Regulation of Rac1 by Simvastatin in Endothelial Cells DIFFERENTIAL ROLES OF AMP-ACTIVATED PROTEIN KINASE AND CALMODULIN-DEPENDENT KINASE KINASE-β
Regulation of Rac1 by Simvastatin in Endothelial Cells DIFFERENTIAL ROLES OF AMP-ACTIVATED PROTEIN KINASE AND CALMODULIN-DEPENDENT KINASE KINASE-β
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DOI：
10.1074/jbc.m808664200
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发表时间：
2009-05-29
影响因子：
4.8
通讯作者：
Michel, Thomas
中科院分区：
文献类型：
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作者：
Kou, Ruqin;Sartoretto, Juliano;Michel, Thomas
这些研究探讨了辛伐他汀、Rac1和amp活化蛋白激酶（AMPK）途径在培养的血管内皮细胞和他汀治疗小鼠的动脉制剂中的联系。他汀类药物除了对脂蛋白代谢的显著作用外，还可以调节小GTPase Rac1，并可能影响普遍存在的AMPK的磷酸化。我们在他汀治疗小鼠的动脉制剂和培养的内皮细胞中探索了他汀调节的Rac1和AMPK激活的途径。我们每天用辛伐他汀治疗成年小鼠2周，然后收集并分析动脉制剂。与对照动物相比，辛伐他汀治疗小鼠导致AMPK和LKB1磷酸化显著增加，蛋白激酶a活性降低，与Rac1激活显著增加相关。牛主动脉内皮细胞暴露于辛伐他汀24小时显著增加gtp结合的Rac1，并导致AMPK和AMPK激酶LKB1磷酸化增加。对辛伐他汀的这些反应被甲羟戊酸或焦磷酸香叶基阻断，而焦磷酸法尼基则不被阻断。小干扰RNA （siRNA）介导的AMPK敲低消除了辛伐他汀诱导的Rac1激活和LKB1磷酸化。重要的是，sirna介导的关键AMPK激酶（钙/钙调素依赖性蛋白激酶β）的敲低完全阻断了辛伐他汀诱导的内皮细胞迁移，也消除了他汀促进的AMPK和LKB1的磷酸化，特异性钙/钙调素依赖性蛋白激酶β抑制剂STO-609的药理抑制也是如此。此外，sirna介导的敲低Rac1完全阻断了辛伐他汀诱导的LKB1磷酸化，但不影响辛伐他汀诱导的AMPK磷酸化。这些发现确立了辛伐他汀在激活一种新的依赖于rac1的血管壁信号通路中的关键作用。
These studies explore the connections between simvastatin, Rac1, and AMP-activated protein kinase (AMPK) pathways in cultured vascular endothelial cells and in arterial preparations isolated from statin-treated mice. In addition to their prominent effects on lipoprotein metabolism, statins can regulate the small GTPase Rac1, and may also affect the phosphorylation of the ubiquitous AMPK. We explored pathways of statin-modulated Rac1 and AMPK activation both in arterial preparations from statin-treated mice as well as in cultured endothelial cells. We treated adult mice with simvastatin daily for 2 weeks and then harvested and analyzed arterial preparations. Simvastatin treatment of mice led to a significant increase in AMPK and LKB1 phosphorylation and to a decrease in protein kinase A activity relative to control animals, associated with a marked increase in Rac1 activation. Exposure of bovine aortic endothelial cells to simvastatin for 24 h strikingly increased GTP-bound Rac1 and led to increased phosphorylation of AMPK as well as the AMPK kinase LKB1. These responses to simvastatin were blocked by mevalonate or geranylgeranyl pyrophosphate but not by farnesyl pyrophosphate. Small interfering RNA (siRNA)mediated knockdown of AMPK abrogated simvastatin-induced Rac1 activation and LKB1 phosphorylation. Importantly, siRNA-mediated knockdown of the key AMPK kinase, calcium/calmodulin-dependent protein kinase kinase beta, completely blocked simvastatin-induced endothelial cell migration and also abrogated statin-promoted phosphorylation of AMPK and LKB1, as did pharmacological inhibition with the specific calcium/calmodulin-dependent protein kinase beta, inhibitor STO-609. Moreover, siRNA-mediated knockdown of Rac1 completely blocked simvastatin-induced LKB1 phosphorylation, but without affecting simvastatin-induced AMPK phosphorylation. These findings establish a key role for simvastatin in activation of a novel Rac1-dependent signaling pathway in the vascular wall.