BACKGROUND: -induced chronic atrophic gastritis (CAG) is a significant health concern. The role of microsomal triglyceride transfer protein (MTTP) in CAG progression has not been explored, presenting a critical knowledge gap in understanding -induced CAG pathogenesis. METHODS: Sprague-Dawley rats and gastric epithelial cell line were infected with H. pylori to build CAG model. The mRNA and protein levels of DNA methyltransferase 1 (DNMT1), MTTP, and glutathione peroxidase 4 (GPX4) were measured by quantitative real-time PCR (RT-qPCR) and western blotting, respectively. Moreover, the localization of DNMT1 and MTTP was detected via immunohistochemistry. Furthermore, the pathological changes of gastric tissue were analyzed by HE staining. RESULTS: The MTTP expression was downregulated in CAG. Moreover, overexpression of MTTP in gastric epithelial cells could suppress the inflammatory response induced by infection and ferroptosis by upregulating GPX4 expression. In addition, DNMT1 expression was upregulated in CAG and was negatively correlated with MTTP expression. Furthermore, DNMT1 could target MTTP promoter to activate methylation and downregulate MTTP expression. CONCLUSION: DNMT1 downregulated the MTTP expression through methylation, and thus mediate inflammasome-ferroptosis processes via GPX4 in the -induced CAG.