title: Mitochondrial isocitrate dehydrogenase protects human neuroblastoma SH-SY5Y cells against oxidative stress.
abstract: The neuroprotective effect of mitochondrial isocitrate dehydrogenase (IDPm), an enzyme involved in the reduction of NADP(+) to NADPH and the supply of glutathione (GSH) in mitochondria, was examined using SH-SY5Y cells overexpressing IDPm (S1). S1 cells showed higher NADPH and GSH levels than vector transfectant (V) cells and were more resistant to staurosporine-induced cell death than controls. Staurosporine-induced cytochrome c release, caspase-3 activation, and production of reactive oxygen species (ROS) were significantly attenuated in S1 cells as compared to V cells and reduced by antioxidants, trolox and GSH-ethyl ester (GSH-EE). Staurosporine-induced the release of Mcl-1 from mitochondria that formed a complex with Bim. Mcl-1 was then cleaved to a shortened form in a caspase-3 dependent manner; its release was attenuated far more in S1 than in V cells after staurosporine treatment. Finally, the staurosporine-induced decrease in mitochondrial membrane potential (Deltapsi(m)) was correlated with the time of mitochondrial Mcl-1 release; the loss of Deltapsi(m) was attenuated significantly in S1 cells as compared to that in V cells. These results suggest that the neuroprotective effect of IDPm may result from increases in NADPH and GSH levels in the mitochondria. This, in turn, inhibits mitochondrial ROS production after cytochrome c release, which seems to be mediated through Mcl-1 release.
authors.affiliation: Sogang University, College of Science, Department of Life Science, Seoul, Korea.
authors.forename: Sun J
authors.initials: SJ
authors.lastname: Kim
authors.forename: Tae Y
authors.initials: TY
authors.lastname: Yune
authors.forename: Ching T
authors.initials: CT
authors.lastname: Han
authors.forename: Young C
authors.initials: YC
authors.lastname: Kim
authors.forename: Young J
authors.initials: YJ
authors.lastname: Oh
authors.forename: George J
authors.initials: GJ
authors.lastname: Markelonis
authors.forename: Tae H
authors.initials: TH
authors.lastname: Oh
mesh_terms: D000975:Antioxidants / Q000494:pharmacology; D053148:Caspase 3 / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D053938:DNA Fragmentation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D007211:Indoles; D007521:Isocitrate Dehydrogenase / Q000494:pharmacology*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000201:enzymology* / Q000502:physiology; D009249:NADP / Q000378:metabolism; D009447:Neuroblastoma; D018384:Oxidative Stress / Q000187:drug effects*; D012333:RNA, Messenger / Q000096:biosynthesis; D017382:Reactive Oxygen Species / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D009418:S100 Proteins / Q000378:metabolism; D019311:Staurosporine / Q000494:pharmacology; D014162:Transfection / Q000379:methods
chemical_list: D000975:Antioxidants; D004791:Enzyme Inhibitors; D007211:Indoles; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D009418:S100 Proteins; C007293:DAPI; D009249:NADP; D007521:Isocitrate Dehydrogenase; D053148:Caspase 3; D005978:Glutathione; D019311:Staurosporine