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ELBini I, Neili NE. Potassium channels at the crossroads of neuroinflammation and myelination in experimental models of multiple sclerosis. Biochem Biophys Res Commun 2023; 653:140-146. [PMID: 36870238 DOI: 10.1016/j.bbrc.2023.02.066] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/16/2023] [Accepted: 02/23/2023] [Indexed: 03/06/2023]
Abstract
Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system (CNS), characterized by the presence of localized demyelinating lesions accompanied by an inflammatory reaction, evidently leading to neurodegeneration. A number of ion channels have been implicated in the progression of MS, most notably in cell types involved in the immune response. In the present study, we investigated the implication of two ion channel isoforms, Kv1.1 and Kv1.3, in experimental models of neuroinflammation and demyelination. Immunohistochemical staining of brain sections from the mouse cuprizone model displayed high levels Kv1.3 expression. In an astroglial cellular model of inflammation, stimulation with LPS resulted also in a higher expression of Kv1.1 and Kv1.3, while the introduction of 4-Aminopyridine (4-AP) exacerbated the release of pro-inflammatory chemokine CXCL10. In the oligodendroglial cellular model of demyelination, the alteration in expression levels of Kv1.1 and Kv1.3 may be correlated with that of MBP levels. Indirect co-culture was attempted to further understand the communication between astrocytes and oligodendrocytes, The addition of reactive astrocytes' secretome significantly inhibited the production of MBP, this inhibition was accompanied by an alteration in the expression of Kv1.1 and Kv1.3. The addition of 4-AP in this case did not alleviate the decrease in MBP production. In conclusion, the use of 4-AP generated controversial results, suggesting 4-AP may be used in the early stages of the disease or in the remission phases to stimulate myelination, yet in induced toxic inflammatory environment, 4-AP exacerbated this effect.
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Affiliation(s)
- Ines ELBini
- Laboratoire des Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, 1002, Tunisia.
| | - Nour-Elhouda Neili
- Laboratoire des Biomolécules, Venins et Applications Théranostiques (LR20IPT01), Institut Pasteur de Tunis, Université de Tunis El Manar, Tunis, 1002, Tunisia.
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2
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Kettwig M, Klemp H, Nessler S, Streit F, Krätzner R, Rosewich H, Gärtner J. Targeted metabolomics revealed changes in phospholipids during the development of neuroinflammation in Abcd1 tm1Kds mice and X-linked adrenoleukodystrophy patients. J Inherit Metab Dis 2021; 44:1174-1185. [PMID: 33855724 DOI: 10.1002/jimd.12389] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 11/06/2022]
Abstract
X-linked adrenoleukodystrophy (X-ALD) is the most common leukodystrophy. Despite intensive research in recent years, it remains unclear, what drives the different clinical disease courses. Due to this missing pathophysiological link, therapy for the childhood cerebral disease course of X-ALD (CCALD) remains symptomatic; the allogenic hematopoietic stem cell transplantation or hematopoietic stem-cell gene therapy is an option for early disease stages. The inclusion of dried blood spot (DBS) C26:0-lysophosphatidylcholine to newborn screening in an increasing number of countries is leading to an increasing number of X-ALD patients diagnosed at risk for CCALD. Current follow-up in asymptomatic boys with X-ALD requires repetitive cerebral MRIs under sedation. A reliable and easily accessible biomarker that predicts CCALD would therefore be of great value. Here we report the application of targeted metabolomics by AbsoluteIDQ p180-Kit from Biocrates to search for suitable biomarkers in X-ALD. LysoPC a C20:3 and lysoPC a C20:4 were identified as metabolites that indicate neuroinflammation after induction of experimental autoimmune encephalitis in the serum of Abcd1tm1Kds mice. Analysis of serum from X-ALD patients also revealed different concentrations of these lipids at different disease stages. Further studies in a larger cohort of X-ALD patient sera are needed to prove the diagnostic value of these lipids for use as early biomarkers for neuroinflammation in CCALD patients.
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Affiliation(s)
- Matthias Kettwig
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Henry Klemp
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Stefan Nessler
- Institute of Neuropathology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Frank Streit
- Institute for Clinical Chemistry, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Ralph Krätzner
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Hendrik Rosewich
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
| | - Jutta Gärtner
- Department of Pediatrics and Adolescent Medicine, Division of Pediatric Neurology, University Medical Center Göttingen, Georg August University, Göttingen, Germany
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3
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Dwyer CM, Nguyen LTT, Healy LM, Dutta R, Ludwin S, Antel J, Binder MD, Kilpatrick TJ. Multiple Sclerosis as a Syndrome-Implications for Future Management. Front Neurol 2020; 11:784. [PMID: 32982904 PMCID: PMC7483755 DOI: 10.3389/fneur.2020.00784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 06/25/2020] [Indexed: 12/25/2022] Open
Abstract
We propose that multiple sclerosis (MS) is best characterized as a syndrome rather than a single disease because different pathogenetic mechanisms can result in the constellation of symptoms and signs by which MS is clinically characterized. We describe several cellular mechanisms that could generate inflammatory demyelination through disruption of homeostatic interactions between immune and neural cells. We illustrate that genomics is important in identifying phenocopies, in particular for primary progressive MS. We posit that molecular profiling, rather than traditional clinical phenotyping, will facilitate meaningful patient stratification, as illustrated by interactions between HLA and a regulator of homeostatic phagocytosis, MERTK. We envisage a personalized approach to MS management where genetic, molecular, and cellular information guides management.
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Affiliation(s)
- Christopher M Dwyer
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, VIC, Australia
| | - Linda Thien-Trang Nguyen
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia
| | - Luke M Healy
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Ranjan Dutta
- Department of Neurosciences, Cleveland Clinic Lerner College of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Samuel Ludwin
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Jack Antel
- Neuroimmunology Unit, Montreal Neurological Institute, Department of Neurology and Neurosurgery, McGill University, Montreal, QC, Canada
| | - Michele D Binder
- Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC, Australia
| | - Trevor J Kilpatrick
- Florey Institute of Neuroscience and Mental Health, Florey Department, The University of Melbourne, Parkville, VIC, Australia.,Department of Neurology, Royal Melbourne Hospital, Parkville, VIC, Australia
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4
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Ferreira BK, Rodrigues MT, Streck EL, Ferreira GC, Schuck PF. White matter disturbances in phenylketonuria: Possible underlying mechanisms. J Neurosci Res 2020; 99:349-360. [PMID: 32141105 DOI: 10.1002/jnr.24598] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2019] [Revised: 01/09/2020] [Accepted: 02/04/2020] [Indexed: 12/24/2022]
Abstract
White matter pathologies, as well as intellectual disability, microcephaly, and other central nervous system injuries, are clinical traits commonly ascribed to classic phenylketonuria (PKU). PKU is an inherited metabolic disease elicited by the deficiency of phenylalanine hydroxylase. Accumulation of l-phenylalanine (Phe) and its metabolites is found in tissues and body fluids in phenylketonuric patients. In order to mitigate the clinical findings, rigorous dietary Phe restriction constitutes the core of therapeutic management in PKU. Myelination is the process whereby the oligodendrocytes wrap myelin sheaths around the axons, supporting the conduction of action potentials. White matter injuries are implicated in the brain damage related to PKU, especially in untreated or poorly treated patients. The present review summarizes evidence toward putative mechanisms driving the white matter pathology in PKU patients.
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Affiliation(s)
- Bruna Klippel Ferreira
- Laboratório de Neuroenergética e Erros Inatos do Metabolismo, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Porto Alegre, Brazil
| | - Melissa Torres Rodrigues
- Laboratório de Erros Inatos do Metabolismo, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.,Programa de Pós-graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
| | - Emilio Luiz Streck
- Laboratório de Neurologia Experimental, Programa de Pós-Graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, Brazil
| | - Gustavo Costa Ferreira
- Laboratório de Neuroenergética e Erros Inatos do Metabolismo, Programa de Bioquímica e Biofísica Celular, Instituto de Bioquímica Médica Leopoldo de Meis, Universidade Federal do Rio de Janeiro, Porto Alegre, Brazil
| | - Patricia Fernanda Schuck
- Laboratório de Erros Inatos do Metabolismo, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil.,Programa de Pós-graduação em Biologia Celular e Molecular, Escola de Ciências da Saúde e da Vida, Pontifícia Universidade Católica do Rio Grande do Sul, Porto Alegre, Brazil
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Cisneros-Mejorado AJ, Garay E, Ortiz-Retana J, Concha L, Moctezuma JP, Romero S, Arellano RO. Demyelination-Remyelination of the Rat Caudal Cerebellar Peduncle Evaluated with Magnetic Resonance Imaging. Neuroscience 2019; 439:255-267. [PMID: 31299350 DOI: 10.1016/j.neuroscience.2019.06.042] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 06/14/2019] [Accepted: 06/28/2019] [Indexed: 01/20/2023]
Abstract
Remyelination is common under physiological conditions and usually occurs as a response to a pathological demyelinating event. Its potentiation is an important goal for the development of therapies against pathologies such as multiple sclerosis and white matter injury. Visualization and quantification in vivo of demyelination and remyelination processes are essential for longitudinal studies that will allow the testing and development of pro-myelinating strategies. In this study, ethidium bromide (EB) was stereotaxically injected into the caudal cerebellar peduncle (c.c.p.) in rats to produce demyelination; the resulting lesion was characterized (i) transversally through histology using Black-Gold II (BGII) staining, and (ii) longitudinally through diffusion-weighted magnetic resonance imaging (dMRI), by computing fractional anisotropy (FA) and diffusivity parameters to detect microstructural changes. Using this characterization, we evaluated, in the lesioned c.c.p., the effect of N-butyl-β-carboline-3-carboxylate (β-CCB), a potentiator of GABAergic signaling in oligodendrocytes. The dMRI analysis revealed significant changes in the anisotropic and diffusivity properties of the c.c.p. A decreased FA and increased radial diffusivity (λ⊥) were evident following c.c.p. lesioning. These changes correlated strongly with an apparent decrease in myelin content as evidenced by BGII. Daily systemic β-CCB administration for 2 weeks in lesioned animals increased FA and decreased λ⊥, suggesting an improvement in myelination, which was supported by histological analysis. This study shows that structural changes in the demyelination-remyelination of the caudal cerebellar peduncle (DRCCP) model can be monitored longitudinally by MRI, and it suggests that remyelination is enhanced by β-CCB treatment. This article is part of a Special Issue entitled: Honoring Ricardo Miledi - outstanding neuroscientist of XX-XXI centuries.
