Research article

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

Kenneth H Mellits¹ , Ian F Connerton¹ , Michael F Loughlin¹ , Peter Clarke² , Julie Smith³ , Eleanor Dillon¹ , Phillippa L Connerton¹ , Francis Mulholland⁴ and Christopher J Hawkey³

¹  Division of Food Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK

²  MyCIB, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, Leicestershire, LE12 5RD, UK

³  Wolfson Digestive Diseases Centre, University Hospital Nottingham, Nottingham, NG7 2UH, UK

⁴  Institute of Food Research, Norwich Research Park, Colney, Norwich, NR4 7UA, UK

author email corresponding author email

BMC Microbiology 2009, 9:28doi:10.1186/1471-2180-9-28

Published:	4 February 2009

Abstract

Background

Campylobacter 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.

Results

RNA 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.

Conclusion

A 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.