title: Demyelination induced by oxidative stress is regulated by sphingosine 1-phosphate receptors.
abstract: Oxidative stress is a pathological condition defined as an imbalance between production and removal of reactive oxygen species. This process causes structural cell damage, disrupts DNA repair and induces mitochondrial dysfunction. Many in vitro studies have used direct bolus application of H2O2to investigate the role of oxidative stress in cell culture. In this study, using mouse organotypic cerebellar slice cultures, the effects of H2O2-induced oxidative stress on myelination state were examined, using bolus concentrations of H2O2(0.1-1 mM) and low-continuous H2O2(∼20 μM) generated from glucose oxidase and catalase (GOX-CAT). Using these models, the potential therapeutic effects of pFTY720, an oral therapy used in multiple sclerosis, was also examined. We found bolus treatment of H2O2(0.5 mM) and, for the first time, low-continuous H2O2(GOX-CAT) to induce demyelination in organotypic slices. Both bolus H2O2and GOX-CAT treatments significantly decreased vimentin expression in these slice cultures as well as increased cell death in isolated astrocyte cultures. Importantly, pre-treatment with pFTY720 significantly attenuated both bolus H2O2and GOX-CAT-induced demyelination and the GOX-CAT-induced decrease in vimentin in cerebellar slices, without altering levels of the proinflammatory cytokines such as IL-6 and CX3CL1. We also observed increased SMI-32 immunoreactivity in the white matter tract induced by GOX-CAT indicating axonal damage, which was remarkably attenuated by pFTY720. Taken together, this data establishes a novel GOX-CAT model of demyelination and demonstrates that pFTY720 can act independently of inflammatory cytokines to attenuate decreases in vimentin, as well as axonal damage and demyelination induced by oxidative stress.
authors.affiliation: Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland.
authors.forename: Sinead A
authors.initials: SA
authors.lastname: O'Sullivan
authors.affiliation: Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland.
authors.forename: Maria
authors.initials: M
authors.lastname: Velasco-Estevez
authors.affiliation: Drug Development, School of Medicine, Trinity College Dublin, Dublin, Ireland.
authors.forename: Kumlesh K
authors.identifier: 0000-0003-4274-9119
authors.initials: KK
authors.lastname: Dev
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D001253:Astrocytes / Q000187:drug effects / Q000502:physiology; D001921:Brain / Q000166:cytology; D002135:Calcium-Binding Proteins; D002478:Cells, Cultured; D002531:Cerebellum / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000378:metabolism; D003711:Demyelinating Diseases / Q000188:drug therapy / Q000209:etiology* / Q000378:metabolism*; D005260:Female; D005333:Fetus; D000068876:Fingolimod Hydrochloride / Q000627:therapeutic use; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D006861:Hydrogen Peroxide / Q000633:toxicity; D007166:Immunosuppressive Agents / Q000627:therapeutic use; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008840:Microfilament Proteins; D063308:Myelin-Oligodendrocyte Glycoprotein / Q000378:metabolism; D016900:Neurofilament Proteins / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D049349:Receptors, Lysosphingolipid / Q000235:genetics / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism; D029961:Zebrafish Proteins / Q000378:metabolism
chemical_list: C112986:AIF1 protein, human; D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D007166:Immunosuppressive Agents; C576395:MYEF2 protein, zebrafish; D008840:Microfilament Proteins; D063308:Myelin-Oligodendrocyte Glycoprotein; D016900:Neurofilament Proteins; D049349:Receptors, Lysosphingolipid; D012097:Repressor Proteins; D029961:Zebrafish Proteins; C051774:neurofilament protein H; D006861:Hydrogen Peroxide; D000068876:Fingolimod Hydrochloride
keywords: catalase; cerebellar slices; glucose oxidase; low continuous H2O2, pFTY720