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Flace P, Galletta D, Bizzoca A, Gennarini G, Livrea P. A candidate projective neuron type of the cerebellar cortex: the synarmotic neuron. Eur J Histochem 2024; 68:3954. [PMID: 38766720 PMCID: PMC11148694 DOI: 10.4081/ejh.2024.3954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 04/20/2024] [Indexed: 05/22/2024] Open
Abstract
Previous studies on the granular layer of the cerebellar cortex have revealed a wide distribution of different subpopulations of less-known large neuron types, called "non-traditional large neurons", which are distributed in three different zones of the granular layer. These neuron types are mainly involved in the formation of intrinsiccircuits inside the cerebellar cortex. A subpopulation of these neuron types is represented by the synarmotic neuron, which could play a projective role within the cerebellar circuitry. The synarmotic neuron cell body map within the internal zone of the granular layer or in the subjacent white substance. Furthermore, the axon crosses the granular layer and runs in the subcortical white substance, to reenter in an adjacent granular layer, associating two cortico-cerebellar regions of the same folium or of different folia, or could project to the intrinsic cerebellar nuclei. Therefore, along with the Purkinje neuron, the traditional projective neuron type of the cerebellar cortex, the synarmotic neuron is candidate to represent the second projective neuron type of the cerebellar cortex. Studies of chemical neuroanatomy evidenced a predominant inhibitory GABAergic nature of the synarmotic neuron, suggesting that it may mediate an inhibitory GABAergic output of cerebellar cortex within cortico-cortical interconnections or in projections towards intrinsic cerebellar nuclei. On this basis, the present minireview mainly focuses on the morphofunctional and neurochemical data of the synarmotic neuron, and explores its potential involvement in some forms of cerebellar ataxias.
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Affiliation(s)
- Paolo Flace
- Medical School, University of Bari Aldo Moro, Bari.
| | - Diana Galletta
- Unit of Psychiatry and Psychology, Federico II University Hospital, Naples.
| | - Antonella Bizzoca
- Department of Translational Biomedicine and Neuroscience "DiBraiN", University of Bari Aldo Moro, Bari.
| | - Gianfranco Gennarini
- Department of Translational Biomedicine and Neuroscience "DiBraiN", University of Bari Aldo Moro, Bari.
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2
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Masciocchi S, Businaro P, Scaranzin S, Morandi C, Franciotta D, Gastaldi M. General features, pathogenesis, and laboratory diagnostics of autoimmune encephalitis. Crit Rev Clin Lab Sci 2024; 61:45-69. [PMID: 37777038 DOI: 10.1080/10408363.2023.2247482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 08/09/2023] [Indexed: 10/02/2023]
Abstract
Autoimmune encephalitis (AE) is a group of inflammatory conditions that can associate with the presence of antibodies directed to neuronal intracellular, or cell surface antigens. These disorders are increasingly recognized as an important differential diagnosis of infectious encephalitis and of other common neuropsychiatric conditions. Autoantibody diagnostics plays a pivotal role for accurate diagnosis of AE, which is of utmost importance for the prompt recognition and early treatment. Several AE subgroups can be identified, either according to the prominent clinical phenotype, presence of a concomitant tumor, or type of neuronal autoantibody, and recent diagnostic criteria have provided important insights into AE classification. Antibodies to neuronal intracellular antigens typically associate with paraneoplastic neurological syndromes and poor prognosis, whereas antibodies to synaptic/neuronal cell surface antigens characterize many AE subtypes that associate with tumors less frequently, and that are often immunotherapy-responsive. In addition to the general features of AE, we review current knowledge on the pathogenic mechanisms underlying these disorders, focusing mainly on the potential role of neuronal antibodies in the most frequent conditions, and highlight current theories and controversies. Then, we dissect the crucial aspects of the laboratory diagnostics of neuronal antibodies, which represents an actual challenge for both pathologists and neurologists. Indeed, this diagnostics entails technical difficulties, along with particularly interesting novel features and pitfalls. The novelties especially apply to the wide range of assays used, including specific tissue-based and cell-based assays. These assays can be developed in-house, usually in specialized laboratories, or are commercially available. They are widely used in clinical immunology and in clinical chemistry laboratories, with relevant differences in analytic performance. Indeed, several data indicate that in-house assays could perform better than commercial kits, notwithstanding that the former are based on non-standardized protocols. Moreover, they need expertise and laboratory facilities usually unavailable in clinical chemistry laboratories. Together with the data of the literature, we critically evaluate the analytical performance of the in-house vs commercial kit-based approach. Finally, we propose an algorithm aimed at integrating the present strategies of the laboratory diagnostics in AE for the best clinical management of patients with these disorders.
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Affiliation(s)
- Stefano Masciocchi
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, Università degli Studi di Pavia, Pavia, Italy
| | - Pietro Businaro
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioral Sciences, Università degli Studi di Pavia, Pavia, Italy
| | - Silvia Scaranzin
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
| | - Chiara Morandi
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
| | - Diego Franciotta
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
| | - Matteo Gastaldi
- Neuroimmunology Research Section, IRCCS Mondino Foundation, Pavia, Italy
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Ryding M, Mikkelsen AW, Nissen MS, Nilsson AC, Blaabjerg M. Pathophysiological Effects of Autoantibodies in Autoimmune Encephalitides. Cells 2023; 13:15. [PMID: 38201219 PMCID: PMC10778077 DOI: 10.3390/cells13010015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 12/15/2023] [Accepted: 12/18/2023] [Indexed: 01/12/2024] Open
Abstract
The heterogeneity of autoantibody targets in autoimmune encephalitides presents a challenge for understanding cellular and humoral pathophysiology, and the development of new treatment strategies. Thus, current treatment aims at autoantibody removal and immunosuppression, and is primarily based on data generated from other autoimmune neurological diseases and expert consensus. There are many subtypes of autoimmune encephalitides, which now entails both diseases with autoantibodies targeting extracellular antigens and classical paraneoplastic syndromes with autoantibodies targeting intracellular antigens. Here, we review the current knowledge of molecular and cellular effects of autoantibodies associated with autoimmune encephalitis, and evaluate the evidence behind the proposed pathophysiological mechanisms of autoantibodies in autoimmune encephalitis.
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Affiliation(s)
- Matias Ryding
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
| | - Anne With Mikkelsen
- Department of Clinical Immunology, Odense University Hospital, 5000 Odense, Denmark;
| | | | - Anna Christine Nilsson
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Department of Clinical Immunology, Odense University Hospital, 5000 Odense, Denmark;
| | - Morten Blaabjerg
- Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark;
- Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, 5000 Odense, Denmark
- Department of Neurology, Odense University Hospital, 5000 Odense, Denmark;
- Brain Research—Inter Disciplinary Guided Excellence (BRIDGE), 5000 Odense, Denmark
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4
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Peng Y, Yang H, Xue YH, Chen Q, Jin H, Liu S, Yao SY, Du MQ. An update on malignant tumor-related stiff person syndrome spectrum disorders: clinical mechanism, treatment, and outcomes. Front Neurol 2023; 14:1209302. [PMID: 37859648 PMCID: PMC10582361 DOI: 10.3389/fneur.2023.1209302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Accepted: 09/01/2023] [Indexed: 10/21/2023] Open
Abstract
Stiff person syndrome (SPS) is a rare central nervous system disorder associated with malignancies. In this review, we retrieved information from PubMed, up until August 2023, using various search terms and their combinations, including SPS, stiff person syndrome spectrum disorders (SPSSDs), paraneoplastic, cancer, and malignant tumor. Data from peer-reviewed journals printed in English were organized to explain the possible relationships between different carcinomas and SPSSD subtypes, as well as related autoantigens. From literature searching, it was revealed that breast cancer was the most prevalent carcinoma linked to SPSSDs, followed by lung cancer and lymphoma. Furthermore, classic SPS was the most common SPSSD subtype, followed by stiff limb syndrome and progressive encephalomyelitis with rigidity and myoclonus. GAD65 was the most common autoantigen in patients with cancer and SPSSDs, followed by amphiphysin and GlyR. Patients with cancer subtypes might have multiple SPSSD subtypes, and conversely, patients with SPSSD subtypes might have multiple carcinoma subtypes. The first aim of this review was to highlight the complex nature of the relationships among cancers, autoantigens, and SPSSDs as new information in this field continues to be generated globally. The adoption of an open-minded approach to updating information on new cancer subtypes, autoantigens, and SPSSDs is recommended to renew our database. The second aim of this review was to discuss SPS animal models, which will help us to understand the mechanisms underlying the pathogenesis of SPS. In future, elucidating the relationship among cancers, autoantigens, and SPSSDs is critical for the early prediction of cancer and discovery of new therapeutic modalities.
