Modeling the spectrum of HIT pathobiology

HIT 病理学谱系建模

• 批准号: 8464632
• 负责人: Gowthami M Arepally
• 金额: $ 7.85万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-05-01 至 2014-10-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8464632
• 关键词: Allergic Reaction; Animal Model; Antibodies; Antibody Formation; Anticoagulants; Antigens; Applications Grants; Binding; Blood Platelets; C57BL/6 Mouse; Cells; Characteristics; Clinical; Coagulation Process; Collaborations; Complex; Complication; Development; Disease; Drug Formulations; Evolution; Exposure to; Fc Receptor; Future; Goals; Heparin; Human; Hypersensitivity; Immune; Immune System Diseases; Immune response; Immunization; In Vitro; Investigation; Laboratories; Life; Low-Molecular-Weight Heparin; Mediating; Modeling; Monoclonal Antibodies; Morbidity - disease rate; Mus; Pathogenesis; Pathogenicity; Patients; Pharmaceutical Preparations; Platelet Activation; Platelet Factor 4; Property; Proteins; Relative (related person); Research Methodology; Research Project Grants; Risk Factors; Role; Study models; Testing; Thrombocytopenia; Thrombosis; Transgenic Mice; Transgenic Model; Venous Thrombosis; allergic response; base; clinically relevant; crosslink; fondaparinux; immunogenic; immunogenicity; in vivo; mortality; prevent; receptor; research study

DESCRIPTION (provided by applicant): The goal of this small grant application is to develop a research methodology for studies of Heparin-Induced Thrombocytopenia (HIT). HIT is a prothrombotic disorder caused by an allergic response to the anticoagulant drug, heparin. HIT is caused by antibodies directed towards a platelet protein, Platelet Factor 4 (PF4) and heparin (H). Because PF4/H antibodies can elicit life-threatening thrombotic complications in patients, experimental studies of disease pathogenesis have relied on animal models. Two distinct animal models have been developed to study HIT; one model studies thrombotic complications of HIT (murine HIT model) and the other, a murine immunization model developed by our lab to study the PF4/H immune response. In this R03 application, we propose to develop an integrated murine model for studies of human HIT pathogenesis. Based on preliminary studies, we hypothesize that pathogenicity of PF4/H antibodies is determined by the confluence of three factors, circulating antigen (PF4/H complexes), PF4/H Abs and activating platelet Fc RIIA receptors. We propose to test this hypothesis using one of two approaches relying on the presence of Fc RIIA expression (single transgenic model) with or without expression of hPF4 (double transgenic model). In the first approach, we will induce PF4/H antibodies in a single transgenic model (mice expressing hFc RIIA) with the goal of examining effects of antigen load, antibody titer and Fc RII expression. In the second approach, we wish to develop a "humanized" murine model using double transgenic mice expressing human (h)PF4 and hFc RIIA to examine the effects of hPF4 levels and hFcR expression on the immune response and disease expression. In pursuing this small research grant, we hope that these optimized murine models will facilitate future investigations on the mechanisms underlying evolution of pathogenic HIT antibodies.

描述（由申请人提供）：这项小额赠款申请的目标是开发一种研究肝素诱导的血小板减少症 (HIT) 的研究方法。 HIT 是一种由抗凝药物肝素过敏反应引起的血栓前性疾病。 HIT 是由针对血小板蛋白、血小板因子 4 (PF4) 和肝素 (H) 的抗体引起的。由于 PF4/H 抗体可引起患者危及生命的血栓并发症，因此疾病发病机制的实验研究依赖于动物模型。已经开发出两种不同的动物模型来研究 HIT；一个模型研究 HIT 的血栓并发症（小鼠 HIT 模型），另一个模型是我们实验室开发的用于研究 PF4/H 免疫反应的小鼠免疫模型。在此 R03 应用中，我们建议开发一种综合小鼠模型来研究人类 HIT 发病机制。基于初步研究，我们假设 PF4/H 抗体的致病性是由循环抗原（PF4/H 复合物）、PF4/H Ab 和激活血小板 Fc RIIA 受体这三个因素共同决定的。我们建议使用两种方法之一来测试这一假设，这两种方法依赖于 Fc RIIA 表达（单转基因模型）的存在，有或没有 hPF4 的表达（双转基因模型）。在第一种方法中，我们将在单一转基因模型（表达 hFc RIIA 的小鼠）中诱导 PF4/H 抗体，目的是检查抗原负载、抗体滴度和 Fc RII 表达的影响。在第二种方法中，我们希望使用表达人(h)PF4和hFc RIIA的双转基因小鼠开发“人源化”小鼠模型，以检查hPF4水平和hFcR表达对免疫反应和疾病表达的影响。在争取这笔小额研究资助的过程中，我们希望这些优化的小鼠模型将有助于未来对致病性 HIT 抗体进化机制的研究。