Thrombin induces endothelin expression in arterial smooth muscle cells.
Thrombin has been shown to stimulate endothelin release by endothelial cells, but the ability of thrombin to induce endothelin in nonendothelial cells is less well-known. Incubation of rat aortic smooth muscle cells with thrombin resulted in a stimulation of preproendothelin-1 (preproET-1) mRNA expression. This induction of preproET-1 mRNA expression by thrombin was accompanied by the release of immunoreactive peptide ET-1 into the extracellular medium. The synthetic thrombin receptor activator peptide (TRAP) confirmed ligand-specific receptor action to induce preproET-1 mRNA. Nuclear run-on analysis revealed that the transcriptional rate of preproET-1 mRNA increases twofold after 1 h of incubation with thrombin. In cells treated with thrombin, the half-life of preproET-1 mRNA was identical to that in untreated control cells. These results demonstrated that thrombin regulates endothelin synthesis at a transcriptional level but does not influence mRNA stability. Inhibition of protein kinase C (PKC) with selective inhibitors (chelerythrine and bisindolylmaleimide I) before thrombin stimulation failed to significantly inhibit preproET-1 gene expression. Inhibition of mitogen-activated protein (MAP) kinase kinase and protein tyrosine kinase decreased preproET-1 mRNA expression in thrombin-stimulated smooth muscle cells. Furthermore, addition of an activator of peroxisome proliferator-activated receptors-alpha (PPARalpha), fenofibrate, prevented the preproET-1 gene induction in response to thrombin. These results demonstrated that thrombin-induced endothelin gene transcription involved MAP kinase kinase rather than the PKC cascade in smooth muscle cells, which was repressed by PPARalpha stimulation.
Lepailleur-Enouf
D
D
Institut National de la Santé et de la Recherche Médicale U460, UFR X. Bichat, 75018 Paris, France.
Valdenaire
O
O
Philippe
M
M
Jandrot-Perrus
M
M
Michel
J B
JB
D000818:Animals; D001011:Aorta; D001158:Arteries / Q000187:drug effects / Q000378:metabolism*; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000235:genetics / Q000378:metabolism; D016232:Endothelins / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression / Q000187:drug effects; D016014:Linear Models; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010446:Peptide Fragments / Q000494:pharmacology; D011493:Protein Kinase C / Q000187:drug effects / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis* / Q000235:genetics; D011506:Proteins / Q000494:pharmacology; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors; D020871:RNA Stability / Q000187:drug effects; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D044463:Receptor, PAR-1; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D018179:Receptors, Thrombin / Q000378:metabolism; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D013917:Thrombin / Q000378:metabolism* / Q000494:pharmacology; D014157:Transcription Factors / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
D019332:Endothelin-1; D016232:Endothelins; D004791:Enzyme Inhibitors; D010446:Peptide Fragments; D011498:Protein Precursors; D011506:Proteins; D012333:RNA, Messenger; D044463:Receptor, PAR-1; D018160:Receptors, Cytoplasmic and Nuclear; D018179:Receptors, Thrombin; D014157:Transcription Factors; D011493:Protein Kinase C; D012319:RNA Polymerase II; D013917:Thrombin; D013755:Tetradecanoylphorbol Acetate