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Sanabria-Castro A, Alape-Girón A, Flores-Díaz M, Echeverri-McCandless A, Parajeles-Vindas A. Oxidative stress involvement in the molecular pathogenesis and progression of multiple sclerosis: a literature review. Rev Neurosci 2024; 35:355-371. [PMID: 38163257 DOI: 10.1515/revneuro-2023-0091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/26/2023] [Indexed: 01/03/2024]
Abstract
Multiple sclerosis (MS) is an autoimmune debilitating disease of the central nervous system caused by a mosaic of interactions between genetic predisposition and environmental factors. The pathological hallmarks of MS are chronic inflammation, demyelination, and neurodegeneration. Oxidative stress, a state of imbalance between the production of reactive species and antioxidant defense mechanisms, is considered one of the key contributors in the pathophysiology of MS. This review is a comprehensive overview of the cellular and molecular mechanisms by which oxidant species contribute to the initiation and progression of MS including mitochondrial dysfunction, disruption of various signaling pathways, and autoimmune response activation. The detrimental effects of oxidative stress on neurons, oligodendrocytes, and astrocytes, as well as the role of oxidants in promoting and perpetuating inflammation, demyelination, and axonal damage, are discussed. Finally, this review also points out the therapeutic potential of various synthetic antioxidants that must be evaluated in clinical trials in patients with MS.
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Affiliation(s)
- Alfredo Sanabria-Castro
- Unidad de Investigación, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
- Departamento de Farmacología, Toxicología y Farmacodependencia, Facultad de Farmacia, Universidad de Costa Rica, San Pedro de Montes de Oca, 11501, Costa Rica
| | - Alberto Alape-Girón
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, Dulce Nombre Vázquez de Coronado, 11103, Costa Rica
| | - Marietta Flores-Díaz
- Instituto Clodomiro Picado, Facultad de Microbiología, Universidad de Costa Rica, Dulce Nombre Vázquez de Coronado, 11103, Costa Rica
| | - Ann Echeverri-McCandless
- Unidad de Investigación, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
| | - Alexander Parajeles-Vindas
- Servicio de Neurología, Hospital San Juan de Dios, Caja Costarricense de Seguro Social, San José, 10103, Costa Rica
- Servicio de Neurología, Hospital Clínica Bíblica, San José, 10104, Costa Rica
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2
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Preventing Axonal Sodium Overload or Mitochondrial Calcium Uptake Protects Axonal Mitochondria from Oxidative Stress-Induced Alterations. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2022; 2022:6125711. [PMID: 35663200 PMCID: PMC9157283 DOI: 10.1155/2022/6125711] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 05/02/2022] [Accepted: 05/05/2022] [Indexed: 11/26/2022]
Abstract
In neuroinflammatory and neurodegenerative disorders such as multiple sclerosis, mitochondrial damage caused by oxidative stress is believed to contribute to neuroaxonal damage. Previously, we demonstrated that exposure to hydrogen peroxide (H2O2) alters mitochondrial morphology and motility in myelinated axons and that these changes initiate at the nodes of Ranvier, where numerous sodium channels are located. Therefore, we suggested that mitochondrial damage may lead to ATP deficit, thereby affecting the efficiency of the sodium-potassium ATPase and eventually leading to sodium overload in axons. The increased intra-axonal sodium may revert the axonal sodium-calcium exchangers and thus may lead to a pathological calcium overload in the axoplasm and mitochondria. Here, we used the explanted murine ventral spinal roots to investigate whether modulation of sodium or calcium influx may prevent mitochondrial alterations in myelinated axons during exogenous application of H2O2 inducing oxidative stress. For that, tetrodotoxin, an inhibitor of voltage-gated sodium ion channels, and ruthenium 360, an inhibitor of the mitochondrial calcium uniporter, were applied simultaneously with hydrogen peroxide to axons. Mitochondrial shape and motility were analyzed. We showed that inhibition of axonal sodium influx prevented oxidative stress-induced morphological changes (i.e., increase in circularity and area and decrease in length) and preserved mitochondrial membrane potential, which is crucial for ATP production. Blocking mitochondrial calcium uptake prevented decrease in mitochondrial motility and also preserved membrane potential. Our findings indicate that alterations of both mitochondrial morphology and motility in the contexts of oxidative stress can be counterbalanced by modulating intramitochondrial ion concentrations pharmacologically. Moreover, motile mitochondria show preserved membrane potentials, pointing to a close association between mitochondrial motility and functionality.
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3
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Boscia F, Elkjaer ML, Illes Z, Kukley M. Altered Expression of Ion Channels in White Matter Lesions of Progressive Multiple Sclerosis: What Do We Know About Their Function? Front Cell Neurosci 2021; 15:685703. [PMID: 34276310 PMCID: PMC8282214 DOI: 10.3389/fncel.2021.685703] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/23/2021] [Indexed: 12/19/2022] Open
Abstract
Despite significant advances in our understanding of the pathophysiology of multiple sclerosis (MS), knowledge about contribution of individual ion channels to axonal impairment and remyelination failure in progressive MS remains incomplete. Ion channel families play a fundamental role in maintaining white matter (WM) integrity and in regulating WM activities in axons, interstitial neurons, glia, and vascular cells. Recently, transcriptomic studies have considerably increased insight into the gene expression changes that occur in diverse WM lesions and the gene expression fingerprint of specific WM cells associated with secondary progressive MS. Here, we review the ion channel genes encoding K+, Ca2+, Na+, and Cl- channels; ryanodine receptors; TRP channels; and others that are significantly and uniquely dysregulated in active, chronic active, inactive, remyelinating WM lesions, and normal-appearing WM of secondary progressive MS brain, based on recently published bulk and single-nuclei RNA-sequencing datasets. We discuss the current state of knowledge about the corresponding ion channels and their implication in the MS brain or in experimental models of MS. This comprehensive review suggests that the intense upregulation of voltage-gated Na+ channel genes in WM lesions with ongoing tissue damage may reflect the imbalance of Na+ homeostasis that is observed in progressive MS brain, while the upregulation of a large number of voltage-gated K+ channel genes may be linked to a protective response to limit neuronal excitability. In addition, the altered chloride homeostasis, revealed by the significant downregulation of voltage-gated Cl- channels in MS lesions, may contribute to an altered inhibitory neurotransmission and increased excitability.
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Affiliation(s)
- Francesca Boscia
- Division of Pharmacology, Department of Neuroscience, Reproductive and Dentistry Sciences, School of Medicine, University of Naples "Federico II", Naples, Italy
| | - Maria Louise Elkjaer
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
| | - Zsolt Illes
- Neurology Research Unit, Department of Clinical Research, University of Southern Denmark, Odense, Denmark.,Department of Neurobiology Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark.,Department of Neurology, Odense University Hospital, Odense, Denmark
| | - Maria Kukley
- Achucarro Basque Center for Neuroscience, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Bilbao, Spain
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Multiple Sclerosis-Associated hnRNPA1 Mutations Alter hnRNPA1 Dynamics and Influence Stress Granule Formation. Int J Mol Sci 2021; 22:ijms22062909. [PMID: 33809384 PMCID: PMC7998649 DOI: 10.3390/ijms22062909] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/04/2021] [Accepted: 03/09/2021] [Indexed: 12/21/2022] Open
Abstract
Evidence indicates that dysfunctional heterogeneous ribonucleoprotein A1 (hnRNPA1; A1) contributes to the pathogenesis of neurodegeneration in multiple sclerosis. Understanding molecular mechanisms of neurodegeneration in multiple sclerosis may result in novel therapies that attenuate neurodegeneration, thereby improving the lives of MS patients with multiple sclerosis. Using an in vitro, blue light induced, optogenetic protein expression system containing the optogene Cryptochrome 2 and a fluorescent mCherry reporter, we examined the effects of multiple sclerosis-associated somatic A1 mutations (P275S and F281L) in A1 localization, cluster kinetics and stress granule formation in real-time. We show that A1 mutations caused cytoplasmic mislocalization, and significantly altered the kinetics of A1 cluster formation/dissociation, and the quantity and size of clusters. A1 mutations also caused stress granule formation to occur more quickly and frequently in response to blue light stimulation. This study establishes a live cell optogenetics imaging system to probe localization and association characteristics of A1. It also demonstrates that somatic mutations in A1 alter its function and promote stress granule formation, which supports the hypothesis that A1 dysfunction may exacerbate neurodegeneration in multiple sclerosis.
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5
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Libner CD, Salapa HE, Levin MC. The Potential Contribution of Dysfunctional RNA-Binding Proteins to the Pathogenesis of Neurodegeneration in Multiple Sclerosis and Relevant Models. Int J Mol Sci 2020; 21:E4571. [PMID: 32604997 PMCID: PMC7369711 DOI: 10.3390/ijms21134571] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/19/2022] Open
Abstract
Neurodegeneration in multiple sclerosis (MS) is believed to underlie disease progression and permanent disability. Many mechanisms of neurodegeneration in MS have been proposed, such as mitochondrial dysfunction, oxidative stress, neuroinflammation, and RNA-binding protein dysfunction. The purpose of this review is to highlight mechanisms of neurodegeneration in MS and its models, with a focus on RNA-binding protein dysfunction. Studying RNA-binding protein dysfunction addresses a gap in our understanding of the pathogenesis of MS, which will allow for novel therapies to be generated to attenuate neurodegeneration before irreversible central nervous system damage occurs.
