The role of complement citrullination in RA pathogenesis

补体瓜氨酸化在 RA 发病机制中的作用

• 批准号: 9315724
• 负责人: Felipe Andrade
• 金额: $ 36.46万
• 依托单位: JOHNS HOPKINS UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-07-16 至 2021-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9315724
• 关键词: Address; Affect; Amplifiers; Antibodies; Antigens; Arthritis; Autoantibodies; Autoantigens; Autoimmune Process; B-Cell Activation; B-Lymphocytes; Biochemical; Biological Assay; Cells; Clinical; Complement; Complement Activation; Complement Factor H; Complement Membrane Attack Complex; Data; Deposition; Disease; Disease Outcome; Enzymes; Event; Feeds; Immune; Immune Targeting; Immune response; Immune system; Impairment; Infiltration; Inflammation; Inflammatory; Joints; Lytic; Mass Spectrum Analysis; Measures; Mediating; Modification; Outcome; Outcome Study; Pathogenesis; Pathogenicity; Pathway interactions; Patients; Post-Translational Protein Processing; Prevalence; Process; Production; Protein-arginine deiminase; Proteins; Publishing; Regulation; Rheumatism; Rheumatoid Arthritis; Role; Subgroup; Synovial Fluid; Synovial Membrane; Testing; Therapeutic Intervention; Tissues; To autoantigen; Vitronectin; Work; articular cartilage; bone erosion; cell injury; chronic autoimmune disease; citrullinated protein; clinically significant; cohort; complement C3d,g; complement system; feeding; genetic regulatory protein; in vitro Assay; in vivo; joint injury; multiple reaction monitoring; neutrophil; novel; response; targeted treatment

PROJECT SUMMARY/ABSTRACT Understanding the mechanisms which drive immune responses to autoantigens is of high priority. In rheumatoid arthritis (RA), protein citrullination is a major target of the immune system. Significant data implicates the anti-citrullinated protein immune response in RA pathogenesis, with recent evidence suggesting that mechanisms which enhance citrullination are associated with the worst disease outcome. While different mechanisms likely promote citrullination in RA, our published and preliminary data suggest that citrullination and the complement system are interacting pathways that amplify each other to enhance autoantigen production and immune-mediated damage in a sizable subset of RA patients. Thus, we have found that cellular membranolysis mediated by complement is a potent inducer of protein citrullination in the RA joint, and that this process is associated with citrullination of critical regulatory components of the complement system (complement factor H (CFH), and C3), enhancing complement activation. The previous finding that anti-CFH antibodies are prevalent in RA further highlights the importance of CFH in this disease, adding an extra mechanism that may dysregulate complement in RA. Taken together, we propose that citrullination-induced complement dysregulation and anti-CFH antibodies are key amplifiers that propagate damage and citrullination activity in the RA joint. We will examine this hypothesis in 3 Specific Aims. In Aim 1, we will use mass spectrometry and biochemical assays to define the structural and functional effects of citrullination on CFH and C3, as well as the effect of these modified proteins on the induction of the terminal complement complex, neutrophil hypercitrullination and B cell activation mediated by citrullinated C3dg. Aim 2 will use multiple reaction monitoring (MRM) to quantify citrullinated CFH and C3 in synovial fluid from RA and other arthritides to define their association with complement deposition and lytic activity in the joint. Aim 3 will determine whether anti-CFH antibodies participate in the dysregulation of complement in RA by defining their prevalence and clinical significance in RA, their association with complement activation, and their effect on CFH function. These studies will define novel interacting mechanisms of disease amplification relevant to sustain inflammation and aggravate damage in the rheumatoid joint. Furthermore, the studies will show that these pathways are active in vivo in RA, identifying markers and subgroups for precise therapeutic intervention.

项目概要/摘要 了解驱动针对自身抗原的免疫反应的机制是当务之急。在 类风湿性关节炎（RA）中，蛋白质瓜氨酸化是免疫系统的主要目标。重要数据 最近的证据表明，抗瓜氨酸蛋白免疫反应与 RA 发病机制有关 增强瓜氨酸化的机制与最糟糕的疾病结果相关。虽然不同 机制可能促进 RA 中的瓜氨酸化，我们发表的初步数据表明瓜氨酸化 补体系统是相互作用的途径，相互放大以增强自身抗原 相当一部分 RA 患者的产生和免疫介导的损伤。因此，我们发现细胞 补体介导的膜溶解是 RA 关节中蛋白质瓜氨酸化的有效诱导剂，并且 该过程与补体系统关键调节成分的瓜氨酸化有关 （补体因子 H (CFH) 和 C3），增强补体激活。先前的发现表明抗CFH 抗体在 RA 中普遍存在，进一步凸显了 CFH 在这种疾病中的重要性，增加了额外的 可能导致 RA 补体失调的机制。综上所述，我们建议瓜氨酸诱导的 补体失调和抗 CFH 抗体是传播损伤和瓜氨酸化的关键放大器 RA 关节的活动。我们将在 3 个具体目标中检验这一假设。在目标 1 中，我们将使用质量 光谱测定法和生化测定法来确定瓜氨酸化对 CFH 和功能的结构和功能影响 C3，以及这些修饰蛋白对末端补体复合物诱导的影响， 瓜氨酸化 C3dg 介导的中性粒细胞过度瓜氨酸化和 B 细胞激活。目标 2 将使用多个 反应监测 (MRM) 用于量化 RA 和其他关节炎滑液中的瓜氨酸 CFH 和 C3 以确定它们与关节中补体沉积和溶解活性的关联。目标 3 将决定 抗 CFH 抗体是否通过确定其患病率参与 RA 中的补体失调 RA 中的临床意义、与补体激活的关系以及对 CFH 功能的影响。 这些研究将定义与维持相关的疾病放大的新相互作用机制 炎症并加重类风湿关节的损伤。此外，研究将表明这些 通路在 RA 体内活跃，可识别标记物和亚组以进行精确的治疗干预。