Hydrogen peroxide and redox modulation sensitize primary mouse hepatocytes to TNF-induced apoptosis
Hydrogen peroxide and redox modulation sensitize primary mouse hepatocytes to TNF-induced apoptosis
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DOI：
10.1016/j.freeradbiomed.2006.05.002
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发表时间：
2006-08-15
影响因子：
7.4
通讯作者：
Kaplowitz, Neil
中科院分区：
文献类型：
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作者：
Han, Derick;Hanawa, Naoko;Kaplowitz, Neil
肿瘤坏死因子α（TNF）在介导各种肝脏病理中的肝细胞损伤中起重要作用。TNF单独处理不会导致原代培养肝细胞死亡，表明其他因素是必要的，介导TNF诱导的损伤。在这项工作中，活性氧是否可以敏感的原代培养的肝细胞肿瘤坏死因子诱导的凋亡和坏死的问题进行了研究。亚致死水平的H2 O2，无论是作为团注剂量或葡萄糖氧化酶产生的稳态水平，被发现培养的肝细胞对TNF诱导的细胞凋亡敏感。无论是否存在TNF，高水平的H2 O2也引发肝细胞坏死。同样，抗霉素，一种复合物III抑制剂，增加活性氧从线粒体产生，致敏肝细胞TNF诱导的细胞凋亡在低剂量，但在高剂量引起坏死。氧化还原的变化似乎是重要的致敏原代肝细胞，因为二酰胺，硫醇氧化剂，和1，3-双（2-氯乙基）-1-亚硝基脲（BCNU），GSSG还原酶的抑制剂，也增加了TNF诱导的原代肝细胞凋亡在亚致死剂量。高剂量的联酰胺和BCNU主要引发坏死细胞死亡。使肝细胞对TNF诱导的凋亡敏感的试剂-H2 O2、抗霉素、联胺、BCNU-都引起GSH/GSSG比率的急剧下降。发现这些氧化还原改变抑制TNF诱导的I κ B-α磷酸化和NF-κ B易位至细胞核，从而推测抑制抑制TNF细胞毒性作用所必需的基因的表达。综上所述，这些结果表明，活性氧或氧化还原调节剂对肝细胞内环境的氧化干扰了NF-κ B信号通路，使肝细胞对TNF诱导的细胞凋亡敏感。TNF诱导的细胞凋亡似乎只发生在一定的氧化还原范围内，在此范围内，氧化还原变化可抑制NF-κ B B活性，但不能完全抑制caspase活性。肝病的含义是伴随的TNF暴露和活性氧，无论是外源性产生的（例如，非实质或炎症细胞）或在肝细胞中固有产生（例如，线粒体），可能共同作用以促进细胞凋亡和肝损伤。(c)2006年爱思唯尔公司All rights reserved.
Tumor necrosis factor alpha (TNF) plays an important role in mediating hepatocyte injury in various liver pathologies. TNF treatment alone does not cause the death of primary cultured hepatocytes, suggesting other factors are necessary to mediate TNF-induced injury. In this work the question of whether reactive oxygen species can sensitize primary cultured hepatocytes to TNF-induced apoptosis and necrosis was investigated. Sublethal levels of H2O2, either as bolus doses or steady-state levels generated by glucose oxidase, were found to sensitize cultured hepatocytes to TNF-induced apoptosis. High levels of H2O2 also triggered necrosis in hepatocytes regardless of whether TNF was present. Similarly, antimycin, a complex III inhibitor that increases reactive oxygen species generation from mitochondria, sensitized hepalocytes to TNF-induced apoptosis at low doses but caused necrosis at high doses. Redox changes seem to be important in sensitizing primary hepatocytes, because diamide, a thiol-oxidizing agent, and 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), an inhibitor of GSSG reductase, also increased TNF-induced apoptosis in cultured primary hepatocytes at sublethal doses. High doses of diamide and BCNU predominantly triggered necrotic cell death. Agents that sensitized hepatocytes to TNF-induced apoptosis-H2O2, antimycin, diamide, BCNU-all caused a dramatic fall in the GSH/GSSG ratio. These redox alterations were found to inhibit TNF-induced I kappa B-alpha phosphorylation and NF-kappa B translocation to the nucleus, thus presumably inhibiting expression of genes necessary to inhibit the cytotoxic effects of TNF. Taken together, these results suggest that oxidation of the intracellular environment of hepatocytes by reactive oxygen species or redox-modulating agents interferes with NF-kappa B signaling pathways to sensitize hepatocytes to TNF-induced apoptosis. The TNF-induced apoptosis seems to occur only in a certain redox range-in which redox changes can inhibit NF-kappa B activity but not completely inhibit caspase activity. The implication for liver disease is that concomitant TNF exposure and reactive oxygen species, either extrinsically generated (e.g., nonparenchymal or inflammatory cells) or intrinsically generated in hepatocytes (e.g., mitochondria), may act in concert to promote apoptosis and liver injury. (c) 2006 Elsevier Inc. All rights reserved.