Epimorphin protects hepatocytes from oxidative stress by inhibiting mitochondrial injury
Epimorphin protects hepatocytes from oxidative stress by inhibiting mitochondrial injury
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DOI：
10.1111/j.1440-1746.2010.06327.x
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发表时间：
2011-01-01
影响因子：
4.1
通讯作者：
Ohnishi, Hirohide
中科院分区：
文献类型：
--
作者：
Kinoshita, Nobukatsu;Horie, Yasuo;Ohnishi, Hirohide
背景和目的：许多研究表明，活性氧（ROS）产生引起的细胞损伤是各种肝脏疾病的常见机制。最近，我们证明了 Epimorphin（最初克隆为间充质蛋白）可以保护培养的肠上皮细胞免受 ROS 的影响。因此，我们研究了 Epimorphin 是否可以保护原代培养的肝细胞免受 ROS 诱导的细胞损伤。方法：我们探讨了纯化的小鼠肝细胞暴露于 0.5 mM H2O2（有或没有 Epimorphin 预处理）后的细胞活力和细胞内 ROS 水平。然后，我们利用共聚焦显微镜观察线粒体通透性转变（MPT）和去极化，以明确Epimorphin抑制H2O2暴露后细胞损伤的机制。此外，为了阐明与细胞存活相关的信号通路，我们使用磷酸化应激激活蛋白激酶/c-Jun N末端激酶（SAPK/JNK）多克隆抗体进行Western blotting分析，以评估epimorphin对JNK的抑制作用。最后，我们评估了施用 JNK 抑制剂的肝细胞中的细胞活力。结果：Epimorphin 保护原代培养的肝细胞免受 H2O2 诱导的细胞损伤，与细胞内 ROS 水平无关。 Epimorphin 还抑制 MPT 的发生、线粒体膜电位的去极化以及最终的细胞杀伤。 Epimorphin接触H2O2后的细胞保护功能不依赖于Akt信号，而是依赖于JNK信号。结论：Epimorphin可以保护肝细胞免受ROS诱导的MPT依赖性细胞损伤。由于肝脏疾病可能是由 MPT 依赖性细胞损伤和过量 ROS 引起的，因此 Epimorphin 可能为肝脏疾病开辟一条新的治疗途径。
Background and Aims:Many investigations have demonstrated that cell injuries caused by generation of reactive oxygen species (ROS) is a common mechanism of various hepatic disorders. Recently, we have demonstrated that epimorphin, originally cloned as a mesenchymal protein, protects cultured intestinal epithelial cells from ROS. We therefore examine whether epimorphin protects primary cultured hepatocytes from ROS-induced cell injury.Methods:We explored the cell viability and the intracellular ROS levels of purified murine hepatocytes after exposure to 0.5 mM H2O2 with or without pretreatment of epimorphin. Then, we observed mitochondrial permeability transition (MPT) and depolarization using confocal microscopy to make clear the mechanism that epimorphin inhibited cell injuries after exposure to H2O2. In addition, to clarify the signaling pathways related to cell survival, we carried out Western blotting analysis with phosphorylated stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) polyclonal antibody to evaluate the inhibition of JNK by epimorphin. Finally, we evaluated the cell viability in hepatocytes administered JNK inhibitor.Results:Epimorphin protected primary cultured hepatocytes from H2O2-induced cell injuries independent of intracellular ROS levels. Epimorphin also inhibited onset of MPT, depolarization of the mitochondrial membrane potential, and eventually cell killing. The cell protective function of epimorphin after exposure to H2O2 was not dependent on Akt signaling but on JNK signaling.Conclusion:Epimorphin can protect hepatocytes from MPT-dependent cell injury induced by ROS. Since hepatic disorders could be caused by MPT-dependent cell injuries with excessive ROS, epimorphin might open a new therapeutic avenue for hepatic disorders.