Peroxisome proliferator-activated receptor activators inhibit thrombin-induced endothelin-1 production in human vascular endothelial cells by inhibiting the activator protein-1 signaling pathway.
Endothelin-1 (ET-1), a 21-amino acid vasoactive peptide mainly produced by vascular endothelial cells, is involved in the regulation of vascular tone and smooth muscle cell proliferation. Peroxisome proliferator-activated receptors (PPARs), key players in lipid and glucose metabolism, have been implicated in metabolic disorders that are predisposing to atherosclerosis. Because of the potential role of ET-1 in vascular disorders such as hypertension and atherosclerosis, we investigated the regulation of ET-1 expression by PPAR activators. Western blot and reverse transcription-polymerase chain reaction analyses demonstrated that both PPARalpha and PPARgamma are expressed in human coronary artery endothelial cells as well as in endothelial cell lines such as HMEC-1 and ECV304. In bovine aortic endothelial cells and HMEC-1 cells, both PPARalpha and PPARgamma ligands inhibited thrombin-induced ET-1 secretion, whereas basal ET-1 secretion was only slightly suppressed. Reverse transcription-polymerase chain reaction experiments showed that this inhibition of ET-1 production occurs at the gene expression level. Using transient transfection assays, we demonstrated that PPARs downregulate thrombin-activated transcription of the human ET-1 promoter. Transactivation studies with c-Jun and c-Fos expression plasmids indicated that PPARs negatively interfere with the activator protein-1 signaling pathway, which mediates thrombin activation of ET-1 gene transcription. Furthermore, electrophoretic mobility shift assays demonstrated that PPAR activators reduce the thrombin-stimulated binding activity of bovine aortic endothelial cell nuclear extracts as well as c-Jun binding to an activator protein-1 consensus site. Taken together, these data indicate that (1) both PPARalpha and PPARgamma are expressed in human vascular endothelial cells and (2) PPAR activators inhibit thrombin-induced ET-1 biosynthesis, indicating a novel role for PPARs in vascular endothelial function.
Delerive
P
P
U.325 INSERM, Département d'Athérosclérose, Institut Pasteur de Lille, Lille, France.
Martin-Nizard
F
F
Chinetti
G
G
Trottein
F
F
Fruchart
J C
JC
Najib
J
J
Duriez
P
P
Staels
B
B
D000818:Animals; D001011:Aorta / Q000166:cytology; D001161:Arteriosclerosis / Q000503:physiopathology; D002196:Capillaries / Q000166:cytology; D002417:Cattle; D003331:Coronary Vessels / Q000166:cytology; D004247:DNA / Q000235:genetics / Q000378:metabolism; D019332:Endothelin-1 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D020025:Peroxisome Proliferators / Q000494:pharmacology*; D011401:Promoter Regions, Genetic; D011485:Protein Binding / Q000187:drug effects; D016760:Proto-Oncogene Proteins c-fos / Q000502:physiology; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects*; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D018808:Transcription Factor AP-1 / Q000037:antagonists & inhibitors* / Q000502:physiology; D014157:Transcription Factors / Q000187:drug effects / Q000502:physiology*; D014158:Transcription, Genetic; D014162:Transfection
D019332:Endothelin-1; D020025:Peroxisome Proliferators; D016760:Proto-Oncogene Proteins c-fos; D018160:Receptors, Cytoplasmic and Nuclear; D018808:Transcription Factor AP-1; D014157:Transcription Factors; D004247:DNA; D013917:Thrombin