BET Inhibition Attenuates Helicobacter pylori –Induced Inflammatory Response by Suppressing Inflammatory Gene Transcription and Enhancer Activation

Abstract

Helicobacter pylori infection causes chronic gastritis and peptic ulceration. H. pylori–initiated chronic gastritis is characterized by enhanced expression of many NF-κB–regulated inflammatory cytokines. Brd4 has emerged as an important NF-κB regulator and regulates the expression of many NF-κB–dependent inflammatory genes. In this study, we demonstrated that Brd4 was not only actively involved in H. pylori–induced inflammatory gene mRNA transcription but also H. pylori–induced inflammatory gene enhancer RNA (eRNA) synthesis. Suppression of H. pylori–induced eRNA synthesis impaired H. pylori–induced mRNA synthesis. Furthermore, H. pylori stimulated NF-κB–dependent recruitment of Brd4 to the promoters and enhancers of inflammatory genes to facilitate the RNA polymerase II–mediated eRNA and mRNA synthesis. Inhibition of Brd4 by JQ1 attenuated H. pylori–induced eRNA and mRNA synthesis for a subset of NF-κB–dependent inflammatory genes. JQ1 also inhibited H. pylori–induced interaction between Brd4 and RelA and the recruitment of Brd4 and RNA polymerase II to the promoters and enhancers of inflammatory genes. Finally, we demonstrated that JQ1 suppressed inflammatory gene expression, inflammation, and cell proliferation in H. pylori–infected mice. These studies highlight the importance of Brd4 in H. pylori–induced inflammatory gene expression and suggest that Brd4 could be a potential therapeutic target for the treatment of H. pylori–triggered inflammatory diseases and cancer.