P106 Role of Adenylate Cyclase Pathway in Prevention of Pulmonary Fibrosis

Our previous studies have shown that blocking Ca2+-signaling reduces TGFβ-mediated extracellular matrix (ECM) deposition and progression of bleomycin-mediated fibrosis. As such, disruption of Ca2+-wave activity may prove useful in the treatment of pulmonary fibrosis. Prostaglandin E2 (PGE2) is known to exhibit certain anti-fibrotic effects. However, its effect on Ca2+-wave activity is unknown. In this study, we examined the role of PGE2 in regulating Ca2+ signaling in normal and diseased (IPF) fibroblasts. Human pulmonary fibroblasts (normal and IPF) were cultured and stimulated with either TGFβ or vehicle in the presence of various blockers. Ca2+ waves were monitored by confocal [Ca2+]i fluorimetry. RT-PCR and western blot were used to measure gene expression and different protein levels. We found that 500 nM PGE2 eliminated TGFβ-induced Ca2+ wave activity in normal fibroblasts and spontaneous Ca2+ wave activity in IPF fibroblasts. This inhibitory effect was mimicked by forskolin. We also found that PGE2 dramatically reduced the expression of ECM genes both in TGFβ-treated normal fibroblasts and in IPF fibroblasts. Immunofluorescence study showed that PGE2 inhibited the progression of fibroblast to myofibroblast transformation. We also examined the role of PGE2 in TGFβ-mediated other pathways.