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

基本信息

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
项目类别：
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

项目摘要

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.

项目概要/摘要膜性肾病（MN）是一种自身免疫性肾病，其中抗内在抗体足细胞表达的肾小球蛋白导致亚致死的足细胞损伤、滤过屏障丧失、最终导致肾病综合征。整个病程可能相当漫长，持续时间和蛋白尿的程度是肾功能进行性衰退和终末期肾病的风险。 PLA2R 是 80% 原发性 MN 病例的主要目标，也是监测循环抗 PLA2R 抗体（PLA2R- ab) 在跟踪免疫疾病活动和实现更快速的治疗方面发挥了重要作用决定。然而，尽管存在有关使用 PLA2R-ab 血清学的指南，肾脏病学家仍然继续由于显着的可变性，对于谁应该接受免疫抑制治疗以及何时接受免疫抑制治疗存在很大的模糊性在结果中。患者可能会出现严重肾病综合征，PLA2R-ab 滴度相对较低或相对较高。轻度疾病，但水平非常高，这一观察结果仍无法解释。该提案的目标是确定与 PLA2R-ab 的可变组库相关的疾病结果的新预测因子（其不同之处在于亚类和表位特异性）并更好地了解 PLA2R-ab 介导的功能后果受伤。目标 1 描述了两种新测定法的开发，这些测定法可能会增加总 PLA2R-ab 滴度以确定临床缓解的可能性。一种检测是简单的 ELISA，用于评估表位是否存在扩散到 PLA2R N 端免疫显性表位之外。第二个是 C3c 的衡量标准 PLA2R-ab 生成（补体激活）以总结所有 IgG 亚类的功能效果和表位特异性。 Cox 比例风险模型（生存分析）将用于测试关联性 PLA2R-ab 水平、C3c 生成和表位随时间扩散到主要结果（成就部分或完全缓解），使用两个特征良好的 MN 队列。目标 2 将使用从 MN 患者的残余肾活检，以询问是否结合了 PLA2R-ab 的所有成分免疫沉积物内反映了循环形式。 PLA2R 在内部的附着方式肾小球基底膜（GBM）也将被评估。了解致病性 PLA2R-ab 抗原在肾脏沉积物中积累，并了解 PLA2R 如何融入沉积物中可能会为可靶向治疗的疾病途径提供新的见解。已建议从动物研究表明 MN 对免疫损伤反应产生的细胞外基质含有异位健康 GBM 中通常不存在的元素；这些尚未在人类疾病中得到广泛研究。瞄准 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来评估导致抗体介导的 PLA2R 从细胞中释放、其与常规等的结合的早期事件新颖的基质元素，并广泛观察细胞外基质产生的变化。新知识从这些研究中获得的成果将扩大我们对沉积物如何在人类微核中形成和持续存在的认识。