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Affiliation(s)
- Abraham J Cisneros-Mejorado
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Edith Garay
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Juan Ortiz-Retana
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Luis Concha
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Juan P Moctezuma
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Samuel Romero
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico
| | - Rogelio O Arellano
- Instituto de Neurobiología, Universidad Nacional Autónoma de México, Boulevard Juriquilla 3001, Juriquilla Querétaro, CP 76230, Querétaro, Mexico.
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Luca A, Calandra C, Luca M. Molecular Bases of Alzheimer's Disease and Neurodegeneration: The Role of Neuroglia. Aging Dis 2018; 9:1134-1152. [PMID: 30574424 PMCID: PMC6284765 DOI: 10.14336/ad.2018.0201] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Accepted: 02/01/2018] [Indexed: 12/13/2022] Open
Abstract
Neuroglia is an umbrella term indicating different cellular types that play a pivotal role in the brain, being involved in its development and functional homeostasis. Glial cells are becoming the focus of recent researches pertaining the pathogenesis of neurodegenerative disorders, Alzheimer's Disease (AD) in particular. In fact, activated microglia is the main determinant of neuroinflammation, contributing to neurodegeneration. In addition, the oxidative insult occurring during pathological brain aging can activate glial cells that, in turn, can favor the production of free radicals. Moreover, the recent Glycogen Synthase Kinase 3 (GSK-3) hypothesis of AD suggests that GSK3, involved in the regulation of glial cells functioning, could exert a role in amyloid deposition and tau hyper-phosphorylation. In this review, we briefly describe the main physiological functions of the glial cells and discuss the link between neuroglia and the most studied molecular bases of AD. In addition, we dedicate a section to the glial changes occurring in AD, with particular attention to their role in terms of neurodegeneration. In the light of the literature data, neuroglia could play a fundamental role in AD pathogenesis and progression. Further studies are needed to shed light on this topic.
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Affiliation(s)
- Antonina Luca
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University Hospital Policlinico-Vittorio Emanuele, Catania, 95100 Sicily, Italy
| | - Carmela Calandra
- Department of Medical and Surgical Sciences and Advanced Technologies “G.F. Ingrassia”, University Hospital Policlinico-Vittorio Emanuele, Catania, 95100 Sicily, Italy
| | - Maria Luca
- Department of General Surgery and Medical-Surgical Specialties, Dermatology Clinic, University Hospital Policlinico-Vittorio Emanuele, Catania, 95100 Sicily, Italy
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Stassart RM, Möbius W, Nave KA, Edgar JM. The Axon-Myelin Unit in Development and Degenerative Disease. Front Neurosci 2018; 12:467. [PMID: 30050403 PMCID: PMC6050401 DOI: 10.3389/fnins.2018.00467] [Citation(s) in RCA: 131] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Accepted: 06/19/2018] [Indexed: 12/15/2022] Open
Abstract
Axons are electrically excitable, cable-like neuronal processes that relay information between neurons within the nervous system and between neurons and peripheral target tissues. In the central and peripheral nervous systems, most axons over a critical diameter are enwrapped by myelin, which reduces internodal membrane capacitance and facilitates rapid conduction of electrical impulses. The spirally wrapped myelin sheath, which is an evolutionary specialisation of vertebrates, is produced by oligodendrocytes and Schwann cells; in most mammals myelination occurs during postnatal development and after axons have established connection with their targets. Myelin covers the vast majority of the axonal surface, influencing the axon's physical shape, the localisation of molecules on its membrane and the composition of the extracellular fluid (in the periaxonal space) that immerses it. Moreover, myelinating cells play a fundamental role in axonal support, at least in part by providing metabolic substrates to the underlying axon to fuel its energy requirements. The unique architecture of the myelinated axon, which is crucial to its function as a conduit over long distances, renders it particularly susceptible to injury and confers specific survival and maintenance requirements. In this review we will describe the normal morphology, ultrastructure and function of myelinated axons, and discuss how these change following disease, injury or experimental perturbation, with a particular focus on the role the myelinating cell plays in shaping and supporting the axon.
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Affiliation(s)
- Ruth M. Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Department of Neuropathology, University Medical Center Leipzig, Leipzig, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
| | - Julia M. Edgar
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, Germany
- Institute of Infection, Immunity and Inflammation, College of Medical Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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Sun J, Zhou H, Bai F, Zhang Z, Ren Q. Remyelination: A Potential Therapeutic Strategy for Alzheimer's Disease? J Alzheimers Dis 2018; 58:597-612. [PMID: 28453483 DOI: 10.3233/jad-170036] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Myelin is a lipid-rich multilamellar membrane that wraps around long segments of neuronal axons and it increases the conduction of action potentials, transports the necessary trophic support to the neuronal axons, and reduces the energy consumed by the neuronal axons. Together with axons, myelin is a prerequisite for the higher functions of the central nervous system and complex forms of network integration. Myelin impairments have been suggested to lead to neuronal dysfunction and cognitive decline. Accumulating evidence, including brain imaging and postmortem and genetic association studies, has implicated myelin impairments in Alzheimer's disease (AD). Increasing data link myelin impairments with amyloid-β (Aβ) plaques and tau hyperphosphorylation, which are both present in patients with AD. Moreover, aging and apolipoprotein E (ApoE) may be involved in the myelin impairments observed in patients with AD. Decreased neuronal activity, increased Aβ levels, and inflammation further damage myelin in patients with AD. Furthermore, treatments that promote myelination contribute to the recovery of neuronal function and improve cognition. Therefore, strategies targeting myelin impairment may provide therapeutic opportunities for patients with AD.
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9
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Novgorodov SA, Voltin JR, Gooz MA, Li L, Lemasters JJ, Gudz TI. Acid sphingomyelinase promotes mitochondrial dysfunction due to glutamate-induced regulated necrosis. J Lipid Res 2017; 59:312-329. [PMID: 29282302 DOI: 10.1194/jlr.m080374] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 12/05/2017] [Indexed: 12/11/2022] Open
Abstract
Inhibiting the glutamate/cystine antiporter system xc-, a key antioxidant defense machinery in the CNS, could trigger a novel form of regulated necrotic cell death, ferroptosis. The underlying mechanisms of system xc--dependent cell demise were elucidated using primary oligodendrocytes (OLs) treated with glutamate to block system xc- function. Pharmacological analysis revealed ferroptosis as a major contributing factor to glutamate-initiated OL death. A sphingolipid profile showed elevations of ceramide species and sphingosine that were preventable by inhibiting of an acid sphingomyelinase (ASM) activity. OL survival was enhanced by both downregulating ASM expression and blocking ASM activity. Glutamate-induced ASM activation seems to involve posttranscriptional mechanisms and was associated with a decreased GSH level. Further investigation of the mechanisms of OL response to glutamate revealed enhanced reactive oxygen species production, augmented lipid peroxidation, and opening of the mitochondrial permeability transition pore that were attenuated by hindering ASM. Of note, knocking down sirtuin 3, a deacetylase governing the mitochondrial antioxidant system, reduced OL survival. The data highlight the importance of the mitochondrial compartment in regulated necrotic cell death and accentuate the novel role of ASM in disturbing mitochondrial functions during OL response to glutamate toxicity, which is essential for pathobiology in stroke and traumatic brain injury.
