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Yang Z, Marcoci C, Öztürk HK, Giama E, Yenicelik AG, Slanař O, Linington C, Desai R, Smith KJ. Tissue Hypoxia and Associated Innate Immune Factors in Experimental Autoimmune Optic Neuritis. Int J Mol Sci 2024; 25:3077. [PMID: 38474322 DOI: 10.3390/ijms25053077] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 03/03/2024] [Accepted: 03/04/2024] [Indexed: 03/14/2024] Open
Abstract
Visual loss in acute optic neuritis is typically attributed to axonal conduction block due to inflammatory demyelination, but the mechanisms remain unclear. Recent research has highlighted tissue hypoxia as an important cause of neurological deficits and tissue damage in both multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) and, here, we examine whether the optic nerves are hypoxic in experimental optic neuritis induced in Dark Agouti rats. At both the first and second peaks of disease expression, inflamed optic nerves labelled significantly for tissue hypoxia (namely, positive for hypoxia inducible factor-1α (HIF1α) and intravenously administered pimonidazole). Acutely inflamed nerves were also labelled significantly for innate markers of oxidative and nitrative stress and damage, including superoxide, nitric oxide and 3-nitrotyrosine. The density and diameter of capillaries were also increased. We conclude that in acute optic neuritis, the optic nerves are hypoxic and come under oxidative and nitrative stress and damage. Tissue hypoxia can cause mitochondrial failure and thus explains visual loss due to axonal conduction block. Tissue hypoxia can also induce a damaging oxidative and nitrative environment. The findings indicate that treatment to prevent tissue hypoxia in acute optic neuritis may help to restore vision and protect from damaging reactive oxygen and nitrogen species.
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Affiliation(s)
- Zhiyuan Yang
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Cristina Marcoci
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Hatice Kübra Öztürk
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Eleni Giama
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Ayse Gertrude Yenicelik
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Ondřej Slanař
- Institute of Pharmacology, First Faculty of Medicine, Charles University and General University Hospital in Prague, 12800 Prague, Czech Republic
| | - Christopher Linington
- School of Infection and Immunity, The Sir Graeme Davies Building, Glasgow G12 8TA, UK
| | - Roshni Desai
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
| | - Kenneth J Smith
- Department of Neuroinflammation, UCL Queen Square Institute of Neurology, University College London, London WC1N 1PJ, UK
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Buscho SE, Xia F, Shi S, Lin JL, Szczesny B, Zhang W, Motamedi M, Liu H. Non-Invasive Evaluation of Retinal Vascular Alterations in a Mouse Model of Optic Neuritis Using Laser Speckle Flowgraphy and Optical Coherence Tomography Angiography. Cells 2023; 12:2685. [PMID: 38067113 PMCID: PMC10705764 DOI: 10.3390/cells12232685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 11/04/2023] [Accepted: 11/20/2023] [Indexed: 12/18/2023] Open
Abstract
Optic neuritis, a characteristic feature of multiple sclerosis (MS), involves the inflammation of the optic nerve and the degeneration of retinal ganglion cells (RGCs). Although previous studies suggest that retinal blood flow alterations occur during optic neuritis, the precise location, the degree of impairment, and the underlying mechanisms remain unclear. In this study, we utilized two emerging non-invasive imaging techniques, laser speckle flowgraphy (LSFG) and optical coherence tomography angiography (OCTA), to investigate retinal vascular changes in a mouse model of MS, known as experimental autoimmune encephalomyelitis (EAE). We associated these changes with leukostasis, RGC injury, and the overall progression of EAE. LSFG imaging revealed a progressive reduction in retinal blood flow velocity and increased vascular resistance near the optic nerve head in the EAE model, indicating impaired ocular blood flow. OCTA imaging demonstrated significant decreases in vessel density, number of junctions, and total vessel length in the intermediate and deep capillary plexus of the EAE mice. Furthermore, our analysis of leukostasis revealed a significant increase in adherent leukocytes in the retinal vasculature of the EAE mice, suggesting the occurrence of vascular inflammation in the early development of EAE pathology. The abovechanges preceded or were accompanied by the characteristic hallmarks of optic neuritis, such as RGC loss and reduced visual acuity. Overall, our study sheds light on the intricate relationship between retinal vascular alterations and the progression of optic neuritis as well as MS clinical score. It also highlights the potential for the development of image-based biomarkers for the diagnosis and monitoring of optic neuritis as well as MS, particularly in response to emerging treatments.
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Affiliation(s)
- Seth E. Buscho
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
| | - Fan Xia
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
| | - Shuizhen Shi
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
| | - Jonathan L. Lin
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Bartosz Szczesny
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
- Department of Anesthesiology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Wenbo Zhang
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
- Department of Neurobiology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Massoud Motamedi
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
| | - Hua Liu
- Department of Ophthalmology and Visual Sciences, University of Texas Medical Branch, Galveston, TX 77555, USA; (S.E.B.); (F.X.); (S.S.); (J.L.L.); (B.S.); (W.Z.); (M.M.)
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3
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Ouédraogo O, Balthazard R, Mamane VH, Jamann H, Millette F, Daigneault A, Arbour N, Larochelle C. Investigating anti-inflammatory and immunomodulatory properties of brivaracetam and lacosamide in experimental autoimmune encephalomyelitis (EAE). Epilepsy Res 2023; 192:107125. [PMID: 36963302 DOI: 10.1016/j.eplepsyres.2023.107125] [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: 12/24/2022] [Revised: 02/20/2023] [Accepted: 03/13/2023] [Indexed: 03/15/2023]
Abstract
PURPOSE Inflammation plays a role in drug-resistant epilepsy (DRE). We have previously reported an increased proportion of CD4 T cells displaying a pro-inflammatory profile in the peripheral blood of adults with DRE. Specific anti-epileptic drugs (AEDs) exhibit immunomodulatory properties that could increase the risk of infections but also contribute to their beneficial impact on DRE and other neurological diseases. The impact of novel generation AEDs on the profile of immune cells and on neuroinflammatory processes remains unclear. METHODS We compared the influence of brivaracetam and lacosamide on the activation of human and murine peripheral immune cells in vitro and in vivo in active experimental autoimmune encephalomyelitis (EAE), a common mouse model of central nervous system inflammation. RESULTS We found that brivaracetam and lacosamide at 2.5 μg/ml did not impair the survival and activation of human immune cells, but a higher dose of 25 μg/ml decreased mitogen-induced proliferation of CD8 T cells in vitro. Exposure to high doses of brivaracetam, and to a lesser extent lacosamide, reduced the proportion of CD25+ and CD107a+ CD8+ human T cells in vitro, and the frequency of CNS-infiltrating CD8+ T cells at EAE onset and CD11b+ myeloid cells at peak in vivo. Prophylactic administration of brivaracetam or lacosamide did not delay EAE onset but significantly improved the clinical course in the chronic phase of EAE compared to control. CONCLUSION Novel generation AEDs do not impair the response to immunization with MOG peptide but improve the course of EAE, possibly through a reduction of neuroaxonal damage.
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Affiliation(s)
- Oumarou Ouédraogo
- Department of Microbiology, Infectiology and Immunology, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Renaud Balthazard
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Victoria Hannah Mamane
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Hélène Jamann
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Florence Millette
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Audrey Daigneault
- Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Nathalie Arbour
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada
| | - Catherine Larochelle
- Department of Neurosciences, Faculty of Medicine, University of Montreal, Montreal, QC, Canada; Research Center of the University of Montreal Hospital Center, Montreal, QC, Canada.
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Cui J, Zhao S, Li Y, Zhang D, Wang B, Xie J, Wang J. Regulated cell death: discovery, features and implications for neurodegenerative diseases. Cell Commun Signal 2021; 19:120. [PMID: 34922574 PMCID: PMC8684172 DOI: 10.1186/s12964-021-00799-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 10/30/2021] [Indexed: 12/18/2022] Open
Abstract
Regulated cell death (RCD) is a ubiquitous process in living organisms that is essential for tissue homeostasis or to restore biological balance under stress. Over the decades, various forms of RCD have been reported and are increasingly being found to involve in human pathologies and clinical outcomes. We focus on five high-profile forms of RCD, including apoptosis, pyroptosis, autophagy-dependent cell death, necroptosis and ferroptosis. Cumulative evidence supports that not only they have different features and various pathways, but also there are extensive cross-talks between modes of cell death. As the understanding of RCD pathway in evolution, development, physiology and disease continues to improve. Here we review an updated classification of RCD on the discovery and features of processes. The prominent focus will be placed on key mechanisms of RCD and its critical role in neurodegenerative disease. Video abstract.
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Affiliation(s)
- Juntao Cui
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
| | - Suhan Zhao
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- School of Clinical Medicine, Qingdao University, Qingdao, 266071 China
| | - Yinghui Li
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
| | - Danyang Zhang
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
| | - Bingjing Wang
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
| | - Junxia Xie
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
| | - Jun Wang
- School of Basic Medicine, Qingdao University, Qingdao, 266071 China
- Institute of Brain Science and Disease, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Qingdao University, Qingdao, 266071 China
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5
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Duncan GJ, Simkins TJ, Emery B. Neuron-Oligodendrocyte Interactions in the Structure and Integrity of Axons. Front Cell Dev Biol 2021; 9:653101. [PMID: 33763430 PMCID: PMC7982542 DOI: 10.3389/fcell.2021.653101] [Citation(s) in RCA: 50] [Impact Index Per Article: 16.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 02/15/2021] [Indexed: 12/12/2022] Open
Abstract
The myelination of axons by oligodendrocytes is a highly complex cell-to-cell interaction. Oligodendrocytes and axons have a reciprocal signaling relationship in which oligodendrocytes receive cues from axons that direct their myelination, and oligodendrocytes subsequently shape axonal structure and conduction. Oligodendrocytes are necessary for the maturation of excitatory domains on the axon including nodes of Ranvier, help buffer potassium, and support neuronal energy metabolism. Disruption of the oligodendrocyte-axon unit in traumatic injuries, Alzheimer's disease and demyelinating diseases such as multiple sclerosis results in axonal dysfunction and can culminate in neurodegeneration. In this review, we discuss the mechanisms by which demyelination and loss of oligodendrocytes compromise axons. We highlight the intra-axonal cascades initiated by demyelination that can result in irreversible axonal damage. Both the restoration of oligodendrocyte myelination or neuroprotective therapies targeting these intra-axonal cascades are likely to have therapeutic potential in disorders in which oligodendrocyte support of axons is disrupted.
