Reactive oxygen species influence nerve growth factor synthesis in primary rat astrocytes.
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 O2.- radical, 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(-4) M 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(-4) M 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 X/XOD-treated 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.(ABSTRACT TRUNCATED AT 250 WORDS)
Naveilhan
P
P
Institut National de la Santé et de la Recherche Médicale, Unité 298, Centre Hospitalier Régional et Universitaire, Angers, France.
Neveu
I
I
Jehan
F
F
Baudet
C
C
Wion
D
D
Brachet
P
P
D000818:Animals; D000841:Anisomycin / Q000494:pharmacology; D001253:Astrocytes / Q000378:metabolism*; D002374:Catalase / Q000494:pharmacology; D002478:Cells, Cultured; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009414:Nerve Growth Factors / Q000096:biosynthesis*; D051381:Rats; D017382:Reactive Oxygen Species / Q000494:pharmacology*; D019820:Xanthine; D014969:Xanthine Oxidase / Q000494:pharmacology; D014970:Xanthines / Q000494:pharmacology
D009414:Nerve Growth Factors; D017382:Reactive Oxygen Species; D014970:Xanthines; D019820:Xanthine; D000841:Anisomycin; D006861:Hydrogen Peroxide; D002374:Catalase; D014969:Xanthine Oxidase