表没食子儿茶素没食子酸酯通过靶向自噬依赖的PI3K-AKT-mTOR途径保护血管内皮细胞免受氧化应激诱导的损伤。

EGCG protects vascular endothelial cells from oxidative stress-induced damage by targeting the autophagy-dependent PI3K-AKT-mTOR pathway.

作者信息

Meng Jiao, Chen Yuhua, Wang Junzhe, Qiu Junling, Chang Cuicui, Bi Fangfang, Wu Xiaopeng, Liu Wei

机构信息

Central Laboratory of Medicine School, Xi'an Peihua University, Xi'an 710100, China.

Department of Medical Science Research Center, Shaanxi Fourth People's Hospital, Xi'an 710143, China.

出版信息

Ann Transl Med. 2020 Mar;8(5):200. doi: 10.21037/atm.2020.01.92.

BACKGROUND

Autophagy plays an important role in cellular homeostasis. Epigallocatechin gallate (EGCG), a polyphenol derived from green tea, has been shown to elicit vascular protective effects. Our study aimed to investigate the protective effect of EGCG in an endothelial injury model induced by hydrogen peroxide (HO) and reveal the possible mechanisms.

METHODS

Human vascular endothelial cells (HUVECs) were pretreatment with different concentration of EGCG, then exposed to HO. Cell viability was measured with MTS assay. Apoptosis was evaluated with TUNEL staining and apoptosis-related protein was determined by western blot. Autophagy flux was assessed by transmission electron microscopy and LC3 plasmid transfection. Besides, the role mTOR in EGCG-mediated antioxidant responses was validated with siRNA transfection.

RESULTS

The results showed that pretreatment with EGCG significantly improved the survival of HUVECs from HO-induced cell death. After exposed to HO, EGCG upregulated the levels of Atg5, Atg7, LC3 II/I, and the Atg5-Atg12 complex in HUVECs, while downregulated apoptosis-related protein. Besides, EGCG inhibited the PI3K-AKT-mTOR signaling pathway. Knockdown of mTOR partially promoted EGCG-induced autophagy.

CONCLUSIONS

These results suggest that EGCG induces autophagy by targeting the mTOR pathway, indicating that EGCG has the potential to prevent and treat oxidative stress-related cardiovascular diseases.

背景

自噬在细胞稳态中起重要作用。表没食子儿茶素没食子酸酯（EGCG）是一种从绿茶中提取的多酚，已被证明具有血管保护作用。我们的研究旨在探讨EGCG在过氧化氢（HO）诱导的内皮损伤模型中的保护作用，并揭示其可能的机制。

方法

用人血管内皮细胞（HUVECs）进行不同浓度EGCG预处理，然后暴露于HO。用MTS法测定细胞活力。用TUNEL染色评估细胞凋亡，并用蛋白质印迹法测定凋亡相关蛋白。通过透射电子显微镜和LC3质粒转染评估自噬通量。此外，用小干扰RNA（siRNA）转染验证mTOR在EGCG介导的抗氧化反应中的作用。

结果

结果表明，EGCG预处理显著提高了HUVECs在HO诱导的细胞死亡中的存活率。暴露于HO后，EGCG上调了HUVECs中Atg5、Atg7、LC3 II/I和Atg5-Atg12复合物的水平，同时下调了凋亡相关蛋白。此外，EGCG抑制了PI3K-AKT-mTOR信号通路。敲低mTOR部分促进了EGCG诱导的自噬。