Depletion of cytosolic or mitochondrial thioredoxin increases CYP2E1-induced oxidative stress via an ASK-1-JNK1 pathway in HepG2 cells.
Depletion of cytosolic or mitochondrial thioredoxin increases CYP2E1-induced oxidative stress via an ASK-1-JNK1 pathway in HepG2 cells.
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DOI：
10.1016/j.freeradbiomed.2011.04.030
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发表时间：
2011-07-01
影响因子：
7.4
通讯作者：
Cederbaum, Arthur I.
中科院分区：
文献类型：
--
作者：
Yang, Lili;Wu, Defeng;Wang, Xiaodong;Cederbaum, Arthur I.
硫氧还蛋白是生物系统中重要的还原性分子。增加CYP 2 E1活性可诱导氧化应激和细胞毒性。然而，硫氧还蛋白是否保护细胞免受CYP 2 E1诱导的氧化应激和毒性尚不清楚。siRNA用于敲低表达CYP 2 E1（E47细胞）或不表达CYP 2 E1（C34细胞）的HepG 2细胞中的胞质（TRX-1）或线粒体硫氧还蛋白（TRX-2）。在TRX-1或TRX-2敲低80-90%的情况下，E47细胞的细胞活力降低40-60%，而C34细胞则没有。在E47细胞中，硫氧还蛋白的消耗也增强了谷胱甘肽合成抑制剂或TNFα的毒性。产生活性氧和4-HNE蛋白加合物增加E47，但不是C34细胞与硫氧还蛋白敲低。GSH的减少和添加GSH完全阻断由硫氧还蛋白敲低诱导的E47细胞死亡。在E47细胞中降低TRX-1或TRX-2引起ASK-1的早期激活，随后在siRNA处理48小时后JNK 1磷酸化。JNK抑制剂导致硫氧还蛋白敲低后E47细胞活力的部分恢复。总之，TRX-1或TRX-2的敲低部分通过ASK-1和JNK 1信号通路使细胞对CYP 2 E1诱导的氧化应激敏感。TRX-1和TRX-2对于防御CYP 2 E1诱导的氧化应激都很重要。
Thioredoxin is an important reducing molecule in biological systems. Increasing CYP2E1 activity induces oxidative stress and cell toxicity. However, whether thioredoxin protects cells against CYP2E1 induced oxidative stress and toxicity is unknown. SiRNA were used to knockdown either cytosolic (TRX-1) or mitochondrial thioredoxin (TRX-2) in HepG2 cells expressing CYP2E1 (E47 cells) or without expressing CYP2E1 (C34 cells). Cell viability decreased 40–60% in E47 but not C34 cells with 80–90% knockdown of either TRX-1 or TRX-2. Depletion of either thioredoxin also potentiated the toxicity by either a glutathione synthesis inhibitor or TNFα in E47 cells. Generation of reactive oxygen species and 4-HNE protein adducts increased in E47 but not C34 cells with either thioredoxin knockdown. GSH was decreased and adding GSH completely blocked E47 cell death induced by either thioredoxin knockdown. Lowering TRX-1 or TRX-2 in E47 cells caused an early activation of ASK-1, followed by phosphorylation of JNK1 after 48 hrs of siRNA treatment. JNK inhibitor caused a partial recovery of E47 cell viability after thioredoxin knockdown. In conclusion, knockdown of TRX-1 or TRX-2 sensitizes cells to CYP2E1 induced oxidant stress partially via ASK-1 and JNK1 signaling pathways. Both TRX-1 and TRX-2 are important for defense against CYP2E1-induced oxidative stress.
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