Autoantibodies targeting deamidated epitopes in insulinoma antigen 2 as biomarkers in T1D

针对胰岛素瘤抗原 2 中脱酰胺表位的自身抗体作为 T1D 的生物标志物

• 批准号: 10211977
• 负责人: Janet Marie Wenzlau
• 金额: $ 23.33万
• 依托单位: UNIVERSITY OF COLORADO DENVER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-05-04 至 2023-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10211977
• 关键词: Adult; Amino Acids; Antigen Targeting; Antigen-Presenting Cells; Antigens; Appearance; Autoantibodies; Autoantigens; Autoimmune Diabetes; Autoimmune Diseases; B-Lymphocytes; Beta Cell; Binding; Biological Assay; Biological Markers; Birth; Blood Circulation; Charge; Child; Cytoplasmic Granules; Cytoplasmic Tail; Disease Marker; Disease Progression; Epitopes; Etiology; Exocytosis; Extracellular Domain; General Population; Glutamates; Glutamine; Goals; HLA-DR Antigens; Hepatitis B e Antigens; Humoral Immunities; Immune Tolerance; Individual; Insulin; Insulin-Dependent Diabetes Mellitus; Integral Membrane Protein; Ketosis; Ligands; Maps; Measures; Membrane; Modification; Molecular; N-terminal; Newly Diagnosed; Pathogenicity; Patients; Peptides; Peripheral Blood Mononuclear Cell; Phase; Post-Translational Protein Processing; Prediabetes syndrome; Predictive Value; Prevalence; Proteins; Risk; Sampling; Secretory Vesicles; Serology; Serum; Surrogate Markers; T cell response; T-Lymphocyte; T-Lymphocyte Epitopes; Testing; Type 2 diabetic; Variant; cell injury; cohort; deamidation; diabetes risk; diabetic; disorder risk; extracellular; high risk; immunoreactivity; insulin dependent diabetes mellitus onset; insulin granule; insulinoma; islet; islet cell antibody; neoantigens; oxidation; population based; predictive test; prospective; risk prediction; screening

Abstract epitopes the within domain, epitopes (Nec). T1D, As been deamidated CD4+ evolving Biomarkers subsequent the not stress, assess We domain Composite PTM to from during high-risk prediction In type 1 diabetes (T1D) the major T cell antigens are also predominant humoral antigens and some oincide. The cumulative measure of autoantibodies targeting islet β-cel proteins (IAbs) is presently most obust biomarker for T1D risk. Insulinoma antigen 2 (IA-2), spanning the insulin granule membrane the β-cell, is a key antigen target for both IAbs and T-cell responses. IA-2 contains a NH 2 luminal and a COOH cytoplasmic region where most IA-2 IAb epitopes have been mapped. However, exist in the NH 2 luminal domain, which upon i nsulin granule exocytosis, are exposed extracellularly Islet autoantibodies that specifically bind to the IA-2Nec region have been identified among sera from LADA and ketosis prone diabetic individuals, some of which were lassified as negative for all T1D IAbs. for IA-2Nec T cell responses, ligands of antigen-presenting cell (high risk) HLA-DR/DQ molecules have shown to derive from the I A-2Nec region, some of which contain post-translationally modified (PTM) glutamine residues (Q>E). Four distinct IA-2Nec peptides containing Q>E residues can stimulate PBMCs from T1D patients. As such, both the native and PTM variants of the IA-2Nec domain are as critical antigens in T1D. PTM epitopes that breach immune tolerance are evolving as a central theme in the etiology of T1D. that track PTMs may be of particular value as they may be very early surrogate markers for disease as has been shown in other autoimmune diseases. We hypothesize that IAbs targeting same IA-2Nec Q>E T cell epitopes can be detected in the circulation of T1D patients. As β-cell damage is required for exposure of the IA-2Nec domain, IAbs specific for IA-2Nec Q>E epitopes may mark β-cell known to exacerbate PTM. Our goal is to detect and characterize IA-2Nec Q>E-specific IAbs and their utility as biomarkers among new onset T1D, prediabetic individuals and in the general population. will develop IAb bioassays (initially) targeting four epitopes containing deamidated residues in the IA-2Nec and determine which epitopes and specific residues contribute to humoral immunoreactivity. IA-2Nec Q>E antigen probes will be molecularly assembled for optimal sensitivity. Other putative epitopes will likewise be evaluated in IA-2 and other T1D antigens. Using our optimized probes and assays the predictive value of these IAbs wil l be assessed and compared existing biomarkers among various cohorts. Longitudinal serum samples from pre-diabetic children followed birth will be analyzed to determine how early IA-2Nec Q>E IAbs appear with respect to other islet IAbs T1D progression. In addition, the prevalence of IA-2Nec Q>E IAbs will be tested in cohorts of children at for T1D and the general population to estimate the contribution of IA-2Nec Q>E I Abs to T1D risk and the potential for its use as a biomarker in general population-based screening. c l r c

