Oleanolic acid induces relaxation and calcium-independent release of endothelium-derived nitric oxide
Oleanolic acid induces relaxation and calcium-independent release of endothelium-derived nitric oxide
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DOI：
10.1038/bjp.2008.289
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发表时间：
2008-10-01
影响因子：
7.3
通讯作者：
Simonsen, U.
中科院分区：
文献类型：
--
作者：
Rodriguez-Rodriguez, R.;Stankevicius, E.;Simonsen, U.
背景与目的：本研究探讨了齐墩果酸（橄榄油的一种成分）增加一氧化氮（NO）释放的机制。实验方法：测量大鼠离体肠系膜动脉的等长张力、一氧化氮浓度或内皮细胞钙。对人脐静脉内皮细胞（HUVECs）原代培养进行内皮细胞NOS （eNOS）和Akt激酶的免疫印迹检测。齐墩果酸（3-30 mM）引起去甲肾上腺素收缩大鼠肠系膜上动脉和小动脉内皮依赖性松弛。在大鼠肠系膜上动脉中，齐果酸诱导一氧化氮浓度同时升高和松弛，这些反应被一氧化氮抑制剂不对称二甲基精氨酸（300 mM）和一氧化氮清除剂氧合血红蛋白（10 mM）所抑制。齐墩果酸引起的NO增加在Ca2+游离溶液和内质网钙- atp酶抑制剂thapsigarin （1 mM）的存在下不减少。齐墩果酸引起舒张，内皮细胞钙含量无变化，但动脉段平滑肌钙含量降低。同果酸不能增加HUVECs中的钙，但增加了Akt激酶丝氨酸473位点（Akt- ser(473)）和eNOS丝氨酸（1177）位点（eNOS- ser(1177)）的时间依赖性磷酸化，磷酸化被磷酸肌醇-3激酶抑制剂减弱。结论和意义：本研究提供了直接证据，表明橄榄油的一种成分齐墩果酸可以激活内皮依赖性NO的释放，并降低平滑肌细胞钙，随后松弛。齐墩果酸诱导的内皮源性NO释放不依赖于内皮细胞钙，并涉及磷酸肌醇-3激酶依赖性Akt-Ser磷酸化（473）和eNOS-Ser磷酸化（1177）。
Background and purpose: The present study investigated the mechanisms by which oleanolic acid, a component of olive oil, increases release of nitric oxide (NO).Experimental approach: Measurements of isometric tension, NO concentration, or endothelial cell calcium were made in rat isolated mesenteric arteries. Immunoblotting for endothelial NOS (eNOS) and Akt kinase were performed in primary cultures of human umbilical vein endothelial cells (HUVECs).Key results: Oleanolic acid (3-30 mM) evoked endothelium-dependent relaxations in noradrenaline-contracted rat superior and small mesenteric arteries. In rat superior mesenteric arteries, oleanolic acid induced simultaneous increases in NO concentration and relaxation, and these responses were inhibited by an inhibitor of NOS, asymmetric dimethyl-L-arginine (300 mM) and by the NO scavenger, oxyhaemoglobin (10 mM). Oleanolic acid-evoked NO increases were not reduced in Ca2+ free solution and in the presence of an inhibitor of endoplasmic reticulum calcium-ATPase, thapsigargin ( 1 mM). Oleanolic acid evoked relaxation without changes in endothelial cell calcium, but decreased smooth muscle calcium in arterial segments. Oleanolic acid failed to increase calcium in HUVECs, but increased time-dependently phosphorylation of Akt kinase at Serine 473 (Akt-Ser(473)) and eNOS at Serine(1177) (eNOS-Ser(1177)), which was attenuated by inhibitors of phosphoinositide-3-kinase.Conclusions and implications: This study provides direct evidence that a component of olive oil, oleanolic acid, activated endothelium-dependent release of NO and decreased smooth muscle cell calcium followed by relaxation. The oleanolic acid-evoked endothelium-derived NO release was independent of endothelial cell calcium and involved phosphoinositide-3-kinasedependent phosphorylation of Akt-Ser(473) followed by phosphorylation of eNOS-Ser(1177).