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Buggia-Prévot V, Thinakaran G. Significance of transcytosis in Alzheimer's disease: BACE1 takes the scenic route to axons. Bioessays 2015; 37:888-98. [PMID: 26126792 PMCID: PMC4512854 DOI: 10.1002/bies.201500019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Neurons have developed elaborate mechanisms for sorting of proteins to their destination in dendrites and axons as well as dynamic local trafficking. Recent evidence suggests that polarized axonal sorting of β-site converting enzyme 1 (BACE1), a type I transmembrane aspartyl protease involved in Alzheimer's disease (AD) pathogenesis, entails an unusual journey. In hippocampal neurons, BACE1 internalized from dendrites is conveyed in recycling endosomes via unidirectional retrograde transport towards the soma and sorted to axons where BACE1 becomes enriched. In comparison to other transmembrane proteins that undergo transcytosis or elimination in somatodendritic compartment, vectorial transport of internalized BACE1 in dendrites is unique and intriguing. Dysfunction of protein transport contributes to pathogenesis of AD and other neurodegenerative diseases. Therefore, characterization of BACE1 transcytosis is an important addition to the multiple lines of evidence that highlight the crucial role played by endosomal trafficking pathway as well as axonal sorting mechanisms in AD pathogenesis.
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Affiliation(s)
- Virginie Buggia-Prévot
- Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, IL 60637
| | - Gopal Thinakaran
- Departments of Neurobiology, Neurology, and Pathology, The University of Chicago, Chicago, IL 60637
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Joubert B, Honnorat J. Autoimmune channelopathies in paraneoplastic neurological syndromes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:2665-76. [PMID: 25883091 DOI: 10.1016/j.bbamem.2015.04.003] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2014] [Revised: 03/10/2015] [Accepted: 04/03/2015] [Indexed: 01/17/2023]
Abstract
Paraneoplastic neurological syndromes and autoimmune encephalitides are immune neurological disorders occurring or not in association with a cancer. They are thought to be due to an autoimmune reaction against neuronal antigens ectopically expressed by the underlying tumour or by cross-reaction with an unknown infectious agent. In some instances, paraneoplastic neurological syndromes and autoimmune encephalitides are related to an antibody-induced dysfunction of ion channels, a situation that can be labelled as autoimmune channelopathies. Such functional alterations of ion channels are caused by the specific fixation of an autoantibody upon its target, implying that autoimmune channelopathies are usually highly responsive to immuno-modulatory treatments. Over the recent years, numerous autoantibodies corresponding to various neurological syndromes have been discovered and their mechanisms of action partially deciphered. Autoantibodies in neurological autoimmune channelopathies may target either directly ion channels or proteins associated to ion channels and induce channel dysfunction by various mechanisms generally leading to the reduction of synaptic expression of the considered channel. The discovery of those mechanisms of action has provided insights on the regulation of the synaptic expression of the altered channels as well as the putative roles of some of their functional subdomains. Interestingly, patients' autoantibodies themselves can be used as specific tools in order to study the functions of ion channels. This article is part of a Special Issue entitled: Membrane channels and transporters in cancers.
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Affiliation(s)
- Bastien Joubert
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France; INSERM, UMR-S1028, CNRS, UMR-5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team, 7, Rue Guillaume Paradin, Lyon Cedex 08F-69372, France
| | - Jérôme Honnorat
- University Lyon 1, University Lyon, Rue Guillaume Paradin, 69372 Lyon Cedex 08, France; INSERM, UMR-S1028, CNRS, UMR-5292, Lyon Neuroscience Research Center, Neuro-Oncology and Neuro-Inflammation Team, 7, Rue Guillaume Paradin, Lyon Cedex 08F-69372, 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, F-69677 Bron, France.
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Miura Y, Devaux JJ, Fukami Y, Manso C, Belghazi M, Wong AHY, Yuki N. Contactin 1 IgG4 associates to chronic inflammatory demyelinating polyneuropathy with sensory ataxia. Brain 2015; 138:1484-91. [PMID: 25808373 DOI: 10.1093/brain/awv054] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2014] [Accepted: 01/10/2015] [Indexed: 11/12/2022] Open
Abstract
A Spanish group recently reported that four patients with chronic inflammatory demyelinating polyneuropathy carrying IgG4 autoantibodies against contactin 1 showed aggressive symptom onset and poor response to intravenous immunoglobulin. We aimed to describe the clinical and serological features of Japanese chronic inflammatory demyelinating polyneuropathy patients displaying the anti-contactin 1 antibodies. Thirteen of 533 (2.4%) patients with chronic inflammatory demyelinating polyneuropathy had anti-contactin 1 IgG4 whereas neither patients from disease or normal control subjects did (P = 0.02). Three of 13 (23%) patients showed subacute symptom onset, but all of the patients presented with sensory ataxia. Six of 10 (60%) anti-contactin 1 antibody-positive patients had poor response to intravenous immunoglobulin, whereas 8 of 11 (73%) antibody-positive patients had good response to corticosteroids. Anti-contactin 1 IgG4 antibodies are a possible biomarker to guide treatment option.