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Affiliation(s)
- Sergei A Novgorodov
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Joshua R Voltin
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425
| | - Monika A Gooz
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - Li Li
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - John J Lemasters
- Departments of Drug Discovery, Medical University of South Carolina, Charleston, SC 29425
| | - Tatyana I Gudz
- Departments of Neuroscience Medical University of South Carolina, Charleston, SC 29425 .,Ralph H. Johnson Veterans Affairs Medical Center, Charleston, SC 29401
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10
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Leoni V, Nury T, Vejux A, Zarrouk A, Caccia C, Debbabi M, Fromont A, Sghaier R, Moreau T, Lizard G. Mitochondrial dysfunctions in 7-ketocholesterol-treated 158N oligodendrocytes without or with α-tocopherol: Impacts on the cellular profil of tricarboxylic cycle-associated organic acids, long chain saturated and unsaturated fatty acids, oxysterols, cholesterol and cholesterol precursors. J Steroid Biochem Mol Biol 2017; 169:96-110. [PMID: 27020660 DOI: 10.1016/j.jsbmb.2016.03.029] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2015] [Revised: 03/21/2016] [Accepted: 03/22/2016] [Indexed: 11/28/2022]
Abstract
In multiple sclerosis (MS) a process of white matter degradation leading to demyelination is observed. Oxidative stress, inflammation, apoptosis, necrosis and/or autophagy result together into a progressive loss of oligodendrocytes. 7-ketocholesterol (7KC), found increased in the cerebrospinal fluid of MS patients, triggers a rupture of RedOx homeostasis associated with mitochondrial dysfunctions, aptoptosis and autophagy (oxiapoptophagy) in cultured murine oligodendrocytes (158N). α-tocopherol is able to mild the alterations induced by 7KC partially restoring the cellular homeostasis. In presence of 7KC, the amount of adherent 158N cells was decreased and oxidative stress was enhanced. An increase of caspase-3 and PARP degradation (evidences of apoptosis), and an increased LC3-II/LC3-I ratio (criterion of autophagy), were detected. These events were associated with a decrease of the mitochondrial membrane potential (ΔΨm) and by a decrease of oxidative phosphorylation revealed by reduced NAD+ and ATP. The cellular lactate was higher while pyruvate, citrate, fumarate, succinate (tricarboxylic acid (TCA) cycle intermediates) were significantly reduced in exposed cells, suggesting that an impairment of mitochondrial respiratory functions could lead to an increase of lactate production and to a reduced amount of ATP and acetyl-CoA available for the anabolic pathways. The concentration of sterol precursors lathosterol, lanosterol and desmosterol were significantly reduced together with satured and unsatured long chain fatty acids (C16:0 - C18:0, structural elements of membrane phospholipids). Such reductions were milder with α-tocopherol. It is likely that the cell death induced by 7KC is associated with mitochondrial dysfunctions, including alterations of oxidative phosphorylation, which could result from lipid anabolism dysfunctions, especially on TCA cycle intermediates. A better knowledge of mitochondrial associated dysfunctions triggered by 7KC will contribute to bring new information on the demyelination processes which are linked with oxidative stress and lipid peroxidation, especially in MS.
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Affiliation(s)
- Valerio Leoni
- Laboratory of Clinical Chemistry, Hospital of Varese, ASST-Settelaghi, Varese, Italy; Laboratory of Clinical Pathology, Foundation IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.
| | - Thomas Nury
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France
| | - Anne Vejux
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France
| | - Amira Zarrouk
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia
| | - Claudio Caccia
- Laboratory of Clinical Pathology, Foundation IRCCS Istituto Neurologico Carlo Besta, Milan, Italy
| | - Meryam Debbabi
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia
| | - Agnès Fromont
- Department of Neurology, Univ. Hospital/Univ. Bourgogne Franche Comté, Dijon, France
| | - Randa Sghaier
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France; Univ. Monastir, Faculty of Medicine, LR12ES05, Lab-NAFS 'Nutrition - Functional Food & Vascular Health', Monastir, & Univ. Sousse, Faculty of Medicine, Sousse, Tunisia
| | - Thibault Moreau
- Department of Neurology, Univ. Hospital/Univ. Bourgogne Franche Comté, Dijon, France
| | - Gérard Lizard
- Biochemistry of the Peroxisome, Inflammation and Lipid Metabolism' EA 7270/Univ. Bourgogne Franche Comté/INSERM, Dijon, France.
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Chi L, Belardinelli L, Zeng A, Hirakawa R, Rajamani S, Ling H, Dhalla AK. Inhibition of late Na+ current, a novel target to improve diastolic function and electrical abnormalities in Dahl salt-sensitive rats. Am J Physiol Heart Circ Physiol 2016; 310:H1313-20. [PMID: 26993228 DOI: 10.1152/ajpheart.00863.2015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 03/11/2016] [Indexed: 12/19/2022]
Abstract
Late Na(+) current (INaL) is enhanced in myocytes of animals with chronic heart failure and patients with hypertrophic cardiomyopathy. To define the role of INaL in diastolic heart failure, the effects of GS-458967 (GS-967), a potent INaL inhibitor on mechanical and electrical abnormalities, were determined in an animal model of diastolic dysfunction. Dahl salt-sensitive (DSS) rats fed a high-salt (HS) diet for 8 wk, compared with a normal salt (NS) diet, had increased left ventricular (LV) mass (1,257 ± 96 vs. 891 ± 34 mg) and diastolic dysfunction [isovolumic relaxation time (IVRT): 26.8 ± 0.5 vs. 18.9 ± 0.2 ms; early transmitral flow velocity/early mitral annulus velocity (E/E') ratio: 25.5 ± 1.9 vs. 14.9 ± 0.9]. INaL in LV myocytes from HS rats was significantly increased to 0.41 ± 0.02 from 0.14 ± 0.02 pA/pF in NS rats. The action potential duration (APD) was prolonged to 136 ± 12 from 68 ± 9 ms in NS rats. QTc intervals were longer in HS vs. NS rats (267 ± 8 vs. 212 ± 2 ms). Acute and chronic treatment with GS-967 decreased the enhanced INaL to 0.24 ± 0.01 and 0.17 ± 0.02 pA/pF, respectively, vs. 0.41 ± 0.02 pA/pF in the HS group. Chronic treatment with GS-967 dose-dependently reduced LV mass, the increases in E/E' ratio, and the prolongation of IVRT by 27, 27, and 20%, respectively, at the 1.0 mg·kg(-1)·day(-1) dose without affecting blood pressure or LV systolic function. The prolonged APDs in myocytes and QTc of HS rats were significantly reduced with GS-967 treatment. These results indicate that INaL is a significant contributor to the LV diastolic dysfunction, hypertrophy, and repolarization abnormalities and thus, inhibition of this current is a promising therapeutic target for diastolic heart failure.
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Affiliation(s)
- Liguo Chi
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Luiz Belardinelli
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Aliya Zeng
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Ryoko Hirakawa
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Sridharan Rajamani
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Haiyun Ling
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
| | - Arvinder K Dhalla
- Department of Cardiovascular Biology, Gilead Sciences, Fremont, California
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12
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Sandoval-Hernández A, Contreras MJ, Jaramillo J, Arboleda G. Regulation of Oligodendrocyte Differentiation and Myelination by Nuclear Receptors: Role in Neurodegenerative Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 949:287-310. [DOI: 10.1007/978-3-319-40764-7_14] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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13
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Berger J, Dorninger F, Forss-Petter S, Kunze M. Peroxisomes in brain development and function. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1863:934-55. [PMID: 26686055 PMCID: PMC4880039 DOI: 10.1016/j.bbamcr.2015.12.005] [Citation(s) in RCA: 117] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2015] [Revised: 12/04/2015] [Accepted: 12/09/2015] [Indexed: 12/26/2022]
Abstract
Peroxisomes contain numerous enzymatic activities that are important for mammalian physiology. Patients lacking either all peroxisomal functions or a single enzyme or transporter function typically develop severe neurological deficits, which originate from aberrant development of the brain, demyelination and loss of axonal integrity, neuroinflammation or other neurodegenerative processes. Whilst correlating peroxisomal properties with a compilation of pathologies observed in human patients and mouse models lacking all or individual peroxisomal functions, we discuss the importance of peroxisomal metabolites and tissue- and cell type-specific contributions to the observed brain pathologies. This enables us to deconstruct the local and systemic contribution of individual metabolic pathways to specific brain functions. We also review the recently discovered variability of pathological symptoms in cases with unexpectedly mild presentation of peroxisome biogenesis disorders. Finally, we explore the emerging evidence linking peroxisomes to more common neurological disorders such as Alzheimer’s disease, autism and amyotrophic lateral sclerosis. This article is part of a Special Issue entitled: Peroxisomes edited by Ralf Erdmann.
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Affiliation(s)
- Johannes Berger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria.
| | - Fabian Dorninger
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria.
| | - Sonja Forss-Petter
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria.
| | - Markus Kunze
- Department of Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, 1090 Vienna, Austria.
