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Sayed IM, Sahan AZ, Venkova T, Chakraborty A, Mukhopadhyay D, Bimczok D, Beswick EJ, Reyes VE, Pinchuk I, Sahoo D, Ghosh P, Hazra TK, Das S. Helicobacter pylori infection downregulates the DNA glycosylase NEIL2, resulting in increased genome damage and inflammation in gastric epithelial cells. J Biol Chem 2020; 295:11082-11098. [PMID: 32518160 DOI: 10.1074/jbc.ra119.009981] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 05/30/2020] [Indexed: 01/08/2023] Open
Abstract
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.
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Affiliation(s)
- Ibrahim M Sayed
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Ayse Z Sahan
- Department of Pathology, University of California San Diego, San Diego, California, USA
| | - Tatiana Venkova
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | | | - Diane Bimczok
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
| | - Ellen J Beswick
- Department of Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Victor E Reyes
- Department of Pediatrics, University of Texas Medical Branch, Galveston, Texas, USA
| | - Irina Pinchuk
- College of Medicine, Penn State Health Milton S. Hershey Medical Center, Hershey, Pennsylvania, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, San Diego, California, USA.,Department of Computer Science and Engineering, Jacob's School of Engineering, San Diego, California, USA
| | - Pradipta Ghosh
- Department of Medicine and Cellular and Molecular Medicine, John and Rebecca Moore Cancer Center, University of California San Diego, San Diego, California, USA
| | - Tapas K Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, San Diego, California, USA
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