Heteromutivalent Peptide-Lipid Nanoconstructs as Artificial Platelet Analogues

作为人工血小板类似物的异多价肽-脂质纳米结构

• 批准号: 10579965
• 负责人: Anirban Sen Gupta
• 金额: $ 53.27万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-02-08 至 2025-01-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10579965
• 关键词: Acute; Address; Adhesions; Alpha Granule; Alteplase; Attenuated; Award; Binding; Biocompatible Materials; Blood; Blood Coagulation Factor; Blood Platelets; Clinical; Coagulation Process; Collagen; Emergency Medicine; Encapsulated; Engineering; Enzymes; Exposure to; Fibrin; Fibrinogen; Generations; Goals; Hemorrhage; Hemostatic Agents; Hemostatic function; Hospitals; Hybrids; In Vitro; Injury; Integrins; Kinetics; Legal patent; Life; Lipids; Liposomes; Mediating; Military Personnel; Modeling; Morphology; Mus; N-formylmethionylphenylalanine; Patients; Peptides; Phosphatidylserines; Phospholipids; Plasma; Plasmin; Platelet Transfusion; Play; Polyphosphates; Research; Resources; Rodent; Role; Site; Stimulus; Surface; System; Tail; Technology; Testing; Thrombin; Transfusion; Trauma; Traumatic Hemorrhage; Vascular Endothelium; Whole Blood; analog; design; functional mimics; high risk; improved; in vivo; innovation; military trauma; mimetics; mimicry; mortality; nano; nanoparticle; peptidomimetics; portability; response; self assembly; trauma centers; von Willebrand Factor

Platelets play a central role in hemostasis via injury site-selective multi-step mechanisms of: (1) Adhesion to vWF and collagen, (2) Fibrinogen-mediated aggregation to form the primary hemostatic plug, (3) Biointerfacial presentation of anionic phosphatidylserine (PS) on the activated platelet surface for procoagulant amplification of thrombin (hence fibrin), and (4) clot-localized secretion of platelet granule contents (e.g. inorganic polyphosphate, PolyP) to locally enhance fibrin stability. These mechanisms are significantly compromised in non-compressible traumatic hemorrhage, which remains a major cause of mortality. The `gold standard' for treating such hemorrhage is massive transfusion of whole blood or components (platelets, plasma, RBC). Especially, platelet transfusion has shown tremendous clinical benefit in saving lives in trauma. However, platelets are rarely available in resource-limited hospitals and unavailable pre-hospital, due to challenges of storage, portability, high risk of bacterial contamination and very short shelf-life (~5 days). We aim at addressing this challenge by designing biomaterials-based `artificial platelet' nanoconstructs. To this end, utilizing a previous R01 award (HL121212) we developed self-assembled lipid-peptide nanoconstructs that mimic and integrate the platelet mechanisms of (1) and (2) stated above. This design showed hemostatic ability in vitro and in thrombocytopenic mouse tail-bleeding models, and modest efficacy in severe trauma models. Building on this, we now propose to mimic the mechanisms of (3) and (4) on a liposomal template by designing unique enzyme- responsive lipopeptides, that will subsequently allow integration of all four mechanisms onto a single nanoconstruct for a superior artificial platelet design. Our central hypothesis is `Modular amplification of hemostasis via mimicry of platelet's biointerfacial and secretory mechanisms within an artificial platelet construct can significantly attenuate hemorrhage and enhance survival in trauma'. To test this, our Specific Aims are to: (1) Evaluate stimuli (plasmin)-triggered exposure of PS on lipidic nanoconstructs for platelet-inspired amplification of thrombin (hence fibrin) site-specifically in trauma; (2) Evaluate stimuli (thrombin)-triggered release of inorganic polyphosphate (PolyP) as a payload from lipidic nanoconstructs for injury site-targeted stabilization of fibrin clot; and (3) Integrate these independent synergistic components in artificial platelet nanoconstructs to evaluate hemostatic efficacy and survival in rodent trauma model. The traumatic insult to vascular endothelium results in enhanced secretion of tissue plasminogen activator (hence plasmin) at the clot site, resulting in rapid fibrin degradation (hyperfibrinolysis) and compromising clot stability. Exploiting this plasmin to expose PS on `artificial platelet' surface will allow enhanced thrombin (and hence fibrin) generation to offset hyperfibrinolysis. This thrombin can then also act as a local trigger to destabilize the `artificial platelet' constructs and release encapsulated PolyP to enhance fibrin stability and augment hemostasis. Our principal innovation is in uniquely mimicking platelet's multi-step mechanisms of hemostasis on a single nanoconstruct.

血小板通过以下损伤部位选择性多步骤机制在止血中发挥核心作用：(1) 粘附 vWF 和胶原蛋白，(2) 纤维蛋白原介导的聚集形成初级止血塞，(3) 生物界面 将阴离子磷脂酰丝氨酸 (PS) 呈现在活化的血小板表面上以实现促凝血放大 凝血酶（因此是纤维蛋白），以及（4）血小板颗粒内容物的凝块局部分泌（例如无机物） 聚磷酸盐，PolyP）以局部增强纤维蛋白稳定性。这些机制受到严重损害 不可压缩性创伤性出血仍然是死亡的主要原因。 “黄金标准” 治疗此类出血的方法是大量输注全血或成分（血小板、血浆、红细胞）。 特别是，血小板输注在挽救创伤生命方面显示出巨大的临床益处。然而， 由于以下挑战，资源有限的医院和院前医院很少能提供血小板： 储存、便携、细菌污染风险高和保质期很短（约 5 天）。我们的目标是解决 通过设计基于生物材料的“人造血小板”纳米结构来应对这一挑战。为此，利用 之前的 R01 奖 (HL121212) 我们开发了自组装脂质肽纳米结构，可以模仿和 整合上述（1）和（2）的血小板机制。该设计显示了体外止血能力 在血小板减少小鼠尾部出血模型中，在严重创伤模型中效果有限。在此基础上， 我们现在建议通过设计独特的酶-在脂质体模板上模拟（3）和（4）的机制 响应性脂肽，随后将允许将所有四种机制整合到一个单一的 用于卓越的人造血小板设计的纳米结构。我们的中心假设是“模块化放大 通过模拟人工血小板内血小板的生物界面和分泌机制来止血 构建体可以显着减少出血并提高创伤中的存活率”。为了测试这一点，我们的具体目标 目的是： (1) 评估刺激（纤溶酶）触发的 PS 在脂质纳米结构上的暴露，以用于血小板启发 创伤中凝血酶（纤维蛋白）的特异性扩增； (2) 评估刺激（凝血酶）触发 释放无机多磷酸盐（PolyP）作为脂质纳米结构的有效负载，用于靶向损伤部位 纤维蛋白凝块的稳定； (3) 将这些独立的协同成分整合到人工血小板中 纳米结构评估啮齿动物创伤模型的止血功效和存活率。创伤性侮辱 血管内皮导致凝块处组织纤溶酶原激活剂（因此称为纤溶酶）的分泌增强 部位，导致纤维蛋白快速降解（纤溶亢进）并损害凝块稳定性。利用这个 纤溶酶将 PS 暴露在“人造血小板”表面将增强凝血酶（以及纤维蛋白）的生成 以抵消纤溶亢进。这种凝血酶还可以充当局部触发因素，破坏“人造血小板”的稳定性 构建并释放封装的 PolyP，以增强纤维蛋白稳定性并增强止血作用。我们的校长 创新在于在单个纳米结构上独特地模仿血小板的多步骤止血机制。