PROJECT SUMMARY Helicobacter pylori infection is commonly associated with several gastric diseases including gastritis, peptic ulcer disease, lymphoma of the mucosa-associated lymphoid tissue, and gastric adenocarcinoma. H. pylori has evolved various mechanisms to evade the host innate immune response, and as a result, these bacteria can thrive for decades in the gastric mucosa. Chronic infection elicits the continuous generation of reactive oxygen species (ROS) by neutrophils and gastric epithelial cells. Elevated levels of ROS can damage macromolecules, and previous studies have focused on how ROS mediate DNA damage during infection. However, ROS can also generate oxidative post-translational modifications on host proteins containing redox-sensitive cysteines that regulate important cellular functions. Our lab previously performed a chemical proteomic screen to identify cysteines in host proteins that exhibit decreased reactivity during H. pylori infection of human gastric cancer cells. This proposal will focus on two ribosomal proteins, uL14 and eS27, which contain cysteine residues that were among the top hits from this screen. Host translational inhibition is a well-characterized response to infection by several microbes, and Aim 1 of this proposal will elucidate whether ribosome biogenesis and translational function are similarly affected during H. pylori infection. Aim 2 will focus on characterizing how the reactivity of the specific cysteines Cys125 of uL14 and Cys77 of eS27 contributes to the cellular localization and interactions of the ribosomal proteins. Overall, this proposal will provide insight into how redox regulation of host ribosomal proteins affects their function and expand our understanding of host cellular processes that are modulated by H. pylori infection.

PROJECT NARRATIVE: Helicobacter pylori is a gastric pathogen that colonizes the gastric mucosa of more than half of the global population and is a major risk factor for several gastric pathologies including peptic-ulcer disease and gastric adenocarcinoma. The goal of this project is to determine how reactive oxygen species, a hallmark of H. pylori infection, oxidize host ribosomal proteins and impact their functions. The results of this study will further our knowledge of how H. pylori infection modulates host cellular events and identify signaling axes that could be leveraged for the prevention and treatment of H. pylori-induced gastric pathologies.