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14
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Coggan JS, Bittner S, Stiefel KM, Meuth SG, Prescott SA. Physiological Dynamics in Demyelinating Diseases: Unraveling Complex Relationships through Computer Modeling. Int J Mol Sci 2015; 16:21215-36. [PMID: 26370960 PMCID: PMC4613250 DOI: 10.3390/ijms160921215] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Revised: 08/21/2015] [Accepted: 08/25/2015] [Indexed: 11/16/2022] Open
Abstract
Despite intense research, few treatments are available for most neurological disorders. Demyelinating diseases are no exception. This is perhaps not surprising considering the multifactorial nature of these diseases, which involve complex interactions between immune system cells, glia and neurons. In the case of multiple sclerosis, for example, there is no unanimity among researchers about the cause or even which system or cell type could be ground zero. This situation precludes the development and strategic application of mechanism-based therapies. We will discuss how computational modeling applied to questions at different biological levels can help link together disparate observations and decipher complex mechanisms whose solutions are not amenable to simple reductionism. By making testable predictions and revealing critical gaps in existing knowledge, such models can help direct research and will provide a rigorous framework in which to integrate new data as they are collected. Nowadays, there is no shortage of data; the challenge is to make sense of it all. In that respect, computational modeling is an invaluable tool that could, ultimately, transform how we understand, diagnose, and treat demyelinating diseases.
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Affiliation(s)
- Jay S Coggan
- NeuroLinx Research Institute, La Jolla, CA 92039, USA.
| | - Stefan Bittner
- Department of Neurology, Institute of Physiology, Universitätsklinikum Münster, 48149 Münster, Germany.
| | | | - Sven G Meuth
- Department of Neurology, Institute of Physiology, Universitätsklinikum Münster, 48149 Münster, Germany.
| | - Steven A Prescott
- Neurosciences and Mental Health, the Hospital for Sick Children, Toronto, ON M5G 1X8, Canada.
- Department of Physiology and the Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5G 1X8, Canada.
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15
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Stefanova NA, Maksimova KY, Kiseleva E, Rudnitskaya EA, Muraleva NA, Kolosova NG. Melatonin attenuates impairments of structural hippocampal neuroplasticity in OXYS rats during active progression of Alzheimer's disease-like pathology. J Pineal Res 2015; 59:163-77. [PMID: 25988948 DOI: 10.1111/jpi.12248] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 05/08/2015] [Indexed: 12/17/2022]
Abstract
Translational research on Alzheimer's disease (AD) has often focused on reducing the high cerebral levels of amyloid-β (Aβ) as a key characteristic of AD pathogenesis. There is, however, a growing body of evidence that synaptic dysfunction may be crucial for the development of the most common (sporadic) form of AD. The applicability of melatonin (mainly produced by the pineal gland) to the treatment of AD is actively evaluated, but usually, such studies are based on animal models of early-onset AD, which is responsible for only ~5% of AD cases. We have shown previously that in OXYS rats (an established model of sporadic AD), accumulation of toxic forms of Aβ in the brain occurs later than does the development of signs of neurodegenerative changes and synaptic failure. In this regard, recently, we uncovered beneficial neuroprotective effects of melatonin (prophylactic dietary supplementation) in OXYS rats. Our aim here was to evaluate, starting at the age of active progression of AD-like pathology in OXYS rats, the effects of long-term oral administration of melatonin on the structure of synapses and on neuronal and glial cells of the hippocampus. Melatonin significantly increased hippocampal synaptic density and the number of excitatory synapses, decreased the number of inhibitory synapses, and upregulated pre- and postsynaptic proteins (synapsin I and PSD-95, respectively). Furthermore, melatonin improved the ultrastructure of neuronal and glial cells and reduced glial density. Based on our past and present results, the repair of neuroplasticity by melatonin is a promising strategy against AD.
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Affiliation(s)
| | | | | | | | | | - Nataliya G Kolosova
- Institute of Cytology and Genetics, Novosibirsk, Russia
- Novosibirsk State University, Novosibirsk, Russia
- Institute of Mitoengineering, Moscow, Russia
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16
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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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17
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Barrette B, Nave KA, Edgar JM. Molecular triggers of neuroinflammation in mouse models of demyelinating diseases. Biol Chem 2014; 394:1571-81. [PMID: 23959664 DOI: 10.1515/hsz-2013-0219] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 08/15/2013] [Indexed: 12/20/2022]
Abstract
Myelinating cells wrap axons with multi-layered myelin sheaths for rapid impulse propagation. Dysfunctions of oligodendrocytes or Schwann cells are often associated with neuroinflammation, as observed in animal models of leukodystrophies and peripheral neuropathies, respectively. The neuroinflammatory response modulates the pathological changes, including demyelination and axonal injury, but also remyelination and repair. Here we discuss different immune mechanisms as well as factors released or exposed by myelinating glia in disease conditions. The spectrum of inflammatory mediators varies with different myelin disorders and has a major impact on the beneficial or detrimental role of immune cells in keeping nervous system integrity.
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18
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Kumar R, Pham TT, Macey PM, Woo MA, Yan-Go FL, Harper RM. Abnormal myelin and axonal integrity in recently diagnosed patients with obstructive sleep apnea. Sleep 2014; 37:723-32. [PMID: 24899761 DOI: 10.5665/sleep.3578] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
STUDY OBJECTIVES Patients with obstructive sleep apnea (OSA) show significant white matter injury; whether that injury represents myelin or axonal damage is unclear. The objective was to examine myelin and axonal changes in patients with newly diagnosed OSA over control subjects. DESIGN Cross-sectional study. SETTING University-based medical center. PARTICIPANTS Twenty-three newly-diagnosed, treatment-naïve OSA and 23 age- and sex-matched control subjects. INTERVENTIONS None. MEASUREMENTS AND RESULTS Radial and axial diffusivity maps, calculated from diffusion tensor imaging data (3.0 Tesla MRI scanner), indicating diffusion perpendicular (myelin status) or parallel (axonal status) to fibers, respectively, were normalized, smoothed, and compared between groups (analysis of covariance; covariate: age). Global brain radial and axial diffusivity values, and global brain volume with myelin and axonal changes were determined, and region-of-interest analyses performed in areas of significant differences between groups based on voxel-based procedures. Global radial and axial diffusivity values were significantly reduced in OSA versus control subjects (radial, P = 0.004; axial, P = 0.019), with radial (myelin) diffusivity reduced more than axial (axonal), and more left-sided reduction for both measures. Localized declines for myelin and axonal measures appeared in the dorsal and ventral medulla, cerebellar cortex and deep nuclei, basal ganglia, hippocampus, amygdala, corpus callosum, insula, cingulate and medial frontal cortices, and other cortical areas (P < 0.005), all regions mediating functions affected in OSA. CONCLUSIONS Fiber injury appears in critical medullary respiratory regulatory sites, as well as cognitive and autonomic control areas. Myelin is more affected in newly diagnosed OSA than axons, and primarily on the left side, possibly from the increased myelin sensitivity to hypoxia and asymmetric perfusion.
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Affiliation(s)
- Rajesh Kumar
- Department of Anesthesiology ; Department of Radiological Sciences ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA
| | - Tiffany T Pham
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Paul M Macey
- UCLA School of Nursing, Los Angeles, CA ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA
| | | | - Frisca L Yan-Go
- Department of Neurology, David Geffen School of Medicine at UCLA, Los Angeles, CA
| | - Ronald M Harper
- Department of Neurobiology, David Geffen School of Medicine at UCLA, Los Angeles, CA ; The Brain Research Institute, University of California at Los Angeles, Los Angeles, CA
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Berger J, Forss-Petter S, Eichler FS. Pathophysiology of X-linked adrenoleukodystrophy. Biochimie 2013; 98:135-42. [PMID: 24316281 PMCID: PMC3988840 DOI: 10.1016/j.biochi.2013.11.023] [Citation(s) in RCA: 134] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2013] [Accepted: 11/22/2013] [Indexed: 12/26/2022]
Abstract
Currently the molecular basis for the clinical heterogeneity of X-linked adrenoleukodystrophy (X-ALD) is poorly understood. The genetic bases for all different phenotypic variants of X-ALD are mutations in the gene encoding the peroxisomal ATP-binding cassette (ABC) transporter, ABCD1 (formerly adrenoleukodystrophy protein, ALDP). ABCD1 transports CoA-activated very long-chain fatty acids from the cytosol into the peroxisome for degradation. The phenotypic variability is remarkable ranging from cerebral inflammatory demyelination of childhood onset, leading to death within a few years, to adults remaining pre-symptomatic through more than five decades. There is no general genotype–phenotype correlation in X-ALD. The default manifestation of mutations in ABCD1 is adrenomyeloneuropathy, a slowly progressive dying-back axonopathy affecting both ascending and descending spinal cord tracts as well as in some cases, a peripheral neuropathy. In about 60% of male X-ALD patients, either in childhood (35–40%) or in adulthood (20%), an initial, clinically silent, myelin destabilization results in conversion to a devastating, rapidly progressive form of cerebral inflammatory demyelination. Here, ABCD1 remains a susceptibility gene, necessary but not sufficient for inflammatory demyelination to occur. Although the accumulation of very long-chain fatty acids appears to be essential for the pathomechanism of all phenotypes, the molecular mechanisms underlying these phenotypes are fundamentally different. Cell autonomous processes such as oxidative stress and energy shortage in axons as well as non-cell autonomous processes involving axon–glial interactions seem pertinent to the dying-back axonopathy. Various dynamic mechanisms may underlie the initiation of inflammation, the altered immune reactivity, the propagation of inflammation, as well as the mechanisms leading to the arrest of inflammation after hematopoietic stem cell transplantation. An improved understanding of the molecular mechanisms involved in these events is required for the development of urgently needed therapeutics. Adrenomyeloneuropathy (AMN) is proposed to be the core syndrome of X-ALD. The cerebral inflammatory demyelinating form of X-ALD is independent of AMN. The same genetic basis but fundamentally different pathomechanisms lead to AMN and cerebral ALD. Genetic, epigenetic and environmental factors modulate onset and severity of AMN and cerebral ALD.
