IL-1beta expression in Int407 is induced by flagellin of Vibrio cholerae through TLR5 mediated pathway.

Abstract

Vibrio cholerae, a noninvasive enteric bacterium, causing inflammatory diarrheal disease cholera, is associated with the secretion of proinflamammatory cytokines including IL-1beta in cultured epithelial cells. Incubation of Int407 with live V. cholerae resulted in increased IL-1beta mRNA expression as early as 2h of infection, reached a peak at approximately 3.5h and decreased thereafter. The identity of the effector molecule(s) is largely unknown. The bacterial culture supernatant showed IL-1beta stimulating activity. An engineered aflagellate V. cholerae flaA mutant (O395FLAN) resulted in highly reduced level of IL-1beta expression in Int407. The crude flagellar protein of V. cholerae as well as recombinant FlaA induced IL-1beta expression in Int407. Infection of Toll-like receptor 5 (TLR5) transfected HeLa cells with O395FLAN showed reduced expression of IL-1beta compared to wild-type. Unlike wild-type V. cholerae, O395FLAN did not activate the NF-kappaB while the recombinant flagellin could activate NF-kappaB. Finally, the mitogen activated protein kinases (ERK1 and 2, p38) were phosphorylated in wild-type and recombinant flagellin treated Int407 cells and inhibition of the p38 and ERK pathways significantly decreased the IL-1beta response induced by wild-type V. cholerae as well as recombinant flagellin. Our data clearly indicate that flagellin of V. cholerae could induce IL-1beta expression by recognizing TLR5 that activate NF-kappaB and MAP kinase in Int407.

• Authors: Arunava Bandyopadhaya, Madhubanti Sarkar, Keya Chaudhuri
• Journal: Microbial pathogenesis (Microb Pathog) Vol. 44 Issue 6 Pg. 524-36 (Jun 2008) ISSN: 0882-4010 [Print] England
• PMID: 18314303 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Culture Media
• Interleukin-1beta
• NF-kappa B
• RNA, Messenger
• Recombinant Proteins
• TLR5 protein, human
• Toll-Like Receptor 5
• Flagellin
• flaA protein, bacteria
• Mitogen-Activated Protein Kinases

Topics

• Cells, Cultured
• Cholera (immunology, microbiology, physiopathology)
• Culture Media (chemistry)
• Epithelial Cells (immunology, microbiology, physiology)
• Flagellin (genetics, immunology)
• Gene Expression
• HeLa Cells
• Humans
• Interleukin-1beta (metabolism)
• Mitogen-Activated Protein Kinases (metabolism)
• NF-kappa B (metabolism)
• RNA, Messenger (genetics, metabolism)
• Recombinant Proteins (genetics, immunology)
• Signal Transduction
• Toll-Like Receptor 5 (genetics, metabolism)
• Vibrio cholerae (genetics, immunology)