Adaptive changes in autophagy after UPS impairment in Parkinson＇s disease  

作　　者：Yu-fei SHEN Yu TANG Xiao-jie ZHANG Kai-xing HUANG Wei-dong LE 

机构地区：[1]Institute of Neurology, Ruijin Hospital, Jiao Tong University School of Medicine, Shanghai 200025, China, [2]The Key Laboratory of StemCell Biology, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences & Shanghai JiaoTong University School of Medicine, Shanghai 200025, China

出　　处：《Acta Pharmacologica Sinica》2013年第5期667-673,共7页中国药理学报（英文版）

摘　　要：Ubiquitin-proteasome system （UPS） and autophagosome-lysosome pathway （ALP） are the most important machineries respon- sible for protein degradation in Parkinson＇s disease （PD）. The aim of this study is to investigate the adaptive alterations in autophagy upon proteasome inhibition in dopaminergic neurons in vitro and in vivo. Methods： Human dopaminergic neuroblastoma SH-SYSY cells were treated with the proteasome inhibitor lactacystin （5 pmol/L） for 5, 12, or 24 h. The expression of autophagy-related proteins in the cells was detected with immunoblotting. UPS-impaired mouse mode of PD was established by microinjection of lactacystin （2 pg） into the left hemisphere of C57BL/6 mice that were sacrificed 2 or 4 weeks later. The midbrain tissues were dissected to assess alterations in autophagy using immunofluorescence, immunoblotting and electron microscopy assays. Results： Both in SH-SY5Y cells and in the midbrain of UPS-impaired mouse model of PD, treatment with lactacystin significantly increased the expression levels of LC3-1/II and Beclin 1, and reduced the levels of p-mTOR, mTOR and p62/SQSTM1. Furthermore, lactacystin treatment in UPS-impaired mouse model of PD caused significant loss of TH-positive neurons in the substantia nigra, and dramatically increased the number of autophagosomes in the left TH-positive neurons. Conclusion： Inhibition of UPS by lactacystin in dopaminergic neurons activates another protein degradation system, the ALP, which includes both the mTOR signaling pathway and Beclin 1-associated pathway.Ubiquitin-proteasome system （UPS） and autophagosome-lysosome pathway （ALP） are the most important machineries respon- sible for protein degradation in Parkinson＇s disease （PD）. The aim of this study is to investigate the adaptive alterations in autophagy upon proteasome inhibition in dopaminergic neurons in vitro and in vivo. Methods： Human dopaminergic neuroblastoma SH-SYSY cells were treated with the proteasome inhibitor lactacystin （5 pmol/L） for 5, 12, or 24 h. The expression of autophagy-related proteins in the cells was detected with immunoblotting. UPS-impaired mouse mode of PD was established by microinjection of lactacystin （2 pg） into the left hemisphere of C57BL/6 mice that were sacrificed 2 or 4 weeks later. The midbrain tissues were dissected to assess alterations in autophagy using immunofluorescence, immunoblotting and electron microscopy assays. Results： Both in SH-SY5Y cells and in the midbrain of UPS-impaired mouse model of PD, treatment with lactacystin significantly increased the expression levels of LC3-1/II and Beclin 1, and reduced the levels of p-mTOR, mTOR and p62/SQSTM1. Furthermore, lactacystin treatment in UPS-impaired mouse model of PD caused significant loss of TH-positive neurons in the substantia nigra, and dramatically increased the number of autophagosomes in the left TH-positive neurons. Conclusion： Inhibition of UPS by lactacystin in dopaminergic neurons activates another protein degradation system, the ALP, which includes both the mTOR signaling pathway and Beclin 1-associated pathway.

关 键 词：proteasome inhibitor LACTACYSTIN ubiquitin-proteasome system dopaminergic neuron Parkinson＇s disease autophagy-lysosomal pathway AUTOPHAGOSOME mTOR Beclin 1 

分 类 号：Q593.2[生物学—生物化学] TN86[电子电信—信息与通信工程]