| Autor: |
Friis, Lorna M., Keelan, Monika, Taylor, Diane E. |
| Zdroj: |
Infection and Immunity; April 2009, Vol. 77 Issue: 4 p1553-1560, 8p |
| Abstrakt: |
ABSTRACTGastrointestinal disease caused by Campylobacter jejuniis characterized by localized inflammation and the destruction of the epithelial cell barrier that forms host innate protection against pathogens. This can lead to an imbalance in fluid transport across the gastrointestinal tract, resulting in severe diarrhea. The mechanisms of host cell receptor recognition of C. jejuniand downstream immune signaling pathways leading to this inflammatory disease, however, remain unclear. The aim of this study was to analyze the mechanisms involved in C. jejuniinduction of the acute-phase inflammatory response regulator interleukin-6 (IL-6). Polarized intestinal epithelial Caco-2 monolayers responded to infections with Salmonella entericaserovar Typhimurium and eight isolates of C. jejuniby an increase in levels of expression and secretion of IL-6. No such IL-6 response, however, was produced upon infection with the human commensal organism Lactobacillus rhamnosusGG. The IL-6 signaling pathway was further characterized using short interfering RNA complexes to block gene expression. The inhibition of myeloid differentiation primary response protein 88 (MyD88) expression in this manner did not affect C. jejuni-induced IL-6 secretion, suggesting a MyD88-independent route to IL-6 signal transduction in C. jejuni-infected human epithelial cells. However, a significant reduction in levels of IL-6 was evident in the absence of Toll-like receptor 2 (TLR-2) expression, implying a requirement for TLR-2 in C. jejunirecognition. Caco-2 cells were also treated with heat-inactivated and purified membrane components of C. jejunito isolate the factor responsible for triggering IL-6 signaling. The results demonstrate that C. jejunisurface polysaccharides induce IL-6 secretion from intestinal epithelial cells via TLR-2 in a MyD88-independent manner. |
| Databáze: |
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