Helicobacter pyloritargets cancer-associated apical-junctional constituents in gastroids and gastric epithelial cells

Abstract

Objective Helicobacter pylori strains that express the oncoprotein CagA augment risk for gastric cancer. However, the precise mechanisms through which cag+ strains heighten cancer risk have not been fully delineated and model systems that recapitulate the gastric niche are critical for understanding pathogenesis. Gastroids are three-dimensional organ-like structures that provide unique opportunities to study host-H. pylori interactions in a preclinical model. We used gastroids to inform and direct in vitro studies to define mechanisms through which H. pylori modulates expression of the cancer-associated tight junction protein claudin-7. Design Gastroids were infected by luminal microinjection, and MKN28 gastric epithelial cells were cocultured with H. pylori wild-type cag+ strains or isogenic mutants. β-catenin, claudin-7 and snail localisation was determined by immunocytochemistry. Proliferation was assessed using 5-ethynyl-2′-deoxyuridine, and levels of claudin-7 and snail were determined by western blot and flow cytometry. Results Gastroids developed into a self-organising differentiation axis and H. pylori induced mislocalisation of claudin-7 and increased proliferation in a CagA- and β-catenin-dependent manner. In MKN28 cells, H pylori-induced suppression of claudin-7 was regulated by β-catenin and snail. Similarly, snail expression was increased and claudin-7 levels were decreased among H. pylori-infected individuals. Conclusions H. pylori increase proliferation in a strain-specific manner in a novel gastroid system. H. pylori also alter expression and localisation of claudin-7 in gastroids and human epithelial cells, which is mediated by β-catenin and snail activation. These data provide new insights into molecular interactions with carcinogenic potential that occur between H. pylori and epithelial cells within the gastric niche.

Claudins and cancer: Fall of the soldiers entrusted to protect the gate and keep the barrier intact

“…Gene manipulation studies have further highlighted a critical role of claudin-7 in maintaining the epithelial integrity in the mucosal epithelium as loss of claudin-7 results in inflammation and neonatal death [54,55]. Of interest, loss of claudin-7 expression was also recently associated with H. pylori-associated gastric cancer [56]. Thus, considering that the changes in claudin expression can modulate epithelial and immune homeostasis, the effect of the changes in claudin expression may be influenced by the tissue environment and context of the disease.…”

Organoid Models of Human Gastrointestinal Development and Disease

“…A separate study that found activation of NF-κB following injection of H pylori into mouse gastric epithelial organoids; 84 it reported upregulation of Sonic hedgehog, a protein involved in vertebrate development and the immune response to H pylori 84 . In a similar study, Wroblewski et al showed that H pylori infection of mouse gastric epithelial organoids resulted in mislocalization of occludin at the tight junction, previously observed in vivo 138, 139 . Similar to findings from PSC-derived gastric organoids, this study demonstrated that only H pylori variants that expressed CagA increased proliferation in gastric organoids 138 .…”

“…In a similar study, Wroblewski et al showed that H pylori infection of mouse gastric epithelial organoids resulted in mislocalization of occludin at the tight junction, previously observed in vivo 138, 139 . Similar to findings from PSC-derived gastric organoids, this study demonstrated that only H pylori variants that expressed CagA increased proliferation in gastric organoids 138 . Together, these studies have shown that H pylori infection can be modeled gastric organoids and can be used to study gastric transformation.…”

Role ofHelicobacter pyloriinfection in pathogenesis of gastric carcinoma

“…As reported, CagA translocation is rele vant to mislocalization of ZO1 in epithelial cells [47,48] . Studies revealed that H. pylori altered expression and localisation of claudin7, a cancerassociated tight junction protein, in gastroids and human epithelial cells, which was mediated by βcatenin and snail activation [49] . A recent study demonstrated that H. pylori diminished acidinduced tightening of cell junctions, affected the response of epithelial cells to acid, which took effects in inflammatory response and alteration of the barrier function [50] .…”