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Affiliation(s)
- Yong Peng
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Huan Yang
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Ya-hui Xue
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Quan Chen
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Hong Jin
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Shu Liu
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Shun-yu Yao
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
| | - Miao-qiao Du
- Department of Neurology, Affiliated First Hospital of Hunan Traditional Chinese Medical College, Zhuzhou, Hunan, China
- The Third Affiliated Hospital of Hunan University of Chinese Medicine, Zhuzhou, Hunan, China
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Koevoet D, Deschamps PKH, Kenemans JL. Catecholaminergic and cholinergic neuromodulation in autism spectrum disorder: A comparison to attention-deficit hyperactivity disorder. Front Neurosci 2023; 16:1078586. [PMID: 36685234 PMCID: PMC9853424 DOI: 10.3389/fnins.2022.1078586] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Accepted: 12/15/2022] [Indexed: 01/09/2023] Open
Abstract
Autism spectrum disorder (ASD) is a heterogeneous neurodevelopmental disorder characterized by social impairments and restricted, repetitive behaviors. Treatment of ASD is notoriously difficult and might benefit from identification of underlying mechanisms that overlap with those disturbed in other developmental disorders, for which treatment options are more obvious. One example of the latter is attention-deficit hyperactivity disorder (ADHD), given the efficacy of especially stimulants in treatment of ADHD. Deficiencies in catecholaminergic systems [dopamine (DA), norepinephrine (NE)] in ADHD are obvious targets for stimulant treatment. Recent findings suggest that dysfunction in catecholaminergic systems may also be a factor in at least a subgroup of ASD. In this review we scrutinize the evidence for catecholaminergic mechanisms underlying ASD symptoms, and also include in this analysis a third classic ascending arousing system, the acetylcholinergic (ACh) network. We complement this with a comprehensive review of DA-, NE-, and ACh-targeted interventions in ASD, and an exploratory search for potential treatment-response predictors (biomarkers) in ASD, genetically or otherwise. Based on this review and analysis we propose that (1) stimulant treatment may be a viable option for an ASD subcategory, possibly defined by genetic subtyping; (2) cerebellar dysfunction is pronounced for a relatively small ADHD subgroup but much more common in ASD and in both cases may point toward NE- or ACh-directed intervention; (3) deficiency of the cortical salience network is sizable in subgroups of both disorders, and biomarkers such as eye blink rate and pupillometric data may predict the efficacy of targeting this underlying deficiency via DA, NE, or ACh in both ASD and ADHD.
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Affiliation(s)
- Damian Koevoet
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands,*Correspondence: Damian Koevoet,
| | - P. K. H. Deschamps
- Department of Psychiatry, University Medical Center Utrecht, Utrecht, Netherlands
| | - J. L. Kenemans
- Experimental Psychology, Helmholtz Institute, Utrecht University, Utrecht, Netherlands
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6
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Mitoma H, Manto M. Advances in the Pathogenesis of Auto-antibody-Induced Cerebellar Synaptopathies. CEREBELLUM (LONDON, ENGLAND) 2023; 22:129-147. [PMID: 35064896 PMCID: PMC9883363 DOI: 10.1007/s12311-021-01359-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 12/12/2021] [Indexed: 02/07/2023]
Abstract
The presence of auto-antibodies that target synaptic machinery proteins was documented recently in immune-mediated cerebellar ataxias. The autoantigens include glutamic acid decarboxylase 65 (GAD65), voltage-gated Ca2+ channel (VGCC), metabotropic glutamate receptor type 1 (mGluR1), and glutamate receptor delta (GluRdelta). GAD65 is involved in the synthesis, packaging, and release of GABA, whereas the other three play important roles in the induction of long-term depression (LTD). Thus, the auto-antibodies toward these synaptic molecules likely impair fundamental synaptic machineries involved in unique functions of the cerebellum, potentially leading to the development of cerebellar ataxias (CAs). This concept has been substantiated recently by a series of physiological studies. Anti-GAD65 antibody (Ab) acts on the terminals of inhibitory neurons that suppress GABA release, whereas anti-VGCC, anti-mGluR1, and anti-GluR Abs impair LTD induction. Notably, the mechanisms that link synaptic dysfunction with the manifestations of CAs can be explained by disruption of the "internal models." The latter can be divided into three levels. First, since chained inhibitory neurons shape the output signals through the mechanism of disinhibition/inhibition, impairments of GABA release and LTD distort the conversion process from the "internal model" to the output signals. Second, these antibodies impair the induction of synaptic plasticity, rebound potentiation, and LTD, on Purkinje cells, resulting in loss of restoration and compensation of the distorted "internal models." Finally, the cross-talk between glutamate and microglia/astrocytes could involve a positive feedback loop that accelerates excitotoxicity. This mini-review summarizes the pathophysiological mechanisms and aims to establish the basis of "auto-antibody-induced cerebellar synaptopathies."
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan
| | - Mario Manto
- Unité des Ataxies Cérébelleuses, Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000 Charleroi, Belgium ,Service des Neurosciences, University of Mons, 7000 Mons, Belgium
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7
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Hampe CS, Mitoma H. A Breakdown of Immune Tolerance in the Cerebellum. Brain Sci 2022; 12:brainsci12030328. [PMID: 35326284 PMCID: PMC8946792 DOI: 10.3390/brainsci12030328] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/22/2022] [Accepted: 02/25/2022] [Indexed: 11/21/2022] Open
Abstract
Cerebellar dysfunction can be associated with ataxia, dysarthria, dysmetria, nystagmus and cognitive deficits. While cerebellar dysfunction can be caused by vascular, traumatic, metabolic, genetic, inflammatory, infectious, and neoplastic events, the cerebellum is also a frequent target of autoimmune attacks. The underlying cause for this vulnerability is unclear, but it may be a result of region-specific differences in blood–brain barrier permeability, the high concentration of neurons in the cerebellum and the presence of autoantigens on Purkinje cells. An autoimmune response targeting the cerebellum—or any structure in the CNS—is typically accompanied by an influx of peripheral immune cells to the brain. Under healthy conditions, the brain is protected from the periphery by the blood–brain barrier, blood–CSF barrier, and blood–leptomeningeal barrier. Entry of immune cells to the brain for immune surveillance occurs only at the blood-CSF barrier and is strictly controlled. A breakdown in the barrier permeability allows peripheral immune cells uncontrolled access to the CNS. Often—particularly in infectious diseases—the autoimmune response develops because of molecular mimicry between the trigger and a host protein. In this review, we discuss the immune surveillance of the CNS in health and disease and also discuss specific examples of autoimmunity affecting the cerebellum.
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Affiliation(s)
- Christiane S. Hampe
- Department of Medicine, University of Washington, Seattle, WA 98195, USA
- Correspondence: ; Tel.: +1-206-554-9181
| | - Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo 160-0023, Japan;
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8
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Mitoma H, Manto M, Hadjivassiliou M. Immune-Mediated Cerebellar Ataxias: Clinical Diagnosis and Treatment Based on Immunological and Physiological Mechanisms. J Mov Disord 2021; 14:10-28. [PMID: 33423437 PMCID: PMC7840241 DOI: 10.14802/jmd.20040] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 09/04/2020] [Indexed: 12/24/2022] Open
Abstract
Since the first description of immune-mediated cerebellar ataxias (IMCAs) by Charcot in 1868, several milestones have been reached in our understanding of this group of neurological disorders. IMCAs have diverse etiologies, such as gluten ataxia, postinfectious cerebellitis, paraneoplastic cerebellar degeneration, opsoclonus myoclonus syndrome, anti-GAD ataxia, and primary autoimmune cerebellar ataxia. The cerebellum, a vulnerable autoimmune target of the nervous system, has remarkable capacities (collectively known as the cerebellar reserve, closely linked to plasticity) to compensate and restore function following various pathological insults. Therefore, good prognosis is expected when immune-mediated therapeutic interventions are delivered during early stages when the cerebellar reserve can be preserved. However, some types of IMCAs show poor responses to immunotherapies, even if such therapies are introduced at an early stage. Thus, further research is needed to enhance our understanding of the autoimmune mechanisms underlying IMCAs, as such research could potentially lead to the development of more effective immunotherapies. We underscore the need to pursue the identification of robust biomarkers.
