College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea; National Development Institute of Korean Medicine, Jangheung, Jeollanam-do 59338, Republic of Korea.
College of Pharmacy, Chosun University, Gwangju 61452, Republic of Korea.
Toxicol Appl Pharmacol. 2019 Sep 15;379:114665. doi: 10.1016/j.taap.2019.114665. Epub 2019 Jul 16.
Ferroptosis is the non-apoptotic form of cell death caused by small molecules or conditions that inhibit glutathione biosynthesis or resulting in iron-dependent accumulation of lipid peroxidation by lipid reactive oxygen species (ROS). Sestrin2 (Sesn2), a conserved antioxidant protein, is responsive to various stresses including genotoxic, metabolic, and oxidative stresses and acts to restore homeostatic balance. Sesn2 expression was reported to be regulated via stress-responsive transcription factors including p53, Nrf2, and HIF-1α. However, the role of Sesn2 in regulating ferroptosis is not known. In the current study, we investigated whether ferroptosis inducing compounds including erastin, sorafenib, and buthionine sulfoximine affect Sesn2 expression and the role of Sesn2 in cytoprotection against ferroptosis-mediated cell death. Our data demonstrate that ferroptosis inducers significantly increased Sesn2 in hepatocytes in a dose- and time-dependent manner. Treatment with erastin upregulated Sesn2 mRNA levels and luciferase reporter gene activity, and erastin-mediated Sesn2 induction was transcriptionally regulated by NF-E2-related factor 2 (Nrf2). Furthermore, deletion of the antioxidant response element (ARE) in the Sesn2 promoter or Nrf2 knockout or knockdown abolished erastin-induced Sesn2 expression. In cells expressing Sesn2, erastin-induced cell death, ROS formation, and glutathione depletion were almost completely inhibited compared to that in control cells. Treatment with phenylhydrazine in mice, well-reported iron overload liver injury model, increased ALT and AST levels and altered histological features, which were almost completely inhibited by adenoviral Sesn2 infection. Collectively, our results suggest that ferroptosis-mediated Sesn2 induction is dependent on Nrf2 and plays a protective role against iron overload and ferroptosis-induced liver injury.
铁死亡是由小分子或抑制谷胱甘肽生物合成或导致脂质活性氧（ROS）依赖性脂质过氧化积累的条件引起的非凋亡性细胞死亡形式。Sesn2（Sesn2）是一种保守的抗氧化蛋白，对包括遗传毒性、代谢和氧化应激在内的各种应激有反应，并作用于恢复体内平衡。Sesn2 的表达被报道通过应激反应转录因子（包括 p53、Nrf2 和 HIF-1α）进行调节。然而，Sesn2 在调节铁死亡中的作用尚不清楚。在本研究中，我们研究了铁死亡诱导化合物，包括 erastin、sorafenib 和 buthionine sulfoximine 是否影响 Sesn2 的表达以及 Sesn2 在抵抗铁死亡介导的细胞死亡中的细胞保护作用。我们的数据表明，铁死亡诱导剂以剂量和时间依赖的方式显著增加肝细胞中的 Sesn2。Erastin 处理上调 Sesn2 mRNA 水平和荧光素酶报告基因活性，并且 erastin 介导的 Sesn2 诱导受核因子 E2 相关因子 2（Nrf2）转录调节。此外，Sesn2 启动子中的抗氧化反应元件（ARE）缺失或 Nrf2 敲除或敲低消除了 erastin 诱导的 Sesn2 表达。在表达 Sesn2 的细胞中，与对照细胞相比，erastin 诱导的细胞死亡、ROS 形成和谷胱甘肽耗竭几乎完全被抑制。用苯肼处理小鼠，即众所周知的铁过载肝损伤模型，增加 ALT 和 AST 水平并改变组织学特征，这些变化几乎完全被腺病毒 Sesn2 感染抑制。总之，我们的结果表明，铁死亡介导的 Sesn2 诱导依赖于 Nrf2，并在铁过载和铁死亡诱导的肝损伤中发挥保护作用。
