Interleukin-1 beta Differentially Regulates beta sub(2) Adrenoreceptor and Prostaglandin E sub(2)-mediated cAMP Accumulation and Chloride Efflux from Calu-3 Bronchial Epithelial Cells: Role of receptor changes, adenylyl cyclase, cyclo-oxygenase 2, and protein kinase A

Here we tested the effect of interleukin-1 beta , a pro-inflammatory cytokine, on cAMP accumulation and chloride efflux in Calu-3 airway epithelial cells in response to ligands binding to adenylyl cyclase-coupled receptors such as the beta sub(2) adrenoreceptor and EP prostanoid receptors. Interleukin-1 beta significantly increased isoprenaline-induced cAMP accumulation by increasing beta sub(2) adrenoreceptor numbers via a protein kinase A-dependent mechanism. In contrast, interleukin-1 beta significantly impaired prostaglandin E sub(2)-induced cAMP accumulation by induction of cyclo-oxygenase-2, prostaglandin E sub(2) production, and a resulting down-regulation of adenylyl cyclase. The cAMP changes were all mirrored by alterations in chloride efflux assessed using the fluorescent chloride probe N-(ethoxycarbonylmethyl)-6-methoxyquinolinium bromide with interleukin-1 beta increasing chloride efflux in response to isoprenaline and reducing the response to prostaglandin E sub(2). Studies with glibenclamide confirmed that chloride efflux was via the cystic fibrosis transmembrane conductance regulator. Calu-3 expresses EP sub(4) receptors, but not EP sub(2), and receptor expression is reduced by interleukin-1 beta . Collectively, these results provide mechanistic insight into how interleukin-1 beta can differentially regulate cAMP generation and chloride efflux in response to different adenylyl cyclase-coupled ligands in the same cell. These findings have important implications for diseases involving inflammation and abnormal ion flux such as cystic fibrosis.