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan
| | - Mario Manto
- Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, Charleroi, Belgium.,Service des Neurosciences, University of Mons, Mons, Belgium
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Fundamental Mechanisms of Autoantibody-Induced Impairments on Ion Channels and Synapses in Immune-Mediated Cerebellar Ataxias. Int J Mol Sci 2020; 21:ijms21144936. [PMID: 32668612 PMCID: PMC7404345 DOI: 10.3390/ijms21144936] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Revised: 07/07/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022] Open
Abstract
In the last years, different kinds of limbic encephalitis associated with autoantibodies against ion channels and synaptic receptors have been described. Many studies have demonstrated that such autoantibodies induce channel or receptor dysfunction. The same mechanism is discussed in immune-mediated cerebellar ataxias (IMCAs), but the pathogenesis has been less investigated. The aim of the present review is to evaluate what kind of cerebellar ion channels, their related proteins, and the synaptic machinery proteins that are preferably impaired by autoantibodies so as to develop cerebellar ataxias (CAs). The cerebellum predictively coordinates motor and cognitive functions through a continuous update of an internal model. These controls are relayed by cerebellum-specific functions such as precise neuronal discharges with potassium channels, synaptic plasticity through calcium signaling pathways coupled with voltage-gated calcium channels (VGCC) and metabotropic glutamate receptors 1 (mGluR1), a synaptic organization with glutamate receptor delta (GluRδ), and output signal formation through chained GABAergic neurons. Consistently, the association of CAs with anti-potassium channel-related proteins, anti-VGCC, anti-mGluR1, and GluRδ, and anti-glutamate decarboxylase 65 antibodies is observed in IMCAs. Despite ample distributions of AMPA and GABA receptors, however, CAs are rare in conditions with autoantibodies against these receptors. Notably, when the autoantibodies impair synaptic transmission, the autoimmune targets are commonly classified into three categories: release machinery proteins, synaptic adhesion molecules, and receptors. This physiopathological categorization impacts on both our understanding of the pathophysiology and clinical prognosis.
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Graus F, Saiz A, Dalmau J. GAD antibodies in neurological disorders — insights and challenges. Nat Rev Neurol 2020; 16:353-365. [DOI: 10.1038/s41582-020-0359-x] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/03/2020] [Indexed: 01/07/2023]
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Dade M, Berzero G, Izquierdo C, Giry M, Benazra M, Delattre JY, Psimaras D, Alentorn A. Neurological Syndromes Associated with Anti-GAD Antibodies. Int J Mol Sci 2020; 21:E3701. [PMID: 32456344 PMCID: PMC7279468 DOI: 10.3390/ijms21103701] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/19/2020] [Accepted: 05/21/2020] [Indexed: 12/11/2022] Open
Abstract
Glutamic acid decarboxylase (GAD) is an intracellular enzyme whose physiologic function is the decarboxylation of glutamate to gamma-aminobutyric acid (GABA), the main inhibitory neurotransmitter within the central nervous system. GAD antibodies (Ab) have been associated with multiple neurological syndromes, including stiff-person syndrome, cerebellar ataxia, and limbic encephalitis, which are all considered to result from reduced GABAergic transmission. The pathogenic role of GAD Ab is still debated, and some evidence suggests that GAD autoimmunity might primarily be cell-mediated. Diagnosis relies on the detection of high titers of GAD Ab in serum and/or in the detection of GAD Ab in the cerebrospinal fluid. Due to the relative rarity of these syndromes, treatment schemes and predictors of response are poorly defined, highlighting the unmet need for multicentric prospective trials in this population. Here, we reviewed the main clinical characteristics of neurological syndromes associated with GAD Ab, focusing on pathophysiologic mechanisms.
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Affiliation(s)
- Maëlle Dade
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Neurologie 2-Mazarin, 75013 Paris, France; (M.D.); (G.B.); (J.-Y.D.); (D.P.)
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
| | - Giulia Berzero
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Neurologie 2-Mazarin, 75013 Paris, France; (M.D.); (G.B.); (J.-Y.D.); (D.P.)
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
- Neuroncology Unit, IRCCS Mondino Foundation, 27100 Pavia, Italy
| | - Cristina Izquierdo
- Department of Neuroscience, Hospital Universitari Germans Trias i Pujol, Universitat Autònoma de Barcelona, 08916 Badalona, Spain;
| | - Marine Giry
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
| | - Marion Benazra
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
| | - Jean-Yves Delattre
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Neurologie 2-Mazarin, 75013 Paris, France; (M.D.); (G.B.); (J.-Y.D.); (D.P.)
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
| | - Dimitri Psimaras
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Neurologie 2-Mazarin, 75013 Paris, France; (M.D.); (G.B.); (J.-Y.D.); (D.P.)
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
| | - Agusti Alentorn
- AP-HP, Groupe Hospitalier Pitié-Salpêtrière, Service de Neurologie 2-Mazarin, 75013 Paris, France; (M.D.); (G.B.); (J.-Y.D.); (D.P.)
- Sorbonne Université, Inserm, CNRS, UMR S 1127, Institut du Cerveau et de la Moelle épinière, ICM, 75013 Paris, France; (M.G.); (M.B.)
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Frerker B, Rohde M, Müller S, Bien CG, Köhling R, Kirschstein T. Distinct Effects of Stereotactically Injected Human Cerebrospinal Fluid Containing Glutamic Acid Decarboxylase Antibodies into the Hippocampus of Rats on the Development of Spontaneous Epileptic Activity. Brain Sci 2020; 10:brainsci10020123. [PMID: 32098388 PMCID: PMC7071523 DOI: 10.3390/brainsci10020123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 12/16/2022] Open
Abstract
Background: The conversion of glutamic acid into γ-aminobutyric acid (GABA) is catalyzed by the glutamic acid decarboxylase (GAD). Antibodies against this enzyme have been described in neurological disorders, but the pathophysiological role of these antibodies is still poorly understood. We hypothesized that anti-GAD autoantibodies could diminish the GABA content in the slice and facilitate epileptic activity. Methods: Cerebrospinal fluids (CSF) from two patients containing anti-GAD (A and B) were injected into the rat hippocampus in vivo. Hippocampal slices were prepared for electrophysiological field potential recordings in order to record recurrent epileptic discharges (REDs) in the CA1 region induced by the removal of Mg2+ and/or by adding gabazine. As control groups, we injected an anti-GAD-negative human CSF or saline solution, and we used non-operated naive animals. Results: RED frequencies were significantly higher in the Mg2+-free solution than in the gabazine-containing solution. The average frequency of REDs in the last 10 min and the average duration of REDs in the last 5 min did not show significant differences between the anti-GAD-B-treated and the control slices, but in the Mg2+-free solution, anti-GAD-A had significantly higher epileptic activity than anti-GAD-B. Conclusions: These results indicate that anti-GAD has distinct effects on the development of spontaneous epileptic activity.
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Affiliation(s)
- Bernd Frerker
- Oscar Langendorff Institute of Physiology, University of Rostock, 18057 Rostock, Germany
- Department of Irradiation Therapy, University Hospital of Rostock, 18059 Rostock, Germany
- Correspondence: ; Tel.: +49(0)-381-494-9001; Fax: +49(0)-381-494-9002
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock, 18057 Rostock, Germany
| | - Steffen Müller
- Oscar Langendorff Institute of Physiology, University of Rostock, 18057 Rostock, Germany
| | | | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock, 18057 Rostock, Germany
- Center of Transdisciplinary Neurosciences Rostock, University of Rostock, 18147 Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock, 18057 Rostock, Germany
- Center of Transdisciplinary Neurosciences Rostock, University of Rostock, 18147 Rostock, Germany
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13
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Manto M, Mitoma H, Hampe CS. Anti-GAD Antibodies and the Cerebellum: Where Do We Stand? THE CEREBELLUM 2019; 18:153-156. [PMID: 30343467 PMCID: PMC6443918 DOI: 10.1007/s12311-018-0986-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Anti-GAD65 antibodies (anti-GAD65 Abs) are associated with cerebellar ataxia (CA). The significance of anti-GAD65 Abs has been a focus of debates. Since GAD65 is intracellularly located and associated with type 1 diabetes mellitus and different clinical neurological phenotypes such as CA, stiff-person syndrome, and epilepsy, some researchers have argued that anti-GAD65 Abs have no pathogenic roles. On the other hand, recent physiological studies in vitro and in vivo have elucidated that binding of GAD65 by anti-GAD65 Abs elicits loss of GAD65 functions pertaining GABA release with an epitope dependence, leading to the development of CA. Internalization of autoantibodies has been also clarified. These studies provide substantial evidence of the pathogenesis of anti-GAD65 Abs in CA. We also discuss methodological problems in the identification of anti-GAD65 Abs.
