Roles of RelB in tuning inflammatory and innate immune responses

项目摘要/摘要 在这个项目中，我们将寻求更好的理解为什么以及如何缺乏NFκB RelB的小鼠品系 蛋白质被认为是非规范的NFκB途径的主要效应者，它会发展成严重的炎症和 自身免疫性疾病。尽管之前的研究主要集中在核因子κB反应基因上，但我们没有偏见 转录测量(初步结果)显示，缺乏RelB的巨噬细胞和树突状细胞 由于干扰素刺激基因(ISGs)的高表达，细胞显示出戏剧性的高表达 干扰素-β。I型干扰素调节系统在抗原提呈细胞中的高活性确实可以解释 RelB基因敲除小鼠T细胞介导的自身免疫表型。拟议的项目解决了 压倒一切的假设是，RelB作为一个关键的信号节点发挥作用，微调炎症和 天然免疫向获得性免疫转变过程中干扰素介导的反应。 在第一个特定目标中，我们将首先表征RelB对干扰素基因表达的调控。 巨噬细胞和树突状细胞，不仅在RelB基因敲除中，而且在自然产生的脾DC中也显示出 RelB的低表达或高表达(使用新的RelB-Venus报告程序)。我们将研究是否减少 干扰素系统的高活性在基因上会抑制RelB-/-小鼠的自身免疫表型。 在第二个具体目标中，我们将描述RelB如何调节I型干扰素的机制 回应。使用一种新的RelB-DNA结合突变体(RelBdb/db)，我们将区分染色质结合 与细胞质机制的对比。初步结果表明：(1)IRF3的过度激活可能是通过 RelA通过直接结合或稳定RelA捕获的IκBome的方式抑制RelA的细胞质。 (2)RelB：P50可能通过与IRF3竞争结合G-IRE而直接抑制干扰素β的表达 (程等人，2011)。这些机制将在拟议的研究中加以描述。

PROJECT SUMMARY/ABSTRACT In this project we will seek a better understanding of why and how mouse strains lacking the NFκB RelB protein, known as the primary effector of the non-canonical NFκB pathway, develop severe inflammatory and auto-immune disease. Whereas previous studies focused on NFκB response genes, our unbiased transcriptomic measurements (preliminary results) revealed that RelB-deficient macrophages and dendritic cells show dramatic hyper-expression of interferon stimulatory genes (ISGs) due to hyper-expression of interferon-β. Hyper-activity of the type I IFN regulatory system in antigen-presenting cells may indeed explain the T-cell mediated auto-immune phenotype in RelB knockout mice. The proposed project addresses the overarching hypothesis that RelB functions as a critical signaling node that fine-tunes inflammatory and interferon-mediated responses during the transition from innate to adaptive immunity. In the first Specific Aim, we will first characterize the control of interferon gene expression by RelB in macrophages and dendritic cells, not only in RelB knockouts but also naturally occurring splenic DCs that show either low or high expression of RelB (using a novel RelB-Venus reporter). We will examine whether reducing the hyper-activity of the interferon system genetically will suppress the auto-immune phenotype of RelB-/- mice. In the second Specific Aim, we will characterize the mechanism of how RelB regulates type I interferon responses. Using a novel RelB-DNA binding mutant (RelBdb/db), we will distinguish between chromatin-bound vs. cytoplasmic mechanisms. Preliminary results suggest that (i) hyper-activation of IRF3 may be mediated by cytoplasmic inhibition by RelB of RelA, either by direct binding or via stabilizing the RelA-trapping IκBsome, and that (ii) RelB:p50 may directly inhibit IFNβ expression by competing with IRF3 for binding to the G-IRE (Cheng et al 2011). These mechanisms will be delineated in the proposed studies.