title: Use of OmpU porins for attachment and invasion of Crassostrea gigas immune cells by the oyster pathogen Vibrio splendidus.
abstract: OmpU porins are increasingly recognized as key determinants of pathogenic host Vibrio interactions. Although mechanisms remain incompletely understood, various species, including the human pathogen Vibrio cholera, require OmpU for host colonization and virulence. We have shown previously that OmpU is essential for virulence in the oyster pathogen Vibrio splendidus LGP32. Here, we showed that V. splendidus LGP32 invades the oyster immune cells, the hemocytes, through subversion of host-cell actin cytoskeleton. In this process, OmpU serves as an adhesin/invasin required for β-integrin recognition and host cell invasion. Furthermore, the major protein of oyster plasma, the extracellular superoxide dismutase Cg-EcSOD, is used as an opsonin mediating the OmpU-promoted phagocytosis through its RGD sequence. Finally, the endocytosed bacteria were found to survive intracellularly, evading the host defense by preventing acidic vacuole formation and limiting reactive oxygen species production. We conclude that (i) V. splendidus is a facultative intracellular pathogen that manipulates host defense mechanisms to enter and survive in host immune cells, and (ii) that OmpU is a major determinant of host cell invasion in Vibrio species, used by V. splendidus LGP32 to attach and invade oyster hemocytes through opsonisation by the oyster plasma Cg-EcSOD.
authors.affiliation: Institut Français de Recherche pour l'Exploitation de la Mer, Centre National de la Recherche Scientifique, Université Montpellier 2, 34095 Montpellier, France.
authors.forename: Marylise
authors.initials: M
authors.lastname: Duperthuy
authors.forename: Paulina
authors.initials: P
authors.lastname: Schmitt
authors.forename: Edwin
authors.initials: E
authors.lastname: Garzón
authors.forename: Audrey
authors.initials: A
authors.lastname: Caro
authors.forename: Rafael D
authors.initials: RD
authors.lastname: Rosa
authors.forename: Frédérique
authors.initials: F
authors.lastname: Le Roux
authors.forename: Nicole
authors.initials: N
authors.lastname: Lautrédou-Audouy
authors.forename: Patrice
authors.initials: P
authors.lastname: Got
authors.forename: Bernard
authors.initials: B
authors.lastname: Romestand
authors.forename: Julien
authors.initials: J
authors.lastname: de Lorgeril
authors.forename: Sylvie
authors.initials: S
authors.lastname: Kieffer-Jaquinod
authors.forename: Evelyne
authors.initials: E
authors.lastname: Bachère
authors.forename: Delphine
authors.initials: D
authors.lastname: Destoumieux-Garzón
mesh_terms: D018829:Adhesins, Bacterial / Q000378:metabolism*; D000704:Analysis of Variance; D000818:Animals; D002853:Chromatography, Liquid; D049896:Crassostrea / Q000276:immunology / Q000382:microbiology*; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D005602:France; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006434:Hemocytes / Q000382:microbiology*; D054884:Host-Pathogen Interactions; D007113:Immunity, Innate / Q000276:immunology*; D018613:Microscopy, Confocal; D016133:Polymerase Chain Reaction; D018272:Porins / Q000378:metabolism*; D018709:Statistics, Nonparametric; D013482:Superoxide Dismutase / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014733:Vibrio / Q000378:metabolism* / Q000472:pathogenicity*
chemical_list: D018829:Adhesins, Bacterial; D018272:Porins; D049452:Green Fluorescent Proteins; D013482:Superoxide Dismutase