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Affiliation(s)
- Mario Manto
- Service de Neurologie, Médiathèque Jean Jacquy, CHU-Charleroi, 6000, Charleroi, Belgium.,Service des Neurosciences, University of Mons, 7000, Mons, Belgium
| | - Hiroshi Mitoma
- Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan.
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14
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Kakei S, Ishikawa T, Lee J, Honda T, Hoffman DS. Physiological and Morphological Principles Underpinning Recruitment of the Cerebellar Reserve. CNS & NEUROLOGICAL DISORDERS-DRUG TARGETS 2019; 17:184-192. [PMID: 29546837 PMCID: PMC6142411 DOI: 10.2174/1871527317666180315164429] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Revised: 12/25/2017] [Accepted: 12/27/2017] [Indexed: 12/05/2022]
Abstract
Background: In order to optimize outcomes of novel therapies for cerebellar ataxias (CAs), it is desirable to start these therapies while declined functions are restorable: i.e. while the so-called cere-bellar reserve remains. Objective: In this mini-review, we tried to define and discuss the cerebellar reserve from physiological and morphological points of view. Method: The cerebellar neuron circuitry is designed to generate spatiotemporally organized outputs, re-gardless of the region. Therefore, the cerebellar reserve may be defined as a mechanism to restore its proper input-output organization of the cerebellar neuron circuitry, when it is damaged. Then, the follow-ing four components are essential for recruitment of the cerebellar reserve: operational local neuron cir-cuitry; proper combination of mossy fiber inputs to be integrated; climbing fiber inputs to instruct favor-able reorganization of the integration; deep cerebellar nuclei to generate reorganized outputs. Results: We discussed three topics related to these resources, 1) principles of generating organized cere-bellar outputs, 2) redundant mossy fiber inputs to the cerebellum, 3) plasticity of the cerebellar neuron circuitry. Conclusion: To make most of the cerebellar reserve, it is desirable to start any intervention as early as possible when the cerebellar cell loss is minimal or even negligible. Therefore, an ideal future therapy for degenerative cerebellar diseases should start before consuming the cerebellar reserve at all. In the meantime, our real challenge is to establish a reliable method to identify the decrease in the cerebellar re-serve as early as possible.
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Affiliation(s)
- Shinji Kakei
- Movement Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takahiro Ishikawa
- Movement Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Jongho Lee
- Movement Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Takeru Honda
- Movement Disorders Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Donna S Hoffman
- Department of Neurobiology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States.,Center for the Neural Basis of Cognition, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, United States
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15
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Mitoma H, Manto M, Hampe CS. Immune-mediated Cerebellar Ataxias: Practical Guidelines and Therapeutic Challenges. Curr Neuropharmacol 2019; 17:33-58. [PMID: 30221603 PMCID: PMC6341499 DOI: 10.2174/1570159x16666180917105033] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2018] [Revised: 07/06/2018] [Accepted: 09/03/2018] [Indexed: 12/11/2022] Open
Abstract
Immune-mediated cerebellar ataxias (IMCAs), a clinical entity reported for the first time in the 1980s, include gluten ataxia (GA), paraneoplastic cerebellar degenerations (PCDs), antiglutamate decarboxylase 65 (GAD) antibody-associated cerebellar ataxia, post-infectious cerebellitis, and opsoclonus myoclonus syndrome (OMS). These IMCAs share common features with regard to therapeutic approaches. When certain factors trigger immune processes, elimination of the antigen( s) becomes a priority: e.g., gluten-free diet in GA and surgical excision of the primary tumor in PCDs. Furthermore, various immunotherapeutic modalities (e.g., steroids, immunoglobulins, plasmapheresis, immunosuppressants, rituximab) should be considered alone or in combination to prevent the progression of the IMCAs. There is no evidence of significant differences in terms of response and prognosis among the various types of immunotherapies. Treatment introduced at an early stage, when CAs or cerebellar atrophy is mild, is associated with better prognosis. Preservation of the "cerebellar reserve" is necessary for the improvement of CAs and resilience of the cerebellar networks. In this regard, we emphasize the therapeutic principle of "Time is Cerebellum" in IMCAs.
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Affiliation(s)
- Hiroshi Mitoma
- Address correspondence to this author at the Medical Education Promotion Center, Tokyo Medical University, Tokyo, Japan;, E-mail:
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16
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Nakamura Y, Nakajima H, Hosokawa T, Yamane K, Ishida S, Kimura F. Acute Cerebellar Ataxia Associated with Anti-glutamic Acid Decarboxylase Antibodies Mimicking Miller Fisher Syndrome. Intern Med 2018; 57:269-271. [PMID: 29093402 PMCID: PMC5820049 DOI: 10.2169/internalmedicine.9190-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We herein report the case of a 53-year-old man with cerebellar ataxia with anti-glutamic acid decarboxylase antibody (GAD-Ab) who mimicked Miller Fisher syndrome (MFS). He developed ophthalmoplegia, diplopia, and gait ataxia for one week. The serum and cerebrospinal fluid GAD-Ab titers were greatly increased, and the GAD-Ab index suggesting intrathecal antibody synthesis was elevated, while GQ1b-Ab was negative. After steroid pulse therapy and following prednisolone, his symptoms dramatically improved over the course of 11 months with the simultaneous decline of GAD-Ab titers. This case indicates that cerebellar ataxia with GAD-Ab can present with acute neurological findings mimicking MFS, and that steroid therapy has an excellent therapeutic effect.
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Affiliation(s)
- Yoshitsugu Nakamura
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
| | - Hideto Nakajima
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
| | - Takafumi Hosokawa
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
| | - Kazushi Yamane
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
| | - Shimon Ishida
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
| | - Fumiharu Kimura
- Division of Neurology, Department of Internal Medicine IV, Osaka Medical College, Japan
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17
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Mitoma H, Manto M, Hampe CS. Immune-mediated cerebellar ataxias: from bench to bedside. CEREBELLUM & ATAXIAS 2017; 4:16. [PMID: 28944066 PMCID: PMC5609024 DOI: 10.1186/s40673-017-0073-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2017] [Accepted: 09/07/2017] [Indexed: 02/08/2023]
Abstract
The cerebellum is a vulnerable target of autoimmunity in the CNS. The category of immune-mediated cerebellar ataxias (IMCAs) was recently established, and includes in particular paraneoplastic cerebellar degenerations (PCDs), gluten ataxia (GA) and anti-GAD65 antibody (Ab) associated-CA, all characterized by the presence of autoantibodies. The significance of onconeuronal autoantibodies remains uncertain in some cases. The pathogenic role of anti-GAD65Ab has been established both in vitro and in vivo, but a consensus has not been reached yet. Recent studies of anti-GAD65 Ab-associated CA have clarified that (1) autoantibodies are generally polyclonal and elicit pathogenic effects related to epitope specificity, and (2) the clinical course can be divided into two phases: a phase of functional disorder followed by cell death. These features provide the rationale for prompt diagnosis and therapeutic strategies. The concept “Time is brain” has been completely underestimated in the field of immune ataxias. We now put forward the concept “Time is cerebellum” to underline the importance of very early therapeutic strategies in order to prevent or stop the loss of neurons and synapses. The diagnosis of IMCAs should depend not only on Ab testing, but rather on a rapid and comprehensive assessment of the clinical/immune profile. Treatment should be applied during the period of preserved cerebellar reserve, and should encompass early removal of the conditions (such as remote primary tumors) or diseases that trigger the autoimmunity, followed by the combinations of various immunotherapies.
