Increased Outer Membrane Vesicle Formation in a Helicobacter pylori tolB Mutant. Issue 4 (9th February 2015)

• Record Type: Journal Article
• Authors: Turner, Lorinda; Praszkier, Judyta; Hutton, Melanie L.; Steer, David; Ramm, Georg; Kaparakis‐Liaskos, Maria; Ferrero, Richard L.
• Is Part Of: Helicobacter. Volume 20:Issue 4(2015:Aug.)
• Page Start: 269
• Page End: 283
• Publication Date: 2015-02-09
• Subjects: Helicobacter -- Periodicals; Helicobacter infections -- Periodicals; Stomach -- Diseases -- Periodicals; 616.3301405
• DOI: 10.1111/hel.12196
• Languages: English
• ISSNs: 1083-4389

Abstract

<abstract abstract-type="main" id="hel12196-abs-0001"> <title>Abstract</title> <sec id="hel12196-sec-0001" sec-type="section"> <title>Background</title> <p>Multiple studies have established the importance of the <italic>tol‐pal</italic> gene cluster in bacterial cell membrane integrity and outer membrane vesicle (OMV) formation in <italic>Escherichia coli</italic>. In contrast, the functions of Tol‐Pal proteins in pathogenic organisms, including those of the <italic>Epsilonproteobacteria</italic>, remain poorly if at all defined. The aim of this study was to characterize the roles of two key components of the Tol‐Pal system, TolB and Pal, in OMV formation in the pathogenic bacterium, <italic>Helicobacter pylori</italic>.</p> </sec> <sec id="hel12196-sec-0002" sec-type="section"> <title>Methods</title> <p> <italic>H. pylori</italic> Δ<italic>tolB</italic>, Δ<italic>pal</italic> and Δ<italic>tolBpal</italic> mutants, as well as complemented strains, were generated and assessed for changes in morphology and OMV production by scanning electron microscopy and enzyme‐linked immunoassay (ELISA), respectively. The protein content and pro‐inflammatory properties of OMVs were determined by mass spectroscopy and interleukin‐8 (IL‐8) ELISA on culture supernatants from OMV‐stimulated cells, respectively.</p> </sec> <sec id="hel12196-sec-0003" sec-type="section"> <title>Results</title> <p> <italic>H. pylori</italic> Δ<italic>tolB</italic> and Δ<italic>pal</italic> bacteria exhibited aberrant cell morphology and/or flagella biosynthesis. Importantly, the disruption of <italic>H. pylori tolB</italic> but not <italic>pal</italic> resulted in a significant increase in OMV production. The OMVs from <italic>H. pylori</italic> Δ<italic>tolB</italic> and Δ<italic>pal</italic> bacteria harbored many of the major outer membrane and virulence proteins observed in wild‐type (WT) OMVs. Interestingly, Δ<italic>tolB</italic>, Δ<italic>pal</italic> and Δ<italic>tolBpal</italic> OMVs induced significantly higher levels of IL‐8 production by host cells, compared with WT OMVs.</p> </sec> <sec id="hel12196-sec-0004" sec-type="section"> <title>Conclusions</title> <p>This work demonstrates that TolB and Pal are important for membrane integrity in <italic>H. pylori</italic>. Moreover, it shows how <italic>H. pylori tolB</italic>‐<italic>pal</italic> genes may be manipulated to develop "hypervesiculating" strains for vaccine purposes.</p> </sec> </abstract>