Nucleotide-binding oligomerization domain 1 and<i>Helicobacter pylori</i>infection: A review

Nucleotide-binding oligomerization domain 1 (NOD1) is an intracellular innate immune sensor for small molecules derived from bacterial cell components. NOD1 activation by its ligands leads to robust production of pro-inflammatory cytokines and chemokines by innate immune cells, thereby mediating mucosal host defense systems against microbes. Chronic gastric infection due to <i>Helicobacter pylori</i> (<i>H. pylori</i>) causes various upper gastrointestinal diseases, including atrophic gastritis, peptic ulcers, and gastric cancer. It is now generally accepted that detection of <i>H. pylori</i> by NOD1 expressed in gastric epithelial cells plays an indispensable role in mucosal host defense systems against this organism. Recent studies have revealed the molecular mechanism by which NOD1 activation caused by <i>H. pylori</i> infection is involved in the development of chronic gastritis and gastric cancer. In this review, we have discussed and summarized how sensing of <i>H. pylori</i> by NOD1 mediates the prevention of chronic gastritis and gastric cancer.