P051 IFNγ-macrophages could mediate EMT in Crohn’s disease through the WNT pathway
Edo, M.M.(1);Macias-Ceja, D.C.(2);Bauset, C.(2);Lis-Lopez, L.(2);Coll, S.(2);Seco-Cervera, M.(3);Cosin-Roger, J.(3);Calatayud, S.(2);Barrachina, M.D.(2);Ortiz-Masiá, D.(1);
(1)Universitat de Valencia, Medicine, Valencia, Spain;(2)Universitat de Valencia, Pharmacology, Valencia, Spain;(3)FISABIO, Pharmacology, Valencia, Spain;
Background
Macrophages contribute to fibrosis by releasing different mediators and the pattern of secretion may vary depending on the surrounding environment. We previously described that the mRNA expression of IFNγ was significantly higher in intestinal samples from CD patients.
Methods
The aim of the present study is to analyze the role of IFNγ-treated macrophages in epithelial mesenchymal transition (EMT) through the WNT pathway. The mRNA and protein expression of IFNγ in surgical resections from Crohn´s disease. U937 were differentiated to macrophages and then treated with IFNγ (10 ng/ml) for 4 days, the mRNA expression of WNT2b, WNT6 and TGFβ were determined by RT-PCR and protein. IFNγ-U937 were coculture with HT29 cells for 3 days and the expression of EMT markers, βCATENIN and WNT2b in HT29 cells were analyzed by WB. In some cases, HT29 cells were treated with the inhibitor of the WNT-pathway, XAV939 (1 μM), or were transfected with vectors-targeting human FZD4 (miFzd4).
Results
Results are expressed as mean±SEM. Statistical analysis was performed by ANOVA + Newman-Keuls or unpaired t-test.The mRNA and protein expression of IFNγ were significantly higher in intestinal samples from B2 CD patients (11.4±1.6 fold induction and 70,0 ± 2,3 pg/mg, respectively) and B3 CD patients (14.2±1.8 fold induction and 80,4 ± 6,8 pg/mg, respectively) than in controls (1,0±0,1 fold induction and 18,9 ± 0,3 pg/mg, respectively). U937 cells treated with IFNγ increased significantly the protein expression of WNT2b (1,3 ± 0,07 N=13* vs vehicle) but not the expression of WNT6 or TGFβ. IFNγ-U937 co-cultured with HT29 increased significantly the protein expression of EMT markers, βCATENIN and WNT2b in HT29 cells (VIMENTIN: 2,7 ± 0,3 N=6* vs vehicle-HT29; SNAIL1: 1,5 ± 0,1 N=5* vs vehicle-HT29; βCATENIN: 1,4 ± 0,09 N=5* vs vehicle-HT29; WNT2b: 2,0 ± 0,3 N=8* vs vehicle-HT29). Treatment HT29 cells with XAV939 (VIMENTIN: 1,4 ± 0,4 N=6 vs vehicle-HT29 XAV; SNAIL1: 1,0 ± 0,1 N=5 vs vehicle-HT29 XAV; βCATENIN: 0,8 ± 0,1 N=5 vs vehicle-HT29 XAV) or with miFzd4 (VIMENTIN: 0,3 ± 0,07 N=12* vs IFNγ-HT29 mock; SNAIL1: 0,5 ± 0,06 N=12* vs IFNγ-HT29 mock; βCATENIN: 0,6 ± 0,04 N=12* vs IFNγ-HT29 mock; FZD4: 0,5 ± 0,04 N=12* vs IFNγ-HT29 mock) partially reversed the increases produced by IFNγ-U937 in HT29 cells.
Conclusion
IFNγ-macrophages may stimulate the expression of WNT ligands in an autocrine and paracrine manner. The expression of WNT ligands at the epithelial level could favor mesenchymal epithelial transition through WNT2b ligand and FZD4 receptor.