A PSGL-1 Glycopeptide Mimetic for Treatment of Venous Thromboembolism

 描述(申请人提供)：我们目前缺乏降低深静脉血栓形成风险而不伴随出血风险或显著改变血栓后综合征发展的治疗方法。在这项建议中，我们假设P-选择素糖蛋白配体-1是P-、L-和E-选择素的配体，为设计一系列新的拟糖类似物提供了一个起点，这些类似物将抑制静脉血栓形成，促进血栓溶解，并限制晚期组织重塑事件。在这方面，我们已经确定GSnP-6作为一个稳定的、高亲和力的PSGL-1模拟物，为设计一系列高效的选择素特异性拮抗剂提供了一个独特的结构支架。具体来说，我们打算：(1)确定GSnP-6在小鼠静脉血栓形成模型中的效力。在我们研究的第一阶段，我们将定义 GSnP-6，以及GSnP-6的聚乙二醇偶联物。提供最佳给药方案的给药方案将被选择用于后续的体内研究。在这些研究的第二阶段，将使用急性和慢性静脉血栓形成的闭塞和非闭塞小鼠模型来确定GSnP-6的疗效。这些研究将使我们能够确定GSnP-6的能力，以防止静脉血栓的启动和传播，促进血栓消退，并限制晚期组织重塑事件。(2)设计新的结构更简单、具有高选择素结合亲和力的PSGL-1糖链模拟物。初步的分子动力学模拟表明，并不是所有天然PSGL-1配体或GSnP-6中的单糖都直接与结合亲和力有关。这一观察结果提供了一个机会，通过用更简单的结构类似物取代非关键残基来极大地简化化学合成。将对GSnP-6到P-选择素的一系列拟议简化结构变体的自由和结合形式进行MD模拟。结构变体， 显示与P-选择素的最大负总相互作用能，这预示着一种HIH亲和选择素抑制剂，将被选择用于合成，以及在体外和体内的表征。具有最大效力的类似物将被选择用于闭塞和非闭塞的静脉血栓形成小鼠模型的进一步研究。(3)观察GSnP-6及其类似物对小鼠癌性静脉血栓形成的影响。恶性肿瘤是静脉血栓栓塞症的主要危险因素，尽管抗凝效果最佳，但在这类患者中，血栓复发和出血并发症的风险显著增加。在这些研究的第一阶段，将在荷瘤小鼠身上评估GSnP-6在预防和治疗静脉血栓形成方面的疗效。在第二阶段，将评估在AIM 2中确定的有前景的结构简化的选择素拮抗剂，以评估它们抑制静脉血栓形成和限制荷瘤小鼠血栓后综合征的发展的能力。

 DESCRIPTION (provided by applicant): We currently lack therapies that reduce the risk of deep vein thrombosis without an attendant risk of bleeding or that significantly alter the development of postthrombotic syndrome. In this proposal, we postulate that P-selectin glycoprotein ligand-1 (PSGL-1), which is a ligand for P-, L-, and E-selectin provides a starting for the design of a new series of glycomimetic analogs that will suppress venous thrombosis, promote thrombus resolution, and limit late tissue remodeling events. In this regard, we have determined that GSnP-6, as a stable, high-affinity PSGL-1 mimetic, affords a unique structural scaffold for the design of a broad range of highly potent selectin-specific antagonists. Specifically, we intend to: (1) Define the potency of GSnP-6 in murine models of venous thrombosis. In the first phase of our investigations, we will define the pharmacokinetic profile of GSnP-6, as well as poly (ethylene glycol) (PEG) conjugates of GSnP-6. The dosing regimen affording the best drug delivery profile will be selected for subsequent in vivo studies. In the second phase of these investigations, the efficacy of GSnP-6 will be defined using occlusive and non-occlusive murine models of acute and chronic venous thrombosis. These studies will allow us to define the capacity of GSnP-6 to prevent the initiation and propagation of venous thrombosis, promote thrombus resolution, and limit late tissue remodeling events. (2) Design new structurally simpler PSGL-1 glycomimetics that display high selectin binding affinity. Preliminary molecular dynamics simulations have indicated that not all of the monosaccharides in the native PSGL-1 ligand or GSnP-6 contribute directly to binding affinity. This observation provides an opportunity to greatly simplify chemical synthesis by replacing non-critical residues with simpler structural analogs. MD simulations will be performed for free and bound forms of a series of proposed simplified structural variants of GSnP-6 to P-selectin. Structural variants that display the largest negative total interaction energy with P- selectin, which is predictive of a hih affinity selectin inhibitor, will be selected for synthesis, as well as characterization in vitro ad in vivo. The analog with the greatest potency will be selected for further investigation in occlusive and non-occlusive murine models of venous thrombosis. (3) Determine the effectiveness of GSnP-6 and related analogs in murine models of cancer associated venous thrombosis. Malignancy is a major risk factor for venous thromboembolism and despite optimal anticoagulation the risk of recurrent thrombosis and bleeding complications is substantially increased in this patient population. In the first phase of these investigations, the efficacy of GSnP-6 in the prevention and treatment of venous thrombosis will be assessed in tumor bearing mice. In the second phase, promising structurally simplified selectin antagonists that have been identified in Aim 2 will be assessed for their capacity to inhibit venous thrombosis and limit the development of postthrombotic syndrome in tumor bearing mice.