Effect of MP‐AzeFlu compared to monotherapy on COX‐2, PGE(2), and EP2 gene expression in upper airway mucosa

MP‐AzeFlu (intranasal fluticasone and azelastine) has been widely studied and has demonstrated efficacy in Allergic rhinitis with a superior effect compared to these drugs administered individually; however, the mechanism by which MP‐AzeFlu produces this improved clinical effect has not yet been fully explained. In this study, we investigated the effect of MP‐AzeFlu and fluticasone propionate (FP) on arachidonic acid metabolism as measured by changes in regulation of cyclooxygenase (COX) isoforms, prostaglandin (PG) D(2), PGE(2), PGE(2) receptor (EP) 2, and EP3. Expression of these key inflammation markers was assessed through an in vitro model of upper airway inflammation using fibroblasts derived from both healthy and inflamed upper airway mucosa. Both MP‐AzeFlu and FP inhibited interleukin‐1β‐induced COX‐2 messenger RNA (mRNA) and protein expression and PGE(2) secretion in vitro. MP‐AzeFlu and FP both upregulated EP2 mRNA expression, though neither upregulated EP2 protein expression. This downregulation of COX‐2 and PGE(2) coupled with upregulation of EP2 receptor expression reinforces the anti‐inflammatory effect of MP‐AzeFlu in upper airway inflammation.