Induction of a chemoattractant transcriptional response by a Campylobacter jejuni boiled cell extract in colonocytes

Abstract

BackgroundCampylobacter jejuni, the commonest cause of bacterial diarrhoea worldwide, can also induce colonic inflammation. To understand how a previously identified heat stable component contributes to pro-inflammatory responses we used microarray and real-time quantitative PCR to investigate the transcriptional response to a boiled cell extract of Campylobacter jejuni NCTC 11168.ResultsRNA was extracted from the human colonocyte line HCA-7 (clone 29) after incubation for 6 hours with Campylobacter jejuni boiled cell extract and was used to probe the Affymetrix Human Genome U133A array. Genes differentially affected by Campylobacter jejuni boiled cell extract were identified using the Significance Score algorithm of the Bioconductor software suite and further analyzed using the Ingenuity Pathway Analysis program. The chemokines CCL20, CXCL3, CXCL2, Interleukin 8, CXCL1 and CXCL6 comprised 6 of the 10 most highly up-regulated genes, all with Significance Scores ≥ 10. Members of the Tumor Necrosis Factor α/Nuclear Factor-κB super-family were also significantly up-regulated and involved in the most significantly regulated signalling pathways (Death receptor, Interleukin 6, Interleukin 10, Toll like receptor, Peroxisome Proliferator Activated Receptor-γ and apoptosis). Ingenuity Pathway Analysis also identified the most affected functional gene networks such as cell movement, gene expression and cell death. In contrast, down-regulated genes were predominantly concerned with structural and metabolic functions.ConclusionA boiled cell extract of Campylobacter jejuni has components that can directly switch the phenotype of colonic epithelial cells from one of resting metabolism to a pro-inflammatory one, particularly characterized by increased expression of genes for leukocyte chemoattractant molecules.

Interaction between Campylobacter and intestinal epithelial cells leads to a different proinflammatory response in human and porcine host

“…Thus, the commensal behavior of Campylobacter in porcine host could be explaining the lack of proinflammatory response observed in IPI-2I and IPEC-J2. Although the important role of molecules such as CCL2 and CXCL2 as potential regulators of monocyte recruitment and polymorphonuclear leukocytes in human campylobacteriosis has been described (Bakhiet et al, 2004;Mellits et al, 2009), our data show that CCL2 and CXCL2 mRNA expression were similar in human and porcine cells. Therefore, our results suggest that CCL2 and CXCL2 did not play an important role in early immune response against Campylobacter.…”

Disruption of colonic barrier function and induction of mediator release by strains of Campylobacter jejuni that invade epithelial cells

“…We chose to use HCA7 cells in preference to CaCo2 cells because they have a differentiated large rather than small bowel phenotype and because they are capable of expressing COX-2 under induction conditions. Our data suggest that this is an informative model and cell line to study disease pathogenesis and signaling mechanisms [40] .…”

“…As yet it is uncertain whether intracellular invasion directly causes the associated release of IL-8 and PGE2, or whether this is a secondary consequence of cell death. A direct specific effect is possible since we have reported that IL-8 synthesis and PGE2 release from epithelial monolayers also occur in response to treatment with a boiled cell-free extract of C. jejuni [38] , with induction of COX-2 [39] and activation of nuclear factor-κB (NF-κB) and other relevant signaling pathways [40] . Enhanced release of IL-8 and other chemokines would play an important role in chemoattraction of neutrophils that characterizes some clinical infections with C. jejuni.…”

“…This increase in bradykinin-induced chloride secretion may therefore occur by prostaglandin-independent mechanisms. Direct epithelial action, via cAMP, cGMP, calcium mobilization, or induction of galanin or inducible nitric oxide are alternative mechanisms that are activated directly by bacterial enterotoxins or via signaling mechanisms that include NF-κB, which we and others have shown are upregulated by components of C. jejuni [24][25][26][27][40][41][42][43] . Destruction of the monolayer by strains that did invade epithelial cells and stimulate prostaglandin synthesis makes it difficult to evaluate whether enhanced prostaglandin synthesis by epithelial cells contributed to secretory diarrhea in these cases.…”

TLR1-induced chemokine production is critical for mucosal immunity against Yersinia enterocolitica

“…Previous studies have shown that CCL20 production and recruitment of CCR6+ DC occurs during infection in mucosal sites, such as the gut 20,41,42 and lung 43 . This migration and activation of mucosal DC has also been shown to be an important host strategy for the induction of pathogen-specific effector T cell responses 18,20 .…”