Department of Chemical Engineering, Imperial College London, London SW7 2AZ, UK.
Imperial College Centre for Synthetic Biology, Imperial College London, London SW7 2AZ, UK.
Int J Mol Sci. 2021 Nov 5;22(21):12001. doi: 10.3390/ijms222112001.
Accumulation of unfolded/misfolded proteins in neuronal cells perturbs endoplasmic reticulum homeostasis, triggering a stress cascade called unfolded protein response (UPR), markers of which are upregulated in Alzheimer's disease (AD) brain specimens. We measured the UPR dynamic response in three human neuroblastoma cell lines overexpressing the wild-type and two familial AD (FAD)-associated mutant forms of amyloid precursor protein (APP), the Swedish and Swedish-Indiana mutations, using gene expression analysis. The results reveal a differential response to subsequent environmental stress depending on the genetic background, with cells overexpressing the Swedish variant of APP exhibiting the highest global response. We further developed a dynamic mathematical model of the UPR that describes the activation of the three branches of this stress response in response to unfolded protein accumulation. Model-based analysis of the experimental data suggests that the mutant cell lines experienced a higher protein load and subsequent magnitude of transcriptional activation compared to the cells overexpressing wild-type APP, pointing to higher susceptibility of mutation-carrying cells to stress. The model was then used to understand the effect of therapeutic agents salubrinal, lithium, and valproate on signalling through different UPR branches. This study proposes a novel integrated platform to support the development of therapeutics for AD.
蛋白质在神经元细胞中的错误折叠或未折叠的积累扰乱了内质网的稳态，引发了一种被称为未折叠蛋白反应（UPR）的应激级联反应，阿尔茨海默病（AD）脑标本中的这些反应的标志物被上调。我们使用基因表达分析，测量了三种过表达野生型和两种家族性 AD（FAD）相关突变形式的淀粉样前体蛋白（APP）的人神经母细胞瘤细胞系中的 UPR 动态反应，这两种突变形式分别是瑞典突变和瑞典-印第安纳突变。结果显示，根据遗传背景，细胞对后续环境应激的反应存在差异，过表达瑞典突变 APP 的细胞表现出最高的整体反应。我们进一步开发了 UPR 的动态数学模型，该模型描述了在未折叠蛋白积累时，该应激反应的三个分支的激活情况。基于模型的实验数据分析表明，与过表达野生型 APP 的细胞相比，突变细胞系经历了更高的蛋白负荷和随后转录激活的幅度，这表明携带突变的细胞对应激更敏感。然后，该模型被用于了解治疗药物 salubrinal、锂和丙戊酸对不同 UPR 分支信号转导的影响。这项研究提出了一种新的集成平台，以支持 AD 治疗药物的开发。
