MODULATION OF APP METABOLISM BY X11ALPHA/MINT-1

X11ALPHA/MINT-1 对 APP 代谢的调节

• 批准号: 6933390
• 负责人: RAYMOND SCOTT TURNER
• 金额: $ 12.5万
• 依托单位: UNIVERSITY OF MICHIGAN AT ANN ARBOR
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-06-01 至 2010-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6933390
• 关键词: Alzheimer' s disease; amyloid proteins; brain metabolism; cell line; gene expression; genetically modified animals; human tissue; immunocytochemistry; in situ hybridization; laboratory mouse; neuritic plaques; neuropathology; postmortem; presenilin; protein localization; protein metabolism; protein protein interaction; protein transport

The neuronal adaptor protein X11alpha/mint-1 interacts with amyloid precursor protein (APP) to regulate its trafficking and processing in vitro. In transfected non-neuronal cells, X11alpha inhibits alpha- and gamma- but not beta- cleavage of APP. Because the phosphotyrosine binding (PTB) domain of X11alpha interacts specifically with the APP family, X11alpha appears to inhibit gamma-cleavage of APP specifically while sparing gamma-cleavage of Notch and other substrates of regulated intramembranous proteolysis. To determine the in vivo significance of these in vitro data, we will generate and characterize novel hX11alpha transgenic mice and X11alpha knockout mice and examine murine APP metabolism. Crosses of these mice to Tg2576 mice (transgenic for the Swedish mutation of hAPP, or hAPPswe) will probe the effects of XI la on hAPPswe metabolism and on the development of partial AD-like phenotypes in aging brain. A recent human genome-wide analysis revealed significant linkage of sporadic AD to single nucleotide polymorphisms (SNPs) on chromosome 9, perhaps including the X11alpha region. We will probe genetic linkage of SNPs in the X11alpha region to sporadic AD by using genomic DNA extracted from samples from AD subjects versus carefully-matched control subjects. The specific aims are to: 1) generate X11alpha knockout and hX11alpha transgenic mice and determine effects on murine APP metabolism in brain and in primary neuronal cultures, 2) cross X11alpha knockout and hX11alpha transgenic mice with Tg2576 mice to determine a) modulatory effects on hAPPswe metabolism in brain and in neuronal cultures, and b) development of AD-like phenotypes with aging, and 3) elucidate the SNPs and haplotypes within or adjacent to the X11alpha gene of AD cases and age-, gender-, and ApoE-matched controls to determine if there is a statistically significant link to sporadic AD. Specific aim 3 will study DNA samples obtained from the Pathology Core and from other ADRCs. These results will 1) inform the normal functions of X11alpha as well as APP and its derivatives in CNS neurons, 2) lay the groundwork for viral-vector based gene therapy of AD using either X11alpha or its PTB domain in hAPP transgenic mouse models, and 3) probe a potential genetic risk factor of sporadic AD.

神经元衔接蛋白 X11alpha/mint-1 与淀粉样前体蛋白 (APP) 相互作用，调节其体外运输和加工。在转染的非神经元细胞中，X11alpha 抑制 APP 的 α 和 γ 裂解，但不抑制 β 裂解。由于 X11alpha 的磷酸酪氨酸结合 (PTB) 结构域与 APP 家族特异性相互作用，因此 X11alpha 似乎特异性抑制 APP 的 γ 裂解，同时保留 Notch 和其他受调节膜内蛋白水解底物的 γ 裂解。为了确定这些体外数据的体内意义，我们将生成并表征新型 hX11alpha 转基因小鼠和 X11alpha 敲除小鼠，并检查小鼠 APP 代谢。这些小鼠与Tg2576小鼠（针对hAPP或hAPPswe的瑞典突变的转基因）的杂交将探究XIla对hAPPswe代谢以及对老化大脑中部分AD样表型的发展的影响。最近的一项人类全基因组分析揭示了散发性 AD 与 9 号染色体上的单核苷酸多态性 (SNP) 之间的显着关联，其中可能包括 X11α 区域。 我们将通过使用从 AD 受试者与仔细匹配的对照受试者样本中提取的基因组 DNA 来探究 X11α 区域中的 SNP 与散发性 AD 的遗传关联。具体目标是：1) 产生 X11alpha 敲除和 hX11alpha 转基因小鼠，并确定对大脑和原代神经元培养物中小鼠 APP 代谢的影响，2) 将 X11alpha 敲除和 hX11alpha 转基因小鼠与 Tg2576 小鼠杂交，以确定 a) 对 hAPPswe 的调节作用b) 大脑和神经元培养物中的新陈代谢，以及 b) 随着衰老而出现 AD 样表型，以及 3) 阐明AD 病例和年龄、性别和 ApoE 匹配对照的 X11alpha 基因内或邻近的 SNP 和单倍型，以确定与散发性 AD 是否存在统计学上显着的联系。具体目标 3 将研究从病理学核心和其他 ADRC 获得的 DNA 样本。这些结果将 1) 告知正常功能 X11alpha 以及 APP 及其衍生物在 CNS 神经元中的作用，2) 为在 hAPP 转基因小鼠模型中使用 X11alpha 或其 PTB 结构域进行基于病毒载体的 AD 基因治疗奠定了基础，以及 3) 探讨了潜在的遗传风险因素零星的AD。