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Affiliation(s)
- Hiroshi Mitoma
- Tokyo Medical University, Medical Education Promotion Center, 6-7-1 Nishi-Shinjyuku, Shinjyuku-ku, Tokyo, 160-0023 Japan
| | - Mario Manto
- Unité d'Etude du Mouvement (UEM), FNRS, ULB-Erasme, 1070 Bruxelles, Belgium.,Service des Neurosciences, University of Mons, 7000 Mons, Belgium
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18
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Pathogenic Roles of Glutamic Acid Decarboxylase 65 Autoantibodies in Cerebellar Ataxias. J Immunol Res 2017; 2017:2913297. [PMID: 28386570 PMCID: PMC5366212 DOI: 10.1155/2017/2913297] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 12/05/2016] [Accepted: 01/10/2017] [Indexed: 12/12/2022] Open
Abstract
Reports suggesting a pathogenic role of autoantibodies directed against glutamic acid decarboxylase 65 (GAD65Abs) in cerebellar ataxias (CAs) are reviewed, and debatable issues such as internalization of antibodies by neurons and roles of epitopes are discussed. GAD65 is one of two enzymes that catalyze the conversion of glutamate to the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). A pathogenic role of GAD65Ab in CAs is suggested by in vivo and in vitro studies. (1) Intracerebellar administration of cerebrospinal fluid (CSF) immunoglobulins (IgGs) obtained from GAD65Ab-positive CA patients impairs cerebellar modulation of motor control in rats. (2) CSF IgGs act on terminals of GABAergic neurons and decrease the release of GABA in cerebellar slices from rats and mice. (3) Absorption of GAD65Ab by recombinant GAD65 diminishes the above effects, and monoclonal human GAD65Ab (b78) mimic the effects of CSF IgGs in vivo and in vitro. Studies using GAD65-KO mice confirm that the target molecule is GAD65. (4) Notably, the effects of GAD65Ab depend on the epitope specificity of the monoclonal GAD65Ab. Taken together, these results indicate that epitope-specific GAD65Ab-induced impairment of GABA release is involved in the pathogenesis of GAD65Ab-positive CA and support the early detection of GAD65Ab-associated CA to initiate immunotherapy before irreversible neuronal death in the cerebellum.
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19
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Hackert JK, Müller L, Rohde M, Bien CG, Köhling R, Kirschstein T. Anti-GAD65 Containing Cerebrospinal Fluid Does not Alter GABAergic Transmission. Front Cell Neurosci 2016; 10:130. [PMID: 27242441 PMCID: PMC4870265 DOI: 10.3389/fncel.2016.00130] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2015] [Accepted: 04/29/2016] [Indexed: 01/17/2023] Open
Abstract
Glutamic acid decarboxylase of 65 kDa (GAD65) antibodies have been reported in a variety of neurological disorders such as stiff-person syndrome (SPS), sporadic ataxia and some cases of epilepsy. Since the target is believed to be the cytoplasmic enzyme GAD65, the key enzyme of γ-aminobutyric acid (GABA) synthesis, the pathophysiological role of these antibodies is poorly understood. Here, we stereotactically injected human cerebrospinal fluid (CSF) containing GAD65-antibodies into the hippocampus of rats in vivo and then prepared hippocampal slices 1-2 days after post-operative recovery. We characterized both evoked and spontaneous GABAergic transmission in vitro using sharp microelectrode and patch-clamp recordings in CA1 neurons. Intracellular recordings with sharp microelectrodes from CA1 neurons showed that evoked GABAAR- or GABABR-mediated inhibitory postsynaptic potentials (IPSP) remained unaltered in anti-GAD65 tissue. These results were confirmed with patch-clamp recordings showing no difference in evoked gabazine-sensitive inhibitory postsynaptic currents (IPSCs). In addition, spontaneous IPSCs also showed no difference between anti-GAD65 tissue and controls with respect to the mean frequency, the mean amplitude and the sIPSC distribution. In conclusion, stereotactic injection of GAD65-antibodies into the hippocampus leaves evoked and spontaneous GABAergic synaptic transmission intact. Hence, dysfunction of the inhibitory GABAergic system does not appear to be the major mechanism of epileptogenicity in this disease.
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Affiliation(s)
- Jana K Hackert
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Lorenz Müller
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Marco Rohde
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | | | - Rüdiger Köhling
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
| | - Timo Kirschstein
- Oscar Langendorff Institute of Physiology, University of Rostock Rostock, Germany
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20
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Mitoma H, Adhikari K, Aeschlimann D, Chattopadhyay P, Hadjivassiliou M, Hampe CS, Honnorat J, Joubert B, Kakei S, Lee J, Manto M, Matsunaga A, Mizusawa H, Nanri K, Shanmugarajah P, Yoneda M, Yuki N. Consensus Paper: Neuroimmune Mechanisms of Cerebellar Ataxias. CEREBELLUM (LONDON, ENGLAND) 2016; 15:213-32. [PMID: 25823827 PMCID: PMC4591117 DOI: 10.1007/s12311-015-0664-x] [Citation(s) in RCA: 103] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In the last few years, a lot of publications suggested that disabling cerebellar ataxias may develop through immune-mediated mechanisms. In this consensus paper, we discuss the clinical features of the main described immune-mediated cerebellar ataxias and address their presumed pathogenesis. Immune-mediated cerebellar ataxias include cerebellar ataxia associated with anti-GAD antibodies, the cerebellar type of Hashimoto's encephalopathy, primary autoimmune cerebellar ataxia, gluten ataxia, Miller Fisher syndrome, ataxia associated with systemic lupus erythematosus, and paraneoplastic cerebellar degeneration. Humoral mechanisms, cell-mediated immunity, inflammation, and vascular injuries contribute to the cerebellar deficits in immune-mediated cerebellar ataxias.
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Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University, Tokyo, Japan.
| | - Keya Adhikari
- Department of Haematology, Nil Ratan Sircar Medical College, 138 A J C Bose Road, Kolkata, 700014, West Bengal, India
| | - Daniel Aeschlimann
- Matrix Biology &Tissue Repair Research Unit, School of Dentistry, College of Biomedical and Life Sciences, Cardiff University, Cardiff, Wales, UK
| | - Partha Chattopadhyay
- Department of General Medicine, College of Medicine & Sagore Dutta Hospital, 578 B T Road, Kamarhati-Kolkata, 700056, West Bengal, India
| | | | - Christiane S Hampe
- School of Medicine, University of Washington, 850 Republication, Seattle, WA, 98109, USA
| | - Jérôme Honnorat
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372, Lyon Cedex 08, France
- INSERM, UMR-S1028, CNRS, UMR-5292, Neuro-Oncology and Neuro-Inflammation Team, 7, Lyon Neuroscience Research Center, Rue Guillaume Paradin, 69372, Lyon Cedex 08, France
- National Reference Centre for Paraneoplastic Neurological Diseases, Hospices Civils de Lyon, Hôpital Neurologique, 69677, Bron, France
- Hospices Civils de Lyon, Neuro-oncology, Hôpital Neurologique, 69677, Bron, France
| | - Bastien Joubert
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372, Lyon Cedex 08, France
- INSERM, UMR-S1028, CNRS, UMR-5292, Neuro-Oncology and Neuro-Inflammation Team, 7, Lyon Neuroscience Research Center, Rue Guillaume Paradin, 69372, Lyon Cedex 08, France
| | - Shinji Kakei
- Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Jongho Lee
- Tokyo Metropolitan Institute of Medical Science, Tokyo, Japan
| | - Mario Manto
- Unité d'Etude du Mouvement, FNRS, Neurologie ULB-Erasme, 808 Route de Lennik, 1070, Brussels, Belgium
| | - Akiko Matsunaga
- Department of Neurology, University of Fukui Hospital, Fukui, Japan
| | | | - Kazunori Nanri
- Department of Neurology, Tokyo Medical University Hachioji Medical Center, Tokyo, Japan
| | - Priya Shanmugarajah
- Academic Department of Neurosciences, Royal Hallamshire Hospital, Sheffield, UK
| | - Makoto Yoneda
- Faculty of Nursing and Social Welfare Sciences, Fukui Prefectural University, Fukui, Japan
| | - Nobuhiro Yuki
- Departments of Medicine and Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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Abstract
Autoimmune movement disorders encapsulate a large and diverse group of neurologic disorders occurring either in isolation or accompanying more diffuse autoimmune encephalitic illnesses. The full range of movement phenomena has been described and, as they often occur in adults, many of the presentations can mimic neurodegenerative disorders, such as Huntington disease. Disorders may be ataxic, hypokinetic (parkinsonism), or hyperkinetic (myoclonus, chorea, tics, and other dyskinetic disorders). The autoantibody targets are diverse and include neuronal surface proteins such as leucine-rich, glioma-inactivated 1 (LGI1) and glycine receptors, as well as antibodies (such as intracellular antigens) that are markers of a central nervous system process mediated by CD8+ cytotoxic T cells. However, there are two conditions, stiff-person syndrome (also known as stiff-man syndrome) and progressive encephalomyelitis with rigidity and myoclonus (PERM), that are always autoimmune movement disorders. In some instances (such as Purkinje cell cytoplasmic antibody-1 (PCA-1) autoimmunity), antibodies detected in serum and cerebrospinal fluid can be indicative of a paraneoplastic cause, and may direct the cancer search. In other instances (such as 65kDa isoform of glutamic acid decarboxylase (GAD65) autoimmunity), a paraneoplastic cause is very unlikely, and early treatment with immunotherapy may promote improvement or recovery. Here we describe the different types of movement disorder and the clinical features and antibodies associated with them, and discuss treatment.
