Abstract
We revealed previously that nectandrin B isolated from Myristica fragrans (nutmeg, Myristicaceae) functions as a potent AMP-activated protein kinase (AMPK) activator and showed its antiobesity 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 AMPK, presumably via Ca2+/calmodulin 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 small interfering siRNA (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 PI3K. These results suggest that potent AMPK activator nectandrin B enhances NO production via eNOS phosphorylation in endothelial cells and ERα-dependent PI3K activity is required.
Footnotes
This work was supported by the National Research Foundation of Korea, funded by the Korean government [Grant 2010-0001707]; and the Ministry of Education Science and Technology of the Korean government [Post 21st Frontier Research Program Grant 2010-0026355].
Article, publication date, and citation information can be found at http://molpharm.aspetjournals.org.
doi:10.1124/mol.111.073502.
-
ABBREVIATIONS:
- eNOS
- endothelial nitric-oxide synthase
- AICAR
- 5-aminoimidazole-4-carboxamide-1-β-d-ribofuranoside
- AMPK
- AMP-activated protein kinase
- HUVEC
- human umbilical vein endothelial cell
- Akt
- protein kinase B
- ERK
- extracellular signal regulated kinase
- JNK
- c-Jun N-terminal kinase
- ER
- estrogen receptor
- ACC
- acetyl CoA carboxylase
- CaMK
- Ca2+/calmodulin-dependent protein kinase
- LY294002
- 2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
- PD98059
- 2′-amino-3′-methoxyflavone
- B203580
- 4-(4-fluorophenyl)-2-(4-methylsulfinylphenyl)-5-(4-pyridyl)1H-imidazole
- SP600125
- 1,9-pyrazoloanthrone
- ICI 182780
- fulvestrant
- A3281
- N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide hydrochloride
- PPT
- 4,4′,4″-(4-Propyl-[1H]-pyrazole-1,3,5-triyl)trisphenol
- DPN
- diarylpropionitrile
- MPP
- methyl-piperidino-pyrazole
- THC
- tetrahydrochrysene
- siRNA
- small interfering RNA
- DN
- dominant-negative
- CA
- constitutive active
- MTT
- 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide
- DAF-2 DA
- 4,5-diaminofluorescein diacetate
- TE
- Tris-EDTA
- PI3K
- phosphatidylinositol 3-kinase
- LKB
- liver kinase B1
- compound C
- 6-[4-(2-piperidin-1-yl-ethoxy)-phenyl)]-3-pyridin-4-yl-pyrrazolo[1,5-a]-pyrimidine.
- Received May 9, 2011.
- Accepted September 22, 2011.
- Copyright © 2011 The American Society for Pharmacology and Experimental Therapeutics
MolPharm articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|
