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：
9895394
负责人：
Swapan K. Nath
金额：
$ 21.85万
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 2022-02-28
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9895394
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 Hyperactive behavior 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 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.

抽象的全身性红斑狼疮（SLE或狼疮）是I型干扰素（IFN-I）介导的自身免疫的原型疾病的特征是无数临床表现，包括炎症，致病性自身抗体生产和不可逆的末期损伤（例如肾脏）。 SLE不成比例地折磨女性（九倍高于男性）和非白人种族。亚洲人和非裔美国人的发病率更高，更多严重的疾病表现和比白种人比高加索人更大的器官损伤风险（例如狼疮肾炎）。其他的我们已经报道了几个IFN调节基因，包括IFN调节因子8（IRF8）和溶质载体家族15号4号（SLC15A4）参与SLE敏感性。 IFN是一个细胞因子家族在感染，癌症和自身免疫性中的重要作用。体外证据表明浆细胞类动物树突状细胞（PDC）是主要产生免疫细胞的主要IFN-I，与SLE发育密切相关。最近使用两个小鼠模型（IRF8 - / - 敲除和SLC15A4突变体）的研究提供了直接证据表明PDCS 通过IFN-I的过度生产来促进SLE。因此，IRF8和SLC15A4可能与人类有关 SLE进展。我们的遗传关联数据确定了IRF8的几种潜在的SLE易感变体（最佳p = 1.2x10-22）和跨多个种族的SLC15A4（最佳p = 1.5x10-21）。但是，尽管很强尚未定义关联，特定的致病变异及其潜在的分子机制。使用生物信息学，我们预测几种相关的变体是顺式EQTL，在调节基因中的作用表达。使用荧光素酶和ChIP-QPCR，我们在实验验证了几种等位基因特异性效应预测功能变体。由于IFN基因签名是SLE的重要特征，因此我们假设全面的跨种族映射（TEM），然后对功能遗传学进行实验验证，在相关免疫细胞中包括遗传和表观遗传编辑，将识别因果变异及其功能 IFN-I生产的后果。我们的研究团队拥有专业知识，资源和记录记录并表征SLE的功能变体。在AIM 1中，我们将在其中本地位置sle-prodisposing变体通过在种族多样化的种群中进行全面的基于基于插补的TEM（n> 30,000 来自亚洲人，非裔美国人，欧洲人，埃及人和西班牙裔）。有希望的变体，特别是估算和低频变体，将通过其他确认性基因分型来验证。我们将通过评估与临床亚表征和临床的关联来阐明遗传和临床异质性自动抗体。在AIM 2中，我们将通过实验验证推定变体作为调节器的功能相关性基因表达和IFN-I产生。我们将同时使用培养的细胞（THP-1）和原代免疫细胞（PDC，单核细胞）来自SLE患者和对照组。从该项目中获得的见解将有助于定义分子机制的风险等位基因如何易于SLE，并可能定义新的药物/治疗性将来SLE的目标。