The pathogenic potential of Campylobacter concisus strains associated with chronic intestinal diseases

• Published in: PloS one Vol. 6; no. 12; p. e29045
• Main Authors: Kaakoush, Nadeem O, Deshpande, Nandan P, Wilkins, Marc R, Tan, Chew Gee, Burgos-Portugal, Jose A, Raftery, Mark J, Day, Andrew S, Lemberg, Daniel A, Mitchell, Hazel
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14-12-2011; Public Library of Science (PLoS)
• Subjects: Activation; Adolescent; Analysis; Bacteria; Bacterial Adhesion; Biological response modifiers; Biology; Biopsy; Biotechnology; Caco-2 Cells; Campylobacter; Campylobacter - genetics; Campylobacter - isolation & purification; Campylobacter - pathogenicity; Campylobacter - ultrastructure; Campylobacter Infections - immunology; Campylobacter Infections - microbiology; Campylobacter Infections - pathology; Child; Child, Preschool; Children; Children & youth; Chronic Disease; Colon; Crohn's Disease; Crohns disease; Cytokines; Cytokines - biosynthesis; Diseases; Electrophoresis, Gel, Two-Dimensional; Enzyme-linked immunosorbent assay; Epithelial cells; Female; Flagella; Functional analysis; Fungal infections; Gastroenteritis; Gastroenterology; Genes, Bacterial - genetics; Genomic analysis; Host-Pathogen Interactions; Humans; Immune response; Immune system; Infections; Inflammation; Inflammatory bowel disease; Interferon; Interleukin 12; Intestinal Diseases - immunology; Intestinal Diseases - microbiology; Intestinal Diseases - pathology; Intestinal Mucosa - microbiology; Intestinal Mucosa - pathology; Intestinal Mucosa - ultrastructure; Intestine; Male; Mass spectrometry; Medical research; Medicine; Membrane ruffling; Models, Biological; Mucin; Mucins - metabolism; Mucosa; NF-κB protein; Oxidative stress; Pathogenesis; Patients; Phenotype; Plasmids - metabolism; Polymerase Chain Reaction; Proteasomes; Proteins; Proteome - metabolism; Proteomics; Rodents; Scientific imaging; Small intestine; Strains (organisms); Studies; Australia; New South Wales Australia
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0029045

Campylobacter concisus has garnered increasing attention due to its association with intestinal disease, thus, the pathogenic potential of strains isolated from different intestinal diseases was investigated. A method to isolate C. concisus was developed and the ability of eight strains from chronic and acute intestinal diseases to adhere to and invade intestinal epithelial cells was determined. Features associated with bacterial invasion were investigated using comparative genomic analyses and the effect of C. concisus on host protein expression was examined using proteomics. Our isolation method from intestinal biopsies resulted in the isolation of three C. concisus strains from children with Crohn's disease or chronic gastroenteritis. Four C. concisus strains from patients with chronic intestinal diseases can attach to and invade host cells using mechanisms such as chemoattraction to mucin, aggregation, flagellum-mediated attachment, "membrane ruffling", cell penetration and damage. C. concisus strains isolated from patients with chronic intestinal diseases have significantly higher invasive potential than those from acute intestinal diseases. Investigation of the cause of this increased pathogenic potential revealed a plasmid to be responsible. 78 and 47 proteins were upregulated and downregulated in cells infected with C. concisus, respectively. Functional analysis of these proteins showed that C. concisus infection regulated processes related to interleukin-12 production, proteasome activation and NF-κB activation. Infection with all eight C. concisus strains resulted in host cells producing high levels of interleukin-12, however, only strains capable of invading host cells resulted in interferon-γ production as confirmed by ELISA. These findings considerably support the emergence of C. concisus as an intestinal pathogen, but more significantly, provide novel insights into the host immune response and an explanation for the heterogeneity observed in the outcome of C. concisus infection. Moreover, response to infection with invasive strains has substantial similarities to that observed in the inflamed mucosa of Crohn's disease patients.