Novel pathways controlling macrophage inflammation and resolution in atherosclerosis

总结 尽管有降低胆固醇的有效策略，动脉粥样硬化和相关的心血管疾病 仍然是全球健康的主要负担。近年来的工作突出了令人兴奋的治疗潜力， 减少炎症的干预措施，以及需要确定新的和选择性的目标。我们漫长 长期目标是了解脂质代谢和炎症如何相互作用，以及这些相互作用如何影响 在治疗上有用。目前研究的目的是确定转录的作用 核因子红细胞2相关因子-1（Nrf 1;也称为Nfe 2L 1）在连接这两个过程中的作用。 核心假设是巨噬细胞中的Nrf 1是预防慢性炎症的关键因素， 维持胆固醇稳态，增强Nrf 1的这些作用可能有益于 动脉粥样硬化这是基于令人信服的新的初步数据，显示Nrf 1在巨噬细胞中被激活， 并且对于脂质代谢途径基因的表达是必需的， 对于炎症状态的正确解决至关重要。以前的研究结果也表明，Nrf 1的缺失 严重损害细胞胆固醇稳态。拟议研究的基本原理是， 巨噬细胞Nrf 1功能和作用机制可能为研究巨噬细胞的调控机制提供重要线索 炎症和解决一般，并揭示了一种新的治疗动脉粥样硬化的治疗靶点。 中心假设将通过追求三个具体目标进行测试：1）检查Nrf 1在 2）阐明Nrf 1在巨噬细胞中作用的分子机制; 3）探索Nrf 1在巨噬细胞中的作用机制。 巨噬细胞-Nrf 1在体内动脉粥样硬化中重要性在第一个目标下，组织特异性诱导缺失 在申请人实验室建立和测试的模型将用于对功能进行全面表征 Nrf 1在炎症输出、脂质代谢和炎症消退中的作用。这一目标还将探讨 胆固醇对Nrf 1功能的影响，以及Nrf 1在调节胆固醇稳态中的相互作用， 巨噬细胞在第二个目标中，免疫沉淀容易获得的与DNA偶联的标记蛋白质， 测序和MS/MS分析将鉴定Nrf 1的蛋白质相互作用物和翻译后修饰 潜在地调节其功能。第三个目标是测试Nrf 1缺陷和过表达对 使用已经建立的西方饮食喂养的Ldlr缺陷小鼠体内动脉粥样硬化， Nrf 1的特异性缺失，或腺相关病毒（AAV）介导的Nrf 1的巨噬细胞特异性过表达。 该方法具有创新性，因为它试图通过使用 巨噬细胞内自然存在的系统。这项研究意义重大，因为目前 在动脉粥样硬化的情况下激活内源性炎症消退的方法是有限的， 这项研究可能为动脉粥样硬化中分辨率的作用提供重要的见解，并揭示一种新的 治疗靶点

Summary In-spite of effective strategies for lowering cholesterol, atherosclerosis and associated cardiovascular diseases remain a major global health burden. Work in recent years has highlighted the exciting therapeutic potential for interventions that reduce inflammation, as well as the need for identifying novel and selective targets. Our long term goal is to understand how lipid metabolism and inflammation interact, and how these interactions can be useful therapeutically. The objective of the current research proposal is to determine the role of the transcription factor Nuclear factor erythroid 2 related factor-1 (Nrf1; also known as Nfe2L1) in linking these two processes. The central hypothesis is that Nrf1 in the macrophage is a critical factor for preventing chronic inflammation and maintaining cholesterol homeostasis, and that enhancing these actions of Nrf1 may be beneficial in atherosclerosis. This is based on compelling new preliminary data showing that Nrf1 is activated in macrophages in response to inflammatory stimuli and is necessary for the expression of lipid metabolism pathway genes that are crucial for proper resolution of the inflammatory state. Previous results also showed that deletion of Nrf1 drastically impairs cellular cholesterol homeostasis.The rationale for the proposed research is that understanding the function and mechanism of macrophage Nrf1 may provide important insight into regulation of macrophage inflammation and resolution in general and reveal a novel therapeutic target for the treatment of atherosclerosis. The central hypothesis will be tested by pursuing three specific aims: 1) Examine the function of Nrf1 in macrophages; 2) Elucidate the molecular mechanism of Nrf1 action in macrophages; and 3) Explore the importance of macrophage-Nrf1 in atherosclerosis in-vivo. Under the first aim, tissue-specific inducible deletion models established and tested in the applicant's lab will be used for a thorough characterization of the function of Nrf1 in inflammatory output, lipid metabolism and resolution of inflammation. This aim will also explore the impact of cholesterol on Nrf1 function, and the reciprocal role of Nrf1 in regulating cholesterol homeostasis in macrophages. In the second aim, immunoprecipitation of readily available tagged protein coupled to DNA sequencing and MS/MS analysis will identify, protein interactors and post translational modifications of Nrf1 potentially mediating its function. The third aim will test the impact of Nrf1 deficiency and overexpression on atherosclerosis in-vivo using already established Western-diet fed Ldlr-deficient mice with either macrophage specific deletion of Nrf1, or adeno-associated-virus (AAV) mediated macrophage specific overexpression of Nrf1. The approach is innovative because it attempts to overcome issues of pro-resolving mediator delivery by using naturally existing systems within macrophages. The proposed research is significant, because current approaches to activate endogenous resolution of inflammation in the context of atherosclerosis are limited, and this study might provide important insight into the role of the resolution in atherosclerosis and reveal a novel therapeutic target.