The bile salt sodium taurocholate induces Campylobacter jejuni outer membrane vesicle production and increases OMV ‐associated proteolytic activity.

In this study, the effect of ST on C. jejuni OMVs was investigated. Physiological concentrations of ST do not have an inhibitory effect on C. jejuni growth until the early stationary phase. Co‐culture of C. jejuni with 0.1% or 0.2% (w/v) ST stimulates OMV production, increasing both lipid and protein concentrations. C. jejuni ST‐OMVs possess increased proteolytic activity and exhibit a different protein profile compared to OMVs isolated in the absence of ST. ST‐OMVs exhibit enhanced cytotoxicity and immunogenicity to T84 IECs and enhanced killing of Galleria mellonella larvae. ST increases the level of mRNA transcripts of the OMVs‐associated serine protease genes and the cdtABC operon that encodes the cytolethal distending toxin. Co‐culture with ST significantly enhances the OMVs‐induced cleavage of E‐cadherin and occludin. C. jejuni OMVs also cleave the major endoplasmic reticulum (ER) chaperone protein BiP/GRP78 and this activity is associated with the Cj1365c protease. This data suggests that C. jejuni responds to the presence of physiological concentrations of the bile salt ST which increases OMV production and the synthesis of virulence‐associated factors that are secreted within the OMVs. We propose that these events contribute to pathogenesis.

Source: Cellular Microbiology - December 4, 2017 Category: Microbiology Authors: Abdi Elmi, Amber Dorey, Eleanor Watson, Heena Jagatia, Neil F. Inglis, Ozan Gundogdu, Mona Bajaj ‐Elliott, Brendan W. Wren, David G.E. Smith, Nick Dorrell Tags: RESEARCH ARTICLE Source Type: research