Comparison of the Genomic Activity of an EP4-Receptor and b2-Adrenoceptor Agonist in BEAS-2B Human Bronchial Epithelial Cells: In Search of Compartmentalized, cAMP-Dependent Gene ExpressionS

It has been proposed that inhaled E-prostanoid 4 (EP4)-receptor agonists could represent a new class of bronchodilators for the treatment of asthma that are as effective as /32-adrenoceptor agonists. However, the genomic impact of such drugs is unknown despite being potentially deleterious to respiratory health. Herein, we used mRNA-seq to compare the transcriptomic responses produced by 2-[3-[(1R,2S,3R)-3-hydroxy-2-[(E,3S)-3-hydroxy-5[2-(methoxymethyl)phenyl]pent-1-enyl]-5-oxo-cyclopentyl]sulphanylpropylsulphanyl] acetic acid (ONO-AE1-329; an EP4-receptor agonist) and vilanterol (a /32-adrenoceptor agonist) in BEAS-2B human airway epithelial cells. We also determined if an increase in cAMP mediated by different G protein-coupled receptors (GPCRs) promoted distinct transcriptional signatures by expanding this inquiry to include the adenosine A2B- and I-prostanoid receptor agonists, 2-[[6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)phenyl]-2-pyridinyl]thio]-acetamide (Bay60-6583) and taprostene, respectively. Maximally-effective concentrations of ONO-AE1-329 and vilanterol significantly regulated (q 0.05; >= 1.5-/ 0.67-fold) 232 and 320 genes, respectively of which 217 were shared. Spearman analysis showed these gene expression changes to be highly rank order correlated, indicating that the functional overlap between the two interventions should be considerable. Unexpectedly, the genomic effects of ONO-AE1-329, vilanterol, Bay 60-6583, and taprostene were also highly rank order correlated. This finding suggests that cAMP generated by any GPCR would initiate the same transcriptional program. Nevertheless, relative to vilanterol, ONO-AE1-329 typically behaved as a partial agonist that varied across transcripts. These data indicate that each ONOAE1-329-regulated gene differs in sensitivity to cAMP and is defined by a unique receptor occupancy-response relationship. Moreover, if this relatively modest genomic response in BEAS2B cells is retained in vivo, then inhaled EP4-receptor agonists could represent an alternative, and possibly safer, class of bronchodilators.