Control of NF-kappaB and Inflammation by COMMD proteins

COMMD 蛋白对 NF-kappaB 和炎症的控制

• 批准号: 8431993
• 负责人: Ezra Burstein
• 金额: $ 33.37万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-02-01 至 2016-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8431993
• 关键词: Animal Model; Anti-Inflammatory Agents; Anti-inflammatory; Area; Attention; Binding; Biological; Cell physiology; Chromatin; Complex; Constitutional; DNA Binding; Data; Disease; Embryo; Evaluation; Event; Figs - dietary; Future; Gene Expression; Gene Expression Regulation; Gene Targeting; Genes; Goals; Grant; Host Defense; Human; Immune; Immune System Diseases; Immune response; Immune system; Immunity; Infection; Inflammation; Inflammatory; Inflammatory Response; Lead; Learning; Link; Malignant Neoplasms; Mediating; Modeling; Modification; Mus; Mutation; Myelogenous; Myeloid Cells; NF-kappa B; Natural Immunity; Pathogenesis; Pathway interactions; Phosphorylation; Play; Post-Translational Protein Processing; Predisposition; Protein Family; Proteins; Recruitment Activity; Regulation; Reporting; Resistance; Role; Sepsis; Site; Systemic infection; Testing; Tissues; Transcription Repressor/Corepressor; Ubiquitination; adaptive immunity; arm; base; cancer risk; cofactor; genome-wide; human disease; in vivo; inhibitor/antagonist; insight; member; microbial; mouse model; mutant; novel; prevent; promoter; protein B; protein degradation; response; transcription factor; ubiquitin ligase

DESCRIPTION (provided by applicant): NF-?B is a conserved transcription factor that plays an essential role in the host defense to infection. While considerable advances have been made in our understanding of how NF-?B is activated, lesser is known about how its activity is terminated. Nevertheless, in terms of disease mechanism, it is likely that alterations in the mechanisms responsible for terminating NF-?B play a central role in persistent inflammation. Studies supported by this grant identified that the degradation of DNA-bound NF-?B subunits is a critical mechanism for transcriptional termination. We identified a ubiquitin ligase responsible for these effects, which contains as an essential cofactor the protein known as COMMD1. This pathway primarily limits the expression of pro-inflammatory genes and post-translational modifications (PTMs) of the NF-?B subunit RelA are required for protein degradation. Key outstanding questions include whether COMMD1 can control inflammation in vivo, how is this pathway specifically regulating pro-inflammatory genes, and what are the precise PTMs that trigger RelA ubiquitination. Our goal is to investigate the role of COMMD1 in inflammation in vivo and to uncover key mechanisms that control its activity in the innate immune system. Based on preliminary data we hypothesize that COMMD1 is an anti-inflammatory factor that cooperates with inducible PTMs such as sumoylation and phosphorylation in order to regulate pro-inflammatory genes. In pursuit of our goal, we propose these Specific Aims: (1) Role of Commd1 in inflammatory responses in vivo: We find that COMMD1 expression is repressed in the setting of inflammatory diseases, suggesting that this phenomenon may contribute to persistent and/or more severe inflammation. To test this notion, we have generated myeloid specific Commd1-/- mice, which display increased susceptibility to LPS administration. Here we will utilize this unique mouse model to evaluate the role of termination mechanisms in the control of inflammation during sepsis. (2) Basis for gene-specific chromatin recruitment of COMMD1: Gene-specific recruitment of COMMD1 occurs through a yet unknown mechanism. Preliminary studies suggest that SUMO binding by COMMD1 is responsible for chromatin binding. Here we will examine the link between SUMO binding and chromatin recruitment to pro-inflammatory gene promoters. The relevance of these events in immune regulation will be assessed by introducing SUMO binding defective mutants into Commd1-/- myeloid cells. (2) Control of termination by PTMs of NF-?B /RelA: In addition to COMMD1 recruitment to chromatin, PTMs of RelA are required for protein degradation. In this Aim we will define the PTMs required to target RelA for degradation and will assess the biological significance of these PTMs by reintroducing degradation-resistant forms of RelA into rela-/- myeloid cells. Altogether, this proposal will tackle a critically significant problem that will propel the NF-?B field forward by providing important insights into homeostatic mechanisms that prevent persistent inflammation.

描述（由申请人提供）：NF-？B是一种保守的转录因子，在宿主防御感染中起重要作用。虽然我们对NF-？B是被激活的，但其活性是如何终止的却鲜为人知。然而，就疾病机制而言，负责终止NF-？B在持续炎症中起核心作用。该基金支持的研究发现，dna结合的NF-？B亚基是转录终止的关键机制。我们发现了一种泛素连接酶负责这些作用，它含有一种称为COMMD1的必要辅助因子。这一途径主要限制了促炎基因的表达和NF-？B亚基RelA是蛋白质降解所必需的。关键的悬而未决的问题包括COMMD1是否可以控制体内炎症，该途径如何特异性调节促炎基因，以及触发RelA泛素化的精确PTMs是什么。我们的目标是研究COMMD1在体内炎症中的作用，并揭示在先天免疫系统中控制其活性的关键机制。根据初步数据，我们假设COMMD1是一种抗炎因子，它与可诱导的ptm（如sumoylation和磷酸化）协同调节促炎基因。为了实现我们的目标，我们提出了以下具体目标：(1)Commd1在体内炎症反应中的作用：我们发现Commd1的表达在炎症性疾病的环境中被抑制，这表明这种现象可能导致持续和/或更严重的炎症。为了验证这一观点，我们产生了骨髓特异性Commd1-/-小鼠，它们对LPS的敏感性增加。在这里，我们将利用这种独特的小鼠模型来评估终止机制在脓毒症期间炎症控制中的作用。(2) COMMD1基因特异性染色质募集的基础：COMMD1基因特异性募集的发生机制尚不清楚。初步研究表明COMMD1与SUMO的结合是染色质结合的原因。在这里，我们将研究SUMO结合和染色质募集到促炎基因启动子之间的联系。这些事件在免疫调节中的相关性将通过将SUMO结合缺陷突变体引入Commd1-/-骨髓细胞来评估。(2) ptm对NF-?终止的控制B /RelA：除了向染色质募集COMMD1外，RelA的PTMs也是蛋白质降解所必需的。在本研究中，我们将定义针对RelA降解所需的PTMs，并通过将抗降解形式的RelA重新引入RelA -/-髓细胞来评估这些PTMs的生物学意义。总之，这一提议将解决一个至关重要的问题，推动NF-？通过对体内平衡机制预防持续炎症提供重要见解，使B领域向前发展。