Sphingosylphosphorylcholine potentiates vasoreactivity and voltage-gated Ca2+ entry via NOX1 and reactive oxygen species. (6th February 2015)

• Record Type: Journal Article
• Authors: Shaifta, Yasin; Snetkov, Vladimir A.; Prieto-Lloret, Jesus; Knock, Greg A.; Smirnov, Sergey V.; Aaronson, Philip I.; Ward, Jeremy P.T.
• Is Part Of: Cardiovascular research. Volume 106:Number 1(2015)
• Page Start: 121
• Page End: 130
• Publication Date: 2015-02-06
• Subjects: NADPH oxidase -- Vascular smooth muscle -- L-type Ca2+ channels -- Protein kinase C epsilon -- Reactive oxygen species; Cardiovascular system -- Diseases -- Periodicals; Cardiovascular system -- Periodicals; 616.1
• DOI: 10.1093/cvr/cvv029
• Languages: English
• ISSNs: 0008-6363

Abstract

Abstract: Aims: Sphingosylphosphorylcholine (SPC) elicits vasoconstriction at micromolar concentrations. At lower concentrations (≤1 µmol/L), however, it does not constrict intrapulmonary arteries (IPAs), but strongly potentiates vasoreactivity. Our aim was to determine whether this also occurs in a systemic artery and to delineate the signalling pathway. Methods and results: Rat mesenteric arteries and IPAs mounted on a myograph were challenged with ∼25 mmol/L [K + ] to induce a small vasoconstriction. SPC (1 µmol/L) dramatically potentiated this constriction in all arteries by ∼400%. The potentiation was greatly suppressed or abolished by inhibition of phospholipase C (PLC; U73122), PKCε (inhibitory peptide), Src (PP2), and NADPH oxidase (VAS2870), and also by Tempol (superoxide scavenger), but not by inhibition of Rho kinase (Y27632). Potentiation was lost in mesenteric arteries from p47 phox–/–, but not NOX2 −/–, mice. The intracellular superoxide generator LY83583 mimicked the effect of SPC. SPC elevated reactive oxygen species (ROS) in vascular smooth muscle cells, and this was blocked by PP2, VAS2870, and siRNA knockdown of PKCε. SPC (1 µmol/L) significantly reduced the EC50 for U46619-induced vasoconstriction, an action ablated by Tempol. In patch-clamped mesenteric artery cells, SPC (200 nmol/L) enhanced Ba 2+ current through L-type Ca 2+ channels, an action abolished by Tempol but mimicked by LY83583. Conclusion: Our results suggest that low concentrations of SPC activate a PLC-coupled and NOX1-mediated increase in ROS, with consequent enhancement of voltage-gated Ca 2+ entry and thus vasoreactivity. We speculate that this pathway is not specific for SPC, but may also contribute to vasoconstriction elicited by other G-protein coupled receptor and PLC-coupled agonists.