Site-Specific Production of IL-6 in the Central Nervous System Retargets and Enhances the Inflammatory Response in Experimental Autoimmune This information is current as Encephalomyelitis of September 26, 2021. Albert Quintana, Marcus Müller, Ricardo F. Frausto, Raquel Ramos, Daniel R. Getts, Elisenda Sanz, Markus J. Hofer, Marius Krauthausen, Nicholas J. C. King, Juan Hidalgo and Iain L. Campbell Downloaded from J Immunol 2009; 183:2079-2088; Prepublished online 13 July 2009; doi: 10.4049/jimmunol.0900242 http://www.jimmunol.org/content/183/3/2079 http://www.jimmunol.org/ Supplementary http://www.jimmunol.org/content/suppl/2009/07/14/jimmunol.090024 Material 2.DC1 References This article cites 50 articles, 15 of which you can access for free at: http://www.jimmunol.org/content/183/3/2079.full#ref-list-1 by guest on September 26, 2021 Why The JI? Submit online. • Rapid Reviews! 30 days* from submission to initial decision • No Triage! Every submission reviewed by practicing scientists • Fast Publication! 4 weeks from acceptance to publication *average Subscription Information about subscribing to The Journal of Immunology is online at: http://jimmunol.org/subscription Permissions Submit copyright permission requests at: http://www.aai.org/About/Publications/JI/copyright.html Email Alerts Receive free email-alerts when new articles cite this article. Sign up at: http://jimmunol.org/alerts The Journal of Immunology is published twice each month by The American Association of Immunologists, Inc., 1451 Rockville Pike, Suite 650, Rockville, MD 20852 Copyright © 2009 by The American Association of Immunologists, Inc. All rights reserved. Print ISSN: 0022-1767 Online ISSN: 1550-6606. The Journal of Immunology Site-Specific Production of IL-6 in the Central Nervous System Retargets and Enhances the Inflammatory Response in Experimental Autoimmune Encephalomyelitis1 Albert Quintana,2,3*§ Marcus Mu¨ller,2,4* Ricardo F. Frausto,* Raquel Ramos,§ Daniel R. Getts,5† Elisenda Sanz,3*§ Markus J. Hofer,6* Marius Krauthausen,4* Nicholas J. C. King,†‡ Juan Hidalgo,§ and Iain L. Campbell7*‡ IL-6 is crucial for the induction of many murine models of autoimmunity including experimental autoimmune encephalomyelitis (EAE), an animal model for multiple sclerosis. To establish the role of site-specific production of IL-6 in autoimmunity, we examined myelin oligodendrocyte glycoprotein immunization-induced EAE in transgenic mice (GFAP-IL6) with IL-6 production restricted to the cerebellum. Myelin oligodendrocyte glycoprotein-immunized (Mi-) GFAP-IL6 mice developed severe ataxia but Downloaded from no physical signs of spinal cord involvement, which was in sharp contrast to Mi-wild type (WT) animals that developed classical EAE with ascending paralysis. Immune pathology and demyelination were nearly absent from the spinal cord, but significantly increased in the cerebellum of Mi-GFAP-IL6 mice. Tissue damage in the cerebellum in the Mi-GFAP-IL6 mice was accompanied by increased total numbers of infiltrating leukocytes and increased proportions of both neutrophils and B-cells. With the exception of IL-17 mRNA, which was elevated in both control immunized and Mi-GFAP-IL6 cerebellum, the level of other cytokine and chemokine mRNAs were comparable with Mi-WT cerebellum whereas significantly higher levels of IFN-␥ and TNF-␣ mRNA http://www.jimmunol.org/ were found in Mi-WT spinal cord. Thus, site-specific production of IL-6 in the cerebellum redirects trafficking away from the normally preferred antigenic site the spinal cord and acts as a leukocyte “sink” that markedly enhances the inflammatory cell accumulation and disease. The mechanisms underlying this process likely include the induction of specific chemokines, activation of microglia, and activation and loss of integrity of the blood-brain barrier present in the cerebellum of the GFAP-IL6 mice before the induction of EAE. The Journal of Immunology, 2009, 183: 2079–2088. nterleukin-6 is a plurifunctional cytokine that is implicated in is crucial for the induction of immune pathology and clinical disease the pathogenesis of numerous autoimmune disorders in humans, in collagen-induced (3) or spontaneous (4) arthritis and in experimen- by guest on September 26, 2021 I including rheumatoid arthritis (1) and multiple sclerosis (MS)8 tal autoimmune encephalomyelitis (EAE; Ref. 5, 6), which are murine (2). Experimental studies in IL-6 knockout (KO) mice show that IL-6 models for the human autoimmune disorders rheumatoid arthritis and MS, respectively. Recent studies have identified a subpopulation of CD4ϩ Th cells, namely Th17 T-cells, that are key Ag-specific effector *School of Molecular and Microbial Biosciences, †Department of Pathology and ‡ § T cells in these murine models (4, 7–9). The demonstration that the Bosch Institute, University of Sydney, Australia; and Institute of Neurosciences and ␤ Department of Cellular Biology, Physiology and Immunology, Autonomous Univer- formation of Th17 T cells is driven by IL-6 together with TGF- in sity Barcelona, Spain vitro and in vivo (7, 10–12) explains, in part, why the murine auto- Received for publication