Constitutive nuclear accumulation of endogenous alpha-synuclein in mice causes motor impairment and cortical dysfunction, independent of protein aggregation.

ABSTRACT: A growing body of evidence suggests that nuclear alpha-synuclein (aSyn) plays a role in the pathogenesis of Parkinson’s disease (PD). However, this question has been difficult to address as controlling the localization of aSyn in experimental systems often requires protein overexpression, which affects its aggregation propensity. To overcome this, we engineered Snca-NLS mice which localize endogenous aSyn to the nucleus. We characterized these mice on a behavioral, histological, and biochemical level to determine whether the increase of nuclear aSyn is sufficient to elicit PD-like phenotypes. SncaNLS mice exhibit age-dependent motor deficits and altered gastrointestinal function. We found that these phenotypes were not linked to aSyn aggregation or phosphorylation. Through histological analyses, we observed motor cortex atrophy in the absence of midbrain dopaminergic neurodegeneration. We sampled cortical proteomes of Snca-NLS mice and controls to determine the molecular underpinnings of these pathologies. Interestingly, we found several dysregulated proteins involved in dopaminergic signalling, including Darpp32, Pde10a, and Gng7, which we further confirmed was decreased in cortical samples of the Snca-NLS mice compared to controls. These results suggest that chronic endogenous nuclear aSyn can elicit toxic phenotypes in mice, independent of its aggregation. This model raises key questions related to the mechanism of aSyn toxicity in PD and provides a new model to study an underappreciated aspect of PD pathogenesis.

INSTRUMENT(S):

ORGANISM(S): Mus Musculus (mouse)

TISSUE(S): Brain

SUBMITTER: Haley Geertsma  

LAB HEAD: Maxime Rousseaux

PROVIDER: PXD032065 | Pride | 2022-04-06

REPOSITORIES: Pride