Chronic mucosal pathogens have evolved multiple strategies to manipulate the host immune response; consequently, microbes contribute to the development of >2 million cases of
cancer/year. Gastric
adenocarcinoma is the fourth leading cause of
cancer-related death and Helicobacter pylori confers the highest risk for this disease. Gastric innate immune effectors can either eliminate bacteria or mobilize adaptive immune responses including
Toll-like receptors (TLRs), and cytosolic
DNA sensor/adaptor
proteins (e.g., stimulator of
interferon genes,
STING). The H. pylori strain-specific cag
type IV secretion system (T4SS) augments
gastric cancer risk and translocates
DNA into epithelial cells where it activates the microbial
DNA sensor TLR9 and suppresses injury in vivo; however, the ability of H. pylori to suppress additional
nucleic acid PRRs within the context of chronic gastric
inflammation and injury remains undefined. In this study, in vitro and ex vivo experiments identified a novel mechanism through which H. pylori actively suppresses
STING and RIG-I signaling via downregulation of IRF3 activation. In vivo, the use of genetically deficient mice revealed that Th17 inflammatory responses are heightened following H. pylori
infection within the context of
Sting deficiency in conjunction with increased expression of a known host immune regulator, Trim30a. This novel mechanism of immune suppression by H. pylori is likely a critical component of a finely tuned rheostat that not only regulates the initial innate immune response, but also drives chronic gastric
inflammation and injury.