Role of Two Interferon Regulatory Genes in Lupus

两个干扰素调节基因在狼疮中的作用

基本信息

批准号：
10115587
负责人：
Swapan K. Nath
金额：
$ 26.22万
依托单位：
OKLAHOMA MEDICAL RESEARCH FOUNDATION
依托单位国家：
美国
项目类别：
财政年份：
2020
资助国家：
美国
起止时间：
2020-03-01 至 2023-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10115587
关键词：
African American Alleles American Antigen-Antibody Complex Asian Americans Asians Autoantibodies Autoimmune Diseases Autoimmunity Base Sequence Binding Bioinformatics Blood Blood Cells Candidate Disease Gene Caucasians Cell Line Cells Chromatin Clinical Complex Cultured Cells Data Dendritic Cells Deposition Development Diagnosis Disease Drug Targeting Epigenetic Process Ethnic Origin European Family Frequencies Future Gene Expression Genes Genetic Genetic Heterogeneity Genotype Goals Haplotypes Heritability Hispanics Histidine Host Defense Human Hyperactivity Immune Immune response Immune system In Vitro Incidence Individual Infection Inflammation Inflammatory Interferon Type I Interferon Type II Interferon-alpha Interferons Interleukin-12 Kidney Knock-out Lead Link Linkage Disequilibrium Luciferases Lupus Lupus Nephritis Malignant Neoplasms Mediating Molecular Mus Mutation Organ Pathogenesis Pathogenicity Pathway interactions Patients Phenotype Plant Roots Play Population Population Heterogeneity Predisposition Prevention strategy Production Records Regulator Genes Reporting Research Resources Risk Risk Factors Role Running Sampling Serum Spleen Structure System Systemic Lupus Erythematosus Tissues Validation Variant Woman base causal variant clinical heterogeneity cytokine early onset ethnic disparity ethnic diversity experimental study genetic association genetic signature genetic variant genome wide association study insight lymph nodes macrophage men monocyte mouse model mutant new therapeutic target novel novel therapeutics pathogenic autoantibodies peripheral lymphoid organ prototype risk variant solute therapeutic target

项目摘要

ABSTRACT Systemic lupus erythematosus (SLE or lupus) is a prototype of type-I interferon (IFN-I)-mediated autoimmune disease, characterized by a myriad of clinical manifestations including inflammation, pathogenic autoantibody production, and irreversible end-organ damage (e.g. kidneys). SLE disproportionately afflicts women (nine-fold higher than men) and non-white ethnicities. Asians and African-Americans have higher SLE incidence, more severe disease manifestations, and greater risk of organ damage (e.g. lupus nephritis) than Caucasians. Others and we have reported that several IFN regulatory genes, including IFN regulatory factor 8 (IRF8), and solute carrier family 15 number 4 (SLC15A4) are involved in SLE susceptibility. IFNs are a family of cytokines with important roles in infection, cancer, and autoimmunity. In vitro evidence suggests that plasmacytoid dendritic cells (pDCs), the principal IFN-I producing immune cells, are intimately involved in SLE development. A recent study using two mouse models (Irf8-/- knockout and Slc15a4 mutant) provided direct evidence that pDCs contribute to SLE via hyper-production of IFN-I. Thus, IRF8 and SLC15A4 could potentially be involved in human SLE progression. Our genetic association data identified several potential SLE predisposing variants for IRF8 (best p=1.2x10-22) and for SLC15A4 (best p=1.5x10-21) across multiple ethnicities. However, despite strong association, specific pathogenic variants and their underlying molecular mechanisms are not yet defined. Using bioinformatics, we predicted that several associated variants are cis-eQTLs, with roles in regulating gene expression. Using luciferase and ChIP-qPCR, we experimentally validated allele-specific effects of several predicted functional variants. Since IFN gene signatures are a prominent feature in SLE, we hypothesize that comprehensive, trans-ethnic mapping (TEM) followed by experimental validation with functional genetics, including genetic and epigenetic editing in relevant immune cells, will identify causal variants and their functional consequences in IFN-I production. Our research team has the expertise, resources, and track records to discover and characterize functional variants for SLE. In Aim 1, we will localize SLE-predisposing variants from these genes by performing comprehensive imputation-based TEM across ethnically diverse populations (N>30,000 from Asians, African-Americans, European-Americans, Egyptians, and Hispanics). Promising variants, especially imputed and low-frequency variants, will be validated through additional confirmatory genotyping. We will elucidate genetic and clinical heterogeneity by assessing associations with clinical sub-phenotypes and autoantibodies. In Aim 2, we will experimentally validate functional relevance of putative variants as regulators of gene expression and IFN-I production. We will use both cultured cells (THP-1) and primary immune cells (pDCs, monocytes) from SLE patients and controls. Insights gained from this project will help to define the molecular mechanisms underlying how risk alleles predispose to SLE, and may define novel drug/therapeutic targets for SLE in the future.

