Department of Biomedical Science, CHA Stem Cell Institute, CHA University, Seongnam-si, Korea.
Neuroscience Center, Samsung Medical Center, Seoul, Korea.
Cell Prolif. 2020 Apr;53(4):e12798. doi: 10.1111/cpr.12798. Epub 2020 Mar 25.
Alzheimer's disease (AD) is the most common neurodegenerative disease which is characterized by the formation of amyloid beta (Aβ) plaques and neurofibrillary tangles. These abnormal proteins induce disturbance in mitochondrial dynamics and defect in autophagy system. Since presenilin-1 (PS1) is a core component in γ-secretase complex, the mutations of PS1 gene cause the interference of γ-secretase activity and lead to the increased Aβ secretion. We aimed to characterize the patient-specific induced pluripotent stem cell (iPSC) line carrying PS1-S170F mutation. Furthermore, we tested whether disease-modifying drug can reduce AD pathology in the AD iPSC-derived neurons.
Mononuclear cells (MNCs) were isolated freshly from the peripheral blood of an autosomal dominant AD (ADAD) patient carrying presenilin-1 (PS1) mutation (Ser170Phe; PS1-S170F) and a cognitively normal control. We generated induced pluripotent stem cell (iPSC) lines, which were differentiated into functional cortical neurons. Then, we measured the markers indicative of AD pathogenesis using immunocytochemistry and Western blot. We also investigated the mitochondrial dynamics in the AD iPSC-derived neurons using Mito-tracker.
We observed that both extracellular and intracellular Aβ levels were dramatically increased in the PS1-S170F iPSC-derived neurons, compared with the control iPSC-derived neurons. Furthermore, PS1-S170F iPSC-derived neurons showed high expression levels of p-Tau, which were detected both in the soma and neurites. The mitochondrial velocity in the PS1-S170F iPSC-derived neurons was much reduced, compared with that of the control. We also found a significant decrease of fusion-related protein Mfn1 (membrane proteins mitofusin 1) and an increase of fission-related protein DRP1 (dynamin-related protein 1) in the PS1-S170F iPSC-derived neurons. We further observed the defects of autophagy-related clearance in the PS1-S170F iPSC-derived neurons. Finally, we demonstrated the levels of Aβ and p-Tau can be dramatically reduced by the treatment of LY-2886721, a BACE1 inhibitor.
Taken together, we have established and characterized the pathological features of an AD patient carrying PS1-S170F mutation using iPSC technology, which will be the first case on this mutation and this iPSC line will serve as a useful resource for studying AD pathogenesis and drug screening in the future.
阿尔茨海默病（AD）是最常见的神经退行性疾病，其特征是淀粉样β（Aβ）斑块和神经原纤维缠结的形成。这些异常蛋白导致线粒体动力学紊乱和自噬系统缺陷。由于早老素 1（PS1）是γ-分泌酶复合物的核心组成部分，PS1 基因突变会干扰γ-分泌酶的活性，导致 Aβ分泌增加。我们旨在描述携带 PS1-S170F 突变的患者特异性诱导多能干细胞（iPSC）系的特征。此外，我们测试了疾病修饰药物是否可以减少 AD iPSC 衍生神经元中的 AD 病理学。
从携带早老素 1（PS1）突变（Ser170Phe；PS1-S170F）和认知正常对照的常染色体显性 AD（ADAD）患者的外周血中新鲜分离单核细胞（MNC）。我们生成诱导多能干细胞（iPSC）系，将其分化为功能性皮质神经元。然后，我们使用免疫细胞化学和 Western blot 测量指示 AD 发病机制的标志物。我们还使用 Mito-tracker 研究了 AD iPSC 衍生神经元中的线粒体动力学。
与对照 iPSC 衍生神经元相比，PS1-S170F iPSC 衍生神经元中外源和细胞内 Aβ 水平均显著增加。此外，PS1-S170F iPSC 衍生神经元中 p-Tau 的表达水平较高，在体和突起中均有检测到。PS1-S170F iPSC 衍生神经元的线粒体速度明显降低，与对照相比。我们还发现 PS1-S170F iPSC 衍生神经元中的融合相关蛋白 Mfn1（膜蛋白线粒体融合蛋白 1）减少和分裂相关蛋白 DRP1（dynamin-related protein 1）增加。我们进一步观察到 PS1-S170F iPSC 衍生神经元中的自噬相关清除缺陷。最后，我们证明了 BACE1 抑制剂 LY-2886721 的治疗可显著降低 Aβ 和 p-Tau 的水平。
总之，我们使用 iPSC 技术建立并描述了携带 PS1-S170F 突变的 AD 患者的病理特征，这将是该突变的首例病例，该 iPSC 系将成为未来研究 AD 发病机制和药物筛选的有用资源。
