Crohn disease-associated Escherichia coli promote gastrointestinal inflammatory disorders by activation of HIF-dependent responses

S Mimouna, D Gonçalves, N Barnich… - Gut …, 2011 - Taylor & Francis
S Mimouna, D Gonçalves, N Barnich, A Darfeuille-Michaud, P Hofman, V Vouret-Craviari
Gut microbes, 2011Taylor & Francis
Crohn disease (CD) ileal lesions are colonized by adherent-invasive E. coli (AIEC) that
locally induce inflammation. Hypoxia inducible factor (HIF)-1alpha protein is expressed in
acute and chronically inflamed site; however the molecular basis of this expression is not
fully understood. The aim of the study was to access whether AIEC induce HIF-1α
expression and to study the consequence of HIF-1α expression on the onset of Crohn
disease pathogenesis. We show that HIF-1α is maximally expressed in inflamed ileal …
Crohn disease (CD) ileal lesions are colonized by adherent-invasive E. coli (AIEC) that locally induce inflammation. Hypoxia inducible factor (HIF)-1alpha protein is expressed in acute and chronically inflamed site; however the molecular basis of this expression is not fully understood. The aim of the study was to access whether AIEC induce HIF-1α expression and to study the consequence of HIF-1α expression on the onset of Crohn disease pathogenesis. We show that HIF-1α is maximally expressed in inflamed ileal epithelium of CD-patients. CEACAM6, a protein that acts as a receptor of AIEC, is expressed in this particular condition. Using CEABAC 10 transgenic mice that express CEACAM6, we show that AIEC bacteria, but not non-pathogenic E. coli K12, induce the production of HIF-1alpha protein and the activation of VEGF/VEGFR signaling. Downstream analyses on human intestinal epithelial cells silenced for hif-1α, highlight the crucial role of this protein in production of pro-angiogenic factors. This study highlights the crucial role of AIEC bacteria as promoter of inflammatory disorders of the gastrointestinal tract and provides clear evidence that HIF-1α protein plays a major role in mediating this effect.
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