Biophysical parameters of self-reactive TCR engagement in T1D

T1D 中自反应 TCR 参与的生物物理参数

• 批准号: 10681917
• 负责人: Maria Bettini
• 金额: $ 74.95万
• 依托单位: UNIVERSITY OF UTAH
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-03-01 至 2028-02-29
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10681917
• 关键词: Affinity; Alleles; Antigen Presentation; Antigens; Autoantigens; Autoimmune; Autoimmune Diabetes; Autoimmune Diseases; Autoimmunity; Beta Cell; Binding; CD4 Positive T Lymphocytes; CDR1 gene; Cell physiology; Cells; Complementarity Determining Regions; Complex; Data; Disease; Disease Progression; Eragrostis; Exhibits; Experimental Animal Model; FOXP3 gene; Failure; Family; Functional disorder; Genetic; Goals; HLA-DR4 Antigen; Histocompatibility; Human; Insulin-Dependent Diabetes Mellitus; Knowledge; Measurement; Measures; Mediating; Modeling; Mus; Outcome; Peptide Receptor; Peptides; Predisposition; Prevalence; Process; Proteins; Public Health; Publishing; Receptor Activation; Regulatory T-Lymphocyte; Risk Factors; Specificity; Structure; Surveys; System; T cell response; T cell therapy; T-Cell Activation; T-Cell Antigen Receptor Specificity; T-Cell Development; T-Cell Receptor; T-Lymphocyte; TCR Activation; Technology; Testing; Therapeutic; Treg therapy; Work; antigen-specific T cells; autoreactive T cell; beta Chain Antigen T Cell Receptor; biophysical properties; design; diabetogenic; effector T cell; humanized mouse; improved; insight; mechanical force; new technology; novel; response

ABSTRACT Major histocompatibility loci (MHC) are the largest genetic contributors to autoimmune susceptibility, including type 1 diabetes. Our novel observations show that biophysical parameters of T cell receptor interactions with peptide-MHC are altered in the context of susceptible MHC alleles. Dissecting the interaction between T cell receptor and self-antigens requires sensitive technologies to measure the affinity and bond lifetimes. T cells apply force to the bond between TCR and pMHC antigenic complex, which is ultimately reflected by changes in how long the proteins interact. We have surveyed affinities, bond lifetimes, and force that form during T cell receptor interaction with model, infectious, and self-antigens presented on non-autoimmune I-Ab and compared these observations with I-Ag7 autoimmune MHC restricted T cells. We consistently observed 2-fold difference in force between effector and Foxp3+ regulatory T cells in non-autoimmune MHC restricted responses, with Tregs pulling higher 20pN force. However, I-Ag7 restricted effector T cells are capable of pulling similar high 20pN force, and Tregs loose the 2-fold force advantage. Moreover, human-derived beta cell antigen specific TCR restricted to autoimmune HLA-DR4 exhibited similar high 20pN force. Our overall hypothesis is that Foxp3+ Treg efficacy is dependent on peak TCR force levels that differ 2-fold from T conventional cells, this difference is absent in the context of autoimmune MHCs. How structural components of autoimmune MHC, peptide, and TCR control the stability of the TCR/pMHC interaction is not fully resolved, especially in the context of force measurements. Our recently published and unpublished observations point to CDR2 loops of the TCR as important in establishing the level of force. Moreover, it is unknown how susceptible MHC effects Treg suppressive function, and why Tregs falter during T1D. Therefore, a thorough understanding of the beta cell- specific reactivity of effector and regulatory T cells is needed to fully understand and potentially exploit their therapeutic potential for treatment of autoimmune diabetes. We have devised two aims to test this hypothesis: Aim 1. Determine TCR biophysical parameters restricted by autoimmune MHC and their impact on autoimmune and regulatory T cell function; and Aim 2. Determine structural components of TCR that specifically regulate the force and bond-lifetime, but do not influence specificity or affinity of the interaction. This project will be the first to investigate various levels of force/bond lifetimes as indicators for T cell function and loss of Treg function in autoimmunity, and connect TCR affinity vs force to the ultimate outcome in disease. Furthermore, it will provide novel insight into the mechanisms governing dysfunction of T cell tolerance during T1D.

抽象的 主要组织相容性位点 (MHC) 是自身免疫易感性的最大遗传因素，包括 1 型糖尿病。我们的新观察结果表明，T 细胞受体相互作用的生物物理参数 肽-MHC 在易感 MHC 等位基因的背景下发生改变。剖析 T 细胞之间的相互作用 受体和自身抗原需要灵敏的技术来测量亲和力和键寿命。 T细胞 对 TCR 和 pMHC 抗原复合物之间的键施加作用力，最终反映在 蛋白质相互作用多长时间。我们调查了 T 细胞过程中形成的亲和力、键寿命和力 受体与非自身免疫 I-Ab 上呈现的模型抗原、传染性抗原和自身抗原的相互作用并进行比较 这些观察结果与 I-Ag7 自身免疫 MHC 限制性 T 细胞有关。我们始终观察到 2 倍的差异 在非自身免疫性 MHC 限制性反应中，效应细胞和 Foxp3+ 调节性 T 细胞之间有效， Tregs 拉动更高的 20pN 力。然而，I-Ag7 限制性效应 T 细胞能够达到类似的高水平 20pN 的力量，Treg 失去了 2 倍的力量优势。此外，人源性β细胞抗原特异性 仅限于自身免疫 HLA-DR4 的 TCR 表现出类似的高 20pN 力。我们的总体假设是 Foxp3+ Treg 功效取决于峰值 TCR 力水平，与传统 T 细胞相差 2 倍，这种差异 在自身免疫性 MHC 中不存在。自身免疫性 MHC、肽和 TCR控制TCR/pMHC相互作用的稳定性尚未完全解决，特别是在力的背景下 测量。我们最近发表和未发表的观察结果表明 TCR 的 CDR2 环为 对于确定武力水平很重要。此外，MHC 对 Treg 的影响程度尚不清楚。 抑制功能，以及为什么 Tregs 在 T1D 期间会步履蹒跚。因此，彻底了解 β 细胞—— 需要效应 T 细胞和调节 T 细胞的特异性反应才能充分理解并潜在地利用它们 治疗自身免疫性糖尿病的治疗潜力。我们设计了两个目标来检验这个假设： 目的1.确定受自身免疫MHC限制的TCR生物物理参数及其对自身免疫的影响 和调节性T细胞功能；目标 2. 确定专门调节 TCR 的结构成分 力和键寿命，但不影响相互作用的特异性或亲和力。该项目将是第一个 研究不同水平的力/键寿命作为 T 细胞功能和 Treg 功能丧失的指标 自身免疫，并将 TCR 亲和力与力量与疾病的最终结果联系起来。此外，它将提供 对 T1D 期间 T 细胞耐受功能障碍的机制有新的见解。