Fulltext

Prostacyclin production in rat aortic smooth muscle cells: role of protein kinase C, phospholipase D and cyclooxygenase-2 expression

Frias, Miguel A. ; Dubouloz, Frédérique ; Rebsamen, Michela C. ; Lang, Ursula

In: Cardiovascular Research, 2003, vol. 60, no. 2, p. 438-446

Ajouter à la liste personnelle
    Titre
    • Prostacyclin production in rat aortic smooth muscle cells: role of protein kinase C, phospholipase D and cyclooxygenase-2 expression
    Auteur
    • Frias, Miguel A.. Division of Endocrinology and Diabetology, University Hospital, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland
    • Dubouloz, Frédérique. Division of Endocrinology and Diabetology, University Hospital, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland
    • Rebsamen, Michela C.. Division of Endocrinology and Diabetology, University Hospital, 24 rue Micheli-du-Crest, CH-1211 Geneva 14, Switzerland
    • Lang, Ursula. E-mail: ursula.lang@medecine.unige.ch
    Type de document
    • Postprint
    Identifiant OAI-PMH
    • oai:doc.rero.ch:304573
    Summary
    Objective: The present study was designed to investigate the role of protein kinase C (PKC) and phospholipase D (PLD) in angiotensin II (AngII)- and phorbol ester (PMA)-induced cyclooxygenase-2 (COX-2) expression and prostacyclin (PGI2) production in rat aortic smooth muscle cells (VSMC). Methods: Prostacyclin production in cultured VSMC was determined by radioimmunoassay. PKC activity was examined by measuring the transfer of 32P from (γ-32P)ATP to histone III-S. COX-2 expression was determined by Western blotting. To measure PLD activity, thin layer chromatography was used. Results: AngII (50 nM) and PMA (100 nM) promoted the translocation of PKC activity from the cytosol to the membranes within 30 min, followed by a strong increase in PLD activity as well as COX-2 expression and PGI2 production. After 48 h exposure to PMA, PKC was downregulated resulting in a complete suppression of its activity. PKC-downregulation and the PKC inhibitor CGP41251 abolished PMA- and AngII-induced PLD activation, suppressed the stimulatory effect of PMA on COX-2 expression and PGI2 production and strongly inhibited that of AngII. Furthermore, AngII- and PMA-induced PGI2 production depended on protein synthesis and COX-2 but not COX-1 activity. Inhibition of PLD-mediated phosphatidic acid (PA) formation by 1% 1-butanol abolished AngII-induced COX-2 expression and PGI2 secretion, while dioctanoyl PA increased COX-2 expression and PGI2 production in a time- and concentration-dependent manner. Conclusion: Our results indicate that in VSMC, AngII promotes PGI2 production to a large extent through a rise in COX-2 expression which is mediated by PA generated from increased PKC-dependent PLD activity