Helicobacter pylori-Induced Disruption of Monolayer Permeability and Proinflammatory Cytokine Secretion in Polarized Human Gastric

Helicobacter pylori infection of the stomach is related to the development of diverse gastric pathologies. The ability ofH. pylori to compromise epithelial junctional complexes and to induce proinflammatory cytokines is believed to contribute to pathogene-sis. The purpose of this study was to use an in vitro human gastric epithelial model to investigate the ability ofH. pylori to affect permeability and the extent and polarity of the host inflammatory response. NCI-N87monolayers were cocultured with live or heat-killedH. pylori or culture supernatants. Epithelial barrier function was measured by transepithelial electric resistance (TEER) analysis, diffusion of fluorescein isothiocyanate (FITC)-labeled markers, and immunostaining for tight junction pro-teins. Supernatants from both apical and basolateral chambers were tested for cytokine production by multiplex analysis.H. pylori caused a significant decrease in TEER, an increased passage of markers through the infected monolayer, and severe disrup-tion and mislocalization of ZO-1 and claudin-1 proteins. Cell viability was not altered byH. pylori, indicating that loss of barrier function could be attributed to a breakdown of tight junction integrity. Significantly high levels of cytokine secretion were in-duced by either viable or heat-killedH. pylori.H. pylori affects monolayer permeability of polarized human gastric epithelial cells. Proinflammatory cytokines were secreted in a polarized manner, mostly basolaterally. Live bacteria are required for dis-ruption of tight junctions but not for the induction of cytokine secretion. The NCI-N87 cell line provides an excellent model for the in vitro study ofH. pylori pathogenesis and the epithelial cell host response to infection. Gastric epithelial barrier function is essential for preventingpotentially dangerous organisms present in the lumen fro