BK21 Project Team, College of Pharmacy, Chosun University, Gwangju, Republic of Korea.
Biochem Pharmacol. 2012 Dec 1;84(11):1437-50. doi: 10.1016/j.bcp.2012.09.004. Epub 2012 Sep 13.
Endothelial nitric oxide synthase (eNOS) has important regulatory functions in vascular tone, and impaired endothelium-dependent vasodilatation is a key event in diabetes and atherosclerosis. Vitis amurensis grapes containing resveratrol oligomers are consumed as wine and fruit and have antioxidative and neuroprotective effects. In this study, our goal was identify the most potent eNOS-activating compound among six stilbenes and oligostilbenes found in V. amurensis and to clarify its molecular mechanism. Among the six tested compounds, amurensin G most potently relaxed endothelium-intact aortic rings and increased eNOS phosphorylation and nitric oxide (NO) production. Amurensin G increased both estrogen receptor (ER) phosphorylation and ER-dependent gene transcription, and ERα or ERβ inhibition suppressed amurensin G-mediated eNOS phosphorylation. Amurensin G enhanced the activities of phosphatidylinositol 3-kinase (PI3K) and Src and their chemical inhibitors suppressed amurensin G-stimulated eNOS phosphorylation. Moreover, amurensin G activated AMP-activated protein kinase (AMPK), and amurensin G-stimulated eNOS phosphorylation and PI3K activation were reversed by AMPK inhibition. ER inhibition reversed AMPK-dependent PI3K activation in response to amurensin G. Amurensin G-mediated endothelium-dependent relaxation was blocked by inhibition of AMPK, ER, Src, or PI3K. These results suggest that amurensin G enhances NO production via eNOS phosphorylation in endothelial cells, and ER-dependent AMPK/PI3K pathways are required. Amurensin G would be applicable to prevent atherosclerosis.
内皮型一氧化氮合酶（eNOS）在血管张力中具有重要的调节功能，而内皮依赖性血管舒张功能受损是糖尿病和动脉粥样硬化的关键事件。含有白藜芦醇低聚物的山葡萄被作为葡萄酒和水果食用，具有抗氧化和神经保护作用。在这项研究中，我们的目标是确定在山葡萄中发现的六种芪类和寡芪类化合物中最有效的 eNOS 激活化合物，并阐明其分子机制。在测试的六种化合物中，虎杖素 G 最有效地松弛了完整内皮的主动脉环，并增加了 eNOS 磷酸化和一氧化氮（NO）的产生。虎杖素 G 增加了雌激素受体（ER）的磷酸化和 ER 依赖性基因转录，而 ERα或 ERβ抑制则抑制了虎杖素 G 介导的 eNOS 磷酸化。虎杖素 G 增强了磷脂酰肌醇 3-激酶（PI3K）和Src 的活性，其化学抑制剂抑制了虎杖素 G 刺激的 eNOS 磷酸化。此外，虎杖素 G 激活了 AMP 激活的蛋白激酶（AMPK），而 AMPK 抑制则逆转了虎杖素 G 刺激的 eNOS 磷酸化和 PI3K 激活。ER 抑制逆转了虎杖素 G 刺激的 AMPK 依赖性 PI3K 激活。虎杖素 G 介导的内皮依赖性松弛被 AMPK、ER、Src 或 PI3K 的抑制所阻断。这些结果表明，虎杖素 G 通过内皮细胞中 eNOS 的磷酸化增强了 NO 的产生，而 ER 依赖性 AMPK/PI3K 途径是必需的。虎杖素 G 可用于预防动脉粥样硬化。