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Affiliation(s)
- J Berger
- Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria.
| | - S Forss-Petter
- Pathobiology of the Nervous System, Center for Brain Research, Medical University of Vienna, Spitalgasse 4, A-1090 Vienna, Austria
| | - F S Eichler
- Department for Neurology, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street ACC 708, Boston, MA 02114, USA
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20
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Kassmann CM. Myelin peroxisomes - essential organelles for the maintenance of white matter in the nervous system. Biochimie 2013; 98:111-8. [PMID: 24120688 DOI: 10.1016/j.biochi.2013.09.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 09/20/2013] [Indexed: 12/29/2022]
Abstract
Peroxisomes are cellular compartments primarily associated with lipid metabolism. Most cell types, including nervous system cells, harbor several hundred of these organelles. The importance of peroxisomes for central nervous system white matter is evidenced by a variety of human peroxisomal disorders with neurological impairment frequently involving the white matter. Moreover, the most frequent childhood white matter disease, X-linked adrenoleukodystrophy, is a peroxisomal disorder. During the past decade advances in imaging techniques have enabled the identification of peroxisomes within the myelin sheath, especially close to nodes of Ranvier. Although the function of myelin peroxisomes is not solved yet on molecular level, recently acquired knowledge suggests a central role for these organelles in axo-glial metabolism. This review focuses on the biology of myelin peroxisomes as well as on the pathology of myelin and myelinated axons that is observed as a consequence of partial or complete peroxisomal dysfunction in the brain.
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Affiliation(s)
- Celia M Kassmann
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Hermann-Rein-Straße 3, 37075 Göttingen, Germany.
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21
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Vamecq J, Cherkaoui-Malki M, Andreoletti P, Latruffe N. The human peroxisome in health and disease: the story of an oddity becoming a vital organelle. Biochimie 2013; 98:4-15. [PMID: 24075875 DOI: 10.1016/j.biochi.2013.09.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Accepted: 09/18/2013] [Indexed: 12/18/2022]
Abstract
Since the first report by Rhodin in 1954, our knowledge on mammalian microbodies/peroxisomes has known several periods. An initial two decades period (1954-1973) has contributed to the biochemical individualisation of peroxisomes as a new class of subcellular organelles (de Duve, 1965). The corresponding research period failed to define a clear role of mammalian peroxisomes in vital functions and intermediary metabolism, explaining why feeling that peroxisomes might be in the human cell oddities has prevailed during several decades. The period standing from 1973 to nowadays has progressively removed this cell oddity view of peroxisomes by highlighting vital function and metabolic role of peroxisomes in health and disease along with genetic and metabolic regulation of peroxisomal protein content, organelle envelope formation and protein signal targeting mechanisms. Research on peroxisomes and their response to various drugs and metabolites, dietary and physiological conditions has also played a key role in the discovery of peroxisome proliferator activated receptors (PPARs) belonging to the nuclear hormone receptor superfamily and for which impact in science and medicine goes now by far beyond that of the peroxisomes.
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Affiliation(s)
- Joseph Vamecq
- INSERM, Laboratory of Biochemistry and Molecular Biology, Hormonology-Metabolism-Nutrition-Oncology, Centre of Biology and Pathology (CBP), CHU Lille, France.
| | - Mustapha Cherkaoui-Malki
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
| | - Pierre Andreoletti
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
| | - Norbert Latruffe
- Laboratory of Biochemistry of Peroxisome, Inflammation & Lipids Metabolism (BioPeroxIL-EA7270), University of Burgundy, 21000 Dijon, France
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Abstract
Although myelination largely occurs during early postnatal life, myelinating oligodendrocytes are still generated in the adult brain. Myelin turnover in the adult is necessary for proper neuronal function and is gravely compromised in myelin disorders. The lineage relationship between adult neural stem cells and adult-born oligodendrocytes has been clarified, highlighting molecular pathways that could potentially be targeted to favour de novo myelination in pathological situations.
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Morita M, Shinbo S, Asahi A, Imanaka T. Very long chain fatty acid β-oxidation in astrocytes: contribution of the ABCD1-dependent and -independent pathways. Biol Pharm Bull 2013; 35:1972-9. [PMID: 23123468 DOI: 10.1248/bpb.b12-00411] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Very long chain fatty acid (VLCFA) metabolism in astrocytes is important for the maintenance of myelin structure in central nervous system. To analyze the contribution of the ABCD1-dependent and -independent pathways to VLCFA metabolism in astrocytes, we prepared human glioblastoma U87 cells with a silencing of ABCD1 and primary astrocytes from abcd1-deficient mice, and measured fatty acid β-oxidation in the presence or absence of a potent inhibitor of carnitine palmitoyltransferase I, 2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA). In U87 cells, C24:0 β-oxidation was decreased to ca. 70% of the control in the presence of POCA, and the activity was further decreased to ca. 20% by the silencing of ABCD1. In mouse primary astrocytes, C24:0 β-oxidation was also decreased to ca. 70% of the control in the presence of POCA. The C24:0 β-oxidation in Abcd1-deficient primary astrocytes was ca. 60% of the wild-type cells and the activity was further decreased to ca. 25% in the presence of POCA. Compared to human skin fibroblasts, in which VLCFA β-oxidation is not significantly inhibited by POCA, approximately one-third of the overall VLCFA β-oxidation was inhibited in both types of astrocytic cells. These results suggest that VLCFA is indeed β-oxidized in ABCD1-dependent pathway, but the ABCD1-independent peroxisomal and mitochondrial β-oxidation pathways significantly contribute to VLCFA β-oxidation in astrocytic cells.
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Affiliation(s)
- Masashi Morita
- Department of Biological Chemistry, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama 930–0194, Japan.
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Rüb U, Schöls L, Paulson H, Auburger G, Kermer P, Jen JC, Seidel K, Korf HW, Deller T. Clinical features, neurogenetics and neuropathology of the polyglutamine spinocerebellar ataxias type 1, 2, 3, 6 and 7. Prog Neurobiol 2013; 104:38-66. [PMID: 23438480 DOI: 10.1016/j.pneurobio.2013.01.001] [Citation(s) in RCA: 228] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Revised: 01/22/2013] [Accepted: 01/31/2013] [Indexed: 12/18/2022]
Abstract
The spinocerebellar ataxias type 1 (SCA1), 2 (SCA2), 3 (SCA3), 6 (SCA6) and 7 (SCA7) are genetically defined autosomal dominantly inherited progressive cerebellar ataxias (ADCAs). They belong to the group of CAG-repeat or polyglutamine diseases and share pathologically expanded and meiotically unstable glutamine-encoding CAG-repeats at distinct gene loci encoding elongated polyglutamine stretches in the disease proteins. In recent years, progress has been made in the understanding of the pathogenesis of these currently incurable diseases: Identification of underlying genetic mechanisms made it possible to classify the different ADCAs and to define their clinical and pathological features. Furthermore, advances in molecular biology yielded new insights into the physiological and pathophysiological role of the gene products of SCA1, SCA2, SCA3, SCA6 and SCA7 (i.e. ataxin-1, ataxin-2, ataxin-3, α-1A subunit of the P/Q type voltage-dependent calcium channel, ataxin-7). In the present review we summarize our current knowledge about the polyglutamine ataxias SCA1, SCA2, SCA3, SCA6 and SCA7 and compare their clinical and electrophysiological features, genetic and molecular biological background, as well as their brain pathologies. Furthermore, we provide an overview of the structure, interactions and functions of the different disease proteins. On the basis of these comprehensive data, similarities, differences and possible disease mechanisms are discussed.
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Affiliation(s)
- Udo Rüb
- Dr. Senckenberg Chronomedical Institute, Goethe-University, Theodor-Stern-Kai 7, D-60590 Frankfurt/Main, Germany.
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Building biocompatible hydrogels for tissue engineering of the brain and spinal cord. J Funct Biomater 2012; 3:839-63. [PMID: 24955749 PMCID: PMC4030922 DOI: 10.3390/jfb3040839] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 10/24/2012] [Indexed: 01/07/2023] Open
Abstract
Tissue engineering strategies employing biomaterials have made great progress in the last few decades. However, the tissues of the brain and spinal cord pose unique challenges due to a separate immune system and their nature as soft tissue. Because of this, neural tissue engineering for the brain and spinal cord may require re-establishing biocompatibility and functionality of biomaterials that have previously been successful for tissue engineering in the body. The goal of this review is to briefly describe the distinctive properties of the central nervous system, specifically the neuroimmune response, and to describe the factors which contribute to building polymer hydrogels compatible with this tissue. These factors include polymer chemistry, polymerization and degradation, and the physical and mechanical properties of the hydrogel. By understanding the necessities in making hydrogels biocompatible with tissue of the brain and spinal cord, tissue engineers can then functionalize these materials for repairing and replacing tissue in the central nervous system.
