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Zong S, Vinke AM, Du P, Hoffmann C, Mané-Damas M, Molenaar PC, Damoiseaux JGMC, Losen M, Rouhl RPW, Martinez-Martinez P. Anti-GAD65 autoantibody levels measured by ELISA and alternative types of immunoassays in relation to neuropsychiatric diseases versus diabetes mellitus type 1. Front Neurol 2023; 14:1111063. [PMID: 37305746 PMCID: PMC10248002 DOI: 10.3389/fneur.2023.1111063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Accepted: 05/10/2023] [Indexed: 06/13/2023] Open
Abstract
Background Anti-GAD65 autoantibodies (GAD65-Abs) may occur in patients with epilepsy and other neurological disorders, but the clinical significance is not clear-cut. Whereas high levels of GAD65-Abs are considered pathogenic in neuropsychiatric disorders, low or moderate levels are only considered as mere bystanders in, e.g., diabetes mellitus type 1 (DM1). The value of cell-based assays (CBA) and immunohistochemistry (IHC) for GAD65-Abs detection has not been clearly evaluated in this context. Objective To re-evaluate the assumption that high levels of GAD65-Abs are related to neuropsychiatric disorders and lower levels only to DM1 and to compare ELISA results with CBA and IHC to determine the additional value of these tests. Methods 111 sera previously assessed for GAD65-Abs by ELISA in routine clinical practice were studied. Clinical indications for testing were, e.g., suspected autoimmune encephalitis or epilepsy (neuropsychiatric cohort; n = 71, 7 cases were initially tested positive for GAD65-Abs by ELISA), and DM1 or latent autoimmune diabetes in adults (DM1/LADA cohort (n = 40, all were initially tested positive)). Sera were re-tested for GAD65-Abs by ELISA, CBA, and IHC. Also, we examined the possible presence of GAD67-Abs by CBA and of other neuronal autoantibodies by IHC. Samples that showed IHC patterns different from GAD65 were further tested by selected CBAs. Results ELISA retested GAD65-Abs level in patients with neuropsychiatric diseases was higher than in patients with DM1/LADA (only retested positive samples were compared; 6 vs. 38; median 47,092 U/mL vs. 581 U/mL; p = 0.02). GAD-Abs showed positive both by CBA and IHC only if antibody levels were above 10,000 U/mL, without a difference in prevalence between the studied cohorts. We found other neuronal antibodies in one patient with epilepsy (mGluR1-Abs, GAD-Abs negative), and in a patient with encephalitis, and two patients with LADA. Conclusion GAD65-Abs levels are significantly higher in patients with neuropsychiatric disease than in patients with DM1/LADA, however, positivity in CBA and IHC only correlates with high levels of GAD65-Abs, and not with the underlying diseases.
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Affiliation(s)
- Shenghua Zong
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Anita M. Vinke
- Department of Neurology, Maastricht University Medical Center (MUMC +), Maastricht, Netherlands
| | - Peng Du
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Carolin Hoffmann
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
- Algarve Biomedical Center, Algarve Biomedical Center Research Institute, Faro, Portugal
| | - Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Peter C. Molenaar
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | | | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
| | - Rob P. W. Rouhl
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
- Department of Neurology, Maastricht University Medical Center (MUMC +), Maastricht, Netherlands
- Academic Centre for Epileptology Kempenhaeghe/MUMC+, Maastricht, Netherlands
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience (MHeNS), Maastricht University, Maastricht, Netherlands
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Hoffmann C, Zong S, Mané-Damas M, Stevens J, Malyavantham K, Küçükali Cİ, Tüzün E, De Hert M, van Beveren NJM, González-Vioque E, Arango C, Damoiseaux JGMC, Rutten BP, Molenaar PC, Losen M, Martinez-Martinez P. The search for an autoimmune origin of psychotic disorders: Prevalence of autoantibodies against hippocampus antigens, glutamic acid decarboxylase and nuclear antigens. Schizophr Res 2021; 228:462-471. [PMID: 33581586 DOI: 10.1016/j.schres.2020.12.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 12/12/2020] [Accepted: 12/30/2020] [Indexed: 12/31/2022]
Abstract
The etiology of psychotic disorders is still unknown, but in a subgroup of patients symptoms might be caused by an autoimmune reaction. In this study, we tested patterns of autoimmune reactivity against potentially novel hippocampal antigens. Serum of a cohort of 621 individuals with psychotic disorders and 257 controls were first tested for reactivity on neuropil of rat brain sections. Brain reactive sera (67 diseased, 27 healthy) were further tested for antibody binding to glutamic acid decarboxylase (GAD) isotype 65 and 67 by cell-based assay (CBA). A sub-cohort of 199 individuals with psychotic disorders and 152 controls was tested for the prevalence of anti-nuclear antibodies (ANA) on HEp2-substrate as well as for reactivity to double-stranded DNA, ribosomal P (RPP), and cardiolipin (CL). Incubation of rat brain with serum resulted in unidentified hippocampal binding patterns in both diseased and control groups. Upon screening with GAD CBA, one of these patterns was identified as GAD65 in one individual with schizophrenia and also in one healthy individual. Two diseased and two healthy individuals had low antibody levels targeting GAD67 by CBA. Antibody reactivity on HEp-2-substrate was increased in patients with schizoaffective disorder, but only in 3 patients did antibody testing hint at a possible diagnosis of systemic lupus erythematosus. Although reactivity of serum to intracellular antigens might be increased in patients with psychotic disorder, no specific targets could be identified. GAD antibodies are very rare and do not seem increased in serum of patients with psychotic disorders.
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Affiliation(s)
- Carolin Hoffmann
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Shenghua Zong
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Jo Stevens
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | | | - Cem İsmail Küçükali
- Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, Istanbul, Turkey
| | - Erdem Tüzün
- Department of Neuroscience, Institute for Experimental Medical Research (DETAE), Istanbul University, Istanbul, Turkey
| | - Marc De Hert
- UPC KU Leuven, KU Leuven Department of Neurosciences, Belgium; Antwerp Health Law and Ethics Chair - AHLEC, University Antwerp, Antwerp, Belgium
| | - Nico J M van Beveren
- Department of Psychiatry, Erasmus University Medical Center, Rotterdam, the Netherlands
| | - Emiliano González-Vioque
- Child and Adolescent Psychiatry Department, Hospital General Universitario, Gregorio Marañón, School of Medicine, Universidad Complutense, IiSGM, CIBERSAM, Madrid, Spain
| | - Celso Arango
- Child and Adolescent Psychiatry Department, Hospital General Universitario, Gregorio Marañón, School of Medicine, Universidad Complutense, IiSGM, CIBERSAM, Madrid, Spain
| | - Jan G M C Damoiseaux
- Central Diagnostic Laboratory, Maastricht University Medical Center, Maastricht, the Netherlands
| | - Bart P Rutten
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
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3
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Mané-Damas M, Vinke A, Hoffmann C, Zong S, Losen M, Molenaar PC, Damoiseaux J, Koudijs S, Rouhl RPW, Martinez-Martinez P. Unidentified Neuronal Surface IgG Autoantibodies in a Case of Hashimoto's Encephalopathy. Front Immunol 2020; 11:1358. [PMID: 32733453 PMCID: PMC7358532 DOI: 10.3389/fimmu.2020.01358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 05/28/2020] [Indexed: 12/03/2022] Open
Abstract
Hashimoto's encephalopathy is an encephalitis of presumed autoimmune origin characterized by the presence of autoantibodies against thyroid proteins. We present a case of a young patient with pre-existing Hashimoto's thyroiditis and progressive cognitive complaints, absence-like episodes, and sporadic bilateral epileptiform frontal and frontotemporal activity. No abnormalities were observed during the neurological examination and on MRI. Antibodies to thyroid peroxidase (TPO) were elevated and remained positive while the symptoms were present. Levothyroxine and methylprednisolone did not ameliorate the complaints. Subsequent treatment with high-dose intravenous immunoglobulins (IVIG) led to improved cognitive functions and to the disappearance of the absence-like-episodes. Patient's serum, but not CSF, gave a characteristic IgG-specific hippocampal pattern in rat brain immunohistochemistry; this immunoreactivity was maintained after specific and complete depletion of TPO antibodies. Serum IgG bound to primary neurons in cell culture, likely targeting a yet unidentified neuronal surface antigen. The clinical response to IVIG suggests but does not prove, that the circulating novel autoantibodies may induce the encephalopathy. It would be of interest to investigate more patients with Hashimoto's encephalopathy for the presence of neuronal surface autoantibodies, to define their role in the disease and their target antigen(s).
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Affiliation(s)
- Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Anita Vinke
- Department of Neurology, Maastricht UMC+, Maastricht, Netherlands
| | - Carolin Hoffmann
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Shenghua Zong
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
| | - Jan Damoiseaux
- Central Diagnostic Laboratory, Maastricht UMC+, Maastricht, Netherlands
| | - Suzanne Koudijs
- Department of Neurology, Maastricht UMC+, Maastricht, Netherlands
| | - Rob P W Rouhl
- School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands.,Department of Neurology, Maastricht UMC+, Maastricht, Netherlands.,Academic Center for Epileptology Kempenhaeghe/MUMC+, Heeze and Maastricht, Netherlands
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, Maastricht University, Maastricht, Netherlands.,School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Maastricht, Netherlands
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Hoffmann C, Zong S, Mané-Damas M, Molenaar PC, Losen M, Titulaer MJ, Martinez-Martinez P. Absence of Autoantibodies Against Neuronal Surface Antigens in Sera of Patients With Psychotic Disorders. JAMA Psychiatry 2020; 77:322-325. [PMID: 31746971 PMCID: PMC6902152 DOI: 10.1001/jamapsychiatry.2019.3679] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
This study examines the prevalence of autoantibodies against neuronal surface antigens in the sera of individuals with psychotic disorders compared with control participants.
