IgA-secreting B cell lines: a novel tool for studies of IgA nephropathy

描述（由申请人提供）：（IgAN）的特征在于系膜IgA 1免疫沉积。这些沉积物来源于含有异常糖基化的IgA 1的循环免疫复合物，即，铰链区O-连接聚糖中半乳糖缺陷的IgA 1。一些证据表明异常糖基化，形成含有异常糖基化的IgA 1的免疫复合物，它们在系膜中的沉积和IgAN的肾损伤之间存在直接的因果关系。这些数据提供了基础的核心假设，O-糖基化异常的铰链区的IgA 1是一个关键的致病特征的IgA肾病。然而，由于目前无法获得足够的致病性异常糖基化IgA 1的信息样本用于分子分析，将这些观察结果转化为临床相关的非侵入性诊断测试和新疗法的能力受到了挫折。我们假设，永生化的IgA 1生产细胞系IgAN患者可以用于分析O-糖基化异常和特定的代谢机制，导致这种缺陷。本研究的目的是从IgAN患者和对照组的循环B细胞中建立分泌IgA 1的永生化细胞系，并评估这种新工具用于推进IgAN发病机制研究的潜力。具体而言，我们建议确定的精细结构的O-糖基化异常的铰链区的IgA 1分泌的永生化细胞从IgA肾病患者，并确定酶的途径，可能导致这种缺陷。这些研究的可行性大大提高了我们的高通量分析方法的发展，国家的最先进的糖肽分析技术，以及我们广泛的基础和临床合作，允许通过实验操作以及临床相关性的假设测试。相关性：IgAN是最常见的原发性肾小球肾炎，导致20-40%的患者肾功能丧失。目前无法在分子水平上描述IgA AN的发病机制是IgA特异性治疗发展的主要障碍。拟议的研究将为IgAN发病机制的分子机制研究提供一个重要的新工具，并为未来开发和测试潜在的新治疗干预措施提供一个关键资源。这将代表IgAN患者护理质量的重大进步。IgAN是最常见的原发性肾小球肾炎。其特征在于异常糖基化的IgA 1，其代表关键的致病特征。从IgAN患者的细胞系的拟议开发将提供一个重要的新工具，用于识别IgA 1异常糖基化的IgAN患者的缺陷，从而奠定了基础研究转化为临床应用的基础。

DESCRIPTION (provided by applicant): (IgAN) is characterized by mesangial IgA1 immune deposits. These deposits originate from circulating immune complexes that contain aberrantly-glycosylated IgA1, i.e., IgA1 that is galactose-deficient in the hinge region O-linked glycans. Several lines of evidence suggest a direct causal relationship between aberrant glycosylation, the formation of immune complexes containing aberrantly glycosylated IgA1, their deposition in the mesangium, and renal injury in IgAN. These data provide the basis for the central hypothesis that an O- glycosylation abnormality in the hinge region of IgA1 is a pivotal pathogenic feature of IgAN. The ability to translate these observations into clinically relevant non-invasive diagnostic tests and novel therapeutics has been frustrated, however, by the current inability to obtain sufficient, informative samples of the pathogenic aberrantly glycosylated IgA1 for molecular analysis. We hypothesize that immortalized IgA1-producing cell lines from patients with IgAN can be used for analysis of the O-glycosylation abnormality and the specific metabolic mechanisms that result in this defect. The goal of the proposed study is to establish immortalized IgA1-secreting cell lines from circulating B cells from patients with IgAN and controls and to evaluate the potential of this new tool for advancing the studies of IgAN pathogenesis. Specifically, we propose to determine the fine structure of the O-glycosylation abnormalities of the hinge region of IgA1 secreted by the immortalized cells from IgAN patients and to identify the enzymatic pathways that may lead to this defect. The feasibility of these studies is enhanced greatly by our development of high throughput methods of analysis, state-of-the-art techniques for analysis of glycopeptides, and our extensive basic and clinical collaborations that permit testing of the hypothesis by experimental manipulation as well as clinical correlations. Relevance: IgAN is the most common primary glomerulonephritis and leads to the loss of renal function in 20-40% patients. The current inability to describe the pathogenesis of IgAN at the molecular level is a major barrier to the development of IgA-specific treatments. The proposed studies will provide an essential new tool for studies of the molecular mechanisms of pathogenesis of IgAN and a key resource for the future development and testing of potential new therapeutic interventions. This would represent a major advance in the quality of care for IgAN patients. IgAN is the most common primary glomerulonephritis. It is characterized by aberrantly- glycosylated IgA1, which represents a pivotal pathogenic feature. The proposed development of cell lines from IgAN patients will provide a significant new tool for the identification of the defects underlying the abnormal glycosylation of IgA1 in patients with IgAN and, thus, lay the basis for the translation of the basic research into clinical applications.