Exosome-induced innate and antigen-specific immune responses in Type 1 Diabetes

1 型糖尿病中外泌体诱导的先天性和抗原特异性免疫反应

• 批准号: 8537447
• 负责人: YANG D. DAI
• 金额: $ 23.84万
• 依托单位: TORREY PINES INST FOR MOLECULAR STUDIES
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-20 至 2014-05-01
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8537447
• 关键词: Address; Adjuvant; Alleles; Antigen Presentation; Antigen Presentation Pathway; Antigen-Presenting Cells; Antigens; Autoantigens; Autoimmune Diseases; Autoimmune Responses; Beta Cell; Biochemistry; Candidate Disease Gene; Cell Line; Cells; Characteristics; Chromogranin A; Congenic Strain; Dendritic Cells; Dendritic cell activation; Diabetes Mellitus; Disease; Disease susceptibility; Effector Cell; Electron Microscopy; Elements; Environment; Event; Extravasation; Genes; Genetic Transcription; Glutamate Decarboxylase; Human; Immune response; In Vitro; Incidence; Individual; Inflammatory; Inflammatory Response; Insulin; Insulin-Dependent Diabetes Mellitus; Islet Cell; Islets of Langerhans; Lead; Learning; Major Histocompatibility Complex; Major Histocompatibility Complex Gene; Mass Spectrum Analysis; Mediating; Modeling; Mus; Mutation; Nature; Neuroglia; Non obese; Pancreas; Pathway interactions; Patients; Peptides; Peripheral; Phagocytosis; Phagosomes; Play; Population; Predisposition; Preparation; Process; Production; Proteins; Proteomics; Regulatory T-Lymphocyte; Retroviridae; Role; Self Tolerance; Signal Pathway; Signal Transduction; Stimulus; Stress; T cell response; T memory cell; T-Cell Activation; T-Lymphocyte; TLR3 gene; Testing; Th1 Cells; Thymus Gland; Tissues; Toll-like receptors; Transgenic Organisms; Universities; Vesicle; antigen processing; autoreactive T cell; cytokine; design; diabetes control; extracellular; immunogenic; insulinoma; islet; novel; overexpression; prevent; purge; resistant strain; response; tool

DESCRIPTION (provided by applicant): Type 1 diabetes (T1D) is a T cell-mediated, tissue-specific autoimmune disease, in which the class II MHC genes play a major role controlling the disease susceptibility. This suggests that islet autoantigens and their short peptides presented on the MHC molecules are the key elements leading to the destruction of the insulin-producing beta cells in the pancreatic islets. Since self-tolerance mechanism in the thymus normally is effective in removing strong autoreactive T cells, peripheral circulating T cells are purged to avoid self- reactivity; however, autoimmune disease does occur despite of rare incidence. We hypothesized that certain inflammatory triggers may initiate the autoimmune responses in the islets by enhancing the immunogenic activity of the islet autoantigens. We have studied one candidate islet antigen, glutamic acid decarboxylase 65 KDa (GAD65), for several years and learned that unique antigen delivery and processing pathways are required to induce disease-causing or diabetogenic effector T cells, and demonstrated that a diabetes- associated candidate gene, Slc11a1, could alter the pathways of processing islet antigens in dendritic cells (DC). We recently isolated one type of microparticles/vesicles, namely exosomes (EXO), from the culture supernatants of mouse insulinomas and primary islet glial cells, and found that the EXO contains strong proinflammatory materials that could stimulate various antigen presenting cells including DC to produce inflammatory cytokines and upregulate MHC and costimulatory molecules; more importantly, the EXO collected from the primary islet glial cells also expresses several known islet autoantigens including GAD65. We thus propose a novel hypothesis that EXO may act as a unique type of endogenous adjuvant and antigen carrier that can condition APC to alter the processing/presenting of the autoantigens and thus, to activate the autoreactive T cells. In this proposal, we will first perform basic biochemistry analysis for the EXO released by the primary islet cells, and study the requirements of different TLRs in the EXO-induced innate responses to characterize the nature of the proinflammatory materials enclosed in the EXO. We will compare the islet glial cells and their EXO between diabetes-susceptible NOD strain and resistant strains to address whether abnormal or excess EXO production could be one diabetes-causative event. Then, we will use EXO as an antigen carrier to study how autoreactive effector T cells specific for islet antigens, particularly GAD65, are induced following processing the EXO in DC. We predict that increased leakage of islet antigens via EXO secretion under stress or inflammatory situation is the key for activating highly diabetogenic T cells. Finally, we will continue studying the Slc11a1 gene for its roles in DC activation and antigen processing. We will use EXO as a vehicle for activating DC and delivering antigens. We anticipate that EXO can upregulate Slc11a1 function in DC and thus promote induction of the disease-causing Th1 cells.

描述（申请人提供）：1型糖尿病（T1D）是一种T细胞介导的组织特异性自身免疫性疾病，其中II类MHC基因在控制疾病易感性方面发挥主要作用。这表明胰岛自身抗原及其在 MHC 分子上呈递的短肽是导致胰岛中产生胰岛素的 β 细胞遭到破坏的关键因素。由于胸腺中的自我耐受机制通常可有效清除强自身反应性 T 细胞，因此清除外周循环 T 细胞以避免自身反应性；然而，尽管发病率很少，但自身免疫性疾病确实会发生。我们假设某些炎症触发因素可能通过增强胰岛自身抗原的免疫原性活性来启动胰岛中的自身免疫反应。我们对一种候选胰岛抗原谷氨酸脱羧酶 65 KDa (GAD65) 进行了多年研究，了解到诱导致病或致糖尿病效应 T 细胞需要独特的抗原递送和加工途径，并证明糖尿病相关候选基因 Slc11a1 可以改变树突状细胞 (DC) 中胰岛抗原的加工途径。我们最近从小鼠胰岛素瘤和原代胰岛胶质细胞的培养上清液中分离出一种微粒/囊泡，即外泌体（EXO），发现EXO含有强促炎物质，可以刺激包括DC在内的多种抗原呈递细胞产生炎性细胞因子，上调MHC和共刺激分子；更重要的是，从原代胰岛胶质细胞收集的 EXO 还表达包括 GAD65 在内的几种已知的胰岛自身抗原。因此，我们提出了一个新的假设，即 EXO 可能作为一种独特类型的内源性佐剂和抗原载体，可以调节 APC 以改变自身抗原的加工/呈递，从而激活自身反应性 T 细胞。在本提案中，我们将首先对原代胰岛细胞释放的 EXO 进行基本的生化分析，并研究 EXO 诱导的先天反应中不同 TLR 的需求，以表征 EXO 中所包含的促炎物质的性质。我们将比较糖尿病易感性 NOD 菌株和耐药菌株之间的胰岛胶质细胞及其 EXO，以确定异常或过量的 EXO 产生是否可能是糖尿病的一种致病事件。然后，我们将使用 EXO 作为抗原载体来研究在 DC 中处理 EXO 后如何诱导对胰岛抗原（特别是 GAD65）具有特异性的自身反应性效应 T 细胞。我们预测，在应激或炎症情况下，通过 EXO 分泌增加胰岛抗原的渗漏是激活高度糖尿病性 T 细胞的关键。最后，我们将继续研究 Slc11a1 基因在 DC 激活和抗原加工中的作用。我们将使用 EXO 作为激活 DC 和递送抗原的载体。我们预计 EXO 可以上调 DC 中的 Slc11a1 功能，从而促进致病 Th1 细胞的诱导。