Activation of Galpha s mediates induction of tissue-type plasminogen activator gene transcription by epoxyeicosatrienoic acids.
The epoxyeicosatrienoic acids (EETs) are products of cytochrome P450 (CYP) epoxygenases that have vasodilatory and anti-inflammatory properties. Here we report that EETs have additional fibrinolytic properties. In vascular endothelial cells, physiological concentrations of EETs, particularly 11,12-EET, or overexpression of the endothelial epoxygenase, CYP2J2, increased tissue plasminogen activator (t-PA) expression by 2.5-fold without affecting plasminogen activator inhibitor-1 expression. This increase in t-PA expression correlated with a 4-fold induction in t-PA gene transcription and a 3-fold increase in t-PA fibrinolytic activity and was blocked by the CYP inhibitor, SKF525A, but not by the calcium-activated potassium channel blocker, charybdotoxin, indicating a mechanism that does not involve endothelial cell hyperpolarization. The t-PA promoter is cAMP-responsive, and induction of t-PA gene transcription by EETs correlated with increases in intracellular cAMP levels and, functionally, with cAMP-driven promoter activity. To determine whether increases in intracellular cAMP levels were due to modulation of guanine nucleotide-binding proteins, we assessed the effects of EETs on Galpha(s) and Galpha(i2). Treatment with EETs increased Galpha(s), but not Galpha(i2), GTP-binding activity by 3.5-fold. These findings indicate that EETs possess fibrinolytic properties through the induction of t-PA and suggest that endothelial CYP2J2 may play an important role in regulating vascular hemostasis.
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Cardiovascular Division, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
Ruan
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Dai
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Yang
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Graham
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Zeldin
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Liao
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D015126:8,11,14-Eicosatrienoic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D001011:Aorta; D001286:Atropine Derivatives; D002417:Cattle; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D000090762:Cytochrome P-450 CYP2J2; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000201:enzymology*; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism; D019205:GTP-Binding Protein alpha Subunits, Gs / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D010105:Oxygenases / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011335:Proadifen / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012501:Saphenous Vein; D010959:Tissue Plasminogen Activator / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects / Q000502:physiology*; D014162:Transfection
D001286:Atropine Derivatives; C000717350:CYP2J2 protein, human; C046783:11,12-epoxy-5,8,14-eicosatrienoic acid; C006271:SK&F 21000; C040776:5,6-epoxy-8,11,14-eicosatrienoic acid; C050715:8,9-epoxyeicosatrienoic acid; C046782:14,15-epoxy-5,8,11-eicosatrienoic acid; D003577:Cytochrome P-450 Enzyme System; D011335:Proadifen; D000242:Cyclic AMP; D010105:Oxygenases; D000090762:Cytochrome P-450 CYP2J2; D010959:Tissue Plasminogen Activator; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D019205:GTP-Binding Protein alpha Subunits, Gs; D015126:8,11,14-Eicosatrienoic Acid