Downregulation of parkin damages antioxidant defenses and enhances proteasome inhibition-induced toxicity in PC12 cells.
Loss-of-function mutations in the parkin gene have recently been shown to be responsible for autosomal recessive juvenile Parkinsonism. However, the exact mechanism of pathogenesis remains unclear. This study explores the effect of Parkin downregulation on dopaminergic cells in Parkinson's disease. We generated small interfering RNA plasmids that target the parkin gene and transfected them into PC12 cells to mimic in vivo loss-of-function. We found that these small plasmids were able to effectively inhibit endogenous Parkin expression in PC12 cells. Downregulation of Parkin decreased the amount of glutathione and superoxide dismutase activity without affecting the amount of malondialdehyde. Moreover, Parkin knockdown rendered PC12 cells more susceptible to cell death induced by the proteasome inhibitor lactacystin. These results indicate that downregulation of Parkin may damage the antioxidation defenses of dopaminergic cells and increase their susceptibility to proteasome inhibitor-induced toxicity.
Department of Neurology & Neuroscience Institute, Ruijin Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China.
Hui
H
Yang
Hai-Yan
HY
Zhou
Biao
B
Li
Guo-Zhong
GZ
Niu
Sheng-Di
SD
Chen
D000111:Acetylcysteine / Q000031:analogs & derivatives / Q000633:toxicity; D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D016716:PC12 Cells; D046988:Proteasome Endopeptidase Complex / Q000096:biosynthesis / Q000633:toxicity; D061988:Proteasome Inhibitors; D051381:Rats; D044767:Ubiquitin-Protein Ligases / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics
D000975:Antioxidants; D061988:Proteasome Inhibitors; C067713:lactacystin; D044767:Ubiquitin-Protein Ligases; C111567:parkin protein; D046988:Proteasome Endopeptidase Complex; D000111:Acetylcysteine