Diverging Parkinson’s Disease Pathology between patient-derivedGBAN370S, LRRK2G2019Sand engineeredSNCAA53TiPSC-derived Dopaminergic Neurons

Abstract

Multiple neurodegenerative disorders, including Parkinson’s disease (PD) and Alzheimer’s disease-associated dementia (ADAD), are linked with dopaminergic (DA) neuron death and a resulting reduction in dopamine levels in the brain. DA neuron degeneration and the risk of developing PD is connected to genetic mutations affiliated with lysosomal function and protein degradation. Accessible human cellular models for PD-relevant genetic mutations are needed to investigate mechanisms of DA cell death and define points of therapeutic intervention. Human induced pluripotent stem cell (iPSC)-derived midbrain DA neurons offer a developmentally and physiologically relevantin vitromodel for investigating PD pathogenic mechanisms across genetic backgrounds. In this study, we generated DA neurons using iPSCs from two clinically diagnosed PD patients, one harboring an inheritedGBAN370Smutation and the other a mutation inLRRK2G2019Sand compared pathophysiology against DA neurons from genetically engineeredSNCAA53TiPSCs and its isogenic apparently healthy normal (AHN) iPSCs. Our results present a novel phenotype forGBAN370SandLRRK2G2019Sderived DA neurons, showing that they produced and released significantly more dopamine compared to the AHN andSNCAA53Tmutant DA neurons. All mutant DA neurons developed deficient glucocerebrosidase (GCase) activity, increased mitochondrial stress, aberrant neuronal activity patterns, and increased α-synuclein accumulation. Together these data suggest potentially divergent origins of PD pathogenesis inGBAN370SandLRRK2G2019SDA neurons. In addition, compound screening confirmed that GCase modulators can rescue enzyme activity and impact neural activity across all DA mutant neurons, to varying degrees. These data demonstrate uniquein vitrophenotypes associated with PD and suggest a diversity of underlying mechanisms across different genetic backgrounds. Together, the cell lines used in this study present a valuable tool for new therapeutic discovery.