Reactive Oxygen Species Influence Nerve Growth Factor Synthesis in Primary Rat Astrocytes
Reactive Oxygen Species Influence Nerve Growth Factor Synthesis in Primary Rat Astrocytes
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DOI：
10.1046/j.1471-4159.1994.62062178.x
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发表时间：
1994-06
影响因子：
4.7
通讯作者：
P. Naveilhan;I. Neveu;F. Jehan;C. Baudet;D. Wion;P. Brachet
中科院分区：
文献类型：
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作者：
P. Naveilhan;I. Neveu;F. Jehan;C. Baudet;D. Wion;P. Brachet
翻译后摘要：新生大鼠脑星形胶质细胞，在无血清培养基中培养，暴露于两种类型的活性氧30分钟。细胞用黄嘌呤/黄嘌呤氧化酶（X/XOD）系统处理，该系统产生H2 O2和O2β自由基，或仅用H2 O2处理。暴露后6 h，两种处理均诱导神经生长因子（NGF）转录物的剂量依赖性蓄积。用6 mU/ml XOD或10- 4 M H2 O2获得最大效果。在X/XOD或H2 O2处理的细胞中也观察到jun和fos家族的原癌基因的快速表达。这种现象在暴露于X/XOD的细胞中是短暂的。然而，在H2 O2处理的细胞的情况下，在处理结束后6小时，c-fos或c-jun mRNA的积累仍然明显，并且与用X/XOD系统休克后获得的那些相比，细胞分泌的NGF的水平似乎相对降低。这就提出了10 ~（-4）M的H_2O_2抑制蛋白质合成的可能性。放射性标记氨基酸掺入三氯乙酸可沉淀物质的测量结果支持这一假设。与对照或XI XOD处理的细胞相比，H2 O2处理的细胞中与细胞物质相关的放射性水平显著降低。此外，用蛋白质合成抑制剂茴香霉素处理细胞具有与H2 O2相似的效果，因为它在处理6小时后引起c-fos、c-jun和NGF转录物的积累。结论是H2 O2的作用是由于蛋白质合成受损，伴随着c-fos、c-jun或NGF基因的“超诱导”。为了更好地理解X/XOD的效果，在大量过量的过氧化氢酶的存在下进行反应，其去除H2 O2。过氧化氢酶的存在降低了X/XOD处理的NGF基因的响应幅度。相反，低剂量的H2 O2和X/ XOD比单独的每种处理更有效地产生NGF。这些结果表明，O2β和H2 O2都是NGF基因激活过程中的重要代谢产物，可能通过形成OH* 自由基或其他反应产物，从而构成活性调节分子。
Abstract: Newborn rat brain astrocytes, cultured in a serum‐free medium, were exposed for 30 min to two types of reactive oxygen species. Cells were either treated with the xanthine/xanthine oxidase (X/XOD) system, which generates both H2O2 and the O2βradical, or to H2O2 alone. Both treatments induced a dose‐dependent accumulation of nerve growth factor (NGF) transcripts, 6 h after the exposure. Maximal effect was obtained with 6 mU/ml XOD, or 10–4M H2O2. A rapid expression of protooncogenes of the jun and fos families was also noticed in X/XOD‐or H2O2‐treated cells. This phenomenon was transient in cells exposed to X/XOD. However, in the case of H2O2‐treated cells, the accumulation of c‐fos or c‐jun mRNAs was still pronounced 6 h after the end of the treatment and the levels of cell‐secreted NGF appeared relatively reduced, when compared with those obtained after a shock with the X/XOD system. This raised the possibility that H2O2 at 10–4M could depress protein synthesis. Measurements of the incorporation of radiolabeled amino acids into trichloroacetic acid‐precipitable material supported this assumption. Level of radioactivity associated with cellular material was dramatically reduced in H2O2‐treated cells, when it was compared with control or XI XOD‐trreated cells. Furthermore, treatment of cells with the protein synthesis inhibitor anisomycin had an effect similar to that of H2O2 because it caused an accumulation of c‐fos, c‐jun, and NGF transcripts after 6 h of treatment. It is concluded that the effect of H2O2 results from an impairment of protein synthesis, which is accompanied by the “superinduction” of c‐fos, c‐jun, or NGF genes. To understand better the effect of X/XOD, the reaction was conducted in the presence of a large excess of catalase, which removes H2O2. The presence of catalase reduced the amplitude of the response of the NGF gene to the X/XOD treatment. Conversely, low doses of H2O2 and X/ XOD were more efficient for the production of NGF than each treatment alone. These results suggest that both O2β and H2O2 are important metabolites in the process of activation of the NGF gene, possibly via the formation of the OH* radical or other reactive products, which could constitute active regulatory molecules.