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Affiliation(s)
- Greg J. Duncan
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, OR, United States
| | - Tyrell J. Simkins
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, OR, United States
- Vollum Institute, Oregon Health & Science University, Portland, OR, United States
- Department of Neurology, VA Portland Health Care System, Portland, OR, United States
| | - Ben Emery
- Jungers Center for Neurosciences Research, Department of Neurology, Oregon Health & Science University, Portland, OR, United States
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6
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Cunniffe N, Vuong KA, Ainslie D, Baker D, Beveridge J, Bickley S, Camilleri P, Craner M, Fitzgerald D, de la Fuente AG, Giovannoni G, Gray E, Hazlehurst L, Kapoor R, Kaur R, Kozlowski D, Lumicisi B, Mahad D, Neumann B, Palmer A, Peruzzotti-Jametti L, Pluchino S, Robertson J, Rothaul A, Shellard L, Smith KJ, Wilkins A, Williams A, Coles A. Systematic approach to selecting licensed drugs for repurposing in the treatment of progressive multiple sclerosis. J Neurol Neurosurg Psychiatry 2021; 92:295-302. [PMID: 33184094 DOI: 10.1136/jnnp-2020-324286] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 09/08/2020] [Accepted: 10/13/2020] [Indexed: 12/20/2022]
Abstract
OBJECTIVE To establish a rigorous, expert-led, evidence-based approach to the evaluation of licensed drugs for repurposing and testing in clinical trials of people with progressive multiple sclerosis (MS). METHODS We long-listed licensed drugs with evidence of human safety, blood-brain barrier penetrance and demonstrable efficacy in at least one animal model, or mechanistic target, agreed by a panel of experts and people with MS to be relevant to the pathogenesis of progression. We systematically reviewed the preclinical and clinical literature for each compound, condensed this into a database of summary documents and short-listed drugs by scoring each one of them. Drugs were evaluated for immediate use in a clinical trial, and our selection was scrutinised by a final independent expert review. RESULTS From a short list of 55 treatments, we recommended four treatments for immediate testing in progressive MS: R-α-lipoic acid, metformin, the combination treatment of R-α-lipoic acid and metformin, and niacin. We also prioritised clemastine, lamotrigine, oxcarbazepine, nimodipine and flunarizine. CONCLUSIONS We report a standardised approach for the identification of candidate drugs for repurposing in the treatment of progressive MS.
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Affiliation(s)
- Nick Cunniffe
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | | | - Debbie Ainslie
- Research Network, Multiple Sclerosis Society, London, UK
| | - David Baker
- Blizard Institute, Queen Mary University of London, London, UK
| | - Judy Beveridge
- Research Network, Multiple Sclerosis Society, London, UK
| | | | | | - Matthew Craner
- Department of Neurology, University of Oxford, Oxford, UK
| | - Denise Fitzgerald
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's Univeristy, Belfast, UK
| | - Alerie G de la Fuente
- Wellcome-Wolfson Institute for Experimental Medicine, Queen's Univeristy, Belfast, UK
| | | | - Emma Gray
- Multiple Sclerosis Society, London, UK
| | | | - Raj Kapoor
- Faculty of Brain Sciences, Queen Square Institute of Neurology, University College London, London, UK
| | - Ranjit Kaur
- Research Network, Multiple Sclerosis Society, London, UK
| | | | | | - Don Mahad
- Centre for Clinical Brain Sciences, Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, UK
| | - Björn Neumann
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Alan Palmer
- University of Reading, Reading, Berkshire, UK
| | | | - Stefano Pluchino
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | | | - Alan Rothaul
- Independent consultant, Woodstock, Oxfordshire, UK
| | | | - Kenneth J Smith
- Department of Neuroinflammation, Queen Square Institute of Neurology, University College London, London, UK
| | | | - Anna Williams
- MS Centre, Centre for regenerative medicine, University of Edinburgh, Edinburgh, UK
| | - Alasdair Coles
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
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Beutel T, Dzimiera J, Kapell H, Engelhardt M, Gass A, Schirmer L. Cortical projection neurons as a therapeutic target in multiple sclerosis. Expert Opin Ther Targets 2020; 24:1211-1224. [PMID: 33103501 DOI: 10.1080/14728222.2020.1842358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
INTRODUCTION Multiple sclerosis (MS) is a chronic inflammatory-demyelinating disease of the central nervous system associated with lesions of the cortical gray matter and subcortical white matter. Recently, cortical lesions have become a major focus of research because cortical pathology and neuronal damage are critical determinants of irreversible clinical progression. Recent transcriptomic studies point toward cell type-specific changes in cortical neurons in MS with a selective vulnerability of excitatory projection neuron subtypes. AREAS COVERED We discuss the cortical mapping and the molecular properties of excitatory projection neurons and their role in MS lesion pathology while placing an emphasis on their subtype-specific transcriptomic changes and levels of vulnerability. We also examine the latest magnetic resonance imaging techniques to study cortical MS pathology as a key tool for monitoring disease progression and treatment efficacy. Finally, we consider possible therapeutic avenues and novel strategies to protect excitatory cortical projection neurons. Literature search methodology: PubMed articles from 2000-2020. EXPERT OPINION Excitatory cortical projection neurons are an emerging therapeutic target in the treatment of progressive MS. Understanding neuron subtype-specific molecular pathologies and their exact spatial mapping will help establish starting points for the development of novel cell type-specific therapies and biomarkers in MS.
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Affiliation(s)
- Tatjana Beutel
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany
| | - Julia Dzimiera
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany
| | - Hannah Kapell
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany
| | - Maren Engelhardt
- Institute of Neuroanatomy, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
| | - Achim Gass
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany
| | - Lucas Schirmer
- Department of Neurology, Medical Faculty Mannheim, MCTN, Heidelberg University , Mannheim, Germany.,Interdisciplinary Center for Neurosciences, Heidelberg University , Heidelberg, Germany
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8
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Robinson RR, Dietz AK, Maroof AM, Asmis R, Forsthuber TG. The role of glial-neuronal metabolic cooperation in modulating progression of multiple sclerosis and neuropathic pain. Immunotherapy 2019; 11:129-147. [PMID: 30730270 DOI: 10.2217/imt-2018-0153] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
While the etiology of multiple sclerosis (MS) remains unclear, research from the clinic and preclinical models identified the essential role of inflammation and demyelination in the pathogenesis of MS. Current treatments focused on anti-inflammatory processes are effective against acute episodes and relapsing-remitting MS, but patients still move on to develop secondary progressive MS. MS progression is associated with activation of microglia and astrocytes, and importantly, metabolic dysfunction leading to neuronal death. Neuronal death also contributes to chronic neuropathic pain. Metabolic support of neurons by glia may play central roles in preventing progression of MS and chronic neuropathic pain. Here, we review mechanisms of metabolic cooperation between glia and neurons and outline future perspectives exploring metabolic support of neurons by glia.
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Affiliation(s)
- Rachel R Robinson
- Department of Biology, University of Texas at San Antonio, TX 78249, USA
| | - Alina K Dietz
- Department of Biology, University of Texas at San Antonio, TX 78249, USA
| | - Asif M Maroof
- Department of Biology, University of Texas at San Antonio, TX 78249, USA
| | - Reto Asmis
- Department of Internal Medicine, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, NC 27157, USA
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9
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Huhn K, Engelhorn T, Linker RA, Nagel AM. Potential of Sodium MRI as a Biomarker for Neurodegeneration and Neuroinflammation in Multiple Sclerosis. Front Neurol 2019; 10:84. [PMID: 30804885 PMCID: PMC6378293 DOI: 10.3389/fneur.2019.00084] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 01/22/2019] [Indexed: 01/18/2023] Open
Abstract
In multiple sclerosis (MS), experimental and ex vivo studies indicate that pathologic intra- and extracellular sodium accumulation may play a pivotal role in inflammatory as well as neurodegenerative processes. Yet, in vivo assessment of sodium in the microenvironment is hard to achieve. Here, sodium magnetic resonance imaging (23NaMRI) with its non-invasive properties offers a unique opportunity to further elucidate the effects of sodium disequilibrium in MS pathology in vivo in addition to regular proton based MRI. However, unfavorable physical properties and low in vivo concentrations of sodium ions resulting in low signal-to-noise-ratio (SNR) as well as low spatial resolution resulting in partial volume effects limited the application of 23NaMRI. With the recent advent of high-field MRI scanners and more sophisticated sodium MRI acquisition techniques enabling better resolution and higher SNR, 23NaMRI revived. These studies revealed pathologic total sodium concentrations in MS brains now even allowing for the (partial) differentiation of intra- and extracellular sodium accumulation. Within this review we (1) demonstrate the physical basis and imaging techniques of 23NaMRI and (2) analyze the present and future clinical application of 23NaMRI focusing on the field of MS thus highlighting its potential as biomarker for neuroinflammation and -degeneration.
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Affiliation(s)
- Konstantin Huhn
- Department of Neurology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
| | - Tobias Engelhorn
- Department of Neuroradiology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany
| | - Ralf A Linker
- Department of Neurology, University of Regensburg, Regensburg, Germany
| | - Armin M Nagel
- Department of Radiology, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany.,Division of Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany
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10
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Pappalardo LW, Samad OA, Liu S, Zwinger PJ, Black JA, Waxman SG. Nav1.5 in astrocytes plays a sex-specific role in clinical outcomes in a mouse model of multiple sclerosis. Glia 2018; 66:2174-2187. [PMID: 30194875 DOI: 10.1002/glia.23470] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Revised: 05/22/2018] [Accepted: 05/22/2018] [Indexed: 12/13/2022]
Abstract
Astrogliosis is a hallmark of neuroinflammatory disorders such as multiple sclerosis (MS). A detailed understanding of the underlying molecular mechanisms governing astrogliosis might facilitate the development of therapeutic targets. We investigated whether Nav1.5 expression in astrocytes plays a role in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a murine model of MS. We created a conditional knockout of Nav1.5 in astrocytes and determined whether this affects the clinical course of EAE, focal macrophage and T cell infiltration, and diffuse activation of astrocytes. We show that deletion of Nav1.5 from astrocytes leads to significantly worsened clinical outcomes in EAE, with increased inflammatory infiltrate in both early and late stages of disease, unexpectedly, in a sex-specific manner. Removal of Nav1.5 in astrocytes leads to increased inflammation in female mice with EAE, including increased astroglial response and infiltration of T cells and phagocytic monocytes. These cellular changes are consistent with more severe EAE clinical scores. Additionally, we found evidence suggesting possible dysregulation of the immune response-particularly with regard to infiltrating macrophages and activated microglia-in female Nav1.5 KO mice compared with WT littermate controls. Together, our results show that deletion of Nav1.5 from astrocytes leads to significantly worsened clinical outcomes in EAE, with increased inflammatory infiltrate in both early and late stages of disease, in a sex-specific manner.
