Expedited Synthesis of Glycosaminoglycans Containing Defined Sulfation Domains

 描述（由申请人提供）：硫酸乙酰肝素（HS）和硫酸软骨素（CS）糖胺聚糖在许多生理和病理事件中发挥重要作用，如细胞分裂、炎症、神经元发育和癌症转移。自然存在的HS和CS显示出各种各样的硫酸化模式。虽然这种结构多样性赋予HS和CS与许多蛋白质相互作用的能力，但它极大地阻碍了破译其结构-功能关系的能力。为了极大地推进对糖胺聚糖的生物学功能的理解，至关重要的是访问具有明确定义的硫酸化序列的HS和CS寡糖的大型结构多样的文库。迄今为止，HS和CS的合成方法大多是以目标为导向的，仅产生少量寡糖。此外，仍然难以制备比十二糖长的HS和CS序列。为了应对这些挑战，在HS和CS合成和生物学方面具有强大互补专业知识的三个研究小组联合起来，以实现以下目标。在目标1中，提出了新的合成策略来加速HS寡糖的合成。将开发方法来制备代表所有可能的2-O，6-O和N硫酸化基序的256个HS四糖的第一个综合文库，以及结构多样的3-O硫酸化四糖和HS六糖的文库。在目标2中，我们提出了新的有效的，具有成本效益的途径来访问第一个全面的库CS四糖轴承所有可能的哺乳动物硫酸化序列。在目标3中，将制备基于HS/CS寡糖的聚合物和头-尾多聚体，以能够获得含有尺寸接近天然多糖的均匀硫酸化聚糖的结构。这些模拟物将具有在天然存在的CS和HS多糖中发现的类似结构域结构和多价性质。在目标4中，我们将验证我们的分子可以使用完善的测定法概括HS和CS多糖的生物学功能的假设，包括抗凝、神经元生长和蛋白结合测定法。此外，我们将探索这些分子选择性靶向临床上重要的蛋白质家族成纤维细胞生长因子的潜力。总之，该项目将提供更快，更实惠的HS和CS合成，大大扩展目前通过合成可获得的“化学空间”，使HS和CS之间的第一次直接，深入的比较成为可能，并提供新的试剂来控制这些生物医学重要分子的活性。

 DESCRIPTION (provided by applicant): Heparan sulfate (HS) and chondroitin sulfate (CS) glycosaminoglycans play important roles in many physiological and pathological events, such as cell division, inflammation, neuronal development, and cancer metastasis. Naturally existing HS and CS display a diverse range of sulfation patterns. While this structural diversity bestows HS and CS with the ability to interact with many proteins, it greatly hinders the ability to decipher their structure-function relationships. In order to dramatically advance an understanding of the biological functions of glycosaminoglycans, it is critical to access large, structurally diverse libraries of HS and CS oligosaccharides bearing well-defined sulfation sequences. To date, synthetic methodologies toward HS and CS are mostly target oriented, resulting in only small sets of oligosaccharides. Furthermore, it remains difficult to prepare HS and CS sequences longer than a dodecasaccharide. To address these challenges, three research groups with strong, complementary expertise in HS and CS synthesis and biology have joined forces to accomplish the following aims. In Aim 1, new synthetic strategies are proposed to accelerate the synthesis of HS oligosaccharides. Methodologies will be developed to prepare the first comprehensive library of 256 HS tetrasaccharides representing all of the possible 2-O, 6-O and N sulfation motifs, along with a library of structurally diverse 3-O sulfated tetrasaccharides and HS hexasaccharides. In Aim 2, we propose new efficient, cost-effective routes to access the first comprehensive library of CS tetrasaccharides bearing all of the possible mammalian sulfation sequences. In Aim 3, HS/CS oligosaccharide-based polymers and head-to-tail multimers will be prepared to enable access to structures containing homogeneously sulfated glycans with sizes approaching natural polysaccharides. These mimetics will possess similar domain structures and multivalent properties found in naturally existing CS and HS polysaccharides. In Aim 4, we will validate the hypothesis that our molecules can recapitulate the biological functions of HS and CS polysaccharides using well-established assays, including anticoagulation, neuronal growth, and protein-binding assays. Furthermore, we will explore the potential for these molecules to selectively target a clinically important family of proteins, the fibroblast growth factors. Together, this project will provide faster, more affordable syntheses of HS and CS, greatly expand the "chemical space" currently accessible by synthesis, enable the first direct, in-depth comparisons between HS and CS, and provide novel agents to control the activities of these biomedically important molecules.