α-synuclein overexpression model

Abstract

Objectives. To elucidate the role of α-synuclein in the pathogenesis of Parkinson's disease (PD), both human α-synuclein transgenic mice and targeted overexpression of human α-synuclein in rat substantia nigra (SN) by viral vector-based methods have been studied, however little is known about the pathogenetic changes of dopaminergic neuron loss. Therefore, it is necessary to address whether the pathogenetic changes in the brains of patients with PD are recapitulated in these models. Methods and results. We used the recombinant adeno-associated viral (rAAV) vector system for human α-synuclein gene transfer to rat SN and observed approximately 50% loss of dopaminergic neurons in SN at 13 weeks after infection. In the slower progression of neurodegeneration, we identified several important features in common with the pathogenesis of PD, such as phosphorylation of α-synuclein at Ser129 and activation of caspase-9. Both findings were also evident in cortical tissues overexpressing α-synuclein via rAAV. Conclusions. Our results indicate that overexpression of α-synuclein via rAAV apparently recapitulates several important features of brains with PD and dementia with Lewy bodies (DLB), and thus α-synucleinopathy described here is likely to be an ideal model for the study of the pathogenesis of PD and DLB. This model is also useful for the gene therapy research. © Springer-Verlag 2006.