Curated Optogenetic Publication Database

Abstract: Presynaptic accumulation of misfolded α-synuclein (α-syn) and altered synaptic transmission are considered early events in the pathogenesis of Parkinson's disease (PD), suggesting a potential causal link between these two events. However, the mechanisms by which α-syn aggregation induces synaptic dysfunction and the subsequent progressive neurodegeneration remain elusive. In the present study we leveraged the high temporal resolution of the Light-Inducible Protein Aggregation (LIPA) system in vivo and in human dopaminergic neurons to explore the early sequence of α-syn-induced pathological events leading to synaptopathy. We observed that nigrostriatal axonal transport and presynaptic accumulation of α-syn aggregates altered the activity of different neuronal populations in the mouse striatum. The results of histological and metabolite analyses show that presynaptic accumulation of α-syn induced a shift in the activation pattern of D1- and D2-expressing striatal medium spiny neurons, caused an increase in the size and density of dopaminergic synapses, and disrupted striatal dopamine signaling. Altogether, our findings reveal that the accumulation of α-syn in dopaminergic terminals triggered early presynaptic impairments, which subsequently altered striatal neuronal activity. Our study provides new insights into the molecular mechanisms underlying early synaptopathy in PD.

Abstract: Alpha-synuclein (α-syn) aggregation is a defining feature of Parkinson's disease (PD) and related synucleinopathies. Despite significant research efforts focused on understanding α-syn aggregation mechanisms, the early stages of this process remain elusive, largely due to limitations in experimental tools that lack the temporal resolution to capture these dynamic events. Here, we introduce UltraID-LIPA, an innovative platform that combines the light-inducible protein aggregation (LIPA) system with the UltraID proximity-dependent biotinylation assay to identify α-syn-interacting proteins and uncover key mechanisms driving its oligomerization. UltraID-LIPA successfully identified 38 α-syn-interacting proteins, including both established and previously unreported candidates, highlighting the accuracy and robustness of the approach. Notably, a strong interaction with endolysosomal and membrane-associated proteins was observed, supporting the hypothesis that interactions with membrane-bound organelles are pivotal in the early stages of α-syn aggregation. This powerful platform provides new insights into dynamic protein aggregation events, enhancing our understanding of synucleinopathies and other proteinopathies.

Abstract: Studying Parkinson's disease (PD) is complex due to a lack of cellular models mimicking key aspects of protein pathology. Here, we present a protocol for inducing and monitoring α-synuclein aggregation in living cells using optogenetics. We describe steps for plasmid transduction, biochemical validation, immunocytochemistry, and live-cell confocal imaging. These induced aggregates fulfill the cardinal features of authentic protein inclusions observed in PD-diseased brains and offer a tool to study the role of protein aggregation in neurodegeneration. For complete details on the use and execution of this protocol, please refer to Bérard et al.1.