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Affiliation(s)
- Laura W Pappalardo
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
| | - Omar A Samad
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
| | - Shujun Liu
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
| | - Pamela J Zwinger
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
| | - Joel A Black
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut, 06510.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut, 06516
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11
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Inglese M, Fleysher L, Oesingmann N, Petracca M. Clinical applications of ultra-high field magnetic resonance imaging in multiple sclerosis. Expert Rev Neurother 2018; 18:221-230. [PMID: 29369733 PMCID: PMC6300152 DOI: 10.1080/14737175.2018.1433033] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/23/2018] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Magnetic resonance imaging (MRI) is of paramount importance for the early diagnosis of multiple sclerosis (MS) and MRI findings are part of the MS diagnostic criteria. There is a growing interest in the use of ultra-high-field strength -7 Tesla- (7T) MRI to investigate, in vivo, the pathological substrate of the disease. Areas covered: An overview of 7T MRI applications in MS focusing on increased sensitivity for lesion detection, specificity of the central vein sign and better understanding of MS pathophysiology. Implications for disease diagnosis, monitoring and treatment planning are discussed. Expert commentary: 7T MRI provides increased signal-to-noise and contrast-to-noise-ratio that allow higher spatial resolution and better detection of anatomical and pathological features. The high spatial resolution reachable at 7T has been a game changer for neuroimaging applications not only in MS but also in epilepsy, brain tumors, dementia, and neuro-psychiatric disorders. Furthermore, the first 7T device has recently been cleared for clinical use by the food and drug administration.
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Affiliation(s)
- Matilde Inglese
- Department of Neurology, Icahn School of Medicine, Mount
Sinai, New York
- Radiology, Icahn School of Medicine, Mount Sinai, New
York
- Neuroscience, Icahn School of Medicine, Mount Sinai, New
York
| | - Lazar Fleysher
- Radiology, Icahn School of Medicine, Mount Sinai, New
York
| | | | - Maria Petracca
- Department of Neurology, Icahn School of Medicine, Mount
Sinai, New York
- Department of Neuroscience, Federico II University, Naples,
Italy
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12
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Ingwersen J, De Santi L, Wingerath B, Graf J, Koop B, Schneider R, Hecker C, Schröter F, Bayer M, Engelke AD, Dietrich M, Albrecht P, Hartung HP, Annunziata P, Aktas O, Prozorovski T. Nimodipine confers clinical improvement in two models of experimental autoimmune encephalomyelitis. J Neurochem 2018; 146:86-98. [PMID: 29473171 DOI: 10.1111/jnc.14324] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 02/07/2018] [Accepted: 02/08/2018] [Indexed: 12/31/2022]
Abstract
Multiple sclerosis is characterised by inflammatory neurodegeneration, with axonal injury and neuronal cell death occurring in parallel to demyelination. Regarding the molecular mechanisms responsible for demyelination and axonopathy, energy failure, aberrant expression of ion channels and excitotoxicity have been suggested to lead to Ca2+ overload and subsequent activation of calcium-dependent damage pathways. Thus, the inhibition of Ca2+ influx by pharmacological modulation of Ca2+ channels may represent a novel neuroprotective strategy in the treatment of secondary axonopathy. We therefore investigated the effects of the L-type voltage-gated calcium channel blocker nimodipine in two different models of mouse experimental autoimmune encephalomyelitis (EAE), an established experimental paradigm for multiple sclerosis. We show that preventive application of nimodipine (10 mg/kg per day) starting on the day of induction had ameliorating effects on EAE in SJL/J mice immunised with encephalitic myelin peptide PLP139-151 , specifically in late-stage disease. Furthermore, supporting these data, administration of nimodipine to MOG35-55 -immunised C57BL/6 mice starting at the peak of pre-established disease, also led to a significant decrease in disease score, indicating a protective effect on secondary CNS damage. Histological analysis confirmed that nimodipine attenuated demyelination, axonal loss and pathological axonal β-amyloid precursor protein accumulation in the cerebellum and spinal cord in the chronic phase of disease. Of note, we observed no effects of nimodipine on the peripheral immune response in EAE mice with regard to distribution, antigen-specific proliferation or activation patterns of lymphocytes. Taken together, our data suggest a CNS-specific effect of L-type voltage-gated calcium channel blockade to inflammation-induced neurodegeneration.
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Affiliation(s)
- Jens Ingwersen
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Lorenzo De Santi
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Britta Wingerath
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Jonas Graf
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Barbara Koop
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Reiner Schneider
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Christina Hecker
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Friederike Schröter
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Mary Bayer
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Anna Dorothee Engelke
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Michael Dietrich
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Philipp Albrecht
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Hans-Peter Hartung
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Pasquale Annunziata
- Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Orhan Aktas
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
| | - Tim Prozorovski
- Department of Neurology, Medical Faculty, Heinrich-Heine-University, Düsseldorf, Germany
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13
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Wang J, Ou SW, Wang YJ. Distribution and function of voltage-gated sodium channels in the nervous system. Channels (Austin) 2017; 11:534-554. [PMID: 28922053 DOI: 10.1080/19336950.2017.1380758] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are the basic ion channels for neuronal excitability, which are crucial for the resting potential and the generation and propagation of action potentials in neurons. To date, at least nine distinct sodium channel isoforms have been detected in the nervous system. Recent studies have identified that voltage-gated sodium channels not only play an essential role in the normal electrophysiological activities of neurons but also have a close relationship with neurological diseases. In this study, the latest research findings regarding the structure, type, distribution, and function of VGSCs in the nervous system and their relationship to neurological diseases, such as epilepsy, neuropathic pain, brain tumors, neural trauma, and multiple sclerosis, are reviewed in detail.
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Affiliation(s)
- Jun Wang
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
| | - Shao-Wu Ou
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
| | - Yun-Jie Wang
- a Department of Neurosurgery , The First Hospital of China Medical University , Shenyang , P.R. China
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14
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Abstract
Increasing evidence suggests a key role for tissue energy failure in the pathophysiology of multiple sclerosis (MS). Studies in experimental autoimmune encephalomyelitis (EAE), a commonly used model of MS, have been instrumental in illuminating the mechanisms that may be involved in compromising energy production. In this article, we review recent advances in EAE research focussing on factors that conspire to impair tissue energy metabolism, such as tissue hypoxia, mitochondrial dysfunction, production of reactive oxygen/nitrogen species, and sodium dysregulation, which are directly affected by energy insufficiency, and promote cellular damage. A greater understanding of how inflammation affects tissue energy balance may lead to novel and effective therapeutic strategies that ultimately will benefit not only people affected by MS but also people affected by the wide range of other neurological disorders in which neuroinflammation plays an important role.
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Affiliation(s)
- Roshni A Desai
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
| | - Kenneth J Smith
- Department of Neuroinflammation, UCL Institute of Neurology, London, UK
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15
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Pan S, Chan JR. Regulation and dysregulation of axon infrastructure by myelinating glia. J Cell Biol 2017; 216:3903-3916. [PMID: 29114067 PMCID: PMC5716274 DOI: 10.1083/jcb.201702150] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/06/2017] [Accepted: 10/18/2017] [Indexed: 12/21/2022] Open
Abstract
Pan and Chan discuss the role of myelinating glia in axonal development and the impact of demyelination on axon degeneration. Axon loss and neurodegeneration constitute clinically debilitating sequelae in demyelinating diseases such as multiple sclerosis, but the underlying mechanisms of secondary degeneration are not well understood. Myelinating glia play a fundamental role in promoting the maturation of the axon cytoskeleton, regulating axon trafficking parameters, and imposing architectural rearrangements such as the nodes of Ranvier and their associated molecular domains. In the setting of demyelination, these changes may be reversed or persist as maladaptive features, leading to axon degeneration. In this review, we consider recent insights into axon–glial interactions during development and disease to propose that disruption of the cytoskeleton, nodal architecture, and other components of axon infrastructure is a potential mediator of pathophysiological damage after demyelination.
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Affiliation(s)
- Simon Pan
- Department of Neurology, University of California, San Francisco, San Francisco, CA .,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA
| | - Jonah R Chan
- Department of Neurology, University of California, San Francisco, San Francisco, CA.,Neuroscience Graduate Program, University of California, San Francisco, San Francisco, CA
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16
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Doussau F, Dupont JL, Neel D, Schneider A, Poulain B, Bossu JL. Organotypic cultures of cerebellar slices as a model to investigate demyelinating disorders. Expert Opin Drug Discov 2017; 12:1011-1022. [PMID: 28712329 DOI: 10.1080/17460441.2017.1356285] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Demyelinating disorders, characterized by a chronic or episodic destruction of the myelin sheath, are a leading cause of neurological disability in young adults in western countries. Studying the complex mechanisms involved in axon myelination, demyelination and remyelination requires an experimental model preserving the neuronal networks and neuro-glial interactions. Organotypic cerebellar slice cultures appear to be the best alternative to in vivo experiments and the most commonly used model for investigating etiology or novel therapeutic strategies in multiple sclerosis. Areas covered: This review gives an overview of slice culture techniques and focuses on the use of organotypic cerebellar slice cultures on semi-permeable membranes for studying many aspects of axon myelination and cerebellar functions. Expert opinion: Cerebellar slice cultures are probably the easiest way to faithfully reproduce all stages of axon myelination/demyelination/remyelination in a three-dimensional neuronal network. However, in the cerebellum, neurological disability in multiple sclerosis also results from channelopathies which induce changes in Purkinje cell excitability. Cerebellar cultures offer easy access to electrophysiological approaches which are largely untapped and we believe that these cultures might be of great interest when studying changes in neuronal excitability, axonal conduction or synaptic properties that likely occur during multiple sclerosis.