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Kemp S, Berger J, Aubourg P. X-linked adrenoleukodystrophy: Clinical, metabolic, genetic and pathophysiological aspects. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1465-74. [DOI: 10.1016/j.bbadis.2012.03.012] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Revised: 03/08/2012] [Accepted: 03/20/2012] [Indexed: 12/28/2022]
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Kumar R, Chavez AS, Macey PM, Woo MA, Yan-Go FL, Harper RM. Altered global and regional brain mean diffusivity in patients with obstructive sleep apnea. J Neurosci Res 2012; 90:2043-52. [PMID: 22715089 DOI: 10.1002/jnr.23083] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 03/27/2012] [Accepted: 04/13/2012] [Indexed: 12/30/2022]
Abstract
Obstructive sleep apnea (OSA) is a common and progressive disorder accompanied by severe cardiovascular and neuropsychological sequelae, presumably induced by brain injury resulting from the intermittent hypoxia and cardiovascular processes accompanying the syndrome. However, whether the predominant brain tissue pathology is acute or chronic in newly-diagnosed, untreated OSA subjects is unclear; this assessment is essential for revealing pathological processes. Diffusion tensor imaging (DTI)-based mean diffusivity (MD) procedures can detect and differentiate acute from chronic pathology and may be useful to reveal processes in the condition. We collected four DTI series from 23 newly-diagnosed, treatment-naïve OSA and 23 control subjects, using a 3.0-Tesla magnetic resonance imaging scanner. Mean diffusivity maps were calculated from each series, realigned, averaged, normalized to a common space, and smoothed. Global brain MD values for each subject were calculated using normalized MD maps and a global brain mask. Mean global brain MD values and smoothed MD maps were compared between groups by using analysis of covariance (covariate: age). Mean global brain MD values were significantly reduced in OSA compared with controls (P = 0.01). Multiple brain sites in OSA, including medullary, cerebellar, basal ganglia, prefrontal and frontal, limbic, insular, cingulum bundle, external capsule, corpus callosum, temporal, occipital, and corona radiata regions showed reduced regional MD values compared with controls. The results suggest that global brain MD values are significantly reduced in OSA, with certain regional sites especially affected, presumably a consequence of axonal, glial, and other cell changes in those areas. The findings likely represent acute pathological processes in newly-diagnosed OSA subjects.
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Affiliation(s)
- Rajesh Kumar
- Department of Neurobiology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, Los Angeles, California, USA
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ER Stress, Mitochondrial Dysfunction and Calpain/JNK Activation are Involved in Oligodendrocyte Precursor Cell Death by Unconjugated Bilirubin. Neuromolecular Med 2012; 14:285-302. [DOI: 10.1007/s12017-012-8187-9] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Accepted: 06/01/2012] [Indexed: 12/24/2022]
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Morita M, Imanaka T. Peroxisomal ABC transporters: structure, function and role in disease. Biochim Biophys Acta Mol Basis Dis 2012; 1822:1387-96. [PMID: 22366764 DOI: 10.1016/j.bbadis.2012.02.009] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2011] [Revised: 01/07/2012] [Accepted: 02/08/2012] [Indexed: 12/20/2022]
Abstract
ATP-binding cassette (ABC) transporters belong to one of the largest families of membrane proteins, and are present in almost all living organisms from eubacteria to mammals. They exist on plasma membranes and intracellular compartments such as the mitochondria, peroxisomes, endoplasmic reticulum, Golgi apparatus and lysosomes, and mediate the active transport of a wide variety of substrates in a variety of different cellular processes. These include the transport of amino acids, polysaccharides, peptides, lipids and xenobiotics, including drugs and toxins. Three ABC transporters belonging to subfamily D have been identified in mammalian peroxisomes. The ABC transporters are half-size and assemble mostly as a homodimer after posttranslational transport to peroxisomal membranes. ABCD1/ALDP and ABCD2/ALDRP are suggested to be involved in the transport of very long chain acyl-CoA with differences in substrate specificity, and ABCD3/PMP70 is involved in the transport of long and branched chain acyl-CoA. ABCD1 is known to be responsible for X-linked adrenoleukodystrophy (X-ALD), an inborn error of peroxisomal β-oxidation of very long chain fatty acids. Here, we summarize recent advances and important points in our advancing understanding of how these ABC transporters target and assemble to peroxisomal membranes and perform their functions in physiological and pathological processes, including the neurodegenerative disease, X-ALD.
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Affiliation(s)
- Masashi Morita
- Department of Biological Chemistry, University of Toyama, Toyama, Japan
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Deosaran E, Larsen KB, Hua R, Sargent G, Wang Y, Kim S, Lamark T, Jauregui M, Law K, Lippincott-Schwartz J, Brech A, Johansen T, Kim PK. NBR1 acts as an autophagy receptor for peroxisomes. J Cell Sci 2012; 126:939-52. [DOI: 10.1242/jcs.114819] [Citation(s) in RCA: 245] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Selective macro-autophagy is an intracellular process by which large cytoplasmic materials are selectively sequestered and degraded in the lysosomes. Substrate selection is mediated by ubiquitination and recruitment of ubiquitin-binding autophagic receptors such as p62, NBR1, NDP52 and Optineurin. Although it has been shown that these receptors act cooperatively to target some types of substrates to nascent autophagosomes, their precise roles are not well understood. Here, we examined selective autophagic degradation of peroxisomes (pexophagy), and found that NBR1 is necessary and sufficient for pexophagy. Mutagenesis studies of NBR1 showed that the amphipathic α-helical J domain, the ubiquitin-associated (UBA) domain, the LC3 interacting region and the coiled-coil domain are necessary to mediate pexophagy. Strikingly, substrate selectivity is partly achieved by NBR1 itself by coincident binding of the J and UBA domains to peroxisomes. Although p62 is not required when NBR1 is in excess, its binding to NBR1 increases the efficiency of NBR1 mediated pexophagy. Together, these results suggest that NBR1 is the specific autophagy receptor for pexophagy.
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Peroxisome proliferator-activated receptor γ agonists accelerate oligodendrocyte maturation and influence mitochondrial functions and oscillatory Ca(2+) waves. J Neuropathol Exp Neurol 2011; 70:900-12. [PMID: 21937914 DOI: 10.1097/nen.0b013e3182309ab1] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
We have previously shown that natural (15-deoxy-Δ-prostaglandin J2) and synthetic (pioglitazone) agonists of peroxisome proliferator-activated receptor γ (PPAR-γ) strengthen the intrinsic cellular mechanisms protecting oligodendrocyte (OL) progenitors (OPs) from oxidative insults and promote their differentiation. Here, we demonstrate that repeated administrations of PPAR-γ agonists to OP cultures accelerate their differentiation to OLs, as indicated by increased numbers of O4- and O1-positive cells that show increased myelin basic protein expression, elaborated cholesterol-enrichedmembranes and have increased peroxisomes. Moreover, PPAR-γ agonist-treated OLs show increased activity of the mitochondrial respiratory chain Complex IV and an increased ability to respond to environmental signals, such as adenosine diphosphate (ADP), with oscillatory Ca waves; the latter closely correlated with the presence of mitochondria and were inhibited by the mitochondrial respiratory chain Complex I inhibitor rotenone. Because Ca oscillations and mitochondrial respiratory chain activity play crucial roles in OL differentiation, these findings suggest that PPAR-γ agonists could protect OLs and promote myelination through several mechanisms, including those involving mitochondrial functions. Our studies support the therapeutic potential of PPAR-γ agonists in brain diseases in which mitochondrial alteration, oxidative stress, and demyelination occur and point to the need for a better understanding of the role of PPAR-γ and its agonists in OL biology.
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Agarwal A, Dibaj P, Kassmann CM, Goebbels S, Nave KA, Schwab MH. In vivo imaging and noninvasive ablation of pyramidal neurons in adult NEX-CreERT2 mice. ACTA ACUST UNITED AC 2011; 22:1473-86. [PMID: 21880656 DOI: 10.1093/cercor/bhr214] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
To study the function of individual neurons that are embedded in a complex neural network is difficult in mice. Conditional mutagenesis permits the spatiotemporal control of gene expression including the ablation of cells by toxins. To direct expression of a tamoxifen-inducible variant of Cre recombinase (CreERT2) selectively to cortical neurons, we replaced the coding region of the murine Nex1 gene by CreERT2 cDNA via homologous recombination in embryonic stem cells. When injected with tamoxifen, adult NEX-CreERT2 mice induced reporter gene expression exclusively in projection neurons of the neocortex and hippocampus. By titrating the tamoxifen dosage, we achieved recombination in single cells, which allowed multiphoton imaging of neocortical neurons in live mice. When hippocampal projection neurons were genetically ablated by induced expression of diphteria toxin, within 20 days the inflammatory response included the infiltration of CD3+ T cells. This marks a striking difference from similar studies, in which dying oligodendrocytes failed to recruit cells of the adaptive immune system.
