Role of autophagy and proteasome degradation pathways in apoptosis of PC12 cells transfected with A53T α-synuclein

Abstract

Objective To explore the specific role of autophagy and ubiquitin-proteasome pathway in apoptosis, specific protease inhibitor and (or) macroautophagy inhibitors.Methods The stimulators were selected to work on the pheochromocytoma (PC12) cell lines transfected with human mutant α-synuclein (A53T).Cell activity and apeptosis rate were detected by MTT law and flow cytometry.NO energy, heat shock protein 70 (Hsp70) and Caspase-3 expression were determined in cell culture.Results A53T cell survival rate significantly decreased 24 hours after handling with the protease inhibitor (100 nmol/L) and (or) autophagy inhibitors 3-MA (10 mmol/L, A =0.23±0.01,0.19±0.01 and 0.17±0.01 respectively; P <0.05) compared with the control group (A =0.32±0.06).Cell survival rate was significantly higher than the other drug group after 24 hours handling with autophagy stimulators (A =0.44±0.08).Compared with the control group or autophagy stimulator of rapamycin (0.2 μg/ml) group (1.55%±1.15%), A53T cells apeptosis percentage rate was significantly higher after treated with proteasome inhibitor and macroautophagy inhibitors 24 hours (4.74%±0.91%, 4.59%±1.18% and 5.40%±1.75%respectively, P <0.05); and a slight decrease with stimulators.Protein Hsp70 and NO were significantly higher in proteasome inhibitor groups than the control group.But in antophagy inhibitor and stimulator group, NO and Hsp70 protein was similar to the control group.Conclusion The inhibition of macroautophagy and proteasome can promote apoptosis.Inhibiting or stimulating autophagy has less impact on Hsp70 and NO than proteasome pathway. Key words: Parkinson diseases; alpha-Synuclein; Autophagy; Proteasome endopeptidase complex; Apoptosis