Viral vector-mediated overexpression of α-synuclein as a progressive model of Parkinson's disease.

The discovery of the role of α-synuclein in the pathogenesis of Parkinson's disease (PD) has opened new possibilities for the development of more authentic models of Parkinson's disease. Recombinant adeno-associated virus (AAV) and lentivirus (LV) vectors are efficient tools for expression of genes locally in subsets of neurons in the brain and can be used to express human wild-type or mutated α-synuclein selectively in midbrain dopamine neurons. Using this approach, it is possible to trigger extensive PD-like cellular and axonal pathologies in the nigrostriatal projection, involving abnormal protein aggregation, neuronal dysfunction, and cell death that develop progressively over time. Targeted overexpression of human α-synuclein in midbrain dopamine neurons, using AAV vectors, reproduces many of the characteristic features of the human disease and provides, for the first time, a model of progressive PD that can be applied to both rodents and primates.

Ulusoy A ，Decressac M ，Kirik D ，Björklund A ... -  《-》

Progressive neurodegenerative and behavioural changes induced by AAV-mediated overexpression of α-synuclein in midbrain dopamine neurons.

Parkinson's disease (PD) is characterised by the progressive loss of nigral dopamine neurons and the presence of synucleinopathy. Overexpression of α-synuclein in vivo using viral vectors has opened interesting possibilities to model PD-like pathology in rodents. However, the attempts made so far have failed to show a consistent behavioural phenotype and pronounced dopamine neurodegeneration. Using a more efficient adeno-associated viral (AAV) vector construct, which includes a WPRE enhancer element and uses the neuron-specific synapsin-1 promoter to drive the expression of human wild-type α-synuclein, we have now been able to achieve increased levels of α-synuclein in the transduced midbrain dopamine neurons sufficient to induce profound deficits in motor function, accompanied by reduced expression of proteins involved in dopamine neurotransmission and a time-dependent loss of nigral dopamine neurons, that develop progressively over 2-4 months after vector injection. As in human PD, nigral cell loss was preceded by degenerative changes in striatal axons and terminals, and the appearance of α-synuclein positive inclusions in dystrophic axons and dendrites, supporting the idea that α-synuclein-induced pathology hits the axons and terminals first and later progresses to involve also the cell bodies. The time-course of changes seen in the AAV-α-synuclein treated animals defines distinct stages of disease progression that matches the pre-symptomatic, early symptomatic, and advanced stages seen in PD patients. This model provides new interesting possibilities for studies of stage-specific pathologic mechanisms and identification of targets for disease-modifying therapeutic interventions linked to early or late stages of the disease.

Decressac M ，Mattsson B ，Lundblad M ，Weikop P ，Björklund A ... -  《-》

Overexpression of alpha-synuclein in rat substantia nigra results in loss of dopaminergic neurons, phosphorylation of alpha-synuclein and activation of caspase-9: resemblance to pathogenetic changes in Parkinson's disease.

Yamada M ，Iwatsubo T ，Mizuno Y ，Mochizuki H ... -  《JOURNAL OF NEUROCHEMISTRY》

alpha -Synucleinopathy and selective dopaminergic neuron loss in a rat lentiviral-based model of Parkinson's disease.

Lo Bianco C ，Ridet JL ，Schneider BL ，Deglon N ，Aebischer P ... -  《-》

Down-regulation of alpha-synuclein expression can rescue dopaminergic cells from cell death in the substantia nigra of Parkinson's disease rat model.

Hayashita-Kinoh H ，Yamada M ，Yokota T ，Mizuno Y ，Mochizuki H ... -  《BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS》