Stabilization of nrf2 by tBHQ confers protection against oxidative stress-induced cell death in human neural stem cells
Stabilization of nrf2 by tBHQ confers protection against oxidative stress-induced cell death in human neural stem cells
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DOI：
10.1093/toxsci/kfi027
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发表时间：
2005-02-01
影响因子：
3.8
通讯作者：
Johnson, J
中科院分区：
文献类型：
--
作者：
Li, J;Johnson, D;Johnson, J
最近的研究表明，NF-E2相关因子2（Nrf 2）是泛素-蛋白酶体途径的底物。本研究的目的是确定增加蛋白质的稳定性是否是醌类化合物，如叔丁基对苯二酚（tBHQ），可以增强Nrf 2介导的转录激活和随后的抗氧化保护的机制。通过透射电子显微镜（TEM）成像证实，无半胱天冬酶3激活和PARP裂解的H2 O2诱导的坏死细胞死亡，通过tBHQ预处理或通过腺病毒介导的人神经干细胞（hNSCs）感染过表达Nrf 2显著减弱。微阵列分析显示，那些鉴定的抗氧化剂基因负责IMR-32细胞中的抗凋亡作用（J. Li等人，2002，J.Biol.Chem.277，388-394），也通过hNSC中Nrf 2依赖性抗氧化剂应答元件（ARE）的活化协同上调。通过脉冲追踪试验证明了在IMR-32细胞中tBHQ对Nrf 2的稳定性，该试验显示tBHQ处理后Nrf 2蛋白合成没有显著增加，并且通过泛素免疫沉淀证明了tBHQ稳定了泛素化的Nrf 2。体外蛋白酶体活性测定表明tBHQ不作为20 S/26 S蛋白酶体抑制剂。在hNSC中也观察到tBHQ对Nrf 2的稳定。总之，这项研究表明，确定的抗氧化剂基因，这是上调通过tBHQ诱导Nrf 2稳定，赋予保护靶细胞对H2 O2诱导的神经母细胞瘤细胞的凋亡细胞死亡，以及在hNSC的坏死细胞死亡。因此，通过药理学调节或腺病毒介导的Nrf 2过表达来稳定Nrf 2可能是预防广谱氧化应激相关神经元细胞损伤的可行策略。
Recent studies indicate that NF-E2 related factor 2 (Nrf2) is a substrate for the ubiquitin-proteasome pathway. The present study is aimed to determine whether increased protein stability is a mechanism by which quinone compounds, like tert-butylhydroquinone (tBHQ), may enhance Nrf2-mediated transcriptional activation and subsequent antioxidant protection. H2O2-induced necrotic cell death, evidenced by transmission electronic microscope (TEM) imaging with no caspase 3 activation and PARP cleavage, was significantly attenuated by pretreatment with tBHQ or overexpression of Nrf2 through advenovirus-mediated infection in human neural stem cells (hNSCs). Microarray analysis showed that those identified antioxidant genes, responsible for antiapoptotic action in IMR-32 cells (J. Li et al., 2002, J. Biol. Chem. 277, 388-394), were also coordinately upregulated through Nrf2-dependent antioxidant responsive element (ARE) activation in hNSC. The stabilization of Nrf2 by tBHQ in IMR-32 cells was evidenced by a pulse-chase assay showing no significant increase in Nrf2 protein synthesis after tBHQ treatment, and by ubiquitin immunoprecipitation showing that tBHQ stabilized ubiquitinated Nrf2. An in vitro proteasomal activity assay showed that tBHQ did not act as a 20S/26S proteasome inhibitor. Nrf2 stabilization by tBHQ also was observed in hNSCs. Taken together, this study suggests that identified antioxidant genes, which were upregulated through tBHQ induced Nrf2 stabilization, confer protection on target cells against H2O2-induced apoptotic cell death in neuroblastoma cells as well as the necrotic cell death in the hNSC. Nrf2 stabilization by pharmacological modulation or adenovirus-mediated Nrf2 overexpression, therefore, might be viable strategies to prevent a wide-spectrum of oxidative stress-related neuronal cell injuries.