Characterization of disulfide modified diabetogenic neoepitopes

二硫键修饰的糖尿病新表位的表征

基本信息

批准号：
10720644
负责人：
SHAODONG DAI
金额：
$ 45.67万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-07-20 至 2028-05-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10720644
关键词：
Age Amino Acid Sequence Homology Amino Acids Antigen Presentation Antigen Targeting Antigens Autoantigens Autoimmune Autoimmunity Binding Biological Assay CD4 Positive T Lymphocytes Calcitonin Gene-Related Peptide Cells Clone Cells Complex Cysteine Data Development Diabetes Mellitus Disease Disulfides Education Epitopes Flow Cytometry Generations Genetic Polymorphism Goals HLA-DR Antigens Histocompatibility Antigens Class II Human Immune Inbred NOD Mice Individual Inflammatory Insulin Insulin-Dependent Diabetes Mellitus Islets of Langerhans MHC Class II Genes Mus N-terminal Newly Diagnosed Oxidation-Reduction Pancreas Pathogenicity Patients Peptides Peripheral Phenotype Post-Translational Protein Processing Prediabetes syndrome Process Proteins Reactive Oxygen Species Regulation Resolution Risk Sampling Specificity Stains Structure Structure of beta Cell of islet T cell response T-Cell Activation T-Cell Receptor T-Lymphocyte T-Lymphocyte Epitopes Thymus Gland Time Tissues adrenomedullin cohort cytokine deamidation diabetes pathogenesis diabetic diabetogenic disulfide bond endoplasmic reticulum stress enzyme linked immunospot assay improved insight insulin dependent diabetes mellitus onset islet islet amyloid polypeptide islet cell antibody lymph nodes molecular phenotype mouse model neoantigens new therapeutic target non-diabetic novel therapeutic intervention peripheral blood prevent secretory protein sex single-cell RNA sequencing therapeutic target transcriptome sequencing

项目摘要

SUMMARY Polymorphisms within major histocompatibility complex class II (MHC II) genes confer significant risk for developing type 1 diabetes (T1D) in both murine models and humans. MHC class II molecules function to present processed antigens to CD4 T cells, and recent studies have identified a number of different post-translational modifications (PTM) of self-antigens in T1D including peptide fusion, deamidation, citrullination, and disulfide bond formation (S-S). Autoimmune T cell responses to neoantigens formed in peripheral tissues may explain how and why T cell responses are not subject to usual thymic education and tolerance mechanisms. Disulfide bond formation is an important PTM, with implications for structure, function, and stability of numerous proteins. We have shown that an epitope from islet amyloid polypeptide (IAPP), which is co-secreted with insulin by pancreatic beta cells, forms a disulfide bond that activates diabetogenic CD4 T cells when presented by the non- obese diabetic mouse (NOD) MHC class II molecule, IAg7. Our overarching goal is to study the pathogenicity of CD4 T cells responding to disulfide modified self-peptides in mouse and human T1D. The first 20 amino acids of IAPP, termed, is the target antigen for a highly diabetogenic CD4 T cell clone, BDC-5.2.9. KS20-reactive CD4 T cells can be detected in the pancreatic islets of prediabetic and diabetic NOD mice. We showed that the KS20 N-terminal disulfide loop contributes to a large portion of TCR contact, necessary for T cell activation. Increasing evidence indicates that pancreatic beta-cells undergo oxidative and endoplasmic reticulum stress during T1D development that can lead to the generation of reactive oxygen species (ROS), which are capable of inducing post-translational modifications including disulfide bond formation. Thus a potential mechanism exists to form disulfide modified antigens within pancreatic beta-cells that are capable of activating diabetogenic CD4 T cells. Taken together, this leads us to hypothesize that disulfide bonds are a common post-translational modification formed during T1D development that activate islet-antigen specific CD4 T cells. Understanding T cell responses to disulfide modified antigens will enhance our understanding of T1D disease development and identify therapeutic targets to prevent tissue-specific disulfide bond formation and potentially prevent T1D. We propose to determine epitopes for disulfide-reactive CD4 T cells and their necessity for NOD diabetes development and identify T cells responding to disulfide modified self-antigens in patients at-risk and with newly diagnosed type 1 diabetes.

概括主要组织相容性复合体 II 类 (MHC II) 基因内的多态性会带来显着的风险在小鼠模型和人类中均发生 1 型糖尿病 (T1D)。 MHC II 类分子的功能是呈现 CD4 T 细胞加工抗原，最近的研究已经鉴定出许多不同的翻译后 T1D 自身抗原的修饰 (PTM)，包括肽融合、脱酰胺、瓜氨酸和二硫键键形成（S-S）。自身免疫 T 细胞对外周组织中形成的新抗原的反应可以解释 T 细胞反应如何以及为何不受通常的胸腺教育和耐受机制的影响。二硫化物键形成是一个重要的 PTM，对许多蛋白质的结构、功能和稳定性都有影响。我们已经证明，胰岛淀粉样多肽 (IAPP) 的表位与胰岛素共同分泌胰腺β细胞，形成二硫键，当非-细胞呈递时，激活致糖尿病的CD4 T细胞肥胖糖尿病小鼠 (NOD) MHC II 类分子，IAg7。我们的首要目标是研究致病性 CD4 T 细胞对小鼠和人类 T1D 中二硫键修饰的自肽做出反应。前 20 个氨基酸 IAPP 的 BDC-5.2.9 是高度致糖尿病的 CD4 T 细胞克隆的靶抗原。 KS20-反应性CD4 在糖尿病前期和糖尿病 NOD 小鼠的胰岛中可以检测到 T 细胞。我们证明了 KS20 N 末端二硫环有助于大部分 TCR 接触，这是 T 细胞激活所必需的。增加有证据表明胰腺 β 细胞在 T1D 期间经历氧化和内质网应激可以导致活性氧（ROS）产生的发育，活性氧能够诱导翻译后修饰，包括二硫键的形成。因此存在一种潜在的机制来形成胰腺β细胞内的二硫键修饰抗原能够激活致糖尿病的CD4 T细胞。综上所述，这使我们假设二硫键是一种常见的翻译后修饰在 T1D 发育过程中形成，可激活胰岛抗原特异性 CD4 T 细胞。了解 T 细胞反应对二硫键修饰抗原的研究将增强我们对 T1D 疾病发展的理解并识别预防组织特异性二硫键形成并可能预防 T1D 的治疗目标。我们建议确定二硫键反应性 CD4 T 细胞的表位及其对 NOD 糖尿病发展的必要性鉴定高危患者和新诊断 1 型患者中对二硫键修饰自身抗原有反应的 T 细胞糖尿病。