ALZHEIMER'S AMYLOID PLAQUE PERSISTENCE IN VIVO

阿尔茨海默病（Alzheimer's disease，AD）是一种脑退行性疾病，临床上表现为记忆、认知、推理、判断和情绪稳定性的进行性丧失，逐渐导致严重的智力衰退并最终死亡。AD的特征在于含有β-淀粉样蛋白（Abeta）的不溶性纤维状淀粉样沉积物的脑积聚，其作为细胞外淀粉样斑块或在脑实质中的血管壁中。据信，脑中的A β淀粉样蛋白持续存在通过促进神经元损失和记忆功能障碍在AD发病机制中发挥中心作用。在过去的几年中，我们的研究已经确定，其他额外的因素，如特定的硫酸乙酰肝素蛋白聚糖（即串珠素），是必要的“纤维状”A β沉积在AD脑的形成和持久性。使用纯化的串珠素已经建立了一个一致的啮齿动物模型，用于脑中A β淀粉样蛋白的快速沉积和持久性。将Abeta +串珠蛋白聚糖输注到海马体中1或2周导致80/80只动物（100%）的嗜中性淀粉样蛋白沉积，相比之下，单独输注Abeta后70只动物中有41只（58.5%）。串珠素有助于A β淀粉样蛋白在脑中的长期持续和脑血管淀粉样蛋白沉积物的形成，在A β输注后未观察到。我们现在已经通过实施新的专有方案来显著推进这种动物模型，以诱导体外形成马耳他交叉嗜中性粒细胞淀粉样斑块样沉积物，其在形态学和超微结构上与来自AD脑的淀粉样斑块核心相似。新的动物建模方法可用于快速体内鉴定潜在的抗淀粉样蛋白斑块治疗剂，其靶向脑中的淀粉样蛋白斑块a）沉积，B）持久性和/或c）溶解和清除。该I期提案的主要目标是1）确定蛋白聚糖/GAG对淀粉样斑块形成的作用，和2）确定“淀粉样斑块”、“纤维状”Abeta持续存在和脑血管淀粉样蛋白沉积的解剖学和分子学后果。所述研究将进一步建立Abeta淀粉样蛋白斑块沉积和持久性的一致动物模型，并将允许（在II期提案中）快速筛选新的潜在治疗候选物以治疗AD中的Abeta斑块淀粉样变性。拟议的商业应用：阿尔茨海默病（AD）目前影响着400万至500万美国人，估计成本为800亿至1000亿美元。目前，没有治愈或有效的治疗方法，患者通常在发病后3-10年内死亡。迫切需要可以实施以快速测试抗A β淀粉样蛋白治疗剂的功效的新动物模型。我们已经发现了在试管中持续形成阿尔茨海默氏淀粉样斑块样沉积物的新方法，并正在建立体内淀粉样斑块持续存在的新动物模型。该模型可用于将来快速筛选新的抗淀粉样斑块治疗药物。

Alzheimer's disease (AD) is a degenerative brain disorder characterized clinically by progressive loss of memory, cognition, reasoning, judgement and emotional stability that gradually leads to profound mental deterioration and ultimately death. AD is characterized by the brain accumulation of insoluble fibrillar amyloid deposits containing the beta-amyloid protein (Abeta), either as extracellular amyloid plaques or in blood vessel walls in the brain parenchyma. Abeta amyloid persistence in brain is believed to play a central role in AD pathogenesis by contributing to neuronal loss and memory dysfunction. Over the last few years, our studies have determined that other additional factors, such as specific heparan sulfate proteoglycans (i.e. perlecan), are necessary for the formation and persistence of "fibrillar" Abeta deposits in AD brain. Use of purified perlecan has established a consistent rodent model for the rapid deposition, and persistence of Abeta amyloid in brain. 1 or 2- week infusions of Abeta + perlecan into hippocampus leads to congophilic amyloid deposits in 80 of 80 animals (100%), in comparison to 41 of 70 (58.5%) following infusions of Abeta alone. Perlecan contributes to the long- term persistence of Abeta amyloid in brain and the formation of cerebrovascular amyloid deposits, not observed following Abeta infusions. We have now significantly advanced this animal model by implementing new proprietary protocols to induce the in vitro formation of maltese-cross congophilic amyloid plaque-like deposits, which are morphologically and ultrastructurally similar to those amyloid plaque cores derived from AD brain. New animal modeling methodologies can be used for the rapid in vivo identification of potential anti-amyloid plaque therapeutics that target amyloid plaque a) deposition, b) persistence and/or c) dissolution and clearance, in brain. The major objectives of this phase I proposal are 1) to determine the role of proteoglycans/ GAGs on amyloid plaque formation, and 2) to determine anatomical and molecular consequences of "amyloid plaque", "fibrillar" Abeta persistence, and cerebrovascular amyloid deposition in brain. The studies described will further establish a consistent animal model for Abeta amyloid plaque deposition and persistence, and will allow (in a phase II proposal) for the rapid screening of new potential therapeutic candidates to treat Abeta plaque amyloidosis in AD. PROPOSED COMMERCIAL APPLICATIONS: Alzheimer's disease (AD) currently affects 4-5 million Americans, at an estimated costs of $80-$100 billion. Currently, there is no cure or effective treatment, and the patient usually dies within 3-10 years from disease onset. New animal models which can be implemented to rapidly test the efficacy of anti-Abeta amyloid therapeutics are desperately needed. We have discovered new methods to consistently form Alzheimer's amyloid plaque-like deposits in a test tube, and are establishing a new animal model of amyloid plaque persistence in vivo. This model can be utilized to rapidly screen for new anti- amyloid plaque therapeutics in the future.