Anti-TNF Agents Restrict Adherent-invasive Escherichia coli Replication Within Macrophages Through Modulation of Chitinase 3-like 1 in Patients with Crohn's Disease.

BACKGROUND AND AIMS: The mechanism of action of anti-tumour necrosis factor [anti-TNF] agents could implicate macrophage modulation in Crohn's disease [CD]. As CD macrophages are defective in controlling CD-associated adherent-invasive Escherichia coli [AIEC], anti-TNF agents could limit AIEC replication within macrophages. We assessed the effect of anti-TNF agents on AIEC survival within monocyte-derived macrophages [MDMs] from CD patients and attempted to identify the proteins involved. METHODS: Peripheral blood MDMs were obtained from 44 CD patients [22 with and 22 without anti-TNF agents]. MDMs were infected with reference strain AIEC-LF82. Proteomic analysis was performed before and 6 h after AIEC-LF82 infection. RESULTS: AIEC-LF82 survival was lower in MDMs from CD patients receiving anti-TNF agents compared to those who did not [-73%, p = 0.006]. After AIEC-LF82 infection, the levels of CD82 [p = 0.007], ILF3 [Interleukin enhancer-binding factor 3; p = 0.001], FLOT-1 [Flotillin-1; p = 0.007] and CHI3L1 [Chitinase 3-like 1; p = 0.035] proteins were different within CD-MDMs depending on anti-TNF exposure. FLOT-1 [ϱ = -0.44; p = 0.038] and CHI3L1 [ϱ = 0.57, p = 0.006] levels were inversely and positively correlated with AIEC survival within MDMs from CD patients with or without anti-TNF, respectively. We observed a dose-dependent decrease of AIEC-LF82 survival after adjunction of anti-TNF within MDMs, inducing an increase of FLOT-1 and decrease of CHI3L1 mRNA levels. Neutralization of intra-macrophagic CHI3L1 protein using anti-CHI3L1 antibodies reduced AIEC survival within macrophages 6 h after infection [p < 0.05]. CONCLUSION: Anti-TNF agents are able to restrict replication of pathobionts, such as AIEC, within macrophages by modulating FLOT-1 and CHI3L1 expression in CD patients.

Macrophages Inability to Mediate Adherent-Invasive E. coli Replication is Linked to Autophagy in Crohn's Disease Patients.

The macrophages from Crohn's Disease (CD) patients are defective to control the replication of CD-associated adherent-invasive E. coli (AIEC). We aimed to identify the host factors associated with AIEC replication focusing on polymorphisms related to autophagy. Peripheral blood monocyte-derived macrophages (MDM), obtained from 95 CD patient, 30 ulcerative colitis (UC) patients and 15 healthy subjects, were genotyped for several CD-associated polymorphisms. AIEC bacteria survival increased within MDM from CD patients compared to UC (p = 0.0019). AIEC bacteria survival increased in patients with CD-associated polymorphism IRGM (p = 0.05) and reduced in those with CD-associated polymorphisms XBP-1 (p = 0.026) and ULK-1 (p = 0.033). AIEC infection led to an increase of pro-inflammatory cytokines IL-1ß (p < 0.0001) and TNF-α (p < 0.0001) in CD macrophages. ULK-1 expression increased in AIEC-infected MDM from CD patients compared to MDM from UC patients or healthy subjects (p = 0.0056) and correlated with AIEC survival (p = 0.0013). Moreover, the expression of ULK-1 phosphorylation on Serine 757 decreased following to AIEC infection (p < 0.0001). Short-term silencing of ULK-1 and IRGM genes restricted and promote, respectively, AIEC survival within MDM (p = 0.0018 and p = 0.0291). In conclusion, the macrophage defect to mediate AIEC clearance in CD patients is linked to polymorphisms related to autophagy such as IRGM and ULK-1.