Abstract: Abstract: Objective To explore the role for PINK1 in the regulation of dopamine biosynthesis. Methods The dopaminergic MN9D cell was used as a cell model for the present study. PINK1 gene was knockdown by RNAi technique. The dopamine (DA) level, mRNA and protein expression level of (tyrosine hydroxylase, TH) and (dopa decarboxylase, DDC) were then detected by HPLC with electrochemical detection, real-time RT-PCR or Western blots 48h later, respectively. The association between PINK1 and TH was observed with Co-immunoprecipitation and immunohistochemistry. Results When PINK1 was silenced, DA content was 5.356±0.536ng/ml significantly lower than the control group of 11.63 ± 1.559ng/ml (p<0.05), TH mRNA and protein expression were 0.3713±0.1403 and 0.1956 ±0.06212 significantly lower than that of control group 1.009±0.1528 and 0.3861±0.04455(p<0.05),DDC mRNA and protein expression were 0.3963±0.1241 and 0.1492 ±0.02940 significantly lower than that of control group1.009±0.1528 and 0.3861±0.04455, respectively.(p<0.05) Conclusion PINK1 had a regulatory effect on dopamine biosynthesis, which is caused by its influence on TH and DDC, two important enzymes for DA synthesis.

Key words: Key word: PINK1, RNA interference, tyrosine hydroxylase, MN9D cells