Autophagic effects of Hibiscus sabdariffa leaf polyphenols and epicatechin gallate (ECG) against oxidized LDL-induced injury of human endothelial cells
Autophagic effects of Hibiscus sabdariffa leaf polyphenols and epicatechin gallate (ECG) against oxidized LDL-induced injury of human endothelial cells
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DOI：
10.1007/s00394-016-1239-4
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发表时间：
2017-08-01
影响因子：
5
通讯作者：
Lin, Hui-Hsuan
中科院分区：
文献类型：
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作者：
Chen, Jing-Hsien;Lee, Ming-Shih;Lin, Hui-Hsuan
目的氧化低密度脂蛋白（ox-LDL）通过促进血管内皮细胞损伤参与动脉粥样硬化的发病机制。木芙蓉叶多酚（HLP）富含黄酮类化合物，具有抗氧化和抗动脉粥样硬化活性。在这项研究中，我们检测了HLP及其主要化合物(-)-表儿茶素没食子酸酯（ECG）对体外暴露于oxLDL的人脐静脉内皮细胞（HUVECs）的保护作用。方法建立ox- ldl损伤HUVECs模型，检测细胞活力、细胞毒性、细胞增殖、细胞凋亡和自噬的变化。采用Western blotting、real-time PCR等方法检测HLP和ECG抗凋亡作用的机制。结果HLP或ECG均可提高ox- ldl诱导HUVECs生存能力丧失的存活率。此外，HLP或ECG显示减少ox- ldl依赖性细胞凋亡的潜力。然后，通过HLP或ECG增加ox- ldl诱导的酸性囊泡细胞器的形成和自噬相关基因的上调。在自噬抑制剂氯喹预处理下，LC3-II水平升高，进一步证实了hlp触发的自噬通量。分子数据表明，HLP或ECG的自噬作用可能通过III类PI3K/Beclin-1和PTEN/ I类PI3K/Akt级联信号介导，如使用III类PI3K抑制剂3-甲基ladenine （3-MA）和PTEN抑制剂SF1670。结论：我们的数据表明，富含ecg的HLP上调自噬途径，从而减少ox- ldl诱导的HUVECs损伤和凋亡，并为其抗动脉粥样硬化活性提供了新的机制。
Purpose Oxidized low-density lipoprotein (ox-LDL) contributes to the pathogenesis of atherosclerosis by promoting vascular endothelial cell injury. Hibiscus sabdariffa leaf polyphenols (HLP), rich in flavonoids, have been shown to possess antioxidant and antiatherosclerotic activities. In this study, we examined the protective role of HLP and its main compound (-)-epicatechin gallate (ECG) in human umbilical vein endothelial cells (HUVECs) exposed to oxLDL in vitro.Methods In a model of ox-LDL-impaired HUVECs, assessments of cell viability, cytotoxicity, cell proliferation, apoptosis, and autophagy were detected. To highlight the mechanisms of the antiapoptotic effects of HLP and ECG, the expressions of molecular proteins were measured by Western blotting, real-time PCR, and so on.Results HLP or ECG improved the survival of HUVECs from ox-LDL-induced viability loss. In addition, HLP or ECG showed potential in reducing ox-LDL-dependent apoptosis. Next, the ox-LDL-induced formation of acidic vesicular organelles and upregulation of the autophagy-related genes were increased by HLP or ECG. The HLP-triggered autophagic flux was further confirmed by increasing the LC3-II level under the pretreatment of an autophagy inhibitor chloroquine. Molecular data indicated the autophagic effect of HLP or ECG might be mediated via class III PI3K/Beclin-1 and PTEN/class I PI3K/Akt cascade signaling, as demonstrated by the usage of a class III PI3K inhibitor 3-methyladenine (3-MA) and a PTEN inhibitor SF1670.Conclusions Our data imply that ECG-enriched HLP upregulates the autophagic pathway, which in turn led to reduce ox-LDL-induced HUVECs injury and apoptosis and provide a new mechanism for its antiatherosclerotic activity.