Effect of Serping1 siRNA Injection on Dopaminergic Cell Reduction in an MPTP-Induced Parkinson's Disease Mouse Model.

Background: Decreased dopaminergic cells and tyrosine hydroxylase (TH) in the substantia nigra (SN) lead to Parkinson's disease (PD); but its cause remains unknown. PD is characterized by α-synuclein (α-syn) accumulation in Lewy bodies; most of which is phosphorylated at Ser129 (pSer129 α-syn). Serping1 is an important gene for controlling blood vessel maintenance; including the process of inflammation. Methods: Increased expression of Serping1 affects dopaminergic cell death in the SN of a chronic PD mouse model induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP); and Serping1 siRNA treatment has a therapeutic effect in this model. Results: We demonstrated that this treatment shows a normal status in the motor ability test and TH level in the SN and striatum. Serping1 siRNA was found to react to decreased Serping1 levels in the SN. In the pSer129-α-syn level of the SN region; Serping1 siRNA had a greater positive effect on PD than N-acetylcysteine by inhibiting pSer129-α-syn formation. Cyclooxygenase-2 and inducible nitric oxide synthase levels were decreased by Serping1 siRNA treatment; thereby indicating its effect on inflammation. Conclusions: Our findings suggest that Serping1 siRNA may represent a potential therapeutic approach for PD; warranting further investigation.