TY - JOUR T1 - Sphingosine-1-phosphate receptor expression and signalling in human airway smooth muscle cells JF - European Respiratory Journal JO - Eur Respir J VL - 38 IS - Suppl 55 SP - p750 AU - Elisabeth Stafflinger AU - Holly Foster AU - Katharina Mahn AU - Christopher Corrigan AU - Tak Lee AU - Grzegorz Woszczek Y1 - 2011/09/01 UR - http://erj.ersjournals.com/content/38/Suppl_55/p750.abstract N2 - Sphingosine-1-phosphate (S1P), a bioactive lipid and ligand for five G protein coupled receptors (S1P1-S1P5), is a key regulator of cell trafficking, cell differentiation and immune responses. Recently, increased concentrations of S1P have been detected in airways of asthmatic subjects and S1P has been shown to be a potent constrictor of human airway smooth muscle (HASM) cells. The aim of this study was to investigate the expression and signalling pathways of S1P receptors in HASM cells. HASMs have been grown from bronchial biopsies of healthy individuals. Real-time PCR has been used to determine gene expression. Intracellular signalling in response to S1P was measured using MAP kinase phosphorylation, intracellular calcium and cAMP assays. Three of the five known receptors are expressed in HASM cells at mRNA level: S1P1, S1P2, and S1P3. S1P potently activated intracellular calcium flux in a concentration-dependent manner, with EC50=4×10-9M. Using a range of selective agonists and antagonists, S1P1 and S1P3 were found to couple to Gi and inhibit forskolin induced cAMP generation, whereas S1P2 and S1P3 signalled through intracellular calcium mobilisation. S1P also induced phosphorylation of extracellular signal-regulated kinase (Erk) and increased expression of several genes, including interleukin-6. This study demonstrates that S1P receptors may signal effectively through multiple intracellular pathways in response to S1P and activate HASM cells. ER -