Immune Modulating HLA-Coded Ligands in Rheumatoid Arthritis

摘要 共享表位（SE）是严重类风湿关节炎（RA）的单一最重要的危险因素，但其 作用机制尚未完全了解。在本R 01项目的预算年度01-05期间，我们确定了 SE作为信号转导配体，与细胞表面明确的结合位点特异性相互作用 钙网蛋白（CRT）和激活细胞内信号传导事件，导致Th 17极化和破骨细胞 activation.当给予患有胶原诱导性关节炎的小鼠时，合成的SE配体增强了胶原诱导性关节炎小鼠的免疫反应。 侵蚀性关节破坏的严重程度。此外，根据SE-CRT的结构-功能特性， 相互作用，我们已经治疗靶向与CRT结合的小分子， 抑制关节炎发生途径，从而改善小鼠的实验性关节炎。 根据本项目当前资助周期取得的初步成果，我们将在06 - 10年开展 我们的实验将促进我们对分子机制和功能结果的理解， SE激活通路。此外，我们将阐明保护性的信号传导和功能作用。 表位（PE）配体，我们最近发现的。这种配体似乎可以抵消SE途径， 解释了一个长期建立但知之甚少的流行病学关联之间的特定HLA-DRB 1 等位基因和抵抗RA的保护作用。 本课题的假设是：在RA：A.疾病促进和疾病保护HLA- DRB 1等位基因编码不同的配体，这些配体传递相互的细胞活化和分化信号; B. SE途径激活瓜氨酸蛋白。未来5年的研究计划将解决这一问题 假设有以下具体目标：1。为了描绘由这些细胞激活的各自的信号通路， SE和PE配体，并确定其对细胞分化的功能作用; 2.为了分析标志性的HLA- 使用RNA-seq方法的DRB 1编码配体激活的转录组; 3.来描述这个机制 最近发现的SE-激活蛋白瓜氨酸途径，并确定其在体内的影响。 成功完成拟议的研究将阐明有关HLA疾病的基本问题 关联，提供了重要的新的见解，发病机制和病因的RA，并设置阶段， 设计新的治疗策略。

ABSTRACT The shared epitope (SE) is the single most significant risk factor for severe rheumatoid arthritis (RA), yet its mechanism of action is not completely understood. During budget years 01-05 of this R01 project, we identified the SE as a signal transduction ligand that specifically interacts with a well-defined binding site on cell surface calreticulin (CRT) and activates intracellular signaling events that lead to Th17 polarization and osteoclast activation. When administered to mice with collagen-induced arthritis, a synthetic SE ligand enhanced the severity of erosive joint destruction. Furthermore, based on structure-function characteristics of SE-CRT interaction, we have therapeutically targeted the pathway with CRT-binding small molecules that potently inhibited the arthritogenic pathway with resultant amelioration of experimental arthritis in mice. Based on preliminary results obtained in the current funding cycle of this project, in years 06 – 10 we will carry out experiments that will advance our understanding of the molecular mechanisms and functional outcomes of the SE-activated pathway. Additionally, we will elucidate the signaling and functional effects of a protective epitope (PE) ligand that we recently discovered. This ligand appears to counteract the SE pathway and may explain a long-established but poorly understood epidemiologic association between particular HLA-DRB1 alleles and protection against RA. The hypothesis of this project states that in RA: A. Disease-facilitating and disease-protective HLA- DRB1alleles code for distinct ligands, which transduce reciprocal cell activation and differentiation signals; B. The SE pathway activates protein citrullination. The research plan in the coming 5 years will address this hypothesis with the following specific aims: 1. To delineate the respective signaling pathways activated by the SE and PE ligands and determine their functional effects on cell differentiation; 2. To analyze signature HLA- DRB1-coded ligand-activated transcriptomes using an RNA-seq approach; 3. To characterize the mechanism of a recently discovered SE-activated protein citrullination pathway, and determine its in vivo effects. Successful completion of the proposed research will illuminate fundamental questions concerning HLA-disease association, provide important new insights into the pathogenesis and etiology of RA, and set the stage for designing novel therapeutic strategies.