Center for Alternative to Animal Testing, Johns Hopkins University, 615 North Wolfe St., Baltimore, MD 21205, United States of America; Department of Biomedical Sciences, University of Lausanne, CH-1015 Lausanne, Switzerland.
Center for Alternative to Animal Testing, Johns Hopkins University, 615 North Wolfe St., Baltimore, MD 21205, United States of America.
Neurobiol Dis. 2022 Jul;169:105719. doi: 10.1016/j.nbd.2022.105719. Epub 2022 Apr 7.
Oxidative stress is caused by an imbalance between the generation and detoxification of reactive oxygen and nitrogen species (ROS/RNS). This imbalance plays an important role in brain aging and age-related neurodegenerative diseases. In the context of Parkinson's disease (PD), the sensitivity of dopaminergic neurons in the substantia nigra pars compacta to oxidative stress is considered a key factor of PD pathogenesis. Here we study the effect of different oxidative stress-inducing compounds (6-OHDA, MPTP or MPP) on the population of dopaminergic neurons in an iPSC-derived human brain 3D model (aka BrainSpheres). Treatment with 6-OHDA, MPTP or MPP at 4 weeks of differentiation disrupted the dopaminergic neuronal phenotype in BrainSpheres at (50, 5000, 1000 μM respectively). 6-OHDA increased ROS production and decreased mitochondrial function most efficiently. It further induced the greatest changes in gene expression and metabolites related to oxidative stress and mitochondrial dysfunction. Co-culturing BrainSpheres with an endothelial barrier using a transwell system allowed the assessment of differential penetration capacities of the tested compounds and the damage they caused in the dopaminergic neurons within the BrainSpheres In conclusion, treatment with compounds known to induce PD-like phenotypes in vivo caused molecular deficits and loss of dopaminergic neurons in the BrainSphere model. This approach therefore recapitulates common animal models of neurodegenerative processes in PD at similarly high doses. The relevance as tool for drug discovery is discussed.
氧化应激是由活性氧和氮物种（ROS/RNS）的产生和解毒之间的失衡引起的。这种失衡在大脑衰老和与年龄相关的神经退行性疾病中起着重要作用。在帕金森病（PD）的背景下，中脑黑质致密部多巴胺能神经元对氧化应激的敏感性被认为是 PD 发病机制的关键因素。在这里，我们研究了不同的氧化应激诱导化合物（6-OHDA、MPTP 或 MPP）对 iPSC 衍生的人脑 3D 模型（又名 BrainSpheres）中多巴胺能神经元群体的影响。在分化的第 4 周用 6-OHDA、MPTP 或 MPP 处理，分别在 50、5000 和 1000μM 时破坏了 BrainSpheres 中的多巴胺能神经元表型。6-OHDA 最有效地增加了 ROS 的产生并降低了线粒体功能。它进一步诱导了与氧化应激和线粒体功能障碍相关的基因表达和代谢物的最大变化。使用 Transwell 系统将 BrainSpheres 与内皮屏障共培养，允许评估测试化合物的差异渗透能力以及它们在 BrainSpheres 内的多巴胺能神经元中造成的损伤。总之，用体内已知诱导 PD 样表型的化合物处理导致了 BrainSphere 模型中分子缺陷和多巴胺能神经元的丧失。因此，这种方法以类似的高剂量重现了 PD 中常见的神经退行性过程的动物模型。讨论了其作为药物发现工具的相关性。