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Affiliation(s)
- Frédéric Doussau
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Jean-Luc Dupont
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Dorine Neel
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Aline Schneider
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Bernard Poulain
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
| | - Jean Louis Bossu
- a Institut des Neurosciences Cellulaires et Intégratives, CNRS UPR 3212 , Université de Strasbourg , Strasbourg , France
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17
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Nandoskar A, Raffel J, Scalfari AS, Friede T, Nicholas RS. Pharmacological Approaches to the Management of Secondary Progressive Multiple Sclerosis. Drugs 2017; 77:885-910. [PMID: 28429241 DOI: 10.1007/s40265-017-0726-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
It is well recognised that the majority of the impact of multiple sclerosis (MS), both personal and societal, arises in the progressive phase where disability accumulates inexorably. As such, progressive MS (PMS) has been the target of pharmacological therapies for many years. However, there are no current licensed treatments for PMS. This stands in marked contrast to relapsing remitting MS (RRMS) where trials have resulted in numerous licensed therapies. PMS has proven to be a more difficult challenge compared to RRMS and this review focuses on secondary progressive MS (SPMS), where relapses occur before the onset of gradual, irreversible disability, and not primary progressive MS where disability accumulation occurs without prior relapses. Although there are similarities between the two forms, in both cases pinpointing when PMS starts is difficult in a condition in which disability can vary from day to day. There is also an overlap between the pathology of relapsing and progressive MS and this has contributed to the lack of well-defined outcomes, both surrogates and clinically relevant outcomes in PMS. In this review, we used the search term 'randomised controlled clinical drug trials in secondary progressive MS' in publications since 1988 together with recently completed trials where results were available. We found 34 trials involving 21 different molecules, of which 38% were successful in reaching their primary outcome. In general, the trials were well designed (e.g. double blind) with sample sizes ranging from 35 to 1949 subjects. The majority were parallel group, but there were also multi-arm and multidose trials as well as the more recent use of adaptive designs. The disability outcome most commonly used was the Expanded Disability Status Scale (EDSS) in all phases, but also magnetic resonance imaging (MRI)-measured brain atrophy has been utilised as a surrogate endpoint in phase II studies. The majority of the treatments tested in SPMS over the years were initially successful in RRMS. This has a number of implications in terms of targeting SPMS, but principally implies that the optimal strategy to target SPMS is to utilise the prodrome of relapses to initiate a therapy that will aim to both prevent progression and slow its accumulation. This approach is in agreement with the early targeting of MS but requires treatments that are both effective and safe if it is to be used before disability is a major problem. Recent successes will hopefully result in the first licensed therapy for PMS and enable us to test this approach.
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Affiliation(s)
- A Nandoskar
- Wolfson Neuroscience Laboratories, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, 160 Du Cane Road, London, W12 0NN, UK
| | - J Raffel
- Wolfson Neuroscience Laboratories, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, 160 Du Cane Road, London, W12 0NN, UK
| | - A S Scalfari
- Wolfson Neuroscience Laboratories, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, 160 Du Cane Road, London, W12 0NN, UK
| | - T Friede
- Department of Medical Statistics, University Medical Center Göttingen, Humboltallee 32, 37073, Göttingen, Germany
| | - R S Nicholas
- Wolfson Neuroscience Laboratories, Faculty of Medicine, Imperial College London, Hammersmith Hospital Campus, 160 Du Cane Road, London, W12 0NN, UK.
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18
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Correale J, Gaitán MI, Ysrraelit MC, Fiol MP. Progressive multiple sclerosis: from pathogenic mechanisms to treatment. Brain 2017; 140:527-546. [PMID: 27794524 DOI: 10.1093/brain/aww258] [Citation(s) in RCA: 201] [Impact Index Per Article: 28.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Accepted: 08/18/2016] [Indexed: 12/30/2022] Open
Abstract
During the past decades, better understanding of relapsing-remitting multiple sclerosis disease mechanisms have led to the development of several disease-modifying therapies, reducing relapse rates and severity, through immune system modulation or suppression. In contrast, current therapeutic options for progressive multiple sclerosis remain comparatively disappointing and challenging. One possible explanation is a lack of understanding of pathogenic mechanisms driving progressive multiple sclerosis. Furthermore, diagnosis is usually retrospective, based on history of gradual neurological worsening with or without occasional relapses, minor remissions or plateaus. In addition, imaging methods as well as biomarkers are not well established. Magnetic resonance imaging studies in progressive multiple sclerosis show decreased blood-brain barrier permeability, probably reflecting compartmentalization of inflammation behind a relatively intact blood-brain barrier. Interestingly, a spectrum of inflammatory cell types infiltrates the leptomeninges during subpial cortical demyelination. Indeed, recent magnetic resonance imaging studies show leptomeningeal contrast enhancement in subjects with progressive multiple sclerosis, possibly representing an in vivo marker of inflammation associated to subpial demyelination. Treatments for progressive disease depend on underlying mechanisms causing central nervous system damage. Immunity sheltered behind an intact blood-brain barrier, energy failure, and membrane channel dysfunction may be key processes in progressive disease. Interfering with these mechanisms may provide neuroprotection and prevent disability progression, while potentially restoring activity and conduction along damaged axons by repairing myelin. Although most previous clinical trials in progressive multiple sclerosis have yielded disappointing results, important lessons have been learnt, improving the design of novel ones. This review discusses mechanisms involved in progressive multiple sclerosis, correlations between histopathology and magnetic resonance imaging studies, along with possible new therapeutic approaches.
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19
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Zostawa J, Adamczyk J, Sowa P, Adamczyk-Sowa M. The influence of sodium on pathophysiology of multiple sclerosis. Neurol Sci 2017; 38:389-398. [PMID: 28078565 PMCID: PMC5331099 DOI: 10.1007/s10072-016-2802-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 12/19/2016] [Indexed: 01/06/2023]
Abstract
Multiple sclerosis (MS) is a chronic, inflammatory, autoimmune disease of the central nervous system, and is an important cause of disability in young adults. In genetically susceptible individuals, several environmental factors may play a partial role in the pathogenesis of MS. Some studies suggests that high-salt diet (>5 g/day) may contribute to the MS and other autoimmune disease development through the induction of pathogenic Th17 cells and pro-inflammatory cytokines in both humans and mice. However, the precise mechanisms of pro-inflammatory effect of sodium chloride intake are not yet explained. The purpose of this review was to discuss the present state of knowledge on the potential role of environmental and dietary factors, particularly sodium chloride on the development and course of MS.
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Affiliation(s)
- Jacek Zostawa
- Department of Neurology in Zabrze, Medical University of Silesia, ul. 3-go Maja 13-15, 41-800, Zabrze, Poland
| | - Jowita Adamczyk
- Department of Neurology in Zabrze, Medical University of Silesia, ul. 3-go Maja 13-15, 41-800, Zabrze, Poland.
| | - Paweł Sowa
- Department of Otorhinolaryngology and Oncological Laryngology, Medical University of Silesia, ul. C. Skłodowskiej 10, 41-800, Zabrze, Poland
| | - Monika Adamczyk-Sowa
- Department of Neurology in Zabrze, Medical University of Silesia, ul. 3-go Maja 13-15, 41-800, Zabrze, Poland
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20
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Schattling B, Fazeli W, Engeland B, Liu Y, Lerche H, Isbrandt D, Friese MA. Activity of Na V1.2 promotes neurodegeneration in an animal model of multiple sclerosis. JCI Insight 2016; 1:e89810. [PMID: 27882351 DOI: 10.1172/jci.insight.89810] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Counteracting the progressive neurological disability caused by neuronal and axonal loss is the major unmet clinical need in multiple sclerosis therapy. However, the mechanisms underlying irreversible neuroaxonal degeneration in multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE) are not well understood. A long-standing hypothesis holds that the distribution of voltage-gated sodium channels along demyelinated axons contributes to neurodegeneration by increasing neuroaxonal sodium influx and energy demand during CNS inflammation. Here, we tested this hypothesis in vivo by inserting a human gain-of-function mutation in the mouse NaV1.2-encoding gene Scn2a that is known to increase NaV1.2-mediated persistent sodium currents. In mutant mice, CNS inflammation during EAE leads to elevated neuroaxonal degeneration and increased disability and lethality compared with wild-type littermate controls. Importantly, immune cell infiltrates were not different between mutant EAE mice and wild-type EAE mice. Thus, this study shows that increased neuronal NaV1.2 activity exacerbates inflammation-induced neurodegeneration irrespective of immune cell alterations and identifies NaV1.2 as a promising neuroprotective drug target in multiple sclerosis.
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Affiliation(s)
- Benjamin Schattling
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
| | - Walid Fazeli
- Institut für Molekulare und Verhaltensneurowissenschaften, Universität zu Köln, Köln, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Bonn, Germany.,Klinik für Kinder- und Jugendmedizin, Uniklinik Köln, Köln, Germany
| | - Birgit Engeland
- Institut für Molekulare und Verhaltensneurowissenschaften, Universität zu Köln, Köln, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Bonn, Germany
| | - Yuanyuan Liu
- Abteilung Neurologie mit Schwerpunkt Epileptologie, Hertie-Institut für klinische Hirnforschung, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Holger Lerche
- Abteilung Neurologie mit Schwerpunkt Epileptologie, Hertie-Institut für klinische Hirnforschung, Universitätsklinikum Tübingen, Tübingen, Germany
| | - Dirk Isbrandt
- Institut für Molekulare und Verhaltensneurowissenschaften, Universität zu Köln, Köln, Germany.,Deutsches Zentrum für Neurodegenerative Erkrankungen, Bonn, Germany
| | - Manuel A Friese
- Institut für Neuroimmunologie und Multiple Sklerose, Universitätsklinikum Hamburg-Eppendorf, Hamburg, Germany
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21
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Wu H, Lu MH, Wang W, Zhang MY, Zhu QQ, Xia YY, Xu RX, Yang Y, Chen LH, Ma QH. Lamotrigine Reduces β-Site AβPP-Cleaving Enzyme 1 Protein Levels Through Induction of Autophagy. J Alzheimers Dis 2016; 46:863-76. [PMID: 25854934 DOI: 10.3233/jad-143162] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Lamotrigine (LTG), a broad-spectrum anti-epileptic drug widely used in treatment for seizures, shows potential efficacy in Alzheimer's disease (AD) therapy. Chronic LTG treatment rescues the suppressed long-term potentiation, loss of spines and cognitive deficits in AβPP/PS1 mice, known to overexpress a chimeric mouse/human mutant amyloid-β protein precursor (AβPP) and a mutant human presenilin 1 (PS1). These changes are accompanied by reduction of amyloid-β (Aβ) plaques density and of levels of β-C-terminal fragment of AβPP (β-CTF), a fragment of AβPP cleaved by β-secretase. These results suggest LTG treatment reduces Aβ production, possibly through modulation of cleavage of AβPP by β-secretase. However, the underlying mechanisms still remain unclear. In this study, decreased protein levels, but not mRNA levels of β-site AβPP-cleaving enzyme 1 (BACE1), were observed in cultured HEK293 cells and the brains of AβPP/PS1 transgenic mice upon LTG treatment. Moreover, LTG treatment suppressed mammalian target of rapamycin (mTOR) signaling, while enhancing activation of cAMP response element binding protein (CREB), two signaling pathways essential for autophagy induction. LTG treatment increased the numbers of LC3-GFP + puncta and LC3-II levels in HEK293 cells, indicating an induction of autophagy. The downregulation of BACE1 by LTG treatment was prevented by the autophagy inhibitor 3-Methyladenine. Therefore, this study shows that LTG treatment reduces the protein levels of BACE1 through activation of autophagy, possibly via inhibition of mTOR signaling and activation of CREB.