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Affiliation(s)
- Carolin Hoffmann
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Shenghua Zong
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Marina Mané-Damas
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Peter C. Molenaar
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Mario Losen
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | | | - Pilar Martinez-Martinez
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
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5
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Mané-Damas M, Hoffmann C, Zong S, Tan A, Molenaar PC, Losen M, Martinez-Martinez P. Autoimmunity in psychotic disorders. Where we stand, challenges and opportunities. Autoimmun Rev 2019; 18:102348. [PMID: 31323365 DOI: 10.1016/j.autrev.2019.102348] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 02/26/2019] [Indexed: 12/24/2022]
Abstract
Psychotic disorders are debilitating mental illnesses associated with abnormalities in various neurotransmitter systems. The development of disease-modifing therapies has been hampered by the mostly unknown etiologies and pathophysiologies. Autoantibodies against several neuronal antigens are responsible for autoimmune encephalitis. These autoantibodies disrupt neurotransmission within the brain, resulting in a wide range of psychiatric and neurologic manifestations, including psychosis. The overlap of symptoms of autoimmune encephalitis with psychotic disorders raised the question as to whether autoantibodies against a number of receptors, ion channel and associated proteins could ultimately be responsible for some forms of psychosis. Here we review our current knowledge, on antibody mediated autoimmunity in psychotic disorders, the different diagnostic methods and their limitations, as well as on varying therapeutic approaches targeting the immune system.
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Affiliation(s)
- Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Carolin Hoffmann
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Shenghua Zong
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Amanda Tan
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School of Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.
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6
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Koneczny I, Rennspiess D, Marcuse F, Dankerlui N, Abdul Hamid M, Mané-Damas M, Maessen J, Van Schil P, Saxena A, Zisimopoulou P, Lazaridis K, Woodhall M, Karagiorgou K, Tzartos J, Tzartos S, De Baets MH, Molenaar PC, Marx A, Zur Hausen A, Losen M, Martinez-Martinez P. Characterization of the thymus in Lrp4 myasthenia gravis: Four cases. Autoimmun Rev 2018; 18:50-55. [PMID: 30414949 DOI: 10.1016/j.autrev.2018.07.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Accepted: 07/24/2018] [Indexed: 12/20/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease of the neuromuscular junction. Most patients have pathogenic autoantibodies against the acetylcholine receptor (AChR). In the last years a novel subpopulation of MG patients has been described that harbors antibodies against low-density lipoprotein receptor-related protein 4 (Lrp4), another postsynaptic neuromuscular antigen. In early-onset AChR MG (EOMG), the thymus plays an important role in immunopathogenesis, and early thymectomy is beneficial. It is still unknown if the thymus plays any role in Lrp4-MG. In this pilot study, we compared thymus samples from four patients with Lrp4-MG (one pre-treated with immunosuppressive drugs), four non-MG controls and five EOMG patients (not pretreated with immunosuppressive drugs). Immunohistochemistry of the Lrp4-MG thymi revealed normal architecture, with normal numbers and distribution of B-cells, lymphoid follicles and Hassall's corpuscles. Primary CD23+ lymphoid follicles were similarly infrequent in Lrp4-MG and control thymic sections. In none of the control or Lrp4-MG thymi did we find secondary follicles with CD10+ germinal centers. These were evident in 2 of the 5 EOMG thymi, where primary lymphoid follicles were also more frequent on average, thus showing considerable heterogeneity between patients. Even if characteristic pathological thymic changes were not observed in the Lrp4 subgroup, we cannot exclude a role for the thymus in Lrp4-MG pathogenesis, since one Lrp4-MG patient went into clinical remission after thymectomy alone (at one year follow-up) and one more improved after thymectomy in combination with immunosuppressive therapy.
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Affiliation(s)
- Inga Koneczny
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Dorit Rennspiess
- Department of Pathology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Florit Marcuse
- Department of Pathology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Nathalie Dankerlui
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Myurgia Abdul Hamid
- Department of Pathology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Marina Mané-Damas
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Jos Maessen
- Department of Pathology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands
| | - Paul Van Schil
- Dept. of Thoracic and Vascular Surgery, University Hospital of Antwerp, Wilrijkstraat 10, Edegem (Antwerp), B- 2650, Belgium
| | - Abhishek Saxena
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Paraskevi Zisimopoulou
- Department of Neurobiology, Hellenic Pasteur Institute, 127 Vas. Sofias Avenue, 11521 Athens, Greece
| | - Konstantinos Lazaridis
- Department of Neurobiology, Hellenic Pasteur Institute, 127 Vas. Sofias Avenue, 11521 Athens, Greece
| | - Mark Woodhall
- Neurosciences Group, Nuffield Department of Clinical Neurosciences, Level 6, West Wing, University of Oxford, Oxford OX3 9DU, UK
| | | | - John Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, 127 Vas. Sofias Avenue, 11521 Athens, Greece; Tzartos Neuro Diagnostics, 3 Eslin Street, 11523 Athens, Greece
| | - Socrates Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, 127 Vas. Sofias Avenue, 11521 Athens, Greece
| | - Marc H De Baets
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands
| | - Alexander Marx
- Institute of Pathology, University Medical Centre Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, D-68167 Mannheim, Germany
| | - Axel Zur Hausen
- Department of Pathology, Maastricht University Medical Centre, 6229 HX Maastricht, the Netherlands; GROW: School for Oncology and Developmental Biology, Maastricht University Medical Centre, 6200 MD Maastricht, the Netherlands
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands.
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, the Netherlands.
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Koneczny I, Stevens JAA, De Rosa A, Huda S, Huijbers MG, Saxena A, Maestri M, Lazaridis K, Zisimopoulou P, Tzartos S, Verschuuren J, van der Maarel SM, van Damme P, De Baets MH, Molenaar PC, Vincent A, Ricciardi R, Martinez-Martinez P, Losen M. IgG4 autoantibodies against muscle-specific kinase undergo Fab-arm exchange in myasthenia gravis patients. J Autoimmun 2016; 77:104-115. [PMID: 27965060 DOI: 10.1016/j.jaut.2016.11.005] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 10/17/2016] [Accepted: 11/22/2016] [Indexed: 01/13/2023]
Abstract
Autoimmunity mediated by IgG4 subclass autoantibodies is an expanding field of research. Due to their structural characteristics a key feature of IgG4 antibodies is the ability to exchange Fab-arms with other, unrelated, IgG4 molecules, making the IgG4 molecule potentially monovalent for the specific antigen. However, whether those disease-associated antigen-specific IgG4 are mono- or divalent for their antigens is unknown. Myasthenia gravis (MG) with antibodies to muscle specific kinase (MuSK-MG) is a well-recognized disease in which the predominant pathogenic IgG4 antibody binds to extracellular epitopes on MuSK at the neuromuscular junction; this inhibits a pathway that clusters the acetylcholine (neurotransmitter) receptors and leads to failure of neuromuscular transmission. In vitro Fab-arm exchange-inducing conditions were applied to MuSK antibodies in sera, purified IgG4 and IgG1-3 sub-fractions. Solid-phase cross-linking assays were established to determine the extent of pre-existing and inducible Fab-arm exchange. Functional effects of the resulting populations of IgG4 antibodies were determined by measuring inhibition of agrin-induced AChR clustering in C2C12 cells. To confirm the results, κ/κ, λ/λ and hybrid κ/λ IgG4s were isolated and tested for MuSK antibodies. At least fifty percent of patients had IgG4, but not IgG1-3, MuSK antibodies that could undergo Fab-arm exchange in vitro under reducing conditions. Also MuSK antibodies were found in vivo that were divalent (monospecific for MuSK). Fab-arm exchange with normal human IgG4 did not prevent the inhibitory effect of serum derived MuSK antibodies on AChR clustering in C2C12 mouse myotubes. The results suggest that a considerable proportion of MuSK IgG4 could already be Fab-arm exchanged in vivo. This was confirmed by isolating endogenous IgG4 MuSK antibodies containing both κ and λ light chains, i.e. hybrid IgG4 molecules. These new findings demonstrate that Fab-arm exchanged antibodies are pathogenic.
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Affiliation(s)
- Inga Koneczny
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Jo A A Stevens
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Anna De Rosa
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy
| | - Saif Huda
- Neurology Department, Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Maartje G Huijbers
- Department of Neurology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands; Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Abhishek Saxena
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Michelangelo Maestri
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy
| | - Konstantinos Lazaridis
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue 115 21, Ampelokipi, Athens, Greece; Neurology Department, University Hospital, Herestraat 49, 3000 Leuven, Belgium
| | - Paraskevi Zisimopoulou
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue 115 21, Ampelokipi, Athens, Greece; Neurology Department, University Hospital, Herestraat 49, 3000 Leuven, Belgium
| | - Socrates Tzartos
- Hellenic Pasteur Institute, 127 Vasilissis Sofias Avenue 115 21, Ampelokipi, Athens, Greece; Neurology Department, University Hospital, Herestraat 49, 3000 Leuven, Belgium
| | - Jan Verschuuren
- Department of Neurology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Silvère M van der Maarel
- Department of Human Genetics, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - Philip van Damme
- Neurology Department, University Hospital, Herestraat 49, 3000 Leuven, Belgium; KU Leuven - University of Leuven, Department of Neurosciences, VIB - Vesalius Research Center, Experimental Neurology - Laboratory of Neurobiology, Leuven, Belgium
| | - Marc H De Baets
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Peter C Molenaar
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands
| | - Angela Vincent
- Neurology Department, Nuffield Department of Clinical Neurosciences, West Wing, John Radcliffe Hospital, Oxford OX3 9DU, United Kingdom
| | - Roberta Ricciardi
- Department of Clinical and Experimental Medicine, Neurology Unit, University of Pisa, Via Paradisa 2, 56124 Pisa, Italy
| | - Pilar Martinez-Martinez
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands.
| | - Mario Losen
- Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Universiteitssingel 50, 6229 ER Maastricht, The Netherlands.
