Prolyl oligopeptidase inhibition attenuates the toxicity of a proteasomal inhibitor, lactacystin, in the alpha-synuclein overexpressing cell culture

•Decreased proteasomal activities have been connected to Parkinson’s disease.•Lactacystin increased alpha-synuclein aggregation in a cell culture.•Prolyl oligopeptidase inhibition by KYP-2047 attenuated lactacystin toxicity.•KYP-2047 decreased alpha-synuclein oligomers and enhanced autophagy.