Impact of Loss-of-function NADPH Oxidase Variants on B cell Activation in SLE

项目摘要 全基因组关联研究已经确定了与霍乱发病相关的免疫途径。 系统性红斑狼疮(SLE)。然而，尽管有这些见解，我们对个人如何 促进自身免疫的基因变异仍然很少。吞噬细胞基因功能丧失突变 NADPH氧化酶复合体(NOX2)包括NCF1和NCF2，与SLE的发病机制有关 以及其他体液自身免疫性疾病。NOX2活性减少如何促进狼疮的当前模型 研究的重点是吞噬髓系对凋亡物质清除的缺陷。而当 髓系缺陷可能导致疾病风险，我们假设一种平行的B细胞内在机制 在携带NCF1和NCF2变异体的人类中，SLE的风险显著增加。除 产生致病性自身抗体，最近的研究表明B细胞可以促进狼疮 启动免疫耐受破坏和促进自发生发的发病机制 中心(GC)。系统性红斑狼疮自身反应性B细胞的激活需要B细胞内分泌表达 Toll样受体TLR7和TLR9，以及我们已发表的和初步的数据显示，NOX2活性降低 通过影响非规范的自噬途径，导致内体TLR信号的失调。基于 这些数据，我们假设，B细胞特异性的NOX2活性的降低将导致TLR- 依赖型GC的形成与体液自身免疫的发展。我们将通过体内平行试验来检验这一想法 以及体外机制研究。在目标1中，我们将测试B细胞内在缺失NOX2组分基因 结果增强了依赖TLR的GC反应，使用了一个具有良好特征的病毒感染模型。在目标2中， 我们将研究NOX2活性降低是否促进自身抗体的产生和体液自身免疫 小鼠系统性红斑狼疮。最后，在目标3中，我们将使用生化和细胞成像方法来测试NAPDH是否 氧化酶活性影响B细胞TLR信号转导和非典型自噬途径 模型和基因编辑的人类B细胞。总之，这些研究有望促进我们对狼疮的理解。 并可能为未来人类系统性红斑狼疮靶向治疗的设计提供参考。

Project abstract Genome-wide association studies (GWAS) have identified immune pathways linked to the pathogenesis of systemic lupus erythematosus (SLE). However, despite these insights, our understanding of how individual genetic variants promote autoimmunity remains poor. Loss-of-function mutations in genes of the phagocytic NADPH oxidase complex (NOX2), including NCF1 and NCF2, have been linked with the pathogenesis of SLE and other humoral autoimmune diseases. The current model for how reduced NOX2 activity promotes lupus development focuses on defects in the clearance of apoptotic material by phagocytic myeloid lineages. While myeloid defects likely contribute to disease risk, we hypothesize that a parallel B cell-intrinsic mechanism underlies the profound increase risk of SLE in human carriers of NCF1 and NCF2 variants. In addition to the production of pathogenic autoantibodies, recent studies have demonstrated that B cells can promote lupus pathogenesis by initiating immune tolerance breaks and facilitating the generation of spontaneous germinal centers (GC). The activation of autoreactive B cells in SLE requires B cell-intrinsic expression of the endosomal toll-like receptors TLR7 and TLR9, and our published and preliminary data show that reduced NOX2 activity results in dysregulated endosomal TLR signaling by impacting non-canonical autophagy pathways. Based on these data, we hypothesize that a B cell-specific reduction in NOX2 activity will result in enhanced TLR- dependent GC formation and the development of humoral autoimmunity. We will test this idea via parallel in vivo and in vitro mechanistic studies. In Aim 1, we will test whether B cell-intrinsic deletion NOX2 component genes results in enhanced TLR-dependent GC responses using a well-characterized model of viral infection. In Aim 2, we will study whether reduced NOX2 activity promotes autoantibody production and humoral autoimmunity in murine SLE. Finally, in Aim 3, we will use biochemical and cell imaging approaches to test whether NAPDH oxidase activity impacts B cell TLR signaling and non-canonical autophagy pathways using both murine genetic models and gene-edited human B cells. Together, these studies promise to advance our understanding of lupus pathogenesis and may inform the design of future targeted therapies for human SLE.