muscle (C2C12) cells revealed several downregulated genes, out of which five had predicted binding sites for miR-1933-3p. The mRNA expression of mitochondrial ribosomal protein L27 (Mrpl27) and Inositol monophosphatase I (Impa1) was reduced in miR-1933-3p transfected C2C12 cells compared to control cells (p = 0.032 versus p = 0.020). Further, transient expression of miR-1933-3p reduced Impa1 protein accumulation in C2C12 cells. These findings provide novel insights of dysregulated miRNAs and their intracellular pathways in muscle tissue afflicted with MuSK + EAMG, providing a possible link to mitochondrial dysfunction and muscle atrophy observed in MuSK + MG.
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Yan M, Xing GL, Xiong WC, Mei L. Agrin and LRP4 antibodies as new biomarkers of myasthenia gravis. Ann N Y Acad Sci 2018; 1413:126-135. [PMID: 29377176 DOI: 10.1111/nyas.13573] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/08/2017] [Accepted: 11/11/2017] [Indexed: 12/13/2022]
Abstract
Myasthenia gravis (MG) is a common disorder that affects the neuromuscular junction. It is caused by antibodies against acetylcholine receptor and muscle-specific tyrosine kinase; however, some MG patients do not have antibodies against either of the proteins. Recent studies have revealed antibodies against agrin and its receptor LRP4-both critical for neuromuscular junction formation and maintenance-in MG patients from various populations. Results from experimental autoimmune MG animal models indicate that anti-LRP4 antibodies are causal to MG. Clinical studies have begun to reveal the significance of the new biomarkers. With their identification, MG appears to be a complex disease entity that can be classified into different subtypes with different etiology, each with unique symptoms. Future systematic studies of large cohorts of well-diagnosed MG patients are needed to determine whether each subtype of patients would respond to different therapeutic strategies. Results should contribute to the goal of precision medicine for MG patients. Anti-agrin and anti-LRP4 antibodies are also detectable in some patients with amyotrophic lateral sclerosis or Lou Gehrig's disease; however, whether they are a cause or response to the disorder remains unclear.
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Affiliation(s)
- Min Yan
- Institute of Life Science, Nanchang University, Nanchang, China.,School of Basic Medical Sciences, Nanchang University, Nanchang, China.,Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Guang-Lin Xing
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Wen-Cheng Xiong
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Louis Stokes Cleveland VAMC, Cleveland, Ohio
| | - Lin Mei
- Department of Neuroscience, School of Medicine, Case Western Reserve University, Cleveland, Ohio.,Louis Stokes Cleveland VAMC, Cleveland, Ohio
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Croxford JL, Miyake S. Animal Models for the Study of Neuroimmunological Disease. NEUROIMMUNOLOGICAL DISEASES 2016. [PMCID: PMC7122656 DOI: 10.1007/978-4-431-55594-0_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/29/2022]
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Abstract
The neuromuscular junction (NMJ) is a synapse between motor neurons and skeletal muscle fibers, and is critical for control of muscle contraction. Its formation requires neuronal agrin that acts by binding to LRP4 to stimulate MuSK. Mutations have been identified in agrin, MuSK, and LRP4 in patients with congenital myasthenic syndrome, and patients with myasthenia gravis develop antibodies against agrin, LRP4, and MuSK. However, it remains unclear whether the agrin signaling pathway is critical for NMJ maintenance because null mutation of any of the three genes is perinatal lethal. In this study, we generated imKO mice, a mutant strain whose LRP4 gene can be deleted in muscles by doxycycline (Dox) treatment. Ablation of the LRP4 gene in adult muscle enabled studies of its role in NMJ maintenance. We demonstrate that Dox treatment of P30 mice reduced muscle strength and compound muscle action potentials. AChR clusters became fragmented with diminished junctional folds and synaptic vesicles. The amplitude and frequency of miniature endplate potentials were reduced, indicating impaired neuromuscular transmission and providing cellular mechanisms of adult LRP4 deficiency. We showed that LRP4 ablation led to the loss of synaptic agrin and the 90 kDa fragments, which occurred ahead of other prejunctional and postjunctional components, suggesting that LRP4 may regulate the stability of synaptic agrin. These observations demonstrate that LRP4 is essential for maintaining the structural and functional integrity of the NMJ and that loss of muscle LRP4 in adulthood alone is sufficient to cause myasthenic symptoms.