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Affiliation(s)
- Cole D. Libner
- Department of Health Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada;
- Office of Saskatchewan Multiple Sclerosis Clinical Research Chair, CMSNRC (Cameco MS Neuroscience. Research Center), University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada;
| | - Hannah E. Salapa
- Office of Saskatchewan Multiple Sclerosis Clinical Research Chair, CMSNRC (Cameco MS Neuroscience. Research Center), University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada;
- Department of Medicine, Neurology Division, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada
| | - Michael C. Levin
- Office of Saskatchewan Multiple Sclerosis Clinical Research Chair, CMSNRC (Cameco MS Neuroscience. Research Center), University of Saskatchewan, Saskatoon, SK S7K 0M7, Canada;
- Department of Medicine, Neurology Division, University of Saskatchewan, Saskatoon, SK S7N 5A2, Canada
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Abstract
Microglia dynamically interact with neurons influencing the development, structure, and function of neuronal networks. Recent studies suggest microglia may also influence neuronal activity by physically interacting with axonal domains responsible for action potential initiation and propagation. However, the nature of these microglial process interactions is not well understood. Microglial-axonal contacts are present early in development and persist through adulthood, implicating microglial interactions in the regulation of axonal integrity in both the developing and mature central nervous system. Moreover, changes in microglial-axonal contact have been described in disease states such as multiple sclerosis (MS) and traumatic brain injury (TBI). Depending on the disease state, there are increased associations with specific axonal segments. In MS, there is enhanced contact with the axon initial segment and node of Ranvier, while, in TBI, microglia alter interactions with axons at the site of injury, as well as at the axon initial segment. In this article, we review the interactions of microglial processes with axonal segments, analyzing their associations with various axonal domains and how these interactions may differ between MS and TBI. Furthermore, we discuss potential functional consequences and molecular mechanisms of these interactions and how these may differ among various types of microglial-axonal interactions.
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Affiliation(s)
- Savannah D Benusa
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Audrey D Lafrenaye
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, VA 23298, USA
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The Na +/Ca 2+ exchangers in demyelinating diseases. Cell Calcium 2019; 85:102130. [PMID: 31812115 DOI: 10.1016/j.ceca.2019.102130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Accepted: 11/20/2019] [Indexed: 12/15/2022]
Abstract
Intracellular [Na+]i and [Ca2+]i imbalance significantly contribute to neuro-axonal dysfunctions and maladaptive myelin repair or remyelination failure in chronic inflammatory demyelinating diseases such as multiple sclerosis. Progress in recent years has led to significant advances in understanding how [Ca2+]i signaling network drive degeneration or remyelination of demyelinated axons. The Na+/Ca2+ exchangers (NCXs), a transmembrane protein family including three members encoded by ncx1, ncx2, and ncx3 genes, are emerging important regulators of [Na+]i and [Ca2+]i both in neurons and glial cells. Here we review recent advance highlighting the role of NCX exchangers in axons and myelin-forming cells, i.e. oligodendrocytes, which represent the major targets of the aberrant inflammatory attack in multiple sclerosis. The contribution of NCX subtypes to axonal pathology and myelin synthesis will be discussed. Although a definitive understanding of mechanisms regulating axonal pathology and remyelination failure in chronic demyelinating diseases is still lacking and requires further investigation, current knowledge suggest that NCX activity plays a crucial role in these processes. Defining the relative contributions of each NCX transporter in axon pathology and myelinating glia will constitute not only a major advance in understanding in detail the intricate mechanism of neurodegeneration and remyelination failure in demyelinating diseases but also will help to identify neuroprotective or remyelinating strategies targeting selective NCX exchangers as a means of treating MS.
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8
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Oki S. Eomes-expressing T-helper cells as potential target of therapy in chronic neuroinflammation. Neurochem Int 2019; 130:104348. [DOI: 10.1016/j.neuint.2018.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2018] [Revised: 11/27/2018] [Accepted: 11/30/2018] [Indexed: 11/29/2022]
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9
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Baaklini CS, Rawji KS, Duncan GJ, Ho MFS, Plemel JR. Central Nervous System Remyelination: Roles of Glia and Innate Immune Cells. Front Mol Neurosci 2019; 12:225. [PMID: 31616249 PMCID: PMC6764409 DOI: 10.3389/fnmol.2019.00225] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Accepted: 09/04/2019] [Indexed: 12/31/2022] Open
Abstract
In diseases such as multiple sclerosis (MS), inflammation can injure the myelin sheath that surrounds axons, a process known as demyelination. The spontaneous regeneration of myelin, called remyelination, is associated with restoration of function and prevention of axonal degeneration. Boosting remyelination with therapeutic intervention is a promising new approach that is currently being tested in several clinical trials. The endogenous regulation of remyelination is highly dependent on the immune response. In this review article, we highlight the cell biology of remyelination and its regulation by innate immune cells. For the purpose of this review, we discuss the roles of microglia, and also astrocytes and oligodendrocyte progenitor cells (OPCs) as they are being increasingly recognized to have immune cell functions.
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Affiliation(s)
- Charbel S. Baaklini
- Department of Medicine, Division of Neurology, Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Khalil S. Rawji
- Wellcome Trust-Medical Research Council, Cambridge Stem Cell Institute, Cambridge Biomedical Campus, University of Cambridge, Cambridge, United Kingdom
| | - Greg J. Duncan
- Department of Neurology, Jungers Center for Neurosciences Research, Oregon Health and Science University, Portland, OR, United States
| | - Madelene F. S. Ho
- Department of Medicine, Division of Neurology, Neuroscience and Mental Health Institute, Faculty of Medicine & Dentistry, University of Alberta, Edmonton, AB, Canada
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10
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Song S, Luo L, Sun B, Sun D. Roles of glial ion transporters in brain diseases. Glia 2019; 68:472-494. [PMID: 31418931 DOI: 10.1002/glia.23699] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 07/22/2019] [Accepted: 07/26/2019] [Indexed: 12/21/2022]
Abstract
Glial ion transporters are important in regulation of ionic homeostasis, cell volume, and cellular signal transduction under physiological conditions of the central nervous system (CNS). In response to acute or chronic brain injuries, these ion transporters can be activated and differentially regulate glial functions, which has subsequent impact on brain injury or tissue repair and functional recovery. In this review, we summarized the current knowledge about major glial ion transporters, including Na+ /H+ exchangers (NHE), Na+ /Ca2+ exchangers (NCX), Na+ -K+ -Cl- cotransporters (NKCC), and Na+ -HCO3 - cotransporters (NBC). In acute neurological diseases, such as ischemic stroke and traumatic brain injury (TBI), these ion transporters are rapidly activated and play significant roles in regulation of the intra- and extracellular pH, Na+ , K+ , and Ca2+ homeostasis, synaptic plasticity, and myelin formation. However, overstimulation of these ion transporters can contribute to glial apoptosis, demyelination, inflammation, and excitotoxicity. In chronic brain diseases, such as glioma, Alzheimer's disease (AD), Parkinson's disease (PD), and multiple sclerosis (MS), glial ion transporters are involved in the glioma Warburg effect, glial activation, neuroinflammation, and neuronal damages. These findings suggest that glial ion transporters are involved in tissue structural and functional restoration, or brain injury and neurological disease development and progression. A better understanding of these ion transporters in acute and chronic neurological diseases will provide insights for their potential as therapeutic targets.
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Affiliation(s)
- Shanshan Song
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Lanxin Luo
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania.,School of Traditional Chinese Materia Medica, Shenyang Pharmaceutical University, Shenyang, China.,School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, China
| | - Baoshan Sun
- School of Functional Food and Wine, Shenyang Pharmaceutical University, Shenyang, China.,Pólo Dois Portos, Instituto National de Investigação Agrária e Veterinária, Dois Portos, Portugal
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, Pennsylvania.,Pittsburgh Institute for Neurodegenerative Disorders, University of Pittsburgh, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, Pennsylvania
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11
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Bastakis GG, Ktena N, Karagogeos D, Savvaki M. Models and treatments for traumatic optic neuropathy and demyelinating optic neuritis. Dev Neurobiol 2019; 79:819-836. [PMID: 31297983 DOI: 10.1002/dneu.22710] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 07/04/2019] [Accepted: 07/05/2019] [Indexed: 02/06/2023]
Abstract
Pathologies of the optic nerve could result as primary insults in the visual tract or as secondary deficits due to inflammation, demyelination, or compressing effects of the surrounding tissue. The extent of damage may vary from mild to severe, differently affecting patient vision, with the most severe forms leading to complete uni- or bilateral visual loss. The aim of researchers and clinicians in the field is to alleviate the symptoms of these, yet uncurable pathologies, taking advantage of known and novel potential therapeutic approaches, alone or in combinations, and applying them in a limited time window after the insult. In this review, we discuss the epidemiological and clinical profile as well as the pathophysiological mechanisms of two main categories of optic nerve pathologies, namely traumatic optic neuropathy and optic neuritis, focusing on the demyelinating form of the latter. Moreover, we report on the main rodent models mimicking these pathologies or some of their clinical aspects. The current treatment options will also be reviewed and novel approaches will be discussed.
