Thrombin-induced connective tissue growth factor expression in human lung fibroblasts requires the ASK1/JNK/AP-1 pathway
Journal
Journal of Immunology
Journal Volume
182
Journal Issue
12
Pages
7916-7927
Date Issued
2009
Abstract
Thrombin plays an important role in lung inflammatory diseases. Thrombin can induce connective tissue growth factor (CTGF) expression in lung fibroblasts. However, little is known about the signaling pathway in thrombin-induced CTGF expression. In this study, we investigated the role of apoptosis signal-regulating kinase 1 (ASK1) in thrombin-induced CTGF expression in human lung fibroblasts. Thrombin caused a concentration- and time-dependent increase in CTGF expression in WI-38 cells and primary lung fibroblasts. Thrombin-induced CTGF expression and CTGF-luciferase activity were inhibited by a protease-activated receptor 1 antagonist (SCH79797), the dominant-negative mutants (DNs) of ASK1 and JNK1/2, and an AP-1 inhibitor (curcumin). Thrombin caused ASK1 Ser967 dephosphorylation, the dissociation of ASK1 and 14-3-3, and a subsequent increase in ASK1 activity. Thrombin induced increases in JNK phosphorylation and kinase activity, which were attenuated by ASK1DN. Furthermore, SCH79797 diminished the thrombin-induced ASK1 and JNK activities. Thrombin-induced CTGF-luciferase activity was predominately controlled by the sequence -747 to -184 bp upstream of the transcription start site of the human CTGF promoter and was attenuated by transfection with the deleted AP-1 binding site construct. Thrombin caused increases in c-Jun phosphorylation, the formation of an AP-1-specific DNA-protein complex, and the recruitment of c-Jun to the CTGF promoter. Furthermore, thrombin-mediated AP-1 activation was inhibited by ASK1DN, JNK1/2DN, and SP600125. These results suggest for the first time that thrombin, acting through protease-activated receptor 1, activates the ASK1/JNK signaling pathway, which in turn initiates c-Jun/AP-1 activation and recruitment of c-Jun to the CTGF promoter and ultimately induces CTGF expression in human lung fibroblasts. Copyright ? 2009 by The American Association of Immunologists, Inc.
SDGs
Other Subjects
anthra[1,9 cd]pyrazol 6(2h) one; apoptosis signal regulating kinase 1; connective tissue growth factor; curcumin; Janus kinase; luciferase; protein c jun; proteinase activated receptor 1; thrombin; transcription factor AP 1; apoptosis signal regulating kinase 1; connective tissue growth factor; MAP3K5 protein, human; proteinase activated receptor; stress activated protein kinase; transcription factor AP 1; article; binding site; competitive inhibition; concentration (parameters); controlled study; dephosphorylation; enzyme activity; enzyme phosphorylation; human; human cell; lung fibroblast; molecular dynamics; nucleotide sequence; priority journal; protein expression; signal transduction; cell culture; enzyme activation; fibroblast; genetic transcription; genetics; lung; metabolism; promoter region; signal transduction; Cells, Cultured; Connective Tissue Growth Factor; Enzyme Activation; Fibroblasts; Humans; JNK Mitogen-Activated Protein Kinases; Lung; MAP Kinase Kinase Kinase 5; Promoter Regions, Genetic; Receptors, Proteinase-Activated; Signal Transduction; Transcription Factor AP-1; Transcription, Genetic
Type
journal article