Role of the TRIF-IFN-I pathway in Helicobacter-induced gastric cancer progression in an accelerated murine disease model
Background: Helicobacter pylori (H. pylori) infection is a known cause of many digestive diseases, including gastritis, peptic ulcers, and gastric cancer. However, the underlying mechanism(s)by which H. pylori infection triggers these disorders are still not clearly understood.  Methods: We have developed an accelerated disease progression mouse model, which leverages mice deficient in the myeloid differentiation primary response 88 gene (Myd88-/-) infected with Helicobacter felis (H. felis) Findings: In this study, we found that H. felis-induced inflammation in Myd88-/- mice progressed to high-grade dysplasia, driven by activation of the type I interferon (IFN-I) signaling pathway and upregulation of its downstream targets, IFN-stimulated genes (ISGs). We also observed enrichment of IFN stimulated-response element (ISRE) motifs in the promoters of upregulated genes, further supporting the involvement of this pathway. In contrast, mice deficient in Toll/interleukin-1 receptor (TIR)-domain-containing adaptor inducing interferon-ß (TRIF, TrifLps2) did not progress to severe gastric pathology after H. felis infection, implicating the TRIF signaling pathway in disease pathogenesis and progression. Additionally, analysis of gastric biopsy samples from human gastric cancer patients illustrated that low expression of Myd88 and high expression of Trif were both significantly correlated with poor survival. Interpretation: Our study using an accelerated animal model for gastric cancer and gastric biopsy samples from patients demonstrated that activation of the TRIF-IFN-I signaling pathway promotes Helicobacter-induced disease progression toward severe gastric pathology and gastric cancer development. This represents a potential target for therapeutic intervention, and further exploration may lead to the identification of novel treatment strategies. Overall design: To investigate the role of Myd88 and Trif functions in Helicobacter-induced gastric cancer, RNA-seq expression profiling was conducted on gastric tissue from uninfected and infected tissue from WT, Myd88 KO, Trif KO, and Double KO mice.