Molecular Basis of Pathogenicity of IgA1-containing Immune Complexes

含 IgA1 的免疫复合物致病性的分子基础

基本信息

批准号：
9111852
负责人：
JAN NOVAK
金额：
$ 21.98万
依托单位：
UNIVERSITY OF ALABAMA AT BIRMINGHAM
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-06-01 至 2019-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9111852
关键词：
Animal Model Antibodies Antigen-Antibody Complex Autoantibodies Binding Biological Assay Cell Line Cell Proliferation Cells Characteristics Chronic Clinical Clinical Investigator Clinical Research Complex Data Deposition Detection Development Disease Dose End stage renal failure Engineering Event Extracellular Matrix Proteins Frequencies Functional disorder Galactose Glomerulonephritis Health Heterogeneity Histologic Human IgA1 Immune Immunoglobulin A Immunoglobulin G Immunoglobulin Variable Region In Vitro Integrins KDR gene Kidney Kidney Diseases Kidney Failure Lead Light Mediating Modeling Molecular Molecular Analysis Molecular Profiling PDGFRB gene Pathogenesis Pathogenicity Pathway interactions Patients Peptides Pharmaceutical Preparations Phenotype Phosphotransferases Polysaccharides Prevention Prognostic Marker Proliferating Protein Kinase Protein Kinase Inhibitors Protein Tyrosine Kinase Proteins Proteomics Protocols documentation Recombinant Antibody Role Serum Signal Pathway Signal Transduction Small Interfering RNA Staging Testing Therapeutic Time Tyrosine Phosphorylation base clinically significant cytokine disorder control glycosylation in vivo in vivo Model inhibitor/antagonist innovation insight kidney cell kinase inhibitor knock-down mesangial cell molecular mass mouse model new therapeutic target non-invasive monitor novel novel therapeutics outcome forecast patient subsets prevent profilin protein kinase inhibitor receptor research study response small molecule inhibitor therapeutic target

项目摘要

DESCRIPTION (provided by applicant): IgA nephropathy (IgAN) is the most common primary glomerulonephritis and an important cause of end-stage kidney failure. It is a mesangioproliferative glomerulonephritis defined by IgA1 mesangial deposits. Although it has been speculated for some time that the pathogenesis of IgAN is driven by deposition of circulating immune complexes (IC), this has been difficult to prove due to the lack of animal models of IgAN. Our development of new protocols that permit formation of engineered IC in vitro and establishment of a passive mouse model of IgAN provide an unprecedented opportunity to elucidate the pathophysiology of IgAN and identify potential therapeutic targets. In IgAN, a fraction of circulating IgA1 has galactose-deficient O-glycans (Gd-IgA1) and is present in circulating IC bound by glycan-specific autoantibodies. We now have characterized Gd-IgA1 and the anti-Gd-IgA1 autoantibodies that are present in these IC and used targeted proteomic approaches to both define the serum factors that associate with these IC and may contribute to their pathogenic effects and to identify the mesangial-cell receptors for the ICs. Rational extension of these studies required analysis of the molecular effects of these pathogenic IgAN ICs on the signaling events that lead to mesangial-cell activation. Global kinase-activity profilin using an innovative peptide substrate microarray platform of human mesangial cells stimulated with Gd-IgA1 IC identified robust tyrosine kinase activity as a major player in IC-induced signaling in three predominant pathways. Similar results were obtained with native and engineered ICs. The mesangial-cell responses after stimulation with these IC were typical of IgAN but differed from those obtained by using IC lacking all of the components in pathogenic ICs. An association with pathogenesis was demonstrated using protein-kinase inhibitors, which confirmed that one of the inhibitors completely blocked IC- mediated mesangial cell proliferation in vitro as well as in vivo in the passive mouse model of IgAN. These data suggest the hypothesis that Gd-IgA1-containing ICs represent a key hit in the pathogenesis of IgAN by activating mesangial cells through specific signaling pathways; the corollary is that this IC-drive signaling in mesangial cells can be blocked by small-molecular-mass inhibitors of protein kinases and thus represents a feasible therapeutic target(s). The team of basic and clinical investigators that has developed the powerful proteomic, kinomic, and cellular approaches used to generate the preliminary data will now test this hypothesis by: 1) Defining the characteristics of Gd-IgA1-containing ICs from sera of patients with IgAN that activate human mesangial cells; 2) Characterizing the signaling pathways activated by Gd-IgA1-containing ICs in mesangial cells; and 3) Determining the efficacy of small-molecular-mass inhibitors of key protein kinases on mesangial cell activation in vivo using the animal model of IgAN. Relevance: The results will shed light on the pathogenesis of IgAN and identify therapeutic targets for disease-specific treatment of IgAN as well as potential response/prognostic biomarkers.

描述（由申请人提供）：IgA肾病（IGAN）是最常见的原发性肾小球肾炎，也是终末期肾脏衰竭的重要原因。它是由IGA1肾小球膜定义的肾小球增生性肾小球肾炎。尽管已经推测一段时间以来，Igan的发病机理是由循环免疫复合物（IC）的沉积驱动的，但由于缺乏Igan动物模型，这很难证明这是很难证明的。我们开发了允许在体外形成工程IC的新方案，并建立了Igan的被动小鼠模型，这为阐明Igan的病理生理并识别潜在的治疗靶标提供了前所未有的机会。在 Igan（循环IgA1）的一部分具有半乳糖缺陷的O-聚糖（GD-IGA1），并且存在于受聚糖特异性自身抗体绑定的循环IC中。现在，我们已经表征了GD-IGA1和抗GD-IGA1自身抗体，这些自身抗体存在于这些IC中，并使用了靶向蛋白质组学方法，可以定义与这些IC相关的血清因子，并可能有助于其病原效应并确定ICS的中臂细胞受体。这些研究的合理扩展需要分析这些致病性Igan IC对导致肾小球细胞激活的信号传导事件的分子效应。使用GD-IGA1 IC刺激的人膜细胞的创新肽底物微阵列平台使用创新的肽底物微阵列平台的全球激酶活性蛋白酶刺激了稳健的酪氨酸激酶活性是三个主要途径中IC诱导信号传导的主要参与者。用天然和工程ICS获得了类似的结果。用这些IC刺激后的膜细胞反应是Igan的典型代表，但与使用缺乏致病性IC中所有组件获得的IC所获得的响应不同。使用蛋白激酶抑制剂证明了与发病机理的关联，该抑制剂证实了其中一种抑制剂在体外完全阻断了IC介导的介导的介导的细胞增殖以及在Igan的被动小鼠模型中的体内。这些数据表明，含GD-IgA1的ICS通过特定的信号通路激活肾小球细胞来代表IGAN的发病机理中的关键打击。推论的是，这种蛋白激酶的小分子质量抑制剂可以阻断中膜细胞中的IC驱动信号，因此代表了可行的治疗靶标（S）。基本和临床研究者的团队开发了用于生成初步数据的强大蛋白质组学，活性和细胞方法，现在将通过：1）定义来自Igan患者的含GD-IGA1的IC的特征来检验此假设，从而激活人类的细胞。 2）表征在膜细胞中含有GD-IGA1的IC激活的信号传导途径； 3）使用IGAN动物模型，确定关键蛋白激酶小分子质量抑制剂在体内膜细胞激活中的疗效。相关性：结果将阐明IGAN的发病机理，并确定用于特异性治疗IGAN以及潜在反应/预后生物标志物的治疗靶标。