The Effects On Apoptosis Of Parkinson's Disease Cell Model By Knock-down Pael-R Gene Expression Through RNAi

Parkinson's disease(PD) is a second common neurodegenerative disease. It's important pathological chatacter is apoptosis of dopaminergic neurons in substantia nigra.The causation leading to apoptosis of dopaminergic neurons is still obscure,but generally considered that it may result from an environmental factor and/or a genetic causation.At present there are 13 virulence genes of this disease are known, 5 of them, Parkin , DJ-1,α-synuclein, PINK and LRRK2,are considered contribute to the familial Parkinson's disease. Further researches indicated that the deposition of the paraprotein,leading by the damage of the ubiquitin-proteasomal system(UPS), may play an important role in the death of dopaminergic neuron. Thus Parkin became an important gene in PD because the protein taken as E3 ligating enzyme in UPS, parkin protein and it's poisonous sustrates become a hot point in reseachs.The main substrates of Parkin includeα-synuclein, Synphilin-1, Pael-R, CDCrel-1 and cyclinE. Pael-R is the autoploid of endothelin receptor B, its mRNA mainly distribute in striatum and substantia nigra. If over-express Pael-R, its protein will not be degradation through UPS and deposite in cell, as a result cell will death. As the E3 ligating enzyme in UPS, Parkin gene deletion lead to Pael-R,a-Sp22 et al deposite in cell and induce cell apoptosis. This may be the important pathogenic mechanism for autosomal recessive juvenile Parkinsonism(AR-JP).At the same time, the envionmental toxins could also lead to apoptosis of dopaminergic neurons ,this may be another important pathogenisis in PD. As an generally used pesticide, Rotenone has reappeared PD characteristic in cell model and animal model, but its mechanism is unknown.In this research, we use PC12 cells induced by NGF to become dopaminergic neuron substituting cells, and then use RNAi to establish the Parkin gene knock-down cell model, meanwhile use Rotenone to establish the envionmental toxin cell model. After those, reduce the Pael-R gene expression by RNAi in the two cell models and observe the change of apoptosis by Hoechst 33258,MTT and flow cytometer.The results indicated, apoptosis was very obvious in Parkin gene knock-down cell model. If reduced the Pael-R gene expression in this model, apoptosis rate will decline. Moreover, apoptosis is also obvious in the Rotenone cell model,reduced the Pael-R gene expression have no apparente influence on apoptosis of dopaminergic neurons . This result indicated that Pael-R may not play an role in the process of Rotenone induced dopaminergic neurons apoptosis,and reducing the Pael-R gene expression could not protect dopaminergic neurons from Rotenone induced apoptosis.