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) 是一种转录因子，被称为 I 型干扰素主调节因子然而，目前尚不清楚 IRF7 是如何通过负调节来恢复免疫的。我们已经鉴定出芳基烃受体相互作用蛋白。 (AIP) 作为 IRF7 的负调节因子，在抑制 IRF7 激活中发挥重要作用。芳基碳氢化合物受体（AhR），一种配体激活的宿主异生素反应受体我们发现 AIP 会与 2,3,7,8-四氯二苯并-对二恶英 (TCCD) 等环境毒素发生相互作用。 IRF7 和这种相互作用通过病毒感染进一步增强。与感染病毒的野生型细胞相比，它们显着产生更多的 I 型干扰素，从而使这些细胞 AIP对病毒感染具有高度抵抗力，拮抗IRF7的核定位以阻止转录。然而，关于 AIP 和 AhR 在 I 型 IFN 基因的激活中的作用仍然存在关键问题。 IRF7 和先天免疫反应的调节特异性的分子机制是什么。鉴于 AIP 和 IRF7 之间已建立的功能联系，AIP 对 IRF7 和抗病毒先天免疫的调节？ AhR，AhR 是否抑制 IRF7，AIP 是否需要 AhR 配体抑制抗病毒信号传导？初步研究中，我们已确定 AIP 是非经典 IkB 激酶 TBK1 (TANK- 结合激酶 1)，并通过质谱法绘制了三个假定的磷酸化位点。此外，用 AhR 激动剂 L-犬尿氨酸 (L-Kyn) 处理细胞可显着增强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。 IRF7 表明 IRF7 可能是先天免疫信号传导中 AhR 的靶标。 (IDO) 是免疫调节色氨酸代谢物产生的限速酶，包括 AhR 配体 L-Kyn 在病毒感染期间由 IFN 诱导，表明 IDO 参与了负作用。驱动这些研究的中心假设是 AIP 和 AhR。作为一个功能单元，通过两步负反馈抑制 IRF7 和病毒诱导的 I 型 IFN TBK1 和 IFN 轴引发的机制我们将通过以下实验检验我们的假设。具体目标：1) 定义 AIP 磷酸化在抑制 IRF7 和先天信号传导中的作用，2) 完成这些研究可能会确定 AIP 在病毒感染期间调节 AhR 中的作用。为环境因素如何影响对病毒感染的先天免疫提供新的机制见解并可能为使用 AhR 激动剂或拮抗剂作为微调宿主先天性的方法提供理论依据致病环境中的免疫反应，例如自身免疫或病毒触发的细胞因子风暴（例如甲型流感或 SARS-CoV2/COVID-19）。