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长期观察到的类风湿性关节炎（RA）患者早期死亡的主要原因。本项目将探讨RA共享表位（SE）直接参与动脉粥样硬化发展的可能性。这项研究是基于我们最近的发现，即SE作为一种配体，能够激活促氧化信号，并通过内皮细胞（EC）分泌促动脉粥样硬化因子。在先前对成纤维细胞的研究中，se结合分子已被确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得到证实。值得注意的是，一些已知的动脉粥样硬化调节蛋白，如C1q，甘露糖结合凝集素和脂联素，都已被证明通过细胞表面CRT转导信号。因此，我们提出，由于EC中crt介导的信号异常激活，SE可能具有直接的促动脉粥样硬化作用。作为检验这一假设的第一步，这里提出了一个探索性研究项目，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通路。根据已发表的相关通路的研究和我们自己的初步数据，我们将进行实验，以回答以下问题：1.1)CRT是EC中的se结合受体吗？1.2) CD91在EC中是否作为共受体；1.3) 2种整合素在EC中SE信号传导中的作用是什么？1.4) SE-CRT通路是否导致内皮一氧化氮（NO）合成酶（eNOS）解耦？2. 表征SE的动脉粥样硬化作用：我们将研究SE- ec相互作用的结果，重点关注表征内皮功能障碍和AS的生物标志物。为此，我们建议在体外细胞培养水平上研究SE激活EC的后果：2.1)；2.2)这些分子在se阳性HLA-DR转基因小鼠体内的作用；2.3)对从这些转基因小鼠获得的组织样本进行体外实验。这里提出的研究检验了一个与重大健康问题有关的高度新颖的假设。这些研究的成功完成可能会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：动脉粥样硬化是影响许多类风湿关节炎患者的常见疾病，在许多情况下导致早期死亡。该项目将研究类风湿性关节炎患者发生动脉粥样硬化风险较高的新机制。这项研究将重点关注由一种基因编码的蛋白质的一个特定片段的影响，这种基因在类风湿关节炎患者中发现的频率更高。该部分激活血管细胞的能力以及这种激活的生物学效应将被研究。这项研究的结果可以为缩短类风湿关节炎患者预期寿命的疾病提供急需的信息，并可以确定未来治疗的新靶点。

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.