Introduction Production of endothelin by endothelial cells depends on protein-kinase C (PKC) stimulation which has been reported to be inhibited by alpha-tocopherol (α-Toch) but not by beta-tocopherol (β-Toch). The goal of this study was to determine whether α-Toch and β-Toch inhibit endothelin secretion by endothelial cells.
Methods and results In a first set of experiments, cultured bovine aortic endothelial cells (BAEC) were incubated for 48 h with 100 μmol/l α-Toch or vehicle (0.1% ethanol), then cells were stimulated for 4 h or 20 h with thrombin. After stimulating bovine aortic endothelial cells with thrombin for 4 h, α-Toch inhibited PKC activity by 63% and endothelin secretion by 44%, whereas after 20 h of incubation with thrombin, α-Toch decreased the peptide secretion by 51%. In a second set of experiments, BAEC were incubated with increased concentrations (from 0 to 100 μmol/l) of α-Toch or β-Toch, PKC activity and endothelin secretion were measured after thrombin stimulation as previously reported. In these experiments, α-Toch strongly inhibited thrombin-induced PKC activity and endothelin secretion in a dose-dependent manner, whereas β-Toch was more than 10-fold less active than α-Toch in inhibiting these stimulations. Tocopherols (α-Toch + β-Toch) produced a proportional correlation on both PKC stimulation and endothelin secretion by inhibiting the effect of thrombin.
Conclusion These data suggest that α-Toch strongly inhibits thrombin-induced endothelin secretion in vitro at least partly through PKC inhibition.
YanigasawaMKuriharaHKimuraSTomobeYKobayashiMMitsuiYA novel potent vasoconstrictor peptide produced by vascular endothelial cellsNature1988; 332: 411–415.
2.
DubinDPrattRECookeJEDzauVJ.Endothelin, a potent vasoconstrictor, is a vascular smooth muscle mitogenJ Vasc Med Biol1989; 1: 150–154.
3.
AchmadTHRaoGS.Chemotaxis of human blood monocytes towards endothelin-1 and the influence of calcium channel blockersBiochem Biophys Res Commun1992; 189: 994–1000.
4.
McCarronRMWangLStanimirovicDBSpatzM.Endothelin induction of adhesion molecule expression on human brain microvascular endothelial cellsNeurosci Lett1993; 156: 31–34.
5.
WinklesJAAlbertsGFBrogiELibbyP.Endothelin-1 and endothelin receptor mRNA expression in normal and atherosclerotic human arteriesBiochem Biophys Res Commun1993; 191: 1081–1088.
6.
LermanAEdwardsBSHallettJWHeublinDMSanbergSMBurnettJC.Circulating and tissue endothelin immunoreactivity in advanced atherosclerosisN Engl J Med1991; 325: 997–1001.
7.
ZeiherAMIhlingCPistoriusKSchächingerVSchaeferH-E.Increased tissue endothelin immunoreactivity in atherosclerotic lesions associated with acute coronary syndromesLancet1994; 344: 1405–1406.
8.
IhlingCGöbelHRLippoldAWesselsSPaulMSchaeferHEZeiherAM.Endothelin-1-like immunoreactivity in human atherosclerotic coronary tissue: A detailed analysis of the cellular distribution of endothelin-1J Pathol1996; 179: 303–308.
9.
JonesGTvan RijAMSolomonCThomsonIAPackerSGK.Endothelin-1 is increased overlying atherosclerotic plaques in human arteriesAtherosclerosis1996; 124: 25–35.
10.
SchiniVBHendricksonHHeubleinDMBurnettJCJrVanhouttePM.Thrombin enhances the release of endothelin from cultured porcine aortic endothelial cellsEur J Pharmacol1989; 165: 333–334.
11.
KohnoMYasunariKYolokawaKMurakawaKIHorioTKanayamaYThrombin stimulates the production of immunoreactive endothelin-1 in cultured human umbilical vein endothelial cellsMetabolism1990; 39: 1002–1005.
12.
KohnoMYokokawaKHorioTYasunariKMurakawaKIIkedaMTakedaT.Release mechanism of endothelin-1 and big endothelin-1 after stimulation with thrombin in cultured porcine endothelial cellsJ Vasc Res1992; 29: 56–63.
13.
