Characterizing the proteome of pathogenic IgA1-containing immune complexes in IgA Nephropathy

IgA 肾病中致病性 IgA1 免疫复合物的蛋白质组特征

• 批准号: 10536410
• 负责人: Mary Cunningham
• 金额: $ 3.78万
• 依托单位: UNIVERSITY OF ALABAMA AT BIRMINGHAM
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-07-15 至 2024-07-14
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10536410
• 关键词: Antigen-Antibody Complex; Autoantibodies; Autoimmune; Awareness; Biological Markers; Blood; Blood Circulation; Blood Proteins; COVID-19; Calibration; Cell Proliferation; Chronic Kidney Failure; Clinical; Complement; Complement Activation; Complex; Data; Dedications; Deposition; Development; Diagnosis; Dialysis procedure; Disease; Evaluation; Fractionation; Fright; Future; Galactose; Glomerular Capillary; Glomerulonephritis; Goals; Health Care Costs; Human; IGA Glomerulonephritis; IgA1; IgG autoantibodies; Immune response; Immunocompromised Host; Immunoglobulin G; Immunoglobulins; Injury; Injury to Kidney; Isotope Labeling; J-Chain Immunoglobulins; Kidney; Kidney Diseases; Kidney Failure; Kidney Transplantation; Knowledge; Lead; Manuscripts; Measures; Methods; Modeling; Molecular; Molecular Weight; Pathogenesis; Pathogenicity; Pathologic; Patients; Peptides; Polymers; Population; Production; Prognostic Marker; Progressive Disease; Proteins; Proteome; Proteomics; Protocols documentation; Research; Research Personnel; Sampling; Serum; Stable Disease; Testing; Tissues; Urine; base; biobank; cost; innovation; kidney biopsy; mesangial cell; novel; pandemic disease; patient population; polymeric IgA; screening; stoichiometry; therapeutic target

Project Abstract IgA Nephropathy (IgAN) is an autoimmune glomerulonephritis that frequently results in kidney failure. IgAN is characterized by elevated production of galactose-deficient immunoglobulin A1 (Gd-IgA1) being bound by an immunoglobulin G (IgG) autoantibody specific for Gd-IgA1 to form IgA1-associated immune complexes (IgA1- ICs) with additional proteins in blood. These complexes deposit in the glomerulus and cause kidney injury by activating mesangial cell proliferation and breakdown of glomerular capillaries allowing protein or blood in the urine. There is no worldwide screening and can only be diagnosed by renal biopsy. We know that the immunoglobulins and the undefined blood proteins are necessary to the nephritogenic activity of the high molecular weight IgA1-ICs, but we do not know what concentration, and variability of each protein nor the ratio of immunoglobulins necessary for complex formation. The primary goal of my study is to quantify and establish the ratios of immunoglobulins and blood proteins in the composition of IgA1-ICs in the serum of patients with IgAN of opposing clinical spectrum in comparison to healthy controls. Our collaborative team has observed that the addition of serum to the immunoglobulin nucleating factors is necessary for the formation of pathogenic ICs that activate human cultured mesangial cells. The overarching goal of this proposal is that quantitative analysis of serum IgA1-ICs will determine stoichiometry of immunoglobulins and other blood proteins involved in the formation of IgA1-ICs in both progressing and stable disease patients with IgAN. In my recently submitted manuscript, I identified 21 high-quality blood protein targets specifically enriched in IgA1-ICs isolated from IgAN patient serum. When comparing the identification of proteins and their corresponding enrichment in the IgA1-ICs to the other uncomplexed forms of IgA1 control fractions (monomeric and polymeric IgA), we observed that each fraction clustered by molecular form, showing the value of our sample prep and innovative fractionation of serum. Based on preliminary data, I hypothesize the ratio of IgA1 to IgG autoantibody is discreet and can be determined by targeted LC-MS quantitative analysis, polymeric IgA1 is the predominant molecular form of IgA1 involved in complex formation and complement cascade activation factors are present in complex composition at a higher ratio than immunoglobulins before deposition into the kidney. Throughout the global pandemic, the world has learned of the importance of disease screening, the variability of disease presentation, and the daily fear that immunocompromised populations live in. Being a researcher in IgA Nephropathy, I have been aware of these realities in IgAN patient populations prior to COVID-19. This has fueled my dedication to answering important questions in the IgAN field and understanding this crucial part of pathogenesis of IgA1-IC formation for the sake of future development of less-invasive screening methods or therapies using blood biomarkers for this currently unpredictable disease.

项目摘要 IgA 肾病 (IgAN) 是一种自身免疫性肾小球肾炎，经常导致肾衰竭。 IgAN 是 其特征是缺乏半乳糖的免疫球蛋白 A1 (Gd-IgA1) 的产生增加，并与 免疫球蛋白 G (IgG) 特异性针对 Gd-IgA1 的自身抗体，形成 IgA1 相关免疫复合物 (IgA1- IC）与血液中的其他蛋白质。这些复合物沉积在肾小球中并通过以下方式引起肾损伤： 激活系膜细胞增殖和肾小球毛细血管破裂，使蛋白质或血液进入肾小球 尿。世界范围内尚无筛查，只能通过肾活检确诊。我们知道 免疫球蛋白和未定义的血液蛋白对于高肾炎活性是必需的 IgA1-IC 的分子量，但我们不知道每种蛋白质的浓度和变异性，也不知道比例 复合物形成所必需的免疫球蛋白。我研究的主要目标是量化和建立 患者血清中 IgA1-IC 成分中免疫球蛋白与血液蛋白的比例 与健康对照相比，IgAN 具有相反的临床谱。我们的协作团队观察到 免疫球蛋白成核因子中添加血清对于致病性 IC 的形成是必要的 激活人类培养的系膜细胞。该提案的总体目标是定量分析 血清 IgA1-IC 的变化将决定免疫球蛋白和参与免疫反应的其他血液蛋白的化学计量。 IgAN 进展期和稳定期患者中 IgA1-IC 的形成。在我最近提交的 手稿中，我鉴定了 21 个高质量的血液蛋白靶标，这些靶标富含从 IgAN 中分离出的 IgA1-IC 患者血清。比较 IgA1-IC 中蛋白质的鉴定及其相应的富集度时 与其他未复合形式的 IgA1 对照组分（单体和聚合 IgA）相比，我们观察到每个 按分子形式聚集的级分，显示了我们的样品制备和创新的血清分级分离的价值。 根据初步数据，我假设 IgA1 与 IgG 自身抗体的比率是谨慎的并且可以确定 通过靶向 LC-MS 定量分析，聚合 IgA1 是 IgA1 的主要分子形式，参与 复合物形成和补体级联激活因子以较高的浓度存在于复合物组合物中 比沉积到肾脏之前的免疫球蛋白的比率。纵观全球疫情大流行，世界各地 了解了疾病筛查的重要性、疾病表现的多样性以及每天的恐惧 作为 IgA 肾病的研究者，我已经意识到这些 COVID-19 之前 IgAN 患者群体的现实情况。这促使我致力于回答重要的问题 IgAN 领域的问题并了解 IgA1-IC 形成发病机制的关键部分 目前使用血液生物标志物的微创筛查方法或疗法的未来发展 不可预测的疾病。