title: 3-nitropropionic acid-induced hydrogen peroxide, mitochondrial DNA damage, and cell death are attenuated by Bcl-2 overexpression in PC12 cells.
abstract: 3-nitropropionic acid (3-NPA), a complex II inhibitor of the electron transport chain, causes Huntington disease-like symptoms after administration into animals. However, primary mechanisms of cell death are not clearly understood. This study tested the hypothesis that 3-NPA leads to the generation of reactive oxygen species (ROS), mitochondrial DNA damage, and loss of mitochondrial function. Amplex red and horseradish peroxidase were used to accurately measure the amount of H2O2, and showed that PC12 cells treated with 3-NPA (4 mM) lead to the production of hydrogen peroxide (1 nmol/10(6) cells/h). This amount of 3-NPA also leads to a rapid decline of ATP levels. There was time- and dose-dependent mitochondrial DNA damage following 3-NPA treatment. Overexpression of the proto-oncogene bcl-2 protects cells from apoptosis induced by various stimuli. Overexpression of Bcl-2 leads to almost threefold higher levels of ATP and also decreased the 3-NPA-mediated induction of hydrogen peroxide by over 50%. Bcl-2-overexpressing PC12 cells were also protected from mitochondrial DNA damage. These data show that ROS production followed by mitochondrial DNA damage is the primary event in 3-NPA toxicity, and Bcl-2 protects PC12 cells from 3-NPA toxicity by preventing mitochondrial DNA damage.
authors.affiliation: Laboratory of Molecular Genetics, National Institute of Environmental and Health Sciences, National Institutes of Health, 111 Alexander Drive, P.O. Box 12233, Research Triangle Park, NC 27709, USA.
authors.forename: Bhaskar S
authors.initials: BS
authors.lastname: Mandavilli
authors.forename: Istvan
authors.initials: I
authors.lastname: Boldogh
authors.forename: Bennett
authors.initials: B
authors.lastname: Van Houten
mesh_terms: D000818:Animals; D002452:Cell Count / Q000379:methods; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003292:Convulsants / Q000494:pharmacology; D004249:DNA Damage / Q000187:drug effects*; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000378:metabolism; D004097:Dihydrotachysterol / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry / Q000379:methods; D015870:Gene Expression / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects; D006861:Hydrogen Peroxide / Q000378:metabolism*; D009574:Nitro Compounds; D016716:PC12 Cells; D011422:Propionates / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism* / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013997:Time Factors
chemical_list: D003292:Convulsants; D004272:DNA, Mitochondrial; D009574:Nitro Compounds; D011422:Propionates; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D006861:Hydrogen Peroxide; C015392:3-nitropropionic acid; D004097:Dihydrotachysterol