Scutellarin's Cardiovascular Endothelium Protective Mechanism: Important Role of PKG-Iα.
Scutellarin's Cardiovascular Endothelium Protective Mechanism: Important Role of PKG-Iα.
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灯盏乙素的心血管内皮保护机制：PKG-Ialpha 的重要作用。
DOI：
10.1371/journal.pone.0139570
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发表时间：
2015
期刊：
影响因子：
3.7
通讯作者：
Yang W
中科院分区：
文献类型：
--
作者：
Li L;Li L;Chen C;Yang J;Li J;Hu N;Li Y;Zhang D;Guo T;Liu X;Yang W
灯盏乙素（SCU）是一种黄酮苷类化合物，在我国已成功应用于临床治疗缺血性疾病。本实验观察了SCU对在体心肌缺血再灌注（MIR）损伤时冠状动脉（CA）内皮功能障碍（艾德）的影响。利用体外培养的内皮细胞缺氧/复氧（HR）损伤进一步研究PKG-Iα的参与。在大鼠MIR模型中，SCU（45和90 mg/kg，iv）显著减少缺血面积，恢复离体CA环的内皮依赖性血管舒张功能。PKG抑制剂Rp-8-Br-cGMP（50 μg/kg，iv）可减轻SCU的保护作用。在SCU处理动物的心脏组织和血清中均观察到血管舒张剂刺激的磷蛋白（VASP）（PKG的主要底物）在Ser 239处的磷酸化增加。在培养的人心脏微血管内皮细胞（HCMEC）中，SCU（1和10 μM）剂量依赖性地保护细胞活力，并增加PKG-Iα的mRNA和蛋白水平，对抗HR损伤。SCU处理后PKG活性也明显升高。然后使用靶向蛋白质组学分析（MRM-MS）研究PKG-1α的活化，检查自磷酸化结构域（aa 42 -94）的磷酸化状态。HR损伤后PKG-Iα的Ser 50、Ser 72、Ser 89磷酸化水平明显降低，而SCU处理后PKG-Iα的Ser 50、Ser 72、Ser 89磷酸化水平明显升高，同时还增加了Ser 44和Thr 58两个新的磷酸化位点。提示PKG-Iα可能在SCU对艾德抗MIR损伤的保护作用中起重要作用。
Scutellarin (SCU), a flavonoid glycoside compound, has been successfully used in clinic for treatment of ischemic diseases in China. In this report, we checked the effects of SCU on endothelium dysfunction (ED) of coronary artery (CA) against myocardial ischemia reperfusion (MIR) injury in vivo. The involvement of PKG-Iα was further studied using cultured endothelial cells subjected to hypoxia reoxygenation (HR) injury in vitro. In rat MIR model, SCU (45 and 90 mg/kg, iv) significantly reduced ischemic size and restored the endothelium-dependent vasodilation of isolated CA rings. PKG inhibitor Rp-8-Br-cGMP (50 μg/kg, iv) could ameliorate the protective effects of SCU. Increase in phosphorylation of vasodilator-stimulated phosphoprotein (VASP), a main substrate of PKG, at Ser 239 was observed in both heart tissue and serum of SCU-treated animals. In cultured human cardiac microvascular endothelial cells (HCMECs), SCU (1 and 10 μM) dose-dependently protected cell viability and increased the mRNA and protein level of PKG-Iα against HR injury. The activity of PKG was also increased by SCU treatment. The activation of PKG–1α was then studied using targeted proteomic analysis (MRM-MS) checking the phosphorylation state of the autophosphorylation domain (aa42-94). Significant decrease in phosphorylation of PKG-Iα at Ser50, Ser72, Ser89 was induced by HR injury while SCU treatment significantly increased the phosphorylation of PKG-Iα, not only at Ser50, Ser72 and Ser89, but also at Ser44 and Thr58 (two novel phosphorylation domains). Our results demonstrate PKG-Iα might play an important role in the protective effects of SCU on ED against MIR injury.