Molecular Dissection of Insulin Targeting in Anti-Islet Autoimmunity

胰岛素靶向抗胰岛自身免疫的分子解析

• 批准号: 9104151
• 负责人: Maki Nakayama
• 金额: $ 33.82万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-20 至 2018-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9104151
• 关键词: Address; Adverse effects; Affinity; Amino Acids; Animal Model; Animals; Antigens; Autoantibodies; Autoimmune Diseases; Autoimmunity; B-insulin; Binding; CD8B1 gene; Clinical Research; Complex; Development; Diabetes Mellitus; Disease; Dissection; Epitopes; Frequencies; Genes; Goals; Health; High-Throughput Nucleotide Sequencing; Histocompatibility Antigens Class II; Human; Immune system; Immunological Diagnosis; Immunotherapeutic agent; Immunotherapy; Inbred NOD Mice; Individual; Inflammation; Insulin; Insulin-Dependent Diabetes Mellitus; Knock-out; Knowledge; Lead; Major Histocompatibility Complex; Molecular; Mus; Mutate; Nature; Orthologous Gene; Pancreas; Pathway interactions; Patients; Peptides; Play; Predisposition; Regulatory T-Lymphocyte; Research; Research Design; Risk; Role; Specificity; Staging; Structure of beta Cell of islet; T-Cell Receptor; T-Cell Receptor Genes; T-Lymphocyte; T-Lymphocyte Epitopes; Techniques; Testing; Time; Tissues; alpha-beta T-Cell Receptor; base; congenic; design; endocrine pancreas development; insight; islet; mouse model; organ growth; prevent; response; therapy development

DESCRIPTION (provided by applicant): The major histocompatibility complex (MHC) class II locus is strongly associated with the risk of type 1 diabetes, and tissue specificity of the autoimmunity causing diabetes is likely to be determined by the trimolecular complex composed of an MHC molecule, an antigen, and a T cell receptor (TCR). We hypothesize that the interactions between components of this trimolecular complex, all of which are encoded in the germline, determines the nature of T cells involved in the development of type 1 diabetes. Targeting of an insulin B chain 9-23 amino acid peptide (insulin B:9-23) is highly likely to be an essential determinant in the initiation of islet inflammation in the spontaneous diabetes animal model, NOD mouse. We recently discovered that TCRs containing the germline-encoded variable gene (Vgene) sequence called "TRAV5D-4" play a critical role to induce anti-islet autoimmunity via the recognition of insulin B:9-23 peptide. Thus, the trimolecular complex consisting of the insulin B:9-23 peptide and TRAV5D-4 TCR alpha chain plays a key role in developing anti-islet autoimmunity; however, how T cells expressing TRAV5D-4 TCRs contribute to the initiation and development of the disease remains to be elucidated. Given evidence that the DQ8 diabetes- susceptible HLA class II molecule is an ortholog of NOD I-Ag7 presenting the insulin B:9-23 peptide and that T cells expressing TRAV13-1 (human ortholog of TRAV5D-4) TCR alpha chains dominantly exist in the pancreas of a type 1 diabetes patient having DQ8, the ultimate goal of this proposal is to verify a proof of concept that insulin targetig by a specific germline-encoded TCR Vgene motif plays a critical role in the development of islet autoimmunity. In this proposal, we aim to determine the molecular mechanism of how TCRs, in particular those containing TRAV5D-4, target the critical peptide, insulin B:9-23, to initiate isle inflammation using the NOD mouse model (Aim 1), and to determine whether T cells expressing TRAV5D-4 are essential for diabetes development in NOD mice (Aim 2). If the development of anti-islet autoimmunity is completely suppressed in the absence of TRAV5D-4, targeting only T cells expressing such essential TRAV genes will enable us to develop a robust immunotherapy with the minimum of side effects. Finally, we will pursue the hypothesis that there is a conceptually similar interaction in the human trimolecular complex consisted of the insulin B:9-23 peptide and TRAV13-1 TCR Vgene motif underlying susceptibility to human type 1 diabetes (Aim 3). Findings from this proposal will provide a deeper understanding of the principles underlying the initiation of islet autoimmunity via the interaction within the insulin trimolecular complex, which will ultimately to be applied to design antigen-based immunodiagnostic and immunotherapeutic clinical studies for type 1diabetes in humans.

描述（申请人提供）：主要组织相容性复合物（MHC）II类基因座与1型糖尿病的风险密切相关，引起糖尿病的自身免疫的组织特异性很可能是由MHC分子组成的三分子复合物决定的、抗原和T细胞受体(TCR)。我们假设这种三分子复合物各成分之间的相互作用（所有这些成分均在种系中编码）决定了参与 1 型糖尿病发展的 T 细胞的性质。在自发性糖尿病动物模型 NOD 小鼠中，靶向胰岛素 B 链 9-23 氨基酸肽（胰岛素 B:9-23）很可能是引发胰岛炎症的重要决定因素。我们最近发现，含有名为“TRAV5D-4”的种系编码可变基因 (Vgene) 序列的 TCR 在通过识别胰岛素 B:9-23 肽诱导抗胰岛自身免疫方面发挥着关键作用。因此，由胰岛素B:9-23肽和TRAV5D-4 TCR α链组成的三分子复合物在抗胰岛自身免疫的发展中发挥着关键作用；然而，表达 TRAV5D-4 TCR 的 T 细胞如何促进疾病的发生和发展仍有待阐明。有证据表明，DQ8 糖尿病易感性 HLA II 类分子是呈递胰岛素 B:9-23 肽的 NOD I-Ag7 的直向同源物，并且表达 TRAV13-1（TRAV5D-4 的人类直向同源物）的 T 细胞主要存在 TCR α 链在患有 DQ8 的 1 型糖尿病患者的胰腺中，该提案的最终目标是验证胰岛素通过特定种系编码的 TCR 靶向的概念证明V基因基序在胰岛自身免疫的发展中起着至关重要的作用。在本提案中，我们的目标是利用 NOD 小鼠模型确定 TCR（特别是含有 TRAV5D-4 的 TCR）如何靶向关键肽胰岛素 B:9-23 引发岛炎症的分子机制（目标 1），以及确定表达 TRAV5D-4 的 T 细胞对于 NOD 小鼠的糖尿病发展是否至关重要（目标 2）。如果在缺乏 TRAV5D-4 的情况下完全抑制抗胰岛自身免疫的发展，那么仅针对表达此类必需 TRAV 基因的 T 细胞将使我们能够开发出副作用最小的强大免疫疗法。最后，我们将提出这样的假设：由胰岛素 B:9-23 肽和 TRAV13-1 TCR V 基因基序组成的人类三分子复合物中存在概念上相似的相互作用，该相互作用是人类 1 型糖尿病的易感性（目标 3）。该提案的结果将有助于更深入地了解通过胰岛素三分子内的相互作用启动胰岛自身免疫的原理 复合体，最终将应用于设计针对人类 1 型糖尿病的基于抗原的免疫诊断和免疫治疗临床研究。