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Affiliation(s)
- Amit Agarwal
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, 37075 Goettingen, Germany
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Ex vivo diffusion tensor imaging and neuropathological correlation in a murine model of hypoxia-ischemia-induced thrombotic stroke. J Cereb Blood Flow Metab 2011; 31:1155-69. [PMID: 21139628 PMCID: PMC3070976 DOI: 10.1038/jcbfm.2010.212] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Diffusion tensor imaging (DTI) is a powerful method to visualize white matter, but its use in patients with acute stroke remains limited because of the lack of corresponding histologic information. In this study, we addressed this issue using a hypoxia-ischemia (HI)-induced thrombotic model of stroke in adult mice. At 6, 15, and 24 hours after injury, animals were divided into three groups for (1) in vivo T2- and diffusion-weighted magnetic resonance imaging, followed by histochemistry, (2) ex vivo DTI and electron microscopy, and (3) additional biochemical or immunochemical assays. The temporal changes of diffusion anisotropy and histopathology were compared in the fimbria, internal capsule, and external capsule. We found that HI caused a rapid reduction of axial and radial diffusivities in all three axonal bundles. A large decrease in fractional anisotropy, but not in axial diffusivity per se, was associated with structural breakdown of axons. Furthermore, the decrease in radial diffusivity correlated with swelling of myelin sheaths and compression of the axoplasma. The gray matter of the hippocampus also exhibited a high level of diffusion anisotropy, and its reduction signified dendritic degeneration. Taken together, these results suggest that cross-evaluation of multiple DTI parameters may provide a fuller picture of axonal and dendritic injury in acute ischemic stroke.
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Faust PL, Kaye EM, Powers JM. Myelin lesions associated with lysosomal and peroxisomal disorders. Expert Rev Neurother 2010; 10:1449-66. [PMID: 20819015 DOI: 10.1586/ern.10.127] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Abnormalities of myelin are common in lysosomal and peroxisomal disorders. Most display a primary loss of myelin in which the myelin sheath and/or oligodendrocytes are selectively targeted by diverse pathogenetic processes. The most severe and, hence, clinically relevant are heritable diseases predominantly of infants and children, the leukodystrophies: metachromatic, globoid cell (Krabbe disease) and adreno-leukodystrophy. Our still limited understanding of these diseases has derived from multiple sources: originally, neurological-neuropathologic-neurochemical correlative studies of the natural disease in humans or other mammals, which has been enhanced by more sophisticated and contemporary techniques of cell and molecular biology. Transgenic mouse models seem to be the most promising methodology, allowing the examination of the cellular role of lysosomes and peroxisomes for formation and maintenance of both myelin and axons, and providing initial platforms to evaluate therapies. Treatment options are woefully inadequate and in their nascent stages, but still inspire some hope for the future.
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Affiliation(s)
- Phyllis L Faust
- Department of Pathology and Cell Biology, Columbia University, 630 West 168th Street, New York, NY 10032, USA.
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Chrast R, Saher G, Nave KA, Verheijen MHG. Lipid metabolism in myelinating glial cells: lessons from human inherited disorders and mouse models. J Lipid Res 2010; 52:419-34. [PMID: 21062955 DOI: 10.1194/jlr.r009761] [Citation(s) in RCA: 203] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The integrity of central and peripheral nervous system myelin is affected in numerous lipid metabolism disorders. This vulnerability was so far mostly attributed to the extraordinarily high level of lipid synthesis that is required for the formation of myelin, and to the relative autonomy in lipid synthesis of myelinating glial cells because of blood barriers shielding the nervous system from circulating lipids. Recent insights from analysis of inherited lipid disorders, especially those with prevailing lipid depletion and from mouse models with glia-specific disruption of lipid metabolism, shed new light on this issue. The particular lipid composition of myelin, the transport of lipid-associated myelin proteins, and the necessity for timely assembly of the myelin sheath all contribute to the observed vulnerability of myelin to perturbed lipid metabolism. Furthermore, the uptake of external lipids may also play a role in the formation of myelin membranes. In addition to an improved understanding of basic myelin biology, these data provide a foundation for future therapeutic interventions aiming at preserving glial cell integrity in metabolic disorders.
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Affiliation(s)
- Roman Chrast
- Department of Medical Genetics, University of Lausanne, Switzerland.
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Abstract
PURPOSE OF REVIEW Knowledge of the metabolic and genetic basis of known and previously unknown leukodystrophies is constantly increasing, opening new treatment options such as enzyme replacement or cell-based therapies. This brief review highlights some recent work, particularly emphasizing results from studies in adulthood leukodystrophies. RECENT FINDINGS Evidence from recent studies suggests increasing importance of metabolic dysfunctions, for example, in peroxisomal lipid metabolism or energy homeostasis, influencing axonal integrity and oligodendrocyte function and leading to white matter demyelination. In addition, diagnostic and therapeutic progress in metachromatic leukodystrophy, X-linked adrenoleukodystrophy, Krabbe diseases and other rare leukodystrophies with late onset are summarized. SUMMARY Better understanding of leukodystrophies in neurological routine practice is of crucial importance for differentiating between other white matter diseases such as toxic, inflammatory or vascular leukoencephalopathies. Many leukodystrophies are particularly important to recognize because specific treatments already exist or are currently under investigation. The article also provides an overview of currently known leukodystrophies in adulthood.
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Miller RH, Fyffe-Maricich SL. Restoring the balance between disease and repair in multiple sclerosis: insights from mouse models. Dis Model Mech 2010; 3:535-9. [PMID: 20647413 DOI: 10.1242/dmm.001958] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Multiple sclerosis (MS) is considered an autoimmune-mediated demyelinating disease that targets the central nervous system (CNS). Despite considerable research efforts over multiple decades, our understanding of the basic biological processes that are targeted in the disease and the mechanisms of pathogenesis are poorly understood. Consequently, current therapies directed at controlling the progression of the disease are limited in their effectiveness. Historically, the primary focus of MS research has been to define the cellular and molecular basis of the immunological pathogenic mechanisms. Recently, however, it has become clear that long-term functional recovery in MS will require the development of strategies that facilitate myelin repair in lesion areas. The emerging evidence that the adult vertebrate CNS retains the capacity to regenerate neural cells that have been lost to disease or damage has provoked intensive research focused on defining the mechanisms of myelin repair. Unfortunately, the existing animal models of MS are poorly equipped to assess myelin repair, and new validated strategies to identify therapeutics targeted at promoting myelin repair are badly needed. This Commentary will review established murine models of MS, and discuss emerging technologies that promise to provide insights into the mechanisms of myelin repair.
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Affiliation(s)
- Robert H Miller
- Department of Neurosciences, Center for Translational Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, OH 44106, USA.
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McIver SR, Muccigrosso M, Gonzales ER, Lee JM, Roberts MS, Sands MS, Goldberg MP. Oligodendrocyte degeneration and recovery after focal cerebral ischemia. Neuroscience 2010; 169:1364-75. [PMID: 20621643 DOI: 10.1016/j.neuroscience.2010.04.070] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2010] [Revised: 04/23/2010] [Accepted: 04/28/2010] [Indexed: 10/19/2022]
Abstract
The vulnerability of oligodendrocytes to ischemic injury may contribute to functional loss in diseases of central white matter. Immunocytochemical methods to identify oligodendrocyte injury in experimental models rely on epitope availability, and fail to discriminate structural changes in oligodendrocyte morphology. We previously described the use of a lentiviral vector (LV) carrying enhanced green fluorescent protein (eGFP) under the myelin basic protein (MBP) promoter for selective visualization of oligodendrocyte cell bodies and processes. In this study, we used LV-MBP-eGFP to label oligodendrocytes in rat cerebral white matter prior to transient focal cerebral ischemia, and examined oligodendrocyte injury 24 h, 48 h and 1 week post-reperfusion by quantifying cell survival and assaying the integrity of myelin processes. There was progressive loss of GFP+ oligodendrocytes in ischemic white matter at 24 and 48 h. Surviving GFP+ cells had non-pyknotic nuclear morphology and were terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL)-negative, but there was marked fragmentation of myelin processes as early as 24 h after stroke. One week after stroke, we observed a restoration of GFP+ oligodendrocytes in ischemic white matter, reflected both by cell counts and by structural integrity of myelin processes. Proliferating cells were not the main source of GFP+ oligodendrocytes, as revealed by bromodeoxyuridine (BrdU) incorporation. These observations identify novel transient structural changes in oligodendrocyte cell bodies and myelinating processes, which may have consequences for white matter function after stroke.
