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Strong decrease in invasive ability and outer membrane vesicle release in Crohn's disease-associated

Nathalie Rolhion1, Nicolas Barnich, Laurent Claret

  • 1Pathogénie Bactérienne Intestinale, Laboratoire de Bactériologie, Université d'Auvergne, CBRV, 28 Place Henri Dunant, 63001 Clermont-Ferrand, France.

Journal of Bacteriology
|March 19, 2005
PubMed

Insights

Adherent-invasive Escherichia coli uses YfgL protein to release outer membrane vesicles, which are crucial for invading intestinal cells. Deleting yfgL impairs this invasion process in Crohn's disease models.

Area of Science:

  • Microbiology
  • Molecular Biology
  • Cell Biology

Background:

  • Adherent-invasive Escherichia coli (AIEC) strain LF82, isolated from Crohn's disease patients, invades intestinal epithelial cells.
  • Outer membrane vesicles (OMVs) are implicated in bacterial pathogenesis and host-pathogen interactions.

Purpose of the Study:

  • To investigate the role of the yfgL gene and its encoded lipoprotein (YfgL) in AIEC LF82's ability to invade intestinal epithelial cells.
  • To determine the impact of yfgL deletion on the production and release of outer membrane proteins and vesicles.

Main Methods:

  • Genetic manipulation to create yfgL-negative isogenic mutants of AIEC LF82.
  • Invasion assays using Intestine-407 cell cultures.
  • Analysis of outer membrane proteins in culture supernatants using SDS-PAGE and MALDI-TOF MS.
  • Western blot analysis and transmission electron microscopy (TEM) to characterize outer membrane vesicles.

Main Results:

  • Deletion of the yfgL gene significantly reduced the invasion ability of AIEC LF82.
  • The yfgL mutant showed decreased release of outer membrane proteins (OmpA, OmpC) into the supernatant.
  • Characterization confirmed that released proteins were part of outer membrane vesicles, and yfgL deletion decreased OMV release.
  • Complementation with the yfgL gene restored both invasion ability and OMV release.

Conclusions:

  • The YfgL lipoprotein plays a critical role in the biogenesis or release of outer membrane vesicles in AIEC LF82.
  • Reduced OMV release due to yfgL deletion directly correlates with impaired intestinal epithelial cell invasion.
  • Targeting YfgL or OMV production may represent a novel therapeutic strategy against AIEC infections in Crohn's disease.

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