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Affiliation(s)
- Hao Wu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Mei-Hong Lu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Wang Wang
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Mao-Ying Zhang
- Affiliated Bayi Brain Hospital, Beijing Military Hospital, PLA and PhD Student Program of Southern Medical University, Beijing, China
| | - Qian-Qian Zhu
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Yi-Yuan Xia
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
| | - Ru-Xiang Xu
- Affiliated Bayi Brain Hospital, Beijing Military Hospital, PLA and PhD Student Program of Southern Medical University, Beijing, China
| | - Yi Yang
- Affiliated Bayi Brain Hospital, Beijing Military Hospital, PLA and PhD Student Program of Southern Medical University, Beijing, China
| | - Li-Hua Chen
- Affiliated Bayi Brain Hospital, Beijing Military Hospital, PLA and PhD Student Program of Southern Medical University, Beijing, China
| | - Quan-Hong Ma
- Jiangsu Key Laboratory of Translational Research and Therapy for Neuro-Psycho-Diseases and Institute of Neuroscience, Soochow University, Suzhou, Jiangsu, China
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22
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Bhise V, Dhib-Jalbut S. Further understanding of the immunopathology of multiple sclerosis: impact on future treatments. Expert Rev Clin Immunol 2016; 12:1069-89. [PMID: 27191526 DOI: 10.1080/1744666x.2016.1191351] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
INTRODUCTION The understanding of the immunopathogenesis of multiple sclerosis (MS) has expanded with more research into T-cell subtypes, cytokine contributors, B-cell participation, mitochondrial dysfunction, and more. Treatment options have rapidly expanded with three relatively recent oral therapy alternatives entering the arena. AREAS COVERED In the following review, we discuss current mechanisms of immune dysregulation in MS, how they relate to current treatments, and the impact these findings will have on the future of therapy. Expert commentary: The efficacy of these medications and understanding their mechanisms of actions validates the immunopathogenic mechanisms thought to underlie MS. Further research has exposed new targets, while new promising therapies have shed light on new aspects into the pathophysiology of MS.
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Affiliation(s)
- Vikram Bhise
- a Rutgers Biomedical and Health Sciences - Departments of Pediatrics , Robert Wood Johnson Medical School , New Brunswick , NJ , USA
| | - Suhayl Dhib-Jalbut
- b Rutgers Biomedical and Health Sciences - Departments of Neurology , Robert Wood Johnson Medical School , New Brunswick , NJ , USA
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23
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Sodium Channels, Mitochondria, and Axonal Degeneration in Peripheral Neuropathy. Trends Mol Med 2016; 22:377-390. [DOI: 10.1016/j.molmed.2016.03.008] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2016] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 12/19/2022]
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24
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Pappalardo LW, Black JA, Waxman SG. Sodium channels in astroglia and microglia. Glia 2016; 64:1628-45. [PMID: 26919466 DOI: 10.1002/glia.22967] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/27/2015] [Accepted: 01/04/2016] [Indexed: 12/19/2022]
Abstract
Voltage-gated sodium channels are required for electrogenesis in excitable cells. Their activation, triggered by membrane depolarization, generates transient sodium currents that initiate action potentials in neurons, cardiac, and skeletal muscle cells. Cells that have not traditionally been considered to be excitable (nonexcitable cells), including glial cells, also express sodium channels in physiological conditions as well as in pathological conditions. These channels contribute to multiple functional roles that are seemingly unrelated to the generation of action potentials. Here, we discuss the dynamics of sodium channel expression in astrocytes and microglia, and review evidence for noncanonical roles in effector functions of these cells including phagocytosis, migration, proliferation, ionic homeostasis, and secretion of chemokines/cytokines. We also examine possible mechanisms by which sodium channels contribute to the activity of glial cells, with an eye toward therapeutic implications for central nervous system disease. GLIA 2016;64:1628-1645.
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Affiliation(s)
- Laura W Pappalardo
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, CT
| | - Joel A Black
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, CT
| | - Stephen G Waxman
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, CT.,Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, CT
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Petracca M, Fleysher L, Oesingmann N, Inglese M. Sodium MRI of multiple sclerosis. NMR IN BIOMEDICINE 2016; 29:153-61. [PMID: 25851455 PMCID: PMC5771413 DOI: 10.1002/nbm.3289] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2014] [Revised: 02/25/2015] [Accepted: 02/26/2015] [Indexed: 05/11/2023]
Abstract
Multiple sclerosis (MS) is the most common cause of non-traumatic disability in young adults. The mechanisms underlying neurodegeneration and disease progression are poorly understood, in part as a result of the lack of non-invasive methods to measure and monitor neurodegeneration in vivo. Sodium MRI is a topic of increasing interest in MS research as it allows the metabolic characterization of brain tissue in vivo, and integration with the structural information provided by (1)H MRI, helping in the exploration of pathogenetic mechanisms and possibly offering insights into disease progression and monitoring of treatment outcomes. We present an up-to-date review of the sodium MRI application in MS organized into four main sections: (i) biological and pathogenetic role of sodium; (ii) brief overview of sodium imaging techniques; (iii) results of sodium MRI application in clinical studies; and (iv) future perspectives.
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Affiliation(s)
- Maria Petracca
- Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA
- Department of Neuroscience, Federico II University, Naples, Italy
| | - Lazar Fleysher
- Department of Radiology, Icahn School of Medicine, Mount Sinai, New York, USA
| | | | - Matilde Inglese
- Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA
- Department of Radiology, Icahn School of Medicine, Mount Sinai, New York, USA
- Department of Neuroscience, Icahn School of Medicine, Mount Sinai, New York, USA
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26
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Abstract
PURPOSE To evaluate longitudinal changes of visual function in relapsing-remitting multiple sclerosis (RRMS). METHODS Multifocal visual evoked potential (mfVEP), contrast sensitivity (CS), and Humphrey visual fields (HVFs) were obtained at two visits (mean follow-up, 1.5 [±0.9] years) in both eyes of 57 RRMS patients (53 eyes with optic neuritis [ON]: 14 ON within 6 months of first visit [ON < 6 months] and 39 ON ≥ 6 months; 57 non-ON). Longitudinal changes were assessed using mfVEP amplitude (log signal-to-noise ratio [logSNR]), latency, CS, and HVF mean deviation based on established 95% tolerance limits of test-retest variability. RESULTS A significant percentage of eyes in the ON < 6 months group exceeded 95% tolerance limits for mfVEP logSNR (21%, p < 0.05), latency (35%, p < 0.01), and CS (31% p < 0.001); more improved than worsened over time (14% vs. 7% for logSNR, 21% vs. 14% for latency, and 31% vs. 0% for CS). Multifocal visual evoked potential latency decreased in 11% of non-ON eyes and in 10% of eyes in the ON ≥ 6 months group, and increased in 21% and 10%, respectively (p < 0.01 for all). Latency changes correlated negatively with baseline latency (r = -0.43 and -0.45 for non-ON and ON ≥ 6 months; p = 0.0008). Although a nonsignificant percentage of non-ON and ON ≥ 6 months eyes exceeded tolerance limits for logSNR, CS, or HVF, logSNR and latency changes correlated, and both measures correlated with changes in CS (r = 0.47 to 0.79, p < 0.01). CONCLUSIONS Multifocal visual evoked potential, particularly latency, is potentially useful for assessing neuroprotective and remyelinating strategies in RRMS.
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Petracca M, Vancea RO, Fleysher L, Jonkman LE, Oesingmann N, Inglese M. Brain intra- and extracellular sodium concentration in multiple sclerosis: a 7 T MRI study. Brain 2016; 139:795-806. [PMID: 26792552 DOI: 10.1093/brain/awv386] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 11/08/2015] [Indexed: 12/31/2022] Open
Abstract
Intra-axonal accumulation of sodium ions is one of the key mechanisms of delayed neuro-axonal degeneration that contributes to disability accrual in multiple sclerosis. In vivo sodium magnetic resonance imaging studies have demonstrated an increase of brain total sodium concentration in patients with multiple sclerosis, especially in patients with greater disability. However, total sodium concentration is a weighted average of intra- and extra-cellular sodium concentration whose changes reflect different tissue pathophysiological processes. The in vivo, non-invasive measurement of intracellular sodium concentration is quite challenging and the few applications in patients with neurological diseases are limited to case reports and qualitative assessments. In the present study we provide first evidence of the feasibility of triple quantum filtered (23)Na magnetic resonance imaging at 7 T, and provide in vivo quantification of global and regional brain intra- and extra-cellular sodium concentration in 19 relapsing-remitting multiple sclerosis patients and 17 heathy controls. Global grey matter and white matter total sodium concentration (respectively P < 0.05 and P < 0.01), and intracellular sodium concentration (both P < 0.001) were higher while grey matter and white matter intracellular sodium volume fraction (indirect measure of extracellular sodium concentration) were lower (respectively P = 0.62 and P < 0.001) in patients compared with healthy controls. At a brain regional level, clusters of increased total sodium concentration and intracellular sodium concentration and decreased intracellular sodium volume fraction were found in several cortical, subcortical and white matter regions when patients were compared with healthy controls (P < 0.05 family-wise error corrected for total sodium concentration, P < 0.05 uncorrected for multiple comparisons for intracellular sodium concentration and intracellular sodium volume fraction). Measures of total sodium concentration and intracellular sodium volume fraction, but not measures of intracellular sodium concentration were correlated with T2-weighted and T1-weighted lesion volumes (0.05 < P < 0.01) and with Expanded Disability Status Scale (P < 0.05). Thus, suggesting that while intracellular sodium volume fraction decrease could reflect expansion of extracellular space due to tissue loss, intracellular sodium concentration increase could reflect neuro-axonal metabolic dysfunction.
