title: Reactive oxygen species and p38 mitogen-activated protein kinase activate Bax to induce mitochondrial cytochrome c release and apoptosis in response to malonate.
abstract: Malonate, an inhibitor of mitochondrial complex II, is a widely used toxin to study neurodegeneration in Huntington's disease and ischemic stroke. We have shown previously that malonate increased reactive oxygen species (ROS) production in human SH-SY5Y neuroblastoma cells, leading to oxidative stress, cytochrome c release, and apoptotic cell death. Expression of a green fluorescent protein-Bax fusion protein in SH-SY5Y neuroblastoma cells demonstrated a Bax redistribution from the cytosol to mitochondria after 12 to 24 h of malonate treatment that coincided with mitochondrial potential collapse and chromatin condensation. Inhibition of Bax translocation using furosemide, as well as Bax gene deletion, afforded significant protection against malonate-induced apoptosis. Further experiments revealed that malonate induced a prominent increase in the level of activated p38 mitogen-activated protein (MAP) kinase and that treatment with the p38 MAP kinase inhibitor SKF86002 potently blocked malonate-induced Bax translocation and apoptosis. Treatment with vitamin E diminished ROS production, reduced the activation status of p38 MAP kinase, inhibited Bax translocation, and protected against malonate-induced apoptosis. Our data suggest that malonate-induced ROS production and subsequent p38 MAP kinase activation mediates the activation of the pro-apoptotic Bax protein to induce mitochondrial membrane permeabilization and neuronal apoptosis.
authors.affiliation: Grupo de Neurofarmacología, Departamento de Ciencias Médicas, Facultad de Medicina, Universidad Castilla-La Mancha, 02006, Albacete, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Gomez-Lazaro
authors.forename: M F
authors.initials: MF
authors.lastname: Galindo
authors.forename: R M
authors.initials: RM
authors.lastname: Melero-Fernandez de Mera
authors.forename: F J
authors.initials: FJ
authors.lastname: Fernandez-Gómez
authors.forename: C G
authors.initials: CG
authors.lastname: Concannon
authors.forename: M F
authors.initials: MF
authors.lastname: Segura
authors.forename: J X
authors.initials: JX
authors.lastname: Comella
authors.forename: J H M
authors.initials: JH
authors.lastname: Prehn
authors.forename: J
authors.initials: J
authors.lastname: Jordan
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D045304:Cytochromes c / Q000378:metabolism*; D008314:Malonates / Q000494:pharmacology*; D008315:Malondialdehyde / Q000032:analysis; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000502:physiology*
chemical_list: D008314:Malonates; D017382:Reactive Oxygen Species; D051028:bcl-2-Associated X Protein; D008315:Malondialdehyde; D045304:Cytochromes c; C030290:malonic acid; D048051:p38 Mitogen-Activated Protein Kinases