Translational control of inflammatory gene expression

项目2的长期目标是阐明调节基因表达的转录后机制。 在脉管系统炎症中的表达。干扰素（IFN）-v是单核细胞/巨噬细胞的经典激活剂， 它诱导炎症生长因子、蛋白酶、趋化因子和基因的快速转录， 自由基物种的产生者。如果不受调控，这一过程将成为慢性和单核细胞/巨噬细胞产物， 积累、损伤宿主组织，并导致慢性血管疾病，例如，动脉粥样硬化 炎症的终止不是在消除初始损伤后开始的被动过程; 相反，内在机制积极限制潜在有害蛋白质的表达。近日，在... OR已经认识到转录后过程在限制或解决炎症中的重要作用。 我们已经发现了一种新的翻译控制途径，作为内源性调节剂， 炎症反应。在骨髓细胞中，IFN-γ诱导异源四聚体IFN-γ-IFN-γ的组装。 激活的翻译抑制剂（GAIT）复合物，结合3 '非翻译区的RNA元件 某些促炎性靶mRNA，例如，血管内皮生长因子-A，并抑制其 翻译.在初步研究中，我们发现一种GAIT蛋白，谷氨酰-脯氨酰-tRNA合成酶（EPRS）， 是GAIT系统的核心，因为它负责靶mRNA的识别，其功能是调节的。 通过磷酸化和其他3种GAIT蛋白的结合来活化。我们认为EPRS不是一种惰性的蛋白质- 结合支架，而是一个动态系统，受到刺激诱导的修饰，调节GAIT 复杂的装配和功能。基于这些结果，我们提出了以下假设：磷酰基- IFN-y依赖性激酶对EPRS的作用引起EPRS的构象变化，从而调节装配 GAIT复合物，沉默炎症mRNA靶点的翻译，并有助于解决 慢性炎症。我们将通过追求三个具体目标来检验这一假设。在目标1中， 确定GAIT复合物组装和GAIT元件结合所需的EPRS结构域。在目标2中， 将决定EPRS磷酸化在GAIT复合物组装和功能中的作用。在目标3中， 研究EPRS和GAIT复合物的体内抗炎作用。 相关性（参见说明）： 我们的研究将阐明一个新的途径，调节炎症蛋白的合成巨噬细胞， 在血管疾病如动脉粥样硬化的发展中的重要过程。正在调查的途径 有助于限制和解决慢性炎症，慢性炎症是疾病进展的重要致病因素。 更深入地了解炎症“停止”途径是很重要的，因为这些途径的缺陷可以导致 血管疾病，因为途径本身可能为开发新的抗- 炎症治疗学。

The long-term goal of Project 2 is to elucidate the post-transcriptional mechanisms that modulate gene expression in inflammation of the vasculature. Interferon (IFN)-v is the classic activator of monocyte/macro- phages, and it induces rapid transcription of inflammatory growth factors, proteases, chemokines, and gen- erators of radical species. If unregulated, this process becomes chronic and monocyte/macrophage products accumulate, damage host tissue, and contribute to chronic disorders of blood vessels, e.g., atherosclerosis. The termination of inflammation is not a passive process that begins after elimination of the initial insult; in contrast, intrinsic mechanisms actively limit expression of potentially injurious proteins. Recently, investigat- ors have recognized the important role of post-transcriptional processes in limiting or resolving inflammation. We have discovered a novel translational control pathway that acts as an endogenous regulator of the inflammatory response. In myeloid cells, IFN-y induces assembly of the heterotetrameric, IFN-Gamma- Activated inhibitor of Translation (GAIT) complex, which binds an RNA element in the 3'untranslated region of certain pro-inflammatory target mRNAs, e.g., vascular endothelial growth factor-A, and inhibits their translation. In Preliminary Studies we show that one GAIT protein, glutamyl-prolyl-tRNA synthetase (EPRS), is central to the GAIT system because it is responsible for target mRNA recognition, and its function is regu- lated by phosphorylation and binding of the other 3 GAIT proteins. We suggest EPRS is not an inert, protein- binding scaffold, but rather a dynamic system subject to stimulus-inducible modifications that regulate GAIT complex assembly and function. Based on these results, we propose the following hypothesis: Phosphoryl- ation of EPRS by IFN-y-dependent kinases causes conformational changes in EPRS that regulate assembly of the GAIT complex, which silences translation of inflammatory mRNA targets and contributes to the resolu- tion of chronic inflammation. We will test this hypothesis by pursuit of three Specific Aims. In Aim 1 we will determine the EPRS domains required for GAIT complex assembly and GAIT element-binding. In Aim 2 we will determine the role of EPRS phosphorylation in GAIT complex assembly and function. In Aim 3 we will investigate the anti-inflammatory function of EPRS and the GAIT complex in vivo. RELEVANCE (See instructions): Our studies will elucidate a new pathway that regulates the synthesis of inflammatory proteins by macrophages, an important process in the development of vascular diseases such as atherosclerosis. The pathway under investigation contributes to the limitation and resolution of chronic inflammation, an important causative factor in disease progression. A deeper understanding of inflammatory "stop" pathways is important because defects in these pathways can contribute to vascular disorders, and because the pathway itself may present alternative targets for development of novel anti- inflammatory therapeutics.