CagA+ Helicobacter pylori induces proliferation and expression of Sonic hedgehog in fundic organoid model (1119.4)

Abstract

Helicobacter pylori (H. pylori) infection leads to aberrant cell proliferation and dysregulated Hedgehog signaling in the stomach. The organoid model is an emerging in vitro system whereby isolated gastric glands are cultured into three‐dimensional spheres that express cells present in the original tissue. This model allows for the study of epithelial responses to infection in a system independent of recruited inflammatory cells. We hypothesize that H. pylori induces cell proliferation and acute expression of Sonic hedgehog (Shh) in the fundic organoid model in the absence of recruited circulating host factors. Fundic organoids were generated from dissociated gastric glands of control or transgenic mice lacking Shh expression in the parietal cell (PC‐ShhKO). Expression of mature cell lineage markers was confirmed by RT‐PCR and immunofluorescence staining. Colonization and epithelial attachment was confirmed by silver stain, live‐imaging and quantitative re‐culture. Organoids injected with cagA+ but not cagA‐deficient H. pylori had significantly increased cell proliferation as measured by EdU staining. Proliferation was associated with c‐Met phosphorylation as determined by western blot. H. pylori induced Shh at 1 day post‐injection in control organoids but not those generated from PC‐ShhKO mice, and this effect was inhibited by NFκB inhibition. Inhibition of CXCL1/2 signaling, a putative mediator of Shh induction, did not block H. pylori‐induced Shh expression. This report demonstrates a uniquely beneficial in vitro approach to study the host response to H. pylori interactions with the gastric epithelium, independent of recruited hematopoietic factors. Fundic organoids recapitulate the in vivo responses to H. pylori of cell proliferation and Shh induction and provide mechanistic insight demonstrating 1) cagA dependence and c‐Met phosphorylation association with H. pylori‐induced proliferation and 2) NFκB requirement for H. pylori‐induced gastric Shh expression.Grant Funding Source: Supported by NIH 1R01DK083402‐01 (Y. Zavros) and AGA: Funderburg Research Award (Y. Zavros)