Consumption of the flavonoid quercetin exerts beneficial effects on many chronic diseases. The mechanisms involved in the vasorelaxant effect of quercetin remain uncertain. In the present study, we examined the role of quercetin in vasodilation and rapid endothelial nitric oxide synthase (eNOS) activity in endothelial cells. Quercetin induced a rapid, dose-dependent phosphorylation of eNOS at serine 1179. PKA, Akt and ERK1/2 were all quickly phosphorylated in the process too, but not AMPK and CaMK II. The specific kinase inhibitors for Akt or ERK1/2 could not abolish the quercetin-induced eNOS phosphorylation at Ser1179, which, however, was significantly abolished by H89, an inhibitor of PKA. Concomitantly, intracellular cAMP production was quickly increased by quercetin stimulation and an adenylate cyclase activator, forskolin, also induced eNOS phosphorylation at Ser1179. Quercetin enhanced nitric oxide (NO) production, which was abolished by an eNOS inhibitor, L-NAME or H89. Quercetin exerted a vasodilatory effect on rings with an intact endothelium but not on endothelium-deprived rings, and also inhibited vascular contractility induced by angiotensin II or phenylephrine in rat aortic rings. We conclude that quercetin quickly phosphorylates eNOS at Ser1179 via an Akt-independent, cAMP/PKA-mediated pathway to enhance the production of NO and to promote vasodilation.

Keywords:
Quercetin, eNOS, Phosphorylation, PKA, Endothelial cells
1.
Hisamoto K, Ohmichi M, Kanda Y, Adachi K, Nishio Y, Hayakawa J, Mabuchi S, Takahashi K, Tasaka K, Miyamoto Y, Taniguchi N, Murata Y: Induction of endothelial nitric-oxide synthase phosphorylation by the raloxifene analog LY117018 is differentially mediated by Akt and extracellular signal-regulated protein kinase in vascular endothelial cells. J Biol Chem 2001;276:47642–47649.
2.
Mineo C, Yuhanna IS, Quon MJ, Shaul PW: High density lipoprotein-induced endothelial nitric-oxide synthase activation is mediated by Akt and MAP kinases. J Biol Chem 2003;278:9142–9149.
3.
Bernier SG, Haldar S, Michel T: Bradykinin-regulated interactions of the mitogen-activated protein kinase pathway with the endothelial nitric-oxide synthase. J Biol Chem 2000;275:30707–30715.
4.
Michell BJ, Chen Zp, Tiganis T, Stapleton D, Katsis F, Power DA, Sim AT, Kemp BE: Coordinated control of endothelial nitric-oxide synthase phosphorylation by protein kinase C and the cAMP-dependent protein kinase. J Biol Chem 2001;276:17625–17628.
5.
Boo YC, Sorescu G, Boyd N, Shiojima I, Walsh K, Du J, Jo H: Shear stress stimulates phosphorylation of endothelial nitric-oxide synthase at Ser1179 by Akt-independent mechanisms: role of protein kinase A. J Biol Chem 2002;277:3388–3396.
6.
Lorenz M, Wessler S, Follmann E, Michaelis W, Dusterhoft T, Baumann G, Stangl K, Stangl V: A constituent of green tea, epigallocatechin-3-gallate, activates endothelial nitric oxide synthase by a phosphatidylinositol-3-OH-kinase-, cAMP-dependent protein kinase-, and Akt-dependent pathway and leads to endothelial-dependent vasorelaxation. J Biol Chem 2004;279:6190–6195.
7.
Liu D, Homan LL, Dillon JS: Genistein acutely stimulates nitric oxide synthesis in vascular endothelial cells by a cyclic adenosine 5′-monophosphate-dependent mechanism. Endocrinology 2004;145:5532–5539.
8.
Xu JW, Ikeda K, Yamori Y: Cyanidin-3-glucoside regulates phosphorylation of endothelial nitric oxide synthase. FEBS Lett 2004;574:176–180.
9.
Knekt P, Kumpulainen J, Järvinen R, Rissanen H, Heliövaara M, Reunanen A, Hakulinen T, Aromaa A: Flavonoid intake and risk of chronic diseases. Am J Clin Nutr 2002;76:560–568.
10.
Geleijnse JM, Launer LJ, Van der Kuip DA, Hofman A, Witteman JC: Inverse association of tea and flavonoid intakes with incident myocardial infarction: the Rotterdam Study. Am J Clin Nutr 2002;75:880–886.
11.
