title: Down-regulation Cdc42 attenuates neuronal apoptosis through inhibiting MLK3/JNK3 cascade during ischemic reperfusion in rat hippocampus.
abstract: JNK signaling pathway is activated and involved in the selective neuronal death in the hippocampal CA1 subfield following cerebral ischemia. However, little is known about upstream partner controlling the pathway. Here we reported that ischemia/reperfusion significantly elevated Cdc42 activity, enhanced assembly of the Cdc42-MLK3 complex and activation of JNK pathway. Most importantly, knock-down endogenous Cdc42 selectively suppressed the MLK3/MKK7/JNK3 cascade, and subsequently blocked the phosphorylation of c-Jun and FasL expression. Meanwhile, Bcl-2 was inactivated and the release of cytochrome c was diminished. These alterations eventually perturbed the caspase-3 activation as well as post-ischemic neuronal cell death. Taken together, our findings strongly suggest that Cdc42 serves as an upstream activator and modulates JNK-mediated apoptosis machinery in vivo, which ultimately results in neuronal apoptosis via nuclear and non-nuclear pathways. Thus, Cdc42 may be a potential therapeutic target in ischemic brain injury.
authors.affiliation: Research Center for Biochemistry and Molecular Biology, Jiangsu Key Laboratory of Brain Disease Bioinformation, Xuzhou Medical College, Xuzhou, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Pei
authors.forename: Quan-Guang
authors.initials: QG
authors.lastname: Zhang
authors.forename: Guang-Yi
authors.initials: GY
authors.lastname: Zhang
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002545:Brain Ischemia / Q000139:chemically induced / Q000201:enzymology; D053148:Caspase 3 / Q000378:metabolism; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors*; D008297:Male; D048057:Mitogen-Activated Protein Kinase 10 / Q000037:antagonists & inhibitors*; D009474:Neurons / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D010766:Phosphorylation / Q000187:drug effects; D011485:Protein Binding / Q000187:drug effects; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015424:Reperfusion; D020764:cdc42 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000172:deficiency / Q000235:genetics*; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11
chemical_list: D053148:Caspase 3; D045304:Cytochromes c; D020930:MAP Kinase Kinase Kinases; D048057:Mitogen-Activated Protein Kinase 10; D016376:Oligonucleotides, Antisense; D019253:Proto-Oncogene Proteins c-bcl-2; D020764:cdc42 GTP-Binding Protein; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11