State Key Laboratory of Drug Research, The National Center for Drug Screening, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 201203, Shanghai, China.
University of Chinese Academy of Sciences, 100049, Beijing, China.
Acta Pharmacol Sin. 2019 Jul;40(7):908-918. doi: 10.1038/s41401-018-0193-5. Epub 2018 Dec 18.
Palmitate (PA) exposure induces stress conditions featuring ROS accumulation and upregulation of p62 expression, resulting in autophagic flux blockage and cell apoptosis. Sulfuretin (Sul) is a natural product isolated from Rhus verniciflua Stokes; the cytoprotective effect of Sul on human hepatic L02 cells and mouse primary hepatocytes under PA-induced stress conditions was investigated in this study. Sul induced mitophagy by activation of p-TBK1 and LC3 and produced a concomitant decline in p62 expression. Autophagosome formation and mitophagy were assessed by the sensitive dual fluorescence reporter mCherry-EGFP-LC3B, and mitochondrial fragmentation was analyzed using MitoTracker Deep Red FM. A preliminary structure-activity relationship (SAR) for Sul was also investigated, and the phenolic hydroxyl group was found to be pivotal for maintaining the cytoprotective bioactivity of Sul. Furthermore, experiments using flow cytometry and western blots revealed that Sul reversed the cytotoxic effect stimulated by the autophagy inhibitors 3-methyladenine (3-MA) and chloroquine (CQ), and its cytoprotective effect was almost eliminated when the autophagy-related 5 (Atg5) gene was knocked down. These studies suggest that, in addition to its antioxidative effects, Sul stimulates mitophagy and restores impaired autophagic flux, thus protecting hepatic cells from apoptosis, and that Sul has potential future medical applications for hepatoprotection.
棕榈酸（PA）暴露会引起应激状态，导致 ROS 积累和 p62 表达上调，从而阻断自噬流并诱导细胞凋亡。二氢杨梅素（Sul）是从漆树科盐肤木中分离得到的天然产物，本研究旨在探讨 Sul 在 PA 诱导的应激条件下对人肝 L02 细胞和小鼠原代肝细胞的细胞保护作用。Sul 通过激活 p-TBK1 和 LC3 诱导细胞自噬，并伴随着 p62 表达的下降。通过 mCherry-EGFP-LC3B 敏感双荧光报告检测自噬体形成和细胞自噬，使用 MitoTracker Deep Red FM 分析线粒体片段化。还对 Sul 的初步构效关系（SAR）进行了研究，发现酚羟基对于维持 Sul 的细胞保护生物活性至关重要。此外，使用流式细胞术和 Western blot 实验表明，Sul 逆转了自噬抑制剂 3-甲基腺嘌呤（3-MA）和氯喹（CQ）刺激的细胞毒性作用，当自噬相关 5（Atg5）基因被敲低时，Sul 的细胞保护作用几乎被消除。这些研究表明，除了抗氧化作用外，Sul 还能刺激细胞自噬和恢复受损的自噬流，从而保护肝细胞免于凋亡，并且 Sul 在肝保护方面具有潜在的医学应用前景。
