Endothelin-1 induces connective tissue growth factor expression in human lung fibroblasts by ETAR-dependent JNK/AP-1 pathway.
Endothelin-1 (ET-1) acts as a key mediator of vasoconstriction and tissue repair. Overproduction of connective tissue growth factor (CTGF) underlies the development of lung fibrosis. ET-1 induces expression of matrix-associated genes in lung fibroblasts, however, little is known about the signaling pathway of CTGF expression caused by ET-1. In this study, we found that ET-1 caused concentration- and time-dependently increases in CTGF expression in human embryonic lung fibroblast cell line (WI-38). ET-1-induced CTGF expression was inhibited by BQ123 (ETAR antagonist), but not BQ788 (ETBR antagonist). Moreover, ET-1-induced CTGF expression was significantly reduced by JNK inhibitor (SP600125), the dominant-negative mutants of JNK1/2 (JNK1/2 DN), and AP-1 inhibitor (curcumin). ET-1 induced phosphorylations of JNK and c-Jun in time-dependent manners. AP-1 luciferase activity was concentration-dependently increased by ET-1, and this effect was attenuated by SP600125. We also found that ET-1-induced CTGF expression was most controlled by the AP-1 binding region of CTGF promoter. ET-1-indiced CTGF luciferase activity was predominately controlled by the sequence -747 to -408 bp upstream of the transcription start site on the human CTGF promoter. Furthermore, ET-1 caused the formation of AP-1-specific DNA-protein complex and the recruitment of c-Jun to the CTGF promoter. Moreover, we found that ET-1 induced α-smooth muscle actin (α-SMA) expression, which was inhibited by BQ123, SP600125, curcumin, and anti-CTGF antibody. These results suggest that ET-1 stimulates expressions of CTGF and α-SMA through ETAR/JNK/AP-1 signaling pathway, and CTGF is required for ET-1-induced α-SMA expression in human lung fibroblasts.
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
Chih-Ming
CM
Weng
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan.
Chung-Chi
CC
Yu
Graduate Institute of Toxicology, College of Medicine, National Taiwan University, Taipei 100, Taiwan; Graduate Institute of Biomedical Sciences, College of Life Science, National Taiwan University, Taipei 106, Taiwan.
Min-Liang
ML
Kuo
School of Respiratory Therapy, College of Medicine, Taipei Medical University, 250 Wu-Hsing Street, Taipei 11031, Taiwan. Electronic address: bcchen@tmu.edu.tw.
Bing-Chang
BC
Chen
Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei 11031, Taiwan. Electronic address: chlin@tmu.edu.tw.
Chien-Huang
CH
Lin
D000199:Actins / Q000378:metabolism; D001665:Binding Sites; D002460:Cell Line; D055513:Connective Tissue Growth Factor / Q000235:genetics / Q000378:metabolism*; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism* / Q000494:pharmacology; D005347:Fibroblasts / Q000378:metabolism*; D006801:Humans; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008168:Lung / Q000166:cytology / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D044022:Receptor, Endothelin A / Q000378:metabolism*; D015398:Signal Transduction; D018808:Transcription Factor AP-1 / Q000378:metabolism*
C541116:ACTA2 protein, human; D000199:Actins; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1; D044022:Receptor, Endothelin A; D018808:Transcription Factor AP-1; D055513:Connective Tissue Growth Factor; D048031:JNK Mitogen-Activated Protein Kinases
Activator protein-1; Connective tissue growth factor; Endothelin A receptor; Endothelin-1; α-Smooth muscle actin