Differential pathological dynamics triggered by distinct Parkinson patient-derived α-synuclein extracts in nonhuman primates

The presence of α-synuclein (α-syn) aggregates, such as Lewy bodies in patients with Parkinson’s disease (PD), contributes to dopaminergic cell death. Injection of PD patient–derived α-syn in nonhuman primates has illustrated the exquisite vulnerability of primate dopaminergic neurons. Here, we aimed to elucidate the temporal and spatial pathological changes induced by two distinct α-syn pathogenic structures, having large or small sizes. To unravel the underlying molecular pathways, we conducted a proteomic analysis of the putamen and the entorhinal cortex, two brain regions carrying notable α-syn pathology. We demonstrate that distinct assemblies of α-syn aggregates drive unique pathogenic changes that ultimately result in a comparable extent of nigrostriatal degeneration at the level of nigral dopaminergic neuron cell bodies and striatal dopaminergic terminals. More broadly, our findings identify pathogenic trajectories associated with large or small α-syn aggregates, suggesting the existence of several possible concomitant pathogenic routes in PD.