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

• 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
• 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

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亚基α（COPA）基因突变，表现为炎性关节炎和间质性关节炎。 肺疾病（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抗体， 自身抗体，免疫介导的肾脏疾病和CD 4 + T辅助细胞17（Th 17）细胞的增加， 与自身免疫有关免疫细胞亚群。一些患者的发现与类风湿性关节炎一致 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 患者最终发展为间质性肺病（ILD）并伴有关节炎。广义 免疫抑制药物如霉酚酸盐已用于治疗患者但成功有限， 尽管ILD通常在治疗中进展并导致终末期肺纤维化。 我们产生了一个种系点突变敲入小鼠，其携带与E241 K突变完全相同的E241 K突变， COPA综合征患者。初步数据表明，CopaE 241 K/+小鼠自发发育 单核细胞肺浸润和外周淋巴组织检查显示， 效应记忆T细胞对发育中的胸腺细胞的详细研究表明，成熟的CD 8 + T细胞显著增加， 和CD 4+单阳性（SP）细胞群，提示胸腺细胞发育改变的结果，或 选择.与T细胞受体转基因小鼠系统交配的CopaE 241 K/+小鼠在阴性对照中显示缺陷。 选择CD 4 + T细胞。有趣的是，相互骨髓嵌合体实验映射了选择缺陷， E241 K 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体 COPA综合征中的疾病是由胸腺细胞中突变的COPA表达引起的异常胸腺细胞选择。 胸腺上皮我们建议通过以下方式来实现这一假设：1）确定突变型COPA在阳性细胞中的作用， CD 4+和CD 8 + T细胞的阴性选择2）确定胸腺基质对胸腺细胞的作用 3）确定CopaE 241 K/+小鼠和COPA的自身免疫特征 综合征患者 通过我们的研究，我们试图确定胸腺耐受性在肿瘤病理生理学中的作用。 COPA综合征，并建立CopaE 241 K/+小鼠作为该疾病的临床前模型。因为COPA 综合征与其他炎性关节疾病的共同特征，我们的研究可能提供新的见解，如何 受损的囊泡运输通过改变负性的 自身反应性T细胞的选择，并导致中枢免疫耐受的缺陷。