Suhara T, Fukuo K, Sugimoto T, Morimoto S, Nakahashi T, Hata S, Shimizu M, Ogihara T
Department of Geriatric Medicine, Osaka University Medical School, Suita, Japan.
J Immunol. 1998 Apr 15;160(8):4042-7.
Hydrogen peroxide (H2O2), an oxidant generated by inflammatory cells, is an important mediator of injury of endothelial cells (ECs). Here we show that H2O2 induces up-regulation of the expression of Fas, a death signal, in human ECs in culture. Flow cytometric analysis with a mAb against human Fas showed that incubation for 24 h with H2O2 induced a dose-dependent increase in the level of Fas in ECs. Coincubation with catalase, which rapidly degrades H2O2, inhibited H2O2-induced up-regulation of Fas. H2O2 also induced a dose-dependent increase in Fas mRNA level. A significant increase in Fas mRNA levels was observed from 6 h after stimulation with H2O2. Vanadate, a protein phosphatase inhibitor, significantly enhanced Fas mRNA and protein levels in H2O2-treated ECs. On the other hand, genistein, a tyrosine kinase inhibitor, inhibited H2O2-induced Fas mRNA expression. Furthermore, a flow cytometric method with propidium iodide staining and electron microscopic analysis showed that incubation with an agonistic Ab against Fas (anti-Fas IgM) induced apoptosis in H2O2-treated cells. These findings suggest that H2O2 induces up-regulation of Fas in ECs and that activation of protein tyrosine kinase may be involved in the mechanism of H2O2-induced Fas expression. Therefore, Fas-mediated apoptosis may have a pathologic role in H2O2-induced EC injury and thereby provide a new therapeutic target.
过氧化氢（H2O2）是炎症细胞产生的一种氧化剂，是内皮细胞（ECs）损伤的重要介质。在此我们表明，H2O2可诱导培养的人内皮细胞中死亡信号Fas表达上调。用抗人Fas单克隆抗体进行的流式细胞术分析显示，与H2O2孵育24小时可诱导内皮细胞中Fas水平呈剂量依赖性增加。与能迅速降解H2O2的过氧化氢酶共同孵育，可抑制H2O2诱导的Fas上调。H2O2还可诱导Fas mRNA水平呈剂量依赖性增加。在用H2O2刺激6小时后，可观察到Fas mRNA水平显著升高。钒酸盐是一种蛋白磷酸酶抑制剂，可显著提高经H2O2处理的内皮细胞中Fas mRNA和蛋白水平。另一方面，酪氨酸激酶抑制剂染料木黄酮可抑制H2O2诱导的Fas mRNA表达。此外，用碘化丙啶染色的流式细胞术方法和电子显微镜分析表明，用抗Fas激动性抗体（抗Fas IgM）孵育可诱导经H2O2处理的细胞发生凋亡。这些发现表明，H2O2可诱导内皮细胞中Fas上调，并且蛋白酪氨酸激酶的激活可能参与H2O2诱导的Fas表达机制。因此，Fas介导的凋亡可能在H2O2诱导的内皮细胞损伤中起病理作用，从而提供一个新的治疗靶点。
