title: Compartmentalized oxidative stress in dopaminergic cell death induced by pesticides and complex I inhibitors: distinct roles of superoxide anion and superoxide dismutases.
abstract: The loss of dopaminergic neurons induced by the parkinsonian toxins paraquat, rotenone, and 1-methyl-4-phenylpyridinium (MPP(+)) is associated with oxidative stress. However, controversial reports exist regarding the source/compartmentalization of reactive oxygen species (ROS) generation and its exact role in cell death. We aimed to determine in detail the role of superoxide anion (O2(•-)), oxidative stress, and their subcellular compartmentalization in dopaminergic cell death induced by parkinsonian toxins. Oxidative stress and ROS formation were determined in the cytosol, intermembrane (IMS), and mitochondrial matrix compartments, using dihydroethidine derivatives and the redox sensor roGFP, as well as electron paramagnetic resonance spectroscopy. Paraquat induced an increase in ROS and oxidative stress in both the cytosol and the mitochondrial matrix prior to cell death. MPP(+) and rotenone primarily induced an increase in ROS and oxidative stress in the mitochondrial matrix. No oxidative stress was detected at the level of the IMS. In contrast to previous studies, overexpression of manganese superoxide dismutase (MnSOD) or copper/zinc SOD (CuZnSOD) had no effect on alterations in ROS steady-state levels, lipid peroxidation, loss of mitochondrial membrane potential (ΔΨm), and dopaminergic cell death induced by MPP(+) or rotenone. In contrast, paraquat-induced oxidative stress and cell death were selectively reduced by MnSOD overexpression, but not by CuZnSOD or manganese-porphyrins. However, MnSOD also failed to prevent ΔΨm loss. Finally, paraquat, but not MPP(+) or rotenone, induced the transcriptional activation of the redox-sensitive antioxidant response elements (ARE) and nuclear factor kappa-B (NF-κB). These results demonstrate a selective role of mitochondrial O2(•-) in dopaminergic cell death induced by paraquat, and show that toxicity induced by the complex I inhibitors rotenone and MPP(+) does not depend directly on mitochondrial O2(•-) formation.
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: Humberto
authors.initials: H
authors.lastname: Rodriguez-Rocha
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: Aracely
authors.initials: A
authors.lastname: Garcia-Garcia
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: Chillian
authors.initials: C
authors.lastname: Pickett
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: Sumin
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA.
authors.forename: Jocelyn
authors.initials: J
authors.lastname: Jones
authors.affiliation: Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: Han
authors.initials: H
authors.lastname: Chen
authors.affiliation: Thermo Scientific, Research and Development, Rockford, IL 61105, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Webb
authors.affiliation: Thermo Scientific, Research and Development, Rockford, IL 61105, USA.
authors.forename: Jae
authors.initials: J
authors.lastname: Choi
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; Center for Biotechnology, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; Department of Cellular and Integrative Physiology, University of Nebraska Medical Center, Omaha, NE 68198-5850, USA.
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Zimmerman
authors.affiliation: Redox Biology Center, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA; School of Veterinary Medicine and Biomedical Sciences, University of Nebraska-Lincoln, Lincoln, NE 68583-0905, USA. Electronic address: rfrancocruz2@unl.edu.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Franco
mesh_terms: D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity; D000595:Amino Acid Sequence; D016923:Cell Death / Q000187:drug effects*; D002478:Cells, Cultured; D004578:Electron Spin Resonance Spectroscopy; D042967:Electron Transport Complex I / Q000037:antagonists & inhibitors*; D006801:Humans; D008969:Molecular Sequence Data; D018384:Oxidative Stress; D010575:Pesticides / Q000633:toxicity*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012402:Rotenone / Q000633:toxicity; D013482:Superoxide Dismutase / Q000502:physiology*; D013481:Superoxides / Q000378:metabolism*
chemical_list: D010575:Pesticides; D017382:Reactive Oxygen Species; D012402:Rotenone; D013481:Superoxides; D013482:Superoxide Dismutase; D042967:Electron Transport Complex I; D015655:1-Methyl-4-phenylpyridinium
keywords: CuZnSOD; Environmental; MPP+; MnSOD; Paraquat; Parkinson's disease; Pesticides; Porphyrins; Rotenone; SOD; roGFP