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Hillary FG, Medaglia JD, Gates KM, Molenaar PC, Good DC. Examining network dynamics after traumatic brain injury using the extended unified SEM approach. Brain Imaging Behav 2015; 8:435-45. [PMID: 23138853 DOI: 10.1007/s11682-012-9205-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The current study uses effective connectivity modeling to examine how individuals with traumatic brain injury (TBI) learn a new task. We make use of recent advancements in connectivity modeling (extended unified structural equation modeling, euSEM) and a novel iterative grouping procedure (Group Iterative Multiple Model Estimation, GIMME) in order to examine network flexibility after injury. The study enrolled 12 individuals sustaining moderate and severe TBI to examine the influence of task practice on connections between 8 network nodes (bilateral prefrontal cortex, anterior cingulate, inferior parietal lobule, and Crus I in the cerebellum). The data demonstrate alterations in networks from pre to post practice and differences in the models based upon distinct learning trajectories observed within the TBI sample. For example, better learning in the TBI sample was associated with diminished connectivity within frontal systems and increased frontal to parietal connectivity. These findings reveal the potential for using connectivity modeling and the euSEM to examine dynamic networks during task engagement and may ultimately be informative regarding when networks are moving in and out of periods of neural efficiency.
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Affiliation(s)
- F G Hillary
- Department of Psychology, The Pennsylvania State University, 347 Moore Building, University Park, PA, 16802, USA,
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9
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Losen M, Martinez-Martinez P, Molenaar PC, Lazaridis K, Tzartos S, Brenner T, Duan RS, Luo J, Lindstrom J, Kusner L. Standardization of the experimental autoimmune myasthenia gravis (EAMG) model by immunization of rats with Torpedo californica acetylcholine receptors--Recommendations for methods and experimental designs. Exp Neurol 2015; 270:18-28. [PMID: 25796590 PMCID: PMC4466156 DOI: 10.1016/j.expneurol.2015.03.010] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 03/06/2015] [Accepted: 03/10/2015] [Indexed: 12/21/2022]
Abstract
Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR) is characterized by a chronic, fatigable weakness of voluntary muscles. The production of autoantibodies involves the dysregulation of T cells which provide the environment for the development of autoreactive B cells. The symptoms are caused by destruction of the postsynaptic membrane and degradation of the AChR by IgG autoantibodies, predominantly of the G1 and G3 subclasses. Active immunization of animals with AChR from mammalian muscles, AChR from Torpedo or Electrophorus electric organs, and recombinant or synthetic AChR fragments generates a chronic model of MG, termed experimental autoimmune myasthenia gravis (EAMG). This model covers cellular mechanisms involved in the immune response against the AChR, e.g. antigen presentation, T cell-help and regulation, B cell selection and differentiation into plasma cells. Our aim is to define standard operation procedures and recommendations for the rat EAMG model using purified AChR from the Torpedo californica electric organ, in order to facilitate more rapid translation of preclinical proof of concept or efficacy studies into clinical trials and, ultimately, clinical practice.
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Affiliation(s)
- Mario Losen
- Division Neuroscience, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands.
| | - Pilar Martinez-Martinez
- Division Neuroscience, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | - Peter C Molenaar
- Division Neuroscience, Department of Psychiatry and Neuropsychology, School for Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
| | | | - Socrates Tzartos
- Department of Neurobiology, Hellenic Pasteur Institute, Athens, Greece
| | - Talma Brenner
- Laboratory of Neuroimmunology, Department of Neurology, The Agnes Ginges Center for Human Neurogenetics, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
| | - Rui-Sheng Duan
- Department of Neurology, Shandong Provincial Qianfoshan Hospital, Shandong University, PR China
| | - Jie Luo
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA, USA
| | - Jon Lindstrom
- Department of Neuroscience, University of Pennsylvania Medical School, Philadelphia, PA, USA
| | - Linda Kusner
- Department of Pharmacology & Physiology, The George Washington University, Washington, DC, USA
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10
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Martinez-Martinez P, Molenaar PC, Losen M, Hoffmann C, Stevens J, de Witte LD, van Amelsvoort T, van Os J, Rutten BPF. [Auto-immune disorders as a possible cause of neuropsychiatric syndromes]. Tijdschr Psychiatr 2015; 57:183-191. [PMID: 25856741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
BACKGROUND Changes that occur in the behaviour of voltage-gated ion channels and ligand-gated receptor channels due to gene mutations or auto-immune attack are the cause of channelopathies in the central and peripheral nervous system. Although the relation between molecular channel defects and clinical symptoms has been explained in the case of many neuromuscular channelopathies, the pathophysiology of auto-immunity in neuropsychiatric syndromes is still unclear. AIM To review recent findings regarding neuronal auto-immune reactions in severe neuropsychiatric syndromes. METHOD Using PubMed, we consulted the literature published between 1990 and August 2014 relating to the occurrence of auto-immune antibodies in severe and persistent neuropsychiatric syndromes. RESULTS Auto-antibodies have only limited access to the central nervous system, but if they do enter the system they can, in some cases, cause disease. We discuss recent findings regarding the occurrence of auto-antibodies against ligand-activated receptor channels and potassium channels in neuropsychiatric and neurological syndromes, including schizophrenia and limbic encephalitis. CONCLUSION Although the occurrence of several auto-antibodies in schizophrenia has been confirmed, there is still no proof of a causal relationship in the syndrome. We still have no evidence of the prevalence of auto-immunity in neuropsychiatric syndromes. The discovery that an antibody against an ion channel is associated with some neuropsychiatric disorders may mean that in future it will be possible to treat patients by means of immunosuppression, which could lead to an improvement in a patient's cognitive abilities.
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11
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Affiliation(s)
- Pilar Martinez-Martinez
- Department for Neuroscience, The School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - Peter C Molenaar
- Department for Neuroscience, The School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - Mario Losen
- Department for Neuroscience, The School for Mental Health and Neuroscience, Maastricht University, The Netherlands
| | - Marc H de Baets
- Department for Neuroscience, The School for Mental Health and Neuroscience, Maastricht University, The Netherlands
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12
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Gomez AM, Willcox N, Vrolix K, Hummel J, Nogales-Gadea G, Saxena A, Duimel H, Verheyen F, Molenaar PC, Buurman WA, De Baets MH, Martinez-Martinez P, Losen M. Proteasome inhibition with bortezomib depletes plasma cells and specific autoantibody production in primary thymic cell cultures from early-onset myasthenia gravis patients. J Immunol 2014; 193:1055-1063. [PMID: 24973445 DOI: 10.4049/jimmunol.1301555] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Bortezomib is a potent inhibitor of proteasomes currently used to eliminate malignant plasma cells in multiple myeloma patients. It is also effective in depleting both alloreactive plasma cells in acute Ab-mediated transplant rejection and their autoreactive counterparts in animal models of lupus and myasthenia gravis (MG). In this study, we demonstrate that bortezomib at 10 nM or higher concentrations killed long-lived plasma cells in cultured thymus cells from nine early-onset MG patients and consistently halted their spontaneous production not only of autoantibodies against the acetylcholine receptor but also of total IgG. Surprisingly, lenalidomide and dexamethasone had little effect on plasma cells. After bortezomib treatment, they showed ultrastructural changes characteristic of endoplasmic reticulum stress after 8 h and were no longer detectable at 24 h. Bortezomib therefore appears promising for treating MG and possibly other Ab-mediated autoimmune or allergic disorders, especially when given in short courses at modest doses before the standard immunosuppressive drugs have taken effect.
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Affiliation(s)
- Alejandro M Gomez
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Nick Willcox
- Department of Clinical Neurology, University of Oxford, UK
| | - Kathleen Vrolix
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Jonas Hummel
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Gisela Nogales-Gadea
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands.,Neuromuscular Diseases Unit, Institut de Recerca del Hospital de la Santa Creu i Sant Pau, Universitat Autónoma de Barcelona, Barcelona, Spain
| | - Abhishek Saxena
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Hans Duimel
- ELMI Unit-CRISP, Department of Molecular Cell Biology, Maastricht University, Maastricht, the Netherlands
| | - Fons Verheyen
- ELMI Unit-CRISP, Department of Molecular Cell Biology, Maastricht University, Maastricht, the Netherlands
| | - Peter C Molenaar
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Wim A Buurman
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Marc H De Baets
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Pilar Martinez-Martinez
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
| | - Mario Losen
- School for Mental Health and Neuroscience, Maastricht University, Maastricht, the Netherlands
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13
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Vrolix K, Fraussen J, Losen M, Stevens J, Lazaridis K, Molenaar PC, Somers V, Bracho MA, Le Panse R, Stinissen P, Berrih-Aknin S, Maessen JG, Van Garsse L, Buurman WA, Tzartos SJ, De Baets MH, Martinez-Martinez P. Clonal heterogeneity of thymic B cells from early-onset myasthenia gravis patients with antibodies against the acetylcholine receptor. J Autoimmun 2014; 52:101-12. [PMID: 24439114 DOI: 10.1016/j.jaut.2013.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 12/12/2013] [Indexed: 10/25/2022]
Abstract
Myasthenia gravis (MG) with antibodies against the acetylcholine receptor (AChR-MG) is considered as a prototypic autoimmune disease. The thymus is important in the pathophysiology of the disease since thymus hyperplasia is a characteristic of early-onset AChR-MG and patients often improve after thymectomy. We hypothesized that thymic B cell and antibody repertoires of AChR-MG patients differ intrinsically from those of control individuals. Using immortalization with Epstein-Barr Virus and Toll-like receptor 9 activation, we isolated and characterized monoclonal B cell lines from 5 MG patients and 8 controls. Only 2 of 570 immortalized B cell clones from MG patients produced antibodies against the AChR (both clones were from the same patient), suggesting that AChR-specific B cells are not enriched in the thymus. Surprisingly, many B cell lines from both AChR-MG and control thymus samples displayed reactivity against striated muscle proteins. Striational antibodies were produced by 15% of B cell clones from AChR-MG versus 6% in control thymus. The IgVH gene sequence analysis showed remarkable similarities, concerning VH family gene distribution, mutation frequency and CDR3 composition, between B cells of AChR-MG patients and controls. MG patients showed clear evidence of clonal B cell expansion in contrast to controls. In this latter aspect, MG resembles multiple sclerosis and clinically isolated syndrome, but differs from systemic lupus erythematosus. Our results support an antigen driven immune response in the MG thymus, but the paucity of AChR-specific B cells, in combination with the observed polyclonal expansions suggest a more diverse immune response than expected.