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Evoli A, Iorio R. Characteristics of myasthenia gravis with antibodies to muscle-specific kinase and low-density lipoprotein-related receptor protein 4. ACTA ACUST UNITED AC 2015. [DOI: 10.1111/cen3.12173] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Amelia Evoli
- Institute of Neurology; Catholic University; Roma Italy
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Zhang B, Shen C, Bealmear B, Ragheb S, Xiong WC, Lewis RA, Lisak RP, Mei L. Autoantibodies to agrin in myasthenia gravis patients. PLoS One 2014; 9:e91816. [PMID: 24632822 PMCID: PMC3954737 DOI: 10.1371/journal.pone.0091816] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 02/02/2014] [Indexed: 11/19/2022] Open
Abstract
To determine if patients with myasthenia gravis (MG) have antibodies to agrin, a proteoglycan released by motor neurons and is critical for neuromuscular junction (NMJ) formation, we collected serum samples from 93 patients with MG with known status of antibodies to acetylcholine receptor (AChR), muscle specific kinase (MuSK) and lipoprotein-related 4 (LRP4) and samples from control subjects (healthy individuals and individuals with other diseases). Sera were assayed for antibodies to agrin. We found antibodies to agrin in 7 serum samples of MG patients. None of the 25 healthy controls and none of the 55 control neurological patients had agrin antibodies. Two of the four triple negative MG patients (i.e., no detectable AChR, MuSK or LRP4 antibodies, AChR-/MuSK-/LRP4-) had antibodies against agrin. In addition, agrin antibodies were detected in 5 out of 83 AChR+/MuSK-/LRP4- patients but were not found in the 6 patients with MuSK antibodies (AChR-/MuSK+/LRP4-). Sera from MG patients with agrin antibodies were able to recognize recombinant agrin in conditioned media and in transfected HEK293 cells. These sera also inhibited the agrin-induced MuSK phosphorylation and AChR clustering in muscle cells. Together, these observations indicate that agrin is another autoantigen in patients with MG and agrin autoantibodies may be pathogenic through inhibition of agrin/LRP4/MuSK signaling at the NMJ.
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Affiliation(s)
- Bin Zhang
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- Department of Physiology, Basic Medical School, Tongji Medical College, Huazhong University of Science & Technology, Wuhan, Hubei Province, P. R. China
| | - Chengyong Shen
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
| | - Beverly Bealmear
- Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, United States of America
| | - Samia Ragheb
- Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, United States of America
- Department of Biomedical Sciences, Oakland University William Beaumont School of Medicine, Rochester, Michigan, United States of America
| | - Wen-Cheng Xiong
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
| | - Richard A. Lewis
- Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, United States of America
- Department of Neurology, Cedars-Sinai Medical Center, West Hollywood, California, United States of America
| | - Robert P. Lisak
- Department of Neurology, School of Medicine, Wayne State University, Detroit, Michigan, United States of America
- Department of Immunology and Microbiology, School of Medicine, Wayne State University, Detroit, Michigan, United States of America
| | - Lin Mei
- Department of Neuroscience and Regenerative Medicine and Department of Neurology, Medical College of Georgia, Georgia Regents University, Augusta, Georgia, United States of America
- Charlie Norwood VA Medical Center, Augusta, Georgia, United States of America
- * E-mail:
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George S, Paulick S, Knütter I, Röber N, Hiemann R, Roggenbuck D, Conrad K, Küpper JH. Stable expression of human muscle-specific kinase in HEp-2 M4 cells for automatic immunofluorescence diagnostics of myasthenia gravis. PLoS One 2014; 9:e83924. [PMID: 24416182 PMCID: PMC3886972 DOI: 10.1371/journal.pone.0083924] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 11/11/2013] [Indexed: 12/22/2022] Open
Abstract
