Immunostimulatory membrane proteins potentiate H. pylori-induced carcinogenesis by enabling CagA translocation

• Main Authors: Matthew G. Varga, Cecily R. Wood, Julia Butt, Mackenzie E. Ryan, Wei-Cheng You, Kaifeng Pan, Tim Waterboer, Meira Epplein, Carrie L. Shaffer
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2021-01-01
• Series: Gut Microbes
• Subjects: helicobacter pylori; gastric cancer; bacterial pathogenesis; epidemiology; caga
• Online Access: http://dx.doi.org/10.1080/19490976.2020.1862613
• ISSN: 1949-0976; 1949-0984

Infection with Helicobacter pylori is the single greatest risk factor for developing gastric adenocarcinoma. In prospective, population-based studies, seropositivity to the uncharacterized H. pylori proteins Hp0305 and Hp1564 was significantly associated with cancer risk in East Asia. However, the mechanism underlying this observation has not been elucidated. Here, we show that Hp0305 and Hp1564 act in concert with previously ascribed H. pylori virulence mechanisms to orchestrate cellular alterations that promote gastric carcinogenesis. In samples from 546 patients exhibiting premalignant gastric lesions, seropositivity to Hp0305 and Hp1564 was significantly associated with increased gastric atrophy across all stomach conditions. In vitro, depletion of Hp0305 and Hp1564 significantly reduced levels of gastric cell-associated bacteria and markedly impaired the ability of H. pylori to stimulate pro-inflammatory cytokine production. Remarkably, our studies revealed that Hp1564 is required for translocation of the oncoprotein CagA into gastric epithelial cells. Our data provide experimental insight into the molecular mechanisms governing novel H. pylori pathogenicity factors that are strongly associated with gastric disease and highlight the potential of Hp0305 and Hp1564 as robust molecular tools that can improve identification of individuals that are highly susceptible to gastric cancer. We demonstrate that Hp0305 and Hp1564 augment H. pylori-mediated inflammation and gastric cancer risk by promoting key bacteria-gastric cell interactions that facilitate delivery of oncogenic microbial cargo to target cells. Thus, therapeutically targeting microbial interactions driven by Hp0305/Hp1564 may enable focused H. pylori eradication strategies to prevent development of gastric malignancies in high-risk populations.