ROLE OF APP-RELATED PROTEINS DURING NEURONAL MIGRATION

APP 相关蛋白在神经元迁移过程中的作用

• 批准号: 7476496
• 负责人: PHILIP F COPENHAVER
• 金额: $ 27.04万
• 依托单位: OREGON HEALTH & SCIENCE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7476496
• 关键词: Address; Affect; Alkaline Phosphatase; Alzheimer' s Disease; Amyloid beta-Protein; Amyloid beta-Protein Precursor; Antibodies; Behavior; Biological; Biological Assay; Biological Models; Brain; Cells; Chimeric Proteins; Cues; Cytoplasmic Tail; Development; Disruption; Down-Regulation; Embryo; Embryonic Nervous System; Endocrine; Enteric Nervous System; Epitopes; Event; Family member; Foundations; Future; G-Protein-Coupled Receptors; Generations; Go Alpha Subunit; Goals; Heterotrimeric GTP-Binding Proteins; Homologous Gene; Human; Human Development; Immigration; In Vitro; Indium; Invertebrates; Investigation; Label; Ligands; Manduca sexta; Mediating; Molecular; Moths; Nature; Nervous system structure; Neurons; Pathology; Pathway interactions; Pattern; Physiological; Play; Preparation; Process; Protein Binding; Protein Family; Protein Fragment; Protein Inhibition; Protein Isoforms; Proteins; Regulation; Relative (related person); Research; Role; Role playing therapy; Senile Plaques; Signal Pathway; Signal Transduction; Signaling Molecule; System; Testing; Thinking; Visceral; age related neurodegeneration; amyloid precursor protein processing; cell motility; expression cloning; gene cloning; in vivo; insight; intracellular protein transport; migration; migratory population; neuronal guidance; neurotoxic; novel; protein function; protein transport; receptor; receptor coupling; research study; response; secretase; synaptogenesis; tool; trafficking

DESCRIPTION (provided by applicant): The long-term goals of this proposal are to determine the in vivo functions of proteins related to the amyloid precursor protein (APP) during normal development, and to gain insight into how perturbations of these functions may contribute to the pathology of Alzheimer's Disease (AD). AD is associated with the misregulated processing of APP by a combination of secretases, which results in the generation of excessive beta-amyloid fragments (Abeta) that can aggregate into amyloid plaques within the nervous system. Although Abeta has been shown to have neurotoxic effects, the normal functions of APP may also be disrupted by this process, contributing to the pathology of AD. A variety of studies in vitro have indicated that APP can act as a transmembrane receptor capable of regulating neuronal migration and outgrowth via several candidate intracellular signaling pathways. Particularly compelling are experiments showing that APP695 (considered a neuronal form of APP) binds directly to the heterotrimeric G protein Go-alpha and can regulate its activity. However, a functional analysis of this interaction has been precluded by complexities associated with the mammalian nervous system, and due to the lack of a biologically relevant assay for APP-Go-alpha signaling. To address this issue, a model system (the enteric nervous system or ENS of Manduca sexta) has been established, in which an identified set of migratory neurons (the EP cells) can be visualized and manipulated within the intact nervous system. The EP cells express an orthologue of APP (msAPPL, or APP-Like protein), which undergoes regulated trafficking and processing as the neurons develop. MsAPPL also interacts with Goa in their leading processes. Preliminary studies have shown that inhibiting msAPPL expression in the EP cells induces ectopic, inappropriate migration, consistent with a disruption of Go-alpha- mediated signaling events. The goals of this proposal are to test the hypothesis that msAPPL acts as a novel Go-alpha-coupled receptor: when activated by endogenous ligands the ENS, it regulates neuronal guidance in a Go-alpha-dependent manner. The nature of msAPPL-Go-alpha interactions in the migrating neurons and the role that secretases may play in modulating msAPPL-dependent aspects of migration will also be explored. Lastly, an expression cloning strategy will be employed to identify candidate ligands for msAPPL, using the ENS as an in vivo assay system. These studies will provide new insight into the molecular mechanisms of APP-related signaling in the developing nervous system, and they should serve as a foundation for future research into how disrupting the normal functions of APP may contribute to the pathology of AD.

描述(申请人提供)：这项建议的长期目标是确定与淀粉样前体蛋白(APP)相关的蛋白质在正常发育过程中的体内功能，并深入了解这些功能的扰动可能如何导致阿尔茨海默病(AD)的病理。AD与一系列分泌酶对APP的错误处理有关，这会导致过量的β-淀粉样蛋白片段(Abeta)的产生，这些片段可以聚集成神经系统内的淀粉样斑块。虽然Abeta已被证明具有神经毒性作用，但APP的正常功能也可能被这一过程扰乱，从而导致AD的病理变化。许多体外研究表明，APP可以作为跨膜受体，通过几条候选的细胞内信号通路来调节神经元的迁移和生长。尤其引人注目的是实验表明，APP695(被认为是APP的一种神经元形式)直接与异源三聚体G蛋白GO-α结合，并可以调节其活性。然而，由于哺乳动物神经系统的复杂性，以及缺乏对APP-GO-α信号的生物学相关分析，这种相互作用的功能分析一直是不可能的。为了解决这个问题，已经建立了一个模型系统(Manduca sexta的肠道神经系统或ENS)，在这个系统中，可以在完整的神经系统内可视化和操纵一组已识别的迁移神经元(EP细胞)。EP细胞表达APP(msAPPL，或APP样蛋白)的同源蛋白，随着神经元的发育，APP经历受调控的运输和处理。MsAPPL还在其领导进程中与GOA进行互动。初步研究表明，抑制EP细胞中msAPPL的表达会诱导异位的、不适当的迁移，这与GO-α介导的信号事件的中断是一致的。这一提议的目的是验证msAPPL作为一种新的GO-α偶联受体的假设：当被内源性配体激活时，它以GO-α依赖的方式调节神经元的引导。此外，还将探讨迁移神经元中msAPPL-GO-α相互作用的性质，以及分泌酶在调节依赖于msAPPL的迁移方面可能发挥的作用。最后，将采用表达克隆策略，使用ENS作为体内检测系统来确定msAPPL的候选配体。这些研究将为APP相关信号在神经系统发育中的分子机制提供新的见解，并为未来研究APP的正常功能如何导致AD的病理奠定基础。