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

描述（由申请人提供）：（IgAN）以系膜IgA1免疫沉积为特征。这些沉积源于循环免疫复合物，其中含有异常糖基化的IgA1，即IgA1在铰链区o链聚糖中缺乏半乳糖。一些证据表明，在异常糖基化、含有异常糖基化IgA1的免疫复合物的形成、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。这些数据为IgA1铰链区的O-糖基化异常是IgAN的关键致病特征这一中心假设提供了基础。然而，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治疗方法的能力一直受到挫折，因为目前无法获得足够的致病异常糖基化IgA1的信息样本进行分子分析。我们假设来自IgAN患者的永生化iga1产生细胞系可以用于分析o糖基化异常和导致这种缺陷的特定代谢机制。该研究的目的是利用IgAN患者和对照组的循环B细胞建立永生化的iga1分泌细胞系，并评估这种新工具在推进IgAN发病机制研究方面的潜力。具体来说，我们建议确定IgAN患者的永生化细胞分泌的IgA1铰链区o -糖基化异常的精细结构，并确定可能导致这种缺陷的酶途径。这些研究的可行性大大增强了我们开发的高通量分析方法，最先进的糖肽分析技术，以及我们广泛的基础和临床合作，允许通过实验操作和临床相关性来测试假设。相关性：IgAN是最常见的原发性肾小球肾炎，可导致20-40%患者肾功能丧失。目前无法在分子水平上描述IgAN的发病机制是开发iga特异性治疗的主要障碍。这些研究将为研究IgAN的分子机制提供重要的新工具，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。它的特点是异常糖基化的IgA1，这是一个关键的致病特征。提出的IgAN患者细胞系的开发将为鉴定IgAN患者中IgA1异常糖基化的缺陷提供重要的新工具，从而为基础研究转化为临床应用奠定基础。

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.