School of Pharmacy, Department of Pharmacology, China Medical University, Shenyang, Liaoning, China.
Liaoning Key Laboratory of Molecular Targeted Anti-Tumor Drug Development and Evaluation, Shenyang, Liaoning, China.
Mol Nutr Food Res. 2018 Apr;62(8):e1700890. doi: 10.1002/mnfr.201700890. Epub 2018 Mar 23.
We investigated the role of endoplasmic reticulum (ER) stress in the protective effects of EGCG against the neuronal apoptosis in Aβ -induced SH-SY5Y cells and APP/PS1 transgenic mice.
Cell viability (CCK8 assay), flow cytometry, Hoechst 33258 staining, immunohistochemistry, transmission electron microscopy (TEM), and western blotting were used. EGCG prevented Aβ1-42-induced toxicity in SH-SY5Y cells, increased cell viability, and decreased apoptosis in a dose-dependent manner. In a subsequent mechanism study, it was found that this effect contributed to the down-regulation of GRP78, CHOP, cleaved-caspase-12 and -3. Moreover, EGCG also reduced the cytotoxicity induced by tunicamycin (TM) and thapsigargin (TG), two ER stress activators. Consistent with the in vitro study, EGCG inhibited neuronal apoptosis in the cortex of APP/PS1 transgenic mice, with the mitigation of ER abnormal ultrastructural swelling and the downregulation of ER-stress-associated proteins.
These results indicate that EGCG attenuates the neurotoxicity in Alzheimer's disease (AD) via a novel mechanism that involves inhibition of ER-stress-associated neuronal apoptosis in vitro and in vivo, suggesting the tremendous potential of EGCG for use in a nutritional preventive strategy against AD.
我们研究了内质网（ER）应激在 EGCG 对抗 Aβ诱导的 SH-SY5Y 细胞和 APP/PS1 转基因小鼠神经元凋亡中的保护作用中的作用。
使用细胞活力（CCK8 测定）、流式细胞术、Hoechst 33258 染色、免疫组织化学、透射电子显微镜（TEM）和蛋白质印迹法。EGCG 可预防 Aβ1-42 在 SH-SY5Y 细胞中的毒性，以剂量依赖性方式增加细胞活力并降低细胞凋亡。在随后的机制研究中，发现这种作用有助于下调 GRP78、CHOP、裂解 caspase-12 和 -3。此外，EGCG 还降低了两种内质网应激激活剂衣霉素（TM）和他普西琼（TG）诱导的细胞毒性。与体外研究一致，EGCG 抑制了 APP/PS1 转基因小鼠皮质中的神经元凋亡，减轻了内质网异常超微肿胀，并下调了内质网应激相关蛋白。
这些结果表明，EGCG 通过一种新的机制减轻阿尔茨海默病（AD）中的神经毒性，该机制涉及体外和体内抑制与内质网应激相关的神经元凋亡，这表明 EGCG 在用于 AD 的营养预防策略中有巨大的潜力。
