title: Oxidative stress and reduced glutamine synthetase activity in the absence of inflammation in the cortex of mice with experimental allergic encephalomyelitis.
abstract: Pathological changes occur in areas of CNS tissue remote from inflammatory lesions in multiple sclerosis (MS) and its animal model experimental allergic encephalomyelitis (EAE). To determine if oxidative stress is a significant contributor to this non-inflammatory pathology, cortex tissues from mice with clinical signs of EAE were examined for evidence of inflammation and oxidative stress. Histology and gene expression analysis showed little evidence of immune/inflammatory cell invasion but reductions in natural antioxidant levels and increased protein oxidation that paralleled disease severity. Two-dimensional oxyblots and mass-spectrometry-based protein fingerprinting identified glutamine synthetase (GS) as a particular target of oxidation. Oxidation of GS was associated with reductions in enzyme activity and increased glutamate/glutamine levels. The possibility that this may cause neurodegeneration through glutamate excitotoxicity is supported by evidence of increasing cortical Ca(2+) levels in cortex extracts from animals with greater disease severity. These findings indicate that oxidative stress occurs in brain areas that are not actively undergoing inflammation in EAE and that this can lead to a neurodegenerative process due to the susceptibility of GS to oxidative inactivation.
authors.affiliation: Department of Pharmaco-Biology, Laboratory of Biochemistry and Molecular Biology, University of Bari, Via Orabona 4, 70125 Bari, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Castegna
authors.forename: L
authors.initials: L
authors.lastname: Palmieri
authors.forename: I
authors.initials: I
authors.lastname: Spera
authors.forename: V
authors.initials: V
authors.lastname: Porcelli
authors.forename: F
authors.initials: F
authors.lastname: Palmieri
authors.forename: M J
authors.initials: MJ
authors.lastname: Fabis-Pedrini
authors.forename: R B
authors.initials: RB
authors.lastname: Kean
authors.forename: D A
authors.initials: DA
authors.lastname: Barkhouse
authors.forename: M T
authors.initials: MT
authors.lastname: Curtis
authors.forename: D C
authors.initials: DC
authors.lastname: Hooper
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002540:Cerebral Cortex / Q000201:enzymology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004195:Disease Models, Animal; D015180:Electrophoresis, Gel, Two-Dimensional; D004660:Encephalitis / Q000473:pathology; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000209:etiology / Q000473:pathology* / Q000503:physiopathology*; D005260:Female; D005974:Glutamate-Ammonia Ligase / Q000032:analysis / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D019803:Glutathione Disulfide / Q000378:metabolism; D006168:Guinea Pigs; D051379:Mice; D004676:Myelin Basic Protein / Q000009:adverse effects / Q000276:immunology; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D053719:Tandem Mass Spectrometry / Q000379:methods
chemical_list: D004676:Myelin Basic Protein; D005973:Glutamine; D009243:NAD; D018698:Glutamic Acid; D009249:NADP; D052247:Nitric Oxide Synthase Type II; D005974:Glutamate-Ammonia Ligase; D005978:Glutathione; D002118:Calcium; D019803:Glutathione Disulfide