elafin and sphingosine-1-phosphate

Sphingosine 1-phosphate (S1P), an important inflammatory mediator, has been shown to regulate COX-2 production and promote various cellular responses such as cell migration. Mevastatin, an inhibitor of 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-CoA), effectively inhibits inflammatory responses. However, the mechanisms underlying S1P-evoked COX-2-dependent cell migration, which is modulated by mevastatin in human tracheal smooth muscle cells (HTSMCs) remain unclear.. The expression of COX-2 was determined by Western blotting, real time-PCR and promoter analyses. The signalling molecules were investigated by pretreatment with respective pharmacological inhibitors or transfection with siRNAs. The interaction between COX-2 promoter and transcription factors was determined by chromatin immunoprecipitation assay. Finally, the effect of mevastatin on HTSMC migration and leukocyte counts in BAL fluid and COX-2 expression induced by S1P was determined by a cell migration assay, cell counting and Western blot.. S1P stimulated mTOR activation through the Nox2/ROS and PI3K/Akt pathways, which can further stimulate FoxO1 phosphorylation and translocation to the cytosol. We also found that S1P induced CREB activation and translocation via an mTOR-independent signalling pathway. Finally, we showed that pretreatment with mevastatin markedly reduced S1P-induced cell migration and COX-2/PGE2 production via a PPARγ-dependent signalling pathway.. Mevastatin attenuates the S1P-induced increased expression of COX-2 and cell migration via the regulation of FoxO1 and CREB phosphorylation and translocation by PPARγ in HTSMCs. Mevastatin could be beneficial for prevention of airway inflammation in the future.

Topics: Animals; Anti-Inflammatory Agents; Bronchoalveolar Lavage Fluid; Cell Movement; Cyclic AMP Response Element-Binding Protein; Cyclooxygenase 2; Dinoprostone; Elafin; Forkhead Box Protein O1; Forkhead Transcription Factors; Humans; Hydrogen Peroxide; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Leukocyte Count; Lovastatin; Lysophospholipids; Male; Membrane Glycoproteins; Mice, Inbred ICR; Myocytes, Smooth Muscle; NADPH Oxidase 2; NADPH Oxidases; Phosphorylation; PPAR gamma; Proto-Oncogene Proteins c-akt; RNA, Small Interfering; Sphingosine; TOR Serine-Threonine Kinases; Trachea