反应性氧自由基（ROS）和线粒体功能障碍涉及阿尔茨海默病（AD）的发病机制，该疾病是一种常见的神经退行性疾病，其特征是脑组织中淀粉样前体蛋白（APP）的异常代谢。然而，异常APP导致氧化应激的确切机制仍不清楚。线粒体膜损伤和线粒体呼吸抑制被认为是该疾病进展的原因之一。然而，缺乏能够复制病理特征的适用于人类病理研究的合适模型以及受损的细胞通路对AD研究构成了重大挑战。在本研究中，我们通过诱导患者来源的携带App瑞典突变（APPswe）的皮肤成纤维细胞的多能性，生成了模拟AD的人类脑器官样体，研究了氧化还原调节和线粒体稳态。我们发现APPswe脑器官样体中与AD相关的病理特征呈时间依赖增加，包括升高的Aβ水平，增加的细胞外淀粉样沉积物和增强的tau磷酸化。有趣的是，通过活体成像旋盘共聚焦显微镜技术，我们发现在氧化条件下暴露的APPswe脑器官样体中，线粒体分裂增加，线粒体膜电位显著降低。此外，生活成像条件下使用比值染料显示，在APPswe脑器官样体中，线粒体超氧阴离子和过氧化氢水平选择性增加，并伴随细胞质和线粒体氧化还原蛋白表达受损。我们的结果表明，在APPswe器官样体中，线粒体对氧化条件的敏感性选择性增加，表明APP的异常代谢导致线粒体稳态的特定变化，增加了AD氧化的敏感性。©2023版权所有。Elsevier Inc.发表。

Reactive Oxygen Species (ROS) and mitochondrial dysfunction are implicated in the pathogenesis of Alzheimer's disease (AD), a common neurodegenerative disorder characterized by abnormal metabolism of the amyloid precursor protein (APP) in brain tissue. However, the exact mechanism by which abnormal APP leads to oxidative distress remains unclear. Damage to mitochondrial membrane and inhibition of mitochondrial respiration are thought to contribute to the progression of the disease. However, the lack of suitable human models that replicate pathological features, together with impaired cellular pathways, constitutes a major challenge in AD studies. In this work, we induced pluripotency in patient-derived skin fibroblasts carrying the Swedish mutation in App (APPswe), to generate human brain organoids that model AD, and studied redox regulation and mitochondrial homeostasis. We found time-dependent increases in AD-related pathological hallmarks in APPswe brain organoids, including elevated Aβ levels, increased extracellular amyloid deposits, and enhanced tau phosphorylation. Interestingly, using live-imaging spinning-disk confocal microscopy, we found an increase in mitochondrial fragmentation and a significant loss of mitochondrial membrane potential in APPswe brain organoids when subjected to oxidative conditions. Moreover, ratiometric dyes in a live imaging setting revealed a selective increase in mitochondrial superoxide anion and hydrogen peroxide levels in APPswe brain organoids that were coupled to impairments in cytosolic and mitochondrial redoxin expression. Our results suggest a selective increase in mitochondrial vulnerability to oxidative conditions in APPswe organoids, indicating that the abnormal metabolism of APP leads to specific changes in mitochondrial homeostasis that enhance the vulnerability to oxidation in AD.Copyright © 2023. Published by Elsevier Inc.