Activation, involvement and nuclear translocation of c-Jun N-terminal protein kinase 1 and 2 in glutamate-induced apoptosis in cultured rat cortical neurons.
Previous studies showed that c-Jun N-terminal protein kinase 1 and 2 (JNK1&2) were activated in some cases of excitotoxicity. In the present study, activation, subcellular distribution, involvement and upstream regulation of JNK1&2 were investigated in glutamate-induced excitotoxicity in cultured rat cortical neurons. As indicated by Western immunoblot from whole cellular extracts, while JNK1&2 were not significantly changed, the activated JNK1&2 (diphosphorylated JNK1&2, p-JNK1&2), were rapidly increased at 15 min exposure to 50 microM glutamate and reverted to basal level at 12 h after exposure, followed by a significant increase of apoptotic-like cell death as detected by DAPI (a fluorescent DNA binding dye) staining at 9-18 h after exposure. Blockage of the increase of p-JNK1&2 with JNK1&2 antisense oligodeoxynucleotides significantly prevented the cell death. The increase of p-JNK1&2 was largely prevented by blockage of NMDA receptor (a subtype of glutamate receptor) or protein kinase C (PKC), and each blockage also largely prevented the cell death. Combined blockage of PKC and JNK1&2 had no additive protective effect against cell death. Immunocytochemistry study showed at 15 min of glutamate exposure a whole cellular but mainly nuclear increase of p-JNK1&2, together with mild plasma decrease but large nuclear increase of JNK1&2, all of which were also largely prevented by blockage of NMDA receptor or PKC. These results suggested that mainly downstream of NMDA receptor-PKC pathway JNK1&2 were activated, nuclear translocated and causally involved in the glutamate-induced excitotoxicity, possibly through a nuclear elevation of p-JNK1&2.
Jiang
Qian
Q
Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, 84 West Huai-hai Road, Xuzhou, Jiangsu 221002, People's Republic of China.
Gu
Zhenglin
Z
Zhang
Guangyi
G
D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D018929:Cell Culture Techniques; D002467:Cell Nucleus / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D018698:Glutamic Acid; D007150:Immunohistochemistry; D048055:Mitogen-Activated Protein Kinase 8; D048056:Mitogen-Activated Protein Kinase 9; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D019579:Neocortex / Q000166:cytology / Q000378:metabolism*; D009474:Neurons / Q000648:ultrastructure*; D009498:Neurotoxins; D019001:Nitric Oxide Synthase / Q000378:metabolism; D010766:Phosphorylation; D011493:Protein Kinase C / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D014178:Translocation, Genetic
D009498:Neurotoxins; D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D019001:Nitric Oxide Synthase; D048056:Mitogen-Activated Protein Kinase 9; D011493:Protein Kinase C; D048055:Mitogen-Activated Protein Kinase 8; D020928:Mitogen-Activated Protein Kinases