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P089 IFNγ-macrophages could mediate EMT in Crohn’s disease

Marín-Aracil, J.(1);Barrachina , M.D.(1);Bauset, C.(1);Cosin-Roger, J.(2);Coll, S.(1);Calatayud, S.(1);Antonio, L.S.(3);Ortiz-Masiá, D.(1);

(1)Universitat de Valencia, Facultad de Medicina, Valencia, Spain;(2)Hospital Doctor Peset, Fisabio, Valencia, Spain;(3)Hospital Doctor Peset, Servicio Digestivo, 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. The aim of the present study is to analyze the role of IFNγ-treated macrophages in epithelial mesenchymal transition (EMT).

Methods

The mRNA and protein expression of IFN in surgical resections from Crohn´s disease. U937 were differentiated to macrophages and then treated with IFNγ (2 ng/ml) for 4 days, the mRNA expression of macrophages markers were determined by RT-PCR. IFNγ-U937 were coculture with HT29 cells for 2 days and the expression of EMT markers in HT29 cells were analyzed by RT-PCR and WB. Results are expressed as mean±SEM (n≥5). Statistical analysis was performed by ANOVA + Newman-Keuls.

Results

The mRNA and protein expression of IFNγ  were significantly higher in intestinal samples from B2 CD patients (11.4±1.6 fold induction and 3.5±0.3 pg/mg, respectively) and B3 CD patients (14.2±1.8 fold induction and 3.1±0.1 pg/mg, respectively) than in controls (1,0±0,1 fold induction and 0.8±0,1 pg/mg, respectively). U937 cells treated with IFNγ increased significantly the mRNA expression of CD16 (1.9±0.2* vs vehicle) and CD86 (1.6±0.1* vs vehicle). IFNγ-U937 cocultured with HT29 increased significantly the mRNA and protein expression of EMT markers in HT29 cells (Vimentin: 3.0±0.5* vs vehicle-HT29; αSMA: 24.4±8.3* vs vehicle-HT29; SNAIL1: 2.7±0.5* vs vehicle-HT29) respect IFNγ-HT29 cells (Vimentin: 0.6±0.01 vs vehicle-HT29; αSMA: 1.1±0.4 vs vehicle-HT29; SNAIL1: 0.7±0.06 vs vehicle-HT29).

Conclusion

IFNγ could be responsible for the increase in the number of CD86/CD16 macrophages in CD patients. A macrophage phenotype expressing CD86/CD16 may act as a source of EMT mediators in intestinal tissue from CD patients.

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