Regulation of Chemokine Expression In Vivo

描述（由申请方提供）：组织损伤后的炎症是保护生物体免受环境病原体挑战并协调组织结构和稳态恢复的重要过程。这种活性的一个主要方面是依赖于炎性中性粒细胞和单核细胞的顺序浸润，其部分地通过化学引诱细胞因子或趋化因子的产生来调节。在培养的细胞系中进行的研究已经证明，许多细胞类型能够产生趋化因子以响应广谱的试剂。我们的实验室和其他实验室已经证明，趋化因子的表达是通过细胞类型和刺激特异性的转录和mRNA稳定性的改变，这取决于特定的核苷酸调控序列的DNA和mRNA存在于单个趋化因子基因的调节。我们实验室的最新研究结果表明，体内趋化因子的表达以复杂的多相模式发生，可能涉及不同细胞类型和刺激的参与。然而，我们不能准确地预测哪些个体刺激、细胞类型和机制负责在任何给定的炎症环境中观察到的趋化因子基因表达模式。因此，本提案的总体目标是确定从我们的细胞培养模型中鉴定的调控机制如何转化为体内观察到的细胞类型和刺激特异性趋化因子基因表达的复杂模式。这将通过两个实验目标来实现。1.我们将使用皮肤中的手术损伤或接触性超敏反应的小鼠模型来确定（a）每个反应阶段中的主要反应细胞群和（B）负责调节KC和MIP-2趋化因子基因表达的促炎和/或抗炎介质。2.我们将使用转基因小鼠表达的报告转基因含有野生型或突变体版本的规定的监管序列，以确定其在控制细胞类型和刺激特异性趋化因子基因转录和mRNA的稳定性在体内的重要性。

DESCRIPTION (provided by the applicant): Inflammation following tissue injury is an essential process that protects the organism against challenge by environmental pathogens and orchestrates the restoration of tissue architecture and homeostasis. A major aspect of this activity is dependent upon the sequential infiltration of inflammatory neutrophils and monocytes that is regulated, in part, by the production of chemoattractant cytokines or chemokines. Studies conducted in cultured cell lines have demonstrated that many cell types are capable of producing chemokines in response to a broad spectrum of agents. Our laboratory and others have demonstrated that chemokine expression is regulated through cell type- and stimulus-specific alterations in transcription and mRNA stability that depend upon specific nucleotide regulatory sequences in DNA and mRNA present in individual chemokine genes. Recent findings from our laboratory show that chemokine expression in vivo occurs in a complex multiphase pattern that is likely to involve the participation of distinct cell types and stimuli in a temporally ordered fashion. We cannot, however, accurately predict which individual stimuli, cell types, and mechanisms are responsible for the pattern of chemokine gene expression seen in any given inflammatory setting. The overall goal of this proposal, therefore, is to determine how the regulatory mechanisms identified from our cell culture models translate into the complex pattern of cell type- and stimulus-specific chemokine gene expression observed in vivo. This will be accomplished with two experimental objectives. 1. We will use mouse models of surgical injury or contact hypersensitivity in the skin to determine (a) the primary responding cell populations in each phase of response and (b) the pro-inflammatory and/or anti-inflammatory mediators responsible for regulating expression of KC and MIP-2 chemokine genes. 2. We will use transgenic mice expressing reporter transgenes containing wild type or mutant versions of defined regulatory sequences to determine their importance in controlling cell type- and stimulus-specific chemokine gene transcription and mRNA stability in vivo.