Direct targeting of wild-type glucocerebrosidase by antipsychotic quetiapine improves pathogenic phenotypes in Parkinson's disease models

Current treatments for Parkinson's disease (PD) provide only symptomatic relief, with no disease modifying therapies identified to date. Repurposing FDA-approved drugs to treat PD could significantly shorten the time needed for and reduce the costs of drug development compared with conventional approaches. We developed an efficient strategy to screen for modulators of beta-glucocerebrosidase (GCase), a lysosomal enzyme that exhibits decreased activity in patients with PD, leading to accumulation of the substrate glucosylceramide and oxidized dopamine and alpha-synuclein, which contribute to PD pathogenesis. Using a GCase fluorescent probe and affinity based fluorescence polarization assay, we screened 1280 structurally diverse, bioactive, and cell-permeable FDA-approved drugs and found that the antipsychotic quetiapine bound GCase with high affinity. Moreover, quetiapine treatment of induced pluripotent stem cell-derived (iPSC-derived) dopaminergic neurons from patients carrying mutations in GBA1 or LRRK2 led to increased wild-type GCase protein levels and activity and partially lowered accumulation of oxidized dopamine, glucosylceramide, and alpha-synuclein. Similarly, quetiapine led to activation of wild-type GCase and reduction of alpha-synuclein in a GBA mutant mouse model (Gba1D409V/+ mice). Together, these results suggest that repurposing quetiapine as a modulator of GCase may be beneficial for patients with PD exhibiting decreased GCase activity.

Automated summary

Current treatments for Parkinson's disease only provide symptomatic relief, but repurposing FDA-approved drugs such as quetiapine as a modulator of GCase activity shows potential for improving the condition of PD patients with decreased GCase activity. This study developed an efficient screening strategy for identifying drugs to treat PD and found that quetiapine treatment could increase levels and activity of wild-type GCase and reduce the accumulation of oxidized dopamine, glucosylceramide, and alpha-synuclein in PD patients.