title: Rothia dentocariosa induces TNF-alpha production in a TLR2-dependent manner.
abstract: Previous work suggested that Rothia dentocariosa is associated with periodontal inflammatory disease. However, little is known about the pathogenicity of this bacterium. To characterize host response to this bacterium, we measured (via ELISA) the amount of TNF-α in the culture supernatant following the stimulation of THP-1 cells (a human acute monocytic leukemia cell line) with R. dentocariosa cells (ATCC14189 and ATCC14190). Exposure to bacterial cells induced the production of TNF-α in a dose-dependent manner. The bacterial induction of TNF-α in THP-1 cells was mediated by the Toll-like receptor 2 (TLR2), as demonstrated by gene-specific knockdown via siRNA, which successfully suppressed TLR2 expression and significantly inhibited the production of TNF-α in the culture supernatant. To confirm the role of TLR2, we examined TLR2-dependent NF-κB activation by R. dentocariosa cells in a distinct cell line. Specifically, HEK293 cells were transiently cotransfected with the human TLR2 gene and an NF-κB-dependent luciferase-encoding reporter gene. The bacterial cells induced NF-κB activation in the transfected HEK293 cells in a dose-dependent manner. In contrast, bacterial cells failed to induce NF-κB activation in cells transfected with pEF6 control vector. Taken together, these results suggest that R. dentocariosa induces host TNF-α production by a TLR2-dependent mechanism.
authors.affiliation: Departments of Oral Microbiology and Immunology, Showa University School of Dentistry, Tokyo, Japan.
authors.forename: Hideo
authors.initials: H
authors.lastname: Kataoka
authors.forename: Makoto
authors.initials: M
authors.lastname: Taniguchi
authors.forename: Haruka
authors.initials: H
authors.lastname: Fukamachi
authors.forename: Takafumi
authors.initials: T
authors.lastname: Arimoto
authors.forename: Hirobumi
authors.initials: H
authors.lastname: Morisaki
authors.forename: Hirotaka
authors.initials: H
authors.lastname: Kuwata
mesh_terms: D002460:Cell Line; D004797:Enzyme-Linked Immunosorbent Assay; D055785:Gene Knockdown Techniques; D006801:Humans; D008835:Micrococcaceae / Q000276:immunology*; D009000:Monocytes / Q000276:immunology / Q000382:microbiology; D051195:Toll-Like Receptor 2 / Q000276:immunology / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis* / Q000276:immunology
chemical_list: C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D014409:Tumor Necrosis Factor-alpha
keywords: Rothia dentocariosa; TNF-α; Toll-like receptor 2; inflammation