MarsenTASimonsonMSDunnMJ.Thrombin induces the preproendothelin-1 gene in endothelial cells by protein tyrosine kinase-linked mechanismCirc Res1995; 76: 987–995.
14.
RiemersmaRAWoodDAMacintyreCCHEltonRAGeyKFOliverM.Risk of angina pectoris and plasma concentrations of vitamins A, C, E and caroteneLancet1991; 337: 1–5.
15.
RimmEBStampferMJAscherioAGiovannucciEColditzGAWillettWC.Vitamin E consumption and the risk of coronary heart disease in menN Engl J Med1993; 328: 1450–1456.
16.
StampferMJHennekensCHMansonJEColditzGARosnerBWillnettW.Vitamin E consumption and the risk of coronary disease in womenN Engl J Med1993; 328: 1444–1449.
17.
StephensNGParsonsASchofieldPMKellyFCheesemanKMitchinsonMJ.Randomised controlled trial of vitamin E in patients with coronary disease: Cambridge Heart Antioxidant Study (CHAOS)Lancet1996; 347: 781–786.
18.
WitztumJLSteinbergD.Role of oxidized low density lipoprotein in atherogenesisJ Clin Invest1991; 88: 1785–1792.
19.
Dieber-RothenederMPuhlHWaegHStrieglGEsterbauerH.Effect of oral supplementation with D-alpha-tocopherol on vitamin E content of human low density lipoproteins and resistance to oxidationJ Lipid Res1991; 32: 1325–1332.
20.
KeaneyJFGazianoJMXuAFreiBCurran-CelentanoJShwaeryGTLow-dose α-tocopherol improves and high-dose α-tocopherol worsens endothelial vasodilator function in cholesterol fed rabbitsJ Clin Invest1994; 93: 844–851.
21.
FaruqiRde la MottaCDiCorletoP.Alpha-tocopherol inhibits agonist-induced monocytic cell adhesion to cultured human endothelial cellsJ Clin Invest1994; 94: 592–600.
22.
NavabMImesSSHamaSYHoughGPRossLABorckRWMonocyte transmigration induced by modification of low density lipoprotein in cocultures of human aortic wall cells due to induction of monocyte chemotactic protein 1 synthesis and is abolished by high density lipoproteinJ Clin Invest1991; 88: 2039–2046.
23.
HennigBEnochCChowCK.Protection by vitamin E against endothelial cell injury by linoleic acid hydroperoxidesNutr Res1987; 7: 1253–1260.
24.
KeaneyJFGuoYCunninghamDShwaeryGTXuAVitaJA.Vascular incorporation of α-tocopherol prevents endothelial dysfunction due to oxidized LDL by inhibiting protein kinase C stimulationJ Clin Invest1996; 98: 386–394.
25.
TasinatoABoscoboinikDBartoliGMMaroniPAzziA.D-α-Tocopherol inhibition of vascular smooth muscle cell proliferation occurs at physiological concentrations, correlates with protein kinase C inhibition, and is independent of its antioxidant propertiesProc Natl Acad Sci USA1995; 92: 12190–12194.
26.
AzziABoscoboinikDMarilleyDÖzerNKStäubleBTasinatoA.Vitamin E: A sensor and an information transducer of the cell oxidation stateAm J Clin Nutr1995; 62 (suppl):1337S–1346S.
27.
HattoriYKasaiKBanbaNHattoriSNakamuraTShimodaS-l.Effect of a phorbol ester on immunoreactive endothelin-1 release from cultured porcine aortic endothelial cellsEndocrinol Japon1992; 39: 341–345.
28.
KitazumiKTasakaK.The role of c-June protein in thrombin-stimulated expression of preproendothelin-1 mRNA in porcine aortic endothelial cellsBiochem Pharmacol1996; 46: 455–464.
29.
PetersenG.A simplification of the protein assay method of Lowry which is more generally applicableAnal Biochem1977; 83: 346–356.
30.
HallerH.ZieglerWLindschauCLuftFCEndothelial cell tyrosine kinase receptor and G protein-coupled receptor activation involves distinct protein kinase C isoformsArterioscler Thromb Vasc Biol1993; 16: 678–686.
31.
MarsdenPABrennerBM.Transcriptional regulation of the endothelin-1 gene by TNF-αAm J Physiol1992; 262:C854–C861.
