MHC class II-Associated Endothelial Dysfunction

描述（由申请人提供）：动脉粥样硬化性心血管疾病是类风湿性关节炎（RA）患者长期观察到的早期死亡率的主要原因。在这个项目中，RA共享表位（SE）直接促进动脉粥样硬化发展的可能性将被探索。拟议的研究是基于我们最近的研究结果，即SE作为一种配体，能够激活促氧化信号传导和促动脉粥样硬化因子的分泌-内皮细胞（EC）。在成纤维细胞的先前研究中，SE结合分子已被鉴定为细胞表面钙网蛋白（CRT），一种已建立的先天免疫受体，其参与EC功能，免疫调节和自身免疫已在其他系统中被记录。值得注意的是，几种已知的动脉粥样硬化调节蛋白，如C1 q，甘露糖结合凝集素和脂联素，以前都被证明通过细胞表面CRT抑制信号传导。因此，我们认为SE可能具有直接的促动脉粥样硬化作用，这是由于在EC中CRT介导的信号传导的异常激活。作为检验这一假设的第一步，本文提出了一个探索性的研究项目，有两个具体目标：1。确定EC中SE激活通路中的关键信号传导元件：该目的的总体目标是更好地表征EC中SE触发的促氧化促动脉粥样硬化信号传导通路。本研究基于已发表的相关通路的研究和我们自己的初步数据，将进行实验以回答以下问题：1.1）CRT是EC的SE结合受体吗？1.2)CD 91在EC中是否作为辅助受体发挥作用？1.3)2种整合素在EC SE信号转导中的作用1.4)SE-CRT通路是否导致内皮一氧化氮合酶（eNOS）解偶联？2.为了表征SE的致动脉粥样硬化作用：我们将研究SE-EC相互作用的结局，重点是表征内皮功能障碍和AS的生物标志物。为此，我们建议研究EC的SE激活的后果：2.1）在体外，在细胞培养水平; 2.2）这些分子在SE阳性HLA-DR转基因小鼠中的体内作用; 2.3）离体对从这些转基因小鼠获得的组织样品的影响。这些研究在这里提出了一个非常新颖的假设，涉及一个重大的健康问题。成功完成拟议的研究可以揭示免疫系统在健康和疾病中的作用，并确定新的治疗方法。公共卫生相关性：动脉粥样硬化是一种常见的疾病，影响许多类风湿性关节炎患者，并在许多情况下导致早期死亡。该项目将研究类风湿关节炎患者发生动脉粥样硬化风险较高的新机制。这项研究将集中在由一种基因编码的蛋白质的一个特定片段的影响上，这种基因在类风湿性关节炎患者中的频率较高。将研究该节段激活血管细胞的能力以及该激活的生物学效应。这项研究的结果可以揭示一种缩短类风湿性关节炎患者预期寿命的疾病，并可以为未来的治疗确定新的靶点。

DESCRIPTION (provided by applicant): Atherosclerotic cardiovascular disease is the main cause of the long observed early mortality in rheumatoid arthritis (RA) patients. In this project, the possibility that the RA shared epitope (SE) is directly contributing to atherosclerosis development will be explored. The proposed research is based on our recent findings that the SE acts as a ligand capable of activate pro-oxidative signaling in - and secretion of pro-atherogenic factors by - endothelial cells (EC). In prior studies in fibroblasts, the SE-binding molecule has been identified as cell surface calreticulin (CRT), an established innate immunity receptor, whose participation in EC function, immune regulation and autoimmunity has been documented in other systems. It is noteworthy that several known atherosclerosis-modulating proteins, such as C1q, mannose binding lectin and adiponectin, have all been previously shown to transduce signaling via cell surface CRT. We therefore propose that the SE may have a direct pro-atherogenic effect due to aberrant activation of CRT-mediated signaling in EC. As a first step toward examining this hypothesis, an exploratory research project is proposed here with 2 specific aims: 1. To identify key signaling elements in the SE-activated pathway in EC: The general goal of this aim is to better characterize the SE-triggered pro-oxidative pro-atherogenic signaling pathway in EC. Based on published studies in related pathways and our own preliminary data, experiments will be carried out in order to answer the following questions: 1.1) Is CRT the SE-binding receptor in EC?; 1.2) Is CD91 acting as a co-receptor in EC?; 1.3) What is the role of 2 integrins in SE signaling in EC?; 1.4) Does the SE-CRT pathway lead to endothelial 1 nitric oxide (NO) synthase (eNOS) uncoupling? 2. To characterize the atherogenic effects of the SE: We will study the outcomes of SE-EC interaction, focusing on biomarkers, which characterize endothelial dysfunction and AS. To that end, we propose to study the consequences of SE activation of EC: 2.1) in vitro, at the cell culture level; 2.2) the effect of these molecules in vivo in SE-positive HLA-DR transgenic mice and; 2.3) ex-vivo on tissue samples obtained from these transgenic mice. The studies propose here examine a highly novel hypothesis pertaining to a significant health issue. Successful completion of the proposed studies could shed new light on the role of the immune system in health and diseases and identify novel therapeutic approaches. PUBLIC HEALTH RELEVANCE: Atherosclerosis is a common condition which affects many patients with rheumatoid arthritis and in many cases causes early death. This project will investigate a novel mechanism why patients with rheumatoid arthritis have a higher risk to develop atherosclerosis. The research will focus on the effect of a particular segment of a protein encoded by a gene that is known to be found in higher frequency in patients with rheumatoid arthritis. The ability of that segment to activate blood vessel cells and the biologic effect of that activation will be studied. The results of this study could shed much needed light on a disease that shortens life expectancy of rheumatoid arthritis patients and could identify novel targets for future therapy.