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Affiliation(s)
- Kathleen Vrolix
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Judith Fraussen
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Mario Losen
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Jo Stevens
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | | | - Peter C Molenaar
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Veerle Somers
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Maria Alma Bracho
- Centre Superior d'Investigació en Salut Pública (CSISP), Àrea de Genòmica i Salut, Conselleria de Sanitat, Generalitat Valenciana, València, Spain; Institut "Cavanilles" de Biodiversitat i Biologia Evolutiva (ICBiBE), Universitat de València, València, Spain; Centro de Investigación Biomédica en Red de Epidemiología y Salud Pública (CIBERESP), Ministerio de Ciencia e Innovación, Spain
| | - Rozen Le Panse
- UPMC UM 76/INSERM U974/CNRS UMR7215/Institute of Myology, 105 Bd de l'hôpital, Paris, France
| | - Piet Stinissen
- Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Sonia Berrih-Aknin
- UPMC UM 76/INSERM U974/CNRS UMR7215/Institute of Myology, 105 Bd de l'hôpital, Paris, France
| | - Jos G Maessen
- Department of Cardiothoracic Surgery, University Hospital, Maastricht, The Netherlands
| | - Leen Van Garsse
- Department of Cardiothoracic Surgery, University Hospital, Maastricht, The Netherlands
| | - Wim A Buurman
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands
| | - Socrates J Tzartos
- Department of Biochemistry, Hellenic Pasteur Institute, GR 11521 Athens, Greece
| | - Marc H De Baets
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands; Neuroimmunology group, Biomedical Research Institute and Transnationale Universiteit Limburg, School of Life Sciences, Hasselt University, Diepenbeek, Belgium
| | - Pilar Martinez-Martinez
- Department of Neuroscience, School of Mental Health and Neuroscience, Faculty of Health, Medicine and Life Sciences, Maastricht University, Universiteitssingel 50, P.O. Box 616, 6200 MD Maastricht, The Netherlands.
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Bode GH, Losen M, Buurman WA, Veerhuis R, Molenaar PC, Steinbusch HWM, De Baets MH, Daha MR, Martinez-Martinez P. Complement activation by ceramide transporter proteins. J Immunol 2014; 192:1154-61. [PMID: 24395916 DOI: 10.4049/jimmunol.1301673] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
C1q is the initiator of the classical complement pathway and, as such, is essential for efficient opsonization and clearance of pathogens, altered self-structures, and apoptotic cells. The ceramide transporter protein (CERT) and its longer splicing isoform CERTL are known to interact with extracellular matrix components, such as type IV collagen, and with the innate immune protein serum amyloid P. In this article, we report a novel function of CERT in the innate immune response. Both CERT isoforms, when immobilized, were found to bind the globular head region of C1q and to initiate the classical complement pathway, leading to activation of C4 and C3, as well as generation of the membrane attack complex C5b-9. In addition, C1q was shown to bind to endogenous CERTL on the surface of apoptotic cells. These results demonstrate the role of CERTs in innate immunity, especially in the clearance of apoptotic cells.
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Affiliation(s)
- Gerard H Bode
- Division of Neuroscience, School for Mental Health and Neuroscience, Faculty of Health, Medicine, and Life Sciences, Maastricht University, 6200 MD Maastricht, The Netherlands
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15
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Martinez-Martinez P, Molenaar PC, Losen M, Stevens J, Baets MHD, Szoke A, Honnorat J, Tamouza R, Leboyer M, Os JV, Rutten BPF. Autoantibodies to neurotransmitter receptors and ion channels: from neuromuscular to neuropsychiatric disorders. Front Genet 2013; 4:181. [PMID: 24065983 PMCID: PMC3778371 DOI: 10.3389/fgene.2013.00181] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 08/27/2013] [Indexed: 01/17/2023] Open
Abstract
Changes of voltage-gated ion channels and ligand-gated receptor channels caused by mutation or autoimmune attack are the cause of so-called channelopathies in the central and peripheral nervous system. We present the pathophysiology of channelopathies of the neuromuscular junction in terms of loss-of-function and gain-of-function principles. Autoantibodies generally have reduced access to the central nervous system, but in some cases this is enough to cause disease. A review is provided of recent findings implicating autoantibodies against ligand-activated receptor channels and potassium channels in psychiatric and neurological disorders, including schizophrenia and limbic encephalitis. The emergence of channelopathy-related neuropsychiatric disorders has implications for research and practice.
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Affiliation(s)
- Pilar Martinez-Martinez
- Department of Psychiatry and Psychology, School for Mental Health and Neuroscience, Maastricht University Maastricht, Netherlands
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16
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Verschuuren JJ, Huijbers MG, Plomp JJ, Niks EH, Molenaar PC, Martinez-Martinez P, Gomez AM, De Baets MH, Losen M. Pathophysiology of myasthenia gravis with antibodies to the acetylcholine receptor, muscle-specific kinase and low-density lipoprotein receptor-related protein 4. Autoimmun Rev 2013; 12:918-23. [DOI: 10.1016/j.autrev.2013.03.001] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2013] [Indexed: 01/13/2023]
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17
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Gomez AM, Vanheel A, Losen M, Molenaar PC, De Baets MH, Noben JP, Hellings N, Martinez-Martinez P. Proteomic analysis of rat tibialis anterior muscles at different stages of experimental autoimmune myasthenia gravis. J Neuroimmunol 2013; 261:141-5. [PMID: 23791150 DOI: 10.1016/j.jneuroim.2013.05.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2013] [Accepted: 05/10/2013] [Indexed: 12/28/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disease in which autoantibodies, most commonly directed against the acetylcholine receptor (AChR), impair neuromuscular transmission and cause muscle weakness. In this study, we utilized two-dimensional difference in-gel electrophoresis (2D-DIGE) to analyze the muscle's proteomic profile at different stages of experimental autoimmune myasthenia gravis (EAMG). We identified twenty-two differentially expressed proteins, mainly related to metabolic and stress-response pathways. Interestingly, these identified proteins have also been associated with other contraction-impairing muscle pathologies (e.g. inclusion body myositis), suggesting a similar response of the muscle to such conditions.
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Affiliation(s)
- Alejandro M Gomez
- Division Neuroscience, School for Mental Health and Neuroscience, Maastricht University, 6200 MD Maastricht, the Netherlands
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18
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Gomez AM, Willcox N, Molenaar PC, Buurman W, Martinez-Martinez P, De Baets MH, Losen M. Targeting plasma cells with proteasome inhibitors: possible roles in treating myasthenia gravis? Ann N Y Acad Sci 2012; 1274:48-59. [DOI: 10.1111/j.1749-6632.2012.06824.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Mencarelli C, Bode GH, Losen M, Kulharia M, Molenaar PC, Veerhuis R, Steinbusch HWM, De Baets MH, Nicolaes GAF, Martinez-Martinez P. Goodpasture antigen-binding protein/ceramide transporter binds to human serum amyloid P-component and is present in brain amyloid plaques. J Biol Chem 2012; 287:14897-911. [PMID: 22396542 DOI: 10.1074/jbc.m111.299545] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Serum amyloid P component (SAP) is a non-fibrillar glycoprotein belonging to the pentraxin family of the innate immune system. SAP is present in plasma, basement membranes, and amyloid deposits. This study demonstrates, for the first time, that the Goodpasture antigen-binding protein (GPBP) binds to human SAP. GPBP is a nonconventional Ser/Thr kinase for basement membrane type IV collagen. Also GPBP is found in plasma and in the extracellular matrix. In the present study, we demonstrate that GPBP specifically binds SAP in its physiological conformations, pentamers and decamers. The START domain in GPBP is important for this interaction. SAP and GPBP form complexes in blood and partly colocalize in amyloid plaques from Alzheimer disease patients. These data suggest the existence of complexes of SAP and GPBP under physiological and pathological conditions. These complexes are important for understanding basement membrane, blood physiology, and plaque formation in Alzheimer disease.