32.
EmoriTHirataYOhtaKShichiriMMarumoF.Secretory mechanisms of immunoreactive endothelin in cultured bovine endothelial cellsBiochem Biophys Res Commun1989; 160: 93–100.
33.
FreedmanJEFarhatJHLoscalzoJKeaneyJF.α-Tocopherol inhibits aggregation of human platelets by a protein kinase C-dependent mechanismCirculation1996; 94: 2434–2440.
34.
RicciarelliRTasinatoAClementSOzerNKBoscoboinikDAzziA.Alpha-tocopherol specifically inactivates cellular protein kinase C by changing its phosphorylation stateBiochem J1998; 334: 243–249.
35.
InoueAYanagisawaMTakuwaYMitsuiYKobayashiMMasakiT.The human preproendothelin-1 geneJ Biol Chem1989; 264: 14954–14959.
36.
TrejoJChambardJCKarinMBrownJH.Biphasic increase in c-jun mRNA is required for induction of AP-1 mediated gene transcription: Differential effects of muscarinic and thrombin receptor activationMol Cell Biol1992; 12: 4742–4750.
37.
BohmannDBosTJAdmonANishimuraTVogtPKTijanR.Human proto-oncogene c-jun encodes a DNA binding protein with structural and functional properties of transcription factor AP-1Science1987; 238: 1386–1392.
AzziABoscoboinikDFazzioAMarilleyDMaroniPOzerNKRRR-alpha-tocopherol regulation of gene transcription in response to the cell oxidant statusZ Ernahrungwiss1998; 37 (suppl 1): 21–28.
40.
PryorAWCornicelliJADevalLJTaitBTrivediBKWitiakDTA rapid screening test to determine the antioxidant potencies of natural and synthetic antioxidantsJ Org Chem1994; 58: 3521–3532.
41.
BierhausAChevionSChevionMHofmannMQueherbergerPIllmerTAdvanced glycation end product-induced activation of NF-kappaB is suppressed by alpha-lipoic acid in cultured endothelial cellsDiabetes1997; 46: 1481–1490.
42.
AnnatherDMillanMTPalmetshoferARobsonSCGeczyCRichieAJThrombin activates nuclear factor-Kappa B and potentiates endothelial cell activation by TNFJ Immunol1997; 159: 5620–5628.
43.
DasKCWhiteCW.Activation of NF-Kappa B by antineoplastic agents. Role of protein kinase CJ Biol Chem1997; 272: 14914–14920.
44.
SugiyamaSKugiyamaKOgataNDoiHOtaYOhgushiMBiphasic regulation of transcription factor nuclear factor kappa B activity in human endothelial cells by lysophosphatidyl choline through protein kinase C mediated pathwayArterioscler Thromb Vasc Biol1998; 18: 568–576.
45.
BarchowskyAMunroSRMoranaSJVincentiMPTreadwellM.Oxidant-sensitive and phosphorylation-dependent activation of NF-kappa B and AP-1 in endothelial cellsAm J Physiol1996; 269:L829–L836.
46.
SuzukiYJPackerLL.Inhibition of NF-kappa B binding activity by alpha-tocopheryl succinateBiochem Mol Biol Int1993; 4: 693–700.
47.
BoulangerCMTannerFCBeaMLHahnAWWernerALusherTF.Oxidized low density lipoproteins induce mRNA expression and release of endothelin from human and porcine endotheliumCirc Res1992; 70: 1191–1197.
48.
MaziereCAuclairMDjavaheri-MergnyMPackerLMaziereJC.Oxidized low-density lipoprotein induces activation of transcription factor NF-kappa B in fibroblasts endothelial and smooth muscle cellsBiochem Mol Biol Int1995; 39: 1201–1207.
49.
MaziereCDjavaheri-MergnyMFrey-FressartVDelattreJMaziereJC.Copper and cell-oxidized low-density lipoprotein induces activation protein 1 in fibroblasts, endothelial and smooth muscle cellsFEBS Lett1997; 409: 351–356.
50.
ChenTHTsenHPYangJYMaoSJ.Effect of antioxidant in endothelial cells exposed to oxidized low density lipoproteinsLife Sci1998; 62:PL277–PL282.
