title: Inflammatory effects of Edwardsiella ictaluri lipopolysaccharide modifications in catfish gut.
abstract: Bacterial lipopolysaccharides (LPS) are structural components of the outer membranes of Gram-negative bacteria and also are potent inducers of inflammation in mammals. Higher vertebrates are extremely sensitive to LPS, but lower vertebrates, like fish, are resistant to their systemic toxic effects. However, the effects of LPS on the fish intestinal mucosa remain unknown. Edwardsiella ictaluri is a primitive member of the Enterobacteriaceae family that causes enteric septicemia in channel catfish (Ictalurus punctatus). E. ictaluri infects and colonizes deep lymphoid tissues upon oral or immersion infection. Both gut and olfactory organs are the primary sites of invasion. At the systemic level, E. ictaluri pathogenesis is relatively well characterized, but our knowledge about E. ictaluri intestinal interaction is limited. Recently, we observed that E. ictaluri oligo-polysaccharide (O-PS) LPS mutants have differential effects on the intestinal epithelia of orally inoculated catfish. Here we evaluate the effects of E. ictaluri O-PS LPS mutants by using a novel catfish intestinal loop model and compare it to the rabbit ileal loop model inoculated with Salmonella enterica serovar Typhimurium LPS. We found evident differences in rabbit ileal loop and catfish ileal loop responses to E. ictaluri and S. Typhimurium LPS. We determined that catfish respond to E. ictaluri LPS but not to S. Typhimurium LPS. We also determined that E. ictaluri inhibits cytokine production and induces disruption of the intestinal fish epithelia in an O-PS-dependent fashion. The E. ictaluri wild type and ΔwibT LPS mutant caused intestinal tissue damage and inhibited proinflammatory cytokine synthesis, in contrast to E. ictaluri Δgne and Δugd LPS mutants. We concluded that the E. ictaluri O-PS subunits play a major role during pathogenesis, since they influence the recognition of the LPS by the intestinal mucosal immune system of the catfish. The LPS structure of E. ictaluri mutants is needed to understand the mechanism of interaction.
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA Microbial Pathogenesis and Vaccinology Laboratory, Nucleus for Microbiology and Immunity, Faculty of Sciences, Universidad Mayor, Huechuraba, Chile School of Life Sciences, Arizona State University, Tempe, Arizona, USA javier.santander@umayor.cl.
authors.forename: Javier
authors.initials: J
authors.lastname: Santander
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA.
authors.forename: Jacquelyn
authors.initials: J
authors.lastname: Kilbourne
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA.
authors.forename: Jie-Yeun
authors.initials: JY
authors.lastname: Park
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
authors.forename: Taylor
authors.initials: T
authors.lastname: Martin
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
authors.forename: Amanda
authors.initials: A
authors.lastname: Loh
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA Microbial Pathogenesis and Vaccinology Laboratory, Nucleus for Microbiology and Immunity, Faculty of Sciences, Universidad Mayor, Huechuraba, Chile Department of Physics, Master Program in Nanoscience, Arizona State University, Tempe, Arizona, USA.
authors.forename: Ignacia
authors.initials: I
authors.lastname: Diaz
authors.affiliation: Mucosal Immunity Laboratory, Nucleus for Microbiology and Immunity, Faculty of Sciences, Universidad Mayor, Huechuraba, Chile.
authors.forename: Robert
authors.initials: R
authors.lastname: Rojas
authors.affiliation: Microbial Pathogenesis and Vaccinology Laboratory, Nucleus for Microbiology and Immunity, Faculty of Sciences, Universidad Mayor, Huechuraba, Chile.
authors.forename: Cristopher
authors.initials: C
authors.lastname: Segovia
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
authors.forename: Dale
authors.initials: D
authors.lastname: DeNardo
authors.affiliation: Center for Infectious Diseases and Vaccinology, The Biodesign Institute, Arizona State University, Tempe, Arizona, USA School of Life Sciences, Arizona State University, Tempe, Arizona, USA.
authors.forename: Roy
authors.initials: R
authors.lastname: Curtiss
mesh_terms: D000818:Animals; D002397:Catfishes; D020610:Edwardsiella ictaluri / Q000235:genetics / Q000276:immunology*; D041981:Gastrointestinal Tract / Q000276:immunology* / Q000473:pathology*; D007249:Inflammation; D007413:Intestinal Mucosa / Q000276:immunology / Q000473:pathology; D008070:Lipopolysaccharides / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology* / Q000633:toxicity*; D009154:Mutation
chemical_list: D008070:Lipopolysaccharides