Thrombin induces cyclooxygenase-2 expression via the ERK and NF-kappaB pathways in human lung fibroblasts.
There is growing evidence that increased expression of cyclooxygenase-2 (COX-2) in the lungs of patients is a key event in the pathogenesis of lung diseases. In this study, we investigated the involvement of the extracellular signal-regulated kinase (ERK), IkappaB kinase alpha/beta (IKKalpha/beta), and nuclear factor-kappaB (NF-kappaB) signaling pathways in thrombin-induced COX-2 expression in human lung fibroblasts (WI-38). Treatment of WI-38 cells with thrombin caused increased COX-2 expression in a concentration- and time-dependent manner. Treatment of WI-38 cells with PD 98059 (2-[2-amino-3-methoxyphenyl]-4H-1-benzopyran-4-one, a MEK inhibitor) inhibited thrombin-induced COX-2 expression and COX-2-luciferase activity. Stimulation of cells with thrombin caused an increase in ERK phosphorylation in a time-dependent manner. In addition, treatment of WI-38 cells with Bay 117082, an IkappaB phosphorylation inhibitor, and pyrrolidine dithiocarbamate (PDTC), an NF-kappaB inhibitor, inhibited thrombin-induced COX-2 expression. The thrombin-induced increase in COX-2-luciferase activity was also blocked by the dominant negative IkappaBalpha mutant (IkappaBalphaM). Treatment of WI-38 cells with thrombin induced IKKalpha/beta and IkappaBalpha phosphorylation, IkappaBalpha degradation, and kappaB-luciferase activity. The thrombin-mediated increases in IKKalpha/beta phosphorylation and kappaB-luciferase activity were inhibited by PD 98059. Taken together, these results suggest that the ERK-dependent IKKalpha/beta/NF-kappaB signaling pathway plays an important role in thrombin-induced COX-2 expression in human lung fibroblasts.
Shih
Chung-Huang
CH
Department of Respiratory Therapy, Taipei Medical University Hospital, Taipei, Taiwan.
Bien
Mauo-Ying
MY
Chiang
Ling-Ling
LL
Su
Chien-Ling
CL
Lin
Chien-Huang
CH
Chen
Bing-Chang
BC
D000818:Animals; D002417:Cattle; D002460:Cell Line; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D008168:Lung / Q000166:cytology; D016328:NF-kappa B / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D015398:Signal Transduction / Q000187:drug effects*; D013917:Thrombin / Q000494:pharmacology*; D015533:Transcriptional Activation / Q000187:drug effects*
D016328:NF-kappa B; D008156:Luciferases; D051546:Cyclooxygenase 2; D051550:I-kappa B Kinase; D048049:Extracellular Signal-Regulated MAP Kinases; D013917:Thrombin