Activation of the ER stress gene gadd153 by hepatitis C virus sensitizes cells to oxidant injury
Activation of the ER stress gene gadd153 by hepatitis C virus sensitizes cells to oxidant injury
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DOI：
10.1016/j.virusres.2007.02.006
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发表时间：
2007-06-01
期刊：
影响因子：
5
通讯作者：
Rapicetta, M.
中科院分区：
文献类型：
--
作者：
Ciccaglione, A. R.;Marcantonio, C.;Rapicetta, M.
HCV诱导内质网（ER）应激，其与ER应激基因的转录诱导相关。以前，我们报道了HCV结构蛋白的表达激活ER应激和促凋亡基因gadd153，其在氧化应激诱导的细胞死亡中起相关作用。在本研究中，使用携带全长HCV复制子的人肝细胞系Huh7，我们证明了完整的HCV蛋白的复制和表达与gadd153的表达升高相关。对gadd153启动子活性的分析表明，通常在ER应激反应期间诱导的ATF4和ATF6途径都有助于HCV复制子细胞中gadd153的诱导。通过鉴定复制子细胞中增加的ATF 4蛋白水平证实了ATF 4途径的激活。重要的是，我们发现，H2O2处理后，gadd153基因在复制子细胞中达到更高的表达水平。与促凋亡基因gadd153的显著诱导一致，HCV复制子细胞表现出对氧化损伤的脆弱性增加。用针对gadd153基因的特异性小干扰RNA处理复制子细胞，降低了gadd153的基础表达，并降低了H2O2后的细胞死亡。这些结果表明gadd153可能在HCV复制子细胞对氧化应激的敏感性中起主要作用。(C)2007 Elsevier B.V.保留所有权利。
HCV induces endoplasmic reticulum (ER) stress which correlates with transcriptional induction of ER stress genes. Previously, we reported that expression of HCV structural proteins activates the ER stress and pro-apoptotic gene gadd153 which plays a relevant role in cell death induced by oxidative stress. In the present study, using human hepatic cell lines Huh7 carrying a full-length HCV replicon, we demonstrated that replication and expression of the complete set of HCV proteins were associated with elevated expression of gadd153. Analysis of gadd153 promoter activity revealed that both the ATF4 and the ATF6 pathways, which are typically induced during ER stress response, contribute to the induction of gadd153 in HCV replicon cells. Activation of the ATF4 pathway was confirmed by identification of increased levels of ATF4 protein in replicon cells. Importantly, we showed that, following H2O2 treatment, gadd153 gene reached higher levels of expression in replicon cells. Consistent with the marked induction of the pro-apoptotic gene gadd153, HCV replicon cells showed an increased vulnerability to oxidant injury. Treatment of replicon cells with a specific small interfering RNA, targeted to gadd153 gene, reduced basal expression of gadd153 and decreased cell death following H2O2. These findings suggest that gadd153 may play a major role in sensitivity of HCV replicon cell to oxidative stress. (C) 2007 Elsevier B.V. All rights reserved.