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Affiliation(s)
- Chiara Mencarelli
- Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, P.O. Box 616, 6200 MD Maastricht, The Netherlands
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Hillary FG, Medaglia JD, Gates K, Molenaar PC, Slocomb J, Peechatka A, Good DC. Examining working memory task acquisition in a disrupted neural network. ACTA ACUST UNITED AC 2011; 134:1555-70. [PMID: 21571783 DOI: 10.1093/brain/awr043] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
There is mounting literature that examines brain activation during tasks of working memory in individuals with neurological disorders such as traumatic brain injury. These studies represent a foundation for understanding the functional brain changes that occur after moderate and severe traumatic brain injury, but the focus on topographical brain-'activation' differences ignores potential alterations in how nodes communicate within a distributed neural network. The present study makes use of the most recently developed connectivity modelling (extended-unified structural equation model) to examine performance during a well-established working-memory task (the n-back) in individuals sustaining moderate and severe traumatic brain injury. The goal is to use the findings observed in topographical activation analysis as the basis for second-level effective connectivity modelling. Findings reveal important between-group differences in within-hemisphere connectivity during task acquisition, with the control sample demonstrating rapid within-left hemisphere connectivity increases and the traumatic brain injury sample demonstrating consistently elevated within-right hemisphere connectivity. These findings also point to important maturational effects from 'early' to 'late' during task performance, including diminished right prefrontal cortex involvement and an anterior to posterior shift in connectivity with increased task exposure. We anticipate that this approach to functional imaging data analysis represents an important future direction for understanding how neural plasticity is expressed in brain disorders.
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Affiliation(s)
- Frank G Hillary
- Department of Psychology, Pennsylvania State University, 223 Bruce V. Moore Building, University Park, PA 16802, USA.
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21
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Vrolix K, Niks EH, Le Panse R, van Ostaijen-ten Dam MM, Muris AH, Jol-van der Zijde CM, van Tol MJ, Losen M, Molenaar PC, van Zoelen EJ, Berrih-Aknin S, De Baets MH, Verschuuren JJ, Martínez-Martínez P. Reduced thymic expression of ErbB receptors without auto-antibodies against synaptic ErbB in myasthenia gravis. J Neuroimmunol 2011; 232:158-65. [DOI: 10.1016/j.jneuroim.2010.10.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2010] [Revised: 09/27/2010] [Accepted: 10/21/2010] [Indexed: 11/15/2022]
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Gomez AM, Vrolix K, Martínez-Martínez P, Molenaar PC, Phernambucq M, van der Esch E, Duimel H, Verheyen F, Voll RE, Manz RA, De Baets MH, Losen M. Proteasome inhibition with bortezomib depletes plasma cells and autoantibodies in experimental autoimmune myasthenia gravis. J Immunol 2011; 186:2503-13. [PMID: 21239719 DOI: 10.4049/jimmunol.1002539] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Bortezomib, an inhibitor of proteasomes, has been reported to reduce autoantibody titers and to improve clinical condition in mice suffering from lupus-like disease. Bortezomib depletes both short- and long-lived plasma cells; the latter normally survive the standard immunosuppressant treatments targeting T and B cells. These findings encouraged us to test whether bortezomib is effective for alleviating the symptoms in the experimental autoimmune myasthenia gravis (EAMG) model for myasthenia gravis, a disease that is characterized by autoantibodies against the acetylcholine receptor (AChR) of skeletal muscle. Lewis rats were immunized with saline (control, n = 36) or Torpedo AChR (EAMG, n = 54) in CFA in the first week of an experimental period of 8 wk. After immunization, rats received twice a week s.c. injections of bortezomib (0.2 mg/kg in saline) or saline injections. Bortezomib induced apoptosis in bone marrow cells and reduced the amount of plasma cells in the bone marrow by up to 81%. In the EAMG animals, bortezomib efficiently reduced the rise of anti-AChR autoantibody titers, prevented ultrastructural damage of the postsynaptic membrane, improved neuromuscular transmission, and decreased myasthenic symptoms. This study thus underscores the potential of the therapeutic use of proteasome inhibitors to target plasma cells in Ab-mediated autoimmune diseases.
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Affiliation(s)
- Alejandro M Gomez
- Neuroimmunology Group, Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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23
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Gomez AM, Van Den Broeck J, Vrolix K, Janssen SP, Lemmens MAM, Van Der Esch E, Duimel H, Frederik P, Molenaar PC, Martínez-Martínez P, De Baets MH, Losen M. Antibody effector mechanisms in myasthenia gravis-pathogenesis at the neuromuscular junction. Autoimmunity 2010; 43:353-70. [PMID: 20380584 DOI: 10.3109/08916930903555943] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Myasthenia gravis (MG) is an autoimmune disorder caused by autoantibodies that are either directed to the muscle nicotinic acetylcholine receptor (AChR) or to the muscle-specific tyrosine kinase (MuSK). These autoantibodies define two distinct subforms of the disease-AChR-MG and MuSK-MG. Both AChR and MuSK are expressed on the postsynaptic membrane of the neuromuscular junction (NMJ), which is a highly specialized region of the muscle dedicated to receive and process signals from the motor nerve. Autoantibody binding to proteins of the postsynaptic membrane leads to impaired neuromuscular transmission and muscle weakness. Pro-inflammatory antibodies of the human IgG1 and IgG3 subclass modulate the AChR, cause complement activation, and attract lymphocytes; together acting to decrease levels of the AChR and AChR-associated proteins and to reduce postsynaptic folding. In patients with anti-MuSK antibodies, there is no evidence of loss of junctional folds and no apparent loss of AChR density. Anti-MuSK antibodies are predominantly of the IgG4 isotype, which functionally differs from other IgG subclasses in its anti-inflammatory activity. Moreover, IgG4 undergoes a posttranslational modification termed Fab arm exchange that prevents cross-linking of antigens. These findings suggest that MuSK-MG may be different in etiological and pathological mechanisms from AChR-MG. The effector functions of IgG subclasses on synapse structure and function are discussed in this review.
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Affiliation(s)
- Alejandro M Gomez
- Neuroimmunology Group, Department of Neuroscience, School of Mental Health and Neuroscience, Maastricht University, Maastricht, The Netherlands
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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25
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ter Beek WP, Martínez-Martínez P, Losen M, de Baets MH, Wintzen AR, Verschuuren JJGM, Niks EH, van Duinen SG, Vincent A, Molenaar PC. The effect of plasma from muscle-specific tyrosine kinase myasthenia patients on regenerating endplates. Am J Pathol 2009; 175:1536-44. [PMID: 19745065 DOI: 10.2353/ajpath.2009.090040] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Muscle-specific tyrosine kinase (MuSK) is essential for clustering of acetylcholine receptors (AChRs) at embryogenesis and likely also important for maintaining synaptic structure in adult muscle. In 5 to 7% of myasthenia gravis (MG) cases, the patients' blood contains antibodies to MuSK. To investigate the effect of MuSK-MG antibody on synapse regeneration, notexin was used to induce damage to the flexor digitorum brevis muscle. We administered aliquots of MuSK-MG patients' plasma to the flexor digitorum brevis twice daily for a period up to 21 days, and muscles were investigated ex vivo in contraction experiments. AChR levels were measured with (125)I-alpha-bungarotoxin, and endplates were studied with quantitative immunohistochemistry. In normal muscles and in 14-day regenerated muscles, MuSK plasma caused impairment of nerve stimulus-induced contraction in the presence of 0.35 and 0.5 mmol/L Ca(2+) with or without 100 to 400 nmol/L tubocurarine. Endplate size was decreased in regenerated muscles relative to controls; however, we did not observe such differences in muscle not treated with notexin. MuSK plasma had no effect on the amount and turnover rate of AChRs. Our results suggest that anti-MuSK antibodies influence the activity of MuSK molecules without reducing their number, thereby diminishing the size of the endplate and affecting the functioning of AChRs.
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Affiliation(s)
- W Pascale ter Beek
- Neurophysiology Section, Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
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26
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Faber CG, Molenaar PC, Vles JSH, Bonifati DM, Verschuuren JJGM, van Doorn PA, Kuks JBM, Wokke JHJ, Beeson D, De Baets M. AChR deficiency due to epsilon-subunit mutations: two common mutations in the Netherlands. J Neurol 2009; 256:1719-23. [PMID: 19544078 PMCID: PMC2758211 DOI: 10.1007/s00415-009-5190-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 04/23/2009] [Accepted: 05/18/2009] [Indexed: 11/30/2022]
Abstract
Congenital myasthenic syndromes are a clinically and genetically heterogeneous group of hereditary disorders affecting neuromuscular transmission. We have identified mutations within the acetylcholine receptor (AChR) ε-subunit gene underlying congenital myasthenic syndromes in nine patients (seven kinships) of Dutch origin. Previously reported mutations ε1369delG and εR311Q were found to be common; ε1369delG was present on at least one allele in seven of the nine patients, and εR311Q in six. Phenotypes ranged from relatively mild ptosis and external ophthalmoplegia to generalized myasthenia. The common occurrence of εR311Q and ε1369delG suggests a possible founder for each of these mutations originating in North Western Europe, possibly in Holland. Knowledge of the ethnic or geographic origin within Europe of AChR deficiency patients can help in targeting genetic screening and it may be possible to provide a rapid genetic diagnosis for patients of Dutch origin by screening first for εR311Q and ε1369delG.
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Affiliation(s)
- Catharina G Faber
- Department of Neurology, Maastricht University Medical Centre, PO Box 5800, 6202 AZ, Maastricht, The Netherlands.
