W101 - Omeprazole Downregulates Inflammatory Cytokines and Eosinophil Activation Markers in the Co-culture of Eosinophil and Esophageal Epithelial Cells
Abstract Text: Eosinophilic esophagitis (EoE) is a chronic allergic disease, characterized by esophageal dysfunction, type-2 cell-mediated inflammation, and esophageal epithelial eosinophilic infiltrate. Proton pump inhibitors (PPIs) are used as first-line EoE therapy however bidirectional communication between eosinophils and epithelial cells and the role of PPIs in the milieu is yet to be understood. Here we use monolayer or co-cultures to understand the mechanism of action of omeprazole. Human esophageal epithelial cells were grown in a monolayer and treated with 100 ng/ml of IL-13 and/or 50 µM acid-activated omeprazole for 24 h. Culture supernatant was collected for cytokine analysis, and cells were lysed to screen STAT 6 level. For co-culture, eosinophils isolated were added to the EPC2 cells monolayer in a 1:1 mixture of RPMI with 10% FBS and keratinocyte serum-free media. Cytokines were measured in culture supernatant and activation markers in cells by flow cytometry. IL-13 treatment significantly increased the phospho-STAT6, eotaxin-3, and IP-10 levels in monolayer which was downregulated by omeprazole. Similarly, in co-culture, eotaxin-3, IP-10, and MIP-1 beta were elevated in presence of IL-13 and omeprazole reduced the level back to normal. Eosinophils had 76% and 73% cell viability in coculture after 24h and 48h respectively whereas the viability was as low as 38% and 18.5% in eosinophil-only culture. Co-culture with EPC2 activated eosinophils with higher CD69 and siglec8 which was downregulated by omeprazole. In conclusion, omeprazole attenuates the EoE-associated inflammation by downregulating the inflammatory cytokines and eosinophil activation markers in the co-culture of eosinophils and esophageal epithelial cells.
