Phagocytosis and H2O2 induce catalase and metallothionein gene expression in human retinal pigment epithelial cells.
Phagocytosis and H2O2 induce catalase and metallothionein gene expression in human retinal pigment epithelial cells.
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发表时间：
1995-06
影响因子：
4.4
通讯作者：
David J. Tale;M. Miceli;David;-A.;Newsome
中科院分区：
文献类型：
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作者：
David J. Tale;M. Miceli;David;-A.;Newsome
活性氧中间体与衰老过程和眼睛退行性疾病有关，包括早产儿视网膜病变、白内障发生和黄斑变性。本研究旨在探讨光感受器外段吞噬和外源H2O2的加入对人视网膜色素上皮细胞过氧化氢酶和金属硫蛋白表达的影响。方法用牛光感受器外段或H2O2处理融合型RPE细胞6或18小时。6 h后采用槽点杂交法检测过氧化氢酶和金属硫蛋白基因的表达。18 h后测定过氧化氢酶活性和金属硫蛋白含量。结果吞噬作用或添加H2O2使过氧化氢酶活性和金属硫蛋白比对照水平提高2倍。n-乙酰半胱氨酸的加入消除了两种胁迫引起的诱导效应。槽印迹杂交法检测过氧化氢酶和金属硫蛋白基因表达，结果表明两种胁迫均可显著诱导过氧化氢酶和金属硫蛋白基因表达。光感受器外段的吞噬作用使细胞外H2O2浓度增加9倍以上。结论视网膜色素上皮细胞对吞噬的反应与添加外源H2O2后观察到的反应没有区别。吞噬过程中H2O2的产生可能作为视网膜色素上皮细胞的细胞内信号，导致关键抗氧化酶和其他保护细胞免受氧化损伤的重要蛋白质水平升高。
PURPOSE Reactive oxygen intermediates have been implicated in the aging process and degenerative diseases of the eye, including retinopathy of prematurity, cataractogenesis, and macular degeneration. The purpose of this study was to investigate the effect of phagocytosis of photoreceptor outer segments and the addition of exogenous H2O2 on catalase and metallothionein expression in human retinal pigment epithelial cells. METHODS Confluent RPE cells were treated with bovine photoreceptor outer segments or H2O2 for either 6 or 18 hours. Slot blot hybridization was used to assess catalase and metallothionein gene expression after 6 hours. Catalase enzyme activity and metallothionein content were measured after 18 hours. RESULTS Phagocytosis or the addition of H2O2 increased catalase enzyme activity and metallothionein twofold above control levels. The addition of n-acetyl cysteine abrogated the inductive effect caused by either stress. Catalase and metallothionein gene expression, measured by slot blot hybridization, also were measurably induced by either stress. Phagocytosis of photoreceptor outer segments increased extracellular H2O2 concentration nine times above control. CONCLUSIONS The response of the retinal pigment epithelial cells to phagocytosis was indistinguishable from the response observed after the addition of exogenous H2O2. The generation of H2O2 during phagocytosis may act as an intracellular signal in retinal pigment epithelial cells that leads to increased levels of key antioxidant enzymes and other proteins important for protecting the cells from oxidative damage.