RT Journal Article SR Electronic T1 Nectandrin B Activates eNOS Phosphorylation in Endothelial Cells: Role of the AMP-activated Protein Kinase/estrogen Receptor α/phosphatidylinositol 3-kinase/Akt Pathway JF Molecular Pharmacology JO Mol Pharmacol FD American Society for Pharmacology and Experimental Therapeutics SP mol.111.073502 DO 10.1124/mol.111.073502 A1 Tran T Hien A1 Won Keun Oh A1 Nguyen P Hung A1 Seok Jeong Oh A1 Moo Yeol Lee A1 Keon Wook Kang YR 2011 UL http://molpharm.aspetjournals.org/content/early/2011/09/22/mol.111.073502.abstract AB We previously revealed that nectandrin B isolated from Myristica fragrans (nutmeg, Myristicaceae) functions as a potent AMP-activated protein kinase (AMPK) activator and showed its anti-obesity effect. In this study, we investigated whether nectandrin B affects phosphorylation of endothelial nitric oxide synthase (eNOS) in human endothelial cells. Nectandrin B increased the phosphorylation of eNOS and nitric oxide (NO) production in a concentration dependent manner and maximal effect was found at 10 μg/ml. Nectandrin B activates AMP-activated protein kinase (AMPK) presumably via CaM kinase II activation and nectandrin B-stimulated eNOS phosphorylation was reversed by AMPK inhibition. Both the enzyme activity of phosphatidylinositol 3-kinase (PI3K) and the estrogen receptor (ER)-dependent reporter gene transcription were enhanced by nectandrin B. ERα inhibition by specific antagonist or siRNA suppressed nectandrin B-mediated eNOS phosphorylation. Moreover, AMPK inhibition significantly reversed the activation of ER-dependent transcription and PI3K activation in response to nectandrin B. Nectandrin B evoked endothelium-dependent relaxation in rat aortic rings and this was blocked by inhibition of AMPK, ER or PI3-kinase. These results suggest that potent AMPK activator, nectandrin B enhances NO production via eNOS phosphorylation in endothelial cells and ERα-dependent PI3-kinase activity is required.