Targeting Apolipoprotein E4-related Neuropathology

描述(由申请人提供)： 阿尔茨海默病(AD)是发达国家增长最快的疾病之一。已有400万美国人被诊断出患有这种疾病，随着人口老龄化和预期寿命的增加，这种疾病的患病率预计将在未来20年内翻一番。然而，目前还没有真正有效的治疗方法来预防甚至延缓AD的发展。载脂蛋白(Apo)E4的存在是AD发病的主要危险因素或易感基因。载脂蛋白E4显然是为了增加散发性和家族性迟发性AD的发生和降低发病年龄而建立的。在不同的人群研究中，AD患者携带至少一个apoE4等位基因的数量从50%到80%不等(apoE4等位基因出现在大约15%的普通人群中)。对apoE结构和功能的研究表明，apoE4具有结构域相互作用的独特构象，即氨基末端的精氨酸61和羧基末端的谷氨酸255相互作用。APOE3是最常见的载脂蛋白E亚型，不能与结构域相互作用，具有更开放的构象。ApoE4的许多区别于apoE3的功能特性似乎受到结构域相互作用的调节。因此，支持这一建议的假设是，如果我们能够阻止apoE4假定其有害的结构构象，我们可能会阻止apoE4相关的神经病理。我们将使用荧光共振能量转移(FRET)(特定目标1)来识别能够阻止apoE4中结构域相互作用的小分子。结合FRET实验筛选化学文库将鉴定在结构和功能上将apoE4转化为“apoE3 1ike”分子的化合物。此外，我们将使用荧光释放分析来识别能够防止富含磷脂的膜的apoE4失稳的小分子(特定目标2)。载脂蛋白E4细胞内膜的不稳定是载脂蛋白E4与神经病理相关的一种机制。在化学文库筛选中使用这些分析方法将增加我们识别小分子(“HITS”)的机会，这些小分子通过不同的机制调节apoE4构象和相关的神经病理。最终，我们的目标将是“击中”先导化合物，这些化合物可能会产生一种预防或延缓载脂蛋白E4相关神经病理的药物。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is one of the most rapidly growing disorders in developed countries. Four million Americans have been diagnosed with this disorder, and as the population grows older and life expectancy increases, the prevalence is expected to double in the next 20 years. Yet at the present time there are no truly effective therapeutics to prevent or even retard the development of AD. The risk factor or susceptibility gene proven to play a major role in AD pathogenesis is the presence of apolipoprotein (apo) E4. ApoE4 is clearly established to increase the occurrence and lower the age of onset of the sporadic and familial forms of late-onset AD. The number of AD patients carrying at least one apoE4 allele ranges from 50-80% in different population studies (the apoE4 allele occurs in approximately 15% of the general population). Studies of the structure and function of apoE have revealed that apoE4 possesses a unique conformation characterized by domain interaction, i.e., arginine 61 in the amino terminus and glutamic acid 255 in the carboxyl terminus interact. ApoE3, the most common apoE isoform, is incapable of domain interaction and has a more open conformation. Many functional properties of apoE4 that distinguish it from apoE3 appear to be modulated by domain interaction. Thus, the hypothesis driving this proposal is that if we could prevent apoE4 from assuming its detrimental structural conformation, we might block the apoE4-related neuropathology. We will use fluorescence resonance energy transfer (FRET) (Specific Aim 1) to identify small molecules capable of preventing domain interaction in apoE4. Screening of chemical libraries in combination with the FRET assay will identify compounds that convert apoE4 to an "apoE3 1ike" molecule structurally and functionally. In addition we will use a fluorescence-release assay to identify small molecules capable of preventing apoE4 destabilization of phospholipid-rich membranes (Specific Aim 2). ApoE4 destabilization of intracellular membranes represents one mechanism whereby apoE4 could be related to neuropathology. Use of these assays in chemical library screening will increase our chances of identifying small molecules ("hits") that act through different mechanisms to modulate apoE4 conformation and related neuropathology. Ultimately, it will be our goal to take "hits" to lead compounds that may give rise to a drug that prevents or retards apoE4-related neuropathology.