Transcription Factor Genetics in Lupus

摘要 系统性红斑狼疮(SLE或狼疮)是一种无法治愈的、衰弱的自身免疫性疾病 由于广泛的炎症和猖獗的自身抗体的产生。遗传学无疑对人类的 SLE的病因学，统计上可靠的关联研究建立了83个独立的SLE遗传风险基因座。 然而，系统性红斑狼疮的有效诊断、治疗和预防由于缺乏明确的机械性见解而受到阻碍。 这些基因座的生物学意义。83个独立的系统性红斑狼疮风险基因座中的21个编码 转录因子，约90%的系统性红斑狼疮风险基因座只包含非编码的变体。因此，基因调控 可能是系统性红斑狼疮遗传病因学的一个关键方面。因此，我们的目标是确定 转录因子到系统性红斑狼疮。在我们的提案中，我们评估了风险对下游生物的直接影响 改变转录因子的氨基酸序列的变异(IRF7-AIM 1)，多个风险变异 第二个转录因子(SPI1/PU.1-AIM 2)的基因组结合位点，并检查合作对照 这两种蛋白的基因表达(目标3)。我们还使用了创新的新小鼠品系和实验 建立狼疮模型，探讨这两个因素在疾病发病机制中的作用(目标3)。 在目标1中，我们努力确定为什么干扰素调节因子-7(IRF7)412位的基因型 改变细胞对细胞内信号的功能反应，包括来自Toll样受体的信号。这些 这些数据将是开发Q412特异性IRF7抑制剂作为新的治疗药物的重要理论基础。 SLE。在目标2中，我们建立在我们的发现的基础上，转录因子SPI1/PU.1很大程度上结合在SLE风险区域或附近 在许多细胞类型中，包括自然杀伤(NK)细胞，都比预期的要高。全球最新数据 将NK细胞功能障碍与狼疮风险联系起来，并支持NK细胞代表重要的新的 治疗干预的目标。我们利用我们的NK细胞专业知识和这些令人兴奋的新数据来测试 假设PU.1结合在多个狼疮遗传风险位点处发生改变，导致PU.1基因异常表达 系统性红斑狼疮患者NK细胞靶基因的研究在目标3中，我们使用了具有系统性红斑狼疮风险的创新小鼠品系- IRF7的相关变异或PU.1的NK细胞限制性缺陷以确定它们的致病作用 转录因子在狼疮发病中的作用。我们还研究了PU.1和IRF7的分子相互作用 NK细胞基因组中的复合DNA结合元件，这两种因子可能协同结合， 调节基因表达，促进疾病发生。我们的建议利用协作、概念性和 方法创新，以取得有意义的进展，朝着理解独立和 两种不同转录因子与系统性红斑狼疮相互作用的潜在组合分子机制 风险基因促进疾病的发生。

ABSTRACT Systemic Lupus Erythematosus (SLE or lupus) is an incurable, debilitating autoimmune disease characterized by widespread inflammation and rampant production of autoantibodies. Genetics undoubtedly contributes to the etiology of SLE, with statistically robust association studies establishing 83 independent SLE genetic risk loci. Yet, effective diagnosis, treatment, and prevention of SLE is hindered by a dearth of clear mechanistic insights into the biological significance of these genetic loci. Twenty-one of 83 independent SLE risk loci encode transcription factors, and ~90% of SLE risk loci only contain variants that are non-coding. Thus, gene regulation is a likely critical aspect of SLE genetic etiology. We therefore aim to determine the mechanistic contributions of transcription factors to SLE. In our proposal, we assess the immediate downstream biological impact of risk variants that alter the amino acid sequence of a transcription factor (IRF7 - Aim 1), multiple risk variants that alter the genomic binding sites of a second transcription factor (SPI1/PU.1 - Aim 2), and examine cooperative control of gene expression by these two proteins (Aim 3). We also use innovative new mouse strains and experimental lupus models to explore the role of both factors in disease pathogenesis (Aim 3). In Aim 1, we endeavor to identify why the genotype at position 412 in interferon regulatory factor-7 (IRF7) changes the functional response of cells to intracellular signals, including those from toll-like receptors. These data will be important rationale for the development of Q412-specific inhibitors of IRF7 as novel therapeutics in SLE. In Aim 2, we build on our finding that the transcription factor SPI1/PU.1 binds at or near SLE risk loci much more than expected by chance in numerous cell types, including natural killer (NK) cells. Recent data globally link NK cell dysfunction to lupus risk, and support the burgeoning view that NK cells represent important new targets for therapeutic interventions. We leverage our NK cell expertise and these exciting new data to test the hypothesis that PU.1 binding is altered at multiple lupus genetic risk loci, leading to dysregulated expression of target genes in NK cells from SLE patients. In Aim 3, we use innovative mouse strains harboring an SLE risk- associated variant of IRF7 or NK-cell-restricted deficiency of PU.1 to determine the pathogenic roles of these transcription factors in the development of lupus. We also examine molecular interaction of PU.1 and IRF7 at composite DNA binding elements in the genome of NK cells, where these two factors may cooperatively bind, regulate gene expression, and promote disease. Our proposal leverages collaborative, conceptual, and methodological innovation to make meaningful progress towards the understanding of the independent and potentially combinatorial molecular mechanisms by which two different transcription factors intersect with SLE risk loci to promote disease.