Mechanisms of Macrophage Activation

巨噬细胞激活机制

• 批准号: 6789253
• 负责人: THOMAS A. HAMILTON
• 金额: $ 28.76万
• 依托单位: CLEVELAND CLINIC LERNER COM-CWRU
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-08-15 至 2008-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6789253
• 关键词: RNA binding protein; cell free system; chemical stability; immunogenetics; inflammation; interferon gamma; interleukin 10; laboratory mouse; leukocyte activation /transformation; lipopolysaccharides; macrophage; messenger RNA; nucleic acid sequence; posttranscriptional RNA processing; protein localization; transforming growth factors

DESCRIPTION (provided by applicant): The contribution of mononuclear phagocytes in host response to cancer is determined in large part through the pattern of gene expression induced in response to stimuli encountered in the tumor microenvironment. Control of macrophage gene expression in response to prototypic pro-inflammatory (IFNgamma and LPS) or anti-inflammatory agents (IL-10 and TGFbeta) results from the integration of multiple intracellular signals that operate at both transcriptional and post-transcriptional levels. Current knowledge of post-transcriptional regulation of specific mRNA stability is limited. AU rich sequence elements (AREs) in the 3' untranslated regions (UTRs) of many cytokine and chemokine mRNAs in concert with ARE-specific RNA binding proteins lead to rapid mRNA decay. We and others have shown that pro-inflammatory or anti-inflammatory stimuli can stabilize or destabilize, respectively, selected chemokine mRNAs particularly KC (mouse CXCL1). These findings lead to the general hypothesis that post-transcriptional control of transiently expressed inflammatory genes involves the induced stabilization of unstable mRNAs through a process that operates in sequence specific fashion. Anti-inflammatory agents act by antagonizing this response. At present multiple features of this model remain undefined. These include (a) the sequence determinants for stimulus-dependent response, (b) how signaling pathways initiated by stabilizing and/or destabilizing agents are integrated and coupled with control of mRNA stability, (c) which steps in mRNA decay are altered by stabilizing or destabilizing stimuli and (d) how ARE-binding proteins couple signaling events to effector mechanisms responsible for the changes in mRNA decay. We now propose to address these issues as a further test of the hypothesis by performance of the following specific experimental aims. 1. Evaluate the sequence basis for ARE-dependent, stimulus-mediated control of mRNA stability. 2. Evaluate signaling pathways involved in the control of mRNA stability by LPS, IL-10 and TGFbeta. 3. Identify the mRNA decay mechanisms that are subject to stimulus-dependent modulation. 4. Determine the role of known ARE/RNA binding proteins in LPS-induced stabilization and IL-10 or TGFbeta-mediated destabilization

描述（由申请人提供）：单核吞噬细胞在宿主对癌症的反应中的贡献很大程度上是通过响应肿瘤微环境中遇到的刺激而诱导的基因表达模式来确定的。响应原型促炎剂（IFNγ 和 LPS）或抗炎剂（IL-10 和 TGFbeta）而控制巨噬细胞基因表达是由在转录和转录后水平上起作用的多个细胞内信号的整合产生的。目前对特定 mRNA 稳定性转录后调控的了解有限。许多细胞因子和趋化因子 mRNA 的 3' 非翻译区 (UTR) 中的所有丰富序列元件 (ARE) 与 ARE 特异性 RNA 结合蛋白共同导致 mRNA 快速衰减。我们和其他人已经证明，促炎或抗炎刺激可以分别稳定或破坏选定的趋化因子 mRNA，特别是 KC（小鼠 CXCL1）。这些发现引出了一个普遍的假设，即瞬时表达炎症基因的转录后控制涉及通过以序列特异性方式运行的过程诱导不稳定 mRNA 的稳定。抗炎剂通过拮抗这种反应来发挥作用。目前该模型的多个功能仍未定义。这些包括（a）刺激依赖性反应的序列决定因素，（b）稳定剂和/或去稳定剂引发的信号传导途径如何整合并与mRNA稳定性的控制相结合，（c）稳定或去稳定刺激改变mRNA衰变的哪些步骤，以及（d）ARE结合蛋白如何将信号传导事件与负责mRNA衰变变化的效应器机制耦合。我们现在建议通过执行以下具体实验目标来解决这些问题，作为对假设的进一步检验。 1. 评估 ARE 依赖性、刺激介导的 mRNA 稳定性控制的序列基础。 2. 评估 LPS、IL-10 和 TGFbeta 控制 mRNA 稳定性所涉及的信号通路。 3. 确定受刺激依赖性调节的 mRNA 衰减机制。 4. 确定已知 ARE/RNA 结合蛋白在 LPS 诱导的稳定和 IL-10 或 TGFbeta 介导的不稳定中的作用