title: Effect of lysosomal and ubiquitin-proteasome system dysfunction on the abnormal aggregation of α-synuclein in PC12 cells.
abstract: The aim of this study was to investigate the effect of lysosomal and ubiquitin-proteasome system dysfunction on the abnormal aggregation of α-synuclein, and to analyze its role in the pathogenesis of Parkinson's disease (PD). PC12 cells subjected to nerve growth factor-induced differentiation were used as the cell model to study the dopaminergic neurons, and the lysosomal and proteasomal inhibitors trans-epoxysuccinyl-L-leucylamido-(4-guanidino) butane (E64) and, respectively, were used exclusively and in combination to treat the PC12 cells. The viability and metabolic state of the cells was assessed using the MTT assay; flow cytometry was used to measure the rate of cell apoptosis; and the double immunofluorescence method was applied to observe the formation of thioflavin S- and α-synuclein protein-positive aggregates and inclusion bodies in the PC12 cells. In addition, the Hoechst 33258 staining method was used to observe the apoptosis of the α-synuclein protein and thioflavin-S double-labeled cells. Following the administration of the lysosomal and proteasomal pathway inhibitors, the cell viability decreased in a concentration-dependent manner and the cell apoptosis rate increased. The proportion of PC12 cells with α-synuclein protein-positive aggregates and inclusion bodies in the E64 group was 7.94%, compared with 20.33 and 36.77% in the lactacystin and combination treatment groups, respectively. Statistical analysis indicated that the number of inclusion body-positive cells in the treatment groups was significantly higher than that in the control group (3.78%) (P<0.05). Apoptosis was evident in the double-positive cells with α-synuclein protein-positive inclusion bodies (17.29±1.54%). In conclusion, lysosomal and proteasomal dysfunction may play an important role in the pathogenesis of PD through the induction of abnormal α-synuclein protein aggregation in dopaminergic neurons.
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Runqing
authors.initials: R
authors.lastname: Wang
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Henan Provincial People's Hospital, Zhengzhou, Henan 450003, P.R. China.
authors.forename: Jiewen
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Liu
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Meiying
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Jiangtao
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Juan
authors.initials: J
authors.lastname: Lv
authors.affiliation: Department of Neurology, Zhengzhou Central Hospital Affiliated to Zhengzhou University, Zhengzhou, Henan 450007, P.R. China.
authors.forename: Yanan
authors.initials: Y
authors.lastname: Li
keywords: PC12 cell; lysosomes; ubiquitin-proteasome; α-synuclein