title: Salmonella enteritidis FliC (flagella filament protein) induces human beta-defensin-2 mRNA production by Caco-2 cells.
abstract: Antimicrobial peptides are crucial for host defense at mucosal surfaces. Bacterial factors responsible for induction of human beta-defensin-2 (hBD-2) mRNA expression in Caco-2 human carcinoma cells were determined. Salmonella enteritidis, Salmonella typhimurium, Salmonella typhi, Salmonella dublin, and culture supernatants of these strains induced hBD-2 mRNA expression in Caco-2 human carcinoma cells. Using luciferase as a reporter gene for a approximately 2.1-kilobase pair hBD-2 promoter, the hBD-2-inducing factor in culture supernatant of S. enteritidis was isolated. The supernatant factor was heat-stable and proteinase-sensitive. After purification by anion exchange and gel filtration chromatography, the hBD-2-inducing factor was identified as a 53-kDa monomeric protein with the amino-terminal sequence AQVINTNSLSLLTQNNLNK, which is identical to that of the flagella filament structural protein (FliC) of S. enteritidis. Consistent with this finding, the 53-kDa protein reacted with anti-FliC antibody, which prevented its induction of hBD-2 mRNA in Caco-2 cells. In agreement, the hBD-2-inducing activity in culture supernatant was completely neutralized by anti-FliC antibody. In gel retardation analyses, FliC increased binding of NF-kappaB (p65 homodimer) to hBD-2 gene promoter sequences. We conclude that S. enteritidis FliC induces hBD-2 expression in Caco-2 cells via NF-kappaB activation and thus plays an important role in up-regulation of the innate immune response.
authors.affiliation: Department of Bacteriology, Nagasaki University, Sakamoto, Nagasaki 852-8523, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ogushi
authors.forename: A
authors.initials: A
authors.lastname: Wada
authors.forename: T
authors.initials: T
authors.lastname: Niidome
authors.forename: N
authors.initials: N
authors.lastname: Mori
authors.forename: K
authors.initials: K
authors.lastname: Oishi
authors.forename: T
authors.initials: T
authors.lastname: Nagatake
authors.forename: A
authors.initials: A
authors.lastname: Takahashi
authors.forename: H
authors.initials: H
authors.lastname: Asakura
authors.forename: S
authors.initials: S
authors.lastname: Makino
authors.forename: H
authors.initials: H
authors.lastname: Hojo
authors.forename: Y
authors.initials: Y
authors.lastname: Nakahara
authors.forename: M
authors.initials: M
authors.lastname: Ohsaki
authors.forename: T
authors.initials: T
authors.lastname: Hatakeyama
authors.forename: H
authors.initials: H
authors.lastname: Aoyagi
authors.forename: H
authors.initials: H
authors.lastname: Kurazono
authors.forename: J
authors.initials: J
authors.lastname: Moss
authors.forename: T
authors.initials: T
authors.lastname: Hirayama
mesh_terms: D000595:Amino Acid Sequence; D015153:Blotting, Western; D018938:Caco-2 Cells; D002467:Cell Nucleus / Q000378:metabolism; D002850:Chromatography, Gel; D002852:Chromatography, Ion Exchange; D019281:Dimerization; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation; D004926:Escherichia coli / Q000378:metabolism; D005408:Flagellin / Q000378:metabolism*; D017353:Gene Deletion; D006801:Humans; D007239:Infections / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D012333:RNA, Messenger / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012475:Salmonella / Q000737:chemistry; D012477:Salmonella enteritidis / Q000737:chemistry*; D014162:Transfection; D015854:Up-Regulation; D023083:beta-Defensins / Q000096:biosynthesis*
chemical_list: C106641:DEFB4A protein, human; D016328:NF-kappa B; D012333:RNA, Messenger; D011994:Recombinant Proteins; D023083:beta-Defensins; D005408:Flagellin; D008156:Luciferases