The Alzheimer's Therapeutics Screening Assay: a high-throughput drug-discovery platform utilizing neurons and microglia derived from human induced pluripotent stem cells and Kinetic Image Cytometry

阿尔茨海默病（AD）是痴呆症的最常见原因，随着年龄的增长而增加，困扰着550万人 在美国，没有治愈的方法。第一阶段项目将启动阿尔茨海默氏症治疗药物的开发， 筛选试验（ATSA），其将利用源自人诱导的神经元、小胶质细胞和星形胶质细胞， 多能干细胞一个新的测试系统是迫切需要的，因为以前FDA批准的治疗方法 对于AD具有有限的和暂时的效果，并且自2003年以来没有新药被批准用于AD; 从那时起失败的临床试验说明目前的临床前模型不足以预测AD。作为 淀粉样β肽（A β）斑块在AD患者的大脑中积累，制药公司已经 彻底靶向β-淀粉样蛋白级联途径用于药物发现。然而，虽然其中许多 药物减少斑块，没有一个有效地减缓或预防记忆丧失的临床试验。功能 磁共振（fMRI）研究表明，遗忘型轻度认知障碍（aMCI）患者， AD的前驱症状，在斑块形成之前显示海马神经元过度活跃，表明 神经元钙的失调可能是AD的基础。与此相关的是，小胶质细胞，大脑中的常驻免疫细胞， 在AD中被激活，并分泌谷氨酸和炎性细胞因子，这些细胞因子可能改变神经元钙。 此外，AD的最大遗传风险是载脂蛋白E（APOE 4）的同种型4和蛋白水解酶。 APOE 4的片段引起细胞内钙的失调，并且对神经元和小胶质细胞有毒。为 ATSA将开发这样的方法，其中hiPSC-神经元、-MG和-星形胶质细胞共培养，AD- 相关应力（例如，加入APOE 4片段或APOE 4寡聚物），并监测细胞中APOE 4的改变。 钙（或电压），使用动态图像细胞计数法，一种定量钙的数字显微镜方法 在细胞间的瞬时活动。细胞形态（神经突、突触点）和相关生物标志物 也将被量化。ATSA将是多功能的，第二阶段的目标将包括利用来自患者的iPSC 将纳入代表两种性别的遗传性或散发性AD患者，以进一步询问AD相关 途径。一旦开发完成，ATSA平台将能够每天测试数百种化合物， 确定那些对AD相关压力有有益影响的药物。ATSA将由Vala Sciences销售 Inc为制药公司开发新型AD治疗药物的合同研究，并用于 Vala研究人员的内部药物发现。

Alzheimer’s Disease (AD), the most common cause of dementia, increases with age, afflicts 5.5 million people in the US, and there is no cure. This phase I project will initiate development of the Alzheimer’s Therapeutics Screening Assay (ATSA), which will utilize neurons, microglia, and astrocytes, derived from human induced pluripotent stem cells. A new testing system is desperately needed as previously FDA-approved therapeutics for AD have limited and temporary effects, and no new drug has been approved for AD since 2003; the many failed clinical trials since then illustrate that current preclinical models are not sufficiently predictive for AD. As amyloid beta peptide (A) plaques accumulate in the brains of AD patients, pharmaceutical companies have exhaustively targeted the beta-amyloid cascade pathway for drug-discovery. However, while many of these agents reduced plaques, none effectively slowed or prevented memory loss in clinical trials. Functional magnetic resonance (fMRI) studies show that subjects with amnestic mild cognitive impairment (aMCI), a prodromal symptom of AD, display hyperactive hippocampal neurons prior to plaque formation, suggesting that dysregulation of neuronal calcium may underlie AD. Relatedly, microglia, the resident immune cells of the brain, are activated in AD and secrete glutamate and inflammatory cytokines that may alter neuronal calcium. Furthermore, the greatest genetic risk for AD is isoform 4 of apolipoprotein E (APOE4), and proteolytic fragments of APOE4 cause dysregulation of intracellular calcium and are toxic to neurons and microglia. For the ATSA, methods will be developed in which hiPSC-neurons, -MG, and -astrocytes are cocultured and AD- relevant stresses (e.g., APOE4 fragments or A oligomers) added, and the cells monitored for alterations in calcium (or voltage) using Kinetic Image Cytometry, a digital microscopy method that quantifies calcium transient activity on a cell-by-cell basis. Cell morphology (neurites, synaptic puncta) and relevant biomarkers will also be quantified. The ATSA will be versatile, and phase II goals will include utilizing iPSCs from patients with inherited or sporadic AD, representing both genders, will be incorporated to further interrogate AD-relevant pathways. Once developed, the ATSA platform will enable testing of hundreds of compounds per day to identify those with beneficial effects against AD related stresses. The ATSA will be marketed by Vala Sciences Inc for contract research to pharmaceutical companies developing novel therapeutics for AD, and used for internal drug-discovery by Vala researchers.