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Affiliation(s)
| | - Niki Ktena
- University of Crete Faculty of Medicine, Heraklion, Greece.,Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Domna Karagogeos
- University of Crete Faculty of Medicine, Heraklion, Greece.,Institute of Molecular Biology and Biotechnology, Heraklion, Greece
| | - Maria Savvaki
- University of Crete Faculty of Medicine, Heraklion, Greece.,Institute of Molecular Biology and Biotechnology, Heraklion, Greece
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12
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Chatterjee M, Koel-Simmelink MJ, Verberk IM, Killestein J, Vrenken H, Enzinger C, Ropele S, Fazekas F, Khalil M, Teunissen CE. Contactin-1 and contactin-2 in cerebrospinal fluid as potential biomarkers for axonal domain dysfunction in multiple sclerosis. Mult Scler J Exp Transl Clin 2018; 4:2055217318819535. [PMID: 30627437 PMCID: PMC6305953 DOI: 10.1177/2055217318819535] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/31/2018] [Accepted: 11/22/2018] [Indexed: 01/06/2023] Open
Abstract
Background Contactin-1 and contactin-2 are important for the maintenance of axonal integrity. Objective To investigate the cerebrospinal fluid levels of contactin-1 and contactin-2 in multiple sclerosis patients and controls, and their potential use as prognostic markers for neurodegeneration. Methods Cerebrospinal fluid contactin-1 and contactin-2 were measured in relapsing–remitting multiple sclerosis (n = 41), secondary progressive multiple sclerosis (n = 26) and primary progressive multiple sclerosis patients (n = 13) and controls (n = 18), and in a second cohort with clinically isolated syndrome patients (n = 88, median clinical follow-up period of 2.3 years) and controls (n = 20). Correlations/linear regressions were analysed with other baseline cerebrospinal fluid axonal damage markers and cross-sectional/longitudinal magnetic resonance imaging features. Results Contactin-1 and contactin-2 levels were up to 1.4-fold reduced in relapsing–remitting multiple sclerosis (contactin-1: p = 0.01, contactin-2: p = 0.02) and secondary progressive multiple sclerosis (contactin-1: p = 0.05, contactin-2: p = 0.02) compared to controls. In clinically isolated syndrome patients, contactin-1 tended to increase when compared to controls (p = 0.07). Both contactin-1 and contactin-2 correlated with neurofilament light, neurofilament heavy and magnetic resonance imaging metrics differently depending on the disease stage. In clinically isolated syndrome patients, baseline contactin-2 level (β = –0.42, p = 0.04) predicted the longitudinal decline in cortex volume. Conclusion Cerebrospinal fluid contactin-1 and contactin-2 reveal axonal dysfunction in various stages of multiple sclerosis and their inclusion to the biomarker panel may provide better insight into the extent of axonal damage/dysfunction.
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Affiliation(s)
- Madhurima Chatterjee
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Marleen Ja Koel-Simmelink
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Inge Mw Verberk
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Joep Killestein
- Department of Neurology, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
| | - Hugo Vrenken
- Department of Radiology, VU University Medical Center, Amsterdam UMC, The Netherlands
| | | | - Stefan Ropele
- Department of Neurology, Medical University of Graz, Austria
| | - Franz Fazekas
- Department of Neurology, Medical University of Graz, Austria
| | - Michael Khalil
- Department of Neurology, Medical University of Graz, Austria
| | - Charlotte E Teunissen
- Neurochemistry Laboratory, Department of Clinical Chemistry, Amsterdam Neuroscience, VU University Medical Center, Amsterdam UMC, The Netherlands
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13
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Bode K, O'Halloran DM. NCX-DB: a unified resource for integrative analysis of the sodium calcium exchanger super-family. BMC Neurosci 2018; 19:19. [PMID: 29649983 PMCID: PMC5898058 DOI: 10.1186/s12868-018-0423-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Accepted: 03/28/2018] [Indexed: 12/20/2022] Open
Abstract
Na+/Ca2+ exchangers are low-affinity high-capacity transporters that mediate Ca2+ extrusion by coupling Ca2+ efflux to the influx of Na+ ions. The Na+/Ca2+ exchangers form a super-family comprised of three branches each differing in ion-substrate selectivity: Na+/Ca2+ exchangers (NCX), Na+/Ca2+/K+ exchangers, and Ca2+/cation exchangers. Their primary function is to maintain Ca2+ homeostasis and play a particularly important role in excitable cells that experience transient Ca2+ fluxes. Research into the role and activity of Na+/Ca2+ exchangers has focused extensively on the cardio-vascular system, however, growing evidence suggests that Na+/Ca2+ exchangers play a key role in neuronal processes such as memory formation, learning, oligodendrocyte differentiation, neuroprotection during brain ischemia and axon guidance. They have also been implicated in pathologies such as Alzheimer’s disease, Parkinson’s disease, Multiple Sclerosis and Epilepsy, however, a clear understanding of their mechanism during disease is lacking. To date, there has never been a central resource or database for Na+/Ca2+ exchangers. With clear disease relevance and ever-increasing research on Na+/Ca2+ exchangers from both model and non-model species, a database that unifies the data on Na+/Ca2+ exchangers is needed for future research. NCX-DB is a publicly available database with a web interface that enables users to explore various Na+/Ca2+ exchangers, perform cross-species sequence comparison, identify new exchangers, and stay-up to date with recent literature. NCX-DB is available on the web via an interactive user interface with an intuitive design, which is applicable for the identification and comparison of Na+/Ca2+ exchanger proteins across diverse species.
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Affiliation(s)
- Katrin Bode
- Department of Biological Sciences, The George Washington University, Science and Engineering Hall 6000, 800 22nd St. N.W., Washington, DC, 20052, USA.,Institute for Neuroscience, The George Washington University, 636A Ross Hall, 2300 I St. N.W., Washington, DC, 20052, USA
| | - Damien M O'Halloran
- Department of Biological Sciences, The George Washington University, Science and Engineering Hall 6000, 800 22nd St. N.W., Washington, DC, 20052, USA. .,Institute for Neuroscience, The George Washington University, 636A Ross Hall, 2300 I St. N.W., Washington, DC, 20052, USA.
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14
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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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Plemel JR, Liu WQ, Yong VW. Remyelination therapies: a new direction and challenge in multiple sclerosis. Nat Rev Drug Discov 2017; 16:617-634. [PMID: 28685761 DOI: 10.1038/nrd.2017.115] [Citation(s) in RCA: 181] [Impact Index Per Article: 25.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Multiple sclerosis is characterized by inflammatory activity that results in destruction of the myelin sheaths that enwrap axons. The currently available medications for multiple sclerosis are predominantly immune-modulating and do not directly promote repair. White matter regeneration, or remyelination, is a new and exciting potential approach to treating multiple sclerosis, as remyelination repairs the damaged regions of the central nervous system. A wealth of new strategies in animal models that promote remyelination, including the repopulation of oligodendrocytes that produce myelin, has led to several clinical trials to test new reparative therapies. In this Review, we highlight the biology of, and obstacles to, remyelination. We address new strategies to improve remyelination in preclinical models, highlight the therapies that are currently undergoing clinical trials and discuss the challenges of objectively measuring remyelination in trials of repair in multiple sclerosis.
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Affiliation(s)
- Jason R Plemel
- Hotchkiss Brain Institute and the Departments of Clinical Neurosciences and Oncology, University of Calgary, 3330 Hospital Drive, Calgary, Alberta T2N 4N1, Canada
| | - Wei-Qiao Liu
- Hotchkiss Brain Institute and the Departments of Clinical Neurosciences and Oncology, University of Calgary, 3330 Hospital Drive, Calgary, Alberta T2N 4N1, Canada
| | - V Wee Yong
- Hotchkiss Brain Institute and the Departments of Clinical Neurosciences and Oncology, University of Calgary, 3330 Hospital Drive, Calgary, Alberta T2N 4N1, Canada
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17
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Salapa HE, Lee S, Shin Y, Levin MC. Contribution of the Degeneration of the Neuro-Axonal Unit to the Pathogenesis of Multiple Sclerosis. Brain Sci 2017; 7:E69. [PMID: 28629158 PMCID: PMC5483642 DOI: 10.3390/brainsci7060069] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/09/2017] [Accepted: 06/14/2017] [Indexed: 11/17/2022] Open
Abstract
Multiple sclerosis (MS) is a demyelinating, autoimmune disease of the central nervous system. In recent years, it has become more evident that neurodegeneration, including neuronal damage and axonal injury, underlies permanent disability in MS. This manuscript reviews some of the mechanisms that could be responsible for neurodegeneration and axonal damage in MS and highlights the potential role that dysfunctional heterogeneous nuclear ribonucleoprotein A1 (hnRNP A1) and antibodies to hnRNP A1 may play in MS pathogenesis.
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Affiliation(s)
- Hannah E Salapa
- Department of Anatomy and Cell Biology, CMSNRC (Cameco MS Neuroscience Research Center), University of Saskatchewan, Saskatoon, SK S7N0Z1, Canada.
| | - Sangmin Lee
- Veterans Administration Medical Center, Memphis, TN 38104, USA.
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38104, USA.
| | - Yoojin Shin
- Veterans Administration Medical Center, Memphis, TN 38104, USA.
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38104, USA.
| | - Michael C Levin
- Department of Anatomy and Cell Biology, CMSNRC (Cameco MS Neuroscience Research Center), University of Saskatchewan, Saskatoon, SK S7N0Z1, Canada.
- Veterans Administration Medical Center, Memphis, TN 38104, USA.
- Department of Neurology, University of Tennessee Health Science Center, Memphis, TN 38104, USA.
- Department of Neurology, University of Saskatchewan, Saskatoon, SK S7N0Z1, Canada.
