The Vat-AIEC protease promotes crossing of the intestinal mucus layer by Crohn’s disease-associated Escherichia coli Article - Mai 2016

Lucie Gibold, Estelle Garénaux, Guillaume Dalmasso, Camille Gallucci, David Cia, Benoit Mottet-Auselo, Tiphanie Faïs, Arlette Darfeuille-Michaud, Hang Thi Thu Nguyen, Nicolas Barnich, Richard Bonnet, Julien Delmas

Lucie Gibold, Estelle Garénaux, Guillaume Dalmasso, Camille Gallucci, David Cia, Benoit Mottet-Auselo, Tiphanie Faïs, Arlette Darfeuille-Michaud, Hang Thi Thu Nguyen, Nicolas Barnich, Richard Bonnet, Julien Delmas, « The Vat-AIEC protease promotes crossing of the intestinal mucus layer by Crohn’s disease-associated Escherichia coli  », Cellular Microbiology, mai 2016, pp. 617 - 631. ISSN 1462-5814

Abstract

The aetiology of Crohn’s disease (CD) involves disorders in host genetic factors and intestinal microbiota. Adherent-invasive Escherichia coli (AIEC) are receiving increased attention because in studies of mucosa-associated microbiota, they are more prevalent in CD patients than in healthy subjects. AIEC are associated both with ileal and colonic disease phenotypes. In this study, we reported a protease called Vat-AIEC from AIEC that favours the mucosa colonization. The deletion of the Vat-AIEC-encoding gene resulted in an adhesion-impaired phenotype in vitro and affected the colonization of bacteria in contact with intestinal epithelial cells in a murine intestinal loop model, and also their gut colonization in vivo. Furthermore, unlike LF82vat-AIEC, wild-type AIEC reference strain LF82 was able to penetrate a mucus column extensively and promoted the degradation of mucins and a decrease in mucus viscosity. Vat-AIEC transcription was stimulated by several chemical conditions found in the ileum environment. Finally, the screening of E.coli strains isolated from CD patients revealed a preferential vat-AIEC association with AIEC strains belonging to the B2 phylogroup. Overall, this study revealed a new component of AIEC virulence that might favour their implantation in the gut of CD patients.

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