Activation of the AMP-activated kinase by antidiabetes drug metformin stimulates nitric oxide synthesis in vivo by promoting the association of heat shock protein 90 and endothelial nitric oxide synthase
Activation of the AMP-activated kinase by antidiabetes drug metformin stimulates nitric oxide synthesis in vivo by promoting the association of heat shock protein 90 and endothelial nitric oxide synthase
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DOI：
10.2337/diabetes.55.02.06.db05-1064
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发表时间：
2006-02-01
期刊：
影响因子：
7.7
通讯作者：
Zou, MH
中科院分区：
文献类型：
--
作者：
Davis, BJ;Xie, ZL;Zou, MH
二甲双胍是治疗2型糖尿病最常用的药物之一，可改善血管内皮功能，减少2型糖尿病患者的心血管事件，但其机制尚不清楚。本研究旨在阐明二甲双胍如何改善内皮功能。培养的牛主动脉内皮细胞（BAEC）暴露于临床相关浓度的二甲双胍（50-500 μ mol/l）剂量依赖性增加丝氨酸-1179（Ser 1179）磷酸化（等同于人Ser 1179）的内皮型一氧化氮（NO）合酶（eNOS）以及其与热休克蛋白（hsp）-90，导致eNOS和NO生物活性（环GMP）的活化增加。二甲双胍的这些作用分别通过腺病毒过表达组成型活性W-AMIP激活激酶（AMPK）突变体或激酶失活的AWPK-alpha来模拟或完全消除。此外，二甲双胍和AMPK激动剂5-氨基咪唑-4-甲酰胺核苷的给药显著增加了野生型C57 BL 6小鼠中eNOS Ser 1179磷酸化、NO生物活性和eNOS与hsp 90的共免疫沉淀，但在AMPK-α 1敲除小鼠中没有，这表明AMPK是二甲双胍增强的eNOS体内激活所必需的。最后，BAEC与临床相关浓度的二甲双胍孵育显著减弱了高糖（30 mmol/l）诱导的hsp 90与eNOS相关性降低，这导致NO生物活性增加，粘附分子过表达减少，高糖暴露引起内皮细胞凋亡。总之，我们的研究结果表明，二甲双胍可能通过增加AMPK依赖性，热休克蛋白90介导的eNOS激活来改善糖尿病患者的血管内皮功能。
Metformin, one of most commonly used drugs for the treatment of type 2 diabetes, improves vascular endothelial functions and reduces cardiovascular events in patients with type 2 diabetes, although its mechanisms remain unknown. The current study aimed to elucidate how metformin improves endothelial functions. Exposure of cultured bovine aortic endothelial cells (BAECs) to clinically relevant concentrations of metformin (50-500 mu mol/l) dose-dependently increased serine-1179 (Ser1179) phosphorylation (equal to human Ser1179) of endothelial nitric oxide (NO) synthase (eNOS) as well as its association with heat shock protein (hsp)-90, resulting in increased activation of eNOS and NO bioactivity (cyclic GMP). These effects of metformin were mimicked or completely abrogated by adenoviral overexpression of a constitutively active W-AMIP-activated kinase (AMPK) mutant or a kinase-inactive AWPK-alpha, respectively. Furthermore, administration of metformin as well as 5-aminoimidazole-4-carboxamide ribonucleoside, an AMPK agonist, significantly increased eNOS Ser1179 phosphorylation, NO bioactivity, and coim munoprecipitation of eNOS with hsp90 in wild-type C57BL6 mice but not in AMPK-alpha 1 knockout mice, suggesting that AMPK is required for metformin-enhanced eNOS activation in vivo. Finally, incubation of BAECs with clinically relevant concentrations of metformin dramatically attenuated high-glucose (30 mmol/l)-induced reduction in the association of hsp90 with eNOS, which resulted in increased NO bioactivity with a reduction in overexpression of adhesion molecules and endothelial apoptosis caused by high-glucose exposure. Taken together, our results indicate that metformin might improve vascular endothelial functions in diabetes by increasing AMPK-dependent, hsp90-mediated eNOS activation.