Abstract: Objective To investigate the mechanism of inhibition of tyrosine hydroxylase(TH) expression in α-Syn-transfected dopaminergic neuronal cells,specifically whether or not α-Syn inhibits TH activity through affecting histone deacetylase(HDAC).Methods Histone deacetylase activity assay kit was used to measure the difference of HDAC activity in transfected cells and control cells.After treatment with the inhibitor of HDAC(TSA) in transfected cells,the expression of TH was determined by RT-PCR and Western-blot,respectively.Results The HDAC activity in the transfected cells was significantly higher than in the control cells.After inhibiting the HDAC activity in transfected cells by TSA to the level of control cells,the expression of TH was up-regulated both at mRNA and protein levels.Conclusion These results suggested that HDAC was involved in the mechanism of inhibition of tyrosine hydroxylase expression in α-Syn-transfected dopaminergic neuronal cells.

Key words: α-Synuclein, tyrosine hydroxylase, histone deacetylase, Parkinson disease