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18
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Liang W, Zhang W, Zhao S, Liang H, Zhang J, Wang L. Alterations of Caspr2 and Nav1.6 on myelinated axon damage in a rat model of chronic cerebral hypoperfusion. Exp Ther Med 2017; 13:2468-2472. [PMID: 28565865 PMCID: PMC5443296 DOI: 10.3892/etm.2017.4228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 01/11/2017] [Indexed: 11/19/2022] Open
Abstract
Myelinated axons require the correct localization of key proteins that are essential for nerve conduction and cognitive function. Little is known regarding the altered expression of contactin-associated protein 2 (Caspr2) at the juxtaparanodal regions and Nav1.6 at the node of Ranvier in response to chronic cerebral hypoperfusion (CCH). The aim of the present study was to examine the alterations in the key protein of myelinated axons and the potential mechanisms that may follow CCH. We established a rat model of CCH by controllable partial narrowing of bilateral common carotid arteries. Then, we detected cerebral blood flow (CBF) after surgery. We also evaluated motor-evoked potentials (MEPs), assessed the Morris water maze test, analyzed Caspr2 expression through immunohistochemistry and Nav1.6 protein expression through western blot analysis at 2, 4 and 12 weeks. The results revealed that the mean CBF value was significantly decreased to 33.90±5.48%. The MEP latencies and the escaping latencies were significantly prolonged. There was also an elongation of the first time passing of the hidden platform with a reduction of crossing platform times in spatial probing. Furthermore, the Caspr2 immunoreactivity demonstrated that the Caspr2 level was significantly downregulated with abnormal locations in the corpus callosum. The western blot analysis of Nav1.6 protein revealed that the level was reduced significantly over time. The results demonstrate that CCH leads to central conductive function loss, cognitive function damage and alterations in the key protein of myelinated axons, which may provide a molecular basis and key link for white matter damage.
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Affiliation(s)
- Weihua Liang
- No. 263 Clinic of PLA Army General Hospital, Beijing 101149, P.R. China.,Department of Neurology, Xinqiao Hospital, The Third Military Medical University, Chongqing 400038, P.R. China
| | - Weiwei Zhang
- PLA Army General Hospital, Beijing 100700, P.R. China
| | - Shifu Zhao
- Department of Neurology, Xinqiao Hospital, The Third Military Medical University, Chongqing 400038, P.R. China
| | - Hua Liang
- The 66083rd of PLA, Beijing 102488, P.R. China
| | - Jinli Zhang
- No. 263 Clinic of PLA Army General Hospital, Beijing 101149, P.R. China
| | - Luyan Wang
- No. 263 Clinic of PLA Army General Hospital, Beijing 101149, P.R. China
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19
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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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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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Biller A, Pflugmann I, Badde S, Diem R, Wildemann B, Nagel AM, Jordan J, Benkhedah N, Kleesiek J. Sodium MRI in Multiple Sclerosis is Compatible with Intracellular Sodium Accumulation and Inflammation-Induced Hyper-Cellularity of Acute Brain Lesions. Sci Rep 2016; 6:31269. [PMID: 27507776 PMCID: PMC4978993 DOI: 10.1038/srep31269] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Accepted: 07/18/2016] [Indexed: 12/25/2022] Open
Abstract
The cascade of inflammatory pathogenetic mechanisms in multiple sclerosis (MS) has no specific conventional MRI correlates. Clinicians therefore stipulate improved imaging specificity to define the pathological substrates of MS in vivo including mapping of intracellular sodium accumulation. Based upon preclinical findings and results of previous sodium MRI studies in MS patients we hypothesized that the fluid-attenuated sodium signal differs between acute and chronic lesions. We acquired brain sodium and proton MRI data of N = 29 MS patients; lesion type was defined by the presence or absence of contrast enhancement. N = 302 MS brain lesions were detected, and generalized linear mixed models were applied to predict lesion type based on sodium signals; thereby controlling for varying numbers of lesions among patients and confounding variables such as age and medication. Hierarchical model comparisons revealed that both sodium signals average tissue (χ2(1) = 27.89, p < 0.001) and fluid-attenuated (χ2(1) = 5.76, p = 0.016) improved lesion type classification. Sodium MRI signals were significantly elevated in acute compared to chronic lesions compatible with intracellular sodium accumulation in acute MS lesions. If confirmed in further studies, sodium MRI could serve as biomarker for diagnostic assessment of MS, and as readout parameter in clinical trials promoting attenuation of chronic inflammation.
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Affiliation(s)
- Armin Biller
- Multi-Dimensional Medical Imaging Lab, Department of Neuroradiology, University of Heidelberg, 69120 Heidelberg, Germany.,Department of Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany
| | - Isabella Pflugmann
- Multi-Dimensional Medical Imaging Lab, Department of Neuroradiology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Stephanie Badde
- Department of Biological Psychology and Neuropsychology, University of Hamburg, 20146 Hamburg, Germany.,Department of Psychology, New York University, New York, NY 10003, USA
| | - Ricarda Diem
- Department of Neurology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Brigitte Wildemann
- Molecular Neuroimmunology Group, Department of Neurology, University of Heidelberg, 69120 Heidelberg, Germany
| | - Armin M Nagel
- Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany.,Department of Diagnostic and Interventional Radiology, University Medical Centre Ulm, 89070 Ulm, Germany.,Institute of Radiology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - J Jordan
- Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany.,Institute of Radiology, University Hospital Erlangen, 91054 Erlangen, Germany
| | - Nadia Benkhedah
- Division of Medical Physics in Radiology, German Cancer Research Centre (DKFZ), 69120 Heidelberg, Germany
| | - Jens Kleesiek
- Multi-Dimensional Medical Imaging Lab, Department of Neuroradiology, University of Heidelberg, 69120 Heidelberg, Germany.,Multidimensional Image Processing Group, HCI/IWR, University of Heidelberg, 69120 Heidelberg, Germany
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22
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Yandamuri SS, Lane TE. Imaging Axonal Degeneration and Repair in Preclinical Animal Models of Multiple Sclerosis. Front Immunol 2016; 7:189. [PMID: 27242796 PMCID: PMC4871863 DOI: 10.3389/fimmu.2016.00189] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2016] [Accepted: 05/02/2016] [Indexed: 12/25/2022] Open
Abstract
Multiple sclerosis (MS) is a central nervous system (CNS) disease characterized by chronic neuroinflammation, demyelination, and axonal damage. Infiltration of activated lymphocytes and myeloid cells are thought to be primarily responsible for white matter damage and axonopathy. Over time, this neurologic damage manifests clinically as debilitating motor and cognitive symptoms. Existing MS therapies focus on symptom relief and delay of disease progression through reduction of neuroinflammation. However, long-term strategies to remyelinate, protect, or regenerate axons have remained elusive, posing a challenge to treating progressive forms of MS. Preclinical mouse models and techniques, such as immunohistochemistry, flow cytometry, and genomic and proteomic analysis have provided advances in our understanding of discrete time-points of pathology following disease induction. More recently, in vivo and in situ two-photon (2P) microscopy has made it possible to visualize continuous real-time cellular behavior and structural changes occurring within the CNS during neuropathology. Research utilizing 2P imaging to study axonopathy in neuroinflammatory demyelinating disease has focused on five areas: (1) axonal morphologic changes, (2) organelle transport and health, (3) relationship to inflammation, (4) neuronal excitotoxicity, and (5) regenerative therapies. 2P imaging may also be used to identify novel therapeutic targets via identification and clarification of dynamic cellular and molecular mechanisms of axonal regeneration and remyelination. Here, we review tools that have made 2P accessible for imaging neuropathologies and advances in our understanding of axonal degeneration and repair in preclinical models of demyelinating diseases.
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Affiliation(s)
| | - Thomas E. Lane
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
- Department of Pathology, School of Medicine, University of Utah, Salt Lake City, UT, USA
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23
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Clark KC, Josephson A, Benusa SD, Hartley RK, Baer M, Thummala S, Joslyn M, Sword BA, Elford H, Oh U, Dilsizoglu-Senol A, Lubetzki C, Davenne M, DeVries GH, Dupree JL. Compromised axon initial segment integrity in EAE is preceded by microglial reactivity and contact. Glia 2016; 64:1190-209. [PMID: 27100937 DOI: 10.1002/glia.22991] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Revised: 03/30/2016] [Accepted: 03/31/2016] [Indexed: 11/11/2022]
Abstract
Axonal pathology is a key contributor to long-term disability in multiple sclerosis (MS), an inflammatory demyelinating disease of the central nervous system (CNS), but the mechanisms that underlie axonal pathology in MS remain elusive. Evidence suggests that axonal pathology is a direct consequence of demyelination, as we and others have shown that the node of Ranvier disassembles following loss of myelin. In contrast to the node of Ranvier, we now show that the axon initial segment (AIS), the axonal domain responsible for action potential initiation, remains intact following cuprizone-induced cortical demyelination. Instead, we find that the AIS is disrupted in the neocortex of mice that develop experimental autoimmune encephalomyelitis (EAE) independent of local demyelination. EAE-induced mice demonstrate profound compromise of AIS integrity with a progressive disruption that corresponds to EAE clinical disease severity and duration, in addition to cortical microglial reactivity. Furthermore, treatment with the drug didox results in attenuation of AIS pathology concomitantly with microglial reversion to a less reactive state. Together, our findings suggest that inflammation, but not demyelination, disrupts AIS integrity and that therapeutic intervention may protect and reverse this pathology. GLIA 2016;64:1190-1209.