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Bullens RWM, Halstead SK, O'Hanlon GM, Veitch J, Molenaar PC, Willison HJ, Plomp JJ. Concanavalin A inhibits pathophysiological effects of anti-ganglioside GQ1b antibodies at the mouse neuromuscular synapse. Muscle Nerve 2005; 31:751-60. [PMID: 15793847 DOI: 10.1002/mus.20327] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Anti-GQ1b antibodies are present in the Miller Fisher syndrome (MFS), a monophasic neuropathy characterized by ataxia, areflexia, ophthalmoplegia, and sometimes cranial muscle weakness. We have previously shown, at the mouse neuromuscular junction (NMJ) ex vivo, that anti-GQ1b antibodies, through complement classic pathway activation, block synaptic transmission in a way that resembles the effect of the pore-forming alpha-latrotoxin (alphaLTx). In order to clarify the mechanism of these alphaLTx-like effects, including possible involvement of the alternative and mannose-binding protein complement pathways, we studied the effects of concanavalin A (ConA), a lectin known to block the action of alphaLTx, immunoglobulins, and early complement components. With electrophysiological, immunohistological, and bioassay experiments, we showed that the alphaLTx-like effects of anti-GQ1b antibody and complement were inhibited by pre- and coincubation with ConA. However, ConA was not able to inhibit evolution of alphaLTx-like effects when coincubated upon addition of complement at NMJs that had already bound anti-GQ1b antibody. Our data suggest that the mannose-binding protein pathway is not involved in the alphaLTx-like effect and that the inhibiting effect of ConA principally arises through interference with presynaptic binding of anti-GQ1b antibody. In control experiments, ConA prevented the neuroexocytotic effects of alphaLTx, indicating that alphaLTx receptors were inhibited under these conditions. We conclude that, although the physiological effects at the NMJ of anti-GQ1b antibody and alphaLTx are very similar, the activity of anti-GQ1b antibody is not mediated through activation of alphaLTx receptors, but rather is caused by direct presynaptic membrane damage through classic complement pathway activation.
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Affiliation(s)
- Roland W M Bullens
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands
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28
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Hoebeek FE, Stahl JS, van Alphen AM, Schonewille M, Luo C, Rutteman M, van den Maagdenberg AMJM, Molenaar PC, Goossens HHLM, Frens MA, De Zeeuw CI. Increased noise level of purkinje cell activities minimizes impact of their modulation during sensorimotor control. Neuron 2005; 45:953-65. [PMID: 15797555 DOI: 10.1016/j.neuron.2005.02.012] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2004] [Revised: 09/27/2004] [Accepted: 02/02/2005] [Indexed: 11/24/2022]
Abstract
While firing rate is well established as a relevant parameter for encoding information exchanged between neurons, the significance of other parameters is more conjectural. Here, we show that regularity of neuronal spike activities affects sensorimotor processing in tottering mutants, which suffer from a mutation in P/Q-type voltage-gated calcium channels. While the modulation amplitude of the simple spike firing rate of their floccular Purkinje cells during optokinetic stimulation is indistinguishable from that of wild-types, the regularity of their firing is markedly disrupted. The gain and phase values of tottering's compensatory eye movements are indistinguishable from those of flocculectomized wild-types or from totterings with the flocculus treated with P/Q-type calcium channel blockers. Moreover, normal eye movements can be evoked in tottering when the flocculus is electrically stimulated with regular spike trains mimicking the firing pattern of normal simple spikes. This study demonstrates the importance of regularity of firing in Purkinje cells for neuronal information processing.
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Affiliation(s)
- F E Hoebeek
- Department of Neuroscience, Erasmus MC, Dr. Molenwaterplein 50, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands.
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29
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Plomp JJ, van den Maagdenberg AM, Ferrari MD, Frants RR, Molenaar PC. Transmitter Release Deficits at the Neuromuscular Synapse of Mice with Mutations in the Cav2.1 (α1A) Subunit of the P/Q-Type Ca2+Channel. Ann N Y Acad Sci 2003; 998:29-32. [PMID: 14592860 DOI: 10.1196/annals.1254.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- J J Plomp
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
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30
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Bullens RWM, O'Hanlon GM, Wagner E, Molenaar PC, Furukawa K, Furukawa K, Plomp JJ, Willison HJ. Roles of Complex Gangliosides at the Neuromuscular Junction. Ann N Y Acad Sci 2003; 998:401-3. [PMID: 14592906 DOI: 10.1196/annals.1254.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- R W M Bullens
- Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands
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31
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Leenders AGM, van den Maagdenberg AMJM, Lopes da Silva FH, Sheng ZH, Molenaar PC, Ghijsen WEJM. Neurotransmitter release from tottering mice nerve terminals with reduced expression of mutated P- and Q-type Ca2+-channels. Eur J Neurosci 2002; 15:13-8. [PMID: 11860502 DOI: 10.1046/j.0953-816x.2001.01839.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Neurotransmitter release is triggered by Ca2+-influx through multiple sub-types of high voltage-activated Ca2+-channels. Tottering mice have a mutation in the alpha1A pore-forming subunit of P- and Q-type Ca2+-channels, two prominent sub-types that regulate transmitter release from central nerve terminals. Immunoblotting analysis of purified forebrain terminals from tottering mice revealed an 85% reduction in the protein expression level of the mutated alpha1A subunit compared to expression of the alpha1A subunit in wild-type terminals. In contrast, the expression of the alpha1B subunit of the N-type Ca2+-channels was unchanged. Release of the amino acids glutamate and GABA and of the neuropeptide cholecystokinin (CCK) induced by a short (100 ms) depolarization pulse was unchanged in the terminals of tottering mice. Studies using specific blockers of Ca2+-channels however, revealed a reduced contribution of P- and Q-type Ca2+-channels to glutamate and cholecystokinin release, whereas a greater reliance on N-type Ca2+-channels for release of these transmitters was observed. In contrast, the contribution of the P-, Q- and N-type Ca2+-channels to the release of GABA was not altered in tottering mice. These results indicate that the expression of the alpha1A subunit was decreased in terminals from tottering mice, and that a decreased contribution of P- and Q-type Ca2+-channels to the release of glutamate and cholecystokinin was functionally compensated by an increased contribution of N-type Ca2+-channels.
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Affiliation(s)
- A G Miriam Leenders
- Swammerdam Institute for Life Sciences, Section Neurobiology, Faculty of Science, University of Amsterdam, Kruislaan 320, 1090 GB Amsterdam, The Netherlands
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32
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van Beijsterveldt CE, van Baal GC, Molenaar PC, Boomsma DI, de Geus EJ. Stability of genetic and environmental influences on P300 amplitude: a longitudinal study in adolescent twins. Behav Genet 2001; 31:533-43. [PMID: 11838531 DOI: 10.1023/a:1013389226795] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
This study examined the stability of genetic and environmental influences on individual differences in P300 amplitude during adolescence. The P300 component is an event-related brain potential (ERP) that has attracted much attention as a biological marker for disturbed cognitive processing in psychopathology. Understanding the genetics of this biological marker may contribute to understanding the genetics of the associated psychopathologies. In a group of 213 adolescent twin pairs, the P300 component was measured twice, the first time at age 16 and the second time 18 months later. A large part of the variance of the P300 amplitude could be explained by familial factors, with estimates ranging from 30% to 81%. Whether the familial resemblance was due to genetic or shared environmental factors depended on sex. For males, genetic factors explained familial resemblance in P300 amplitude, but for females such resemblance was likely due to shared environmental factors. The phenotypic stability of the P300 amplitude from 16 to 18 years was high in both sexes, and stability could be attributed largely to the same familial factors. There was no evidence that new familial influences emerged at age 18.
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33
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Houtveen JH, Molenaar PC. Comparison between the Fourier and Wavelet methods of spectral analysis applied to stationary and nonstationary heart period data. Psychophysiology 2001; 38:729-35. [PMID: 11577896] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The aim of this study was to assess the error made by violating the assumption of stationarity when using Fourier analysis for spectral decomposition of heart period power. A comparison was made between using Fourier and Wavelet analysis (the latter being a relatively new method without the assumption of stationarity). Both methods were compared separately for stationary and nonstationary segments. An ambulatory device was used to measure the heart period data of 40 young and healthy participants during a psychological stress task and during periods of rest. Surprisingly small differences (<1%) were found between the results of both methods, with differences being slightly larger for the nonstationary segments. It is concluded that both methods perform almost identically for computation of heart period power values. Thus, the Wavelet method is only superior for analyzing heart period data when additional analyses in the time-frequency domain are required.
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Affiliation(s)
- J H Houtveen
- Department of Health Psychology, University of Utrecht, The Netherlands.
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34
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Plomp JJ, van den Maagdenberg AM, Molenaar PC, Frants RR, Ferrari MD. Mutant P/Q-type calcium channel electrophysiology and migraine. Curr Opin Investig Drugs 2001; 2:1250-60. [PMID: 11717812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The pathophysiological mechanisms of migraine are not yet very well understood. The gene CACNA1A, coding for the alpha 1A subunit of neuronal P/Q-type Ca2+ channels is mutated in the rare Mendelian inherited variant, familial hemiplegic migraine. This finding suggests a role for disturbed neuronal Ca2+ influx and/or homeostasis in the pathophysiology of migraine. It has stimulated in vitro electrophysiological investigations into the function of mutant human and mouse P/Q-type channels at cell bodies and synapses. A complex picture has emerged from this work, showing that different CACNA1A mutations lead to different effects on Ca2+ channel behavior and that synaptic transmission may become affected. We will review these studies and discuss the possible implications for the understanding of migraine pathophysiology.
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Affiliation(s)
- J J Plomp
- Department of Neurology, Department of Physiology and Medical Pharmacology, Leiden University Medical Center, POB 9600, 2300 RC, Leiden, The Netherlands.
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35
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Abstract
Through the application of finite mixture distribution models, we investigated the existence of distinct modes of behavior in learning a simple discrimination. The data were obtained in a repeated measures study in which subjects aged 6 to 10 years carried out a simple discrimination learning task. In contrast to distribution models of exclusively rational learners or exclusively incremental learners, a mixture distribution model of rational learners and slow learners was found to fit the data of all measurement occasions and all age groups. Hence, the finite mixture distribution analysis provides strong support for the existence of distinct modes of learning behavior. The results of a second experiment support this conclusion by crossvalidation of the models that fit the data of the first experiment. The effect of verbally labeling the values on the relevant stimulus dimension and the consistency of behavior over measurement occasions are related to the mixture model estimates.
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Affiliation(s)
- M E Raijmakers
- Department of Develomental Psychology, University of Amsterdam, The Netherlands.
