Glycoprotein Ib in vascular biology and host defense

糖蛋白 Ib 在血管生物学和宿主防御中的作用

• 批准号: 9384693
• 负责人: Zaverio M Ruggeri
• 金额: $ 56.7万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-08-01 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9384693
• 关键词: Address; Adhesives; Affinity; Allergic Reaction; Anaphylaxis; Area; Attention; Binding; Biology; Blood; Blood Coagulation Factor; Blood Platelets; Blood Vessels; Bone Marrow; Cell Adhesion; Cells; Coagulation Process; Complement; Complex; Development; F2R gene; Factor-42; Functional disorder; Generations; Glycoprotein Ib; Goals; Hemorrhage; Hemostatic function; Homeostasis; Host Defense; Host Defense Mechanism; Hour; Human; Hypersensitivity; IgE; Immune; Immune response; Immunity; Infection; Inflammation; Inflammatory Response; Integrins; Knock-out; Knowledge; Leukocytes; Ligands; Link; Maintenance; Mediating; Megakaryocytes; Modeling; Molecular Conformation; Mouse Strains; Mus; Natural Immunity; P-Selectin; Peritoneal; Phenotype; Platelet Activation; Platelet Glycoproteins; Play; Process; Property; Proteinase-Activated Receptors; Proteins; Reaction; Research; Role; Shock; Species Specificity; Stimulus; Structure; Structure-Activity Relationship; Symptoms; Testing; Thrombin; Thrombosis; Tissues; Transfusion; Work; alpha-Thrombin; base; experimental study; fighting; immunoreaction; in vivo; innovation; insight; interest; mast cell; microorganism; mouse model; mutant; novel; oligomycin sensitivity-conferring protein; prevent; receptor; receptor expression; response; stem; tool; von Willebrand Factor

Project summary Our goal is to understand novel functions of the platelet glycoprotein (GP) Ib-IX-V complex, a key receptor for several ligands mediating, among others, adhesive interactions (mostly through von Willebrand factor), cell-cell contacts (interacting with leukocyte integrin αMβ2 and P-selectin) and coagulation (binding several coagulation factors including thrombin). With this project we intend to extend the understanding of GPIb physiopathologic relevance beyond megakaryocyte/platelet domains and more firmly into the area of innate immune mecha- nisms. Nonetheless, von Willebrand factor (VWF) and thrombin, key GPIb partners in hemostasis and throm- bosis, remain the main ligands of interest for the proposed new studies. In our work over nearly 30 years we have contributed to establish the bases for understanding how VWF, thrombin and GPIbα, the main subunit in the GPIbIX-V complex, interact. With respect to thrombin, even with the structure of the GPIbα-thrombin com- plex unveiled at atomic level detail, elucidating dependent functions has remained elusive. With the knowledge acquired through past studies and the ensuing generation of mice lacking thrombin-GPIb binding on platelets, and stimulated by surprising preliminary results obtained using these models, we propose two articulated spe- cific aims to develop a project addressing unexpected new functions. In aim 1 we will extend the effort to define the physiopathological significance of thrombin binding to platelet GPIbα developing two sub-aims. In the first, we will explore the functional roles of the newly identified high and low affinity thrombin-GPIbα binding modes, using for the purpose a mouse strain expressing a mutant human GPIbα (Y279F) in which high affinity throm- bin binding is lost but low affinity is retained. In the second, we will address the problem posed by the se- quence divergence between mouse and human GPIbα in the region of thrombin binding. We have identified the residues of mouse GPIbα required for thrombin binding and propose to generate a mouse model with en- dogenous mouse GPIbα selectively defective in thrombin binding but retaining all other ligand interactions with intact species specificity. This will be an essential tool to ascertain the value for human physiopathology of studying mechanisms of thrombin-induced platelet activation in mouse models with different PAR expression on platelets. In aim 2 we will characterize expression and function of GPIbα on mast cells and its functional role in anaphylaxis. We will develop two sub-aims. In the first we will characterize the structure of mast cell ex- pressed GPIb in relation to the other components of the GPIb-IX-V complex. In the second we will explore functions of mast cell expressed GPIbα evaluating roles in cell adhesion and in response to thrombin stimula- tion. We have already generated several new mouse models with defective GPIb expression on mast cells. The results of these studies will advance the understanding of mechanisms linking the function of platelets in hemostasis to relevant processes in inflammation, infection and innate immunity.

项目摘要 我们的目标是了解血小板糖蛋白（GP）Ib-IX-V复合物的新功能，Ib-IX-V复合物是一种关键的受体， 几种配体介导的粘附相互作用（主要通过血管性血友病因子），细胞-细胞 接触（与白细胞整合素αMβ2和P-选择素相互作用）和凝血（结合几种凝血 包括凝血酶在内的因子）。通过这个项目，我们打算扩展对GPIb生理病理学的理解， 相关性超出巨核细胞/血小板领域，更坚定地进入先天免疫机制领域， nisms。尽管如此，血管性血友病因子（VWF）和凝血酶，止血和凝血酶的关键GPIb伙伴， BOSIS仍然是所提出的新研究感兴趣的主要配体。在我们近30年的工作中， 为理解VWF，凝血酶和GPIbα（主要亚基）如何在血管内皮细胞中发挥作用奠定了基础。 GPIbIX-V复合物相互作用。对于凝血酶，即使具有GPIbα-凝血酶com-的结构， 在原子水平的细节揭示复杂，阐明相关功能仍然难以捉摸。的知识 通过过去的研究和随后一代缺乏血小板上凝血酶-GPIb结合的小鼠获得， 并受到使用这些模型获得的令人惊讶的初步结果的刺激，我们提出了两个铰接的spe- 该委员会旨在制定一个项目，处理意想不到的新功能。在目标1中，我们将努力定义 凝血酶与血小板GPIbα结合的病理生理学意义。在第一个， 我们将探索新发现的高亲和力和低亲和力凝血酶-GPIb α结合模式的功能作用， 使用表达突变型人GPIbα（Y279 F）的小鼠品系，其中高亲和力Throm-GlyB α（Y279 F）与人GPIbα（Y279 F）的结合， 箱结合丧失，但保持低亲和力。第二，我们将解决问题所造成的， 小鼠和人GPIbα在凝血酶结合区的序列差异我们已经确定 凝血酶结合所需的小鼠GPIbα的残基，并建议产生一个小鼠模型与en- 内源性小鼠GPIbα选择性缺陷凝血酶结合，但保留所有其他配体相互作用 完整的物种特异性。这将是一个必不可少的工具，以确定人类生理病理学的价值， 在不同PAR表达的小鼠模型中研究凝血酶诱导血小板活化的机制 血小板。目的2：研究GPIbα在肥大细胞上的表达和功能，并探讨其在肥大细胞中的作用。 在过敏反应中的作用。我们将制定两个次级目标。首先，我们将描述肥大细胞的结构， 相对于GPIb-IX-V复合物的其他组分按压GPIb。第二节我们将探讨 肥大细胞表达GPIbα的功能评估在细胞粘附和对凝血酶刺激的反应中的作用。 是的。我们已经产生了几个新的小鼠模型与缺陷的GPIb表达肥大细胞。 这些研究的结果将促进对血小板功能与糖尿病发病机制的理解。 止血与炎症、感染和先天免疫的相关过程有关。