Interferon-β modulates protein synthesis in the central nervous system ☆ Susanne Beyer a , Gergana Raether a , Konstantin Stadler b , Raimund Hoffrogge c , Christian Scharf d , Arndt Rolfs e , Eilhard Mix a, 1 , Ulf Strauss a,b, ⁎ , 1 a Dept. of Neurology, University of Rostock, Gehlsheimer Str. 20,18147 Rostock, Germany b Dept. of Cell- and Neurobiology, Universitaetsmedizin Berlin Chatité, Charitéplatz 1,10115 Berlin, Germany c Dept. of Cell Culture Technique, Technical Faculty, University of Bielefeld, Postfach 10 0131, 33501 Bielefeld, Germany d Dept. of Otorhinolaryngology Head and Neck Surgery, University of Greifswald, Walther-Rathenau-Straße 43-45,17475 Greifswald, Germany e Albrecht-Kossel-Institute for Neurogeneration, University of Rostock, Gehlsheimer Str 20.,18147 Rostock, Germany, Germany abstract article info Article history: Received 16 April 2009 Received in revised form 25 May 2009 Accepted 2 June 2009 Keywords: Cycloheximide Mass spectrometry Intracellular recordings Cortical neurons Cytokines Interferon-β (IFN-β), acting canonically via the modulation of transcription, affects neocortical pyramidal neurons. By use of 2-D differential gel electrophoresis and subsequent mass spectrometry we identified IFN-β regulated proteins in the central nervous system. These proteins are involved in cytoskeleton assembly, protein transport and nucleotide metabolism and, as such, serve regenerative and protective functions. Electro- physiologically, IFN-β mediated protein synthesis is essential for part of the excitatory neuronal effects, as revealed under blockade of protein biosynthesis. This study presents novel effects of IFN-β in the central nervous system and begins to unravel the mechanism behind the known excitability changes in neurons. © 2009 Elsevier B.V. All rights reserved. 1. Introduction Inducible cytokines are key players in innate and adaptive immune responses. They are produced in response to peripheral somatic or central nervous system (CNS) inflammation (Delhaye et al., 2006) and are important in mood disorders (Dantzer et al., 2008). The mechanisms of cytokine actions within the CNS are, however, poorly understood. Interferons (IFNs) are such cytokines produced by a variety of cells primarily in response to viral infections. They exert antiviral, antiproliferative and immunomodulatory effects (Pestka, 2007; Stark et al., 1998). On the basis of their structure and receptor recognition they are classified as either type I (IFN-α and IFN-β) or type II (IFN-γ). Most type I IFN actions are mediated via IFN-β binding to the type I receptor composed of the two chains IFNAR1 and IFNAR2 by the well-described janus tyrosine kinase (Jak)/signal transducer and activator of transcription (STAT) signal pathway (David, 2002; Pestka, 2007; Stark et al., 1998; Taniguchi and Takaoka, 2001). As a result, transcriptional activator complexes translocate to the nucleus, where they bind to the IFN-stimulated response element (ISRE) and IFN-γ activated site (GAS), respectively, and initiate the transcription of a variety of target genes (Taniguchi and Takaoka, 2001). Major subsequent ISRE-dependent target genes are: IFN-stimulated gene 15 (ISG15), ISG54, IRF7, suppressor of cytokine signaling 1 (SOCS1), 2′,5′- oligoadenylate synthetase (2′,5′-OAS), protein kinase R (PKR), IFN-γ inducible protein-10 (IP-10), and β-R1 or small inducible cytokine subfamily B member 11 (SCYB11). Major GAS-dependent target genes are: IRF1, a positive feedback gene (the protein binds specifically to the virus-inducible enhancer-like elements of the IFN-β gene (Miyamoto et al., 1988), IRF-2, a negative feedback gene, IRF8, IRF-9, SOCS1, guanylate binding protein (GBP), and Fcγ receptor 1 (FcγR1). In order to identify proteins, which are involved in the IFN-β associated CNS changes, we used a proteome approach using 2-D differential gel electrophoresis (DIGE) with subsequent mass spectro- metric (MS) analysis. We tested the functional relevance of IFN-β induced protein changes on the recently discovered neuromodulatory effect (Hadji- lambreva et al., 2005). Such an approach was indicated because IFN-β regulated sets of conductance rather than by regulating a single conductance pointing to a modification of intrinsically programmed regulatory cascades by IFN-β. As a first approach we repeated our intracellular recordings in pyramidal neurons in rat brain slices pre- treated with cycloheximide and consecutively with IFN-β. Cyclohex- imide is an antibiotic produced by Streptomyces griseus. It is a well- known and potent protein synthesis inhibitor (Ennis and Lubin, 1964), which affects the translation processes in eukaryotes. The influence on Journal of Neuroimmunology 213 (2009) 31–38 ☆ This study, particularly K. S., E. M. and U.S., were supported by the Deutsche Forschungsgemeinschaft (DFG STR865/2-1). Some of the equipment used was donated by the Sonnenfeld-Stiftung, Berlin. ⁎ Corresponding author. Institute for Cell- and Neurobiology, Centre of Anatomy, Charité Universitaetsmedizin Berlin, CCM, Chariteplatz 1, 10117 Berlin, Germany. Tel.: +49 30 450 528027; fax: +49 30 450 580902. E-mail address: ulf.strauss@charite.de (U. Strauss). 1 These authors contributed equally to this work. 0165-5728/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.jneuroim.2009.06.004 Contents lists available at ScienceDirect Journal of Neuroimmunology journal homepage: www.elsevier.com/locate/jneuroim