Unraveling the molecular mechanisms of impaired central tolerance in COPA syndrome

揭示 COPA 综合征中枢耐受受损的分子机制

基本信息

批准号：
10581676
负责人：
Anthony Shum
金额：
$ 68.74万
依托单位：
UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-03-01 至 2027-02-28
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10581676
关键词：
Agonist Animal Model Animals Antinuclear Antibodies Autoantibodies Autoimmune Autoimmune Diseases Autoimmunity Autophagocytosis Binding Bone Marrow CD4 Positive T Lymphocytes Cell Maturation Cell physiology Cells Childhood Chimera organism Chronic Clinical Data Defect Development Disease Epithelium Exhibits Genetic Goals Golgi Apparatus Grant Harvest Image Immune Immune Complex Glomerulonephritis Immunologic Deficiency Syndromes Immunologics Impairment Infection Inflammation Inflammatory Arthritis Interferon Type I Interferons Interstitial Lung Diseases Joints Kidney Knock-in Mouse Lung Lung diseases Malignant Neoplasms Mass Spectrum Analysis Mediating Missense Mutation Molecular Mus Online Mendelian Inheritance In Man Organ Patients Peptides Peripheral Blood Mononuclear Cell Pharmaceutical Preparations Phenotype Proteins Pulmonary Inflammation Role SLEB3 gene STING agonists Shapes Signal Transduction Syndrome System Systemic Lupus Erythematosus Systemic infection T cell response T cell therapy T-Cell Development T-Lymphocyte Testing Thymic epithelial cell Thymocyte Development Thymocyte Selection Thymus Gland Work arthropathies autoreactive T cell cancer therapy central tolerance cytokine ds-DNA experimental study genetic signature in vivo inhibitor insight joint inflammation mouse model mutant novel novel therapeutics pharmacologic small molecule small molecule inhibitor systemic inflammatory response thymocyte thymus transplantation

项目摘要

PROJECT SUMMARY: Our lab discovered COPA syndrome, a monogenic autoimmune disorder that involves inflammation of the lungs, joints and kidneys. We established a mouse model of COPA syndrome by generating CopaE241K/+ knock-in mice that spontaneously developed clinical and immunologic features of patients, including interstitial lung disease (ILD) and increased levels of activated, cytokine-secreting T cells. We performed bone marrow chimera and thymic transplant experiments to reveal that expression of mutant COPA in the thymic stroma is sufficient to cause a defect in negative selection of CD4+ T cells. Our work revealed that a key step in the initiation of disease in COPA syndrome is a breakdown in central tolerance. The goal of this grant is to unravel the mechanisms by which mutant COPA causes impaired thymic tolerance. COPA syndrome presents in childhood with inflammatory arthritis of the small and large joints and lung disease that manifests as pulmonary capillaritis or ILD. Patients develop clinical features that are observed in systemic lupus erythematosus (SLE) including high-titer anti-nuclear antibodies, autoantibodies to double stranded DNA and immune complex glomerulonephritis. In addition, peripheral blood mononuclear cells from all COPA syndrome subjects exhibit a markedly elevated type I interferon stimulated gene signature, a hallmark of SLE. We recently demonstrated that activation of type I interferon (IFN) signaling in COPA syndrome is caused by constitutive activation of the innate immune adapter molecule STING, which is missorted at the Golgi by mutant COPA. Mutant COPA-mediated STING activation upregulates IFNs in immune cells of CopaE241K/+ mice, and remarkably, also within the thymic epithelium. Taken together, this suggests STING has a functional role in the thymus with the potential to alter thymocyte selection and/or development. We hypothesize mutant COPA breaks central tolerance by causing activation of STING in thymic epithelial cells (TEC). We will use our mouse model to determine how activated STING in thymic epithelial cells alters T cell maturation and selection. We will define the cellular and molecular mechanisms by which mutant COPA impairs autophagic flux and determine whether proteins missorted by mutant COPA are involved in STING-induced autophagy. Finally, we will test whether small molecule STING agonists and inhibitors can fine-tune STING signaling in the thymus to alter thymocyte development and selection. Taken together, our work provides new insight into how activated STING in the thymus shapes the T cell repertoire to cause autoimmunity and immune dysregulation. These findings have important implications for settings in which systemic inflammation causes activation of STING in the thymic stroma including cancer therapy and infections.

项目概要：我们的实验室发现了 COPA 综合征，这是一种单基因自身免疫性疾病，涉及炎症肺、关节和肾脏。我们通过生成 CopaE241K/+ 建立了 COPA 综合征小鼠模型基因敲入小鼠自发地表现出患者的临床和免疫学特征，包括间质性特征肺部疾病 (ILD) 和活化的、分泌细胞因子的 T 细胞水平增加。我们进行了骨髓检查嵌合体和胸腺移植实验揭示突变 COPA 在胸腺基质中的表达足以导致 CD4+ T 细胞阴性选择缺陷。我们的工作揭示了启动的关键一步 COPA 综合征的主要疾病是中枢耐受性的崩溃。这笔赠款的目标是解开突变 COPA 导致胸腺耐受性受损的机制。 COPA 综合征在儿童期出现，伴有小关节、大关节和肺部的炎症性关节炎表现为肺毛细血管炎或 ILD 的疾病。患者出现在以下情况中观察到的临床特征：系统性红斑狼疮 (SLE)，包括高滴度抗核抗体、双重自身抗体搁浅 DNA 和免疫复合物肾小球肾炎。此外，来自所有 COPA 综合征受试者表现出 I 型干扰素刺激基因特征显着升高，这是系统性红斑狼疮。我们最近证明，COPA 综合征中 I 型干扰素 (IFN) 信号的激活是由通过先天免疫接头分子 STING 的组成型激活，该分子在高尔基体中被错误分类突变型 COPA。突变 COPA 介导的 STING 激活上调 CopaE241K/+ 小鼠免疫细胞中的 IFN，值得注意的是，也在胸腺上皮内。综上所述，这表明 STING 在以下方面发挥着功能性作用：胸腺具有改变胸腺细胞选择和/或发育的潜力。我们假设突变 COPA 通过引起胸腺上皮细胞 (TEC) 中的 STING 激活来破坏中枢耐受性。我们将使用我们的小鼠模型来确定胸腺上皮细胞中激活的 STING 如何改变 T 细胞成熟和选择。我们将定义突变 COPA 损害的细胞和分子机制自噬流并确定突变 COPA 错配的蛋白质是否参与 STING 诱导自噬。最后，我们将测试小分子STING激动剂和抑制剂是否可以微调STING 胸腺中的信号传导改变胸腺细胞的发育和选择。总而言之，我们的工作提供了新的深入了解胸腺中激活的 STING 如何塑造 T 细胞库以引起自身免疫和免疫失调。这些发现对于全身性炎症的环境具有重要意义引起胸腺基质中 STING 的激活，包括癌症治疗和感染。