Muscle-specific kinase (MuSK) belongs to the nicotinic acetylcholine receptor complex which is targeted by pathogenic autoantibodies causing Myasthenia gravis. While up to 95% of patients with generalized Myasthenia gravis were shown to be positive for acetylcholine receptor-specific autoantibodies, up to 70% of the remaining patients develop autoantibodies against MuSK. Discrimination of the autoantibody specificity is important for therapy of Myasthenia gravis. Recently, the new automatic fluorescence assessment platform AKLIDES has been developed for immunofluorescence-based diagnostics of autoimmune diseases. In order to establish an AKLIDES procedure for the detection of MuSK-specific autoantibodies (anti-MuSK), we developed a recombinant HEp-2 cell clone expressing the human MuSK cDNA. Here we show at the mRNA and protein level that the cell clone HEp-2 M4 stably expresses human MuSK. We provide evidence for a localization of MuSK at the cell membrane. Using cell clone HEp-2 M4 on the AKLIDES system, we investigated 34 patient sera that were previously tested anti-MuSK positive by radioimmunoassay as positive controls. As negative controls, we tested 29 acetylcholine receptor-positive but MuSK-negative patient sera, 30 amytrophic lateral sclerosis (ALS) patient sera and 45 blood donors. HEp-2 M4 cells revealed a high specificity for the detection of MuSK autoantibodies from 25 patient sera assessed by a specific pattern on HEp-2 M4 cells. By using appropriate cell culture additives, the fraction of cells stained positive with anti-MuSK containing sera can be increased from 2-16% to 10-48%, depending on the serum. In conclusion, we provide data showing that the novel recombinant cell line HEp-2 M4 can be used to screen for anti-MuSK with the automatic AKLIDES system.
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Affiliation(s)
- Sandra George
- Faculty of Science, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
- Institute of Immunology, Technical University Dresden, Dresden, Germany
| | - Silvia Paulick
- Faculty of Science, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
| | - Ilka Knütter
- GA Generic Assays GmbH, Dahlewitz/Berlin, Germany
| | - Nadja Röber
- Institute of Immunology, Technical University Dresden, Dresden, Germany
| | - Rico Hiemann
- GA Generic Assays GmbH, Dahlewitz/Berlin, Germany
| | - Dirk Roggenbuck
- Faculty of Science, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
- GA Generic Assays GmbH, Dahlewitz/Berlin, Germany
| | - Karsten Conrad
- Institute of Immunology, Technical University Dresden, Dresden, Germany
| | - Jan-Heiner Küpper
- Faculty of Science, Brandenburg University of Technology Cottbus-Senftenberg, Senftenberg, Germany
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Shen C, Lu Y, Zhang B, Figueiredo D, Bean J, Jung J, Wu H, Barik A, Yin DM, Xiong WC, Mei L. Antibodies against low-density lipoprotein receptor-related protein 4 induce myasthenia gravis. J Clin Invest 2013; 123:5190-202. [PMID: 24200689 DOI: 10.1172/jci66039] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/29/2013] [Indexed: 11/17/2022] Open
Abstract
Myasthenia gravis (MG) is the most common disorder affecting the neuromuscular junction (NMJ). MG is frequently caused by autoantibodies against acetylcholine receptor (AChR) and a kinase critical for NMJ formation, MuSK; however, a proportion of MG patients are double-negative for anti-AChR and anti-MuSK antibodies. Recent studies in these subjects have identified autoantibodies against low-density lipoprotein receptor-related protein 4 (LRP4), an agrin receptor also critical for NMJ formation. LRP4 autoantibodies have not previously been implicated in MG pathogenesis. Here we demonstrate that mice immunized with the extracellular domain of LRP4 generated anti-LRP4 antibodies and exhibited MG-associated symptoms, including muscle weakness, reduced compound muscle action potentials (CMAPs), and compromised neuromuscular transmission. Additionally, fragmented and distorted NMJs were evident at both the light microscopic and electron microscopic levels. We found that anti-LRP4 sera decreased cell surface LRP4 levels, inhibited agrin-induced MuSK activation and AChR clustering, and activated complements, revealing potential pathophysiological mechanisms. To further confirm the pathogenicity of LRP4 antibodies, we transferred IgGs purified from LRP4-immunized rabbits into naive mice and found that they exhibited MG-like symptoms, including reduced CMAP and impaired neuromuscular transmission. Together, these data demonstrate that LRP4 autoantibodies induce MG and that LRP4 contributes to NMJ maintenance in adulthood.
