Helicobacter pylori is a Gram-negative bacterium that infects approximately 50% of the global population. H. pylori resides within the stomach in close proximity to gastric epithelial cells, while avoiding direct contact with immune cells. During H. pylori infection, epithelial cells lining the gastric mucosa initiate pro-inflammatory immune responses via the secretion of cytokines and chemokines that function to recruit immune cells to the local tissue. However, the contribution of extracellular vesicles (EVs) released by gastric epithelial cells in driving pathogenesis and promoting pro-inflammatory immune responses to H. pylori infection has not yet been elucidated.
In this study, we aimed to determine the composition and functions of EVs released by gastric epithelial cells in response to H. pylori infection and their contribution to mediating pathogenesis in the host. To examine this, EVs secreted into the cell culture supernatant of gastric epithelial (AGS) cells stimulated with H. pylori, or non-stimulated as controls, were isolated and purified using differential ultracentrifugation and density gradients. The purity, quantity, and type of EVs released by AGS stimulated or control cells were determined using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blot, respectively. Finally, the composition and immunological functions of EVs produced by AGS cells in response to H. pylori infection are currently being examined using proteomic and cell-based immune assays, respectively.
Collectively, our data suggests that gastric epithelial cells secrete increased levels of EVs in response to H. pylori stimulation with altered composition and that these EVs may play a role in cell-to-cell communication and driving pathogenesis. Further investigation into the role of EVs during H. pylori infection will provide novel insights regarding the mechanisms whereby pathogens modulate inflammation at the mucosal epithelial cell surface and will promote the future development of novel interventions to combat H. pylori infections.