Platelets and complement in antibody-mediated rejection

抗体介导的排斥反应中的血小板和补体

基本信息

批准号：
9283289
负责人：
William M Baldwin
金额：
$ 39.02万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
2010
资助国家：
美国
起止时间：
2010-06-08 至 2020-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9283289
关键词：
Acute Allografting Antibodies Antigens Apoptosis Autoantigens Binding Biological Markers Biopsy Blood Platelets Blood Vessels Characteristics Chemotaxis Chronic Cleaved cell Clinical Research Complement Complement Inactivators Data Endothelial Cells Epitopes Extracellular Matrix Proteins Fibrosis Functional disorder Funding Glycosaminoglycans Goals Human Hyaluronan Hyaluronidase IL8 gene Impairment In Vitro Inflammation Inflammatory Injury Kidney Transplantation Lesion Leukocytes Lupus Macrophage Activation Mediating Mediator of activation protein Modeling P-Selectin PF4 Gene Pathologic Patients Platelet Activation Protocols documentation RANTES Recruitment Activity Reporting Rheumatoid Arthritis Role Serotonin Signal Transduction Site Testing Therapeutic Intervention Toll-like receptors VWF gene Vascular Diseases Vascular Endothelium Vascular Permeabilities base chemokine clinically relevant in vivo Model inhibitor/antagonist kidney allograft macrophage monocyte mouse model response von Willebrand Factor

项目摘要

Project Summary / Abstract Antibodies are a major cause of acute and chronic rejection in renal transplants. Some pathologic manifestations of acute antibody-mediated rejection (AMR) that has progressed to graft dysfunction have been defined. However, it is evident that not all of the mediators of AMR have been identified. The potentially reversible stages that precede graft impairment are difficult to resolve in clinical studies even with protocol biopsies because of uncontrollable variables inherent among patients. We have used in vitro and in vivo models to demonstrate that antibodies stimulate endothelial cells to exocytose von Willebrand factor and P- selectin. We propose that activated platelets have critical functions in early AMR and greatly expand inflammation by interacting with endothelial cells and leukocytes. We reported that platelet factor 4 and serotonin accumulated in renal allografts at 100- to 1000-fold higher concentrations compared with other platelet-transported mediators. The localization of large quantities of platelet factor 4 in the allograft has multiple consequences on macrophage function. These interactions are particularly relevant because macrophage infiltrates in human biopsies are a characteristic of AMR. Release of serotonin from platelets also has potential to recruit leukocytes to renal transplants. In addition, platelets can stimulate monocytes and macrophages indirectly at sites of inflammation where endothelial cells release increased amounts of the extracellular matrix protein hyaluronan. Hyaluronidase 2 expressed by activated platelets cleaves HA into fragments that act as danger signals to stimulate macrophages through toll like receptors. The potential beneficial effects of modulating platelet activation in AMR have not been tested fully. In addition to blocking specific platelet mediators, we have found that clinically relevant complement inhibitors are one approach to decrease platelet localization in allografts. We propose the hypothesis that antibodies initiate platelet and endothelial responses that augment leukocyte interactions with blood vessels in renal transplants during AMR. We will test this hypothesis in 3 specific aims: 1) Test the role of platelet-derived mediators in directly causing injury to renal transplants; 2) Test the multiple effects of C1 inhibitor on recruitment and activation of platelets and macrophages; and 3) Test the role of hyaluronan released by vascular endothelium and cleaved by platelets in augmenting inflammation and contributing to fibrosis in renal transplants. To accomplish these specific aims, we will use mouse models of AMR in renal transplants that have been developed by Drs. Fairchild and Valujskikh in Projects 1 and 3 in the previous funding period as well as the passive transfer models developed in our Project 2. Our goals for each specific aim are to understand mechanisms by which platelets contribute to AMR, identify biomarkers of platelet-induced injury and test potential therapeutic interventions.

项目概要/摘要抗体是肾移植中急性和慢性排斥反应的主要原因。有些病理性的已进展为移植物功能障碍的急性抗体介导的排斥反应（AMR）的表现定义的。然而，显然并非所有抗菌素耐药性的介体都已被识别。潜在的即使有方案，移植物损伤之前的可逆阶段在临床研究中也很难解决由于患者固有的不可控变量而进行活检。我们已经在体外和体内使用模型证明抗体刺激内皮细胞胞吐冯维勒布兰德因子和 P- 选择素。我们认为活化的血小板在早期 AMR 中具有关键功能，并可大大扩展通过与内皮细胞和白细胞相互作用而产生炎症。我们报道了血小板因子 4 和与其他肾移植物相比，同种异体肾移植物中血清素的积累浓度高出 100 至 1000 倍血小板转运介质。大量血小板因子 4 在同种异体移植物中的定位对巨噬细胞功能的多重影响。这些相互作用特别重要，因为人体活检中巨噬细胞浸润是 AMR 的一个特征。血小板也释放血清素有潜力招募白细胞进行肾移植。此外，血小板还能刺激单核细胞巨噬细胞间接作用于炎症部位，内皮细胞释放更多的巨噬细胞细胞外基质蛋白透明质酸。活化血小板表达的透明质酸酶 2 将 HA 裂解成作为危险信号的碎片通过收费样受体刺激巨噬细胞。潜力调节血小板活化对 AMR 的有益作用尚未得到充分测试。除了拦截之外针对特定的血小板介质，我们发现临床相关的补体抑制剂是一种方法减少同种异体移植物中的血小板定位。我们提出这样的假设：抗体启动血小板和肾移植中增强白细胞与血管相互作用的内皮反应在 AMR 期间。我们将在 3 个具体目标中检验这一假设：1) 检验血小板衍生介质在直接造成肾移植损伤； 2) 测试C1抑制剂对招募和招募的多重影响血小板和巨噬细胞的激活； 3) 测试血管内皮释放的透明质酸的作用并被血小板裂解，从而加剧炎症并导致肾移植中的纤维化。到为了实现这些具体目标，我们将在肾移植中使用 AMR 小鼠模型，这些模型已在由博士开发。 Fairchild 和 Valujskikh 在上一资助期的项目 1 和 3 以及我们的项目 2 中开发的被动传输模型。我们每个具体目标的目标是了解血小板促进 AMR 的机制，识别血小板诱导损伤的生物标志物，以及测试潜在的治疗干预措施。