Probiotics prevent enterohaemorrhagic Escherichia coli O157:H7-mediated inhibition of interferon-gamma-induced tyrosine phosphorylation of STAT-1.

Abstract

Enterohaemorrhagic Escherichia coli (EHEC) O157:H7 inhibits interferon (IFN)-gamma-stimulated tyrosine phosphorylation of signal transducer and activator of transcription (STAT)-1 in epithelial cells. We determined the effects of probiotics on EHEC-mediated disruption of IFN-gamma-stimulated STAT-1 activation in epithelial cell lines. Confluent Intestine 407, HEp-2 and Caco-2 epithelial cells were pre-treated (3 h) with either probiotics or surface-layer proteins derived from Lactobacillus helveticus R0052 prior to infection with EHEC O157:H7 strain CL56 (m.o.i. 100:1, 6 h, 37 degrees C in 5% CO2). Subsequently, cells were washed and stimulated with human recombinant IFN-gamma (50 ng ml(-1), 0.5 h, 37 degrees C) followed by whole-cell protein extraction and immunoblotting for tyrosine-phosphorylated STAT-1. Relative to uninfected cells, STAT-1-activation was reduced after EHEC O157:H7 infection. Pre-incubation with the probiotic L. helveticus R0052 followed by EHEC infection abrogated pathogen-mediated disruption of IFN-gamma-STAT-1 signalling. As determined using Transwell inserts, probiotic-mediated protection was independent of epithelial cell contact. In contrast, pre-incubation with boiled L. helveticus R0052, an equal concentration of viable Lactobacillus rhamnosus R0011, or surface-layer proteins (0.14 mg ml(-1)) did not restore STAT-1 signalling in EHEC-infected cells. The viable probiotic agent L. helveticus R0052 prevented EHEC O157:H7-mediated subversion of epithelial cell signal transduction responses.

• Authors: Narveen Jandu, Zoë Jingjing Zeng, Kathene C Johnson-Henry, Philip M Sherman
• Journal: Microbiology (Reading, England) (Microbiology (Reading)) Vol. 155 Issue Pt 2 Pg. 531-540 (Feb 2009) ISSN: 1350-0872 [Print] England
• PMID: 19202101 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Bacterial Proteins
• STAT1 Transcription Factor
• Tyrosine
• Interferon-gamma

Topics

• Bacterial Proteins (pharmacology)
• Cell Line
• Down-Regulation
• Epithelial Cells (metabolism, microbiology)
• Escherichia coli Infections (metabolism, microbiology, prevention & control)
• Escherichia coli O157 (physiology)
• Humans
• Interferon-gamma (metabolism)
• Lactobacillus helveticus (chemistry, physiology)
• Phosphorylation (drug effects)
• Probiotics (chemistry, pharmacology)
• STAT1 Transcription Factor (metabolism)
• Signal Transduction (drug effects)
• Tyrosine (metabolism)