NEURAL REGULATION AND PHYSIOLOGIC ACTIONS OF THE APP FAMILY OF PROTEINS

APP 蛋白质家族的神经调节和生理作用

• 批准号: 6234439
• 负责人: Walter J. Koroshetz
• 金额: $ 14.55万
• 依托单位: MASSACHUSETTS GENERAL HOSPITAL
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-04-15 至 1998-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6234439
• 关键词: G protein; RNase protection assay; aging; amyloid proteins; biological signal transduction; calcium channel; calcium flux; calcium indicator; divalent cations; gene expression; glutamate receptor; glutamates; immunoprecipitation; laboratory rat; neural transmission; neuroprotectants; neuroregulation; neutralizing antibody; protein biosynthesis; secretion; stress; synapses; tissue /cell culture; voltage /patch clamp; zinc

The nature of the genetic mutations associated with AD strongly suggest that an abnormality in the expression or processing of the amyloid precursor protein (APP) leads to AD pathology. How might aging itself, which underlies the vast majority of AD cases, lead to a similar pathology? Recent in vitro evidence establishes that secreted fragments of APP, APPS, improve neuronal CA ++ homeostasis and promote neuronal survival; secreted ABeta has opposite effects. A disruption of this balance, between the neurotoxic ABeta and the neuroprotective APPS, now seems a compelling mechanism which might contribute to AD pathology. Homologous proteins, the amyloid precursor-like proteins (APLPs), likely have functional and pathophysiologic roles in APP biology as well. Using electrophysiologic recording techniques, fluorescent Ca++ -indicator dyes and neurotoxicity assays, we have designed experiments to examine how APPs and APLPs and APLPs modulate important processes involved in Ca++ homeostasis including: voltage-dependent calcium channels, robust synaptic activity, glutamate-receptor activation and Ca++ release from internal stores. Since APPs, ABeta, and APLPs are secreted, present in synaptic terminals, modulate intraneuronal [Ca++], and are neuroprotective in excitotoxicity models, we suspect they play an important role in synaptic transmission. To test this, we plan to examine the effects of APPs and APLPs in a model system that exhibits easily controlled synaptic activity. Known mechanisms of APP regulation in non-neural tissues combined with newly found functional properties, strongly suggest that the synthesis and secretion of the APP family of proteins are regulated by inherently neural processes. In this proposal we plan to carefully examine the effects of neurotransmitter-receptor activation, thermal and metabolic neural stress, and activated second messenger systems on APP, APPs, ABeta and APLP synthesis and secretion. Our preliminary data indicate that a variety of physiologically important conditions differentially affect APP, APPs and APLP levels in neurons and glia and their overlying media. Aging-related disorders, like genetic mutations, could alter the functional activity, processing or synthesis of these molecules contributing to AD neurodegeneration. To study effects due to aging itself, we will compare regulatory and functional properties of the APP family of proteins in mature, month old cultures with cultures grown for greater than 6 months. Our goal is to discover how the functional properties and regulation of the various members of the APP family of molecules are coordinated in normal and stressed CNS tissue. Our central hypothesis is that a disorder in this relationship could adversely affect neuronal Ca++ homeostasis and thereby contribute to neurodegeneration in AD.

与AD相关的遗传突变的性质强烈表明 淀粉样蛋白的表达或处理异常 前体蛋白（APP）导致AD病理学。 会如何老化， 这是绝大多数AD案件的基础，导致类似 病理？ 最近的体外证据表明，分泌的碎片 应用程序，应用程序，改善神经元CA ++稳态并促进神经元 生存；分泌的Abeta具有相反的影响。 破坏这一点 现在的神经毒性Abeta和神经保护应用之间的平衡，现在 似乎是一种令人信服的机制，可能有助于AD病理学。 同源蛋白，淀粉样蛋白前体样蛋白（APLP），可能 在应用生物学中也具有功能性和病理生理作用。 使用 电生理记录技术，荧光Ca ++ - 调子染料 和神经毒性测定，我们设计了实验来研究 应用程序，APLP和APLPS调制CA ++涉及的重要过程 稳态包括：电压依赖性钙通道，稳健 突触活性，谷氨酸 - 受体激活和Ca ++从 内部商店。 由于应用程序，Abeta和APLP被分泌，因此 突触末端，调节神经内神经元[Ca ++]，为 兴奋性毒性模型中的神经保护作用，我们怀疑它们在玩 突触传播中的重要作用。 为了测试这一点，我们计划 在模型系统中检查应用程序和APLP的效果 易于控制的突触活动。 非神经组织中应用程序调节的已知机制结合 新发现的功能特性，强烈表明合成 蛋白质家族的分泌由固有地调节 神经过程。 在此提案中，我们计划仔细检查 神经递质激活，热和代谢的影响 神经压力和应用程序，应用程序，Abeta上激活的第二使者系统 以及APLP的合成和分泌。 我们的初步数据表明 生理上重要条件的种类差异影响 神经元和神经胶质的应用，应用程序和APLP级别及其上覆的媒体。 与衰老有关的疾病，例如基因突变，可能会改变 这些分子的功能活性，加工或合成 有助于AD神经退行性。 由于衰老而研究效果 本身，我们将比较应用程序的监管和功能属性 蛋白质家族在成熟的，一个月的文化中，有种植的文化 大于6个月。 我们的目标是发现该功能如何 应用程序家族的各个成员的财产和规定 分子在正常和应力的中枢神经系统组织中协调。 我们的中心 假设是，这种关系中的疾病可能会对 神经元CA ++稳态，从而有助于神经变性 广告。