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Affiliation(s)
- Yumako Miura
- 1 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Jérôme J Devaux
- 2 Aix-Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France 1 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Yuki Fukami
- 1 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Constance Manso
- 2 Aix-Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France
| | - Maya Belghazi
- 2 Aix-Marseille Université, CNRS, CRN2M-UMR 7286, Marseille, France
| | - Anna Hiu Yi Wong
- 1 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Nobuhiro Yuki
- 1 Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 3 Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
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Trimmer JS. Subcellular localization of K+ channels in mammalian brain neurons: remarkable precision in the midst of extraordinary complexity. Neuron 2015; 85:238-56. [PMID: 25611506 DOI: 10.1016/j.neuron.2014.12.042] [Citation(s) in RCA: 155] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Potassium channels (KChs) are the most diverse ion channels, in part due to extensive combinatorial assembly of a large number of principal and auxiliary subunits into an assortment of KCh complexes. Their structural and functional diversity allows KChs to play diverse roles in neuronal function. Localization of KChs within specialized neuronal compartments defines their physiological role and also fundamentally impacts their activity, due to localized exposure to diverse cellular determinants of channel function. Recent studies in mammalian brain reveal an exquisite refinement of KCh subcellular localization. This includes axonal KChs at the initial segment, and near/within nodes of Ranvier and presynaptic terminals, dendritic KChs found at sites reflecting specific synaptic input, and KChs defining novel neuronal compartments. Painting the remarkable diversity of KChs onto the complex architecture of mammalian neurons creates an elegant picture of electrical signal processing underlying the sophisticated function of individual neuronal compartments, and ultimately neurotransmission and behavior.
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Affiliation(s)
- James S Trimmer
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis, Davis, CA 95616, USA; Department of Physiology and Membrane Biology, University of California, Davis, Davis, CA 95616, USA.
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Svahn J, Antoine JC, Camdessanché JP. Pathophysiology and biomarkers in chronic inflammatory demyelinating polyradiculoneuropathies. Rev Neurol (Paris) 2014; 170:808-17. [PMID: 25459126 DOI: 10.1016/j.neurol.2014.10.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is an acquired dysimmune disorder characterized by strong heterogeneity in terms of clinical manifestations, prognostic and response to treatment. To date, its pathophysiology and potential target antigens are not totally identified despite substantial progress in the understanding of the involved molecular mechanisms. Recent researches in the field have underlined the importance of cell-mediated immunity (lymphocytesT CD4+, CD8+ and macrophages), the breakdown of blood-nerve barrier, a failure of T-cell regulation, and the disruption of nodal and paranodal organization at the node of Ranvier. This last point is possibly mediated by autoantibodies towards axoglial adhesion molecules which may disrupt sodium and potassium voltage-gated channels clustering leading to a failure of saltatory conduction and the apparition of conduction blocks. The purpose of this article is to overview the main pathophysiologic mechanisms and biomarkers identified in CIDP.
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Affiliation(s)
- J Svahn
- Inserm 1028 CNRS UMR5292, équipe neuro-oncologie neuro-inflammation, faculté de médecine Jacques-Lisfranc, 42023 Saint-Étienne cedex 2, France; Université Claude-Bernard Lyon 1, 69003 Lyon, France
| | - J-C Antoine
- Inserm 1028 CNRS UMR5292, équipe neuro-oncologie neuro-inflammation, faculté de médecine Jacques-Lisfranc, 42023 Saint-Étienne cedex 2, France; Service de neurologie, hôpital Nord, CHU de Saint-Étienne, 42055 Saint-Étienne cedex 02, France; Centre référent maladies neuromusculaires rares Rhône-Alpes, CHU de Saint-Étienne, 42055 Saint-Étienne cedex 02, France
| | - J-P Camdessanché
- Inserm 1028 CNRS UMR5292, équipe neuro-oncologie neuro-inflammation, faculté de médecine Jacques-Lisfranc, 42023 Saint-Étienne cedex 2, France; Service de neurologie, hôpital Nord, CHU de Saint-Étienne, 42055 Saint-Étienne cedex 02, France; Centre référent maladies neuromusculaires rares Rhône-Alpes, CHU de Saint-Étienne, 42055 Saint-Étienne cedex 02, France.
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Peripheral nerve proteins as potential autoantigens in acute and chronic inflammatory demyelinating polyneuropathies. Autoimmun Rev 2014; 13:1070-8. [DOI: 10.1016/j.autrev.2014.08.005] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2014] [Accepted: 06/27/2014] [Indexed: 01/06/2023]
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