title: Determining the oxidation states of manganese in PC12 and nerve growth factor-induced PC12 cells.
abstract: Excessive brain Mn can produce toxicity with symptoms resembling parkinsonism. This syndrome, called "manganism," correlates with loss of dopamine in the striatum and cell death in the striatum and globus pallidus. A common hypothesis is that cell damage in Mn toxicity is caused by oxidation of important cell components by Mn3+. Determination of the amount of Mn3+ present, under a range of conditions, in neuronal cells and brain mitochondria represents an important step in evaluating the "damage through oxidation by Mn3+ hypothesis." In an earlier paper we used X-ray absorption near-edge structure (XANES) spectroscopy to determine the amount of Mn2+ and Mn3+ in brain mitochondria under a range of conditions. Here we extend the study to investigate the evidence for formation of Mn3+ through oxidation of Mn2+ by ROS in PC12 cells and in PC12 cells induced with nerve growth factor (NGF) to display a phenotype more like that of neurons. Although the results suggest that very small amounts of Mn3+ might be present at low Mn levels, probably in Mn superoxide dismutase, Mn3+ is not stabilized by complex formation in these cells and therefore does not accumulate to detectable amounts.
authors.affiliation: Department of Biochemistry and Biophysics, University of Rochester School of Medicine and Dentistry, 575 Elmwood Avenue, Rochester, NY 14642, USA.
authors.forename: Karlene K
authors.initials: KK
authors.lastname: Gunter
authors.forename: Michael
authors.initials: M
authors.lastname: Aschner
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Miller
authors.forename: Roman
authors.initials: R
authors.lastname: Eliseev
authors.forename: Jason
authors.initials: J
authors.lastname: Salter
authors.forename: Katie
authors.initials: K
authors.lastname: Anderson
authors.forename: Sean
authors.initials: S
authors.lastname: Hammond
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Gunter
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D008345:Manganese / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D020932:Nerve Growth Factor / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D016716:PC12 Cells; D051381:Rats; D017382:Reactive Oxygen Species; D013052:Spectrometry, X-Ray Emission; D013054:Spectrophotometry, Atomic / Q000379:methods; D013482:Superoxide Dismutase / Q000378:metabolism; D013997:Time Factors
chemical_list: D016877:Oxidants; D017382:Reactive Oxygen Species; D008345:Manganese; D020932:Nerve Growth Factor; D013482:Superoxide Dismutase; D010100:Oxygen