NOD1 contributes to mouse host defense against Helicobacter pylori via induction of type I IFN and activation of the ISGF3 signaling pathway
Tomohiro Watanabe, … , Atsushi Kitani, Warren Strober
Tomohiro Watanabe, … , Atsushi Kitani, Warren Strober
Published April 12, 2010
Citation Information: J Clin Invest. 2010;120(5):1645-1662. https://doi.org/10.1172/JCI39481.
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Research Article Immunology

NOD1 contributes to mouse host defense against Helicobacter pylori via induction of type I IFN and activation of the ISGF3 signaling pathway

Abstract

Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular epithelial cell protein known to play a role in host defense at mucosal surfaces. Here we show that a ligand specific for NOD1, a peptide derived from peptidoglycan, initiates an unexpected signaling pathway in human epithelial cell lines that results in the production of type I IFN. Detailed analysis revealed the components of the signaling pathway. NOD1 binding to its ligand triggered activation of the serine-threonine kinase RICK, which was then able to bind TNF receptor–associated factor 3 (TRAF3). This in turn led to activation of TANK-binding kinase 1 (TBK1) and IκB kinase ε (IKKε) and the subsequent activation of IFN regulatory factor 7 (IRF7). IRF7 induced IFN-β production, which led to activation of a heterotrimeric transcription factor complex known as IFN-stimulated gene factor 3 (ISGF3) and the subsequent production of CXCL10 and additional type I IFN. In vivo studies showed that mice lacking the receptor for IFN-β or subjected to gene silencing of the ISGF3 component Stat1 exhibited decreased CXCL10 responses and increased susceptibility to Helicobacter pylori infection, phenotypes observed in NOD1-deficient mice. These studies thus establish that NOD1 can activate the ISGF3 signaling pathway that is usually associated with protection against viral infection to provide mice with robust type I IFN–mediated protection from H. pylori and possibly other mucosal infections.

Authors

Tomohiro Watanabe, Naoki Asano, Stefan Fichtner-Feigl, Peter L. Gorelick, Yoshihisa Tsuji, Yuko Matsumoto, Tsutomu Chiba, Ivan J. Fuss, Atsushi Kitani, Warren Strober

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Figure 3

NOD1-induced interaction of TRAF3 with RICK or TBK1.

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NOD1-induced interaction of TRAF3 with RICK or TBK1. (A) HEK293 cells we...
(A) HEK293 cells were transfected with 2 μg of V5-tagged RICK cDNA and/or 2 μg of TRAF3 cDNA. Lysates were immunoprecipitated with anti-V5 beads followed by immunoblotting with anti-TRAF3 Ab. (B and C) Physical interaction between RICK and TRAF3 (B) or between TRAF3 and TBK1 (C). HT-29 cells or THP1 cells untreated (B, left panel) or treated with IFN-γ (100 ng/ml) (right panel) for 24 hours were left unstimulated (medium, 100 μg/ml) or were stimulated with iE-DAP (10 μg/ml) or MDP (100 μg/ml) for 1 hour. Lysates were immunoprecipitated with anti-RICK Ab or anti-TRAF3 Ab, followed by immunoblotting with anti-TRAF3 Ab or anti-TBK1 Ab. (D) IP-10 production by iE-DAP–stimulated HT-29 cells transfected with TBK1 or IKKε siRNA. Top: expression of TBK1 and IKKε in HT-29 cells transfected with TBK1 or IKKε siRNA. Bottom: IP-10 production of transfected cells. HT-29 cells were transfected with TBK1 siRNA, IKKε siRNA, or control siRNA (20 nM each) and after 24 hours cells were cultured for a further 48 hours with iE-DAP (100 μg/ml) or TNF (100 ng/ml). *P < 0.05; **P < 0.01 compared with cells transfected with control siRNA. (E) Wild-type (Tbk1+/+Ikke+/+) or TBK1/IKKε–double-deficient (Tbk1–/–Ikke–/–) MEFs (106/ml) were stimulated with iE-DAP (100 μg/ml) or TNF (10 ng/ml) for 24 hours. Cultured supernatants were subjected to an IP-10 assay. Results are expressed as mean ± SD. **P < 0.01 compared with wild-type cells.