AIP inhibition of IRF7 and innate antiviral signaling

AIP 抑制 IRF7 和先天抗病毒信号

基本信息

批准号：
10217831
负责人：
EDWARD W HARHAJ
金额：
$ 23.1万
依托单位：
PENNSYLVANIA STATE UNIV HERSHEY MED CTR
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-04-15 至 2023-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10217831
关键词：
2019-nCoV ARA9 protein Adjuvant Agonist Antiviral Agents Antiviral Response Aryl Hydrocarbon Receptor Autoimmunity Automobile Driving Biochemical COVID-19 Cells DNA Binding Data Dioxins Disease Embryo Environmental Risk Factor Enzymes Equilibrium Feedback Fibroblasts Generations Genes Homeostasis Hydrocarbons IRF3 gene Immune Immune response Immune signaling Inflammation Inflammation Mediators Influenza A virus Innate Immune Response Interferon Type I Interferon-alpha Interferon-beta Interferons Investigation Knowledge Kynurenine Ligands Link Maps Mass Spectrum Analysis Mitochondria Molecular Molecular Chaperones Mus Myeloid Cells Natural Immunity Nuclear Nuclear Translocation Nucleic Acids Pathogenesis Pathogenicity Pathway interactions Phosphorylation Phosphorylation Site Phosphotransferases Play Predisposition Production Protein Inhibition Proteins RIPK1 gene RNA Virus Infections RNA Viruses Receptor Signaling Regulation Resistance Role Serine Signal Transduction Specificity TANK-binding kinase 1 TBK1 gene Testing Tetrachlorodibenzodioxin Therapeutic Threonine Toxic Environmental Substances Transcription Coactivator Transcriptional Activation Tryptophan Tryptophan 2,3 Dioxygenase Vaccines Vesicular stomatitis Indiana virus Viral Viral Pathogenesis Virus Virus Diseases Virus Replication Xenobiotics antiviral immunity aryl hydrocarbon receptor ligand base cell type cytokine release syndrome experimental study in vivo influenza infection inhibitor/antagonist insight interferon regulatory factor-7 mimetics mutant novel prevent receptor reconstitution recruit response small molecule transcription factor

项目摘要

ABSTRACT Interferon regulatory factor 7 (IRF7) is a transcription factor known as the master regulator of the type I interferon (IFN) response; however, it remains unclear how IRF7 is negatively regulated to restore immune homeostasis after viral infections are resolved. We have identified aryl hydrocarbon receptor interacting protein (AIP) as a negative regulator of IRF7 that plays essential roles in the inhibition of IRF7 activation. AIP regulates the aryl hydrocarbon receptor (AhR), a ligand-activated receptor of the host xenobiotic response to environmental toxins such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCCD). We found that AIP interacts with IRF7 and this interaction is further enhanced by virus infection. Aip–/– murine embryonic fibroblasts (MEFs) produce significantly more type I IFN compared to wild-type cells infected with virus, thus rendering these cells highly resistant to virus infection. AIP antagonizes the nuclear localization of IRF7 to prevent the transcriptional activation of type I IFN genes. However, key questions remain regarding the roles of AIP and AhR in the regulation of IRF7 and innate immune responses. What is the molecular mechanism underlying specificity for AIP regulation of IRF7 and antiviral innate immunity? Given the established functional links between AIP and AhR, does AhR inhibit IRF7, and is AIP required for the inhibition of antiviral signaling by AhR ligands? In preliminary studies, we have identified AIP as a novel substrate of the noncanonical IkB kinase TBK1 (TANK- binding kinase 1), and three putative phosphorylation sites were mapped by mass spectrometry. Furthermore, treatment of cells with the AhR agonist L-kynurenine (L-Kyn) significantly enhanced the replication of vesicular stomatitis virus, providing evidence that AhR signaling inhibits the innate antiviral response. AhR interacts with IRF7 suggesting that IRF7 may be a target of AhR in innate immune signaling. Indoleamine 2,3-dioxygenase (IDO) is the rate-limiting enzyme in the generation of immune regulatory tryptophan metabolites, including the AhR ligand L-Kyn. IDO is induced by IFN during virus infection suggesting that IDO participates in the negative regulation of innate immune signaling. The central hypothesis driving these investigations is that AIP and AhR cooperate as a functional unit to inhibit IRF7 and virus-induced type I IFN by a two-step negative feedback mechanism instigated by TBK1 and the IFN axis. We will test our hypothesis experimentally with the following Specific Aims: 1) Define the role of AIP phosphorylation in the inhibition of IRF7 and innate signaling, and 2) Determine the role of AIP in the regulation of AhR during virus infection. Completion of these studies may provide new mechanistic insight into how environmental factors can influence innate immunity to virus infection and may provide rationale for the use of AhR agonists or antagonists as an approach to fine-tune host innate immune responses in pathogenic settings such as autoimmunity or virus-triggered cytokine storms (e.g. influenza A or SARS-CoV2/COVID-19).

抽象的干扰素调节因子7（IRF7）是转录因子，称为I型的主调节剂干扰素（IFN）响应；但是，目前尚不清楚如何对IRF7进行负调节以恢复免疫病毒感染后的稳态解决。我们已经鉴定出芳基烃受体相互作用蛋白（AIP）作为IRF7的负调节剂，在抑制IRF7激活中起着重要作用。 AIP调节芳基碳氢化合物受体（AHR），一种宿主异种生物反应的配体激活受体环境毒素，例如2,3,7,8-四氯迪本佐-P-二恶英（TCCD）。我们发现AIP与 IRF7和这种相互作用通过病毒感染进一步增强。 AIP - / - 鼠类胚胎成纤维细胞（MEFS）与感染病毒感染的野生型细胞相比，产生更多的I型IFN，从而渲染这些细胞对病毒感染具有高度抗性。 AIP拮抗IRF7的核定位以防止转录 I型IFN基因的激活。但是，关于AIP和AHR在 IRF7和先天免疫反应的调节。什么是什么分子机制的特异性 IRF7和抗病毒先天免疫的AIP调节？鉴于AIP和 AHR，AHR是否抑制IRF7，并且AIP是否需要AHR配体抑制抗病毒信号传导？在初步研究，我们已经将AIP确定为非规范IKB激酶TBK1的新型底物（储罐 - 结合激酶1）和三个假定的磷酸化位点由质谱法映射。此外，用AHR激动剂L-京戊氨酸（L-KYN）处理细胞，显着增强了囊泡的复制口腔炎病毒，提供了AHR信号传导抑制先天抗病毒反应的证据。 AHR与之互动 IRF7表明IRF7可能是先天免疫信号传导中AHR的目标。吲哚胺2,3-二氧酶（IDO）是免疫调节色氨酸代谢物的产生速率限制酶，包括 Ahr配体L-KYN。 IDO在病毒感染期间由IFN诱导，表明IDO参与了负面先天免疫信号传导的调节。推动这些调查的中心假设是AIP和AHR 作为功能单位合作，以抑制IRF7和病毒诱导的I型IFN，由两步负面反馈由TBK1和IFN轴启动的机制。我们将通过以下实验测试我们的假设具体目的：1）定义AIP磷酸化在抑制IRF7和先天信号中的作用，以及2）确定AIP在病毒感染过程中AHR调节中的作用。这些研究的完成可能提供有关环境因素如何影响病毒感染的先天免疫的新机械洞察力并可能为使用AHR激动剂或反对者作为微调宿主先天的方法提供理由病原环境中的免疫反应，例如自身免疫性或病毒触发的细胞因子风暴（例如， actractza或sars-cov2/covid-19）。