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Affiliation(s)
- Kareem C Clark
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,VCU, Neuroscience Curriculum, Richmond, Virginia
| | - Anna Josephson
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Savannah D Benusa
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,VCU, Neuroscience Curriculum, Richmond, Virginia
| | - Rebecca K Hartley
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Matthew Baer
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Suneel Thummala
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia
| | - Martha Joslyn
- Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | - Brooke A Sword
- Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | | | - Unsong Oh
- Department of Neurology, VCU, Richmond, Virginia
| | - Aysegul Dilsizoglu-Senol
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France
| | - Catherine Lubetzki
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France.,AP-HP, Hôpital De La Pitié Salpêtrière, Paris, F-75013, France
| | - Marc Davenne
- UPMC/Univ Paris 06 UMR S 1127, Institut Du Cerveau Et De La Moelle Épinière, ICM, Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, Paris, F-75013, France
| | - George H DeVries
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
| | - Jeffrey L Dupree
- Department of Anatomy and Neurobiology, Virginia Commonwealth University, Richmond, Virginia.,Department of Research,, Hunter Holmes McGuire VA Medical Center, Richmond, Virginia
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24
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Raftopoulos R, Hickman SJ, Toosy A, Sharrack B, Mallik S, Paling D, Altmann DR, Yiannakas MC, Malladi P, Sheridan R, Sarrigiannis PG, Hoggard N, Koltzenburg M, Gandini Wheeler-Kingshott CAM, Schmierer K, Giovannoni G, Miller DH, Kapoor R. Phenytoin for neuroprotection in patients with acute optic neuritis: a randomised, placebo-controlled, phase 2 trial. Lancet Neurol 2016; 15:259-69. [DOI: 10.1016/s1474-4422(16)00004-1] [Citation(s) in RCA: 131] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2015] [Revised: 12/10/2015] [Accepted: 01/04/2016] [Indexed: 01/04/2023]
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25
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Kumar P, Kumar D, Jha SK, Jha NK, Ambasta RK. Ion Channels in Neurological Disorders. ION CHANNELS AS THERAPEUTIC TARGETS, PART A 2016; 103:97-136. [DOI: 10.1016/bs.apcsb.2015.10.006] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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26
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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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27
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Alizadeh A, Dyck SM, Karimi-Abdolrezaee S. Myelin damage and repair in pathologic CNS: challenges and prospects. Front Mol Neurosci 2015; 8:35. [PMID: 26283909 PMCID: PMC4515562 DOI: 10.3389/fnmol.2015.00035] [Citation(s) in RCA: 132] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2015] [Accepted: 07/06/2015] [Indexed: 12/28/2022] Open
Abstract
Injury to the central nervous system (CNS) results in oligodendrocyte cell death and progressive demyelination. Demyelinated axons undergo considerable physiological changes and molecular reorganizations that collectively result in axonal dysfunction, degeneration and loss of sensory and motor functions. Endogenous adult oligodendrocyte precursor cells and neural stem/progenitor cells contribute to the replacement of oligodendrocytes, however, the extent and quality of endogenous remyelination is suboptimal. Emerging evidence indicates that optimal remyelination is restricted by multiple factors including (i) low levels of factors that promote oligodendrogenesis; (ii) cell death among newly generated oligodendrocytes, (iii) inhibitory factors in the post-injury milieu that impede remyelination, and (iv) deficient expression of key growth factors essential for proper re-construction of a highly organized myelin sheath. Considering these challenges, over the past several years, a number of cell-based strategies have been developed to optimize remyelination therapeutically. Outcomes of these basic and preclinical discoveries are promising and signify the importance of remyelination as a mechanism for improving functions in CNS injuries. In this review, we provide an overview on: (1) the precise organization of myelinated axons and the reciprocal axo-myelin interactions that warrant properly balanced physiological activities within the CNS; (2) underlying cause of demyelination and the structural and functional consequences of demyelination in axons following injury and disease; (3) the endogenous mechanisms of oligodendrocyte replacement; (4) the modulatory role of reactive astrocytes and inflammatory cells in remyelination; and (5) the current status of cell-based therapies for promoting remyelination. Careful elucidation of the cellular and molecular mechanisms of demyelination in the pathologic CNS is a key to better understanding the impact of remyelination for CNS repair.
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Affiliation(s)
- Arsalan Alizadeh
- Regenerative Medicine Program, Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg MB, Canada
| | - Scott M Dyck
- Regenerative Medicine Program, Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg MB, Canada
| | - Soheila Karimi-Abdolrezaee
- Regenerative Medicine Program, Department of Physiology and Pathophysiology, Spinal Cord Research Centre, Faculty of Health Sciences, College of Medicine, University of Manitoba, Winnipeg MB, Canada
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28
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Wang C, Paling D, Chen L, Hatton SN, Lagopoulos J, Aw ST, Kiernan MC, Barnett MH. Axonal conduction in multiple sclerosis: A combined magnetic resonance imaging and electrophysiological study of the medial longitudinal fasciculus. Mult Scler 2014; 21:905-15. [DOI: 10.1177/1352458514556301] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Accepted: 09/17/2014] [Indexed: 12/30/2022]
Abstract
Objective: The objective of this paper is to inform the pathophysiology of medial longitudinal fasciculus (MLF) axonal dysfunction in patients with internuclear ophthalmoplegia (INO) due to multiple sclerosis (MS), and develop a composite structural-functional biomarker of axonal and myelin integrity in this tract. Methods: Eighteen patients with definite MS and clinically suspected INO underwent electrical vestibular stimulation and search-coil eye movement recording. Components of the electrically evoked vestibulo-ocular reflex (eVOR) were analyzed to probe the latency and fidelity of MLF axonal conduction. The MLF and T2-visible brainstem lesions were defined by high-resolution MRI. White matter integrity was determined by diffusion-weighted imaging metrics. Results: eVOR onset latency was positively correlated with MLF lesion length (left: r = 0.66, p = 0.004; right: r = 0.75, p = 0.001). The mean conduction velocity (±SD) within MLF lesions was estimated at 2.72 (±0.87) m/s. eVOR onset latency correlated with normalized axial diffusivity ( r = 0.66, p < 0.001) and fractional anisotropy ( r = 0.44, p = 0.02) after exclusion of cases with ipsilateral vestibular root entry zone lesions. Conclusions: Axonal conduction velocity through lesions involving the MLF was reduced below levels predicted for natively myelinated and remyelinated axons. Composite in vivo biomarkers enable delineation of axonal from myelin processes and may provide a crucial role in assessing efficacy of novel reparative therapies in MS.
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Affiliation(s)
- Chenyu Wang
- Sydney Neuroimaging Analysis Centre, Sydney, Australia/Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - David Paling
- Royal Hallamshire Hospital, Sheffield, UK and Department of Neuroscience, University of Sheffield, Sheffield, UK
| | - Luke Chen
- Central Clinical School, University of Sydney, Sydney, Australia/Royal Prince Alfred Hospital, Sydney, Australia
| | - Sean N Hatton
- Sydney Neuroimaging Analysis Centre, Sydney, Australia/Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Jim Lagopoulos
- Sydney Neuroimaging Analysis Centre, Sydney, Australia/Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Swee T Aw
- Central Clinical School, University of Sydney, Sydney, Australia/Royal Prince Alfred Hospital, Sydney, Australia
| | - Matthew C Kiernan
- Brain and Mind Research Institute, University of Sydney, Sydney, Australia
| | - Michael H Barnett
- Sydney Neuroimaging Analysis Centre, Sydney, Australia/Brain and Mind Research Institute, University of Sydney, Sydney, Australia/Royal Prince Alfred Hospital, Sydney, Australia
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Lee JY, Taghian K, Petratos S. Axonal degeneration in multiple sclerosis: can we predict and prevent permanent disability? Acta Neuropathol Commun 2014; 2:97. [PMID: 25159125 PMCID: PMC4243718 DOI: 10.1186/s40478-014-0097-7] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2014] [Accepted: 08/06/2014] [Indexed: 12/24/2022] Open
Abstract
Axonal degeneration is a major determinant of permanent neurological impairment during multiple sclerosis (MS). Due to the variable course of clinical disease and the heterogeneity of MS lesions, the mechanisms governing axonal degeneration may differ between disease stages. While the etiology of MS remains elusive, there now exist potential prognostic biomarkers that can predict the conversion to clinically definite MS. Specialized imaging techniques identifying axonal injury and drop-out are becoming established in clinical practice as a predictive measure of MS progression, such as optical coherence tomography (OCT) or diffusion tensor imaging (DTI). However, these imaging techniques are still being debated as predictive biomarkers since controversy surrounds their lesion-specific association with expanded disability status scale (EDSS). A more promising diagnostic measure of axonal degeneration has been argued for the detection of reduced N-acetyl aspartate (NAA) and Creatine ratios via magnetic resonance spectroscopic (MRS) imaging, but again fail with its specificity for predicting actual axonal degeneration. Greater accuracy of predictive biomarkers is therefore warranted and may include CSF neurofilament light chain (NF-L) and neurofilament heavy chain (NF-H) levels, for progressive MS. Furthermore, defining the molecular mechanisms that occur during the neurodegenerative changes in the various subgroups of MS may in fact prove vital for the future development of efficacious neuroprotective therapies. The clinical translation of a combined Na+ and Ca2+ channel blocker may lead to the establishment of a bona fide neuroprotective agent for the treatment of progressive MS. However, more specific therapeutic targets to limit axonal damage in MS need investigation and may include such integral axonal proteins such as the collapsin response mediator protein-2 (CRMP-2), a molecule which upon post-translational modification may propagate axonal degeneration in MS. In this review, we discuss the current clinical determinants of axonal damage in MS and consider the cellular and molecular mechanisms that may initiate these neurodegenerative changes. In particular we highlight the therapeutic candidates that may formulate novel therapeutic strategies to limit axonal degeneration and EDSS during progressive MS.
