Microparticles as a Source of Nuclear Antigens in Systemic Lupus Erythematosus

描述(申请人提供)：这些研究的目的是阐明微粒(MP)在系统性红斑狼疮(SLE)中作为核抗原的关键来源的作用，并将这些结构表征为致病免疫复合体(IC)的组成部分。MPS是一种小的膜结构，在细胞激活或死亡过程中从细胞中释放出来。这些颗粒含有DNA和RNA，这种形式不受细胞外核酸酶的保护，并允许抗核抗体(ANA)的结合。因此，MPS可以形成免疫复合体，既可以沉积在组织中，也可以促进细胞因子的产生，包括干扰素-1(干扰素)。由于评估MPS作为SLE的靶抗原及其效应器功能的价值，我们建议进行研究，以解决有关ANA与MPS结合的性质及其免疫学效应的基本问题。提出了三个具体的目标：1)分析体外和体内模型系统中产生的抗核抗体与MPS的结合以及患者血液中循环的MPS。将分析患者血液中的MPS是否与一组单抗DNA和抗核小体抗体结合；2)分析SLE患者血液中MPS的表达，重点分析具有结合抗体的颗粒，并确定其与临床表现和疾病活动性的关系。使用狼疮患者的血浆，循环MPS将通过流式细胞仪根据细胞表面标志物，包括结合的Ig来定量。MPS的数量和性质将与疾病活动和器官特异性表现有关。还将筛选SLE患者的血清与体外产生的颗粒结合；以及3)研究Anas在体外系统中对微粒免疫活性的影响。MPS对巨噬细胞系和外周血细胞产生细胞因子的免疫学效应将在体外进行评估，以确定单抗ANA和患者血清纯化的免疫球蛋白的作用。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生物标记物和新疗法的开发提供重要的新信息。公共卫生相关性：这些研究将集中在微粒在系统性红斑狼疮(SLE)中的作用，SLE是一种典型的自身免疫性疾病，以多器官系统的炎症和损害为特征。这种疾病的一个重要机制与含有核酸的免疫复合体的形成和沉积有关。在这些研究中，我们将探索细胞微粒作为这种核酸来源的作用。了解微粒在免疫复合体疾病中的作用将提供信息，以便开发新的治疗方法，以及评估SLE及其肾脏和血管并发症的标记物。

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.