Evolving New Glycosaminoglycan Mimetics

项目摘要 糖胺聚糖（Glycosaminoglycans，GAG）在许多生理和病理过程中起着重要作用 例如细胞分裂、炎症、神经发育和癌症转移。长 GAG的多糖链含有各种硫酸化二糖， 富含硫酸盐和硫酸化不足的区域。这种丰富的结构多样性使GAG， 硫酸乙酰肝素（HS）与许多蛋白质相互作用并调节关键信号通路。 然而，努力了解它们的结构-功能关系并利用其 治疗潜力受到GAG化学复杂性和缺乏 工具.目前，还没有工具来操纵GAG与特定蛋白质的相互作用 因此，确定它们的确切作用的努力变得复杂。该项目的目标是 开发用于选择性调节GAG活性的新型化学探针。我们将使用定向 基于进化的方法来创建一类新的GAG模拟物-多价糖肽 附加短而活跃的HS基序-以调节特定的HS-蛋白质相互作用。随机 通过定向进化对肽序列进行取样应该允许选择结构 包含HS基序的理想数量和排列。除了最佳HS聚类之外， 所选的肽应该含有被目的蛋白识别的肽基序， 产生高度特异性的GAG探针。在目标1中，我们将与克劳斯合作， 实验室开发的方法，并产生HS模拟物，选择性地相互作用， 成纤维细胞生长因子2（FGF 2），一种参与细胞迁移，血管生成， 和差异化。在目标2中，我们将进化出与特定形式的tau蛋白结合的糖肽， 微管相关蛋白与痴呆症如阿尔茨海默病和 帕金森氏症。我们将使用这些HS模拟物来了解潜在的机制 tau摄取进入神经元和神经变性。此外，我们将探讨我们的 模拟物可以阻断tau的细胞间扩散及其致病后果。在目标3中， 我们将进化出结合趋化因子（特别是CXCL 9、CXCL 10和CXCL 11）的糖肽， 一类治疗上重要的蛋白质，是炎症的关键介质。我们的探针 应该为趋化因子的自相矛盾的功能冗余提供独特的见解， 使我们能够区分它们各自的角色。这些研究将共同产生一部小说 一类基于GAG的探针，用于了解GAG的生理功能，并且可以 最终导致新的治疗线索或方法的疾病，如癌症， 神经变性疾病、炎性和自身免疫性疾病以及感染性疾病。

Project Summary Glycosaminoglycans (GAGs) play important roles in many physiological and pathological events such as cell division, inflammation, neural development, and cancer metastasis. The long polysaccharide chains of GAGs contain various sulfated disaccharides that are organized into sulfate-rich and under-sulfated domains. This rich structural diversity enables GAGs such as heparan sulfate (HS) to interact with numerous proteins and regulate key signaling pathways. However, efforts to understand their structure-function relationships and harness their therapeutic potential have been hampered by the chemical complexity of GAGs and a lack of tools. At present, there are no tools to manipulate the interactions of GAGs with specific proteins of interest, thus complicating efforts to pinpoint their precise roles. The goal of this project is to develop novel chemical probes for selectively modulating GAG activity. We will use a directed evolution-based approach to create a new class of GAG mimetics – multivalent glycopeptides appended with short, active HS motifs – to modulate specific HS-protein interactions. Random sampling of peptide sequences by directed evolution should allow for the selection of structures containing the ideal number and arrangement of HS motifs. In addition to optimal HS clustering, selected peptides should contain peptide motifs recognized by the protein of interest, thus generating highly specific GAG probes. In Aim 1, we will work in collaboration with the Krauss laboratory to develop the approach and generate HS mimetics that interact selectively with fibroblast growth factor 2 (FGF2), a key growth factor involved in cell migration, angiogenesis, and differentiation. In Aim 2, we will evolve glycopeptides that bind to specific forms of tau, a microtubule-associated protein linked to dementias such as Alzheimer's disease and Parkinson's disease. We will use these HS mimetics to understand the mechanisms underlying tau uptake into neurons and neurodegeneration. In addition, we will explore whether our mimetics can block the intercellular spreading of tau and its pathogenic consequences. In Aim 3, we will evolve glycopeptides that bind chemokines (specifically CXCL9, CXCL10 and CXCL11), a class of therapeutically important proteins that are key mediators of inflammation. Our probes should provide unique insights into the paradoxical functional redundancy of chemokines, enabling us to tease apart their individual roles. Together, these studies will produce a novel class of GAG-based probes for understanding the physiological functions of GAGs and may ultimately lead to new therapeutic leads or approaches to diseases such as cancer, neurodegenerative diseases, inflammatory and autoimmune disorders, and infectious diseases.