Thymic negative selection in human T1D immune systems

人类 T1D 免疫系统中的胸腺负选择

• 批准号: 9808304
• 负责人: Megan Sykes
• 金额: $ 23.87万
• 依托单位: COLUMBIA UNIVERSITY HEALTH SCIENCES
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-06-20 至 2021-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9808304
• 关键词: Address; Adult; Affect; Antigen Presentation; Antigens; Apoptosis; Autoantigens; Autoimmune Diseases; Autoimmune Process; Autoimmunity; Beta Cell; Biological Assay; Biological Models; Blood; Cells; Data; Defect; Development; Diabetes Mellitus; Disease; Epitopes; Event; Exhibits; Failure; Generations; Genes; Genetic; Genetic Determinism; Genetic Risk; Genetic study; HLA-DQ8 antigen; Hematopoietic stem cells; Homeostasis; Human; IL2RA gene; Immune; Immune System Diseases; Immune Tolerance; Immune system; Immunological Models; Impairment; In Vitro; Inbred NOD Mice; Individual; Insulin; Insulin deficiency; Insulin-Dependent Diabetes Mellitus; Investigation; Knockout Mice; Lead; Lymphocyte; Methods; Modeling; Monitor; Mus; Mutate; Non obese; Organ Culture Techniques; Organ Donor; PTPN22 gene; Pancreas; Pathogenesis; Pathway interactions; Patients; Peripheral; Phenotype; Prevention strategy; Proteins; Research; Rheumatoid Arthritis; Risk; Role; Signaling Molecule; Single Nucleotide Polymorphism; Stem cells; Structure of beta Cell of islet; Systemic Lupus Erythematosus; T-Cell Receptor; T-Lymphocyte; Testing; Thymic Tissue; Thymus Gland; Time; Transgenes; Transgenic Organisms; Uncertainty; Variant; autoreactive T cell; base; central tolerance; diabetes mellitus genetics; diabetic; diabetogenic; fetal; genetic variant; human fetal thymus; human model; humanized mouse; immune system function; in vivo; in vivo Model; innovation; insight; lentivirally transduced; migration; mouse model; novel; peripheral tolerance; prevent; reconstitution; risk variant; therapeutic development; type I diabetic

In healthy individuals, central and peripheral immune tolerance mechanisms prevent autoimmune disease. One or more of these mechanisms is disrupted in Type 1 diabetes (T1D) patients, resulting in autoimmune destruction of insulin-producing pancreatic beta cells. In the NOD mouse model, defects in thymic negative selection have been strongly implicated in disease development. Introduction of an insulin-reactive T-cell receptor (TCR) derived from a T1D patient to peripheral T cells of humanized mice can initiate diabetes, consistent with the notion that escape of autoreactive T-cells from negative selection can promote disease. On the other hand, beta cell antigen-reactive T-cells have also been isolated from the blood of healthy control (HC) individuals, raising the possibility that defective peripheral tolerance mechanisms may be most important in promoting T1D. Genetic studies have identified over 60 risk variants for T1D, including associations with genes implicated in deletion of developing autoreactive T cells during thymic negative selection. To date, however, there has been no method available to model human patient-specific thymic selection, resulting in uncertainty about the role of defects in this pathway in promoting human autoimmune diseases. We hypothesize that there are specific hematopoietic stem cell (HSC)-intrinsic and thymus-intrinsic genetic variants in T1D individuals that lead to the failure of negative selection of diabetogenic T-cell receptors (TCRs) in the thymus. We have established a Personalized Immune (PI) mouse model that allows us to generate an adult human's immune system de novo in immunodeficient NOD/LtSz-scid IL2R gamma null mice (NSG) mice receiving patient HSCs and a partially HLA-matched fetal thymus graft. We have also demonstrated that adult patient HSCs can be lentivirally transduced to express a TCR and subsequently used to reconstitute NSG mice or human thymus tissue in thymic organ culture assays. We have demonstrated that a diabetogenic insulin B(9-23)/HLA-DQ8- specific autoreactive TCR is normally deleted within the thymus of humanized mice constructed with HLA-DQ8+ thymic tissue and HSCs. With these data and with access to HSCs from T1D and HC donors and to thymi from the network for Pancreatic Organ Donors with Diabetes (nPOD), we have demonstrated the feasibility of our proposed study. We will use these innovative in vitro and in vivo models to assess whether or not there is a defect in thymic negative selection in immune systems derived from T1D patients and determine whether such defects are intrinsic to the patient HSCs or to T1D thymic tissue. We will associate such defects with genetic risk variants and address hypotheses about the impact of specific variants that may impact negative selection in an HSC- or thymic tissue-dependent manner. These studies will not only provide unprecedented information on the role of defective negative selection in T1D pathogenesis and the genetic determinants of this defect, but will also establish a patient-specific model for assessing negative selection and determining its role in the development of multiple autoimmune diseases.

在健康的个体中，中枢和外周免疫耐受机制可预防自身免疫性疾病。一 或更多这些机制在1型糖尿病（T1D）患者中被破坏，导致自身免疫性破坏 产生胰岛素的胰腺β细胞。在NOD小鼠模型中，胸腺阴性选择中的缺陷具有 与疾病的发展有着强烈的影响。引入胰岛素反应性T细胞受体（TCR） 源自人源性小鼠的T1D患者到外周T细胞可以启动糖尿病，与 自动反应性T细胞从阴性选择中逃脱的观念可以促进疾病。另一方面，beta 细胞抗原反应性T细胞也已从健康对照（HC）个体的血液中分离出来，升高 有缺陷的外围耐受性机制可能在促进T1D方面最重要的可能性。遗传 研究已经确定了T1D的60多种风险变体，包括与与缺失有关的基因的关联 在胸腺阴性选择过程中，会产生自动反应性T细胞。但是，到目前为止，还没有方法 可用于建模人类患者特异性胸腺的选择，从而导致缺陷在 这种促进人类自身免疫性疾病的途径。我们假设有特定的 T1D个体中造血干细胞（HSC） - intrinsic和胸腺intrinsic遗传变异 胸腺中糖尿病性T细胞受体（TCR）的负选择失败。我们有 建立了个性化免疫（PI）鼠标模型，使我们能够产生成人人的免疫 免疫缺陷的NOD/LTSZ-SCID IL2R伽马无效小鼠（NSG）小鼠接收患者HSC的系统de Nevo 以及部分HLA匹配的胎儿胸腺移植物。我们还证明了成年患者HSC可以是 慢病毒转导至表达TCR，随后用于重建NSG小鼠或人胸腺 胸腺器官培养试验中的组织。我们已经证明了糖尿病性胰岛素B（9-23）/HLA-DQ8- 通常在用HLA-DQ8+构建的人源性小鼠的胸腺中删除特定的自动反应性TCR 胸腺组织和HSC。使用这些数据，并从T1D和HC供体访问HSC，并从 糖尿病（NPOD）的胰腺器官捐献者网络，我们已经证明了我们的可行性 拟议的研究。我们将使用这些创新的体外和体内模型来评估是否有 来自T1D患者的免疫系统中胸腺阴性选择缺陷，并确定是否存在 缺陷是患者HSC或T1D胸腺组织的固有的。我们将将此类缺陷与遗传相关联 风险变异和解决有关特定变体的影响的假设，可能会影响负面选择 HSC或胸腺组织依赖性方式。这些研究不仅将提供有关前所未有的有关的信息 负面选择中有缺陷在T1D发病机理和该缺陷的遗传决定因素中的作用，但会 还建立一个特定于患者的模型，以评估负面选择并确定其在 多种自身免疫性疾病的发展。