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，使人衰弱的自身免疫性疾病，其特征在于 广泛的炎症和自身抗体的大量产生。遗传学无疑有助于 SLE的病因学，统计学上稳健的关联研究建立了83个独立的SLE遗传风险位点。 然而，有效的诊断，治疗和预防系统性红斑狼疮是阻碍了缺乏明确的机制见解 这些基因位点的生物学意义。83个独立的SLE风险基因座中有21个编码 约90%的SLE风险基因座仅含有非编码变异。因此，基因调控 可能是SLE遗传病因学的关键方面。因此，我们的目标是确定的机械贡献， 转录因子与SLE的关系在我们的建议中，我们评估风险的直接下游生物影响， 改变转录因子（IRF 7- Aim 1）氨基酸序列的变异，改变转录因子（IRF 7- Aim 1）氨基酸序列的多种风险变异， 第二个转录因子（SPI 1/PU.1 - Aim 2）的基因组结合位点，并检查协同控制 这两种蛋白质的基因表达（目的3）。我们还使用创新的新小鼠品系和实验 狼疮模型，以探讨这两种因素在疾病发病机制中的作用（目的3）。 在目的1中，我们奋进确定为什么干扰素调节因子-7（IRF 7）412位基因型 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IRF 7抑制剂作为新疗法的重要依据。 SLE。在目标2中，我们的发现是转录因子SPI 1/PU.1在SLE风险位点或附近结合， 在包括自然杀伤（NK）细胞在内的许多细胞类型中，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发生改变，导致 SLE患者NK细胞中的靶基因。在目标3中，我们使用具有SLE风险的创新小鼠品系- 相关的IRF 7变异或NK细胞限制性PU.1缺陷，以确定这些致病作用 转录因子在狼疮发展中的作用我们还研究了PU.1和IRF 7的分子相互作用， NK细胞基因组中的复合DNA结合元件，其中这两种因子可以协同结合， 调节基因表达，促进疾病。我们的提案利用协作、概念和 方法创新，以便在理解独立和 两种不同转录因子与SLE交叉的潜在组合分子机制 危险基因座来促进疾病。

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.