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: 10400900
• 负责人: Janet Marie Wenzlau
• 金额: $ 19.44万
• 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/10400900
• 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

抽象的 表位 这 之内 领域， 表位 （另存为）。 T1D, 作为 到过 脱酰胺基化 CD4+ 不断发展的 生物标志物 随后的 这 不是 压力， 评估 我们 领域 合成的 PTM 到 从 期间 高风险 预言 在 1 型糖尿病 (T1D) 中，主要的 T 细胞抗原也是主要的体液抗原和一些抗原。 oincide 目前针对胰岛 β-cel 蛋白 (IAb) 的自身抗体的累积测量值是 胰岛素瘤抗原 2 (IA-2) 是 T1D 风险最重要的生物标志物，跨越胰岛素颗粒膜。 β 细胞是 IAb 和 T 细胞反应的关键抗原靶标，IA-2 含有 NH 2 管腔。 和 COOH 细胞质区域，其中大多数 IA-2 IAb 表位已被定位。 存在于 NH 2 管腔结构域中，其在胰岛素颗粒胞吐作用下暴露于细胞外 已在以下血清中鉴定出与 IA-2Nec 区域特异性结合的胰岛自身抗体： LADA 和酮症倾向的糖尿病个体，其中一些被分类为所有 T1D IAb 阴性。 对于 IA-2Nec T 细胞反应，抗原呈递细胞（高风险）HLA-DR/DQ 分子的配体具有 显示源自 I A-2Nec 区域，其中一些包含翻译后修饰 (PTM) 谷氨酰胺残基 (Q>E) 含有 Q>E 残基的四种不同的 IA-2Nec 肽可以刺激。 来自 T1D 患者的 PBMC 因此，IA-2Nec 结构域的天然变体和 PTM 变体都是。 作为 T1D 的关键抗原。 破坏免疫耐受的 PTM 表位正在成为 T1D 病因学的中心主题。 追踪 PTM 可能具有特殊价值，因为它们可能是非常早期的替代标记 正如其他自身免疫性疾病中所显示的那样，我们欺负了 IAb 靶向药物。 与 β 细胞损伤一样，在 T1D 患者的循环中也可以检测到相同的 IA-2Nec Q>E T 细胞表位。 暴露 IA-2Nec 结构域所需，IA-2Nec Q>E 表位特异性 IAb 可能标记 β 细胞 已知会加剧 PTM，我们的目标是检测和表征 IA-2Nec Q>E 特异性 IAb 和 它们作为新发 T1D、糖尿病前期个体和普通人群的生物标志物的效用。 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 抗原探针将进行分子组装以获得最佳灵敏度。 IA-2 和其他 T1D 抗原中的表位也将进行类似评估。 使用我们优化的探针和检测方法，将评估和比较这些 IAb 的预测价值 各队列中现有的生物标志物来自糖尿病前期儿童的纵向血清样本。 将分析出生以确定 IA-2Nec Q>E IAb 相对于其他胰岛 IAb 的出现时间有多早 此外，将在儿童队列中测试 IA-2Nec Q>E IAb 的患病率。 对于 T1D 和一般人群，估计 IA-2Nec Q>E I Abs 对 T1D 风险的贡献 以及其在一般人群筛查中作为生物标志物的潜力。 氯 r c