Acute activation and phosphorylation of endothelial nitric oxide synthase by HMG-CoA reductase inhibitors.
3-Hydroxy-3-methylglutaryl (HMG)-CoA reductase inhibitors, statins, provide beneficial effects independent of their lipid-lowering effects. One beneficial effect appears to involve acute activation of endothelial nitric oxide (NO) synthase (eNOS) and increased NO release. However, the mechanism of acute statin-stimulated eNOS activation is unknown. Therefore, we hypothesized that eNOS activation may be coupled to altered eNOS phosphorylation. Bovine aortic endothelial cells (BAECs), passages 2-6, were treated with either lovastatin or pravastatin from 0 to 30 min. eNOS phosphorylation was examined by Western blot by use of phosphospecific antibodies for Ser-1179, Ser-635, Ser-617, Thr-497, and Ser-116. Statin stimulation of BAECs increased eNOS phosphorylation at Ser-1179 and Ser-617, which was blocked by the phosphatidylinositol 3-kinase (PI3-kinase)/Akt inhibitor wortmannin, and at Ser-635, which was blocked by the protein kinase A (PKA) inhibitor KT-5720. Statin treatment of BAECs transiently increased NO release by fourfold, measured by cGMP accumulation, and was attenuated by N-nitro-l-arginine methyl ester, wortmannin, and KT-5720 but not by mevalonate. In conclusion, these data demonstrate that eNOS is acutely activated by statins independent of HMG-CoA reductase inhibition and that in addition to Ser-1179, eNOS phosphorylation at Ser-635 and Ser-617 through PKA and Akt, respectively, may explain, in part, a mechanism by which eNOS is activated in response to acute statin treatment.
Harris
M Brennan
MB
Department of Pediatrics, Medical College of Georgia, Augusta, Georgia 30912-2500, USA. mbharr@wm.edu
Blackstone
Michele A
MA
Sood
Sarika G
SG
Li
Chunying
C
Goolsby
Jonathan M
JM
Venema
Virginia J
VJ
Kemp
Bruce E
BE
Venema
Richard C
RC
D000818:Animals; D001011:Aorta; D002417:Cattle; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000201:enzymology* / Q000378:metabolism; D004789:Enzyme Activation; D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors / Q000494:pharmacology*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III
D019161:Hydroxymethylglutaryl-CoA Reductase Inhibitors; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III