Fibrinogen and Factor XIII in Venous Thrombosis

静脉血栓形成中的纤维蛋白原和因子 XIII

• 批准号: 9205251
• 负责人: Alisa S. Wolberg
• 金额: $ 37.63万
• 依托单位: UNIV OF NORTH CAROLINA CHAPEL HILL
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-01-15 至 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9205251
• 关键词: Affect; American; Anticoagulation; Autopsy; Binding; Biochemical Genetics; Biological Assay; Biological Models; Blood coagulation; Characteristics; Clinical; Coagulation Process; Data; Deposition; Development; Edema; Electrons; Erythrocytes; Factor XIII; Factor Xa; Fibrin; Fibrinogen; Functional disorder; Goals; Hemorrhage; Hemostatic function; Human; Image; In Vitro; Left; Leg Ulcer; Mediating; Medical; Mission; Modeling; Molecular; Morbidity - disease rate; Patients; Peptides; Pharmacology; Phase; Plasma; Polymers; Postphlebitic Syndrome; Process; Production; Public Health; Recombinant Proteins; Recurrence; Research; Risk; Role; Testing; Thrombin; Thrombosis; Thrombus; Ulcer; Ultrasonography; United States National Institutes of Health; Venous; Venous Thrombosis; Whole Blood; Work; analytical method; animal imaging; chronic pain; clinically significant; crosslink; human disease; improved; in vivo; in vivo Model; innovation; intravital microscopy; knowledge base; mouse model; new therapeutic target; next generation; novel strategies; prevent; public health relevance; targeted treatment; tool; transmission process

 DESCRIPTION (provided by applicant): Venous thrombosis (VT) affects over 1 million Americans annually. Even with treatment, 30-50% of VT patients develops recurrent VT or suffer debilitating long-term morbidity including chronic pain, edema, and ulcers (so- called "post-thrombotic syndrome"). Current anticoagulation therapies target factor Xa or thrombin and are associated with a significant risk of catastrophic bleeding. The development of next generation agents which reduce thrombosis without increasing the risk of hemorrhage, would have a profound impact on this significant clinical problem. The defining characteristics of venous "red" thrombi are their high red blood cell (RBC) and fibrin content. The existing paradigm suggests RBCs are passively trapped in the clot during fibrin polymer formation. However, we have recently discovered that factor XIII (FXIII) mediates RBC retention in clots and determines clot size. We have also identified fibrinogen residues that promote interactions with FXIII and are required for normal FXIII activation and fibrin crosslinking. Importantly, we have shown that inhibiting FXIIIa activity or blocking FXIII-fibrinogen interactions reduces clot RBC content, and consequently, significantly reduces thrombus size in vitro and in vivo. These exciting discoveries suggest that inhibiting FXIII or blocking FXIII-fibrinogen interactions represent entirely new and novel strategies for reducing VT. The goal of this application is to determine the molecular mechanisms by which FXIII and fibrinogen mediate VT. The overall hypothesis is that FXIII(a) activity mediates RBC retention in clots. Thus, inhibiting FXIII activiy or disrupting the interaction between FXIII and fibrinogen will reduce VT. This hypothesis will be tested in three Specific Aims: 1) Define the fibrinogen residues required for FXIII binding and determine whether peptides that disrupt FXIII interactions with fibrinogen decrease RBC retention in clots, 2) Determine whether FXIIIa promotes RBC retention in clots via fibrin crosslinking, and 3) Determine the role of FXIII and effect of FXIII(a) inhibition in VT and hemostasis. This study will employ biochemical, genetic and pharmacologic tools to define the FXIII- fibrinogen axis and determine the role of FXIII activity and RBC retention during whole blood clot formation. FXIII-fibrinogen interactions and FXIIIa function will be examined using recombinant proteins, solution phase binding assays, and innovative fibrin analytical methods. Clot formation will be studied using in vitro and in vivo models of VT and hemostasis, including live-animal imaging (e.g., ultrasound imaging and intravital microscopy). These studies will significantly expand our understanding of newly-recognized roles for FXIII(a) and fibrinogen in thrombus formation and stability. This study is highly innovative because it challenges the current paradigm that RBCs are passively entangled in thrombi and proposes that thrombus RBC content can be reduced to prevent VT. The proposed research is clinically significant because it may reveal an entirely new strategy to reduce VT.

 描述（适用提供）：静脉血栓形成（VT）每年影响超过100万美国人。即使接受治疗，有30％至50％的VT患者仍会发展出复发性VT或遭受使人衰弱的长期发病率，包括慢性疼痛，水肿和溃疡（所谓的“后栓性综合征”）。当前的抗凝疗法靶向Xa或凝血酶，并与灾难性出血的显着风险有关。下一代药物的开发减少血栓形成而不增加出血风险，将对这个重大的临床问题产生深远的影响。静脉“红色”血栓的定义特征是它们的高红细胞（RBC）和纤维蛋白含量。现有的范式表明，在纤维蛋白聚合物形成期间，RBC被动地被凝块被捕。但是，我们最近发现，XIII（FXIII）介导了凝块中的RBC保留率并确定凝块大小。我们还确定了纤维蛋白原保留的促进与FXIII相互作用的纤维蛋白原保留，并且是正常的FXIII激活和纤维蛋白交联所必需的。重要的是，我们已经表明，抑制FXIIIA活性或阻断FXIII-纤维蛋白原相互作用会减少凝块RBC含量，因此显着降低了体外和体内血栓大小。这些令人兴奋的发现表明，抑制FXIII或阻塞FXIII-纤维蛋白原相互作用代表了减少VT的全新新颖策略。该应用的目的是确定FXIII和纤维蛋白原介导VT的分子机制。总体假设是FXIII（A）活性介导了布料中的RBC保留率。抑制FXIII活动或破坏FXIII和纤维蛋白原之间的相互作用将减少VT。该假设将以三个特定的目的进行检验：1）定义FXIII结合所需的纤维蛋白原保留，并确定是否破坏FXIII相互作用与纤维蛋白下降的肽是否与纤维蛋白下降的RBC保留率是否在簇中保留，2）确定FXIIIA是否通过FXII促进Clusii crossii crossii and flx a和3 fors for f x a for f xiiia clusters clusters in Clusii and 3） VT和止血的抑制作用。这项研究将采用生化，遗传和药物工具来定义FXIII-纤维蛋白原轴，并确定全血凝块形成过程中FXIII活性和RBC保留的作用。 FXIII-纤维蛋白原相互作用和FXIIIA功能将使用重组蛋白，溶液相结合测定和创新的纤维蛋白分析方法检查。将使用VT和止血的体外和体内模型研究凝块的形成，包括活动画成像（例如，超声成像和浸润显微镜）。这些研究将大大扩展我们对新认识到的FXIII（A）和纤维蛋白原在血栓形成和稳定性中的理解。这项研究具有很高的创新性，因为它挑战了当前RBC被动地纠缠在血栓中的范式，并且提议可以减少血栓RBC含量以防止VT。