title: Significant neuroprotection against ischemic brain injury by inhibition of the MEK1 protein kinase in mice: exploration of potential mechanism associated with apoptosis.
abstract: MEK1/2 is a serine/threonine protein kinase that phosphorylates and activates extracellular signal-responsive kinase (ERK)1/2. In the present study we explored the role of MEK1/2 in ischemic brain injury using a selective MEK1/2 inhibitor, SL327, in mice. C57BL/6 mice were subjected to a 30-min occlusion of the middle cerebral artery (MCAO) followed by reperfusion. Western blot analysis demonstrated the immediate activation of MEK/ERK after reperfusion (within the first 10 min) in the ischemic brain; this activation was dose dependently blocked by SL327 (10-100 mg/kg, i.p.). A single dose of SL327 (100 mg/kg) administered 15 min before or 25 min after the onset of ischemia resulted in 63.6% (n = 18, p < 0.001) and 50.7% (n = 18, p < 0.01) reduction in infarct size, respectively, compared with vehicle-treated mice. Similarly, SL327 significantly reduced neurological deficits 1 to 3 days after reperfusion (n = 12, p < 0.01). The salutary effect of SL327-induced neuroprotection was independent of mitochondrial cytochrome c release or caspase-8-mediated apoptosis; however, SL327 markedly suppressed the levels of active caspase-3 and DNA fragmentation (as a measure of apoptosis) after ischemia/reperfusion. Our data suggest that the inhibition of MEK1/2 results in neuroprotection from reperfusion injury and that this protection may be associated with the reduction in apoptosis.
authors.affiliation: Department of Cardiovascular Sciences, Bristol-Myers Squibb Company, Wilmington, Delaware 19880-0400, USA. wangxk2000@yahoo.com
authors.forename: Xinkang
authors.initials: X
authors.lastname: Wang
authors.forename: Hugh
authors.initials: H
authors.lastname: Wang
authors.forename: Lin
authors.initials: L
authors.lastname: Xu
authors.forename: Dennis J
authors.initials: DJ
authors.lastname: Rozanski
authors.forename: Taku
authors.initials: T
authors.lastname: Sugawara
authors.forename: Pak H
authors.initials: PH
authors.lastname: Chan
authors.forename: James M
authors.initials: JM
authors.lastname: Trzaskos
authors.forename: Giora Z
authors.initials: GZ
authors.lastname: Feuerstein
mesh_terms: D000607:Aminoacetonitrile / Q000031:analogs & derivatives; D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D020520:Brain Infarction / Q000188:drug therapy / Q000473:pathology; D002545:Brain Ischemia / Q000188:drug therapy* / Q000473:pathology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020244:Infarction, Middle Cerebral Artery / Q000188:drug therapy / Q000473:pathology; D048369:MAP Kinase Kinase 1; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D010766:Phosphorylation; D004856:Postural Balance / Q000187:drug effects; D011480:Protease Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors*; D015427:Reperfusion Injury / Q000188:drug therapy / Q000473:pathology
chemical_list: D003574:Cytochrome c Group; D004791:Enzyme Inhibitors; D018696:Neuroprotective Agents; D011480:Protease Inhibitors; C424127:SL 327; D000607:Aminoacetonitrile; D017346:Protein Serine-Threonine Kinases; D020928:Mitogen-Activated Protein Kinases; D048369:MAP Kinase Kinase 1; C482127:Map2k1 protein, mouse; D020929:Mitogen-Activated Protein Kinase Kinases; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases