Epoxyeicosatrienoic acids regulate Trp channel-dependent Ca2+ signaling and hyperpolarization in endothelial cells

Ingrid Fleming, Alexandra Rueben, Rüdiger Popp, Beate Fisslthaler, Susanne Schrodt, Anna Sander, Judith Haendeler, John R. Falck, Christophe Morisseau, Bruce D. Hammock, Rudi Busse

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132 Scopus citations

Abstract

OBJECTIVE - An initial step in endothelium-derived hyperpolarizing factor-mediated responses is endothelial cell hyperpolarization. Here we address the mechanisms by which cytochrome P450 (CYP)-derived epoxyeicosatrienoic acids (EETs) contribute to this effect in native and cultured endothelial cells. METHODS AND RESULTS - In native CYP2C-expressing endothelial cells, bradykinin elicited a Ca influx that was potentiated by the soluble epoxide hydrolase inhibitor, 1-adamantyl-3-cyclohexylurea (ACU), and attenuated by CYP inhibition. Similar effects were observed in cultured endothelial cells overexpressing CYP2C9, but not in CYP2C9-deficient cells, and were prevented by the EET antagonist 14,15-epoxyeicosa-5(Z)-enoic acid as well as by the cAMP antagonist, Rp-cAMPS. The effects on Ca were mirrored by prolongation of the bradykinin-induced hyperpolarization. Ruthenium red and the combination of charybdotoxin and apamin prevented the latter effect, suggesting that Trp channel activation increases Ca influx and prolongs the activation of Ca-dependent K (KCa) channels. Indeed, overexpression of CYP2C9 enhanced the agonist-induced translocation of a TrpC6-V5 fusion protein to caveolin-1-rich areas of the endothelial cell membrane, which was prevented by Rp-cAMPS and mimicked by 11,12-EET. CONCLUSIONS - Elevated EET levels regulate Ca influx into endothelial cells and the subsequent activation of KCa channels, via a cAMP/PKA-dependent mechanism that involves the intracellular translocation of Trp channels.

Original languageEnglish (US)
Pages (from-to)2612-2618
Number of pages7
JournalArteriosclerosis, Thrombosis, and Vascular Biology
Volume27
Issue number12
DOIs
StatePublished - Dec 2007

Keywords

  • Caveolae
  • Cytochrome P450
  • Endothelium-derived hyperpolarizing factor
  • Protein kinase A

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine

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    Fleming, I., Rueben, A., Popp, R., Fisslthaler, B., Schrodt, S., Sander, A., Haendeler, J., Falck, J. R., Morisseau, C., Hammock, B. D., & Busse, R. (2007). Epoxyeicosatrienoic acids regulate Trp channel-dependent Ca2+ signaling and hyperpolarization in endothelial cells. Arteriosclerosis, Thrombosis, and Vascular Biology, 27(12), 2612-2618. https://doi.org/10.1161/ATVBAHA.107.152074