title: Astrocyte-targeted production of interleukin-6 reduces astroglial and microglial activation in the cuprizone demyelination model: Implications for myelin clearance and oligodendrocyte maturation.
abstract: Multiple sclerosis (MS) is a chronic demyelinating disease of the central nervous system. Interleukin (IL)-6 is a pleiotropic cytokine with a potential role in MS. Here we used transgenic mice with astrocyte-targeted production of IL-6 (GFAP-IL6Tg) to study the effect of IL-6 in the cuprizone-induced demyelination paradigm, which is an experimental model of de- and re-myelination, both hallmarks of MS. Our results demonstrated that cuprizone-treated GFAP-IL6Tg mice showed a significant reduction in astroglial and especially microglial activation/accumulation in the corpus callosum in comparison with the corresponding cuprizone-treated wild type (WT). Production of a key microglial attracting chemokine CXCL10, as well as CXCL1 and CCL4 was lower in cuprizone-treated GFAP-IL6Tg mice compared with cuprizone-treated WT. Reduced microglial cell accumulation was associated with inefficient removal of degraded myelin and axonal protection in cuprizone-treated GFAP-IL6Tg mice, compared with WT mice at the peak of demyelination. In addition, transgenic production of IL-6 did not alter initial oligodendrocyte (OL) apoptosis and oligodendrocyte precursor cell recruitment to the lesion site, but it impaired early OL differentiation, possibly due to impaired removal of degraded myelin. Indeed, a microglial receptor involved in myelin phagocytosis, TREM2, as well as the phagolysosomal protein CD68 were lower in cuprizone-treated GFAP-IL6Tg compared with WT mice. Our results show for the first time that astrocyte-targeted production of IL-6 may play a role in modulating experimental demyelination induced by cuprizone. Further understanding of the IL-6-mediated molecular mechanisms involved in the regulation of demyelination is needed, and may have implications for the development of future therapeutic strategies for the treatment of MS. GLIA 2016;64:2104-2119.
authors.affiliation: Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Bellaterra, 08193, Spain. petkovicfilip@yahoo.com.|Department of Immunology, Institute for Biological Research ″Sinisa Stankovic, 11000, Belgrade, Serbia. petkovicfilip@yahoo.com.
authors.forename: Filip
authors.initials: F
authors.lastname: Petković
authors.affiliation: School of Molecular Bioscience, University of Sydney, Sydney, NSW, 2006, Australia.
authors.forename: Iain L
authors.initials: IL
authors.lastname: Campbell
authors.affiliation: Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Bellaterra, 08193, Spain.
authors.forename: Berta
authors.initials: B
authors.lastname: Gonzalez
authors.affiliation: Department of Cell Biology, Physiology and Immunology, Institute of Neuroscience, Universitat Autònoma De Barcelona, Bellaterra, 08193, Spain.
authors.forename: Bernardo
authors.initials: B
authors.lastname: Castellano
mesh_terms: D016564:Amyloid beta-Protein Precursor / Q000378:metabolism; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D003471:Cuprizone / Q000633:toxicity; D016207:Cytokines / Q000378:metabolism; D003711:Demyelinating Diseases / Q000139:chemically induced*; D004195:Disease Models, Animal; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D008840:Microfilament Proteins / Q000378:metabolism; D017628:Microglia / Q000187:drug effects / Q000378:metabolism*; D008996:Monoamine Oxidase Inhibitors / Q000633:toxicity; D004676:Myelin Basic Protein / Q000378:metabolism; D009186:Myelin Sheath / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism*
chemical_list: C491049:Aif1 protein, mouse; D016564:Amyloid beta-Protein Precursor; D002135:Calcium-Binding Proteins; D016207:Cytokines; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D008840:Microfilament Proteins; D008996:Monoamine Oxidase Inhibitors; D004676:Myelin Basic Protein; D009419:Nerve Tissue Proteins; D011971:Receptors, Immunologic; C498716:Trem2 protein, mouse; D049452:Green Fluorescent Proteins; D003471:Cuprizone; D053148:Caspase 3
keywords: CXCL10; chemokines; multiple sclerosis; neuroinflammation; oligodendrocytes