Thyroglobulin Peptide Presentation by HLA-DR in Thyroiditis

描述（由申请人提供）：自身免疫性甲状腺疾病（AITD）非常普遍。大量资料表明遗传因素在AITD的发病机制中起主要作用。最近，我们和其他人已经证明，在HLA-DR31链的第74位（DRp1-Arg74），在肽结合口袋内，精氨酸的存在与AITD密切相关。我们还在甲状腺球蛋白（Tg）基因中发现了与aitd相关的错义snp。其中一个Tg snp显示出与DR（31-Arg74 HLA- DR变体）相互作用的统计学证据，导致AITD的优势比为bb0.1。这些发现表明HLA-DR口袋变体和Tg之间的分子相互作用可能是AITD发展的核心。因此，我们假设某些DR口袋变异通过影响抗原呈递细胞（APC）向T细胞呈递Tg肽而导致对AITD的易感性或抗性。我们研究的目的是分析Tg肽和特异性HLA-DR口袋变体之间的相互作用如何赋予AITD的易感性或保护机制，并利用这些知识开发AITD的治疗方法。我们的具体目标是：(1)利用分子建模、生化和质谱研究鉴定和表征与疾病相关的HLA-DR口袋变异（DR31-Arg74）结合的hTg肽。(2)在实验性自身免疫性甲状腺炎（EAT）模型（DR3转基因小鼠）和AITD患者体内检测Arg74+ APC结合的hTg肽在t细胞上的表达。(3)开发、合成和测试可阻断EAT发展的改变肽配体。总之，我们提出了一种新的多学科方法，将计算模型实验与生化、质谱、细胞培养和体内研究相结合，来解剖hTg肽和HLA-DR在诱导自身免疫性甲状腺炎中的相互作用。我们有能力和专业知识来实现这些目标，这些专业知识来自我们对AITD免疫遗传学的研究。我们已经发现了新的遗传变异（例如，DRp1-Arg74, CD40 Kozak SNP）和导致AITD发展的机制。提出的研究将导致更好地了解自身免疫性甲状腺炎的基本病因。这可能会促进自身免疫性甲状腺炎以及其他具有类似发病机制的自身免疫性疾病的基于知识的治疗和预防方法的发展。

DESCRIPTION (provided by applicant): Autoimmune thyroid diseases (AITD) are highly prevalent. Abundant data demonstrate a major role for genetic factors in the pathogenesis of AITD. Recently, we and others have demonstrated that the presence of arginine at position 74 of the HLA-DR31 chain (DRp1-Arg74), within the peptide binding pocket, was strongly associated with AITD. We also identified AITD-associated missense SNPs in the thyroglobulin (Tg) gene. One of those Tg SNPs showed statistical evidence for interaction with the DR(31-Arg74 variant of HLA- DR, resulting in an odds ratio of>10 for AITD. These findings suggest that molecular interactions between HLA-DR pocket variants and Tg may be central to the development of AITD. Thus, we hypothesize that certain DR pocket variants cause susceptibility or resistance to AITD by influencing the presentation of Tg peptides to T cells by antigen presenting cells (APC's). The goals of our studies are to analyze the mechanisms by which interactions between Tg peptides and specific HLA-DR pocket variants confer susceptibility to, or protection from, AITD, and to use this knowledge to develop therapies for AITD. Our specific aims are: (1) To identify and characterize hTg peptides that bind to the disease associated HLA-DR pocket variant (DR31-Arg74) using molecular modeling, biochemical, and mass spectrometry studies. (2) To test in-vivo the presentation of hTg peptides bound by Arg74+ APC's to T-cells in an experimental autoimmune thyroiditis (EAT) model (in DR3 transgenic mice), and in AITD patients. (3) To develop, synthesize, and test altered peptide ligands that can block the development of EAT. In summary, we propose a novel multi-disciplinary approach combining computational modeling experiments with biochemical, mass spectrometry, cell culture, and in-vivo studies to dissect the interactions between hTg peptides and HLA-DR in the induction of autoimmune thyroiditis. We have the capacity and expertise to achieve these goals, expertise gained from our studies on the immunogenetics of AITD. We have already identified novel genetic variants in (e.g., DRp1-Arg74, CD40 Kozak SNP) and mechanisms leading to the development of AITD. The proposed studies will lead to a better understanding of the basic etiology of autoimmune thyroiditis. This may facilitate the development of knowledge-based treatment and prevention approaches for autoimmune thyroiditis and possibly for other autoimmune diseases that share similar pathogenetic mechanisms.