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Bouafia A, Golmard JL, Thuries V, Sazdovitch V, Hauw JJ, Fontaine B, Seilhean D. Axonal expression of sodium channels and neuropathology of the plaques in multiple sclerosis. Neuropathol Appl Neurobiol 2014; 40:579-90. [DOI: 10.1111/nan.12059] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2012] [Revised: 05/10/2013] [Accepted: 04/30/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Adel Bouafia
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM); INSERM UMR_S975; CNRS UMR7225; UPMC-Sorbonne Universités; Groupe Hospitalier Pitié-Salpêtrière; Paris France
| | - Jean-Louis Golmard
- Modélisation en recherche clinique ER4; UF de biostatistique; Université Pierre et Marie Curie et Groupe Hospitalier Pitié-Salpêtrière; Paris France
| | - Valerie Thuries
- Laboratoire de Neuropathologie Raymond Escourolle; Groupe Hospitalier Pitié-Salpêtrière; Paris France
| | - Veronique Sazdovitch
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM); INSERM UMR_S975; CNRS UMR7225; UPMC-Sorbonne Universités; Groupe Hospitalier Pitié-Salpêtrière; Paris France
- Laboratoire de Neuropathologie Raymond Escourolle; Groupe Hospitalier Pitié-Salpêtrière; Paris France
| | - Jean Jacques Hauw
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM); INSERM UMR_S975; CNRS UMR7225; UPMC-Sorbonne Universités; Groupe Hospitalier Pitié-Salpêtrière; Paris France
- Laboratoire de Neuropathologie Raymond Escourolle; Groupe Hospitalier Pitié-Salpêtrière; Paris France
- Académie Nationale de Médecine; Paris France
| | - Betrand Fontaine
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM); INSERM UMR_S975; CNRS UMR7225; UPMC-Sorbonne Universités; Groupe Hospitalier Pitié-Salpêtrière; Paris France
- Fédération des Maladies du Système Nerveux; Groupe Hospitalier Pitié-Salpêtrière; Paris France
| | - Danielle Seilhean
- Centre de Recherche de l'Institut du Cerveau et de la Moelle Épinière (CRICM); INSERM UMR_S975; CNRS UMR7225; UPMC-Sorbonne Universités; Groupe Hospitalier Pitié-Salpêtrière; Paris France
- Laboratoire de Neuropathologie Raymond Escourolle; Groupe Hospitalier Pitié-Salpêtrière; Paris France
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31
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Abstract
PURPOSE OF REVIEW The predominant clinical disease course of multiple sclerosis starts with reversible episodes of neurological disability, which transforms into progressive neurological decline. This review provides insight into the pathological differences during relapsing and progressive phases of multiple sclerosis. RECENT FINDINGS The clinical course of multiple sclerosis is variable, and the disease can be classified into relapsing and progressive phases. Pathological studies have been successful in distinguishing between these two forms of the disease and correlate with the clinical findings in terms of cellular responses, the inflammatory environment, and the location of lesions. SUMMARY Available therapies for multiple sclerosis patients, while effective during the relapsing phase, have little benefit for progressive multiple sclerosis patients. Development of therapies to benefit progressive multiple sclerosis patients will require a better understanding of the pathogenesis of progressive multiple sclerosis. This review discusses and compares the pathological findings in relapsing and progressive multiple sclerosis patients.
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Affiliation(s)
- Ranjan Dutta
- Department of Neurosciences, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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32
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Two-photon imaging of remyelination of spinal cord axons by engrafted neural precursor cells in a viral model of multiple sclerosis. Proc Natl Acad Sci U S A 2014; 111:E2349-55. [PMID: 24843159 DOI: 10.1073/pnas.1406658111] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Neural precursor cells (NPCs) offer a promising approach for treating demyelinating diseases. However, the cellular dynamics that underlie transplanted NPC-mediated remyelination have not been described. Using two-photon imaging of a newly developed ventral spinal cord preparation and a viral model of demyelination, we describe the motility and intercellular interactions of transplanted mouse NPCs expressing green fluorescent protein (GFP) with damaged axons expressing yellow fluorescent protein (YFP). Our findings reveal focal axonal degeneration that occurs in the ventral side of the spinal cord within 1 wk following intracranial instillation with the neurotropic JHM strain of mouse hepatitis virus (JHMV). Axonal damage precedes extensive demyelination and is characterized by swelling along the length of the axon, loss of YFP signal, and transected appearance. NPCs engrafted into spinal cords of JHMV-infected mice exhibited diminished migration velocities and increased proliferation compared with transplanted cells in noninfected mice. NPCs preferentially accumulated within areas of axonal damage, initiated direct contact with axons, and subsequently expressed the myelin proteolipid protein gene, initiating remyelination. These findings indicate that NPCs transplanted into an inflammatory demyelinating microenvironment participate directly in therapeutic outcome through the wrapping of myelin around damaged neurons.
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33
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Kuračka Ľ, Kalnovičová T, Kucharská J, Turčáni P. Multiple sclerosis: evaluation of purine nucleotide metabolism in central nervous system in association with serum levels of selected fat-soluble antioxidants. Mult Scler Int 2014; 2014:759808. [PMID: 24891952 PMCID: PMC4033398 DOI: 10.1155/2014/759808] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2014] [Accepted: 04/14/2014] [Indexed: 11/17/2022] Open
Abstract
In the pathogenesis of demyelinating diseases including multiple sclerosis (MS) an important role is played by oxidative stress. Increased energy requirements during remyelination of axons and mitochondria failure is one of the causes of axonal degeneration and disability in MS. In this context, we analyzed to what extent the increase in purine catabolism is associated with selected blood lipophilic antioxidants and if there is any association with alterations in serum levels of coenzyme Q10. Blood serum and cerebrospinal fluid (CSF) samples from 42 patients with diagnosed MS and 34 noninflammatory neurologic patients (control group) were analyzed. Compared to control group, MS patients had significantly elevated values of all purine nucleotide metabolites, except adenosine. Serum lipophilic antioxidants γ -tocopherol, β -carotene, and coenzyme Q10 for the vast majority of MS patients were deficient or moved within the border of lower physiological values. Serum levels of TBARS, marker of lipid peroxidation, were increased by 81% in the MS patients. The results indicate that the deficit of lipophilic antioxidants in blood of MS patients may have a negative impact on bioenergetics of reparative remyelinating processes and promote neurodegeneration.
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Affiliation(s)
- Ľubomír Kuračka
- Institute of Medical Chemistry, Biochemistry and Clinical Biochemistry, Faculty of Medicine, Comenius University, 811 08 Bratislava, Slovakia
| | - Terézia Kalnovičová
- 1st Department of Neurology, Faculty of Medicine, Comenius University, 813 69 Bratislava, Slovakia
| | - Jarmila Kucharská
- Pharmacobiochemical Laboratory of 3rd Medical Clinic, Faculty of Medicine, Comenius University, 811 08 Bratislava, Slovakia
| | - Peter Turčáni
- 1st Department of Neurology, Faculty of Medicine, Comenius University, 813 69 Bratislava, Slovakia
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34
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Levin MC, Douglas JN, Meyers L, Lee S, Shin Y, Gardner LA. Neurodegeneration in multiple sclerosis involves multiple pathogenic mechanisms. Degener Neurol Neuromuscul Dis 2014; 4:49-63. [PMID: 32669900 PMCID: PMC7337253 DOI: 10.2147/dnnd.s54391] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 03/06/2014] [Indexed: 12/18/2022] Open
Abstract
Multiple sclerosis (MS) is a complex autoimmune disease that impairs the central nervous system (CNS). The neurological disability and clinical course of the disease is highly variable and unpredictable from one patient to another. The cause of MS is still unknown, but it is thought to occur in genetically susceptible individuals who develop disease due to a nongenetic trigger, such as altered metabolism, a virus, or other environmental factors. MS patients develop progressive, irreversible, neurological disability associated with neuronal and axonal damage, collectively known as neurodegeneration. Neurodegeneration was traditionally considered as a secondary phenomenon to inflammation and demyelination. However, recent data indicate that neurodegeneration develops along with inflammation and demyelination. Thus, MS is increasingly recognized as a neurodegenerative disease triggered by an inflammatory attack of the CNS. While both inflammation and demyelination are well described and understood cellular processes, neurodegeneration might be defined by a diverse pool of any of the following: neuronal cell death, apoptosis, necrosis, and virtual hypoxia. In this review, we present multiple theories and supporting evidence that identify common biological processes that contribute to neurodegeneration in MS.
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Affiliation(s)
- Michael C Levin
- Veterans Administration Medical Center.,Department of Neuroscience, University of Tennessee Health Science Center, Memphis, TN, USA
| | - Joshua N Douglas
- Veterans Administration Medical Center.,Department of Neuroscience, University of Tennessee Health Science Center, Memphis, TN, USA
| | | | - Sangmin Lee
- Veterans Administration Medical Center.,Department of Neurology
| | - Yoojin Shin
- Veterans Administration Medical Center.,Department of Neurology
| | - Lidia A Gardner
- Veterans Administration Medical Center.,Department of Neurology
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35
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36
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Fairless R, Williams SK, Diem R. Dysfunction of neuronal calcium signalling in neuroinflammation and neurodegeneration. Cell Tissue Res 2013; 357:455-62. [PMID: 24326615 DOI: 10.1007/s00441-013-1758-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 10/31/2013] [Indexed: 02/07/2023]
Abstract
Neurodegeneration has been increasingly recognised as the leading structural correlate of disability progression in autoimmune diseases such as multiple sclerosis. Since calcium signalling is known to regulate the development of degenerative processes in many cell types, it is believed to play significant roles in mediating neurodegeneration. Because of its function as a major juncture linking various insults and injuries associated with inflammatory attack on neuronal cell bodies and axons, it provides potential for the development of neuroprotective strategies. This is of great significance because of the lack of neuroprotective agents presently available to supplement the current array of immunomodulatory treatments. In this review, we summarise the role that various calcium channels and pumps have been shown to play in the development of neurodegeneration under inflammatory autoimmune conditions. The identification of suitable targets might also provide insights into applications in non-inflammatory neurodegenerative diseases.
