Hypoxia/reoxygenation up-regulated the expression of death receptor 5 and enhanced apoptosis in human hepatocyte line
Hypoxia/reoxygenation up-regulated the expression of death receptor 5 and enhanced apoptosis in human hepatocyte line
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DOI：
10.1016/j.transproceed.2006.06.014
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发表时间：
2006-09-01
影响因子：
0.9
通讯作者：
Long, D.
中科院分区：
文献类型：
--
作者：
Cao, L.;Li, Y.;Long, D.
目标。缺血再灌注损伤（IRI）是导致肝移植早期和晚期功能障碍的关键因素。尽管我们知道肝细胞表达肿瘤坏死因子相关凋亡诱导配体（TRAIL）的死亡受体，但 TRAIL 对缺氧/复氧（H/R）介导的细胞凋亡的影响尚不清楚。本研究旨在探讨 H/R 对 TRAIL 细胞毒性的影响，作为原发性肝移植功能障碍、延迟性移植物再功能和慢性移植物功能障碍的原因。方法。使用体外肝细胞 H/R 模型模拟移植肝脏中的 IRI，将正常人肝细胞 HL-7702 暴露于缺氧 5 小时，然后再充氧 0、2、4、6 或 20 小时。在另一项实验中，肝细胞处于缺氧状态 0、2、4、8 或 20 小时。通过半定量逆转录酶聚合酶链反应测量 TRAIL-R2/死亡受体 5 (DR5) mRNA 的表达。缺氧16小时后，用不同浓度的TRAIL处理人肝细胞5小时。通过流式细胞仪和甲基噻唑基四唑分析证实肝细胞死亡。结果。缺氧5小时后，DR5 mRNA的表达在复氧的所有时间均增加。与常氧培养细胞相比，DR5 mRNA从复氧后0小时开始上调，复氧后2小时达到峰值。此外，长时间缺氧后DR5 mRNA逐渐上调。与常氧组相比，低氧治疗组的 TRAIL 介导的细胞杀伤具有浓度依赖性。结论。 H/R 上调 DR5 的表达并增强人肝细胞系中 TRAIL 介导的细胞凋亡。 TRAIL通路可能在IRI诱导的肝细胞凋亡中发挥关键作用。
Objectives. Ischemia-reperfusion injury (IRI) is a key factor that contributes to early and late dysfunction of liver graft. Although we have known that hepatocytes express death receptors for tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), the effects of TRAIL on hypoxia/reoxygenation (H/R)-mediated apoptosis are unclear. This study sought to examine the effects of H/R on TRAIL cytotoxicity, as a cause of primary hepatic graft dysfunction, delayed graft refunction, and chronic graft dysfunction.Methods. Using an hepatocyte H/R model in vitro to mimic IRI in the grafted liver, normal human hepatocytes HL-7702 were exposed to hypoxia for 5 hours then reoxygenated for 0, 2, 4, 6, or 20 hours. In another experiment, hepatocytes were exposed to hypoxia for 0, 2, 4, 8, or 20 hours. Expressions of TRAIL-R2/Death receptor 5 (DR5) mRNA were measured by semiquantitative reverse-transcriptase polymerase chain reactions. After 16 hours of hypoxia, human hepatocytes were treated with TRAIL in different concentrations for 5 hours. The death of hepatocytes was confirmed by flow cytometer and methyl thiazolyl tetrazolium analysis.Result. After 5-hour hypoxia, the expressions of DR5 mRNA increased at all times of reoxygeriation. DR5 mRNA was up-regulated from 0 hour after reoxygenation, reaching a peak value at 2 hours after reoxygenation compared with the normoxia cultured cells. Moreover, DR5 mRNA was up-regulated gradually following prolonged hypoxia. TRAIL-mediated cell killing was concentration-dependent being greater in the hypoxia treatment group compared to the normoxia group.Conclusions. H/R up-regulated the expression of DR5 and enhanced TRAIL-mediated apoptosis in an human hepatocyte line. The TRAIL pathway might play a critical role hepatocyte apoptosis induced by IRI.