1. Prokaryotic regulation of epithelial responses by inhibition of IkappaB-alpha ubiquitination.
- Author
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Neish AS, Gewirtz AT, Zeng H, Young AN, Hobert ME, Karmali V, Rao AS, and Madara JL
- Subjects
- Cell Nucleus metabolism, Cysteine Proteinase Inhibitors pharmacology, Cytoskeletal Proteins metabolism, Dimerization, Humans, Inflammation Mediators pharmacology, Interleukin-8 genetics, Interleukin-8 metabolism, Leupeptins pharmacology, Ligases metabolism, NF-KappaB Inhibitor alpha, NF-kappa B genetics, Phosphorylation, Salmonella pathogenicity, Salmonella typhimurium pathogenicity, Salmonella typhimurium physiology, Transcription Factor RelA, Tumor Cells, Cultured, Tumor Necrosis Factor-alpha pharmacology, Ubiquitin-Protein Ligases, Ubiquitins metabolism, beta Catenin, DNA-Binding Proteins metabolism, I-kappa B Proteins, Intestinal Mucosa metabolism, Intestinal Mucosa microbiology, NF-kappa B metabolism, Salmonella physiology, Trans-Activators
- Abstract
Epithelia of the vertebrate intestinal tract characteristically maintain an inflammatory hyporesponsiveness toward the lumenal prokaryotic microflora. We report the identification of enteric organisms (nonvirulent Salmonella strains) whose direct interaction with model human epithelia attenuate synthesis of inflammatory effector molecules elicited by diverse proinflammatory stimuli. This immunosuppressive effect involves inhibition of the inhibitor kappaB/nuclear factor kappaB (IkappaB/NF-kappaB) pathway by blockade of IkappaB-alpha degradation, which prevents subsequent nuclear translocation of active NF-kappaB dimer. Although phosphorylation of IkappaB-alpha occurs, subsequent polyubiquitination necessary for regulated IkappaB-alpha degradation is completely abrogated. These data suggest that prokaryotic determinants could be responsible for the unique tolerance of the gastrointestinal mucosa to proinflammatory stimuli.
- Published
- 2000
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