Microparticles as a Source of Nuclear Antigens in Systemic Lupus Erythematosus

描述（由申请人提供）：这些研究的目的是阐明微颗粒（MPs）作为系统性红斑狼疮（SLE）核抗原的关键来源的作用，并表征这些结构作为致病性免疫复合物（ic）的组成部分。MPs是细胞活化或死亡时从细胞中释放出来的小膜结构。这些颗粒含有DNA和RNA，这种形式可以保护细胞外核酸酶，并允许抗核抗体（ANAs）结合。因此，MPs可能形成免疫复合物，这些复合物要么沉积在组织中，要么促进包括干扰素- 1 （IFN）在内的细胞因子的产生。由于评估MPs作为SLE靶抗原及其效应功能的价值，我们正在提出研究以解决有关ANA与MPs结合的性质及其免疫效应的基本问题。提出了三个具体目标：1)分析抗核抗体与体外和体内模型系统以及患者血液循环中产生的MPs的结合。将分析患者血液中的MPs与一组单克隆抗dna和抗核小体抗体的结合；2)分析SLE患者血液中MPs的表达，重点关注结合抗体的颗粒，确定其与临床表现和疾病活动度的关系。使用狼疮患者的血浆，循环MPs将通过流式细胞术根据细胞表面标记物（包括结合Ig）进行量化。MPs的数量和性质与疾病活动性和器官特异性表现有关。SLE患者的血清也将被筛选是否与体外产生的颗粒结合；3)研究ANAs对体外系统微颗粒免疫活性的影响。MPs对巨噬细胞系和外周血细胞产生细胞因子的免疫作用将在体外评估，表征单克隆ANA和患者血清纯化的IgG的作用。总之，这些实验将为与SLE发病机制相关的一组新的亚细胞信号结构以及新的生物标志物和新疗法的发展提供重要的新信息。公共卫生相关性：这些研究将重点关注微颗粒在系统性红斑狼疮（SLE）中的作用，SLE是一种以多器官系统炎症和损伤为特征的原型自身免疫性疾病。这种疾病的一个重要机制与含有核酸的免疫复合物的形成和沉积有关。在这些研究中，我们将探讨细胞微粒作为这种核酸来源的作用。了解微粒在免疫复合物疾病中的作用将提供信息，允许开发新的治疗方法，以及评估SLE病程及其肾脏和血管并发症的标志物。

DESCRIPTION (provided by applicant): The goal of these investigations is to elucidate the role of microparticles (MPs) as a key source of nuclear antigens in systemic lupus erythematosus (SLE) and characterize these structures as components of pathogenic immune complexes (ICs). MPs are small membrane-structures that are released from cells during cell activation or death. These particles contain DNA and RNA in a form that is protected from extracellular nucleases and allows binding of antinuclear antibodies (ANAs). As such, MPs may form immune complexes that can either deposit in the tissue or promote cytokine production including interferon- 1 (IFN). Because of the value of assessing MPs as target antigens in SLE and their effector function, we are proposing studies to address fundamental questions concerning the nature of ANA binding to MPs and their immunological effects. Three specific aims are proposed: 1) To analyze the binding of antinuclear antibodies to MPs generated in in vitro and in vivo model systems as well as those circulating in patient blood. The MPs in patient blood will be analyzed for binding to a panel of monoclonal anti-DNA and anti- nucleosome antibodies; 2) To analyze the expression of MPs in the blood of patients with SLE, focusing on particles with bound antibody, and determine the relationship to clinical manifestations and disease activity. Using plasma from lupus patients, circulating MPs will be quantified by flow cytometry in terms of cell surface markers, including bound Ig. The number and properties of MPs will be related to disease activity and organ-specific manifestations. Sera of patients with SLE will also be screened for binding to the in vitro-generated particles; and 3) To investigate the effects of ANAs on the immunological activities of microparticles in in vitro systems. The immunological effects of MPs on cytokine production by macrophage cell lines and peripheral blood cells will be assessed in vitro, characterizing effects of monoclonal ANA as well as IgG purified by patient sera. Together, these experiments will provide important new information on a novel group of subcellular signaling structures relevant to the pathogenesis of SLE as well as the development of novel biomarkers and new therapies. PUBLIC HEALTH RELEVANCE: These studies will focus on the role of microparticles in systemic lupus erythematosus (SLE), a prototypic autoimmune disease characterized by inflammation and damage of multiple organ systems. An important mechanism of this disease concerns the formation and deposition of immune complexes that contain nucleic acids. In these studies, we will explore the role of cellular microparticles as a source of this nucleic acid. Understanding the role of microparticles in the immune complex disease will provide information to allow the development of new treatments as well as markers to assess the course of SLE and its renal and vascular complications.