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36
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Abstract
A method is described to derive source and conductivity estimates in a simultaneous MEG and EEG source analysis. In addition the covariance matrix of the estimates is derived. Simulation studies with a concentric spheres model and a more realistic boundary element model indicate that this method has several advantages, even if only a few EEG sensors are added to a MEG configuration. First, a simultaneous analysis profits from the 'preferred' location directions of MEG and EEG. Second, deep sources can be estimated quite accurately, which is an advantage compared to MEG. Third, superficial sources profit from accurate MEG location and from accurate EEG moment. Fourth, the radial source component can be estimated, which is an advantage compared to MEG. Fifth, the conductivities can be estimated. It is shown that conductivity estimation gives a substantial increase in precision, even if the conductivities are not identified appropriately. An illustrative analysis of empirical data supports these findings.
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Affiliation(s)
- H M Huizenga
- Department of Psychology, University of Amsterdam, The Netherlands.
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37
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Waldorp LJ, Huizenga HM, Dolan CV, Molenaar PC. Estimated generalized least squares electromagnetic source analysis based on a parametric noise covariance model. IEEE Trans Biomed Eng 2001; 48:737-41. [PMID: 11396604 DOI: 10.1109/10.923793] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Estimated generalized least squares (EGLS) electromagnetic source analysis is used to downweight noisy and correlated data. Standard EGLS requires many trials to accurately estimate the noise covariances and, thus, the source parameters. Alternatively, the noise covariances can be modeled parametrically. Only the parameters of the model describing the noise covariances need to be estimated and, therefore, less trials are required. This method is referred to as parametric egls (PEGLS). In this paper, PEGLS is developed and its performance is tested in a simulation study and in a pseudoempirical study.
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Affiliation(s)
- L J Waldorp
- Department of Psychology, University of Amsterdam, The Netherlands.
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38
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O'Hanlon GM, Plomp JJ, Chakrabarti M, Morrison I, Wagner ER, Goodyear CS, Yin X, Trapp BD, Conner J, Molenaar PC, Stewart S, Rowan EG, Willison HJ. Anti-GQ1b ganglioside antibodies mediate complement-dependent destruction of the motor nerve terminal. Brain 2001; 124:893-906. [PMID: 11335692 DOI: 10.1093/brain/124.5.893] [Citation(s) in RCA: 134] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Miller-Fisher syndrome is an autoimmune neuropathy characterized by ataxia, areflexia and ophthalmoplegia, and in the majority of cases the presence of high titres of anti-GQ1b ganglioside antibodies. In an ex vivo model, human and mouse anti-GQ1b antibodies have been shown previously to induce a complement-dependent alpha-latrotoxin-like effect on the murine motor endplate, i.e. they bring about massive quantal release of acetylcholine and eventually block neuromuscular transmission. Using immunofluorescence microscopy with image analysis, we show here that the late stages of this electrophysiological effect temporally coincide with the loss of heavy neurofilament (200 kDa) and type III beta-tubulin immunostaining and structural breakdown of the nerve terminal, as demonstrated by electron microscopy. Ultrastructurally, axon terminals were disorganized, depleted of vesicles, and subdivided by the infiltrating processes of capping Schwann cells. These findings provide clear pathological evidence to support a role for anti-ganglioside antibodies in mediating nerve terminal injury and further advance the view that this site may be of importance as a target in some human neuropathies.
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Affiliation(s)
- G M O'Hanlon
- University Department of Neurology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
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39
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Abstract
Three methods for computing confidence intervals (CIs) of hidden Markov model parameters are compared in the context of 'long' time series, T > 100, namely likelihood profiling, bootstrapping and CIs based on a finite-differences approximation to the Hessian. First it is shown that with 'long' time series computing the exact Hessian is not feasible. In simulation studies quadratic and cubic interpolation polynomials for the likelihood profiles are compared. Likelihood profiling and bootstrapping produce similar CIs, whereas the CIs from the finite-differences approximation of the Hessian are mostly too small.
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Affiliation(s)
- I Visser
- Department of Psychology, University of Amsterdam, The Netherlands.
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40
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Abstract
Miller Fisher syndrome (MFS) is clinically characterized by ataxia, areflexia, and ophthalmoplegia, and is associated with serum anti-GQ1b-ganglioside antibodies. We have previously shown that anti-GQ1b antibodies induce complement-dependent, alpha-latrotoxin-like effects at mouse neuromuscular junctions (NMJs) in vitro. This effect comprises a massive increase in spontaneous quantal acetylcholine (ACh) release, accompanied by block of evoked release and muscle paralysis. This mechanism may contribute to the motor features of MFS. Whether the block of evoked ACh release is a primary effect of anti-GQ1b antibodies or occurs secondary to massive complement-dependent spontaneous release is unknown. Using conventional micro-electrode methods, we measured in detail ACh release evoked with low- and high-rate nerve stimulation, and studied the effect on it of a purified MFS IgG and a mouse monoclonal anti-GQ1b IgM (without added complement). We found that evoked transmitter release was unaffected. Control experiments proved binding of anti-GQ1b antibody at the NMJ. We conclude that the block of nerve-evoked ACh release at the NMJ is not a primary effect of anti-GQ1b antibodies, but is dependent on antibody-mediated complement activation. It remains to be determined whether the block of nerve-evoked ACh release is the consequence of massive spontaneous ACh release or occurs as a concomitant event.
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Affiliation(s)
- R W Bullens
- Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.
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41
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Garst H, Frese M, Molenaar PC. The temporal factor of change in stressor-strain relationships: a growth curve model on a longitudinal study in east Germany. J Appl Psychol 2000; 85:417-38. [PMID: 10900816 DOI: 10.1037/0021-9010.85.3.417] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Several theoretical models describing how stressor-strain relationships unfold in time (e.g., M. Frese & D. Zapf, 1988) were tested with a longitudinal study, with 6 measurement waves, using multivariate latent growth curve models. The latent growth curve model made it possible to decompose trait and state components of strains and to show that both trait and state components are affected by work stressors. Because East Germany constitutes a high-change environment, it is an appropriate setting in which to study the relationship between work stressors and strains. The results showed that both the state and trait components of strains were affected by stressors. For example, individual trends in uncertainty (stressor) and worrying (strain) were related, whereas worrying also showed a short-term relationship with time pressure (another stressor). In particular, the decomposition into trait and state components was only possible with the growth curve method that was used.
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Affiliation(s)
- H Garst
- Department of Psychology, University of Amsterdam, The Netherlands
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42
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Plomp JJ, Vergouwe MN, Van den Maagdenberg AM, Ferrari MD, Frants RR, Molenaar PC. Abnormal transmitter release at neuromuscular junctions of mice carrying the tottering alpha(1A) Ca(2+) channel mutation. Brain 2000; 123 Pt 3:463-71. [PMID: 10686170 DOI: 10.1093/brain/123.3.463] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neurotransmitter release at many synapses is regulated by P/Q-type Ca(2+) channels containing the alpha(1A) pore-forming subunit. Mutations in alpha(1A) cause cerebral disorders including familial hemiplegic migraine (FHM) and ataxia in humans. Tottering (tg) alpha(1A) mutant mice display ataxia and epilepsy. It is not known whether alpha(1A) mutations induce impairment of synaptic function, which could underlie the symptoms of these cerebral disorders. To assess whether alpha(1A) mutations influence neurotransmitter release, we studied P-type Ca(2+) channel-mediated acetylcholine (ACh) release at tg neuromuscular junctions (NMJs) with micro-electrode measurements of synaptic potentials. We found a Ca(2+)-, Mg(2+)- and K(+)-dependent increase of spontaneous ACh release at both homo- and heterozygote tg NMJs. Furthermore, there was increased run-down of high-rate evoked release at homozygous tg NMJs. In isotonic contraction experiments this led to block of synaptic transmission at lower concentrations of the ACh antagonist tubocurarine than were needed in wild-type muscles. Our results suggest that in tg motor nerve terminals there is increased influx of Ca(2+) under resting conditions. This study shows that functional consequences of alpha(1A) mutations causing cerebral disorders can be characterized at the NMJ.
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Affiliation(s)
- J J Plomp
- Department of Physiology, Leiden University Medical Centre, Leiden, The Netherlands
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Abstract
A method for estimating the random coefficients model using covariance structure modeling is presented. This method allows one to estimate both fixed and random effects. A way of translating the general linear mixed model into a structural equation modeling (SEM) format is presented. In particular, a LISREL setup for the multiple group linear latent growth curve model is illustrated with suggestions on ways to parameterize more complex models. To illustrate the procedure, we apply the method to both simulated and real data. The method is shown to recover the simulated parameter values. Results and interpretation for the Belsky and Rovine (1990) marriage data are presented. Other applications of the more general model are suggested.
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44
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Goodyear CS, O'Hanlon GM, Plomp JJ, Wagner ER, Morrison I, Veitch J, Cochrane L, Bullens RW, Molenaar PC, Conner J, Willison HJ. Monoclonal antibodies raised against Guillain-Barré syndrome-associated Campylobacter jejuni lipopolysaccharides react with neuronal gangliosides and paralyze muscle-nerve preparations. J Clin Invest 1999. [PMID: 10491405 DOI: 10.1172/jci6837e1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Guillain-Barré syndrome and its variant, Miller-Fisher syndrome, are acute, postinfectious, autoimmune neuropathies that frequently follow Campylobacter jejuni enteritis. The pathogenesis is believed to involve molecular mimicry between sialylated epitopes on C. jejuni LPSs and neural gangliosides. More than 90% of Miller-Fisher syndrome cases have serum anti-GQ1b and anti-GT1a ganglioside antibodies that may also react with other disialylated gangliosides including GD3 and GD1b. Structural studies on LPS from neuropathy-associated C. jejuni strains have revealed GT1a-like and GD3-like core oligosaccharides. To determine whether this structural mimicry results in pathogenic autoantibodies, we immunized mice with GT1a/GD3-like C. jejuni LPS and then cloned mAb's that reacted with both the immunizing LPS and GQ1b/GT1a/GD3 gangliosides. Immunohistology demonstrated antibody binding to ganglioside-rich sites including motor nerve terminals. In ex vivo electrophysiological studies of nerve terminal function, application of antibodies either ex vivo or in vivo via passive immunization induced massive quantal release of acetylcholine, followed by neurotransmission block. This effect was complement-dependent and associated with extensive deposits of IgM and C3c at nerve terminals. These data provide strong support for the molecular mimicry hypothesis as a mechanism for the induction of cross-reactive pathogenic anti-ganglioside/LPS antibodies in postinfectious neuropathies.
