P009 Autophagy-related host factors are implicated in the incapability of macrophages from Crohn's disease patients to mediate adherent-invasive E. coli clearance. (16th January 2018)

• Record Type: Journal Article
• Authors: Douadi, C; Buisson, A; Ouchchane, L; Goutte, M; Hugot, J -P; Dubois, A; Minet-Quinard, R; Bouvier, D; Bommelaer, G; Vazeille, E; Barnich, N
• Is Part Of: Journal of Crohn's and colitis. Volume 12:Number 1(2018:Jan.)Supplement 1
• Page Start: S096
• Page End: S096
• Publication Date: 2018-01-16
• Subjects: Inflammatory bowel diseases -- Periodicals; 616.344005
• DOI: 10.1093/ecco-jcc/jjx180.136
• Languages: English
• ISSNs: 1873-9946

Abstract

Abstract: Background: Several experimental data have highlighted the potential role of intestinal macrophages in the pathogenesis of Crohn's disease (CD). These macrophages present a defect in the control of CD-associated adherent-invasive E. coli (AIEC) replication, which could be linked to altered autophagy. We investigated the impact of several CD-associated singer nucleotide polymorphisms (SNPs) including those implicated in autophagy on the ability of macrophages from CD patients to mediate AIEC bacterial clearance. Methods: Peripheral blood monocyte-derived macrophages (MDM) were obtained from 95 CD patients, 30 ulcerative colitis (UC) patients and 15 healthy subjects genotyped for CD-associated SNPs-related to autophagy, especially IRGM (rs10065172) and ULK1 (rs12303764) and, infected with AIEC LF82 reference strain. Functional assay were performed on MDM after AIEC infection and/or after a short-term silencing of ULK1 gene. The numbers of intracellular bacteria were determined using gentamicin protection assay. IRGM, ULK1 and p62 protein expression was determined by western blot. Results: AIEC survival was increased within MDM from CD patients compared with those from UC patients or healthy subjects ( p = 0.0019). MDM from CD patients failed to mediate AIEC bacterial clearance especially in patients harbouring the CD-associated IRGM SNP ( p = 0.045). In contrast, AIEC survival was decreased in MDM from patients with the CD-associated ULK1 SNP ( p = 0.046). Expression of ULK1, but not IRGM and p62, was increased in MDM from CD patients infected by AIEC bacteria compared with MDM from UC patients or healthy subjects ( p = 0.0056) and are significantly correlated with the AIEC survival ( p = 0.0369). In the same way, the down-regulation of ULK1 within MDM limits the AIEC survival ( p = 0.0018) within MDM and could regulate the autophagic flux suggested by an increase of the expression of p62 ( p = 0.0043). Conclusions: We confirmed that MDM from CD patients failed to mediate AIEC bacterial clearance compared with those of UC or healthy subjects. Our results highlight a role of CD-associated SNPs, related to autophagy, IRGM and ULK1, on the ability of macrophages from CD patients to mediate AIEC bacterial clearance. At the protein level, our data suggested a potential role of the protein ULK1, the cornerstone of autophagy initiation, to control AIEC bacteria in patients with CD. This protein could be a potential target to alter the interaction between macrophages and AIEC in patients with CD.