OK COBRE: GENETICS OF B LYMPHOCYTE SIGNALING IN LUPUS

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 系统性红斑狼疮(SLE)是一种临床症状多样的复杂、多基因自身免疫性疾病。寻找与疾病相关的基因已经利用了许多互补的方法；然而，我们仍然没有完全了解SLE相关候选基因实际上是如何导致人类疾病的生物学原理。生物体、免疫系统和环境的复杂性影响了我们专注于基因组中编码的分子细节的能力，这些细节影响到对疾病发展至关重要的蛋白质的生物结构和功能。 B细胞现在被认为是SLE发展过程中的中心角色。自身抗体的产生需要B细胞的激活，而自身抗体是SLE相关病理发展的关键。我们怀疑，由B细胞表面受体参与引起的影响控制B细胞信号的关键蛋白质的基因表达或功能的遗传多态是狼疮患者观察到的B细胞反应改变的原因。 我们识别这些基因和多态的方法要求我们首先定义系统的边界(B细胞的激活和控制)，可测量的影响(生物分子表型)，并收集感兴趣人群的表型数据。下一步将分析第一阶段的表型数据和通过数量性状关联分析独立收集的祖先信息遗传标记的遗传数据。第三阶段是确定导致B细胞反应表型改变的遗传变异，并确定受影响的生物分子途径和机制。 我们使用来自非裔美国人(AA)狼疮患者和对照的EBV转化细胞系来确定B细胞信号通路的关键组成部分如何响应B细胞受体(BCR)的交联。我们已经证实，狼疮患者和对照组的细胞也表现出改变的B细胞反应谱。在这些细胞系中，细胞内钙反应、ERK1/2磷酸化和Lyn对B细胞特异性信号的磷酸化都发生了改变。狼疮患者和对照组细胞系之间的基因表达是不同的，并已确定了一组基因/蛋白质，这些基因/蛋白可能参与导致B细胞反应的差异。我们开始确定表征狼疮B细胞反应的关键分子表型。我们现在将重点放在这些途径的组成部分上，因为我们扩大了我们对来自AA狼疮病例和对照的额外B细胞系的这些分子表型的测量和分析。我们正在检查在初步基因表达分析中确定的单个候选基因，确认它们的表达，探索可能的多态，并测试这些基因与狼疮的独立遗传关联。我们很好地描述了在选定的狼疮患者亚群中观察到的B细胞反应的候选功能差异，并建立了结合B细胞系统中的生物分子亚型来利用定量遗传分析的能力。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Systemic lupus erythematosus (SLE) is a complex, multigenic autoimmune disease with diverse clinical symptoms. The search for the genes associated with the disease has utilized numerous complementary approachs; however, we still do not have a complete understanding of the biology behind how SLE-associated candidate genes actually cause the human disease. The complexity of the organism, the immune system and the environmental influences cloud our ability to focus on the molecular details encoded in the genome that affect the biological structures and functions in proteins important to the development of disease. B cells are now recognized as central players in the development of SLE. B cell activation is required for development of autoantibodies, which are key to the development of SLE associated pathology. We suspect genetic polymorphisms that affect the gene expression or function of proteins critical in controlling B cell signaling resulting from B cell surface receptor engagement are responsible for altered B cell responses observed in lupus patients. Our approach to identify these genes and polymorphisms requires that we first define the boundaries of the system (B cell activation and control), the measurable effects (biomolecular phenotypes) and collect phenotypic data on the population of interest. The next step would be to analyze the combined phenotypic data from phase 1 and independently collected genetic data on ancestral informative genetic markers by Quantitative Trait Association analysis. Phase 3 is to identify genetic variants responsible for altered B cell response phenotypes and determine the biomolecular pathways and mechanisms affected. We have used EBV-transformed cell lines derived from African-American (AA) lupus patients and controls to identify how key components of the B cell signaling pathways respond to B cell receptor (BCR) cross-linking. We have confirmed that cells from lupus patients and controls also exhibit altered B cell response profiles. Intracellular calcium responses, ERK1/2 phosphorylation, and Lyn phosphorylation upon B cell specific signaling are altered in these cell lines. Gene expression between cell lines from lupus patients and controls is different and has identified a set of genes/proteins which are likely involved in causing differences in B cell responses. We are beginning to identify key molecular phenotypes that characterize a lupus B cell response. We will now focus on components of those pathways as we expand our measurement and analysis of these molecular phenotypes in additional B cell lines from AA lupus cases and controls. We are examining individual candidate genes identified in the preliminary gene expression analysis, confirming their expression, exploring possible polymorphisms, and testing these for independent genetic association with lupus. We are well positioned to describe candidate functional differences in B cell responses observed in selected subsets of lupus patients and also to build the ability to exploit the power of quantitative genetic analysis in combination with biomolecular sub-phenotypes in the B cell system.