Selective Regulation of Pro-inflammatory Genes in Macrophages

描述（由申请人提供）：炎症可能有利于对微生物病原体的正常免疫应答。然而，长期的炎症可以在感染期间促进组织损伤，并且与多种疾病密切相关，包括癌症，动脉粥样硬化和几种炎性自身免疫性疾病。尽管有许多抗炎药物可用，但由于各种原因，包括靶点特异性不足和效力有限，它们中没有一种被认为是理想的。因此，需要新的策略来开发促炎基因和蛋白质的抑制剂。在寻求抑制特定促炎基因转录的药物方面的一个主要限制是，我们对负责选择性基因调控的分子机制的理解仍然是基本的。转录因子如NF-？B和AP-1有助于许多促炎基因的激活。然而，由于其广泛的功能，这些因子可能不是抑制诱导基因的特定子集的合适靶标。在过去的几年中，许多信号转导通路激活的Toll样受体（TLR）和其他跨膜受体已被阐明，导致在识别的途径，导致选择性基因调控的巨大进步。然而，如果不了解与这些基因相关的控制区和DNA序列元件的逻辑组织，就很难完全理解负责促炎基因差异调节的机制。我们的实验室已经发现，在小鼠巨噬细胞中由脂多糖（LPS）诱导的基因可以根据几个标准分为六大类，包括它们（1）对新蛋白质合成的需要，（2）通过ATP依赖性核小体重塑复合物的SWI/SNF家族对核小体重塑的需要，（3）对转录因子IRF 3的需要，和（4）存在CpG岛启动子。本申请中提出的实验集中于四类主要应答基因，其被定义为在没有新蛋白质合成的情况下由LPS信号传导途径直接激活的基因。拟议的实验将检查各种假设，包括假设的关键属性的主要反应基因是刺激特异性的和假设的CpG岛经常与SWI/SNF独立的主要反应基因，因为高CpG含量是不相容的组装稳定的核小体。我们还将研究IRF 3在激活一类特定的SWI/SNF依赖性初级应答基因中的作用。最后，我们将利用含有每个基因类代表性成员的细菌人工染色体，对不同的激活机制进行更详细的分析。总之，这些研究应该大大扩展我们对先天免疫系统细胞中促炎基因选择性调节的认识。 公共卫生相关性：特异性促炎基因的异常表达在许多常见疾病中起主要作用，包括癌症、动脉粥样硬化和许多炎性自身免疫性疾病。值得注意的是，最近的研究表明，一些炎症基因的表达增强有助于预防疾病，而其他基因则会促进疾病的进展。这项研究的目的是更好地了解调节免疫系统细胞中炎症基因差异表达的分子机制。这项研究的长期目标是开发选择性调节促炎基因的药理学策略，从而增强保护性基因的表达并减少有害基因的表达。

DESCRIPTION (provided by applicant): Inflammation can be beneficial for a normal immune response to microbial pathogens. However, prolonged inflammation can promote tissue damage during infection and has been closely linked to a diverse range of diseases, including cancer, atherosclerosis, and several inflammatory autoimmune diseases. Although a number of anti-inflammatory drugs are available, none of them are considered to be ideal for a variety of reasons, including insufficient target specificity and limited potency. Therefore, new strategies are needed for the development of inhibitors of pro-inflammatory genes and proteins. One major limitation in pursuing pharmaceuticals that inhibit the transcription of specific pro-inflammatory genes is that our understanding of the molecular mechanisms responsible for selective gene regulation remains rudimentary. Transcription factors such as NF-?B and AP-1 contribute to the activation of many pro-inflammatory genes. However, because of their broad functions, these factors may not be appropriate targets for the inhibition of specific subsets of inducible genes. During the past few years, a number of signal transduction pathways activated by Toll-like receptors (TLRs) and other transmembrane receptors have been elucidated, resulting in great strides toward the identification of pathways that lead to selective gene regulation. However, it will be difficult to fully appreciate the mechanisms responsible for the differential regulation of pro-inflammatory genes without an understanding of the logical organization of the control regions and DNA sequence elements associated with these genes. Our laboratory has found that genes induced by lipopolysaccharide (LPS) in murine macrophages can be divided into six broad classes on the basis of several criteria, including their (1) requirement for new protein synthesis, (2) requirement for nucleosome remodeling by the SWI/SNF family of ATP-dependent nucleosome remodeling complexes, (3) requirement for the transcription factor IRF3, and (4) the presence of a CpG island promoter. The experiments proposed in this application focus on the four classes of primary response genes, which are defined as genes directly activated by LPS signaling pathways in the absence of new protein synthesis. The proposed experiments will examine a variety of hypotheses, including the hypothesis that the critical properties of primary response genes are stimulus-specific and the hypothesis that CpG islands are frequently associated with SWI/SNF-independent primary response genes because the high CpG-content is incompatible with the assembly of stable nucleosomes. We will also examine the role of IRF3 in the activation of a specific class of SWI/SNF-dependent primary response genes. Finally, we will make use of bacterial artificial chromosomes containing representative members of each gene class to initiate more detailed analyses of the diverse activation mechanisms. Together, these studies should greatly expand our knowledge of the selective regulation of pro-inflammatory genes in cells of the innate immune system. PUBLIC HEALTH RELEVANCE: The aberrant expression of specific pro-inflammatory genes plays a major role in a number of common diseases, including cancer, atherosclerosis, and a number of inflammatory autoimmune disorders. Significantly, recent studies have shown that enhanced expression of some inflammatory genes helps protect against disease, whereas other genes enhance disease progression. The objective of the proposed research is to better understand the molecular mechanisms regulating the differential expression of inflammatory genes in cells of the immune system. The long-term goal of this research is to develop pharmacologic strategies for the selective modulation of pro-inflammatory genes, leading to the enhanced expression of protective genes and reduced expression of detrimental genes.