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Affiliation(s)
- Andrew Mckeon
- Departments of Neurology and Laboratory Medicine and Pathology, Mayo Clinic, Rochester, MN, USA.
| | - Angela Vincent
- Nuffield Department of Clinical Neurosciences, John Radcliffe Hospital, Oxford, UK
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23
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Manto M, Honnorat J, Hampe CS, Guerra-Narbona R, López-Ramos JC, Delgado-García JM, Saitow F, Suzuki H, Yanagawa Y, Mizusawa H, Mitoma H. Disease-specific monoclonal antibodies targeting glutamate decarboxylase impair GABAergic neurotransmission and affect motor learning and behavioral functions. Front Behav Neurosci 2015; 9:78. [PMID: 25870548 PMCID: PMC4375997 DOI: 10.3389/fnbeh.2015.00078] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 03/12/2015] [Indexed: 12/21/2022] Open
Abstract
Autoantibodies to the smaller isoform of glutamate decarboxylase (GAD) can be found in patients with type 1 diabetes and a number of neurological disorders, including stiff-person syndrome, cerebellar ataxia and limbic encephalitis. The detection of disease-specific autoantibody epitopes led to the hypothesis that distinct GAD autoantibodies may elicit specific neurological phenotypes. We explored the in vitro/in vivo effects of well-characterized monoclonal GAD antibodies. We found that GAD autoantibodies present in patients with stiff person syndrome (n = 7) and cerebellar ataxia (n = 15) recognized an epitope distinct from that recognized by GAD autoantibodies present in patients with type 1 diabetes mellitus (n = 10) or limbic encephalitis (n = 4). We demonstrated that the administration of a monoclonal GAD antibody representing this epitope specificity; (1) disrupted in vitro the association of GAD with γ-Aminobutyric acid containing synaptic vesicles; (2) depressed the inhibitory synaptic transmission in cerebellar slices with a gradual time course and a lasting suppressive effect; (3) significantly decreased conditioned eyelid responses evoked in mice, with no modification of learning curves in the classical eyeblink-conditioning task; (4) markedly impaired the facilitatory effect exerted by the premotor cortex over the motor cortex in a paired-pulse stimulation paradigm; and (5) induced decreased exploratory behavior and impaired locomotor function in rats. These findings support the specific targeting of GAD by its autoantibodies in the pathogenesis of stiff-person syndrome and cerebellar ataxia. Therapies of these disorders based on selective removal of such GAD antibodies could be envisioned.
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Affiliation(s)
- Mario Manto
- Unité d'Etude du Mouvement, FNRS Neurologie, ULB Erasme Brussels, Belgium
| | | | | | | | | | | | - Fumihito Saitow
- Department of Pharmacology, Nippon Medical School Tokyo, Japan
| | - Hidenori Suzuki
- Department of Pharmacology, Nippon Medical School Tokyo, Japan
| | - Yuchio Yanagawa
- Department of Genetic and Behavioral Neuroscience, Gunma University Graduate School of Medicine and JST, CREST, Maebashi City Gunma, Japan
| | | | - Hiroshi Mitoma
- Department of Medical Education, Tokyo Medical University Tokyo, Japan
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24
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Mitoma H, Yoneda M, Saitow F, Suzuki H, Matsunaga A, Ikawa M, Mizusawa H. Presynaptic dysfunction caused by cerebrospinal fluid from a patient with the ataxic form of Hashimoto's encephalopathy. ACTA ACUST UNITED AC 2014. [DOI: 10.1111/ncn3.105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hiroshi Mitoma
- Department of Medical Education; Tokyo Medical University; Tokyo Japan
| | - Makoto Yoneda
- Faculty of Nursing and Social Welfare Science; Fukui Prefectural University; Fukui Japan
| | - Fumihito Saitow
- Department of Pharmacology; Nippon Medical School; Tokyo Japan
| | - Hidenori Suzuki
- Department of Pharmacology; Nippon Medical School; Tokyo Japan
| | - Akiko Matsunaga
- Department of Neurology; University of Fukui Hospital; Fukui Japan
| | - Masamichi Ikawa
- Department of Neurology; University of Fukui Hospital; Fukui Japan
| | - Hidehiro Mizusawa
- Department of Neurology and Neurological Science; Graduate School of Medical and Dental Sciences; Tokyo Medical and Dental University; Tokyo Japan
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25
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Hampe CS, Petrosini L, De Bartolo P, Caporali P, Cutuli D, Laricchiuta D, Foti F, Radtke JR, Vidova V, Honnorat J, Manto M. Monoclonal antibodies to 65kDa glutamate decarboxylase induce epitope specific effects on motor and cognitive functions in rats. Orphanet J Rare Dis 2013; 8:82. [PMID: 23738610 PMCID: PMC3680042 DOI: 10.1186/1750-1172-8-82] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 05/29/2013] [Indexed: 01/02/2023] Open
Abstract
Background Stiff Person Syndrome (SPS) is a rare autoimmune movement disorder characterized by the presence of autoantibodies specific to the smaller isoform of glutamate decarboxylase (GAD65). A pathological role of these antibodies has been suggested by their capacity to inhibit GAD65 enzyme activity and by the observation that rats receiving cerebellar injections of GAD65Ab showed cerebellar motor hyperexcitability. To assess the effect of epitope-specific GAD65Ab on cognitive and motor functions, we conducted behavioral experiments in rats that received cerebellar injections with two distinct monoclonal GAD65Ab (b96.11 and b78). Methods Rats received three injections of GAD65Ab b96.11 (5 or 7 μg), GAD65Ab b78 (5 or 7 μg), or saline at the level of three cerebellar nuclei. Animals were submitted to neurological evaluation and Morris Water Maze (MWM) test. Cellular internalization of GAD65Ab was analyzed by Flow Cytometry, Fluorescence and Bright Field microscopy. Results Monoclonal GAD65Ab induced dose-dependent and epitope-specific effects on motor and cognitive functions. Injections of the higher dose altered motor and spatial procedural behaviors, while the lower dose induced only modest cerebellar motor symptoms and did not affect MWM performances. While b96.11 provoked immediate severe effects, which rapidly decreased, b78 induced moderate but prolonged effects. Both GAD65Ab were taken up by live cells in a dose-dependent manner. Conclusions Our findings support the hypothesis that epitope-specific GAD65Ab induce cerebellar dysfunction impairing motor and procedural abilities. This is the first demonstration of a critical role of cerebellar nuclei GAD65 enzyme in procedural spatial functions.
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Affiliation(s)
- Christiane S Hampe
- University of Washington, School of Medicine, SLU S-276, Seattle, WA 98109, USA.
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26
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Vega-Flores G, Rubio SE, Jurado-Parras MT, Gómez-Climent MÁ, Hampe CS, Manto M, Soriano E, Pascual M, Gruart A, Delgado-García JM. The GABAergic septohippocampal pathway is directly involved in internal processes related to operant reward learning. Cereb Cortex 2013; 24:2093-107. [PMID: 23479403 DOI: 10.1093/cercor/bht060] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We studied the role of γ-aminobutyric acid (GABA)ergic septohippocampal projections in medial septum (MS) self-stimulation of behaving mice. Self-stimulation was evoked in wild-type (WT) mice using instrumental conditioning procedures and in J20 mutant mice, a type of mouse with a significant deficit in GABAergic septohippocampal projections. J20 mice showed a significant modification in hippocampal activities, including a different response for input/output curves and the paired-pulse test, a larger long-term potentiation (LTP), and a delayed acquisition and lower performance in the MS self-stimulation task. LTP evoked at the CA3-CA1 synapse further decreased self-stimulation performance in J20, but not in WT, mice. MS self-stimulation evoked a decrease in the amplitude of field excitatory postsynaptic potentials (fEPSPs) at the CA3-CA1 synapse in WT, but not in J20, mice. This self-stimulation-dependent decrease in the amplitude of fEPSPs was also observed in the presence of another positive reinforcer (food collected during an operant task) and was canceled by the local administration of an antibody-inhibiting glutamate decarboxylase 65 (GAD65). LTP evoked in the GAD65Ab-treated group was also larger than in controls. The hippocampus has a different susceptibility to septal GABAergic inputs depending on ongoing cognitive processes, and the GABAergic septohippocampal pathway is involved in consummatory processes related to operant rewards.