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Affiliation(s)
- Maria Petracca
- 1 Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA 2 Department of Neuroscience, Reproductive and Odontostomatological Sciences, Federico II University, Naples, Italy
| | - Roxana O Vancea
- 1 Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA
| | - Lazar Fleysher
- 3 Department of Radiology, Icahn School of Medicine, Mount Sinai, New York, USA
| | - Laura E Jonkman
- 1 Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA 4 Department of Anatomy and Neurosciences, VU University Medical Center, Amsterdam, The Netherlands
| | | | - Matilde Inglese
- 1 Department of Neurology, Icahn School of Medicine, Mount Sinai, New York, USA 3 Department of Radiology, Icahn School of Medicine, Mount Sinai, New York, USA 6 Department of Neuroscience, Icahn School of Medicine, Mount Sinai, New York, USA 7 Department of Neuroscience, Rehabilitation, Ophthalmology, Genetics, Maternal and Child Health (DINOGMI), University of Genoa, Genoa, Italy
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28
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Sadeghian M, Mullali G, Pocock JM, Piers T, Roach A, Smith KJ. Neuroprotection by safinamide in the 6-hydroxydopamine model of Parkinson's disease. Neuropathol Appl Neurobiol 2015; 42:423-35. [PMID: 26300398 DOI: 10.1111/nan.12263] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2015] [Accepted: 08/11/2015] [Indexed: 02/02/2023]
Abstract
AIMS Current therapies in Parkinson's disease mainly treat symptoms rather than provide effective neuroprotection. We examined the effects of safinamide (monoamine oxidase B and sodium channel blocker) on microglial activation and the degeneration of dopaminergic neurons in a rat model of PD in vivo, and on microglia in vitro. METHODS Rats received unilateral stereotaxic injection of 6-hydroxydopamine into the medial forebrain bundle on day 0: The contralateral side served as control. Safinamide or vehicle was delivered from days 0 or 1, for 7 days, via sub-cutaneous mini-pumps. RESULTS In vehicle-treated rats 6-hydroxydopamine caused a significant increase in the number of activated MHC-II(+) microglia compared with the contralateral side, and only 50% of the dopaminergic neurons survived in the ipsilateral SNc. In contrast, rats treated daily with safinamide 50 and 150 mg/ml (on day 0 or 1) exhibited a significantly reduced number of activated microglia (55% reduction at 150 mg/ml) and a significant protection of dopaminergic neurons (80% of neurons survived) (P < 0.001) compared with vehicle-treated controls. Rasagiline, a monoamine oxidase B inhibitor, and lamotrigine, a sodium channel blocking drug, also protected dopaminergic neurons, indicating that safinamide may act by either or both mechanisms. Safinamide also reduced the activation of microglial cells in response to lipopolysaccharide exposure in vitro. CONCLUSION Safinamide therapy suppresses microglial activation and protects dopaminergic neurons from degeneration in the 6-hydroxydopamine model of PD, suggesting that the drug not only treats symptoms but also provides neuroprotection.
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Affiliation(s)
- Mona Sadeghian
- Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Institute of Neurology, London, UK
| | - Gizem Mullali
- Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Institute of Neurology, London, UK
| | - Jennifer M Pocock
- Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Institute of Neurology, London, UK
| | - Thomas Piers
- Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Institute of Neurology, London, UK
| | - Arthur Roach
- Parkinson's UK, London, UK.,Chord. Therapeutics, Geneva, Switzerland
| | - Kenneth J Smith
- Department of Neuroinflammation, Queen Square Multiple Sclerosis Centre, UCL Institute of Neurology, London, UK
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Dynamics of sodium channel Nav1.5 expression in astrocytes in mouse models of multiple sclerosis. Neuroreport 2015; 25:1208-15. [PMID: 25144393 DOI: 10.1097/wnr.0000000000000249] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Astrocytes actively participate in the response of the central nervous system to injury, including in multiple sclerosis. Astrocytes can play both beneficial and detrimental roles in response to neuroinflammation; however, in extreme cases, astrogliosis can result in the formation of a glial scar, which can impede the regeneration of injured neurons. Although astrocytes do not express the voltage-gated sodium channel Nav1.5 in the nonpathological human brain, they exhibit robust upregulation of Nav1.5 within acute and chronic multiple sclerosis lesions. Recent work has indicated that Nav1.5 contributes to the pathways that regulate glial scar formation in vitro through modulation of intracellular Ca levels. However, the temporal dynamics of astrocytic Nav1.5 channel expression in response to neuroinflammatory pathologies has not been investigated. We examined astrocytes from mice with monophasic and chronic-relapsing (CR) experimental autoimmune encephalomyelitis (EAE) by immunohistochemical analysis to determine whether Nav1.5 is expressed in these cells, and whether the expression correlates with the severity of disease and/or phases of relapse and remission. Our results demonstrate that Nav1.5 is upregulated in astrocytes in situ in a temporal manner that correlates with disease severity in both monophasic and CR EAE. Further, in CR EAE, Nav1.5 expression is upregulated during relapses and subsequently attenuated during periods of remission. These observations are consistent with the suggestion that Nav1.5 can play a role in the response of astrocytes to inflammatory pathologies in the central nervous system and suggest Nav1.5 may be a potential therapeutic target to modulate reactive astrogliosis in vivo.
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30
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Ellwardt E, Zipp F. Molecular mechanisms linking neuroinflammation and neurodegeneration in MS. Exp Neurol 2014; 262 Pt A:8-17. [DOI: 10.1016/j.expneurol.2014.02.006] [Citation(s) in RCA: 117] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Revised: 01/31/2014] [Accepted: 02/07/2014] [Indexed: 12/21/2022]
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31
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Liu S, Zwinger P, Black J, Waxman S. Tapered withdrawal of phenytoin removes protective effect in EAE without inflammatory rebound and mortality. J Neurol Sci 2014; 341:8-12. [DOI: 10.1016/j.jns.2014.03.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 11/29/2022]
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Pappalardo LW, Samad OA, Black JA, Waxman SG. Voltage-gated sodium channel Nav 1.5 contributes to astrogliosis in an in vitro model of glial injury via reverse Na+ /Ca2+ exchange. Glia 2014; 62:1162-75. [PMID: 24740847 DOI: 10.1002/glia.22671] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2013] [Revised: 03/25/2014] [Accepted: 03/27/2014] [Indexed: 12/19/2022]
Abstract
Astrogliosis is a prominent feature of many, if not all, pathologies of the brain and spinal cord, yet a detailed understanding of the underlying molecular pathways involved in the transformation from quiescent to reactive astrocyte remains elusive. We investigated the contribution of voltage-gated sodium channels to astrogliosis in an in vitro model of mechanical injury to astrocytes. Previous studies have shown that a scratch injury to astrocytes invokes dual mechanisms of migration and proliferation in these cells. Our results demonstrate that wound closure after mechanical injury, involving both migration and proliferation, is attenuated by pharmacological treatment with tetrodotoxin (TTX) and KB-R7943, at a dose that blocks reverse mode of the Na(+) /Ca(2+) exchanger (NCX), and by knockdown of Nav 1.5 mRNA. We also show that astrocytes display a robust [Ca(2+) ]i transient after mechanical injury and demonstrate that this [Ca(2+) ]i response is also attenuated by TTX, KB-R7943, and Nav 1.5 mRNA knockdown. Our results suggest that Nav 1.5 and NCX are potential targets for modulation of astrogliosis after injury via their effect on [Ca(2+) ]i .
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Affiliation(s)
- Laura W Pappalardo
- Department of Neurology and Center for Neuroscience and Regeneration Research, Yale University School of Medicine, New Haven, Connecticut; Rehabilitation Research Center, VA Connecticut Healthcare System, West Haven, Connecticut
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33
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Schattling B, Eggert B, Friese MA. Acquired channelopathies as contributors to development and progression of multiple sclerosis. Exp Neurol 2014; 262 Pt A:28-36. [PMID: 24656770 DOI: 10.1016/j.expneurol.2013.12.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 12/13/2013] [Indexed: 12/18/2022]
Abstract
Multiple sclerosis (MS), the most frequent inflammatory disease of the central nervous system (CNS), affects about two and a half million individuals worldwide and causes major burdens to the patients, which develop the disease usually at the age of 20 to 40. MS is likely referable to a breakdown of immune cell tolerance to CNS self-antigens resulting in focal immune cell infiltration, activation of microglia and astrocytes, demyelination and axonal and neuronal loss. Here we discuss how altered expression patterns and dysregulated functions of ion channels contribute on a molecular level to nearly all pathophysiological steps of the disease. In particular the detrimental redistribution of ion channels along axons, as well as neuronal excitotoxicity with regard to imbalanced glutamate homeostasis during chronic CNS inflammation will be discussed in detail. Together, we describe which ion channels in the immune and nervous system commend as attractive future drugable targets in MS treatment.
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Affiliation(s)
- Benjamin Schattling
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Britta Eggert
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany
| | - Manuel A Friese
- Zentrum für Molekulare Neurobiologie, Universitätsklinikum Hamburg-Eppendorf, Falkenried 94, D-20251 Hamburg, Germany.
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Abstract
Multiple sclerosis (MS) is the most frequent chronic inflammatory disease of the CNS, and imposes major burdens on young lives. Great progress has been made in understanding and moderating the acute inflammatory components of MS, but the pathophysiological mechanisms of the concomitant neurodegeneration--which causes irreversible disability--are still not understood. Chronic inflammatory processes that continuously disturb neuroaxonal homeostasis drive neurodegeneration, so the clinical outcome probably depends on the balance of stressor load (inflammation) and any remaining capacity for neuronal self-protection. Hence, suitable drugs that promote the latter state are sorely needed. With the aim of identifying potential novel therapeutic targets in MS, we review research on the pathological mechanisms of neuroaxonal dysfunction and injury, such as altered ion channel activity, and the endogenous neuroprotective pathways that counteract oxidative stress and mitochondrial dysfunction. We focus on mechanisms inherent to neurons and their axons, which are separable from those acting on inflammatory responses and might, therefore, represent bona fide neuroprotective drug targets with the capability to halt MS progression.
