title: Enterohaemorrhagic Escherichia coli serogroup O111 inhibits NF-(kappa)B-dependent innate responses in a manner independent of a type III secreted OspG orthologue.
abstract: Enterohaemorrhagic and enteropathogenic Escherichia coli (EHEC and EPEC) inject a repertoire of effector proteins into host cells via a type III secretion system (T3SS) encoded by the locus of enterocyte effacement (LEE). OspG is an effector protein initially identified in Shigella that was shown to inhibit the host innate immune response. In this study, we found ospG homologues in EHEC (mainly of serogroup O111) and in Yersinia enterocolitica. The T3SS encoded by the LEE was able to inject these different OspG homologues into host cells. Infection of HeLa cells with EHEC O111 inhibited the NF-kappaB-dependent innate immune response via a T3SS-dependent mechanism. However, an EHEC O111 ospG mutant was still able to inhibit NF-kappaB p65 transfer to the nucleus in infected cells stimulated by tumour necrosis factor alpha (TNF-alpha). In addition, no difference in the inflammatory response was observed between wild-type EHEC O111 and the isogenic ospG mutant in the rabbit ligated intestinal loop model. These results suggest that OspG is not the sole effector protein involved in the inactivation of the host innate immune system during EHEC O111 infection.
authors.affiliation: Université de Toulouse, ENVT, UMR1225, F-31076 Toulouse, France.|INRA, UMR1225, ENVT, F-31076 Toulouse, France.
authors.forename: Rika
authors.initials: R
authors.lastname: Nobe
authors.affiliation: Université de Toulouse, ENVT, UMR1225, F-31076 Toulouse, France.|INRA, UMR1225, ENVT, F-31076 Toulouse, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Nougayrède
authors.affiliation: Université de Toulouse, ENVT, UMR1225, F-31076 Toulouse, France.|INRA, UMR1225, ENVT, F-31076 Toulouse, France.
authors.forename: Frédéric
authors.initials: F
authors.lastname: Taieb
authors.affiliation: Department of Infectious Diseases, Bacteriology, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, Liège B4000, Belgium.
authors.forename: Marjorie
authors.initials: M
authors.lastname: Bardiau
authors.affiliation: Department of Morphology and Pathology, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, Liège B4000, Belgium.
authors.forename: Dominique
authors.initials: D
authors.lastname: Cassart
authors.affiliation: Department of Cell Biology, Centro de Investigación y de Estudios Avanzados (CINVESTAV-IPN), Ap. Postal 14-740, 07000 Mexico DF, Mexico.
authors.forename: Fernando
authors.initials: F
authors.lastname: Navarro-Garcia
authors.affiliation: Department of Infectious Diseases, Bacteriology, Faculty of Veterinary Medicine, University of Liège, Sart Tilman, Liège B4000, Belgium.
authors.forename: Jacques
authors.initials: J
authors.lastname: Mainil
authors.affiliation: Division of Bioenvironmental Science, Frontier Science Research Center, University of Miyazaki, 5200 Kiyotake, Miyazaki 889-1692, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Hayashi
authors.affiliation: Université de Toulouse, ENVT, UMR1225, F-31076 Toulouse, France.|INRA, UMR1225, ENVT, F-31076 Toulouse, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Oswald
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D054324:Enterohemorrhagic Escherichia coli / Q000276:immunology* / Q000472:pathogenicity*; D054308:Enteropathogenic Escherichia coli / Q000276:immunology / Q000472:pathogenicity; D004927:Escherichia coli Infections / Q000276:immunology* / Q000382:microbiology* / Q000473:pathology; D029968:Escherichia coli Proteins / Q000502:physiology*; D023061:Gene Order; D006367:HeLa Cells; D006801:Humans; D007113:Immunity, Innate; D007422:Intestines / Q000382:microbiology / Q000473:pathology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D011817:Rabbits; D016415:Sequence Alignment; D012703:Serotyping; D037521:Virulence Factors / Q000502:physiology*
chemical_list: D029968:Escherichia coli Proteins; D016328:NF-kappa B; C545437:OspG protein, E coli; D037521:Virulence Factors