Pathogenic mechanisms of ABCA7 in Alzheimer's disease

项目总结/摘要 马约杰克逊维尔 ATP结合盒转运蛋白A7（ABCA 7）基因变异与发生糖尿病的风险密切相关。 迟发性阿尔茨海默病（AD），这是老年痴呆症的主要原因。ABCA 7属于 ABC转运蛋白家族调节脂质和其它亲脂性分子在细胞内的分布 膜。ABCA 7在脑中表达丰富，特别是在神经元和小胶质细胞中。一个更好的 了解ABCA 7的细胞类型特异性功能对于解决疾病机制至关重要。 由于ABCA 7的功能缺失变异最近被证明会增加AD风险，我们 假设ABCA 7缺乏通过不同的途径促进AD的发生和进展， 每种细胞类型的特定途径。鉴于大脑中ABCA 7水平在神经元中最高， 小胶质细胞，该提案特别关注这两种细胞类型中的ABCA 7介导的通路。我们将 在对照组和常规组中进行靶向神经元和小胶质细胞的单细胞型转录组分析 ABCA 7敲除小鼠。这种基于系统的方法应该识别新的ABCA 7调节基因/网络 调节大脑内环境稳定和AD相关通路。通过这种方法获得的结果将是 不仅在小鼠原代培养物中得到验证，而且在来自诱导多能干细胞的人细胞中也得到验证。 细胞（iPSC）。使用规则间隔短回文重复序列（CRISPR）/Cas9基因编辑 技术，ABCA 7敲除和单倍不足iPSC系将产生模型ABCA 7 丧失功能的变体。此外，我们将研究ABCA 7在神经元和小胶质细胞中的功能， 通过Cre ER-loxP系统的独特的他莫昔芬诱导型、细胞类型特异性ABCA 7敲除小鼠， 没有淀粉样蛋白病理学的背景。我们提出两个具体目标。在目标1中，我们将定义单元格 在神经元和小胶质细胞中的类型特异性ABCA 7调节通路。在目标2中，我们将研究 使用条件性小鼠模型，ABCA 7的功能影响AD相关通路。总的来说，这些研究 应该提供新的机制洞察如何ABCA 7功能的丧失在神经元或小胶质细胞的影响， AD的风险，并有可能定义新的AD治疗靶点。

PROJECT SUMMARY/ABSTRACT MAYO CLINIC JACKSONVILLE ATP-binding cassette transporter A7 (ABCA7) gene variants are strongly associated with the risk of developing late-onset Alzheimer's disease (AD), which is the leading cause of dementia in the elderly. ABCA7 belongs to the ABC transporter family regulating distribution of lipids and other lipophilic molecules across cellular membranes. ABCA7 expression is abundant in the brain, particularly in neurons and microglia. Thus, a better understanding of the cell type-specific functions of ABCA7 is crucial for addressing the disease mechanisms. Because loss-of-function variants in ABCA7 have recently been demonstrated to increase AD risk, we hypothesize that ABCA7 deficiency contributes to the development and progression of AD via different pathways specific to each cell type. Given that ABCA7 levels in the brain are the highest in neurons followed by microglia, this proposal specifically focuses on the ABCA7-mediated pathways in these two cell types. We will perform single-cell type transcriptome analyses targeting neurons and microglia in control and conventional ABCA7 knockout mice. This systems-based approach should identify novel ABCA7-regulated genes/networks that modulate brain homeostasis and AD-related pathways. The results obtained through this approach will be validated not only in mouse primary cultures but also in human cells derived from induced pluripotent stem cells (iPSCs). Using Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)/Cas9 gene editing technology, ABCA7 knockout and haploinsufficient iPSC lines will be generated that model ABCA7 loss-of-function variants. Furthermore, we will investigate ABCA7 functions in neurons and microglia using unique tamoxifen-inducible, cell type-specific ABCA7 knockout mice through the Cre ER-loxP system with or without the background of amyloid pathology. We propose two specific aims. In Aim 1, we will define cell type-specific ABCA7-regulated pathways in neurons and microglia. In Aim 2, we will examine how the loss of function of ABCA7 impacts AD-related pathways using conditional mouse models. Collectively, these studies should provide novel mechanistic insight into how the loss of ABCA7 function in neurons or microglia impacts the risk for AD and has the potential to define novel targets for AD therapy.