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Affiliation(s)
- Germán Vega-Flores
- Division of Neurosciences, Pablo de Olavide University, Seville E-41013, Spain
| | - Sara E Rubio
- Developmental Neurobiology and Regeneration Laboratory, Institute for Research in Biomedicine, Barcelona, Spain Department of Cell Biology, University of Barcelona, Barcelona E-08028, Spain Centro de Investigación Biomédica en Red para Enfermedades Neurodegenerativas (CIBERNED-ISCIII), Spain
| | | | | | - Christiane S Hampe
- Department of Medicine, Division of Metabolism, Endocrinology and Nutrition, University of Washington, Seattle, USA
| | - Mario Manto
- Unité d'Etude du Movement, Hôpital Erasme-ULB, Bruxelles 1070, Belgium
| | - Eduardo Soriano
- Developmental Neurobiology and Regeneration Laboratory, Institute for Research in Biomedicine, Barcelona, Spain Department of Cell Biology, University of Barcelona, Barcelona E-08028, Spain Centro de Investigación Biomédica en Red para Enfermedades Neurodegenerativas (CIBERNED-ISCIII), Spain
| | - Marta Pascual
- Developmental Neurobiology and Regeneration Laboratory, Institute for Research in Biomedicine, Barcelona, Spain Department of Cell Biology, University of Barcelona, Barcelona E-08028, Spain Centro de Investigación Biomédica en Red para Enfermedades Neurodegenerativas (CIBERNED-ISCIII), Spain
| | - Agnès Gruart
- Division of Neurosciences, Pablo de Olavide University, Seville E-41013, Spain
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Nanri K, Niwa H, Mitoma H, Takei A, Ikeda J, Harada T, Okita M, Takeguchi M, Taguchi T, Mizusawa H. Low-Titer Anti-GAD-Antibody-Positive Cerebellar Ataxia. THE CEREBELLUM 2012; 12:171-5. [DOI: 10.1007/s12311-012-0411-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Rout UK, Mungan NK, Dhossche DM. Presence of GAD65 autoantibodies in the serum of children with autism or ADHD. Eur Child Adolesc Psychiatry 2012; 21:141-7. [PMID: 22323074 DOI: 10.1007/s00787-012-0245-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 01/13/2012] [Indexed: 11/30/2022]
Abstract
Antibodies against glutamic acid decarboxylase 65 (GAD65) have been detected in the serum of patients with several neurological disorders. The presence of antibodies against GAD65 has not yet been examined in the serum of patients with neurodevelopmental disorders such as autism or attention-deficit/hyperactivity disorder (ADHD). In this study, GAD65 antibodies and total IgG were assayed in the serum of normal subjects and patients diagnosed with autism or ADHD. GAD65 antibodies were detected in the serum of 15% of children with autism (N = 20), 27% of children with ADHD (N = 15) and of none of the controls (N = 14). The serum of 60% of autistic and 53% of ADHD patients reacted with Purkinje neurons in mouse cerebellum. Serum from 20% of ADHD patients reacted also with the cells in the molecular and granule cell layers and cells in the vicinity of the Purkinje neurons. No association was found between the titer of GAD65 antibodies and total IgG levels, and presence of seizures or mental retardation. None of the ADHD patients were diagnosed with mental retardation. Serum anti-GAD65 antibodies may be a common marker of subgroups of patients with autism and ADHD. Reactions of serum antibodies with the cells in the cerebellum in these patients suggest direct effects on brain function. The subgroup of children with autism and ADHD that tests positive for GAD65 antibodies needs further characterization in a larger study.
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Affiliation(s)
- Ujjwal K Rout
- Department of Surgery, University of Mississippi Medical Center, Clinical Sciences Building, Room L020, Jackson, MS, 39216, USA.
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Caietta E, Halbert C, Lépine A, Khammar A, Cano A, Gavaret M, Mancini J, Villeneuve N, Chabrol B, Simonin G, Reynaud R, Milh M. [Association of type 1 diabetes mellitus and epilepsy in children. A cohort of 10 cases]. Arch Pediatr 2011; 19:9-16. [PMID: 22112607 DOI: 10.1016/j.arcped.2011.10.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 08/21/2011] [Accepted: 10/10/2011] [Indexed: 10/15/2022]
Abstract
UNLABELLED The association of type 1 diabetes mellitus (DM) and epilepsy has been previously reported. However, the physiopathology of this association remains misunderstood. OBJECTIVE To describe epilepsy combined with type 1 DM in children. METHODS Retrospective monocentric study of all the epileptic and type 1 diabetic children consulting at the Timone University Hospital, Marseille, France. For each patient, the type of epilepsy and its electroclinical and radiographic characteristics were studied as well as the type of diabetes (biological characteristics, glycemic control), and the onset of these 2 diseases. RESULTS Ten patients are reported. Five suffered from generalized epilepsy (4 idiopathic, 1 nonidiopathic) and 5 from focal epilepsy (4 non-idiopathic, 1 idiopathic). For most of these cases, presence of GAD (glutamic acid decarboxylase) autoantibodies were confirmed and epilepsy followed diabetes. CONCLUSIONS The 2 most common types of epilepsy in this association are idiopathic generalized epilepsy and non-idiopathic temporal epilepsy. Several mechanisms could be involved (immune, glycemia, and genetic disorders).
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Affiliation(s)
- E Caietta
- Service de neurologie pédiatrique, Assistance publique-Hôpitaux de Marseille, CHU La Timone, 264, rue Saint-Pierre, 13005 Marseille, France.
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Hijazi J, Bedat-Millet AL, Hannequin D. Le syndrome de l’homme raide et autres maladies neurologiques associées aux anticorps anti-GAD. Rev Med Interne 2010; 31:23-8. [DOI: 10.1016/j.revmed.2009.01.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Revised: 12/11/2008] [Accepted: 01/22/2009] [Indexed: 11/16/2022]
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Ishida K, Mitoma H, Mizusawa H. Reversibility of cerebellar GABAergic synapse impairment induced by anti-glutamic acid decarboxylase autoantibodies. J Neurol Sci 2008; 271:186-90. [PMID: 18534624 DOI: 10.1016/j.jns.2008.04.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2007] [Revised: 04/08/2008] [Accepted: 04/17/2008] [Indexed: 11/19/2022]
Abstract
Anti-glutamic acid decarboxylase autoantibodies (GAD-Abs) are found in some patients with cerebellar ataxia. We reported previously that CSF IgGs depress cerebellar GABAergic synaptic transmissions by a presynaptic mechanism. Using whole-cell recordings from rat cerebellar slices, we found in the present study that CSF IgG-induced depressive effects were abolished by absorption of GAD-Abs using recombinant GAD. Furthermore, forskolin, an activator of cAMP, recovered the CSF IgG-induced reduction of GABA release. Our results provide evidence that GAD-Abs in the CSF elicited physiopathological effects on cerebellar GABA synapses in vitro and that such synaptic impairment was reversible.
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Affiliation(s)
- Kazuyuki Ishida
- Department of Neurology and Neurological Science, Tokyo Medical and Dental University, Graduate School of Medical and Dental Sciences, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan.
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Honnorat J. Des autoanticorps peuvent-ils être responsables d’un syndrome neurologique central ? Rev Neurol (Paris) 2008; 164:403-4. [DOI: 10.1016/j.neurol.2008.04.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Bonnan M, Cabre P, Olindo S, Signate A, Saint-Vil M, Smadja D. [Steroid treatment in four cases of anti-GAD cerebellar ataxia]. Rev Neurol (Paris) 2008; 164:427-33. [PMID: 18555874 DOI: 10.1016/j.neurol.2008.02.032] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2007] [Revised: 12/09/2007] [Accepted: 02/08/2008] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Few neurological diseases are linked with anti-glutamic acid decarboxylase antibodies (GAD-ab); stiff man syndrome is an example. Cerebellar ataxia is a new feature of this expanding spectrum. No therapeutic trial is yet available in these diseases. We here report on four patients suffering from cerebellar ataxia linked with GAD-ab and review the data in the literature on this recently described syndrome. METHOD We conducted an open trial with monthly pulsed steroids. Steroid pulses were given six months followed with placebo for another six months. Main clinical and biological parameters were monitored monthly (International Cooperative Cerebellar Ataxia Rating Scale [ICARS] and GAD-ab). RESULT The clinical response was found limited and inconstant. Transient decline in GAD-ab level was noted in two patients. Moreover, GAD-ab level was found highly variable and did not correlate with clinical parameters. DISCUSSION Cerebellar ataxia with GAD-ab is an increasingly described syndrome. Outcome can be severe, leading to definitive cerebellar atrophy. Diagnosis is supported by high level of serum GAD-ab with intrathecal secretion. Experimental data have suggested a direct excitotoxic effect of GAD-ab on Purkinje cells. Response to various treatments is often disappointing. Improvement has been obtained with veinoglobulins in individual patients. A weak clinical and biological response was associated with monthly steroid pulses.
