title: Microarray analysis of macrophage response to infection with Streptococcus oralis reveals the immunosuppressive effect of hydrogen peroxide.
abstract: Oral streptococci including mitis group streptococci are commensal residents and are also the first to colonize the oral cavity. However, various species of these oral streptococci have the potential to invade the host and occasionally lead to severe infectious disease such as cardiovascular diseases. Oral streptococci have close interactions with the host immune system including macrophages at the oral mucosal surface. One notable common trait of oral streptococcus including Streptococcus oralis (S. oralis) is the production of hydrogen peroxide (H2O2). Using a comprehensive microarray approach, we sought to understand the innate immune response profiling affected by H2O2production from oral streptococci. We compared the gene expression patterns of macrophages infected with S. oralis wild type (WT) and streptococcal pyruvate oxidase knockout (SpxB-KO), a strain that does not produce H2O2. We found that H2O2from S. oralis suppressed proinflammatory gene expression such as TNF-α, that is induced in response to infection, and activated the cellular stress genes such as Egr-1 in response to oxidative stress. A comparative gene ontology analysis of S. oralis WT and SpxB-KO strains revealed that during infection, down regulated genes were closely related to the processes involved in the host defense reaction and up regulated genes were related with the cellular stress responses. Using qPCR analysis, we also confirmed the same pattern of expression changes such as TNF-α, IL-6 and Egr-1. Furthermore, supernatant from SpxB-KO could not suppress the expression of TNF-α in macrophages stimulated with LPS. These findings suggested that H2O2production from S. oralis leads to the suppression of inflammatory responses and NF-κB signaling pathways in macrophages as well as the induction of the oxidative stress response. We concluded that streptococcal H2O2production has the beneficial effects of modulating the innate immune response, thereby stabilizing streptococcal colonization at the mucosal surface and even in the bloodstream leading to cardiovascular disease after invasion, in addition to the commensal role to compete other bacterial species as initial colonizer at oral cavity.
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan; Department of Pediatric Dentistry, School of Dentistry, Showa University, 2-1-1 Kitasenzoku, Ohta-ku, Tokyo 145-8515, Japan.
authors.forename: Hitomi
authors.initials: H
authors.lastname: Matsushima
authors.affiliation: Quantitative Immunology Research Unit, Immunology Frontier Research Center, Osaka University, Yamadaoka 3-1, Suita, Osaka 565-0871, Japan.
authors.forename: Yutaro
authors.initials: Y
authors.lastname: Kumagai
authors.affiliation: Immuno-Genomics Research Unit, Immunology Frontier Research Center, Osaka University, Yamadaoka 3-1, Suita, Osaka 565-0871, Japan.
authors.forename: Alexis
authors.initials: A
authors.lastname: Vandenbon
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kataoka
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan; Department of Special Needs Dentistry, Division of Dentistry for Persons with Disabilities, School of Dentistry, Showa University, Kitasenzoku 2-1-1, Ohta-ku, Tokyo 145-8515, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Kadena
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Haruka
authors.initials: H
authors.lastname: Fukamachi
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Arimoto
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan.
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Morisaki
authors.affiliation: Department of Food and Nutrition, Faculty of Contemporary Human Life Science, Tezukayama University, Tezukayama 7-1-1, Nara City, Nara 631-8585, Japan.
authors.forename: Nagatoshi
authors.initials: N
authors.lastname: Fujiwara
authors.affiliation: Center for Frontier Oral Science, Osaka University Graduate School of Dentistry, Yamadaoka 1-8, Suita, Osaka 565-0871, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Okahashi
authors.affiliation: Department of Oral Microbiology and Immunology, School of Dentistry, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan. Electronic address: hkuwata@dent.showa-u.ac.jp.
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Kuwata
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D015153:Blotting, Western; D002460:Cell Line; D016000:Cluster Analysis; D051766:Early Growth Response Protein 1 / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling / Q000379:methods*; D063990:Gene Ontology; D054884:Host-Pathogen Interactions; D006861:Hydrogen Peroxide / Q000378:metabolism*; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism* / Q000382:microbiology; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods*; D011771:Pyruvate Oxidase / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019533:Streptococcus oralis / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D051766:Early Growth Response Protein 1; C486109:Egr1 protein, mouse; D015850:Interleukin-6; D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D006861:Hydrogen Peroxide; D011771:Pyruvate Oxidase
keywords: Hydrogen peroxide; Immune responses; Macrophage; Microarray analysis; Streptococcus oralis