title: Campylobacter jejuni increases flagellar expression and adhesion of noninvasive Escherichia coli: effects on enterocytic Toll-like receptor 4 and CXCL-8 expression.
abstract: Campylobacter jejuni is the most common cause of bacterium-induced gastroenteritis, and while typically self-limiting, C. jejuni infections are associated with postinfectious intestinal disorders, including flares in patients with inflammatory bowel disease and postinfectious irritable bowel syndrome (PI-IBS), via mechanisms that remain obscure. Based on the hypothesis that acute campylobacteriosis may cause pathogenic microbiota dysbiosis, we investigated whether C. jejuni may activate dormant virulence genes in noninvasive Escherichia coli and examined the epithelial pathophysiological consequences of these alterations. Microarray and quantitative real-time PCR analyses revealed that E. coli adhesin, flagellum, and hemolysin gene expression were increased when E. coli was exposed to C. jejuni-conditioned medium. Increased development of bacterial flagella upon exposure to live C. jejuni or C. jejuni-conditioned medium was observed under transmission electron microscopy. Atomic force microscopy demonstrated that the forces of bacterial adhesion to colonic T84 enterocytes, and the work required to rupture this adhesion, were significantly increased in E. coli exposed to C. jejuni-conditioned media. Finally, C. jejuni-modified E. coli disrupted TLR4 gene expression and induced proinflammatory CXCL-8 gene expression in colonic enterocytes. Together, these data suggest that exposure to live C. jejuni, and/or to its secretory-excretory products, may activate latent virulence genes in noninvasive E. coli and that these alterations may directly trigger proinflammatory signaling in intestinal epithelia. These observations shed new light on mechanisms that may contribute, at least in part, to postcampylobacteriosis inflammatory disorders.
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Kristen L
authors.initials: KL
authors.lastname: Reti
authors.affiliation: Alberta Agriculture and Rural Development, Lethbridge, Alberta, Canada.
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Tymensen
authors.affiliation: Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Shevaun P
authors.initials: SP
authors.lastname: Davis
authors.affiliation: Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.
authors.forename: Matthias W
authors.initials: MW
authors.lastname: Amrein
authors.affiliation: Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada aburet@ucalgary.ca.
authors.forename: Andre G
authors.initials: AG
authors.lastname: Buret
mesh_terms: D016123:Campylobacter jejuni / Q000378:metabolism* / Q000472:pathogenicity; D002460:Cell Line; D017077:Culture Media, Conditioned / Q000494:pharmacology*; D020895:Enterocytes / Q000187:drug effects* / Q000276:immunology / Q000382:microbiology; D004926:Escherichia coli / Q000187:drug effects / Q000254:growth & development / Q000472:pathogenicity; D005407:Flagella / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation; D054884:Host-Pathogen Interactions; D006801:Humans; D016209:Interleukin-8 / Q000819:agonists / Q000235:genetics / Q000276:immunology*; D015398:Signal Transduction; D013559:Symbiosis; D051197:Toll-Like Receptor 4 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology*; D014774:Virulence
chemical_list: C508606:CXCL8 protein, human; D017077:Culture Media, Conditioned; D016209:Interleukin-8; C495345:TLR4 protein, human; D051197:Toll-Like Receptor 4