January 22, 2009. Accepted for publication June 1, 2009. immune models are critically dependent on IL-6. However, in the case The costs of publication of this article were defrayed in part by the payment of page of EAE, studies to pin down the precise role of IL-6 in the induction charges. This article must therefore be hereby marked advertisement in accordance of EAE have failed to identify a unifying mechanism. One study with 18 U.S.C. Section 1734 solely to indicate this fact. suggested that IL-6 is necessary for the induction of cerebrovascular 1 This work was supported by a New South Wales Spinal Cord Injury and Other Neu- adhesion molecules such as VCAM-1, which are crucial for leuko- rological Conditions Project Grant and a start up grant from the University of Sydney (to I.L.C.); and by SAF2008–00435, FP6 Integrated Project Exgenesis (LSHM-CT-2004– cyte trafficking to the CNS in EAE (13); a second study con- 005272), and RETICS (REEM, RD07/0060/0002) to J.H. D.G. was supported by an cluded that local, perivascular-produced IL-6 is needed for the Australian Postgraduate Award. M.J.H. and M.M. were postdoctoral fellows of the Deut- sche Forschungsgemeinschaft HO3298/1–1 and Mu17–07/3–1, respectively. M.M. was induction of EAE and not peripheral IL-6 (5), while a third also supported by the fund “Innovative Medical Research” of the University of Mu¨nster study proposed that IL-6 is required for autoantigen-reactive Medical School, Germany. A.Q. and E.S. were predoctoral fellows of the Ministerio de CD4ϩ-T cell proliferation during EAE (6). Finally, in a more Educacio´n y Ciencia, BES-2003–2427 and AP2003–0534, respectively. R.F. was sup- ported by a University of Sydney International Research Scholarship. R.R. was a pre- recent report IL-6 was shown to be a dominant inhibitor of the doctoral fellow of Generalitat de Catalunya 2006FI-01355. conversion of conventional T cells to FoxP3-positive T regulatory 2 A.Q. and M.M. contributed equally to this work. (reg) cells with the loss of IL-6 resulting in an overwhelming T reg 3 Current address: Department of Biochemistry (A.Q.) and Department of Pharma- cology (E.S.), University of Washington, Seattle, WA. 4 Current address: Department of Neurology, University of Bonn, Germany. 5 Current address: Department of Microbiology-Immunology, Northwestern Univer- 8 Abbreviations used in this paper: MS, multiple sclerosis; KO, knockout; EAE, sity, Chicago, IL. experimental autoimmune encephalomyelitis; T reg, regulatory T cell; MOG, my- 6 elin oligodendrocyte glycoprotein; BBB, blood-brain barrier; WT, wild type; Current address: Department of Neuropathology, University of Marburg, Germany. LFB, luxol fast blue; RPA, RNase protection assay; Ni, nonimmunized; Ci, BSA- 7 Address correspondence and reprint requests to Dr. Iain L. Campbell, School of CFA-immunized; Mi, MOG-CFA-immunized. Molecular and Microbial Biosciences G08, University of Sydney, New South Wales, 2006, Australia. E-mail address: [email protected] Copyright © 2009 by The American Association of Immunologists, Inc. 0022-1767/09/$2.00 www.jimmunol.org/cgi/doi/10.4049/jimmunol.0900242 2080 SITE-SPECIFIC PRODUCTION OF IL-6 TARGETS AUTOIMMUNITY response that prevents the induction of Th1 and Th17 effector cells (3 mg/ml) and 100 ␮l CFA (Sigma-Aldrich) supplemented with 4 mg/ml in EAE (14). Mycobacterium tuberculosis H37RA (Difco). In addition, animals received During an autoimmune response, the production of IL-6 is an i.p. injection of 500 ng pertussis toxin (Sigma-Aldrich), which was repeated 2 days after immunization. As controls, another cohort of mice known to arise from a large number of different cell types that from each genotype (n ϭ 4) was immunized similarly with the exception include infiltrating leukocytes as well as tissue-resident cells (15). that MOG peptide was replaced with BSA. Adoptive transfer experiments in a spontaneous arthritis model (4) Immunized animals were examined daily and scored for EAE. Initially, as well as in EAE (5) suggest that the local cytokine milieu may we observed that GFAP-IL6 mice showed reduced classical clinical signs (which typically reflect spinal cord involvement), while displaying non- also play an important role in modulating the development and classical clinical signs of ataxia. To better characterize the clinical evolu- progression of disease. Due to the plurifunctional nature of IL-6, it tion of the disease in the two genotypes used, an elaborated general clinical is likely that in addition to its potential to control the activity of score that included the prototypical physical signs of EAE and an addi- infiltrating self-reactive Th17 T cells, that this cytokine may in- tional score for ataxia was used. The general clinical score was assessed for ϭ fluence the pathogenesis of autoimmunity at multiple levels, e.g., each animal according to the following criteria: 0 no signs of disease, 1 ϭ loss of tail tonus, 1.5 ϭ moderate hind limb paraparesis, 2 ϭ severe via the regulation of adhesion molecule expression on vascular hind limb paraparesis, 3 ϭ hind limb paralysis, 4 ϭ tetraplegia, and 5 ϭ endothelium (16).