抽象的系统性红斑狼疮（SLE 或狼疮）是 I 型干扰素 (IFN-I) 介导的自身免疫性疾病的原型疾病，以多种临床表现为特征，包括炎症、致病性自身抗体生产和不可逆的终末器官损伤（例如肾脏）。系统性红斑狼疮 (SLE) 严重影响女性（是女性的九倍）高于男性）和非白人种族。亚洲人和非裔美国人的 SLE 发病率更高，与白种人相比，疾病表现更严重，器官损伤（例如狼疮性肾炎）的风险更大。其他的我们已经报道了一些干扰素调节基因，包括干扰素调节因子8（IRF8）和溶质携带者家族 15 号 4 (SLC15A4) 与 SLE 易感性有关。干扰素是一个细胞因子家族在感染、癌症和自身免疫中发挥重要作用。体外证据表明浆细胞样树突细胞 (pDC) 是产生 IFN-I 的主要免疫细胞，与 SLE 的发展密切相关。最近的一个使用两种小鼠模型（Irf8-/- 敲除型和 Slc15a4 突变型）的研究提供了 pDCs 的直接证据通过 IFN-I 的过度产生而导致 SLE。因此，IRF8 和 SLC15A4 可能参与人类 SLE 进展。我们的遗传关联数据确定了 IRF8 的几种潜在 SLE 易感变异（最佳 p=1.2x10-22）和跨多个种族的 SLC15A4（最佳 p=1.5x10-21）。然而，尽管实力强劲相关性、特定致病变异及其潜在的分子机制尚未确定。使用生物信息学，我们预测几个相关的变异体是cis-eQTL，具有调节基因的作用表达。使用荧光素酶和 ChIP-qPCR，我们通过实验验证了几种等位基因特异性效应预测的功能变异。由于 IFN 基因特征是 SLE 的一个显着特征，我们假设全面的跨种族绘图（TEM），然后通过功能遗传学进行实验验证，包括相关免疫细胞中的遗传和表观遗传编辑，将识别因果变异及其功能 IFN-I 产生的后果。我们的研究团队拥有专业知识、资源和跟踪记录来发现并表征 SLE 的功能变异。在目标 1 中，我们将从这些中定位 SLE 易感变异体通过对不同种族人群（N>30,000）进行基于插补的综合 TEM 来分析基因来自亚洲人、非洲裔美国人、欧洲裔美国人、埃及人和西班牙人）。有前途的变体，特别是估算和低频变异，将通过额外的确认性基因分型进行验证。我们将通过评估与临床亚表型的关联来阐明遗传和临床异质性自身抗体。在目标 2 中，我们将通过实验验证假定变体作为调节剂的功能相关性基因表达和 IFN-I 的产生。我们将使用培养细胞 (THP-1) 和原代免疫细胞（pDC、单核细胞）来自 SLE 患者和对照。从该项目中获得的见解将有助于定义风险等位基因如何诱发系统性红斑狼疮的分子机制，并可能定义新的药物/治疗方法 SLE 的未来目标。