Antioxidant N-acetylcysteine inhibits the activation of JNK3 mediated by the GluR6-PSD95-MLK3 signaling module during cerebral ischemia in rat hippocampus.
Cerebral ischemia induces kainate receptor glutamate receptor 6 (GluR6) binding to the postsynaptic density protein 95 (PSD95), which in turn anchors mixed lineage kinase 3 (MLK3) via SH3 domain in rat brain. MLK3 subsequently activates c-Jun NH(2)-terminal kinase (JNK) via MAP kinase kinases (MKKs). In this study, we investigated the association of PSD95 with GluR6 and MLK3, the autophosphorylation of MLK3, the combination of MLK3 with JNK3, and the phosphorylation of JNK3 during cerebral ischemia in rat hippocampus CA1. Our results indicate that the GluR6-PSD95-MLK3 complex quickly enhanced at 5 min of ischemia and peaked at 10 min of ischemia, and then gradually reduced with the prolonged time of ischemia. Interestingly, the combination of MLK3 and JNK3 gradually increased from 5 min to 30 min of ischemia. JNK3 phosphorylation first increased and then attenuated in cytosol, suggesting the translocation of activated JNK3 to nucleus during ischemia. To further investigate the possible mechanism of JNK3 activation, antioxidant N-acetylcysteine (NAC) was given to the rats 20 min prior to ischemia. Results indicate that NAC distinctly inhibited the association of PSD95 with GluR6 and MLK3, the autophosphorylation of MLK3, the combination of MLK3 with JNK3 and JNK3 activation. Taken together, these finding indicate that ischemic stimulation results in JNK3 activation through the GluR6-PSD95-MLK3 signaling module, and that the activation of JNK3 is closely related to oxidative stress.
Zhang
Quan-Guang
QG
Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, Xuzhou, Jiangsu 221002, PR China.
Tian
Hui
H
Li
Hong-Chun
HC
Zhang
Guang-Yi
GY
D000111:Acetylcysteine / Q000494:pharmacology* / Q000627:therapeutic use; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology* / Q000627:therapeutic use; D015153:Blotting, Western; D002545:Brain Ischemia / Q000188:drug therapy / Q000473:pathology*; D004195:Disease Models, Animal; D000076122:Disks Large Homolog 4 Protein; D004789:Enzyme Activation / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006624:Hippocampus / Q000187:drug effects*; D006801:Humans; D047468:Immunoprecipitation / Q000379:methods; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D020930:MAP Kinase Kinase Kinases / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D048057:Mitogen-Activated Protein Kinase 10 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018092:Kainic Acid Receptors / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013997:Time Factors; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; D000097806:GluK2 Kainate Receptor
D000111:Acetylcysteine; D000975:Antioxidants; D000076122:Disks Large Homolog 4 Protein; D047908:Intracellular Signaling Peptides and Proteins; D020930:MAP Kinase Kinase Kinases; D008565:Membrane Proteins; D048057:Mitogen-Activated Protein Kinase 10; D018092:Kainic Acid Receptors; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; D000097806:GluK2 Kainate Receptor; C501449:Dlg4 protein, rat