Defining the Role of Thymic Tolerance in the Pathogenesis of the COPA syndrome

定义胸腺耐受性在 COPA 综合征发病机制中的作用

基本信息

批准号：
10083697
负责人：
Anthony Shum
金额：
$ 47.31万
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：
2018
资助国家：
美国
起止时间：
2018-01-16 至 2022-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10083697
关键词：
Adoptive Transfer Affect Alleles Animal Model Animals Arthritis Autoantibodies Autoimmune Autoimmune Diseases Autoimmunity B-Lymphocytes Bone Marrow CD4 Positive T Lymphocytes CD8-Positive T-Lymphocytes CD8B1 gene Cells Chimera organism Chronic Childhood Arthritis Coat Protein Complex I Data Defect Disease Disease model Epithelial Flow Cytometry Functional disorder Genes Global Change Goals Golgi Apparatus Grant Hematopoietic Homeostasis Human Immune Immune Tolerance Immune system Immunohistochemistry Immunologics Immunosuppressive Agents Impairment Inflammatory Inflammatory Arthritis Interstitial Lung Diseases Kidney Diseases Knock-in Mouse Lead Learning Lung Lung diseases Lymphocyte Lymphoid Tissue Maps Mediating Molecular Mononuclear Mouse Strains Movement Mus Mutation Mycophenolate Nude Mice Organ Pathogenesis Pathway interactions Patients Peripheral Phenocopy Population Pre-Clinical Model Proteins Pulmonary Fibrosis Research Personnel Rheumatoid Arthritis Rheumatoid Factor Role Self Tolerance Series Serum Study Subject Syndrome System T memory cell T-Cell Receptor T-Lymphocyte Testing Thymic epithelial cell Thymocyte Development Thymocyte Selection Thymus Gland Tissues Transgenic Mice Transplantation Tumor-infiltrating immune cells aged arthropathies autoreactive T cell clinical Diagnosis cyclic citrullinated peptide experimental study insight mouse model mutant neutrophil novel pre-clinical success thymocyte trafficking transcriptome sequencing

项目摘要

PROJECT SUMMARY: Our lab recently co-discovered the COPA syndrome, an autoimmune disease caused by dominant mutations in the Coatomer subunit alpha (COPA) gene that manifests as inflammatory arthritis and interstitial lung disease (ILD). COPA encodes the COPA subunit of coat protein complex I (COPI). COPI is engaged in the retrograde movement of proteins from the Golgi to the ER and is a vital component of a cell's trafficking machinery. Patients with the COPA syndrome develop high-titer antinuclear or anti-neutrophil cytoplasmic autoantibodies, immune-mediated kidney disease and an increase in CD4+ T helper 17 (Th17) cells, an immune cell subset implicated in autoimmunity. Some patients have findings consistent with rheumatoid arthritis RA including rheumatoid factors or autoantibodies to cyclic citrullinated peptides. All COPA syndrome patients eventually develop interstitial lung disease (ILD) in combination with their arthritis. Generalized immunosuppressive drugs such as mycophenolate have been used to treat patients with limited success, although the ILD typically progresses on treatment and leads to end stage lung fibrosis. We generated a germline point mutant knock-in mouse bearing the exact same E241K mutation as COPA syndrome patients. Preliminary data demonstrates that CopaE241K/+ mice spontaneously develop mononuclear lung infiltrates and an examination of peripheral lymphoid tissues reveals a significant increase in effector memory T cells. Detailed study of developing thymocytes shows a significant increase in mature CD8+ and CD4+ single positive (SP) cell populations, findings that suggest alterations in thymocyte development or selection. CopaE241K/+ mice bred to a T cell receptor transgenic mouse system revealed a defect in the negative selection of CD4+ T cells. Interestingly, reciprocal bone marrow chimera experiments map the selection defect to E241K COPA expression in the thymic stroma. Thus, we hypothesize that a critical precursor to autoimmune disease in the COPA syndrome is aberrant thymocyte selection caused by mutant COPA expression in the thymic epithelium. We propose to pursue this hypothesis by 1) Determining the role of mutant COPA in positive and negative selection of CD4+ and CD8+ T cells 2) Defining the role of the thymic stroma on thymocyte development in CopaE241K/+ mice and 3) Defining the autoimmune features of CopaE241K/+ mice and COPA syndrome subjects. Through our study we seek to determine the role of thymic tolerance in the pathophysiology of the COPA syndrome and establish CopaE241K/+ mice as a preclinical model for the disease. Because the COPA syndrome shares features with other inflammatory joint disorders, our study may provide novel insight into how impaired vesicular trafficking contributes to the pathogenesis of arthritis and ILD by altering the negative selection of autoreactive T cells and causing a defect in central immune tolerance.

项目概要：我们的实验室最近共同发现了 COPA 综合征，这是一种由显性遗传引起的自身免疫性疾病 Coatomer α 亚基 (COPA) 基因突变，表现为炎症性关节炎和间质性关节炎肺部疾病（ILD）。 COPA 编码外壳蛋白复合物 I (COPI) 的 COPA 亚基。 COPI 从事蛋白质从高尔基体到内质网的逆行运动，是细胞运输的重要组成部分机械。 COPA 综合征患者出现高滴度抗核或抗中性粒细胞胞浆自身抗体、免疫介导的肾脏疾病以及 CD4+ T 辅助 17 (Th17) 细胞的增加与自身免疫有关的免疫细胞亚群。一些患者的表现与类风湿一致关节炎RA，包括类风湿因子或环瓜氨酸肽自身抗体。所有 COPA 综合征患者最终会出现间质性肺病 (ILD) 并伴有关节炎。广义的麦考酚酯等免疫抑制药物已用于治疗患者，但效果有限，尽管 ILD 通常会在治疗后进展并导致终末期肺纤维化。我们生成了一种种系点突变敲入小鼠，其具有与 COPA 综合征患者。初步数据表明 CopaE241K/+ 小鼠自发发育单核肺浸润和外周淋巴组织检查显示单核细胞浸润显着增加效应记忆T细胞。对发育中胸腺细胞的详细研究显示成熟 CD8+ 显着增加和 CD4+ 单阳性 (SP) 细胞群，结果表明胸腺细胞发育或选择。 CopaE241K/+ 小鼠与 T 细胞受体转基因小鼠系统交配后发现阴性缺陷 CD4+T细胞的选择。有趣的是，相互骨髓嵌合体实验绘制了选择缺陷 E241K COPA 在胸腺基质中的表达。因此，我们假设自身免疫性疾病的一个关键前兆 COPA 综合征中的疾病是由突变 COPA 表达引起的异常胸腺细胞选择胸腺上皮。我们建议通过 1) 确定突变 COPA 在阳性中的作用来追求这一假设。 CD4+ 和 CD8+ T 细胞的阴性选择 2) 定义胸腺基质对胸腺细胞的作用 CopaE241K/+ 小鼠的发育以及 3) 定义 CopaE241K/+ 小鼠和 COPA 的自身免疫特征综合症科目。通过我们的研究，我们试图确定胸腺耐受在病理生理学中的作用 COPA 综合征并建立 CopaE241K/+ 小鼠作为该疾病的临床前模型。因为科帕综合征与其他炎症性关节疾病有共同的特征，我们的研究可能提供新的见解囊泡运输受损通过改变负性因子而导致关节炎和 ILD 的发病机制自身反应性 T 细胞的选择并导致中枢免疫耐受缺陷。