REGULATION AND BIOLOGICAL ROLE OF ETHANOL INDUCIBLE CYTOCHROME P450 2E1 (CYP2E1)

我们已经证明了多重监管 细胞色素P450-2E1的机制：通过转录、mRNA诱导 稳定、激活信使核糖核酸翻译和蛋白 稳定，转录抑制，mRNA降解和 蛋白质降解。我们最近报道了转录 外源化合物YH439对细胞色素P421基因的抑制作用 在体内研究了YH439的潜在有益作用。 四氯化碳治疗急性肝炎模型的建立。在……里面 活体肝胆成像分析显示YH439有效 保护四氯化碳对肝脏的损伤。这些结果是 通过相应的血清水平变化来证实 转氨酶和组织学评估。这些数据是 最近发表在Nucl上。地中海医院。比奥尔。因为最近有很多人 关于酶在早期信号中的作用的报道 在细胞死亡中的转导，这些酶在碳中的活性 对四氯化碳处理的大鼠肝脏进行测量。C-jun的水平 一过性的(1-2小时)和选择性地激活了激酶活性 而p-38蛋白激酶或有丝分裂原激活的蛋白激酶 保持不变。与活体数据一致，我们还 观察到PC12和COS-7细胞中的c-jun激酶是选择性的 由4-羟基壬烯醛(HNE)激活，另一种细胞毒性 CYP2E1介导的长链代谢产物 脂肪酸。C-jun的选择性激活依赖于hNe HNE上的浓度和瞬时(15-30分钟内) 治疗，早在凋亡性细胞死亡之前。为了进一步澄清 C-jun激酶激活与细胞死亡的关系 一种体外模型，我们最近转染了人的细胞色素P4502 通过稳定的转染法将其导入人肝癌细胞株HepG2和神经细胞株Neuro2中。vbl.使用 这些细胞具有高水平的CYP2E1蛋白和作为IN的活性 细胞死亡的体外模型，我们正在测试各种 CYP2E1底物包括乙醇、花生四烯酸和 对乙酰氨基酚(泰诺)。此外，水平的变化， 细胞内DNA加合物在细胞中的作用 正在用高效液相色谱法测定CYP2E1底物。

We have demonstrated multiple regulatory mechanisms for CYP2E1: induction via transcription, mRNA stabilization, activation of mRNA translation and protein stabilization, suppression via transcription, mRNA degradations and protein degradation. We have recently reported transcriptional suppression of CYP2E1 gene by an exogenous compound, YH439. The potential beneficial effect of YH439 were studied in an in vivo model of acute hepatitis by treatment with carbon tetrachloride. In vivo hepatobiliary imaging analyses revealed that YH439 efficiently protects liver injury from carbon tetrachloride. These results were confirmed by the corresponding changes in the levels of serum transaminases and by histological evaluations. These data were recently published in Nucl. Med. Biol. Because of numerous recent reports about the role of enzymes involved in early signal transduction in cell death, activities of these enzymes in carbon tetrachloride-treated rat livers were measured. The level of c-jun kinase activity was transiently (1-2 hr) and selectively activated while p-38 protein kinase or mitogen activated protein kinase remained unchanged. Consistent with the in vivo data, we also observed that c-jun kinase in PC12 and COS-7 cells was selectively activated by 4-hydroxynonenal (HNE), another cytotoxic metabolite from the CYP2E1-mediated metabolism of long chain fatty acids. The selective c-jun activation was dependent upon HNE concentration and transient (within 15-30 min) upon HNE treatment, long before the apoptotic cell death. To further elucidate the relationship between the c-jun kinase activation and cell death in an in vitro model, we have recently transfected human CYP2E1 cDNA into HepG2 and Neuro2 cells via stable transfection. Using these cells with high level of CYP2E1 protein and activity as an in vitro model of cell death, we are testing the effects of various CYP2E1 substrates including ethanol, arachidonic acid and acetaminophen (Tylenol). In addition, changes in the level of DNA-adducts in the CYP2E1-transfected cells, upon treatment of CYP2E1 substrates, are being determined by HPLC.