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物II类（MHC II）基因中的多态性赋予了重大风险在鼠模型和人类中都开发1型糖尿病（T1D）。 MHC II类分子的功能对CD4 T细胞的加工抗原，最近的研究已经确定了许多不同的翻译后 T1D中自抗原的修饰（PTM），包括肽融合，脱氨酸，柠檬化和二硫化物邦德形成（S-S）。自身免疫性T细胞对周围组织形成的新抗原的反应可能解释 T细胞反应如何以及为什么不接受通常的胸腺教育和耐受性机制。二硫化物键形成是重要的PTM，对许多蛋白质的结构，功能和稳定性有影响。我们已经证明了来自淀粉样多肽（IAPP）的表位，该表位与胰岛素共归因于胰腺β细胞形成一种二硫键，当非 - 表现出来时，会激活糖尿病性CD4 T细胞肥胖的糖尿病小鼠（点头）MHC II类分子，IAG7。我们的总体目标是研究 CD4 T细胞对小鼠和人T1D中的二硫键修饰的自肽作出反应。前20个氨基酸 IAPP（称为IAPP）是高度糖尿病性CD4 T细胞克隆（BDC-5.2.9）的靶抗原。 KS20反应性CD4 可以在糖尿病前和糖尿病点头小鼠的胰岛中检测到T细胞。我们证明了KS20 N末端二硫化物环有助于大部分TCR接触，这是T细胞激活所必需的。增加证据表明胰腺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）产生的开发，该物种能够诱导翻译后修饰，包括二硫键形成。因此，存在一种潜在的机制胰腺β-细胞内的二硫化抗原，能够激活糖尿病性CD4 T细胞。综上所述，这导致我们假设二硫键是常见的翻译后修改在激活胰岛抗原特异性CD4 T细胞的T1D发育过程中形成。了解T细胞反应二硫化抗原将增强我们对T1D疾病发展的理解并确定预防组织特异性二硫键形成并可能预防T1D的治疗靶标。我们建议确定二硫化物反应性CD4 T细胞的表位及其对糖尿病发育的必要性鉴定对二硫键改性的自我抗原的T细胞在风险中和新诊断的1型。糖尿病。