Lewy Body-like Inclusions in Human Midbrain Organoids Carrying Glucocerebrosidase and alpha-Synuclein Mutations

Objective We utilized human midbrain-like organoids (hMLOs) generated from human pluripotent stem cells carrying glucocerebrosidase gene (GBA1) and alpha-synuclein (alpha-syn; SNCA) perturbations to investigate genotype-to-phenotype relationships in Parkinson disease, with the particular aim of recapitulating alpha-syn- and Lewy body-related pathologies and the process of neurodegeneration in the hMLO model. Methods We generated and characterized hMLOs from GBA1(-/-) and SNCA overexpressing isogenic embryonic stem cells and also generated Lewy body-like inclusions in GBA1/SNCA dual perturbation hMLOs and conduritol-b-epoxide-treated SNCA triplication hMLOs. Results We identified for the first time that the loss of glucocerebrosidase, coupled with wild-type alpha-syn overexpression, results in a substantial accumulation of detergent-resistant, beta-sheet-rich alpha-syn aggregates and Lewy body-like inclusions in hMLOs. These Lewy body-like inclusions exhibit a spherically symmetric morphology with an eosinophilic core, containing alpha-syn with ubiquitin, and can also be formed in Parkinson disease patient-derived hMLOs. We also demonstrate that impaired glucocerebrosidase function promotes the formation of Lewy body-like inclusions in hMLOs derived from patients carrying the SNCA triplication. Interpretation Taken together, the data indicate that our hMLOs harboring 2 major risk factors (glucocerebrosidase deficiency and wild-type alpha-syn overproduction) of Parkinson disease provide a tractable model to further elucidate the underlying mechanisms for progressive Lewy body formation. ANN NEUROL 2021

Automated summary

Utilizing human midbrain-like organoids (hMLOs), researchers successfully recapitulated the pathologies of Parkinson disease, demonstrating the formation of Lewy body-like structures due to glucocerebrosidase deficiency and wild-type alpha-synuclein overexpression. This provides a promising model for further elucidating the mechanisms of progressive Lewy body formation in Parkinson disease.