Identify Abeta Oligomer Inhibitors By Combinatorial Chemistry

描述(申请人提供)：阿尔茨海默病(AD)是痴呆症的主要原因，也是全世界最令人残疾和负担最大的健康状况之一。目前，AD急需开发新的化合物。最近的研究支持，由淀粉样β蛋白(Ab)组成的神经毒性寡聚体的聚集是AD发病机制中的一个中心事件。最近，中和抗体低聚物(Abo)的神经毒性作用的小分子化合物在几项研究中显示出了希望。我们采用了一种新的方法，利用组合化学和高通量筛选方法来发现细胞渗透性的、ABO结合的小分子配体，这些小分子配体可以在细胞外和神经元内阻断ABO毒性。我们假设这些Abo配体将与Abo相互作用，以掩盖其与细胞靶标相互作用的表位，防止或逆转抗体的聚集，并降低Abo的水平。这些效应将在AD小鼠模型中提供神经保护，防止AD样异常。为此，我们从几个组合文库中筛选出一种有希望的化合物，命名为LRL22。在这一方案中，我们计划使用一珠一化合物(OBOC)组合库方法(目标1)进一步优化LRL22。使用这种方法，可以很容易地同时产生和筛选数千到数百万种化合物。我们将基于LRL22的构建块合成OBOC文库，并通过超高通量的微珠结合实验筛选与ABO结合的化合物。选定的ABO配体将使用我们的高通量基于细胞的ABO毒性分析进一步筛选其细胞保护作用。在目标2中，我们将确定所选择的ABO配体的结合动力学，并将确定结合是否导致干扰ABO与突触的相互作用，或逆转抗体聚集。两者都是理想的神经保护特性。在目标3中，我们将测试最有希望的化合物的体内疗效。我们将确定这种化合物的应用是否减少了名为3xTg-AD小鼠模型中早期神经元内抗体沉积的水平。优化后的化合物有望成为治疗阿尔茨海默病的药物。由于我们选择的化合物的一个重要性质是与抗体聚集体结合，它们也可能开发成淀粉样蛋白显像剂。与公共健康相关：淀粉样β蛋白对脑细胞有毒，被广泛认为是治疗阿尔茨海默病的药物靶点。我们将使用新兴的化学和细胞生物学技术来寻找能够阻断淀粉样β蛋白毒性作用的小分子化合物。这些化合物可被开发成阿尔茨海默病的治疗剂，或用于阿尔茨海默病的放射诊断的显像剂，阿尔茨海默病是全球痴呆症的主要原因。

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) is the major cause of dementia and one of the most disabling and burdensome health conditions worldwide. Currently there is an urgent need for new compound development for AD. Recent studies support that the accumulation of neurotoxic oligomeric aggregates made of the amyloid-beta protein (Ab) is a central event in the pathogenesis of AD. Recently, small molecule compounds that neutralize the neurotoxic effect of Ab oligomers (AbO) have shown promises in several studies. We have taken a new approach employing combinatorial chemistry and high throughput screening methods to discover cell-permeable, AbO-binding small molecule ligands that block AbO toxicity within both extracellular and intraneuronal sites. We hypothesize that these AbO ligands would interact with AbO to mask their epitopes that interact with cell targets, to prevent or reverse the aggregation of Ab peptides, and to reduce the level of AbO. These effects would provide neuroprotection from AD-like abnormalities in AD mouse models. Toward these ends, we have identified from screening several combinatorial libraries a promising compounds named LRL22. In this proposal, we plan to further optimize LRL22 using the "one-bead one-compound (OBOC)" combinatorial library method (Aim 1). Using this method, thousands to millions of compounds can be easily generated and screened concurrently. We will synthesize OBOC libraries based on the building blocks of LRL22 and select compounds that bind AbO by screening using the ultra high throughput on-bead binding assay. The selected AbO ligands will be further screened for their cell protective effect using our high throughput cell-based AbO toxicity assays. In Aim 2, we will determine the binding kinetics of selected AbO ligands, and will determine whether the binding results in interference with the AbO's interaction with synapses, or the reversal of Ab aggregation. Both are desirable neuroprotective properties. In Aim 3, we will test the in vivo efficacy of the most promising compound. We will determine whether the application of this compound reduces the levels of early intraneuronal Ab deposits in an AD mouse model called 3xTg-AD mice. Optimized compounds might be developed into therapeutic agents for AD. Since an important property of our selected compounds is binding to Ab aggregates, they might also be developed into amyloid imaging agents too. PUBLIC HEALTH RELEVANCE: The amyloid-beta protein is toxic to brain cells and is widely considered a drug target for Alzheimer's disease treatment. We will use emerging chemical and cell biological technologies to find small molecular compounds that block the toxic effect of the amyloid-beta protein. These compounds can be developed into therapeutic agents for Alzheimer's disease or into imaging agents for radiological diagnosis of Alzheimer's disease, a leading cause of dementia worldwide.