title: Hydrogen peroxide-mediated phosphorylation of ERK1/2, Akt/PKB and JNK in cortical neurones: dependence on Ca(2+) and PI3-kinase.
abstract: Primary cortical neurones exposed to an oxidative insult in the form of hydrogen peroxide (H(2)O(2)) for 30 min showed a concentration-dependent increase in oxidative stress followed by a delayed NMDA receptor-dependent cell death measured 24 h later. Extracellular signal-regulated protein kinase (ERK1/2), c-jun N-terminal kinase (JNK) and the kinase Akt/PKB may regulate neuronal viability in response to oxidative insults. Using phospho-specific antibodies, a 15-min stimulation of neurones with H(2)O(2) (100 microm - 1 mm) produced a concentration-dependent phosphorylation of ERK1/2 and Akt/PKB that was partly dependent on extracellular Ca(2+) and phosphatidylinositol 3-kinase (PI3-K). Higher concentrations of H(2)O(2) (1 mm) also stimulated a phosphorylation of JNK which was totally dependent on extracellular Ca(2+) but not PI3-K. H(2)O(2)-induced phosphorylation of ERK1/2, Akt/PKB or JNK were unaffected by the NMDA channel blocker MK801. Blocking ERK1/2 activation with the upstream inhibitor U0126 (10 microm) enhanced H(2)O(2)-induced (100-300 microm range) neurotoxicity and inhibited H(2)O(2)-mediated phosphorylation of the cyclic AMP regulatory binding protein (CREB), suggesting that ERK1/2 signals to survival under these conditions. At higher concentrations (mm), H(2)O(2)-stimulated a phosphorylation of c-jun. It is likely, therefore, that subjecting neurones to moderate oxidative-stress recruits pro-survival signals to CREB but during severe oxidative stress pro-death signals through JNK and c-jun are dominant.
authors.affiliation: Centre for Neuroscience Research, Guy's, King's and St. Thomas' School of Biomedical Sciences, Guy's Campus, London, UK.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Crossthwaite
authors.forename: Sumaera
authors.initials: S
authors.lastname: Hasan
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Williams
mesh_terms: D000818:Animals; D002118:Calcium / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism*; D004622:Embryo, Mammalian; D004789:Enzyme Activation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D048031:JNK Mitogen-Activated Protein Kinases; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism / Q000502:physiology; D016877:Oxidants / Q000494:pharmacology*; D018384:Oxidative Stress; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000502:physiology
chemical_list: D002118:Calcium; D006861:Hydrogen Peroxide; D048031:JNK Mitogen-Activated Protein Kinases; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D048055:Mitogen-Activated Protein Kinase 8; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases; D016877:Oxidants; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D016755:Proto-Oncogene Proteins c-jun; D016194:Receptors, N-Methyl-D-Aspartate