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35
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Lo A. Advancement of therapies for neuroprotection in multiple sclerosis. Expert Rev Neurother 2014; 8:1355-66. [DOI: 10.1586/14737175.8.9.1355] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Al-Izki S, Pryce G, Hankey DJR, Lidster K, von Kutzleben SM, Browne L, Clutterbuck L, Posada C, Edith Chan AW, Amor S, Perkins V, Gerritsen WH, Ummenthum K, Peferoen-Baert R, van der Valk P, Montoya A, Joel SP, Garthwaite J, Giovannoni G, Selwood DL, Baker D. Lesional-targeting of neuroprotection to the inflammatory penumbra in experimental multiple sclerosis. ACTA ACUST UNITED AC 2013; 137:92-108. [PMID: 24287115 DOI: 10.1093/brain/awt324] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Progressive multiple sclerosis is associated with metabolic failure of the axon and excitotoxicity that leads to chronic neurodegeneration. Global sodium-channel blockade causes side effects that can limit its use for neuroprotection in multiple sclerosis. Through selective targeting of drugs to lesions we aimed to improve the potential therapeutic window for treatment. This was assessed in the relapsing-progressive experimental autoimmune encephalomyelitis ABH mouse model of multiple sclerosis using conventional sodium channel blockers and a novel central nervous system-excluded sodium channel blocker (CFM6104) that was synthesized with properties that selectively target the inflammatory penumbra in experimental autoimmune encephalomyelitis lesions. Carbamazepine and oxcarbazepine were not immunosuppressive in lymphocyte-driven autoimmunity, but slowed the accumulation of disability in experimental autoimmune encephalomyelitis when administered during periods of the inflammatory penumbra after active lesion formation, and was shown to limit the development of neurodegeneration during optic neuritis in myelin-specific T cell receptor transgenic mice. CFM6104 was shown to be a state-selective, sodium channel blocker and a fluorescent p-glycoprotein substrate that was traceable. This compound was >90% excluded from the central nervous system in normal mice, but entered the central nervous system during the inflammatory phase in experimental autoimmune encephalomyelitis mice. This occurs after the focal and selective downregulation of endothelial p-glycoprotein at the blood-brain barrier that occurs in both experimental autoimmune encephalomyelitis and multiple sclerosis lesions. CFM6104 significantly slowed down the accumulation of disability and nerve loss in experimental autoimmune encephalomyelitis. Therapeutic-targeting of drugs to lesions may reduce the potential side effect profile of neuroprotective agents that can influence neurotransmission. This class of agents inhibit microglial activity and neural sodium loading, which are both thought to contribute to progressive neurodegeneration in multiple sclerosis and possibly other neurodegenerative diseases.
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Affiliation(s)
- Sarah Al-Izki
- 1 Neuroimmunology Unit, Blizard Institute, Barts and the London School of Medicine and Dentistry, Queen Mary University of London, London, UK
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Neuroprotection in a novel mouse model of multiple sclerosis. PLoS One 2013; 8:e79188. [PMID: 24223903 PMCID: PMC3817036 DOI: 10.1371/journal.pone.0079188] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 09/24/2013] [Indexed: 01/16/2023] Open
Abstract
Multiple sclerosis is an immune-mediated, demyelinating and neurodegenerative disease that currently lacks any neuroprotective treatments. Innovative neuroprotective trial designs are required to hasten the translational process of drug development. An ideal target to monitor the efficacy of strategies aimed at treating multiple sclerosis is the visual system, which is the most accessible part of the human central nervous system. A novel C57BL/6 mouse line was generated that expressed transgenes for a myelin oligodendrocyte glycoprotein-specific T cell receptor and a retinal ganglion cell restricted-Thy1 promoter-controlled cyan fluorescent protein. This model develops spontaneous or induced optic neuritis, in the absence of paralytic disease normally associated with most rodent autoimmune models of multiple sclerosis. Demyelination and neurodegeneration could be monitored longitudinally in the living animal using electrophysiology, visual sensitivity, confocal scanning laser ophthalmoscopy and optical coherence tomography all of which are relevant to human trials. This model offers many advantages, from a 3Rs, economic and scientific perspective, over classical experimental autoimmune encephalomyelitis models that are associated with substantial suffering of animals. Optic neuritis in this model led to inflammatory damage of axons in the optic nerve and subsequent loss of retinal ganglion cells in the retina. This was inhibited by the systemic administration of a sodium channel blocker (oxcarbazepine) or intraocular treatment with siRNA targeting caspase-2. These novel approaches have relevance to the future treatment of neurodegeneration of MS, which has so far evaded treatment.
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Abstract
Multiple sclerosis (MS) is a demyelinating disease of the central nervous system that is pathologically characterized by inflammatory demyelination and neurodegeneration. Axonal damage, along with neuronal loss, occurs from disease onset and may lead to progressive and permanent disability. In contrast with the inflammatory pathways, the molecular mechanisms leading to MS neurodegeneration remain largely elusive. With improved understanding of these mechanisms, new potential therapeutic targets for neuroprotection have emerged. We review the current understanding of neurodegenerative processes at play in MS and discuss potential outcome measures and targets for neuroprotection trials.
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Affiliation(s)
- Amir-Hadi Maghzi
- Multiple Sclerosis Center, Department of Neurology, University of California San Francisco (UCSF), 675 Nelson Rising Lane, 2nd floor, Room 221F, Box 3206, 94158, San Francisco, CA, USA,
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Alvarez S, Moldovan M, Krarup C. Prolonged high frequency electrical stimulation is lethal to motor axons of mice heterozygously deficient for the myelin protein P0 gene. Exp Neurol 2013; 247:552-61. [DOI: 10.1016/j.expneurol.2013.02.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 02/09/2013] [Accepted: 02/13/2013] [Indexed: 10/27/2022]
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40
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Stevens M, Timmermans S, Bottelbergs A, Hendriks JJ, Brône B, Baes M, Tytgat J. Block of a subset of sodium channels exacerbates experimental autoimmune encephalomyelitis. J Neuroimmunol 2013; 261:21-8. [DOI: 10.1016/j.jneuroim.2013.04.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 03/19/2013] [Accepted: 04/11/2013] [Indexed: 10/26/2022]
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Pérez-Medina C, Patel N, Robson M, Lythgoe MF, Årstad E. Synthesis and evaluation of a 125I-labeled iminodihydroquinoline-derived tracer for imaging of voltage-gated sodium channels. Bioorg Med Chem Lett 2013; 23:5170-3. [PMID: 23910595 PMCID: PMC3764405 DOI: 10.1016/j.bmcl.2013.07.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 07/10/2013] [Accepted: 07/11/2013] [Indexed: 12/04/2022]
Abstract
In vivo imaging of voltage-gated sodium channels (VGSCs) can potentially provide insights into the activation of neuronal pathways and aid the diagnosis of a number of neurological diseases. The iminodihydroquinoline WIN17317-3 is one of the most potent sodium channel blockers reported to date and binds with high affinity to VGSCs throughout the rat brain. We have synthesized a 125I-labeled analogue of WIN17317-3 and evaluated the potential of the tracer for imaging of VGSCs with SPECT. Automated patch clamp studies with CHO cells expressing the Nav1.2 isoform and displacement studies with [3H]BTX yielded comparable results for the non-radioactive iodinated iminodihydroquinoline and WIN17317-3. However, the 125I-labeled tracer was rapidly metabolized in vivo, and suffered from low brain uptake and high accumulation of radioactivity in the intestines. The results suggest that iminodihydroquinolines are poorly suited for tracer development.
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Affiliation(s)
- Carlos Pérez-Medina
- Department of Chemistry and Institute of Nuclear Medicine, UCL, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
| | - Niral Patel
- Department of Chemistry and Institute of Nuclear Medicine, UCL, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Centre for Advanced Biomedical Imaging, UCL, 72 Huntley Street, London WC1E 6BT, United Kingdom
| | - Mathew Robson
- UCL Cancer Institute, University College London, 72 Huntley Street, London WC1E 6BT, United Kingdom
| | - Mark F. Lythgoe
- Centre for Advanced Biomedical Imaging, UCL, 72 Huntley Street, London WC1E 6BT, United Kingdom
| | - Erik Årstad
- Department of Chemistry and Institute of Nuclear Medicine, UCL, 235 Euston Road (T-5), London NW1 2BU, United Kingdom
- Corresponding author. Tel./fax: +44 (0)02076792344.
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Inglese M, Oesingmann N, Zaaraoui W, Ranjeva JP, Fleysher L. Sodium imaging as a marker of tissue injury in patients with multiple sclerosis. Mult Scler Relat Disord 2013; 2:263-9. [PMID: 25877838 DOI: 10.1016/j.msard.2013.03.009] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 12/30/2022]
Abstract
Recent studies have suggested that intra-axonal sodium accumulation contribute to axonal degeneration in patients with MS. Advances in MRI hardware and software allow acquisition of brain sodium signal in vivo. This review begins with a summary of the experimental evidence for impairment of sodium homeostasis in MS. Then, MRI methods for sodium acquisition are reviewed and the application of the techniques in patients with MS is discussed. Sodium imaging and ultra-high field MRI have the potential to provide tissue-specific markers of neurodegeneration in MS.
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Affiliation(s)
- M Inglese
- Department of Neurology, Mount Sinai School of Medicine, NY, USA; Department of Radiology, Mount Sinai School of Medicine, NY, USA; Department of Neuroscience, Mount Sinai School of Medicine, NY, USA.
| | - N Oesingmann
- Siemens Medical Solutions USA, Inc., New York University, NY, USA
| | - W Zaaraoui
- CRMBM-CEMEREM, UMR 7339, CNRS, Aix-Marseille université, France; Siemens Medical Solutions USA, Inc., New York University, NY, USA
| | - J P Ranjeva
- CRMBM-CEMEREM, UMR 7339, CNRS, Aix-Marseille université, France; Siemens Medical Solutions USA, Inc., New York University, NY, USA
| | - L Fleysher
- Department of Radiology, Mount Sinai School of Medicine, NY, USA
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Morsali D, Bechtold D, Lee W, Chauhdry S, Palchaudhuri U, Hassoon P, Snell DM, Malpass K, Piers T, Pocock J, Roach A, Smith KJ. Safinamide and flecainide protect axons and reduce microglial activation in models of multiple sclerosis. ACTA ACUST UNITED AC 2013; 136:1067-82. [PMID: 23518709 DOI: 10.1093/brain/awt041] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Axonal degeneration is a major cause of permanent disability in the inflammatory demyelinating disease multiple sclerosis, but no therapies are known to be effective in axonal protection. Sodium channel blocking agents can provide effective protection of axons in the white matter in experimental models of multiple sclerosis, but the mechanism of action (directly on axons or indirectly via immune modulation) remains uncertain. Here we have examined the efficacy of two sodium channel blocking agents to protect white matter axons in two forms of experimental autoimmune encephalomyelitis, a common model of multiple sclerosis. Safinamide is currently in phase III development for use in Parkinson's disease based on its inhibition of monoamine oxidase B, but the drug is also a potent state-dependent inhibitor of sodium channels. Safinamide provided significant protection against neurological deficit and axonal degeneration in experimental autoimmune encephalomyelitis, even when administration was delayed until after the onset of neurological deficit. Protection of axons was associated with a significant reduction in the activation of microglia/macrophages within the central nervous system. To clarify which property of safinamide was likely to be involved in the suppression of the innate immune cells, the action of safinamide on microglia/macrophages was compared with that of the classical sodium channel blocking agent, flecainide, which has no recognized monoamine oxidase B activity, and which has previously been shown to protect the white matter in experimental autoimmune encephalomyelitis. Flecainide was also potent in suppressing microglial activation in experimental autoimmune encephalomyelitis. To distinguish whether the suppression of microglia was an indirect consequence of the reduction in axonal damage, or possibly instrumental in the axonal protection, the action of safinamide was examined in separate experiments in vitro. In cultured primary rat microglial cells activated by lipopolysaccharide, safinamide potently suppressed microglial superoxide production and enhanced the production of the anti-oxidant glutathione. The findings show that safinamide is effective in protecting axons from degeneration in experimental autoimmune encephalomyelitis, and that this effect is likely to involve a direct effect on microglia that can result in a less activated phenotype. Together, this work highlights the potential of safinamide as an effective neuroprotective agent in multiple sclerosis, and implicates microglia in the protective mechanism.
