1-methyl-4-phenylpyridinium-induced alterations of glutathione status in immortalized rat dopaminergic neurons.
Decreased glutathione levels associated with increased oxidative stress are a hallmark of numerous neurodegenerative diseases, including Parkinson's disease. GSH is an important molecule that serves as an anti-oxidant and is also a major determinant of cellular redox environment. Previous studies have demonstrated that neurotoxins can cause changes in reduced and oxidized GSH levels; however, information regarding steady state levels remains unexplored. The goal of this study was to characterize changes in cellular GSH levels and its regulatory enzymes in a dopaminergic cell line (N27) following treatment with the Parkinsonian toxin, 1-methyl-4-phenylpyridinium (MPP(+)). Cellular GSH levels were initially significantly decreased 12 h after treatment, but subsequently recovered to values greater than controls by 24 h. However, oxidized glutathione (GSSG) levels were increased 24 h following treatment, concomitant with a decrease in GSH/GSSG ratio prior to cell death. In accordance with these changes, ROS levels were also increased, confirming the presence of oxidative stress. Decreased enzymatic activities of glutathione reductase and glutamate-cysteine ligase by 20-25% were observed at early time points and partly account for changes in GSH levels after MPP(+) exposure. Additionally, glutathione peroxidase activity was increased 24 h following treatment. MPP(+) treatment was not associated with increased efflux of glutathione to the medium. These data further elucidate the mechanisms underlying GSH depletion in response to the Parkinsonian toxin, MPP(+).
Drechsel
Derek A
DA
Department of Pharmaceutical Sciences, School of Pharmacy, University of Colorado at Denver and Health Sciences Center, 4200 East Ninth Avenue, Box C238, Denver, CO 80262, USA.
Liang
Li-Ping
LP
Patel
Manisha
M
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D000818:Animals; D053801:Capillary Electrochromatography; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry / Q000379:methods; D005721:Glutamate-Cysteine Ligase / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D019803:Glutathione Disulfide / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D009498:Neurotoxins / Q000633:toxicity; D018384:Oxidative Stress / Q000187:drug effects; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism; D013997:Time Factors; D014116:Toxicology / Q000379:methods; D005723:gamma-Glutamyltransferase / Q000378:metabolism
D009498:Neurotoxins; D017382:Reactive Oxygen Species; D007770:L-Lactate Dehydrogenase; D005979:Glutathione Peroxidase; D005980:Glutathione Reductase; D005723:gamma-Glutamyltransferase; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione; D015655:1-Methyl-4-phenylpyridinium; D019803:Glutathione Disulfide; D004298:Dopamine