title: Hydrogen peroxide stimulates c-Src-mediated big mitogen-activated protein kinase 1 (BMK1) and the MEF2C signaling pathway in PC12 cells: potential role in cell survival following oxidative insults.
abstract: Reactive oxygen species, generated by reduction-oxidation (redox) reactions, have been recognized as one of the major mediators of ischemia and reperfusion injury in the brain. Reactive oxygen species-induced cerebral events are attributable, in part, to the change in intracellular signaling molecules including mitogen-activated protein (MAP) kinases. Big MAP kinase 1 (BMK1), also known as ERK5, is a newly identified member of the MAP kinase family and has been reported to be sensitive to oxidative stress. In the present study, we examined the effect of H(2)O(2) on BMK1 activity in PC12 cells, and we investigated the pathophysiological implication of BMK1. Findings showed that BMK1 was rapidly and significantly activated by H(2)O(2) in a concentration-dependent manner in PC12 cells. BMK1 activation by H(2)O(2) was inhibited by both PD98059 and U0126, which were reported to inhibit MEK5 as well as MEK1/2. c-Src was suggested to be involved in BMK1 activation from the experiments with herbimycin A and PP2, specific inhibitors of Src family kinases. Transfection of kinase-inactive Src also inhibited H(2)O(2)-induced BMK1 activation. In addition, H(2)O(2) treatment of cells induced an enhancement of DNA binding activity of MEF2C, a downstream transcription factor of BMK1 in PC12 cells. Finally, pretreatment of cells with PD98059 and U0126 resulted in an increase in cell death including apoptosis by H(2)O(2) in ERK1/2 down-regulated cells as well as in intact PC12 cells. These findings suggest that c-Src mediated BMK1 activation by H(2)O(2) may counteract ischemic cellular damage probably through the activation of MEF2C transcription factor.
authors.affiliation: Department of Pharmacology, Pediatrics, Virology, and Clinical Nutrition, the University of Tokushima School of Medicine, Tokushima 770-8503, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Suzaki
authors.forename: Masanori
authors.initials: M
authors.lastname: Yoshizumi
authors.forename: Shoji
authors.initials: S
authors.lastname: Kagami
authors.forename: A Hajime
authors.initials: AH
authors.lastname: Koyama
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Taketani
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Houchi
authors.forename: Koichiro
authors.initials: K
authors.lastname: Tsuchiya
authors.forename: Eiji
authors.initials: E
authors.lastname: Takeda
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Tamaki
mesh_terms: D000818:Animals; D017209:Apoptosis; D002070:Butadienes / Q000494:pharmacology; D000081247:CSK Tyrosine-Protein Kinase; D002470:Cell Survival; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005419:Flavonoids / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D064326:MEF2 Transcription Factors; D048054:Mitogen-Activated Protein Kinase 7; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D018006:Myogenic Regulatory Factors / Q000378:metabolism*; D009570:Nitriles / Q000494:pharmacology; D018384:Oxidative Stress; D016716:PC12 Cells; D011505:Protein-Tyrosine Kinases / Q000502:physiology*; D051381:Rats; D015398:Signal Transduction / Q000187:drug effects*; D019061:src-Family Kinases
chemical_list: D002070:Butadienes; D005419:Flavonoids; D064326:MEF2 Transcription Factors; D018006:Myogenic Regulatory Factors; D009570:Nitriles; C113580:U 0126; D004247:DNA; D006861:Hydrogen Peroxide; D011505:Protein-Tyrosine Kinases; D000081247:CSK Tyrosine-Protein Kinase; D019061:src-Family Kinases; D048054:Mitogen-Activated Protein Kinase 7; D020928:Mitogen-Activated Protein Kinases; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one