Fibrillary aggregation of α-synuclein in Lewy body inclusions and nigrostriatal dopaminergic neuron degeneration define Parkinson’s disease neuropathology. Mutations in GBA1, encoding glucocerebrosidase, are the most frequent genetic risk factor for Parkinson’s disease. However, the lack of reliable experimental models able to reproduce key neuropathological signatures has hampered the clarification of the link between mutant glucocerebrosidase and Parkinson’s disease pathology. Here, we describe an innovative protocol for the generation of human induced pluripotent stem cell-derived midbrain organoids containing dopaminergic neurons with nigral identity that reproduce characteristics of advanced maturation. When applied to patients with GBA1-related Parkinson’s disease, this method enabled the differentiation of midbrain organoids recapitulating dopaminergic neuron loss and fundamental features of Lewy body pathology observed in human brains, including the generation of α-synuclein fibrillary aggregates with seeding activity that also propagate pathology in healthy control organoids. Still, we observed that the retention of mutant glucocerebrosidase in the endoplasmic reticulum and increased levels of its substrate glucosylceramide are determinants of α-synuclein aggregation into Lewy body-like inclusions. Consistently, the reduction of glucocerebrosidase activity accelerated α-synuclein pathology by promoting fibrillary α-synuclein deposition. Finally, we demonstrated the efficacy of ambroxol and GZ667161 – two modulators of the glucocerebrosidase pathway in clinical development for the treatment of GBA1-related Parkinson’s disease – in reducing α-synuclein pathology in this model, supporting the use of midbrain organoids as a relevant pre-clinical platform for investigational drug screening.

中文翻译：

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患者来源的 GBA1 帕金森病中脑类器官的路易病理形成


路易体包涵体中 α-突触核蛋白的纤维聚集和黑质纹状体多巴胺能神经元变性定义了帕金森病神经病理学。编码葡萄糖脑苷脂酶的 GBA1 突变是帕金森病最常见的遗传风险因素。然而，缺乏能够重现关键神经病理学特征的可靠实验模型阻碍了阐明突变葡萄糖脑苷脂酶与帕金森病病理学之间联系的阐明。在这里，我们描述了一种创新方案，用于生成人诱导的多能干细胞衍生的中脑类器官，其中包含具有黑质身份的多巴胺能神经元，这些神经元再现了高级成熟的特征。当应用于 GBA1 相关帕金森病患者时，该方法能够区分中脑类器官，概括多巴胺能神经元丢失和在人脑中观察到的路易体病理学的基本特征，包括产生具有播种活性的 α-突触核蛋白纤维聚集体，这些聚集体也在健康的对照类器官中传播病理学。尽管如此，我们观察到突变的葡糖脑苷脂酶在内质网中的保留及其底物葡糖神经酰胺水平的增加是 α-突触核蛋白聚集成路易体样包涵体的决定因素。始终如一，葡萄糖脑苷脂酶活性的降低通过促进纤维 α-突触核蛋白沉积来加速 α-突触核蛋白病理。 最后，我们证明了氨溴索和 GZ667161（葡萄糖脑苷脂酶通路的两种调节剂）在治疗 GBA1 相关帕金森病的临床开发中的疗效——在该模型中减少 α-突触核蛋白病理学，支持使用中脑类器官作为研究药物筛选的相关临床前平台。