Han Jae Yun, Cho Seung Sik, Yang Ji Hye, Kim Kyu Min, Jang Chang Ho, Park Da Eon, Bang Joon Seok, Jung Young Suk, Ki Sung Hwan
College of Pharmacy, Chosun University, Gwangju 501-759, Republic of Korea.
College of Pharmacy, Mokpo National University, Muan, Jeonnam 535-729, Republic of Korea.
Toxicol Appl Pharmacol. 2015 Aug 15;287(1):77-85. doi: 10.1016/j.taap.2015.05.015. Epub 2015 May 29.
The chalcone compound isosalipurposide (ISPP) has been successfully isolated from the native Korean plant species Corylopsis coreana Uyeki (Korean winter hazel). However, the therapeutic efficacy of ISPP remains poorly understood. This study investigated whether ISPP has the capacity to activate NF-E2-related factor (Nrf2)-antioxidant response element (ARE) signaling and induce its target gene expression, and to determined the protective role of ISPP against oxidative injury of hepatocytes. In HepG2 cells, nuclear translocation of Nrf2 is augmented by ISPP treatment. Consistently, ISPP increased ARE reporter gene activity and the protein levels of glutamate cysteine ligase (GCL) and hemeoxygenase (HO-1), resulting in increased intracellular glutathione levels. Cells pretreated with ISPP were rescued from tert-butylhydroperoxide-induced reactive oxygen species (ROS) production and glutathione depletion and consequently, apoptotic cell death. Moreover, ISPP ameliorated the mitochondrial dysfunction and apoptosis induced by rotenone which is an inhibitor of complex 1 of the mitochondrial respiratory chain. The specific role of Nrf2 activation by ISPP was demonstrated using an ARE-deletion mutant plasmid and Nrf2-knockout cells. Finally, we observed that extracellular signal-regulated kinase (ERK) and AMP-activated protein kinase (AMPK), but not protein kinase C (PKC)-δ or other mitogen-activated protein kinases (MAPKs), are involved in the activation of Nrf2 by ISPP. Taken together, our results demonstrate that ISPP has a cytoprotective effect against oxidative damage mediated through Nrf2 activation and induction of its target gene expression in hepatocytes.
查尔酮化合物异水杨苷（ISPP）已成功从韩国本土植物物种朝鲜蜡瓣花（Korean winter hazel）中分离出来。然而，ISPP的治疗效果仍知之甚少。本研究调查了ISPP是否具有激活核因子E2相关因子（Nrf2）-抗氧化反应元件（ARE）信号通路并诱导其靶基因表达的能力，并确定了ISPP对肝细胞氧化损伤的保护作用。在HepG2细胞中，ISPP处理可增强Nrf2的核转位。一致地，ISPP增加了ARE报告基因活性以及谷氨酸半胱氨酸连接酶（GCL）和血红素加氧酶（HO-1）的蛋白水平，从而导致细胞内谷胱甘肽水平升高。用ISPP预处理的细胞可免受叔丁基过氧化氢诱导的活性氧（ROS）产生和谷胱甘肽耗竭，进而免受凋亡性细胞死亡。此外，ISPP改善了由线粒体呼吸链复合物1的抑制剂鱼藤酮诱导的线粒体功能障碍和凋亡。使用ARE缺失突变体质粒和Nrf2基因敲除细胞证明了ISPP激活Nrf2的特定作用。最后，我们观察到细胞外信号调节激酶（ERK）和AMP激活的蛋白激酶（AMPK），而非蛋白激酶C（PKC）-δ或其他丝裂原活化蛋白激酶（MAPK），参与了ISPP对Nrf2的激活。综上所述，我们的结果表明，ISPP对通过激活Nrf2及其在肝细胞中靶基因表达介导的氧化损伤具有细胞保护作用。