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Affiliation(s)
- Richard Fairless
- Department of Neuro-oncology, University Clinic Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Germany
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37
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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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38
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Paling D, Solanky BS, Riemer F, Tozer DJ, Wheeler-Kingshott CAM, Kapoor R, Golay X, Miller DH. Sodium accumulation is associated with disability and a progressive course in multiple sclerosis. Brain 2013; 136:2305-17. [DOI: 10.1093/brain/awt149] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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39
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Nav1.8 expression is not restricted to nociceptors in mouse peripheral nervous system. Pain 2012; 153:2017-2030. [PMID: 22703890 DOI: 10.1016/j.pain.2012.04.022] [Citation(s) in RCA: 202] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2011] [Revised: 03/23/2012] [Accepted: 04/25/2012] [Indexed: 12/22/2022]
Abstract
A vast diversity of salient cues is sensed by numerous classes of primary sensory neurons, defined by specific neuropeptides, ion channels, or cytoskeletal proteins. Recent evidence has demonstrated a correlation between the expression of some of these molecular markers and transmission of signals related to distinct sensory modalities (eg, heat, cold, pressure). Voltage-gated sodium channel Na(v)1.8 has been reported to be preferentially expressed in small-diameter unmyelinated sensory afferents specialized for the detection of noxious stimuli (nociceptors), and Na(v)1.8-Cre mice have been widely used to investigate gene function in nociceptors. However, the identity of neurons in which Cre-mediated recombination occurs in these animals has not been resolved, and whether expression of Na(v)1.8 in these neurons is dynamic during development is not known, rendering interpretation of conditional knockout mouse phenotypes problematic. Here, we used genetics, immunohistochemistry, electrophysiology, and calcium imaging to precisely characterize the expression of Na(v)1.8 in the peripheral nervous system. We demonstrate that 75% of dorsal root ganglion (DRG) neurons express Na(v)1.8-Cre, including >90% of neurons expressing markers of nociceptors and, unexpectedly, a large population (∼40%) of neurons with myelinated A fibers. Furthermore, analysis of DRG neurons' central and peripheral projections revealed that Na(v)1.8-Cre is not restricted to nociceptors but is also expressed by at least 2 types of low-threshold mechanoreceptors essential for touch sensation, including those with C and Aβ fibers. Our results indicate that Na(v)1.8 underlies electrical activity of sensory neurons subserving multiple functional modalities, and call for cautious interpretation of the phenotypes of Na(v)1.8-Cre-driven conditional knockout mice.
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40
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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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41
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Mai W, Hu X, Lu Z, Peng F, Wang Y. Cerebrospinal Fluid Levels of Soluble Amyloid Precursor Protein and β-Amyloid 42 in Patients with Multiple Sclerosis, Neuromyelitis Optica and Clinically Isolated Syndrome. J Int Med Res 2011; 39:2402-13. [PMID: 22289560 DOI: 10.1177/147323001103900641] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Amyloid precursor protein (APP) accumulation in axonal ovoids is a sensitive marker for acute axonal injury in multiple sclerosis (MS) lesions. This study measured levels of α-cleaved soluble APP (αsAPP) and β-amyloid 42 (Aβ42) in the cerebrospinal fluid (CSF) of 42 MS, 10 neuromyelitis optica and 25 clinically isolated syndrome patients and 21 healthy controls, and analysed the correlation between αsAPP and Aβ42 levels and relevant clinical parameters. The CSF concentrations of αsAPP and Aβ42 in patients and controls were not significantly different. There was a significant inverse correlation in patients between CSF asAPP concentration and the Expanded Disability Status Scale (EDSS), but no significant correlation between CSF Aβ42 concentration and EDSS. The concentration of αsAPP in the CSF of statin-treated patients was significantly higher than in those not treated with statins, suggesting that statins may have a neuroprotective effect. In conclusion, αsAPP was present at similar levels in the CSF of patients with neuromyelitis optica, MS and clinically isolated syndrome and healthy controls, and an inverse correlation existed between CSF αsAPP concentration and neurological disability.
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Affiliation(s)
- W Mai
- Department of Neurology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Zhuhai, China
| | - X Hu
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Z Lu
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - F Peng
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
| | - Y Wang
- Department of Neurology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China
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42
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Campbell GR, Mahad DJ. Mitochondria as crucial players in demyelinated axons: lessons from neuropathology and experimental demyelination. Autoimmune Dis 2011; 2011:262847. [PMID: 21331147 PMCID: PMC3038418 DOI: 10.4061/2011/262847] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 11/29/2010] [Indexed: 01/18/2023] Open
Abstract
Mitochondria are the most efficient producers of energy in the form of ATP. Energy demands of axons, placed at relatively great distances from the neuronal cell body, are met by mitochondria, which when functionally compromised, produce reactive oxygen species (ROS) in excess. Axons are made metabolically efficient by myelination, which enables saltatory conduction. The importance of mitochondria for maintaining the structural integrity of myelinated axons is illustrated by neuroaxonal degeneration in primary mitochondrial disorders. When demyelinated, the compartmentalisation of ion channels along axons is disrupted. The redistribution of electrogenic machinery is thought to increase the energy demand of demyelinated axons. We review related studies that focus on mitochondria within unmyelinated, demyelinated and dysmyelinated axons in the central nervous system. Based on neuropathological observations we propose the increase in mitochondrial presence within demyelinated axons as an adaptive process to the increased energy need. An increased presence of mitochondria would also increase the capacity to produce deleterious agents such as ROS when functionally compromised. Given the lack of direct evidence of a beneficial or harmful effect of mitochondrial changes, the precise role of increased mitochondrial presence within axons due to demyelination needs to be further explored in experimental demyelination in-vivo and in-vitro.
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Affiliation(s)
- Graham R Campbell
- Mitochondrial Research Group, Institute for Ageing and Health, Newcastle University, Framlington Place, Newcastle upon Tyne, NE2 4HH, UK
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43
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Schirmer L, Antel JP, Brück W, Stadelmann C. Axonal loss and neurofilament phosphorylation changes accompany lesion development and clinical progression in multiple sclerosis. Brain Pathol 2011; 21:428-40. [PMID: 21114565 DOI: 10.1111/j.1750-3639.2010.00466.x] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Neuroaxonal damage and loss are increasingly recognized as disability determining features in multiple sclerosis (MS) pathology. However, little is known about the long-term sequelae of inflammatory demyelination on neurons and axons. Spinal cord tissue of 31 MS patients was compared to three amyotrophic lateral sclerosis (ALS) and 10 control subjects. MS lesions were staged according to the density of KiM-1P positive macrophages and microglia and the presence of myelin basic protein (MBP) positive phagocytes. T cells were quantified in the parenchyma and meninges. Neuroaxonal changes were studied by immunoreactivity (IR) for amyloid precursor protein (APP) and variably phosphorylated neurofilaments (SMI312, SMI31, SMI32). Little T cell infiltration was still evident in chronic inactive lesions. The loss of SMI32 IR in ventral horn neurons correlated with MS lesion development and disease progression. Similarly, axonal loss in white matter (WM) lesions correlated with disease duration. A selective reduction of axonal phosphorylated neurofilaments (SMI31) was observed in WM lesions. In ALS, the loss of neuronal SMI32 IR was even more pronounced, whereas the relative axonal reduction resembled that found in MS. Progressive neuroaxonal neurofilament alterations in the context of chronic inflammatory demyelination may reflect changes in neuroaxonal metabolism and result in chronic neuroaxonal dysfunction as a putative substrate of clinical progression.
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Affiliation(s)
- Lucas Schirmer
- Department of Neuropathology, University Medical Centre Göttingen, Germany
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44
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Activated microglia mediate axoglial disruption that contributes to axonal injury in multiple sclerosis. J Neuropathol Exp Neurol 2010; 69:1017-1033. [PMID: 20838243 DOI: 10.1097/nen.0b013e3181f3a5b1] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
The complex manifestations of chronic multiple sclerosis (MS)are due in part to widespread axonal abnormalities that affect lesional and nonlesional areas in the central nervous system. We describe an association between microglial activation and axon/oligodendrocyte pathology at nodal and paranodal domains in normal-appearing white matter (NAWM) of MS cases and in experimental autoimmune encephalomyelitis (EAE). The extent of paranodal axoglial (neurofascin-155(+)/Caspr1(+)) disruption correlated with local microglial inflammation and axonal injury (expression of nonphosphorylated neurofilaments) in MS NAWM. These changes were independent of demyelinating lesions and did not correlate with the density of infiltrating lymphocytes. Similar axoglial alterations were seen in the subcortical white matter of Parkinson disease cases and in preclinical EAE, at a time point when there is microglial activation before the infiltration of immune cells. Disruption of the axoglial unit in adjuvant-immunized animals was reversible and coincided with the resolution of microglial inflammation; paranodal damage and microglial inflammation persisted in chronic EAE. Axoglial integrity could be preserved by the administration of minocycline, which inhibited microglial activation, in actively immunized animals. These data indicate that, in MS NAWM, permanent disruption to axoglial domains in an environment of microglial inflammation is an early indicator of axonal injury that likely affects nerve conduction and may contribute to physiologic dysfunction.
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45
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Dutta R, Trapp BD. Mechanisms of neuronal dysfunction and degeneration in multiple sclerosis. Prog Neurobiol 2010; 93:1-12. [PMID: 20946934 DOI: 10.1016/j.pneurobio.2010.09.005] [Citation(s) in RCA: 313] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 09/14/2010] [Accepted: 09/30/2010] [Indexed: 01/18/2023]
Abstract
Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Due to its high prevalence, MS is the leading cause of non-traumatic neurological disability in young adults in the United States and Europe. The clinical disease course is variable and starts with reversible episodes of neurological disability in the third or fourth decade of life. This transforms into a disease of continuous and irreversible neurological decline by the sixth or seventh decade. Available therapies for MS patients have little benefit for patients who enter this irreversible phase of the disease. It is well established that irreversible loss of axons and neurons are the major cause of the irreversible and progressive neurological decline that most MS patients endure. This review discusses the etiology, mechanisms and progress made in determining the cause of axonal and neuronal loss in MS.
