Helicobacter pylori infection downregulates the DNA glycosylase NEIL2, resulting in increased genome damage and inflammation in gastric epithelial cells

Ibrahim M. Sayed, Ayse Z. Sahan, Tatiana Venkova, Anirban Chakraborty, Dibyabrata Mukhopadhyay, Diane Bimczok, Ellen J. Beswick, Victor E. Reyes, Irina Pinchuk, Debashis Sahoo, Pradipta Ghosh, Tapas K. Hazra, Soumita Das

Research output: Contribution to journalArticlepeer-review

26 Scopus citations


Infection with the Gram-negative, microaerophilic bacterium Helicobacter pylori induces an inflammatory response and oxidative DNA damage in gastric epithelial cells that can lead to gastric cancer (GC). However, the underlying pathogenic mechanism is largely unclear. Here, we report that the suppression of Nei-like DNA glycosylase 2 (NEIL2), a mammalian DNA glycosylase that specifically removes oxidized bases, is one mechanism through which H. pylori infection may fuel the accumulation of DNA damage leading to GC. Using cultured cell lines, gastric biopsy specimens, primary cells, and human enteroid-derived monolayers from healthy human stomach, we show that H. pylori infection greatly reduces NEIL2 expression. The H. pylori infection-induced downregulation of NEIL2 was specific, as Campylobacter jejuni had no such effect. Using gastric organoids isolated from the murine stomach in coculture experiments with live bacteria mimicking the infected stomach lining, we found that H. pylori infection is associated with the production of various inflammatory cytokines. This response was more pronounced in Neil2 knockout (KO) mouse cells than in WT cells, suggesting that NEIL2 suppresses inflammation under physiological conditions. Notably, the H. pylori-infected Neil2-KO murine stomach exhibited more DNA damage than the WT. Furthermore, H. pylori-infected Neil2-KO mice had greater inflammation and more epithelial cell damage. Computational analysis of gene expression profiles of DNA glycosylases in gastric specimens linked the reduced Neil2 level to GC progression. Our results suggest that NEIL2 downregulation is a plausible mechanism by which H. pylori infection impairs DNA damage repair, amplifies the inflammatory response, and initiates GC.

Original languageEnglish
Pages (from-to)11082-11098
Number of pages17
JournalJournal of Biological Chemistry
Issue number32
StatePublished - Aug 7 2020

Bibliographical note

Funding Information:
Funding and additional information—This work was supported, in whole or in part, by National Institutes of Health grants DK107585 and DK099275, C3 Padre Pedal MCC pilot grant (to S. D.), R01 NS073976 (to T. H.), R01HL145477 (T. K. H.), W81XWH-18-1-0743 (to T. K. H.), R01 AI141630 (to P. G.), R01-GM138385 (to D. S.), and DoD CA150375 (to V. E. R.). The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Publisher Copyright:
© 2020 Sayed et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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