Insulin specific T cell response shaped by diabetes protective MHC class II molecules

由糖尿病保护性 MHC II 类分子形成的胰岛素特异性 T 细胞反应

• 批准号: 10444416
• 负责人: AARON W MICHELS
• 金额: $ 41.14万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-01-11 至 2027-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10444416
• 关键词: Alleles; Amino Acid Substitution; Amino Acids; Animal Model; Anti-Inflammatory Agents; Antigens; Autoantigens; Autoimmune Diabetes; Autoimmune Diseases; Autoimmunity; B-Cell Antigen Receptor; Bar Codes; Binding; Biological Assay; Bystander Suppression; CD4 Positive T Lymphocytes; Cell Line; Cell physiology; Cells; Chromogranin A; Clinical; Complex; DNA; Data; Defect; Development; Diabetes Mellitus; Disease; Epitopes; Event; FOXP3 gene; Funding; Gene Expression; Generations; Genetic Determinism; Goals; HLA Antigens; Health; Histocompatibility Antigens Class II; Human; IL2RA gene; Immune; Inbred NOD Mice; Individual; Insulin; Insulin-Dependent Diabetes Mellitus; Interleukin-10; Knock-out; Knowledge; Label; Lead; Link; Major Histocompatibility Complex; Mediating; Molecular; Molecular Target; Mus; Organ Donor; Pancreas; Pathway interactions; Patients; Peptides; Phenotype; Population; Positioning Attribute; Predisposition; Process; Proinsulin; Proliferating; Regulation; Regulatory T-Lymphocyte; Research; Resistance; Risk; Role; Shapes; Specificity; T cell receptor repertoire sequencing; T cell response; T-Cell Receptor; T-Lymphocyte; TNFRSF10A gene; Testing; anergy; antigen test; antigen-specific T cells; autoreactive T cell; cell immortalization; cytokine; diabetes risk; effector T cell; enzyme linked immunospot assay; improved; insight; insulin dependent diabetes mellitus onset; islet; lymph nodes; molecular phenotype; mouse model; non-diabetic; peripheral blood; prevent; response; single-cell RNA sequencing; therapy design

Project Summary The major genetic determinant in susceptibility to or protection from many autoimmune diseases reside in the human major histocompatibility complex (MHC) that contains the human leukocyte antigen (HLA) region. In type 1 diabetes (T1D), particular HLA class II alleles (e.g. DR4/DQ8) increase the risk for developing disease, whereas others (e.g., DQ6, DQB1*06:02) lead to dominant protection. MHC class II molecules function to present processed antigens to T cells, and the MHC class II−peptide−T cell receptor (TCR) forms a trimolecular complex involving the presentation of self-peptides that shape autoreactive T cell responses in autoimmunity. The goal of our studies is to bridge the gap of knowledge in diabetes-protective MHC class II molecules and insulin-specific T cell responses. Data from the last funding period indicates that T1D protective MHC class II molecules (murine IAb ≈ human DQ6) present insulin, and specifically insulin B chain amino acids 9-23 (B:9-23) to activate CD4 T cells with a regulatory phenotype (Tregs). In the NOD mouse model of spontaneous autoimmune diabetes, insulin-specific FoxP3+ Tregs are present but fail to prevent diabetes onset. The presence of IAb in addition to the NOD diabetes conferring IAg7 MHC class II abrogates all diabetes development. With fluorescent B:9-23 tetramers on each class II molecule, we are able to detect B:9-23/IAb type 1 regulatory T cells (Tr1 cells) in the pancreatic lymph nodes in NOD mice heterozygous for IAb/IAg7, while insulin-IAg7 T cells are less frequent and not activated. Similarly in non-diabetic humans with DQ6, we are able to proliferate Tregs from the peripheral blood that respond to insulin B:9-21/DQ6. Single cell RNA sequencing of these proliferated insulin-Tregs reveals a distinct Tr1 cluster that secrete the anti-inflammatory cytokine, IL-10. However, the necessity for these insulin-Tregs and mechanisms by which these cells confer diabetes resistance remains to be determined. In specific aim 1, we will determine the molecular phenotype and necessity for insulin-Tregs to protect against diabetes development in murine models with a diabetes-resistant MHC class II molecule. Specific aim 2 focuses on parallel studies in humans to identify the protective features of insulin-Tregs restricted to DQ6 and those to DQ8 in individuals with and without T1D. The successful completion of this proposal will provide insights into the function and molecular phenotype of insulin-Tregs restricted to diabetes-protective MHC class II molecules and determine their direct role in conferring diabetes protection, thus aiding the design of therapies that may improve Treg function to treat the underlying autoimmunity in T1D.

项目摘要 对许多自身免疫性疾病的易感性或保护作用的主要遗传决定因素存在于 人类主要组织相容性复合体（MHC），包含人类白细胞抗原（HLA）区域。型 1型糖尿病（T1 D），特别是HLA II类等位基因（例如DR 4/DQ 8）增加了发生疾病的风险， 而其它（例如，DQ 6，DQB 1 *06：02）导致显性保护。MHC II类分子的功能是呈递 将抗原加工成T细胞，与MHC II类肽-T细胞受体（TCR）形成三分子复合物 涉及在自身免疫中形成自身反应性T细胞应答的自身肽的呈递。的目标 我们的研究是为了弥补糖尿病保护性MHCII类分子和胰岛素特异性 T细胞反应。 来自上一个资助期的数据表明，T1 D保护性MHC II类分子（鼠IAb和人IAb）在T1 D中的表达与T1 D的表达无关。 DQ 6）呈递胰岛素，特别是胰岛素B链氨基酸9-23（B：9-23），以活化CD 4 T细胞， 调节表型（TclA）。在自发性自身免疫性糖尿病NOD小鼠模型中，胰岛素特异性 FoxP 3 + T细胞存在，但不能预防糖尿病发作。除了NOD糖尿病之外， 赋予IAg 7 MHC II类消除了所有糖尿病的发展。具有荧光B：每个上9-23个四聚体 II类分子，我们能够检测到B：9-23/IA B 1型调节性T细胞（Tr 1细胞 NOD小鼠中IAb/IAg 7杂合的淋巴结，而胰岛素-IAg 7 T细胞不太常见且不活化。 类似地，在患有DQ 6的非糖尿病患者中，我们能够从外周血中增殖TCL 4， 对胰岛素B有反应：9-21/DQ 6。对这些增殖的胰岛素-T细胞进行单细胞RNA测序， Tr 1簇分泌抗炎细胞因子IL-10。然而，这些胰岛素的必要性， 这些细胞赋予糖尿病抗性的机制仍有待确定。具体目标1： 确定分子表型和必要性胰岛素-T β，以防止糖尿病的发展， 用抗糖尿病MHC II类分子的鼠模型。具体目标2侧重于以下平行研究： 在患有糖尿病的个体中， 没有T1 D。该提案的成功完成将提供深入了解功能和分子 胰岛素-T细胞表型局限于糖尿病保护性MHC II类分子，并确定其直接 在赋予糖尿病保护中的作用，从而帮助设计可以改善Treg功能的治疗方法， T1 D中潜在的自身免疫性