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Activation of Galpha s mediates induction of tissue-type plasminogen activator gene transcription by epoxyeicosatrienoic acids

J Biol Chem. 2001 May 11;276(19):15983-9. doi: 10.1074/jbc.M100439200. Epub 2001 Feb 22.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • 8,11,14-Eicosatrienoic Acid / analogs & derivatives*
  • 8,11,14-Eicosatrienoic Acid / pharmacology*
  • Animals
  • Aorta
  • Atropine Derivatives
  • Cattle
  • Cells, Cultured
  • Cyclic AMP / metabolism
  • Cytochrome P-450 CYP2J2
  • Cytochrome P-450 Enzyme System / metabolism*
  • Endothelium, Vascular / enzymology*
  • GTP-Binding Protein alpha Subunits, Gi-Go / metabolism
  • GTP-Binding Protein alpha Subunits, Gs / metabolism*
  • Gene Expression Regulation, Enzymologic / drug effects
  • Gene Expression Regulation, Enzymologic / physiology*
  • Humans
  • Oxygenases / metabolism*
  • Polymerase Chain Reaction
  • Proadifen / pharmacology
  • Promoter Regions, Genetic
  • Saphenous Vein
  • Tissue Plasminogen Activator / genetics*
  • Transcription, Genetic / drug effects
  • Transcription, Genetic / physiology*
  • Transfection

Substances

  • Atropine Derivatives
  • CYP2J2 protein, human
  • 11,12-epoxy-5,8,14-eicosatrienoic acid
  • SK&F 21000
  • 5,6-epoxy-8,11,14-eicosatrienoic acid
  • 8,9-epoxyeicosatrienoic acid
  • 14,15-epoxy-5,8,11-eicosatrienoic acid
  • Cytochrome P-450 Enzyme System
  • Proadifen
  • Cyclic AMP
  • Oxygenases
  • Cytochrome P-450 CYP2J2
  • Tissue Plasminogen Activator
  • GTP-Binding Protein alpha Subunits, Gi-Go
  • GTP-Binding Protein alpha Subunits, Gs
  • 8,11,14-Eicosatrienoic Acid