NADPH-Oxidase and SLE Susceptibility

描述(申请人提供)：系统性红斑狼疮(SLE或狼疮)是一种复杂的，多器官的，临床异质性的，具有潜在致命性的自身免疫性疾病，具有大量的遗传和环境因素。在美国，SLE影响了大约200万人，其中大部分是女性(~90%)，非洲人、亚洲人和西班牙人血统的患病率是欧洲血统的3-5倍。尽管系统性红斑狼疮对公众健康具有重要意义，但其发病机制尚不清楚。感染是导致发病率和死亡率的主要原因，占系统性红斑狼疮患者死亡的25%。活性氧(ROS)，如超氧化物和过氧化氢，是抵御入侵的微生物病原体的关键，并在吞噬过程中由多蛋白NADPH-氧化酶(NADPHO)系统产生。这个多蛋白复合体由7个必需基因编码：NCF1、NCF2、NCF4、Cyba、CyBB、rac1或rac2。尽管NADPHO在系统性红斑狼疮的病理生理学中可能很重要，但到目前为止，7项全基因组相关性研究中没有一项检测到系统性红斑狼疮相关性。利用大型多种族队列(来自欧洲裔美国人(EA)、非裔美国人(AA)、西班牙裔美国人(HS)和韩国人(KR)的N&GT；17,000人)，我们在NCF2中确定了至少7个独立的和潜在功能的SLE易感性变异(10-44；P&lt；10-7)。我们也有提示证据(10-4和lt；p&lt；10-2)，来自编码NADPHO其他亚单位的基因的多个变异，暗示其在SLE易感性中的因果作用。我们确定了民族强健和种族特定的系统性红斑狼疮易感变异。此外，我们的数据表明，NADPHO基因的变异可能会影响SLE的临床亚型；即，在EA中，rs17849502错义与狼疮性肾炎(OR=3.5)和男性SLE(OR=4.23)的相关性比一般SLE(OR=2.5)更强。对选定变种的后续生物信息学和分子模拟分析显示，脊椎动物之间高度保守，暗示了潜在的功能作用，并预测了最终扰乱ROS产生的NADPHO组装的有害影响。我们假设，使用来自4个不同种族群体的个体进行密集基因分型，结合条件分析和分子建模，将识别出多个潜在的功能变异(罕见和常见)，这两个种族都是如此 在NADPHO基因中，强健和特定于种族。我们提出了三个具体的目标：(1)识别和精确定位编码NADPHO复合体的基因中的易患SLE的变异，(2)阐明导致SLE临床异质性的遗传变异，(3)结合分子模拟来预测易患SLE的功能变异的机制效应。凭借我们的初步发现、研究策略、可用的生物材料、资源、基础设施，以及我们研究团队的经验、专业知识和跟踪记录，我们有极大的潜力成功完成拟议的项目。最终，一组新的功能变体将提供给科学界，并为未来的生物学实验提供基础，以确定NADPHO如何参与狼疮的病理机制。

DESCRIPTION (provided by applicant): Systemic lupus erythematosus (SLE or lupus) is a complex, multi-organ, clinically heterogeneous, potentially fatal autoimmune disease with substantial genetic and environmental components. In U.S., SLE affects ~2 million people, mostly women (~90%), and prevalence is >3-5 times higher in individuals of African, Asian and Hispanic ancestries compared to European ancestry. Despite its public health importance, SLE pathogenesis is not well understood. Infection is a leading cause of morbidity and mortality, accounting for >25% of deaths in SLE patients. Reactive oxygen species (ROS), such as superoxide and hydrogen peroxide are key for defense against invading microbial pathogens, and are produced by the multi-protein NADPH- oxidase (NADPHO) system during phagocytosis. This multi-protein complex is encoded by 7 essential genes: NCF1, NCF2, NCF4, CYBA,CYBB, Rac1 or Rac2. Although NADPHO is likely to be important in SLE pathophysiology, thus far, none of the 7 genome-wide association studies detected SLE association. Using large multi-ethnic cohorts (N > 17,000 from European-Americans (EA), African-Americans (AA), Hispanics (HS), and Koreans (KR)), we have identified at least 7 independent and potentially functional SLE-susceptibility variants (10-44<p<10-7) within NCF2. We also have suggestive evidence (10-4<p<10-2) of multiple variants from genes encoding the other subunits of NADPHO, implicating its causal role in SLE susceptibility. We identified both ethnically-robust and ethnicity-specific SLE predisposing variants. Moreover, our data suggest that variation in NADPHO may influence SLE clinical sub-phenotypes; i.e., in EA, missense rs17849502 is more strongly associated with lupus nephritis (odds ratio (OR) = 3.5), and with SLE in males (OR = 4.23), compared to SLE in general (OR = 2.5). Follow up bioinformatic and molecular modeling analyses on selected variants show high conservation across vertebrates, implicating potential functional roles and predicting detrimental effects on NADPHO assembly that ultimately disrupt ROS production. We hypothesize that dense genotyping using individuals from 4 ethnically diverse populations, combined with conditional analysis and molecular modeling, will identify multiple potentially functional variants (rare and common), both ethnically robust and ethnicity-specific, within NADPHO genes. We propose three Specific Aims: (1) Identify and pinpoint SLE- predisposing variants within genes encoding the NADPHO complex, (2) Elucidate genetic variants contributing to the clinical heterogeneity of SLE, (3) Use these in conjunction with molecular modeling to predict mechanistic effects of SLE-predisposing functional variants. With our preliminary findings, research strategies, available biomaterials, resources, infrastructure, and experience, expertise and track records of our research team, we have excellent potential to successfully complete the proposed project. Ultimately, a set of novel functional variants will be made available to the scientific community and provide a basis for future biological experiments to define how NADPHO contributes to the pathological mechanisms of lupus.