Helicobacter pylori outer membrane vesicle proteome

Gram negative bacteria release outer membrane vesicles (OMVs) as part of their natural growth. These OMVs take part in a biological functions including bacterial communication, exchange of genetic material and bacterial pathogenesis. However, the relationship between bacterial growth stage and OMV protein composition has not been explored before nor how their proteome is different to their parent bacterium. In this study, we examined the proteome of Helicobacter pylori and its OMVs from early log, late log or stationary phase of growth and found that globally, the protein content of OMVs over time is vastly different to one another as well as to their parent bacterium. OMVs purified from early log phase of growth contained the greatest number of unique proteins and a significant upregulation of virulence and pathogenic proteins. However, when compared back to their parent bacterium, OMVs from later stages of growth contained more unique proteins than those from earlier stages of growth. We show for the first time the regulation of OMV protein composition by H. pylori that is dependent on bacterial growth stage. Our results have expanded our understanding of the fundamental production of OMVs and the selective packaging of cargo in OMVs that result in specific functions.