Investigating the functional capacity of autoantibodies in primary membranous nephropathy

研究原发性膜性肾病自身抗体的功能能力

• 批准号: 10297617
• 负责人: Laurence H Beck
• 金额: $ 26.25万
• 依托单位: BOSTON MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-20 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10297617
• 关键词: Achievement; Activities of Daily Living; Address; Animals; Antibodies; Antibody titer measurement; Antigen Targeting; Antigen-Antibody Complex; Antigens; Autoantibodies; Autoimmune; Binding; Biological Assay; Biopsy; Blood Tests; Cell Line; Cells; Clinical; Clinical Data; Complement; Complement 3c; Complement Activation; Cox Proportional Hazards Models; Deposition; Development; Diagnosis; Disease; Disease Outcome; Disease Pathway; Disease remission; Elements; End stage renal failure; Enzyme-Linked Immunosorbent Assay; Epitope spreading; Epitopes; Event; Extracellular Matrix; Filtration; Gene Expression; Generations; Glomerulonephritis; Goals; Guidelines; Human; Immune; Immune System Diseases; Immunoblotting; Immunodominant Epitopes; Immunoglobulin G; Immunologic Monitoring; Immunological Diagnosis; Immunosuppression; Immunotherapy; Injury; Kidney; Kidney Diseases; Knowledge; Laboratories; Lead; Measures; Mediating; Medical; Membranous Glomerulonephritis; Methods; Molecular; Monitor; N-terminal; Nephrology; Nephrotic Syndrome; Outcome; Pathogenicity; Pathologic; Patients; Production; Property; Proteins; Proteinuria; Reaction; Recombinants; Recovery; Renal function; Risk; Sampling; Serology; Serology test; Serum; Severities; Severity of illness; Specificity; Specimen; Spontaneous Remission; Survival Analysis; Testing; Time; Tissues; Transforming Growth Factor beta; Work; aggressive therapy; base; care providers; cell injury; clinical predictors; clinical remission; cohort; crosslink; glomerular basement membrane; human disease; in vitro Model; in vivo; individual patient; injured; insight; kidney biopsy; novel; podocyte; primary outcome; prognostic; targeted treatment; treatment response

PROJECT SUMMARY / ABSTRACT Membranous nephropathy (MN) is an autoimmune kidney disease in which antibodies against intrinsic glomerular proteins expressed by the podocyte lead to sublethal podocyte cell injury, loss of the filtration barrier, and ultimately the nephrotic syndrome. The overall disease course can be quite protracted and the duration and extent of proteinuria are risks for progressive decline of kidney function and end-stage kidney disease. PLA2R is the major target in 80% of primary MN cases and the monitoring of circulating anti-PLA2R antibodies (PLA2R- ab) has been instrumental in following immunologic disease activity and allowing for more rapid treatment decisions. Yet despite the existence of guidelines for such use of PLA2R-ab serology, nephrologists continue to have substantial ambiguity about whom to treat with immunosuppression, and when, due to significant variability in outcome. Patients may develop severe nephrotic syndrome with relatively low titers of PLA2R-ab or relatively mild disease with very high levels, an observation which remains unexplained. The goal of this proposal is to identify novel predictors of disease outcome associated with the variable repertoire of PLA2R-ab (which differ in subclass and epitope specificity) and to better understand the functional consequences of PLA2R-ab-mediated injury. Aim 1 describes the development of two novel assays that may add to total PLA2R-ab titer in determining likelihood of clinical remission. One assay will be a simple ELISA to assess the absence or presence of epitope spreading beyond the N-terminal immunodominant epitope of PLA2R. The second will be a measure of C3c generation (complement activation) by PLA2R-ab to summate the functional effects of all the IgG subclasses and epitope specificities. Cox proportional hazards models (survival analysis) will be used to test the associations between PLA2R-ab levels, C3c generation and epitope spreading with time to the primary outcome (achievement of partial or complete remission), using two well-characterized MN cohorts. Aim 2 will use IgG eluted from remnant kidney biopsies from patients with MN to ask whether or not the repertoire of PLA2R-ab that is bound within the immune deposits mirrors the circulating forms. The manner by which PLA2R is attached within the glomerular basement membrane (GBM) will also be assessed. Understanding the pathogenic PLA2R-ab that accumulate with antigen in the kidney deposits, as well as knowing how PLA2R is incorporated into deposits may offer new insights into disease pathways that could be targeted therapeutically. It has been suggested from animal studies that the extracellular matrix produced in reaction to the immune injury in MN contains ectopic elements not usually present in healthy GBM; these have not been extensively studied in human disease. In Aim 3, PLA2R-expressing human podocytes will serve as an in vitro model of PLA2R-ab-induced cell injury to assess early events that lead to antibody-mediated release of PLA2R from the cell, its binding to conventional and more novel matrix elements, and to broadly look at changes in extracellular matrix production. The new knowledge gained from these studies will expand our knowledge of how deposits form and persist in human MN.

项目摘要 /摘要 膜性肾病（MN）是一种自身免疫性肾脏疾病，抗体抗体 由足细胞表达的肾小球蛋白会导致上肌足细胞损伤，过滤屏障的丧失， 并最终患有肾病综合征。总体疾病病程可以很长时间，持续时间和 蛋白尿的程度是肾功能和终末期肾脏疾病逐渐下降的风险。 pla2r 是80％的主要MN病例的主要目标，并且监测循环抗Pla2r抗体（PLA2R- AB）在遵循免疫疾病活动并允许更快的治疗方面发挥了作用 决定。尽管存在使用PLA2R-AB血清学的指南，但肾脏科医生仍在继续 对通过免疫抑制处理谁以及由于重大可变性而具有很大的歧义 在结果中。患者可能患有严重的肾病综合征，具有相对较低的pla2r-ab或相对较低的 温和的疾病非常高，这种观察仍然无法解释。该提议的目的是 确定与PLA2R-AB可变库相关的疾病预后的新预测指标 子类和表位特异性），以更好地了解PLA2R-AB介导的功能后果 受伤。 AIM 1描述了两个新颖的测定的开发 临床缓解的可能性。一种测定将是评估表位的不存在或存在的简单ELISA 扩展超出PLA2R的N末端免疫主导表位。第二个将是C3C的量度 通过PLA2R-AB生成（补充激活）来汇总所有IgG亚类的功能效应 和表位特异性。 COX比例危害模型（生存分析）将用于测试关联 在PLA2R-AB级别之间，C3C的产生和表位随时间扩散到主要结果（成就 使用两个特征良好的MN队列的部分或完全缓解）。 AIM 2将使用从中洗脱的IgG 来自MN患者的残留肾脏活检，询问是否绑定了PLA2R-AB的曲目 免疫沉积物内部反映了循环形式。 PLA2R附着在 肾小球基底膜（GBM）也将进行评估。了解致病性PLA2R-AB 用抗原在肾脏沉积物中积聚，并知道如何将PLA2R纳入沉积物中 可能会提供有关疾病途径的新见解。从 动物研究表明，针对MN免疫损伤的反应产生的细胞外基质包含异位 元素通常不存在于健康的GBM中；这些尚未在人类疾病中进行广泛研究。目标 3，表达PLA2R的人足细胞将作为PLA2R-AB诱导的细胞损伤的体外模型，以评估 导致抗体介导的PLA2R从细胞释放的早期事件，其与常规和更多的结合 新颖的矩阵元素，并广泛研究细胞外基质产生的变化。新知识 从这些研究中获得的将扩大我们对人类元中存款和持续存在如何形成和持续存在的知识。