1-Methyl-4-phenyl-pyridinium time-dependently alters expressions of oxoguanine glycosylase 1 and xeroderma pigmentosum group F protein in PC12 cells.
OBJECTIVE
To determine if DNA excision repair enzymes oxoguanine glycosylase 1 (OGG1) and xeroderma pigmentosum group F protein (XPF) are involved in the pathogenesis of Parkinson's disease (PD) in a cell model.


METHODS
PC12 cells were treated with 1-Methyl-4-phenylpyridine ion (MPP(+)) for various periods of time to induce oxidative DNA damage. MTT assay was used to determine cell viability. Immunocytochemistry with antibody against 8-hydroxy-2'-deoxyguanosine (8-oxodG) was used to evaluate oxidative DNA damage. Immunoblotting was used to detect the protein levels of OGG1 and XPF.


RESULTS
MPP(+) treatment (1 mmol/L) for 18 h and 24 h reduced cell viability to 78.6% and 70.3% of the control, respectively, in a time-dependent way. MPP(+) increased the immunoreactivity of 8-oxodG in the cytoplasm at 3 h and in the nucleus at 24 h of treatment. With the treatment of MPP(+), the expression of OGG1 was significantly increased at 1 h, reaching a peak at 3 h, and then it was decreased at 24 h, as compared to that with vehicle treatment. The same effect was exerted on XPF level, except that the XPF level reached a peak at 18 h of MPP(+) treatment. Moreover, the maximally-increased protein level of OGG1 by MPP(+) was approximately 2-fold higher than that of XPF.


CONCLUSIONS
MPP(+) treatment could time-dependently induce increases in OGG1 and XPF expressions in PC12 cells. Also, this study indicates that the base and nucleotide excision repair pathways may be compensatory activated in the early stage of pathogenesis in the cells after MPP(+) treatment.
Liu
Hong-Mei
HM
Department of Neurobiology, Shanghai Medical College, Fudan University, Shanghai 200032, China.
Yang
Shan-Zheng
SZ
Sun
Feng-Yan
FY
D015655:1-Methyl-4-phenylpyridinium / Q000633:toxicity*; D000080242:8-Hydroxy-2'-Deoxyguanosine; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004249:DNA Damage / Q000187:drug effects; D045647:DNA Glycosylases / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003849:Deoxyguanosine / Q000031:analogs & derivatives / Q000378:metabolism; D007150:Immunohistochemistry; D016877:Oxidants / Q000633:toxicity*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D016716:PC12 Cells; D010300:Parkinson Disease; D051381:Rats; D013997:Time Factors
D004268:DNA-Binding Proteins; D016877:Oxidants; C095888:xeroderma pigmentosum group F protein; D000080242:8-Hydroxy-2'-Deoxyguanosine; D045647:DNA Glycosylases; C483741:OGG1 protein, rat; D003849:Deoxyguanosine; D015655:1-Methyl-4-phenylpyridinium