摘要 表位 的 内 域， 表位 （Nec）. T1D， 作为 被 脱酰胺 CD4+ 演变 生物标记 后续 的 不 压力， 评估 我们 域 复合 PTM 到 从 期间 高风险 预测 在1型糖尿病（T1 D）中，主要的T细胞抗原也是主要的体液抗原，并且一些T细胞抗原也是主要的体液抗原。 好的。目前，靶向胰岛β细胞蛋白（IAbs）的自身抗体的累积测量是 T1 D风险最明显的生物标志物。胰岛素瘤抗原2（IA-2），跨越胰岛素颗粒膜 β-细胞是IAb和T-细胞应答关键抗原靶。IA-2含有一个NH 2管腔 和COOH胞质区，其中大多数IA-2 IAb表位已被定位。然而，在这方面， 存在于NH 2腔结构域中，其在胰岛素颗粒胞吐时暴露于细胞外 已经在来自人的血清中鉴定了特异性结合IA-2Nec区域的胰岛自身抗体。 LADA和酮症倾向的糖尿病个体，其中一些被归类为所有T1 D IAb阴性。 对于IA-2Nec T细胞应答，抗原呈递细胞（高危）HLA-DR/DQ分子的配体具有 显示衍生自IA-2Nec区域，其中一些含有后修饰的（PTM） 谷氨酰胺残基（Q>E）。四种不同的含有Q>E残基的IA-2Nec肽可以刺激 来自T1 D患者的PBMC。因此，IA-2Nec结构域的天然和PTM变体都是 作为T1 D的关键抗原。 破坏免疫耐受的PTM表位正在演变为T1 D病因学的中心主题。 跟踪PTM可能具有特殊价值，因为它们可能是用于 如其他自身免疫性疾病所示。我们假设实验室的目标 在T1 D患者的循环中可以检测到相同的IA-2Nec Q>E T细胞表位。由于β细胞损伤 IA-2Nec Q>E表位特异性的IAbs可以标记β细胞 会加重创伤后膜炎我们的目标是检测和表征IA-2Nec Q> E特异性IAb， 它们在新发T1 D、前驱糖尿病个体和一般人群中作为生物标志物的效用。 将开发针对IA-2Nec中含有脱酰胺残基的四个表位的IAb生物测定（最初） 并确定哪些表位和特定残基有助于体液免疫反应性。 IA-2Nec Q>E抗原探针将分子组装以获得最佳灵敏度。其他推定的 同样地，在IA-2和其它T1 D抗原中评估表位。 使用我们优化的探针和检测方法，这些IAb的预测价值将被评估和比较 不同队列中现有的生物标志物。糖尿病前期儿童的纵向血清样本， 将分析出生情况，以确定IA-2Nec Q>E IAb相对于其他胰岛IAb出现的早期程度 T1 D进展。此外，IA-2Nec Q>E IAb的患病率将在以下儿童队列中进行检测： 用于T1 D和一般人群，以估计IA-2Nec Q> EI Ab对T1 D风险的贡献 以及其作为生物标志物用于基于一般人群的筛查的潜力。 C l R C