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Mechanisms associated with the pathogenicity of antibodies against muscle-specific kinase in myasthenia gravis. Autoimmun Rev 2013; 12:912-7. [DOI: 10.1016/j.autrev.2013.03.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 12/27/2022]
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Koneczny I, Cossins J, Vincent A. The role of muscle-specific tyrosine kinase (MuSK) and mystery of MuSK myasthenia gravis. J Anat 2013; 224:29-35. [PMID: 23458718 DOI: 10.1111/joa.12034] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/05/2013] [Indexed: 11/28/2022] Open
Abstract
MuSK myasthenia gravis is a rare, severe autoimmune disease of the neuromuscular junction, only identified in 2001, with unclear pathogenic mechanisms. In this review we describe the clinical aspects that distinguish MuSK MG from AChR MG, review what is known about the role of MuSK in the development and function of the neuromuscular junction, and discuss the data that address how the antibodies to MuSK lead to neuromuscular transmission failure.
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Affiliation(s)
- Inga Koneczny
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
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Poulas K, Koutsouraki E, Kordas G, Kokla A, Tzartos SJ. Anti-MuSK- and anti-AChR-positive myasthenia gravis induced by d-penicillamine. J Neuroimmunol 2012; 250:94-8. [DOI: 10.1016/j.jneuroim.2012.05.011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 03/17/2012] [Accepted: 05/16/2012] [Indexed: 10/28/2022]
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Barik A, Xiong WC, Mei L. MuSK: A Kinase Critical for the Formation and Maintenance of the Neuromuscular Junction. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/978-1-61779-824-5_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
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Mori S, Yamada S, Kubo S, Chen J, Matsuda S, Shudou M, Maruyama N, Shigemoto K. Divalent and monovalent autoantibodies cause dysfunction of MuSK by distinct mechanisms in a rabbit model of myasthenia gravis. J Neuroimmunol 2012; 244:1-7. [DOI: 10.1016/j.jneuroim.2011.12.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2011] [Revised: 11/07/2011] [Accepted: 12/05/2011] [Indexed: 12/21/2022]
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Grover KM, Sripathi N, Elias SB. Muscle-specific kinase-antibody-positive myasthenia gravis after autologous bone marrow transplantation. J Clin Neuromuscul Dis 2012; 13:146-148. [PMID: 22538309 DOI: 10.1097/cnd.0b013e31821c560e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
A 44-year-old man presented with oculobulbar weakness approximately 5 years after autologous bone marrow transplantation (BMT). His workup led to the diagnosis of muscle-specific kinase-antibody-related myasthenia gravis (MG). There has been only one case report of muscle-specific kinase-antibody-positive MG after BMT, which was allogeneic. We report the first case of autologous BMT-associated MG with muscle-specific kinase antibody. The pathogenic mechanisms of immune dysregulation leading to MG after BMT are discussed.
