Cholesterol overloading leads to hepatic L02 cell damage through activation of the unfolded protein response
Cholesterol overloading leads to hepatic L02 cell damage through activation of the unfolded protein response
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DOI：
10.3892/ijmm_00000253
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发表时间：
2009-10-01
影响因子：
5.4
通讯作者：
Qu, Shen
中科院分区：
文献类型：
--
作者：
Li, Qi;Liu, Zhiguo;Qu, Shen
已有数据表明，肝脏中的胆固醇负荷可导致肝脏损伤。为探讨胆固醇超负荷致肝细胞损伤的可能机制，以人正常肝细胞系L02为研究对象，检测了细胞凋亡率、未折叠蛋白反应(UPR)及其相互关系。L02细胞与200mgL L L低密度脂蛋白共同孵育2 4h，加或不加2 0mU g/m l脂酰辅酶A：胆固醇酰基转移酶抑制剂58035。在低密度脂蛋白+58035组，细胞内胆固醇水平显著升高，这是用酶结合高效液相色谱法测定的。逆转录-聚合酶链式反应(RT-PCR)或免疫印迹法检测免疫球蛋白结合蛋白、X盒结合蛋白1、激活转录因子6、激活转录因子4、CCAAT/增强子结合蛋白同源蛋白10、内质网应激标志物(ERS/UPR)的表达上调。细胞凋亡率增加21.3+/-2.4%。同时，对照组活跃的caspase-3蛋白表达较活跃的caspase-3蛋白表达增加8.4倍。此外，UPR的抑制剂4-苯丁酸部分减少了细胞的凋亡和caspase-3的激活。这项研究表明，肝脏L02细胞中胆固醇超载诱导ERS并激活UPR，这在一定程度上导致细胞的凋亡损伤。
Reported data indicate that cholesterol loading in the liver can cause hepatic injury. To explore the possible mechanisms of cell damage resulting from cholesterol overloading in hepatocytes, cell apoptosis, the unfolded protein response (UPR) and the correlation between them were assessed in the cholesterol-overloaded normal human hepatic cell line L02. L02 cells were incubated with 200 mu g/ml of low density lipoprotein (LDL) for 24 h with or without 20 mu g/ml 58035, an inhibitor of acyl-CoA:cholesterol acyltransferase (ACAT). In the LDL+58035 group, the intracellular cholesterol level was dramatically increased, which was measured by an enzymatic combined high performance liquid chromatography assay. Expression of immunoglobulin-binding protein, X-box binding protein 1, activating transcription factor 6, activating transcription factor 4, CCAAT/enhancer-binding protein homologous protein-10, markers of endoplasmic reticulum stress (ERS)/UPR, were up-regulated as determined using reverse transcription-polymerase chain reaction (RT-PCR) or Western blot analysis. The rate of cell apoptic death increased 21.3 +/- 2.4%. Meanwhile, the active caspase-3 protein expression was increased 8.4-fold compared to the active caspase-3 protein expression in the controls. Furthermore, 4-phenylbutyric acid, an inhibitor of UPR, partly reduced cell apoptosis and activation of caspase-3. This study suggests that cholesterol overloading in hepatic L02 cells induces ERS and activates the UPR which, in part, leads to the apoptotic damage of cells.