The mechanism of sirtuin 2-mediated exacerbation of alpha-synuclein toxicity in models of Parkinson disease

Abstract

Sirtuin genes have been associated with aging and are known to affect multiple cellular pathways. Sirtuin 2 was previously shown to modulate proteotoxicity associated with ageassociated neurodegenerative disorders such as Alzheimer and Parkinson disease (PD). However, the precise molecular mechanisms involved remain unclear. Here, we provide mechanistic insight into the interplay between sirtuin 2 and alpha-synuclein, the major component of the pathognomonic protein inclusions in PD and other synucleinopathies. We found that alpha-synuclein is acetylated on lysines 6 and 10 and that these residues are deacetylated by sirtuin 2. Genetic manipulation of sirtuin 2 levels in vitro and in vivo modulates the levels of alpha-synuclein acetylation, its aggregation, and autophagy. Strikingly, mutants blocking acetylation exacerbate alpha-synuclein toxicity in vivo, in the substantia nigra of rats. Our study identifies alpha-synuclein acetylation as a key regulatory mechanism governing alpha-synuclein aggregation and toxicity, demonstrating the potential therapeutic value of sirtuin 2 inhibition in synucleinopathies.