What species of alpha-synuclein should be targeted for development of PD therapies?

Current theory suggests a possible toxic oligomeric or aggregated form of alpha-synuclein as the trigger for subsequent neurodegeneration in PD, but definitive evidence for this is lacking. Proposed therapeutic approaches focus predominately on breaking up aggregates, or attempt to reduce alpha-synuclein protein levels, either by inhibiting production (e.g, via RNA interference) or enhancing protein turnover. Given current understanding of alpha-synuclein, are these the best approaches for targeting alpha-synuclein therapeutically? What studies are needed to clarify the ideal alpha-synuclein target?