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Affiliation(s)
- Ranjan Dutta
- Department of Neurosciences/NC30, Lerner Research Institute, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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46
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Crawford DK, Mangiardi M, Song B, Patel R, Du S, Sofroniew MV, Voskuhl RR, Tiwari-Woodruff SK. Oestrogen receptor beta ligand: a novel treatment to enhance endogenous functional remyelination. ACTA ACUST UNITED AC 2010; 133:2999-3016. [PMID: 20858739 PMCID: PMC2947430 DOI: 10.1093/brain/awq237] [Citation(s) in RCA: 104] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Demyelinating diseases, such as multiple sclerosis, are characterized by inflammatory demyelination and neurodegeneration of the central nervous system. Therapeutic strategies that induce effective neuroprotection and enhance intrinsic repair mechanisms are central goals for future therapy of multiple sclerosis. Oestrogens and oestrogen receptor ligands are promising treatments to prevent multiple sclerosis-induced neurodegeneration. In the present study we investigated the capacity of oestrogen receptor β ligand treatment to affect callosal axon demyelination and stimulate endogenous myelination in chronic experimental autoimmune encephalomyelitis using electrophysiology, electron microscopy, immunohistochemistry and tract-tracing methods. Oestrogen receptor β ligand treatment of experimental autoimmune encephalomyelitis mice prevented both histopathological and functional abnormalities of callosal axons despite the presence of inflammation. Specifically, there were fewer demyelinated, damaged axons and more myelinated axons with intact nodes of Ranvier in oestrogen receptor β ligand-treated mice. In addition, oestrogen receptor β ligand treatment caused an increase in mature oligodendrocyte numbers, a significant increase in myelin sheath thickness and axon transport. Functional analysis of callosal axon conduction showed a significant improvement in compound action potential amplitudes, latency and in axon refractoriness. These findings show a direct neuroprotective effect of oestrogen receptor β ligand treatment on oligodendrocyte differentiation, myelination and axon conduction during experimental autoimmune encephalomyelitis.
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Affiliation(s)
- Daniel K Crawford
- Multiple Sclerosis Program at UCLA, Department of Neurology, School of Medicine, University of California-Los Angeles, 635 Charles E Young Drive, Los Angeles, CA 90095-1769, USA
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47
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Sättler MB, Bähr M. Future neuroprotective strategies. Exp Neurol 2010; 225:40-7. [DOI: 10.1016/j.expneurol.2009.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Revised: 08/18/2009] [Accepted: 08/19/2009] [Indexed: 12/27/2022]
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Kapoor R, Furby J, Hayton T, Smith KJ, Altmann DR, Brenner R, Chataway J, Hughes RAC, Miller DH. Lamotrigine for neuroprotection in secondary progressive multiple sclerosis: a randomised, double-blind, placebo-controlled, parallel-group trial. Lancet Neurol 2010; 9:681-8. [PMID: 20621711 DOI: 10.1016/s1474-4422(10)70131-9] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Partial blockade of voltage-gated sodium channels is neuroprotective in experimental models of inflammatory demyelinating disease. In this phase 2 trial, we aimed to assess whether the sodium-channel blocker lamotrigine is also neuroprotective in patients with secondary progressive multiple sclerosis. METHODS Patients with secondary progressive multiple sclerosis who attended the National Hospital for Neurology and Neurosurgery or the Royal Free Hospital, London, UK, were eligible for inclusion in this double-blind, parallel-group trial. Patients were randomly assigned via a website by minimisation to receive lamotrigine (target dose 400 mg/day) or placebo for 2 years. Treating physicians, evaluating physicians, and patients were masked to treatment allocation. The primary outcome was the rate of change of partial (central) cerebral volume over 24 months. All patients who were randomly assigned were included in the primary analysis. This trial is registered with ClinicalTrials.gov, NCT00257855. FINDINGS 120 patients were randomly assigned to treatment (87 women and 33 men): 61 to lamotrigine and 59 to placebo. 108 patients were analysed for the primary endpoint: 52 in the lamotrigine group and 56 in the placebo group. The mean change in partial (central) cerebral volume per year was -3.18 mL (SD -1.25) in the lamotrigine group and -2.48 mL (-0.97) in the placebo group (difference -0.71 mL, 95% CI -2.56 to 1.15; p=0.40). However, in an exploratory modelling analysis, lamotrigine treatment seemed to be associated with greater partial (central) cerebral volume loss than was placebo in the first year (p=0.04), and volume increased partially after treatment stopped (p=0.04). Lamotrigine treatment reduced the deterioration of the timed 25-foot walk (p=0.02) but did not affect other secondary clinical outcome measures. Rash and dose-related deterioration of gait and balance were experienced more by patients in the lamotrigine group than the placebo group. INTERPRETATION The effect of lamotrigine on cerebral volume of patients with secondary progressive multiple sclerosis did not differ from that of placebo over 24 months, but lamotrigine seemed to cause early volume loss that reversed partially on discontinuation of treatment. Future trials of neuroprotection in multiple sclerosis should include investigation of complex early volume changes in different compartments of the CNS, effects unrelated to neurodegeneration, and targeting of earlier and more inflammatory disease. FUNDING Multiple Sclerosis Society of Great Britain and Northern Ireland.
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Affiliation(s)
- Raju Kapoor
- Department of Neuroinflammation, National Hospital for Neurology and Neurosurgery and the Institute of Neurology, Queen Square, London, UK.
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Lazzarino G, Amorini AM, Eikelenboom MJ, Killestein J, Belli A, Di Pietro V, Tavazzi B, Barkhof F, Polman CH, Uitdehaag BMJ, Petzold A. Cerebrospinal fluid ATP metabolites in multiple sclerosis. Mult Scler 2010; 16:549-54. [PMID: 20194579 DOI: 10.1177/1352458510364196] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increased axonal energy demand and mitochondrial failure have been suggested as possible causes for axonal degeneration and disability in multiple sclerosis. Our objective was to test whether ATP depletion precedes clinical, imaging and biomarker evidence for axonal degeneration in multiple sclerosis. The method consisted of a longitudinal study which included 21 patients with multiple sclerosis. High performance liquid chromatography was used to quantify biomarkers of the ATP metabolism (oxypurines and purines) from the cerebrospinal fluid at baseline. The Expanded Disability Status Scale, MRI brain imaging measures for brain atrophy (ventricular and parenchymal fractions), and cerebrospinal fluid biomarkers for axonal damage (phosphorylated and hyperphosphorylated neurofilaments) were quantified at baseline and 3-year follow-up. Central ATP depletion (sum of ATP metabolites >19.7 micromol/litre) was followed by more severe progression of disability if compared to normal ATP metabolites (median 1.5 versus 0, p< 0.05). Baseline ATP metabolite levels correlated with change of Expanded Disability Status Scale in the pooled cohort (r= 0.66, p= 0.001) and subgroups (relapsing-remitting patients: r= 0.79, p< 0.05 and secondary progressive/primary progressive patients: r= 0.69, p< 0.01). There was no relationship between central ATP metabolites and either biomarker or MRI evidence for axonal degeneration. The data suggests that an increased energy demand in multiple sclerosis may cause a quantifiable degree of central ATP depletion. We speculate that the observed clinical disability may be related to depolarisation associated conduction block.
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Affiliation(s)
- G Lazzarino
- Department of Chemical Sciences, Laboratory of Biochemistry, University of Catania, Italy
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Black JA, Newcombe J, Waxman SG. Astrocytes within multiple sclerosis lesions upregulate sodium channel Nav1.5. Brain 2010; 133:835-46. [PMID: 20147455 DOI: 10.1093/brain/awq003] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Astrocytes are prominent participants in the response of the central nervous system to injury, including neuroinflammatory insults. Rodent astrocytes in vitro have been shown to express voltage-gated sodium channels in a dynamic manner, with a switch in expression of tetrodotoxin-sensitive to tetrodotoxin-resistant channels in reactive astrocytes. However, the expression of sodium channels in human astrocytes has not been studied, and it is not known whether there are changes in the expression of sodium channels in reactive astrocytes of the human central nervous system. Here, we demonstrate a focal and robust upregulation of sodium channel Nav1.5 in reactive astrocytes at the borders of, and within, active and chronic multiple sclerosis lesions. Nav1.5 was only detectable at very low levels in astrocytes within multiple sclerosis macroscopically normal-appearing white matter or in normal control brain. Nav1.1, Nav1.2, Nav1.3 and Nav1.6 showed little or no expression in astrocytes within normal control tissue and limited upregulation in active multiple sclerosis lesions. Nav1.5 was also expressed at high levels in astrocytes in tissue surrounding new and old cerebrovascular accidents and brain tumours. These results demonstrate the expression of Nav1.5 in human astrocytes and show that Nav1.5 expression is dynamic in these cells. Our observations suggest that the upregulated expression of Nav1.5 in astrocytes may provide a compensatory mechanism, which supports sodium/potassium pump-dependent ionic homoeostasis in areas of central nervous system injury.
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Affiliation(s)
- Joel A Black
- Neuroscience Research Centre (Bldg 34), VA Connecticut Healthcare System (127A), 950 Campbell Avenue, West Haven, CT 06516, USA
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