Reduction of a-synuclein aggregates by PIKfyve inhibition via TFEB-mediated lysosomal biogenesis in a Parkinson disease model

Parkinson disease is a neurodegenerative disorder characterised by impairment of motor function, and is associated with a progressive accumulation of insoluble aggregates of misfolded alpha-synuclein. In the present study, we exploited the SH-SY5Y cell model overexpressing a pro-aggregation form of alpha-synuclein to investigate the efficacy of PIKfyve-mediated lysosomal biogenesis, through TFEB, as potential target for Parkinson therapy. To investigate this, we exploited high-content imaging along with enzymatic assays to follow the progression of lysosomal biogenesis, lysosomal function and alpha-synuclein accumulation. The cellular model exploited in this study recapitulated important elements of the biochemical phenotype observed in Parkinson patient-derived neurons, including synuclein aggregates and impaired glucocerebrosidase (GCase) function. PIKfyve inhibition by YM201636 resulted in a lysosomal-dependant reduction of alpha-synuclein aggregates as early as 24 hours post-treatment. The mechanism of action of YM201636 was shown to be TFEB-mediated, with an increase in TFEB in the nuclei which subsequently resulted in increased lysosomal markers LAMP1 and GCase. PIKfyve inhibtion efficacy was also tested in differentiated SH-SY5Y cells, exhibiting a neuron-like morphology. In these cells, YM201636 also significantly reduced alpha-synuclein aggregates and increased TFEB nuclear presence. These findings suggest that PIKfyve inhibition could be exploited as therapeutic target for Parkinson disease.