DNA methylation signatures of Alzheimer's disease in aged astrocytes

项目总结 与年龄相关的神经疾病，如阿尔茨海默病(AD)，影响着全球数百万人，并构成 给医疗系统带来负担。虽然大多数研究集中在阿尔茨海默病的神经元变性上，但有大量的 有证据表明，非神经细胞，如星形胶质细胞，在疾病进展中起着重要作用。重要的是 迟发性阿尔茨海默病的主要危险因素APOE在星形胶质细胞中高表达，是导致 淀粉样β蛋白相关的细胞毒性，进而影响星形胶质细胞的功能。而病因学 疾病相关星形胶质细胞中AD的基础尚不清楚，如DNA甲基化(DNaM)等表观遗传修饰， 它们都是健康衰老和神经退行性变的已知贡献者，可能会发挥作用。 虽然诱导多能干细胞(IPSC)衍生的AD模型提供了有价值的分子洞察力 作为疾病的基础，它们缺乏固有的能力来概括与年龄相关的DNA甲基化，转录， 以及与这种晚期、年龄相关的大脑疾病高度相关的细胞表型。研究表明 成纤维细胞向神经元的直接转化保留了与年龄相关的甲基组和转录 模式。因此，我们开发了一种有效的成人成纤维细胞来源的直接转化策略 诱导星形胶质细胞(FDIA)，我们建议将其验证为一个捕捉年龄的“盘中年龄”模型。 相关的DNA甲基化、基因表达和细胞表型。使用此模型，我们还旨在 阐明与年龄和疾病相关的dNaM变化与星形胶质细胞功能的关系 以下目标：1)建立与年龄相关的dNaM和转录特征以及细胞表型 2)评价dNaM与星形胶质细胞功能的关系并阐明它们的作用。 到AD风险。 通过这项研究，我们希望有效地开发出一种人类星形胶质细胞的“盘中年龄”模型， 准确捕获与年龄相关的dNaM和转录签名，我们将对其进行评估 在阿尔茨海默病的神经炎症和神经退行性变过程中的作用。我们的研究是独一无二的，它验证了 一个老化的星形胶质细胞模型(FDIA)，以及在AD的星形细胞dNaM和转录信号的评估中， 从而提高了我们对包括AD在内的与年龄相关的脑部疾病的分子病因学的理解。

PROJECT SUMMARY Age-related neurological disorders like Alzheimer’s disease (AD) affect millions worldwide and pose a major burden to the healthcare system. While most studies focus on neuronal degeneration in AD, there is substantial evidence that non-neuronal cells, such as astrocytes, play an important role in disease progression. Importantly, a major risk factor for late-onset AD, APOE, is highly expressed in astrocytes and is a major contributor to amyloid-beta-associated cellular toxicity, which in turn, dysregulates astrocytic functionality. While the etiological basis for AD in disease-associated astrocytes is unclear, epigenetic modifications like DNA methylation (DNAm), which are known contributors to both healthy aging and neurodegeneration, are likely to play a role. While induced pluripotent stem cell (iPSC)-derived models of AD provide valuable insight into the molecular basis for the disease, they lack the inherent ability to recapitulate age-associated DNA methylation, transcription, and cellular phenotypes that are highly relevant in such late-stage, age-associated brain disorders. Studies show that direct conversion of fibroblasts to neurons retains such age-associated methylomic and transcriptomic patterns. We therefore developed an efficient direct conversion strategy of adult human fibroblast-derived induced-astrocytes (FDIAs), which we propose to validate as an “age-in-a-dish” model that captures age- associated DNA methylation, gene expression, and cellular phenotypes. Using this model, we also aim to elucidate the association of age- and disease-related changes in DNAm to astrocyte functionality using the following aims: 1) establish age-associated DNAm and transcriptional signatures and cellular phenotypes of FDIAs; and 2) evaluate the relationship between DNAm and astrocytic function and elucidate their contribution to AD risk. Through this research, we expect to efficiently develop an ‘age-in-a-dish’ model of human astrocytes that accurately captures age-associated DNAm and transcriptional signatures, which we will be assessed for their role in neuroinflammatory and neurodegenerative processes in AD. Our study is unique in both the validation of an aged astrocyte model (FDIAs), and in the evaluation of astrocytic DNAm and transcriptional signatures in AD, thus improving our understanding of the molecular etiology of age-related brain disorders, including AD.