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Mori S, Kubo S, Akiyoshi T, Yamada S, Miyazaki T, Hotta H, Desaki J, Kishi M, Konishi T, Nishino Y, Miyazawa A, Maruyama N, Shigemoto K. Antibodies against muscle-specific kinase impair both presynaptic and postsynaptic functions in a murine model of myasthenia gravis. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:798-810. [PMID: 22142810 DOI: 10.1016/j.ajpath.2011.10.031] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/15/2011] [Revised: 10/04/2011] [Accepted: 10/25/2011] [Indexed: 01/17/2023]
Abstract
Antibodies against acetylcholine receptors (AChRs) cause pathogenicity in myasthenia gravis (MG) patients through complement pathway-mediated destruction of postsynaptic membranes at neuromuscular junctions (NMJs). However, antibodies against muscle-specific kinase (MuSK), which constitute a major subclass of antibodies found in MG patients, do not activate the complement pathway. To investigate the pathophysiology of MuSK-MG and establish an experimental autoimmune MG (EAMG) model, we injected MuSK protein into mice deficient in complement component five (C5). MuSK-injected mice simultaneously developed severe muscle weakness, accompanied by an electromyographic pattern such as is typically observed in MG patients. In addition, we observed morphological and functional defects in the NMJs of EAMG mice, demonstrating that complement activation is not necessary for the onset of MuSK-MG. Furthermore, MuSK-injected mice exhibited acetylcholinesterase (AChE) inhibitor-evoked cholinergic hypersensitivity, as is observed in MuSK-MG patients, and a decrease in both AChE and the AChE-anchoring protein collagen Q at postsynaptic membranes. These findings suggest that MuSK is indispensable for the maintenance of NMJ structure and function, and that disruption of MuSK activity by autoantibodies causes MG. This mouse model of EAMG could be used to develop appropriate medications for the treatment of MuSK-MG in humans.
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Affiliation(s)
- Shuuichi Mori
- Department of Geriatric Medicine, Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan
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Punga AR, Lin S, Oliveri F, Meinen S, Rüegg MA. Muscle-selective synaptic disassembly and reorganization in MuSK antibody positive MG mice. Exp Neurol 2011; 230:207-17. [DOI: 10.1016/j.expneurol.2011.04.018] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Revised: 04/15/2011] [Accepted: 04/21/2011] [Indexed: 11/25/2022]
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Vrolix K, Fraussen J, Molenaar PC, Losen M, Somers V, Stinissen P, De Baets MH, Martínez-Martínez P. The auto-antigen repertoire in myasthenia gravis. Autoimmunity 2010; 43:380-400. [PMID: 20380581 DOI: 10.3109/08916930903518073] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myasthenia Gravis (MG) is an antibody-mediated autoimmune disorder affecting the postsynaptic membrane of the neuromuscular junction (NMJ). MG is characterized by an impaired signal transmission between the motor neuron and the skeletal muscle cell, caused by auto-antibodies directed against NMJ proteins. The auto-antibodies target the nicotinic acetylcholine receptor (nAChR) in about 90% of MG patients. In approximately 5% of MG patients, the muscle specific kinase (MuSK) is the auto-antigen. In the remaining 5% of MG patients, however, antibodies against the nAChR or MuSK are not detectable (idiopathic MG, iMG). Although only the anti-nAChR and anti-MuSK auto-antibodies have been demonstrated to be pathogenic, several other antibodies recognizing self-antigens can also be found in MG patients. Various auto-antibodies associated with thymic abnormalities have been reported, as well as many non-MG-specific auto-antibodies. However, their contribution to the cause, pathology and severity of the disease is still poorly understood. Here, we comprehensively review the reported auto-antibodies in MG patients and discuss their role in the pathology of this autoimmune disease.