Loke WM, Hodgson JM, Proudfoot JM, McKinley AJ, Puddey IB, Croft KD: Pure dietary flavonoids quercetin and (–)-epicatechin augment nitric oxide products and reduce endothelin-1 acutely in healthy men. Am J Clin Nutr 2008;88:1018–1025.
12.
Benito S, Lopez D, Sáiz MP, Buxaderas S, Sánchez J, Puig-Parellada P, Mitjavila MT: A flavonoid-rich diet increases nitric oxide production in rat aorta. Br J Pharmacol 2002;135:910–916.
13.
Galisteo M, García-Saura MF, Jiménez R, Villar IC, Wangensteen R, Zarzuelo A, Vargas F, Duarte J: Effects of quercetin treatment on vascular function in deoxycorticosterone acetate-salt hypertensive rats. Comparative study with verapamil. Planta Med 2004;70:334–341.
14.
Suri S, Liu XH, Rayment S, Hughes DA, Kroon PA, Needs PW, Taylor MA, Tribolo S, Wilson VG: Quercetin and its major metabolites selectively modulate cyclic GMP-dependent relaxations and associated tolerance in pig isolated coronary artery. Br J Pharmacol 2010;159:566–575.
15.
Rendig SV, Symons JD, Longhurst JC, Amsterdam EA: Effects of red wine, alcohol, and quercetin on coronary resistance and conductance arteries. J Cardiovasc Pharmacol 2001;38:219–227.
16.
Angelone T, Pasqua T, Di Majo D, Quintieri AM, Filice E, Amodio N, Tota B, Giammanco M, Cerra MC: Distinct signalling mechanisms are involved in the dissimilar myocardial and coronary effects elicited by quercetin and myricetin, two red wine flavonols. Nutr Metab Cardiovasc Dis 2011;21:362–371.
17.
Khoo NK, White CR, Pozzo-Miller L, Zhou F, Constance C, Inoue T, Patel RP, Parks DA: Dietary flavonoid quercetin stimulates vasorelaxation in aortic vessels. Free Radic Biol Med 2010;49:339–347.
18.
Xu JW, Ikeda K, Yamori Y: Upregulation of endothelial nitric oxide synthase by cyanidin-3-glucoside, a typical anthocyanin pigment. Hypertension 2004;44:217–222.
19.
Kojima H, Hirotani M, Nakatsubo N, Kikuchi K, Urano Y, Higuchi T, Hirata Y, Nagano T: Bioimaging of nitric oxide with fluorescent indicators based on the rhodamine chromophore. Anal Chem 2001;73:1967–1973.
20.
Bae SW, Kim HS, Cha YN, Park YS, Jo SA, Jo I: Rapid increase in endothelial nitric oxide production by bradykinin is mediated by protein kinase A signaling pathway. Biochem Biophys Res Commun 2003;306:981–987.
21.
Michell BJ, Harris MB, Chen ZP, Ju H, Venema VJ, Blackstone MA, et al: Identification of regulatory sites of phosphorylation of the bovine endothelial nitric-oxide synthase at serine 617 and serine 635. J Biol Chem 2002;277:42344–42351.
22.
Kuppusamy UR, Das NP: Effects of flavonoids on cyclic AMP phosphodiesterase and lipid mobilization in rat adipocytes. Biochem Pharmacol 1992;44:1307–1315.
23.
Nikaido T, Ohmoto T, Sankawa U, Hamanaka T, Totsuka K: Inhibition of cyclic AMP phosphodiesterase by flavonoids. Planta Med 1982;46:162–166.
24.
Beretz A, Anton R, Stoclet JC: Flavonoid compounds are potent inhibitors of cyclic AMP phosphodiesterase. Experientia 1978;34:1054–1055.
25.
Filippa N, Sable CL, Filloux C, Hemmings B, Van Obberghen E: Mechanism of protein kinase B activation by cyclic AMP-dependent protein kinase. Mol Cell Biol 1999;19:4989–5000.
26.
Enserink JM, Christensen AE, de Rooij J, van Triest M, Schwede F, Genieser HG, et al: A novel Epac-specific cAMP analogue demonstrates independent regulation of Rap1 and ERK. Nat Cell Biol 2002;4:901–906.
27.
Vuchak LA, Tsygankova OM, Prendergast GV, Meinkoth JL: Protein kinase A and B-Raf mediate extracellular signal-regulated kinase activation by thyrotropin. Mol Pharmacol 2009;76:1123–1129.
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2012
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