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Affiliation(s)
- Damineh Morsali
- Department of Neuroinflammation, UCL Institute of Neurology, Queen Square, 1 Wakefield Street, London, WC1N 1PJ, UK.
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Dell'Acqua ML, Lorenzini L, D'Intino G, Sivilia S, Pasqualetti P, Panetta V, Paradisi M, Filippi MM, Baiguera C, Pizzi M, Giardino L, Rossini PM, Calzà L. Functional and molecular evidence of myelin- and neuroprotection by thyroid hormone administration in experimental allergic encephalomyelitis. Neuropathol Appl Neurobiol 2012; 38:454-70. [PMID: 22007951 DOI: 10.1111/j.1365-2990.2011.01228.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
AIMS Recent data in mouse and rat demyelination models indicate that administration of thyroid hormone (TH) has a positive effect on the demyelination/remyelination balance. As axonal pathology has been recognized as an early neuropathological event in multiple sclerosis, and remyelination is considered a pre-eminent neuroprotective strategy, in this study we investigated whether TH administration improves nerve impulse propagation and protects axons. METHODS We followed up the somatosensory evoked potentials (SEPs) in triiodothyronine (T3)-treated and untreated experimental allergic encephalomyelitis (EAE) Dark-Agouti female rats during the electrical stimulation of the tail nerve. T3 treatment started on the 10th day post immunization (DPI) and a pulse administration was continued until the end of the study (33 DPI). SEPs were recorded at baseline (8 DPI) and the day after each hormone/ vehicle administration. RESULTS T3 treatment was associated with better outcome of clinical and neurophysiological parameters. SEPs latencies of the two groups behaved differently, being briefer and closer to control values (=faster impulse propagation) in T3-treated animals. The effect was evident on 24 DPI. In the same groups of animals, we also investigated axonal proteins, showing that T3 administration normalizes neurofilament immunoreactivity in the fasciculus gracilis and tau hyperphosphorylation in the lumbar spinal cord of EAE animals. No sign of plasma hyperthyroidism was found; moreover, the dysregulation of TH nuclear receptor expression observed in the spinal cord of EAE animals was corrected by T3 treatment. CONCLUSIONS T3 supplementation results in myelin sheath protection, nerve conduction preservation and axon protection in this animal model of multiple sclerosis.
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Affiliation(s)
- M L Dell'Acqua
- Department of Neurology, University Campus Bio-Medico, Rome, Italy
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Abstract
Multiple sclerosis (MS) is an inflammatory demyelinating disease that is considered by many people to have an autoimmune aetiology. In recent years, new data emerging from histopathology, imaging and other studies have expanded our understanding of the disease and may change the way in which it is treated. Conceptual shifts have included: first, an appreciation of the extent to which the neuron and its axon are affected in MS, and second, elucidation of how the neurobiology of axon-glial and, particularly, axon-myelin interaction may influence disease progression. In this article, we review advances in both areas, focusing on the molecular mechanisms underlying axonal loss in acute inflammation and in chronic demyelination, and discussing how the restoration of myelin sheaths via the regenerative process of remyelination might prevent axon degeneration. An understanding of these processes could lead to better strategies for the prevention and treatment of axonal loss, which will ultimately benefit patients with MS.
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Lassmann H, van Horssen J, Mahad D. Progressive multiple sclerosis: pathology and pathogenesis. Nat Rev Neurol 2012; 8:647-56. [PMID: 23007702 DOI: 10.1038/nrneurol.2012.168] [Citation(s) in RCA: 669] [Impact Index Per Article: 55.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Major progress has been made during the past three decades in understanding the inflammatory process and pathogenetic mechanisms in multiple sclerosis (MS). Consequently, effective anti-inflammatory and immunomodulatory treatments are now available for patients in the relapsing-remitting stage of the disease. This Review summarizes studies on the pathology of progressive MS and discusses new data on the mechanisms underlying its pathogenesis. In progressive MS, as in relapsing-remitting MS, active tissue injury is associated with inflammation, but the inflammatory response in the progressive phase occurs at least partly behind the blood-brain barrier, which makes it more difficult to treat. The other mechanisms that drive disease in patients with primary or secondary progressive MS are currently unresolved, although oxidative stress resulting in mitochondrial injury might participate in the induction of demyelination and neurodegeneration in both the relapsing-remitting and progressive stages of MS. Oxidative stress seems to be mainly driven by inflammation and oxidative burst in microglia; however, its effects might be amplified in patients with progressive MS by age-dependent iron accumulation in the brain and by mitochondrial gene deletions, triggered by the chronic inflammatory process.
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Affiliation(s)
- Hans Lassmann
- Centre for Brain Research, Medical University of Vienna, Wien, Austria.
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Black JA, Newcombe J, Waxman SG. Nav1.5 sodium channels in macrophages in multiple sclerosis lesions. Mult Scler 2012; 19:532-42. [PMID: 22951351 DOI: 10.1177/1352458512460417] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
BACKGROUND Macrophages are dynamic participants in destruction of white matter in active multiple sclerosis (MS) plaques. Regulation of phagocytosis and myelin degradation along endosomal pathways in macrophages is highly-orchestrated and critically-dependent upon acidification of endosomal lumena. Evidence from in vitro studies with macrophages and THP-1 cells suggests that sodium channel Nav1.5 is present in the limiting membrane of maturing endosomes where it plays a prominent role in the accumulation of protons. However, a contribution of the Nav1.5 channel to macrophage-mediated events in vivo has not been demonstrated. METHOD We examined macrophages within active MS lesions by immunohistochemistry to determine whether Nav1.5 is expressed in these cells in situ and, if expressed, whether it is localized to specific compartments along the endocytic pathway. RESULTS Our results demonstrate that Nav1.5 is expressed within macrophages in active MS lesions, and that it is preferentially expressed in late endosomes and phagolysosomes (Rab7(+), LAMP-1(+)), and sparsely expressed in early (EEA-1(+)) endosomes. Triple-immunolabeling studies showed localization of Nav1.5 within Rab7(+) endosomes containing proteolipid protein, a myelin marker, in macrophages within active MS plaques. CONCLUSIONS These observations support the suggestion that Nav1.5 contributes to the phagocytic pathway of myelin degradation in macrophages in vivo within MS lesions.
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Affiliation(s)
- Joel A Black
- Department of Neurology and Paralyzed Veterans of America Center for Neuroscience and Regeneration Research, Yale University School of Medicine, USA.
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Constantinescu CS, Farooqi N, O'Brien K, Gran B. Experimental autoimmune encephalomyelitis (EAE) as a model for multiple sclerosis (MS). Br J Pharmacol 2012; 164:1079-106. [PMID: 21371012 DOI: 10.1111/j.1476-5381.2011.01302.x] [Citation(s) in RCA: 979] [Impact Index Per Article: 81.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Experimental autoimmune encephalomyelitis (EAE) is the most commonly used experimental model for the human inflammatory demyelinating disease, multiple sclerosis (MS). EAE is a complex condition in which the interaction between a variety of immunopathological and neuropathological mechanisms leads to an approximation of the key pathological features of MS: inflammation, demyelination, axonal loss and gliosis. The counter-regulatory mechanisms of resolution of inflammation and remyelination also occur in EAE, which, therefore can also serve as a model for these processes. Moreover, EAE is often used as a model of cell-mediated organ-specific autoimmune conditions in general. EAE has a complex neuropharmacology, and many of the drugs that are in current or imminent use in MS have been developed, tested or validated on the basis of EAE studies. There is great heterogeneity in the susceptibility to the induction, the method of induction and the response to various immunological or neuropharmacological interventions, many of which are reviewed here. This makes EAE a very versatile system to use in translational neuro- and immunopharmacology, but the model needs to be tailored to the scientific question being asked. While creating difficulties and underscoring the inherent weaknesses of this model of MS in straightforward translation from EAE to the human disease, this variability also creates an opportunity to explore multiple facets of the immune and neural mechanisms of immune-mediated neuroinflammation and demyelination as well as intrinsic protective mechanisms. This allows the eventual development and preclinical testing of a wide range of potential therapeutic interventions.
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Affiliation(s)
- Cris S Constantinescu
- Division of Clinical Neurology, School of Clinical Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK.
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Campbell GR, Mahad DJ. Mitochondrial changes associated with demyelination: Consequences for axonal integrity. Mitochondrion 2012; 12:173-9. [DOI: 10.1016/j.mito.2011.03.007] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2010] [Revised: 02/04/2011] [Accepted: 03/04/2011] [Indexed: 12/30/2022]
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Ghaffarieh A, Levin LA. Optic nerve disease and axon pathophysiology. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2012. [PMID: 23206593 DOI: 10.1016/b978-0-12-398309-1.00002-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Optic neuropathy is the most common cause of irreversible blindness worldwide. Although the most common optic neuropathy is glaucoma, there are also many other optic neuropathies, for example, those associated with multiple sclerosis, giant cell arteritis, ischemia, and many other diseases. In almost all cases, the pathogenesis involves injury to the retinal ganglion cell axon, with consequent somal and axonal degeneration. This chapter reviews the clinical and pathophysiological properties associated with three of the most common optic neuropathies, as well as recent findings in understanding axonal degeneration. It concludes with a status report on therapies for optic nerve disease, including axoprotection, an approach being studied that has the goal of maintaining axonal integrity and function after injury.
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Affiliation(s)
- Alireza Ghaffarieh
- Department of Ophthalmology and Visual Sciences, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
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