(-)-epicatechin activation of endothelial cell endothelial nitric oxide synthase, nitric oxide, and related signaling pathways.
Recent reports indicate that (-)-epicatechin can exert cardioprotective actions, which may involve endothelial nitric oxide synthase (eNOS)-mediated nitric oxide production in endothelial cells. However, the mechanism by which (-)-epicatechin activates eNOS remains unclear. In this study, we proposed to identify the intracellular pathways involved in (-)-epicatechin-induced effects on eNOS, using human coronary artery endothelial cells in culture. Treatment of cells with (-)-epicatechin led to time- and dose-dependent effects that peaked at 10 minutes at 1 mumol/L. (-)-Epicatechin treatment activates eNOS via serine 633 and serine 1177 phosphorylation and threonine 495 dephosphorylation. Using specific inhibitors, we have established the participation of the phosphatidylinositol 3-kinase pathway in eNOS activation. (-)-Epicatechin induces eNOS uncoupling from caveolin-1 and its association with calmodulin-1, suggesting the involvement of intracellular calcium. These results allowed us to propose that (-)-epicatechin effects may be dependent on actions exerted at the cell membrane level. To test this hypothesis, cells were treated with the phospholipase C inhibitor U73122, which blocked (-)-epicatechin-induced eNOS activation. We also demonstrated inositol phosphate accumulation in (-)-epicatechin-treated cells. The inhibitory effects of the preincubation of cells with the calmodulin-dependent kinase II (CaMKII) inhibitor KN-93 indicate that (-)-epicatechin-induced eNOS activation is at least partially mediated via the Ca(2+)/CaMKII pathway. The (-)-epicatechin stereoisomer catechin was only partially able to stimulate nitric oxide production in cells. Together, these results strongly suggest the presence of a cell surface acceptor-effector for the cacao flavanol (-)-epicatechin, which may mediate its cardiovascular effects.
Ramirez-Sanchez
Israel
I
Department of Medicine, University of California, San Diego, Calif, USA.
Maya
Lisandro
L
Ceballos
Guillermo
G
Villarreal
Francisco
F
D000328:Adult; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000378:metabolism; D002392:Catechin / Q000378:metabolism / Q000494:pharmacology*; D022461:Caveolins / Q000378:metabolism; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000166:cytology; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000187:drug effects / Q000378:metabolism*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D011336:Probability; D012016:Reference Values; D012494:Sampling Studies; D015398:Signal Transduction / Q000187:drug effects
D022461:Caveolins; D009569:Nitric Oxide; D002392:Catechin; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases
Cardiovasc Res. 1999 Aug 15;43(3):532-41
10690325
J Mol Cell Cardiol. 2007 Feb;42(2):271-9
16839566
Basic Res Cardiol. 2009 Jan;104(1):100-10
19101751
Can J Cardiol. 2009 Jun;25(6):e195-202
19536390
J Hypertens. 2007 Mar;25(3):541-9
17278969
FASEB J. 2006 Aug;20(10):1742-4
16790523
J Agric Food Chem. 2009 Jul 22;57(14):6156-62
19537788
J Am Coll Cardiol. 2010 Jun 22;55(25):2869-76
20579545
Mol Pharmacol. 2004 Nov;66(5):1310-6
15304551
Int Immunopharmacol. 2002 Dec;2(13-14):1755-62
12489789
Circulation. 2009 Mar 17;119(10):1433-41
19289648
Endocr Rev. 2002 Oct;23(5):665-86
12372846
Mol Nutr Food Res. 2009 Mar;53(3):322-31
19051188
J Biol Chem. 2001 May 11;276(19):16587-91
11340086
J Pharmacol Exp Ther. 2006 Jul;318(1):238-45
16574779
Kidney Int. 2005 May;67(5):1654-8
15840005
Arch Pharm Res. 2009 Aug;32(8):1103-8
19727602
Nitric Oxide. 2009 Sep;21(2):77-91
19497380
Ophthalmologica. 2001 Jul-Aug;215(4):303-8
11399940
Eur J Clin Nutr. 1999 Jan;53(1):22-6
10048796
Proc Natl Acad Sci U S A. 2006 Jan 24;103(4):1024-9
16418281
Circ Res. 2001 Jun 8;88(11):E68-75
11397791
J Nutr. 2000 Aug;130(8S Suppl):2109S-14S
10917931
Am J Physiol Heart Circ Physiol. 2008 Aug;295(2):H761-7
18567705