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Affiliation(s)
- S R McIver
- Hope Center for Neurological Disorders, Washington University School of Medicine, St Louis, MO, USA
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Abstract
In addition to their role in providing myelin for rapid impulse propagation, the glia that ensheath long axons are required for the maintenance of normal axon transport and long-term survival. This presumably ancestral function seems to be independent of myelin membrane wrapping. Here, I propose that ensheathing glia provide trophic support to axons that are metabolically isolated, and that myelin itself might cause such isolation. This glial support of axonal integrity may be relevant for a number of neurological and psychiatric diseases.
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Affiliation(s)
- Klaus-Armin Nave
- Klaus-Armin Nave is at the Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Herrmann-Rein-Strasse 3, D-37075 Goettingen, Germany.
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Shin D, Shin JY, McManus MT, Ptácek LJ, Fu YH. Dicer ablation in oligodendrocytes provokes neuronal impairment in mice. Ann Neurol 2010; 66:843-57. [PMID: 20035504 DOI: 10.1002/ana.21927] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE MicroRNAs (miRNAs) regulate gene expression and have many roles in the brain, but a role in oligodendrocyte (OL) function has not been demonstrated. METHODS A Dicer floxed conditional allele was crossed with the proteolipid protein promoter-driven inducible Cre allele to generate inducible, OL-specific Dicer-floxed mice. RESULTS OL-specific Dicer mutants show demyelination, oxidative damage, inflammatory astrocytosis and microgliosis in the brain, and eventually neuronal degeneration and shorter lifespan. miR-219 and its target ELOVL7 (elongation of very long chain fatty acids protein 7) were identified as the main molecular components that are involved in the development of the phenotype in these mice. Overexpressing ELOVL7 results in lipid accumulation, which is suppressed by miR-219 co-overexpression. In Dicer mutant brain, excess lipids accumulate in myelin-rich brain regions, and the peroxisomal beta-oxidation activity is dramatically reduced. INTERPRETATION Postnatal Dicer ablation in mature OLs results in inflammatory neuronal degeneration through increased demyelination, lipid accumulation, and peroxisomal and oxidative damage, and therefore indicates that miRNAs play an essential role in the maintenance of lipids and redox homeostasis in mature OLs that are necessary for supporting axonal integrity as well as the formation of compact myelin.
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Affiliation(s)
- Daesung Shin
- Department of Neurology, University of California San Francisco, San Francisco, CA 94158, USA
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Bradl M, Lassmann H. Oligodendrocytes: biology and pathology. Acta Neuropathol 2010; 119:37-53. [PMID: 19847447 PMCID: PMC2799635 DOI: 10.1007/s00401-009-0601-5] [Citation(s) in RCA: 557] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Revised: 10/09/2009] [Accepted: 10/10/2009] [Indexed: 11/29/2022]
Abstract
Oligodendrocytes are the myelinating cells of the central nervous system (CNS). They are the end product of a cell lineage which has to undergo a complex and precisely timed program of proliferation, migration, differentiation, and myelination to finally produce the insulating sheath of axons. Due to this complex differentiation program, and due to their unique metabolism/physiology, oligodendrocytes count among the most vulnerable cells of the CNS. In this review, we first describe the different steps eventually culminating in the formation of mature oligodendrocytes and myelin sheaths, as they were revealed by studies in rodents. We will then show differences and similarities of human oligodendrocyte development. Finally, we will lay out the different pathways leading to oligodendrocyte and myelin loss in human CNS diseases, and we will reveal the different principles leading to the restoration of myelin sheaths or to a failure to do so.
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Affiliation(s)
- Monika Bradl
- Department of Neuroimmunology, Center for Brain Research, Medical University Vienna, Vienna, Austria.
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Abstract
In multiple sclerosis, physiological repair mechanisms can help the nervous system to recover from tissue injury. Enhancing such repair mechanisms is an important, and increasingly realistic, therapeutic goal in multiple sclerosis. With respect to remyelination, several promising therapeutic avenues are currently being explored, including stem cell transplantation, LINGO-1, prolactin and glatiramer acetate. Glatiramer acetate is believed to act by the induction of specific populations of anti-inflammatory Th2 cells or Type 2 monocytes which infiltrate sites of injury in the nervous system where they release anti-inflammatory cytokines leading to bystander suppression of inflammation. In addition, these cells can release neurotrophic factors such as BDNF and IGF-1 which have been shown to stimulate the differentiation of oligodendrocyte precursor cells and thus enhance remyelination. In addition, neurotrophic factors released in response to glatiramer acetate may stimulate the differentiation of neuronal progenitor cells into mature neurones that can replace neurones lost through the disease process. This repair capacity of glatiramer acetate may contribute to the long-term well-being of patients with multiple sclerosis treated with glatiramer acetate.
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Affiliation(s)
- V Wee Yong
- Hotchkiss Brain Institute and Department of Clinical Neuroscience, University of Calgary, Calgary, Canada.
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Phylogeny of proteolipid proteins: divergence, constraints, and the evolution of novel functions in myelination and neuroprotection. ACTA ACUST UNITED AC 2009; 4:111-27. [PMID: 19497142 DOI: 10.1017/s1740925x0900009x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The protein composition of myelin in the central nervous system (CNS) has changed at the evolutionary transition from fish to tetrapods, when a lipid-associated transmembrane-tetraspan (proteolipid protein, PLP) replaced an adhesion protein of the immunoglobulin superfamily (P0) as the most abundant constituent. Here, we review major steps of proteolipid evolution. Three paralog proteolipids (PLP/DM20/DMalpha, M6B/DMgamma and the neuronal glycoprotein M6A/DMbeta) exist in vertebrates from cartilaginous fish to mammals, and one (M6/CG7540) can be traced in invertebrate bilaterians including the planktonic copepod Calanus finmarchicus that possess a functional myelin equivalent. In fish, DMalpha and DMgamma are coexpressed in oligodendrocytes but are not major myelin components. PLP emerged at the root of tetrapods by the acquisition of an enlarged cytoplasmic loop in the evolutionary older DMalpha/DM20. Transgenic experiments in mice suggest that this loop enhances the incorporation of PLP into myelin. The evolutionary recruitment of PLP as the major myelin protein provided oligodendrocytes with the competence to support long-term axonal integrity. We suggest that the molecular shift from P0 to PLP also correlates with the concentration of adhesive forces at the radial component, and that the new balance between membrane adhesion and dynamics was favorable for CNS myelination.
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Myelin proteomics: molecular anatomy of an insulating sheath. Mol Neurobiol 2009; 40:55-72. [PMID: 19452287 PMCID: PMC2758371 DOI: 10.1007/s12035-009-8071-2] [Citation(s) in RCA: 218] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2009] [Accepted: 04/14/2009] [Indexed: 12/12/2022]
Abstract
Fast-transmitting vertebrate axons are electrically insulated with multiple layers of nonconductive plasma membrane of glial cell origin, termed myelin. The myelin membrane is dominated by lipids, and its protein composition has historically been viewed to be of very low complexity. In this review, we discuss an updated reference compendium of 342 proteins associated with central nervous system myelin that represents a valuable resource for analyzing myelin biogenesis and white matter homeostasis. Cataloging the myelin proteome has been made possible by technical advances in the separation and mass spectrometric detection of proteins, also referred to as proteomics. This led to the identification of a large number of novel myelin-associated proteins, many of which represent low abundant components involved in catalytic activities, the cytoskeleton, vesicular trafficking, or cell adhesion. By mass spectrometry-based quantification, proteolipid protein and myelin basic protein constitute 17% and 8% of total myelin protein, respectively, suggesting that their abundance was previously overestimated. As the biochemical profile of myelin-associated proteins is highly reproducible, differential proteome analyses can be applied to material isolated from patients or animal models of myelin-related diseases such as multiple sclerosis and leukodystrophies.
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McTigue DM, Tripathi RB. The life, death, and replacement of oligodendrocytes in the adult CNS. J Neurochem 2008; 107:1-19. [PMID: 18643793 DOI: 10.1111/j.1471-4159.2008.05570.x] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Oligodendrocytes (OLs) are mature glial cells that myelinate axons in the brain and spinal cord. As such, they are integral to functional and efficient neuronal signaling. The embryonic lineage and postnatal development of OLs have been well-studied and many features of the process have been described, including the origin, migration, proliferation, and differentiation of precursor cells. Less clear is the extent to which OLs and damaged/dysfunctional myelin are replaced following injury to the adult CNS. OLs and their precursors are very vulnerable to conditions common to CNS injury and disease sites, such as inflammation, oxidative stress, and elevated glutamate levels leading to excitotoxicity. Thus, these cells become dysfunctional or die in multiple pathologies, including Alzheimer's disease, spinal cord injury, Parkinson's disease, ischemia, and hypoxia. However, studies of certain conditions to date have detected spontaneous OL replacement. This review will summarize current information on adult OL progenitors, mechanisms that contribute to OL death, the consequences of their loss and the pathological conditions in which spontaneous oligodendrogenesis from endogenous precursors has been observed in the adult CNS.
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Affiliation(s)
- Dana M McTigue
- Department of Neuroscience and Center for Brain and Spinal Cord Repair, The Ohio State University, Columbus, Ohio, USA.
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