title: Blockade of the translocation and activation of mitogen-activated protein kinase kinase 4 (MKK4) signaling attenuates neuronal damage during later ischemia-reperfusion.
abstract: Mitogen-activated protein kinase kinase 4 (MKK4), as an upstream activator of c-Jun NH(2)-terminal kinase (JNK), plays a critical role in response to cellular stresses and pro-inflammatory cytokines. In this study, we investigated the subcellular localization and activation of MKK4 in response to global cerebral ischemia. Our results indicated that MKK4 had two activation peaks in both the cytosol and the nucleus, and translocated from the cytosol to the nucleus at 30 min and 6 h of reperfusion. We also detected the interaction of JNK-interacting protein 3 (JIP3) and MKK4, which reached a maximum at 6 h of reperfusion. To elucidate the mechanism of translocation and activation, we administered N-acetylcysteine, an antioxidant reagent, and a glutamate receptor 6 C-terminus-containing peptide (Tat-GluR6-9c) to rats. The data showed that N-acetylcysteine limited the translocation and activation at 30 min of reperfusion; however, the peptide perturbed the subcellular localization and activation at 6 h of reperfusion, and subsequently provided a protective role against delayed neuronal cell death. Taken together, these results demonstrate that the translocation and activation of MKK4 during early reperfusion are closely associated with reactive oxygen species, whereas, at late reperfusion, MKK4 activation may be involved in brain ischemic injury.
authors.affiliation: Research Center for Biochemistry and Molecular Biology, Xuzhou Medical College, Xuzhou, China.
authors.forename: Qing-Xiu
authors.initials: QX
authors.lastname: Zhang
authors.forename: Dong-Sheng
authors.initials: DS
authors.lastname: Pei
authors.forename: Qiu-Hua
authors.initials: QH
authors.lastname: Guan
authors.forename: Ya-Feng
authors.initials: YF
authors.lastname: Sun
authors.forename: Xiao-Mei
authors.initials: XM
authors.lastname: Liu
authors.forename: Guang-Yi
authors.initials: GY
authors.lastname: Zhang
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western / Q000379:methods; D003553:Cystine / Q000031:analogs & derivatives / Q000494:pharmacology; D004195:Disease Models, Animal; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007150:Immunohistochemistry / Q000379:methods; D047468:Immunoprecipitation / Q000379:methods; D048670:MAP Kinase Kinase 4 / Q000378:metabolism*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000473:pathology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013347:Subcellular Fractions / Q000187:drug effects / Q000378:metabolism; D013997:Time Factors
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D003553:Cystine; D048670:MAP Kinase Kinase 4; C030905:N-monoacetylcystine