TY - JOUR
T1 - Crucial role of extracellular signal-regulated kinase pathway in reactive oxygen species-mediated endothelin-1 gene expression induced by endothelin-1 in rat cardiac fibroblasts
AU - Cheng, Cheng Ming
AU - Hong, Hong Jye
AU - Liu, Ju Chi
AU - Shih, Neng Lang
AU - Juan, Shu Hui
AU - Loh, Shih Hurng
AU - Chan, Paul
AU - Chen, Jin Jer
AU - Cheng, Tzu-Hurng
PY - 2003/5/1
Y1 - 2003/5/1
N2 - Endothelin-1 (ET-1) has been implicated in fibroblast proliferation. However, the mechanism involving ET-1 is not clear., The present study was performed to examine the role of endogenous ET-1 in ET-1 - stimulated fibroblast proliferation and to investigate the regulatory mechanism of ET-1 - induced ET-1 gene expression in cardiac fibroblasts. Both ETA receptor antagonist [(hexahydro-1 H-azepinyl)carbonyl-Leu-D-Trp-D-OH (BQ485)] and endothelin-converting enzyme inhibitor (phosphoramidon) inhibited the increased DNA synthesis caused by ET-1. ET-1 gene was induced by ET-1, as revealed with Northern blotting and ET-1 promoter activity assay. ET-1 increased intracellular reactive oxygen species (ROS), which were significantly inhibited by BQ485 and antioxidants. Antioxidants suppressed ET-1 gene expression and DNA synthesis stimulated by ET-1. ET-1 activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), p38 MAPK, and c-Jun N-terminal kinase, which were significantly inhibited by antioxidants. Only ERK inhibitor U0126 could inhibit ET-1 - induced transcription of the ET-1 gene. Cotransfection of dominant-negative mutant of Ras, Raf, and MEK1 decreased the ET-1 - induced increase in ET-1 transcription, suggesting that the Ras-Raf-ERK pathway is required for ET-1 action. Truncation and mutational analysis of the ET-1 gene promoter showed that the activator protein-1 (AP-1) binding site was an important cis-element in ET-1 - induced ET-1 gene expression. Antioxidants attenuated the ET-1 - stimulated AP-1 binding activity. Our data suggest that ROS were involved in ET-1 - induced fibroblast proliferation and mediated ET-1induced activation of ERK pathways, which culminated in ET-1 gene expression.
AB - Endothelin-1 (ET-1) has been implicated in fibroblast proliferation. However, the mechanism involving ET-1 is not clear., The present study was performed to examine the role of endogenous ET-1 in ET-1 - stimulated fibroblast proliferation and to investigate the regulatory mechanism of ET-1 - induced ET-1 gene expression in cardiac fibroblasts. Both ETA receptor antagonist [(hexahydro-1 H-azepinyl)carbonyl-Leu-D-Trp-D-OH (BQ485)] and endothelin-converting enzyme inhibitor (phosphoramidon) inhibited the increased DNA synthesis caused by ET-1. ET-1 gene was induced by ET-1, as revealed with Northern blotting and ET-1 promoter activity assay. ET-1 increased intracellular reactive oxygen species (ROS), which were significantly inhibited by BQ485 and antioxidants. Antioxidants suppressed ET-1 gene expression and DNA synthesis stimulated by ET-1. ET-1 activated mitogen-activated protein kinases (MAPK), including extracellular signal-regulated kinase (ERK), p38 MAPK, and c-Jun N-terminal kinase, which were significantly inhibited by antioxidants. Only ERK inhibitor U0126 could inhibit ET-1 - induced transcription of the ET-1 gene. Cotransfection of dominant-negative mutant of Ras, Raf, and MEK1 decreased the ET-1 - induced increase in ET-1 transcription, suggesting that the Ras-Raf-ERK pathway is required for ET-1 action. Truncation and mutational analysis of the ET-1 gene promoter showed that the activator protein-1 (AP-1) binding site was an important cis-element in ET-1 - induced ET-1 gene expression. Antioxidants attenuated the ET-1 - stimulated AP-1 binding activity. Our data suggest that ROS were involved in ET-1 - induced fibroblast proliferation and mediated ET-1induced activation of ERK pathways, which culminated in ET-1 gene expression.
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U2 - 10.1124/mol.63.5.1002
DO - 10.1124/mol.63.5.1002
M3 - Article
C2 - 12695528
AN - SCOPUS:0037731448
SN - 0026-895X
VL - 63
SP - 1002
EP - 1011
JO - Molecular Pharmacology
JF - Molecular Pharmacology
IS - 5
ER -