Helicobacter pylori infection is a major risk factor for the development of gastric cancer. The bacteria reside in close proximity to gastric surface mucous as well as stem and progenitor cells. Here, we take advantage of wild-type and genetically engineered murine gastric organoids and organoid-derived monolayers to study the cellular targets of H. pylori-induced DNA damage and replication stress and to explore possible interactions with preexisting gastric cancer driver mutations. We find using alkaline comet assay, single-molecule DNA fiber assays, and immunofluorescence microscopy of DNA repair foci that H. pylori induces transcription-dependent DNA damage in actively replicating, Leucine-rich-repeat containing G-Protein-Coupled Receptor 5 (Lgr5)-positive antral stem and progenitor cells and their Troy-positive corpus counterparts, but not in other gastric epithelial lineages. Infection-dependent DNA damage is aggravated by Apc inactivation, but not by Trp53 or Smad4 loss, or Erbb2 overexpression. Our data suggest that H. pylori induces DNA damage in stem and progenitor cells, especially in settings of hyperproliferation due to constitutively active Wnt signaling.

• MeSH
• Helicobacter pylori * genetics   MeSH
• Helicobacter Infections * genetics   microbiology   MeSH
• Stem Cells MeSH
• Humans MeSH
• Mice MeSH
• Stomach Neoplasms * pathology   MeSH
• DNA Damage MeSH
• Receptors, G-Protein-Coupled genetics   MeSH
• Genes, Tumor Suppressor MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• adenomatous polyposis coli protein, mouse MeSH Browser
• Receptors, G-Protein-Coupled MeSH

The protective and absorptive functions of the intestinal epithelium rely on differentiated enterocytes in the villi. The differentiation of enterocytes is orchestrated by sub-epithelial mesenchymal cells producing distinct ligands along the villus axis, in particular Bmps and Tgfβ. Here, we show that individual Bmp ligands and Tgfβ drive distinct enterocytic programs specific to villus zonation. Bmp4 is expressed from the centre to the upper part of the villus and activates preferentially genes connected to lipid uptake and metabolism. In contrast, Bmp2 is produced by villus tip mesenchymal cells and it influences the adhesive properties of villus tip epithelial cells and the expression of immunomodulators. Additionally, Tgfβ induces epithelial gene expression programs similar to those triggered by Bmp2. Bmp2-driven villus tip program is activated by a canonical Bmp receptor type I/Smad-dependent mechanism. Finally, we establish an organoid cultivation system that enriches villus tip enterocytes and thereby better mimics the cellular composition of the intestinal epithelium. Our data suggest that not only a Bmp gradient but also the activity of individual Bmp drives specific enterocytic programs.

• Keywords
• Tgfβ / Bmp signalling, enterocytes, epithelial differentiation, intestinal mesenchymal cells, small intestine,
• MeSH
• Cell Differentiation MeSH
• Enterocytes * metabolism   MeSH
• Bone Morphogenetic Proteins metabolism   MeSH
• Ligands MeSH
• Intestinal Mucosa * metabolism   MeSH
• Transforming Growth Factor beta metabolism   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Bone Morphogenetic Proteins MeSH
• Ligands MeSH
• Transforming Growth Factor beta MeSH