Probing the Proteinopathy Component of Light Chain Amyloidosis Pharmacologically

项目摘要 免疫球蛋白轻链淀粉样变性（AL）是一种由轻链淀粉样变性引起的变性疾病 (LC)错误折叠和聚集。全长（FL）LC由克隆扩增的浆细胞分泌 因此，AL患者患有浆细胞癌和LC错误折叠， 聚集相关蛋白质病，似乎损害器官功能，导致进行性 器官退化目前，AL是通过改变用途的多发性骨髓瘤药物来治疗的，这些药物可以杀死克隆血浆， 分泌FL LC的细胞。需要不同的机械治疗方法，特别是对患者 患有心脏病的患者不能耐受目前可用的化疗方案。在这一提议中， 我们寻求生产最终将使FL LC动力学稳定剂的临床试验成为可能的主要候选物 在具体目标1中，我们假设LC动力学稳定剂 在我们的命中，以铅药物化学的努力，可以被分解成四个亚结构， “锚子结构”、“芳族核”、“接头模块”和“末端芳族组分”。这 假设是基于迄今为止解决的11（FL LC）2·动力学稳定剂晶体结构以及结构- 在过去18年中合成了300多种FL LC 2动力学稳定剂， 个月我们将继续使用我们在开发药物时学到的基于结构的设计原则 除了计算工具，特别是薛定谔LiveDesign软件， 代谢不稳定且具有潜在毒性的香豆素芳香核和二乙基苯胺锚子结构 在我们的LC动力学稳定剂中，同时引入功能以减少白蛋白结合。LiveDesign软件 利用预测LogP值和对接评分的加权组合准确预测白蛋白 约束力在具体目标2中，我们将开发FL LC 2血浆结合选择性测定，以验证我们的 计算努力减少白蛋白结合。首先，我们将荧光标记的FL淀粉样蛋白 将LC与蛋白酶K和候选动力学稳定剂一起沿着加入合并的健康供体血浆中，并随后 蛋白酶K内切蛋白水解与FL LC 2随时间的色谱构象偏移相关。如果 动力学稳定剂候选物选择性地结合淀粉样蛋白生成FLLC 2超过所有其它血浆蛋白， 包括白蛋白，FL LC 2蛋白酶K的内蛋白水解将被阻止-该测定法得到了很大的发展。 接下来，将开发亚基交换测定以定量药物FL LC 2动力学稳定化， 人类血浆该试验还定量了与白蛋白结合的动力学稳定剂。荧光标记的 Cys 214 Ser FL LC 2变体促进提供动力学稳定剂KD的亚基交换实验 结合至添加至健康血浆中的FL LC 2变体，以及用于结合至健康血浆中的FL LC 2变体的动力学稳定剂KD。 血浆中的内源性人白蛋白。这些KD将用于产生结合选择性比率，即，KD为 动力学稳定剂与白蛋白结合/动力学稳定剂与FL LC 2结合的KD，我们将使其最大化。

Project Summary Immunoglobulin light chain amyloidosis (AL) is a degenerative disease that putatively arises from light chain (LC) misfolding and aggregation. Full-length (FL) LCs are secreted from a clonally expanded plasma cell population in AL. Thus, AL patients suffer from both a plasma cell cancer and a LC misfolding and aggregation-associated proteinopathy that appears to compromise organ function, leading to progressive organ deterioration. Currently, AL is treated by repurposed multiple myeloma drugs that kill the clonal plasma cells secreting FL LCs. Mechanistically distinct therapeutic approaches are needed, particularly for patients with cardiac involvement who cannot tolerate the currently available chemotherapy regimens. In this proposal, we seek to produce lead candidates that ultimately would enable a clinical trial on a FL LC kinetic stabilizer targeting the proteinopathy component of AL. In Specific Aim 1, we hypothesize that the LC kinetic stabilizers to be synthesized in our hit-to-lead medicinal chemistry efforts can be dissected into four substructures—the “anchor substructure”, the “aromatic core”, the “linker module” and the “terminal aromatic component”. This hypothesis is based on 11 (FL LC)2•kinetic stabilizer crystal structures solved to date as well as the structure- activity relationship data resulting from the synthesis of over 300 FL LC2 kinetic stabilizers during the past 18 months. We will continue to use structure-based design principles that we learned developing the drug tafamidis, in addition to computational tools, especially the Schrödinger LiveDesign software, to replace the metabolically unstable and potentially toxic coumarin aromatic core and the diethyl aniline anchor substructure in our LC kinetic stabilizers, while introducing functionality to reduce albumin binding. The LiveDesign software utilizes a weighted combination of the predicted LogP values and docking scores to accurately predict albumin binding. In Specific Aim 2, we will develop FL LC2 plasma binding selectivity assays to validate our computational efforts to diminish albumin binding. First, we will add fluorescently labeled FL amyloidogenic LCs to pooled healthy donor plasma, along with proteinase K and a candidate kinetic stabilizer, and follow proteinase K endoproteolysis linked to FL LC2 conformational excursions chromatographically over time. If the kinetic stabilizer candidate selectively binds the amyloidogenic FL LC2 over all the other plasma proteins, including albumin, FL LC2 proteinase K endoproteolysis will be prevented–this assay is largely developed. Next, a subunit exchange assay will be developed to quantify pharmacologic FL LC2 kinetic stabilization in human plasma. This assay also quantifies kinetic stabilizer binding to albumin. A fluorescently labeled Cys214Ser FL LC2 variant facilitates subunit exchange experiments that afford the KD of kinetic stabilizer binding to the FL LC2 variants added to healthy plasma, as well as the kinetic stabilizer KD for binding to endogenous human albumin in plasma. These KDs will be used to generate binding selectivity ratios, i.e., KD of kinetic stabilizer binding to albumin / KD of kinetic stabilizer binding to the FL LC2, which we will maximize.