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Affiliation(s)
- M Bonnan
- Service de neurologie, hôpital Pierre-Zobda-Quitman, centre hospitalier universitaire de Fort-de-France, B.P. 632, 97261 Fort-de-France cedex, France.
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Carta M, Murru L, Barabino E, Talani G, Sanna E, Biggio G. Isoniazid-induced reduction in GABAergic neurotransmission alters the function of the cerebellar cortical circuit. Neuroscience 2008; 154:710-9. [PMID: 18456415 DOI: 10.1016/j.neuroscience.2008.02.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Revised: 01/25/2008] [Accepted: 02/16/2008] [Indexed: 11/16/2022]
Abstract
The cerebellar cortex contributes to the control of movement, coordination, and certain cognitive functions. The cerebellar network is composed of five different types of neurons that are wired together in a repetitive module. Given that four of these five neurons synthesize and release GABA, this inhibitory neurotransmitter plays a central role in regulation of the excitability and correct functioning of the cerebellar cortex. We have now used isoniazid, an inhibitor of glutamic acid decarboxylase, the enzyme responsible for the synthesis of GABA, to evaluate the contribution of GABAergic transmission in different types of cerebellar cortical neurons to the functioning of the cerebellar circuit. Parasagittal cerebellar slices were prepared from 28- to 40-day-old male rats and were subjected to patch-clamp recording in the voltage- or current-clamp mode. Exposure of the tissue slices to isoniazid (10 mM) resulted in a decrease in the level of GABAergic transmission in Purkinje cells and a consequent increase in the firing rate of spontaneous action potentials that was apparent after 40 min. In granule neurons, isoniazid reduced both tonic and phasic GABAergic currents and thereby altered the flow of information across the cerebellar cortex. Our data support the notion that the amount of GABA at the synaptic level is a major determinant of the excitability of the cerebellar cortex, and they suggest that isoniazid may be a useful tool with which to study the function of the cerebellar network.
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Affiliation(s)
- M Carta
- Department of Experimental Biology Bernardo Loddo, Section of Neuroscience, University of Cagliari, Cittadella Universitaria, SS 554, Km 4,500, Monserrato CA, Italy.
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Frisullo G, Della Marca G, Mirabella M, Caggiula M, Broccolini A, Rubino M, Mennuni G, Tonali PA, Batocchi AP. A human anti-neuronal autoantibody against GABAB receptor induces experimental autoimmune agrypnia. Exp Neurol 2007; 204:808-18. [PMID: 17336294 DOI: 10.1016/j.expneurol.2007.01.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2006] [Revised: 01/10/2007] [Accepted: 01/11/2007] [Indexed: 11/18/2022]
Abstract
In the serum and cerebrospinal fluid of a patient with recurrent acute episodes of respiratory crises, autonomic symptoms and total insomnia (agrypnia), we identified a novel anti-neural complement fixing antibody directed against GABA(B) receptor (GABA(B)R). Patient purified IgG recognized a band of approximately 110 kDa on protein extracts of mouse cerebellum, cortex and brainstem and immunolabelled cultured Chinese hamster ovary (CHO) cells, transfected with human GABA(B)R1 and rat GABA(B)R2 receptors. Western blot analysis of transfected CHO homogenates showed the same band using both patient purified IgG and anti-GABA(B)R1 antibody. In order to verify the pathogenic role of these purified antibodies, we injected patient IgG intrathecally into cisterna magna of C57BL/6 mice pre-implanted with EEG electrodes and we observed severe ataxia followed by breathing depression and total suppression of slow wave sleep, as evidenced by EEG recording, in a dose-dependent manner. Immunohistochemistry on brain sections of mice injected with patient IgG showed the simultaneous presence of bound human IgG and C5b-9 deposits on Purkinje cells and cerebellar granular layer. After incubation with anti-GABA(B)R antibody, a marked reduction of receptor immunostaining was found with relative sparing of neuronal architecture. In conclusion we recognized an anti-neuronal autoantibody directed against GABA(B)R that is associated with autoimmune agrypnia and we showed that our patient purified IgG was able to induce in mice experimental autoimmune agrypnia characterized by a complex neurological syndrome affecting several CNS functions.
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Affiliation(s)
- Giovanni Frisullo
- Department of Neuroscience, Institute of Neurology, Catholic University, Largo Gemelli 8, 00168 Rome, Italy
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Ishida K, Mitoma H, Wada Y, Oka T, Shibahara J, Saito Y, Murayama S, Mizusawa H. Selective loss of Purkinje cells in a patient with anti-glutamic acid decarboxylase antibody-associated cerebellar ataxia. J Neurol Neurosurg Psychiatry 2007; 78:190-2. [PMID: 17119008 PMCID: PMC2077656 DOI: 10.1136/jnnp.2006.091116] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Anti-glutamic acid decarboxylase antibody is associated with the development of progressive cerebellar ataxia and slowly progressive insulin-dependent diabetes mellitus. Previously, the neurophysiological characteristics of IgG in the cerebrospinal fluid of a patient with anti-glutamic acid decarboxylase antibody-associated progressive cerebellar ataxia and slowly progressive insulin-dependent diabetes mellitus were reported. Using a voltage-gated whole-cell recording technique, it was observed that the IgG in the cerebrospinal fluid of the patient selectively suppressed the inhibitory postsynaptic currents in the Purkinje cells. The patient died from aspiration pneumonia. Postmortem examination showed almost complete depletion of the Purkinje cells with Bergmann gliosis. Therefore, the main cause of cerebellar ataxia observed in this case may be attributed to the near-complete depletion of the Purkinje cells. In this paper, the pathomechanisms underlying Purkinje cell damage are discussed.
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Affiliation(s)
- Kazuyuki Ishida
- Department of Neurology, Tamagawa Hospital, Setagaya-ku, Tokyo, Japan.
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Raju R, Foote J, Banga JP, Hall TR, Padoa CJ, Dalakas MC, Ortqvist E, Hampe CS. Analysis of GAD65 autoantibodies in Stiff-Person syndrome patients. THE JOURNAL OF IMMUNOLOGY 2006; 175:7755-62. [PMID: 16301686 DOI: 10.4049/jimmunol.175.11.7755] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Autoantibodies to the 65-kDa isoform of glutamate decarboxylase GAD65 (GAD65Ab) are strong candidates for a pathological role in Stiff-Person syndrome (SPS). We have analyzed the binding specificity of the GAD65Ab in serum and cerebrospinal fluid (CSF) of 12 patients with SPS by competitive displacement studies with GAD65-specific rFab-derived from a number of human and mouse mAbs specific for different determinants on the Ag. We demonstrate considerable differences in the epitope specificity when comparing paired serum and CSF samples, suggesting local stimulation of B cells in the CSF compartment of these patients. Moreover, these autoantibodies strongly inhibit the enzymatic activity of GAD65, thus blocking the formation of the neurotransmitter gamma-aminobutyric acid. The capacity of the sera to inhibit the enzymatic activity of GAD65 correlated with their binding to a conformational C-terminal Ab epitope. Investigation of the inhibitory mechanism revealed that the inhibition could not be overcome by high concentrations of glutamate or the cofactor pyridoxal phosphate, suggesting a noncompetitive inhibitory mechanism. Finally, we identified a linear epitope on amino acids residues 4-22 of GAD65 that was recognized solely by autoantibodies from patients with SPS but not by serum from type 1 diabetes patients. A mAb (N-GAD65 mAb) recognizing this N-terminal epitope was successfully humanized to enhance its potential therapeutic value by reducing its overall immunogenicity.
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Affiliation(s)
- Raghavanpillai Raju
- Neuromuscular Diseases Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA
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