Cardioprotection by resveratrol: a novel mechanism via autophagy involving the mTORC2 pathway
Cardioprotection by resveratrol: a novel mechanism via autophagy involving the mTORC2 pathway
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DOI：
10.1093/cvr/cvp384
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发表时间：
2010-04-01
影响因子：
10.8
通讯作者：
Das, Dipak K.
中科院分区：
文献类型：
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作者：
Gurusamy, Narasimman;Lekli, Istvan;Das, Dipak K.
根据我们之前的报道，即缺血预适应诱导的心脏保护作用会诱导自噬，并且白藜芦醇（一种存在于葡萄和红酒中的多酚抗氧化剂）会诱导预适应样作用，我们试图确定白藜芦醇是否可以诱导自噬。较低剂量的白藜芦醇（H9c2 心肌成肌细胞中为 0.1 和 1 μM，2.5 mg/kg/天（大鼠））诱导心脏自噬，表现为缺氧-复氧或缺血-再灌注后自噬体及其成分 LC3-II 的形成增强。高剂量的白藜芦醇会减弱自噬。自噬的诱导与细胞存活率的提高和细胞凋亡的减少相关。与单独使用白藜芦醇相比，用雷帕霉素（100 nM）（一种已知的自噬诱导剂）治疗并没有进一步增加自噬。自噬抑制剂渥曼青霉素 (2 μM) 和 3-甲基腺嘌呤 (10 mM) 可显着减弱白藜芦醇诱导的自噬并诱导细胞死亡。低剂量白藜芦醇对哺乳动物雷帕霉素靶点（mTOR）的激活有差异性调节，即mTOR丝氨酸2448处的磷酸化受到抑制，而mTOR丝氨酸2481处的磷酸化增加，而较高剂量的白藜芦醇则减弱这种磷酸化。尽管白藜芦醇减弱了 mTOR 复合物 1 的激活，但低剂量白藜芦醇显着诱导 Rictor（mTOR 复合物 2 的组成部分）的表达，并激活其下游生存激酶 Akt（Ser 473）。发现白藜芦醇诱导的 Rictor 与 mTOR 结合。此外，Rictor siRNA 治疗减弱了白藜芦醇诱导的自噬。我们的结果表明，在较低剂量下，白藜芦醇介导的细胞存活部分是通过涉及 mTOR-Rictor 存活途径的自噬诱导介导的。
On the basis of our previous reports that cardioprotection induced by ischaemic preconditioning induces autophagy and that resveratrol, a polyphenolic antioxidant present in grapes and red wine induces preconditioning-like effects, we sought to determine if resveratrol could induce autophagy.Resveratrol at lower doses (0.1 and 1 mu M in H9c2 cardiac myoblast cells and 2.5 mg/kg/day in rats) induced cardiac autophagy shown by enhanced formation of autophagosomes and its component LC3-II after hypoxia-reoxygenation or ischaemia-reperfusion. The autophagy was attenuated with the higher dose of resveratrol. The induction of autophagy was correlated with enhanced cell survival and decreased apoptosis. Treatment with rapamycin (100 nM), a known inducer of autophagy, did not further increase autophagy compared with resveratrol alone. Autophagic inhibitors, wortmannin (2 mu M) and 3-methyladenine (10 mM), significantly attenuated the resveratrol-induced autophagy and induced cell death. The activation of mammalian target of rapamycin (mTOR) was differentially regulated by low-dose resveratrol, i.e. the phosphorylation of mTOR at serine 2448 was inhibited, whereas the phosphorylation of mTOR at serine 2481 was increased, which was attenuated with a higher dose of resveratrol. Although resveratrol attenuated the activation of mTOR complex 1, low-dose resveratrol significantly induced the expression of Rictor, a component of mTOR complex 2, and activated its downstream survival kinase Akt (Ser 473). Resveratrol-induced Rictor was found to bind with mTOR. Furthermore, treatment with Rictor siRNA attenuated the resveratrol-induced autophagy.Our results indicate that at lower dose, resveratrol-mediated cell survival is, in part, mediated through the induction of autophagy involving the mTOR-Rictor survival pathway.