title: Gene-Expression Profiling Suggests Impaired Signaling via the Interferon Pathway in Cstb-/- Microglia.
abstract: Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1, OMIM254800) is an autosomal recessive neurodegenerative disorder characterized by stimulus-sensitive and action-activated myoclonus, tonic-clonic epileptic seizures, and ataxia. Loss-of-function mutations in the gene encoding the cysteine protease inhibitor cystatin B (CSTB) underlie EPM1. The deficiency of CSTB in mice (Cstb-/- mice) generates a phenotype resembling the symptoms of EPM1 patients and is accompanied by microglial activation at two weeks of age and an upregulation of immune system-associated genes in the cerebellum at one month of age. To shed light on molecular pathways and processes linked to CSTB deficiency in microglia we characterized the transcriptome of cultured Cstb-/- mouse microglia using microarray hybridization and RNA sequencing (RNA-seq). The gene expression profiles obtained with these two techniques were in good accordance and not polarized to either pro- or anti-inflammatory status. In Cstb-/- microglia, altogether 184 genes were differentially expressed. Of these, 33 genes were identified by both methods. Several interferon-regulated genes were weaker expressed in Cstb-/- microglia compared to control. This was confirmed by quantitative real-time PCR of the transcripts Irf7 and Stat1. Subsequently, we explored the biological context of CSTB deficiency in microglia more deeply by functional enrichment and canonical pathway analysis. This uncovered a potential role for CSTB in chemotaxis, antigen-presentation, and in immune- and defense response-associated processes by altering JAK-STAT pathway signaling. These data support and expand the previously suggested involvement of inflammatory processes to the disease pathogenesis of EPM1 and connect CSTB deficiency in microglia to altered expression of interferon-regulated genes.
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Inken
authors.initials: I
authors.lastname: Körber
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Katayama
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Elisabet
authors.initials: E
authors.lastname: Einarsdottir
authors.affiliation: Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.|Competence Centre on Health Technologies, Tartu, Estonia.
authors.forename: Kaarel
authors.initials: K
authors.lastname: Krjutškov
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Paula
authors.initials: P
authors.lastname: Hakala
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Department of Biosciences and Nutrition, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Juha
authors.initials: J
authors.lastname: Kere
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Anna-Elina
authors.initials: AE
authors.lastname: Lehesjoki
authors.affiliation: Folkhälsan Institute of Genetics, Helsinki, Finland.|Research Program's Unit, Molecular Neurology, University of Helsinki, Helsinki, Finland.|Neuroscience Center, University of Helsinki, Helsinki, Finland.
authors.forename: Tarja
authors.initials: T
authors.lastname: Joensuu
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000737:chemistry; D055313:Cystatin B / Q000235:genetics*; D020869:Gene Expression Profiling; D007372:Interferons / Q000378:metabolism*; D053613:Janus Kinase 1 / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D017628:Microglia / Q000378:metabolism; D009154:Mutation; D010641:Phenotype; D050794:STAT1 Transcription Factor / Q000378:metabolism; D017423:Sequence Analysis, RNA; D015398:Signal Transduction; D020194:Unverricht-Lundborg Syndrome / Q000235:genetics* / Q000473:pathology
chemical_list: D000893:Anti-Inflammatory Agents; C524992:Cstb protein, mouse; D050794:STAT1 Transcription Factor; C494080:Stat1 protein, mouse; D055313:Cystatin B; D007372:Interferons; C507905:Jak1 protein, mouse; D053613:Janus Kinase 1