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Affiliation(s)
- Kathleen Vrolix
- Division of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, The Netherlands
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Shigemoto K, Kubo S, Mori S, Yamada S, Akiyoshi T, Miyazaki T. Muscle weakness and neuromuscular junctions in aging and disease. Geriatr Gerontol Int 2010; 10 Suppl 1:S137-47. [DOI: 10.1111/j.1447-0594.2010.00608.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Aubert S, Salort-Campana E, Franques J, Uzenot D, Pouget J. Myasthénie séronégative et myasthénie avec anticorps anti-MuSK : une série rétrospective de 20 cas. Rev Neurol (Paris) 2009; 165:901-10. [DOI: 10.1016/j.neurol.2009.01.049] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2008] [Revised: 11/28/2008] [Accepted: 01/15/2009] [Indexed: 11/30/2022]
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Yanagawa Y, Hongo Y, Shiozaki H, Kamakura K, Sonoo M, Motomura M. Muscle-specific tyrosine kinase-antibody-positive myasthenic crisis with detailed electrophysiologic studies. Am J Emerg Med 2009; 27:754.e5-6. [PMID: 19751644 DOI: 10.1016/j.ajem.2008.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Accepted: 10/06/2008] [Indexed: 10/20/2022] Open
Affiliation(s)
- Youichi Yanagawa
- Department of Traumatology and Critical Care Medicine, National Defense Medical College (NDMC), Tokorozawa, Saitama 359-8513, Japan.
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Helgeland G, Luckman SP, Romi FR, Jonassen AK, Gilhus NE. Myasthenia gravis sera have no effect on cardiomyocytes in vitro. J Neuroimmunol 2008; 201-202:74-9. [PMID: 18632164 DOI: 10.1016/j.jneuroim.2008.05.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2008] [Revised: 05/27/2008] [Accepted: 05/28/2008] [Indexed: 10/21/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder primarily caused by circulating autoantibodies targeting the nicotinic acetylcholine receptor. Several studies have suggested a link between MG and heart disease. Girardi heart cells were treated with MG sera, measuring cytotoxic effects using flow cytometry, adenylate kinase (AK) release and evaluating morphology. MG sera did not induce morphological changes in the cells. AK release from cells treated with MG sera did not exceed controls and flow cytometric examination did not reveal any increase in dead or apoptotic cells. We conclude that MG sera have no cytotoxic effect in our heart cell culture system.
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Affiliation(s)
- Geir Helgeland
- Department of Clinical Medicine, Section for Neurology, University of Bergen, Norway.
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Vincent A, Leite MI, Farrugia ME, Jacob S, Viegas S, Shiraishi H, Benveniste O, Morgan BP, Hilton-Jones D, Newsom-Davis J, Beeson D, Willcox N. Myasthenia gravis seronegative for acetylcholine receptor antibodies. Ann N Y Acad Sci 2008; 1132:84-92. [PMID: 18567857 DOI: 10.1196/annals.1405.020] [Citation(s) in RCA: 81] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Antibodies to muscle-specific kinase (MuSK) are found in a variable proportion of patients with myasthenia without typical acetylcholine receptor (AChR) antibodies, but their characteristics and pathogenic mechanisms are not fully understood. We discuss the incidence and pathogenicity of MuSK antibodies and how clinical studies, animal models, and cultured cell lines can be used to elucidate their pathogenic mechanisms. Patients without either AChR or MuSK antibodies (seronegative myasthenia) appear to present another disease subtype that is highly similar to that of typical myasthenia gravis. We demonstrate a new method that detects AChR antibodies in these patients and show that these low-affinity AChR antibodies are predominantly IgG1 and can activate complement C3b deposition. Similarly MuSK antibodies, although mainly IgG4, are partially IgG1 and can activate C3b deposition. Overall, these results suggest that complement-activation may be an important pathogenic mechanism even in patients without conventional AChR antibodies.
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Affiliation(s)
- Angela Vincent
- Neurosciences Group, Weatherall Institute of Molecular Medicine and Department of Clinical Neurology, John Radcliffe Hospital, Oxford, United Kingdom.
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