Beta-cell self-antigen recognition by diabetogenic CD8 T cells

致糖尿病 CD8 T 细胞识别 β 细胞自身抗原

• 批准号: 10638081
• 负责人: Baoyu Liu
• 金额: $ 38.46万
• 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/10638081
• 关键词: Affinity; Antigen-Presenting Cells; Antigens; Autoantigens; Autoimmune; Autoimmune Diabetes; Autoimmunity; Avidity; Beta Cell; Binding; Biological; Biological Markers; Biophysics; CD8 receptor; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Communication; Cells; Clone Cells; Data; Development; Diabetes Mellitus; Disease; Endowment; Environment; Event; Future; G6PC2 gene; Immune response; Immune system; Immunology procedure; Inbred NOD Mice; Insulin; Insulin-Dependent Diabetes Mellitus; Investigation; Islets of Langerhans; Kinetics; Life; MHC Interaction; Measures; Mediating; Methods; Molecular; Outcome; Pancreas; Pathogenicity; Patient Care; Pattern; Peptide Fragments; Peptide/MHC Complex; Peripheral; Phenotype; Polysaccharides; Reporting; Role; Self Tolerance; Surface; T cell response; T-Cell Receptor; T-Lymphocyte; TCR Activation; Testing; Thymocyte Selection; Thymus Gland; Time; Tissues; Travel; antigen-specific T cells; autoreactive T cell; autoreactivity; central tolerance; diabetes pathogenesis; diabetogenic; effector T cell; glycosylation; insight; mouse model; novel; novel therapeutic intervention; peripheral tolerance; receptor; receptor binding; single molecule; therapeutic target; transcriptomics; two-dimensional

Project summary Type 1 diabetes (T1D) is a result of T-cell mediated destruction of insulin-producing beta-cells in the pancreatic islets. Autoreactive CD8 T cells are required in this “mistaken” immune response but how they drive disease is ill-defined. There are two key time points during the life of autoreactive T cells closely related to disease, namely, their creation in the thymus and activation in the periphery. The former fails to eliminate the potentially pathogenic T cells whereas the latter allows them to travel to and stay in the target tissue to mediate damage. Both events are strictly dependent on recognition of beta-cell self-antigens. However, little is known about how diabetogenic CD8 T cells recognize beta-cell antigens. We have over the years studied T cell antigen recognition using novel ultrasensitive two-dimensional (2D) force-based methods, showing 2D TCR affinity and bond lifetime with peptide:MHC as two main kinetics parameters that dictate thymocyte selection outcome and T cell effector functions. The current project aims to use these 2D methods to define binding kinetics of beta- cell antigen recognition by diabetogenic CD8 T cells in the context of their thymic development, peripheral effector function, and T1D pathogenesis. Our preliminary data show that CD8 T cells form weak bonds with beta-cell antigens during thymocyte selection but increase bond strength upon activation. Such change of self- reactivity is mediated by coreceptor CD8. In contrast, the same parameters did not change for foreign antigen recognition. These data support our central hypothesis that, in autoimmune diabetes, CD8 fundamentally alters self-antigen recognition through modulation of TCR binding kinetics, thereby endowing CD8 T cells with heightened self-reactivity that overcomes self-tolerance to mediate beta-cell destruction. We propose two specific aims to test this hypothesis. In Aim1, we will define 2D affinity and bond lifetime of beta-cell antigen recognition by CD8 T cells. We hypothesize that diabetogenic CD8 T cells, even at a single clonal level, are highly adaptive in antigen recognition such that they use weak binding kinetics to survive central and peripheral tolerance but greatly increase self-reactivity to precipitate disease. We will use a panel of monoclonal diabetogenic TCR cell clones based on the NOD mouse model of T1D to systemically characterize beta-cell antigen recognition during diabetogenic CD8 T cell thymocyte selection and peripheral activation and investigate a causal relationship between plasticity of beta-cell antigen recognition and autoimmune diabetes. In Aim2, we will elucidate the underlying mechanisms of beta-cell antigen recognition. We hypothesize that plasticity of beta-cell antigen recognition by diabetogenic CD8 T cells is due to CD8 binding kinetics with MHC. We will first define the role of CD8 in the overall beta-cell antigen recognition. We will then test a sub- hypothesis that unique patterns of CD8 glycosylation determine adaptability of CD8 binding kinetics by T cell glycan profiling, phenotyping, and single cell transcriptomic analysis.

项目概要 1 型糖尿病 (T1D) 是 T 细胞介导的胰腺中产生胰岛素的 β 细胞破坏的结果 胰岛。这种“错误”的免疫反应需要自身反应性 CD8 T 细胞，但它们如何驱动疾病尚不清楚 定义不明确。自身反应性T细胞一生中有两个关键时间点与疾病密切相关， 即，它们在胸腺中产生并在外周激活。前者未能消除潜在的 致病性 T 细胞，而后者允许它们前往并停留在靶组织中以介导损伤。 这两个事件都严格依赖于β细胞自身抗原的识别。然而，人们对如何 致糖尿病 CD8 T 细胞识别 β 细胞抗原。我们多年来研究T细胞抗原 使用新型超灵敏二维 (2D) 力方法进行识别，显示 2D TCR 亲和力和 肽键寿命：MHC 作为两个主要动力学参数，决定胸腺细胞选择结果和 T 细胞效应功能。当前的项目旨在使用这些 2D 方法来定义 beta- 的结合动力学 致糖尿病 CD8 T 细胞在胸腺发育、外周血中识别细胞抗原 效应器功能和 T1D 发病机制。我们的初步数据表明 CD8 T 细胞与 在胸腺细胞选择过程中结合β细胞抗原，但在激活后增加结合强度。这样的自我改变 反应性由辅助受体 CD8 介导。相反，对于外来抗原，相同的参数没有改变 认出。这些数据支持我们的中心假设，即在自身免疫性糖尿病中，CD8 从根本上改变 通过调节 TCR 结合动力学来识别自身抗原，从而赋予 CD8 T 细胞 自我反应性增强，克服自我耐受性，介导 β 细胞破坏。我们建议两个 具体目的是检验这一假设。在 Aim1 中，我们将定义 β 细胞抗原的 2D 亲和力和键寿命 CD8 T 细胞识别。我们假设致糖尿病的 CD8 T 细胞，即使在单克隆水平上， 抗原识别具有高度适应性，因此它们利用弱结合动力学来生存中枢和外周 耐受性，但大大增加自身反应性，从而引发疾病。我们将使用单克隆抗体组 基于 T1D NOD 小鼠模型的糖尿病 TCR 细胞克隆，用于系统表征 β 细胞 致糖尿病 CD8 T 细胞胸腺细胞选择和外周激活过程中的抗原识别 研究β细胞抗原识别的可塑性与自身免疫性糖尿病之间的因果关系。 在 Aim2 中，我们将阐明 β 细胞抗原识别的潜在机制。我们假设 致糖尿病 CD8 T 细胞识别 β 细胞抗原的可塑性归因于 CD8 与 MHC 的结合动力学。 我们首先定义 CD8 在整个 β 细胞抗原识别中的作用。然后我们将测试一个子 假设 CD8 糖基化的独特模式决定了 T 细胞对 CD8 结合动力学的适应性 聚糖分析、表型分析和单细胞转录组分析。