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Affiliation(s)
- C S Goodyear
- University Department of Neurology, Southern General Hospital, Glasgow G51 4TF, Scotland
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45
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Goodyear CS, O'Hanlon GM, Plomp JJ, Wagner ER, Morrison I, Veitch J, Cochrane L, Bullens RW, Molenaar PC, Conner J, Willison HJ. Monoclonal antibodies raised against Guillain-Barré syndrome-associated Campylobacter jejuni lipopolysaccharides react with neuronal gangliosides and paralyze muscle-nerve preparations. J Clin Invest 1999; 104:697-708. [PMID: 10491405 PMCID: PMC408431 DOI: 10.1172/jci6837] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Guillain-Barré syndrome and its variant, Miller-Fisher syndrome, are acute, postinfectious, autoimmune neuropathies that frequently follow Campylobacter jejuni enteritis. The pathogenesis is believed to involve molecular mimicry between sialylated epitopes on C. jejuni LPSs and neural gangliosides. More than 90% of Miller-Fisher syndrome cases have serum anti-GQ1b and anti-GT1a ganglioside antibodies that may also react with other disialylated gangliosides including GD3 and GD1b. Structural studies on LPS from neuropathy-associated C. jejuni strains have revealed GT1a-like and GD3-like core oligosaccharides. To determine whether this structural mimicry results in pathogenic autoantibodies, we immunized mice with GT1a/GD3-like C. jejuni LPS and then cloned mAb's that reacted with both the immunizing LPS and GQ1b/GT1a/GD3 gangliosides. Immunohistology demonstrated antibody binding to ganglioside-rich sites including motor nerve terminals. In ex vivo electrophysiological studies of nerve terminal function, application of antibodies either ex vivo or in vivo via passive immunization induced massive quantal release of acetylcholine, followed by neurotransmission block. This effect was complement-dependent and associated with extensive deposits of IgM and C3c at nerve terminals. These data provide strong support for the molecular mimicry hypothesis as a mechanism for the induction of cross-reactive pathogenic anti-ganglioside/LPS antibodies in postinfectious neuropathies.
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Affiliation(s)
- C S Goodyear
- University Department of Neurology, Southern General Hospital, Glasgow G51 4TF, Scotland
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46
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Van Kempen GT, Trip SA, Molenaar PC. Acetylcholinesterase activity of skeletal muscle in a non-immunogenic model for myasthenia gravis in rats. J Neural Transm (Vienna) 1999; 106:423-31. [PMID: 10443548 DOI: 10.1007/s007020050169] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Myasthenia gravis is caused by an autoimmune attack to acetylcholine receptors of skeletal muscle. Acetylcholine release from motor nerve terminals is upregulated in patients with myasthenia gravis and also in rat "myasthenic" models, dependent on the reduction of the number of acetylcholine receptors. This study addresses the question as to whether at "myasthenic" endplates there are changes in the activity of acetylcholinesterase. To this end we studied acetylcholinesterase activity in junctional and extrajunctional regions of dilator naris, extensor digitorum longus, and hemidiaphragm muscles from rats with alpha-bungarotoxin-induced myasthenia gravis. In all studied muscles from "myasthenic" rats there was no significant change of junctional acetylcholinesterase activity. In contrast, in dilator naris and extensor digitorum longus muscles, there was a 60% and 30% increase of extrajunctional acetylcholinesterase activity. There was no significant change in the extrajunctional activity in hemidiaphragm muscles. Velocity sedimentation analysis revealed that the increase in extrajunctional activity in extensor digitorum longus muscles could be attributed to an increase of the activity of the G4 form of acetylcholinesterase. Treatment of rats with 6.4 microgh(-1) neostigmine bromide for 29 days had no influence on junctional and extrajunctional acetylcholinesterase activity of extensor digitorum longus muscles from rats with alpha-bungarotoxin-induced myasthenia gravis.
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Affiliation(s)
- G T Van Kempen
- Department of Physiology, Leiden University Medical Center, The Netherlands
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Molenaar PC, Raijmakers ME. Additional aspects of third source variation for the genetic analysis of human development and behaviour: a commentary on Eaves et al. Twin Res 1999; 2:49-52. [PMID: 10392803 DOI: 10.1375/136905299320566112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- P C Molenaar
- Faculty of Psychology, University of Amsterdam, The Netherlands.
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Plomp JJ, Molenaar PC, O'Hanlon GM, Jacobs BC, Veitch J, Daha MR, van Doorn PA, van der Meché FG, Vincent A, Morgan BP, Willison HJ. Miller Fisher anti-GQ1b antibodies: alpha-latrotoxin-like effects on motor end plates. Ann Neurol 1999; 45:189-99. [PMID: 9989621 DOI: 10.1002/1531-8249(199902)45:2<189::aid-ana9>3.0.co;2-t] [Citation(s) in RCA: 151] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
In the Miller Fisher syndrome (MFS) variant of the Guillain-Barré syndrome, weakness is restricted to extraocular muscles and occasionally other craniobulbar muscles. Most MFS patients have serum antibodies against ganglioside type GQ1b of which the pathophysiological relevance is unclear. We examined the in vitro effects of MFS sera, MFS IgG, and a human monoclonal anti-GQ1b IgM antibody on mouse neuromuscular junctions (NMJs). It was found that anti-GQ1b antibodies bind at NMJs where they induce massive quantal release of acetylcholine from nerve terminals and eventually block neuromuscular transmission. This effect closely resembled the effect of the paralytic neurotoxin alpha-latrotoxin at the mouse NMJs, implying possible involvement of alpha-latrotoxin receptors or associated downstream pathways. By using complement-deficient sera, the effect of anti-GQ1b antibodies on NMJs was shown to be entirely dependent on activation of complement components. However, neither classical pathway activation nor the formation of membrane attack complex was required, indicating the effects could be due to involvement of the alternative pathway and intermediate complement cascade products. Our findings strongly suggest that anti-GQ1b antibodies in conjunction with activated complement components are the principal pathophysiological mediators of motor symptoms in MFS and that the NMJ is an important site of their action.
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Affiliation(s)
- J J Plomp
- Department of Neurology, Leiden University Medical Centre, The Netherlands
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49
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Abstract
EEG coherence measures the covariation in electrical brain activity between two locations on the scalp and is used to study connectivity between cortical regions. The aim of this study was to determine the heritability of EEG coherence. Coherence was measured in a group of 213 16-yr-old twin pairs. By including male and female twin pairs in the sample, sex differences in genetic architecture were systematically examined. The EEG was obtained during quiet supine resting. Coherence was estimated for short and long distance combinations of electrode pairs along the anterior-posterior axis within a hemisphere for four frequency bands (delta, theta, alpha and beta). Averaged over all electrode combinations about 60% of the variance was explained by genetic factors for coherence in the theta, alpha and beta bands. For the delta band, the heritability was somewhat lower. No systematic sex differences in genetic architecture were found. All environmental influences were nonshared, i.e., unique factors including measurement error. Environmental factors shared by twin siblings did not influence variation in EEG coherence. These results suggest that individual differences in coherence form a potential candidate for (molecular) genetic studies on brain function.
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Wintzen AR, Plomp JJ, Molenaar PC, van Dijk JG, van Kempen GT, Vos RM, Wokke JH, Vincent A. Acquired slow-channel syndrome: a form of myasthenia gravis with prolonged open time of the acetylcholine receptor channel. Ann Neurol 1998; 44:657-64. [PMID: 9778265 DOI: 10.1002/ana.410440412] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A 32-year-old female presented with a 2-year history of fluctuating generalized weakness including extraocular, bulbar, and limb muscles, suggesting myasthenia gravis, but with poor response to pyridostigmine and unusual electromyographic findings. After rest, power increased on repeated maximal contractions, followed by progressive weakness. There were decremental responses at low-frequency stimulation, but incremental responses at high frequencies, and single stimuli evoked repetitive compound muscle action potentials. Plasmapheresis was ineffective. In a conventional assay, antibodies against acetylcholine receptors (AChRs) were borderline. However, in an assay using cells expressing mainly adult-type human AChRs, the patient's serum was positive. Thymectomy revealed a hyperplastic thymus. An intercostal muscle specimen revealed small miniature end-plate potentials, 0.22+/-0.02 mV instead of 0.56+/-0.05 mV in controls. The number of 125I-alpha-bungarotoxin binding sites was normal. The decay time constant of end-plate potentials was increased from 5.3+/-0.6 msec in controls to 23+/-3.6 msec in the patient. Ultrastructurally, there was no destruction of the end plate. Transfer of the patient's plasma to mice in vivo produced similar physiological changes in their diaphragms. We conclude that the patient has an immune-mediated disorder, in which an antibody specific to the adult form of the AChRs alters the channel properties, reducing total current and slowing the closure. We propose the name "acquired slow-channel syndrome" for this variant of myasthenia gravis.
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Affiliation(s)
- A R Wintzen
- Department of Neurology and Clinical Neurophysiology, Leiden University Medical Centre, The Netherlands
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