Inducible Macrophage Specific Gene Expression in Diseases

描述(申请人提供)：开发转基因动物模型，为了解人类慢性炎症提供信息。巨噬细胞在多种慢性炎症性疾病的发病机制中起关键作用。使用基因敲除小鼠的研究使研究人员能够检查巨噬细胞特异性基因的重要作用。然而，这些研究仅限于在多个组织中表达的基因，因为还没有巨噬细胞特异的基因敲除小鼠。由于基因的丢失可能会阻止单核细胞在其实际到达损伤部位之前的分化或迁移，因此产生可诱导的巨噬细胞特异性敲除是研究慢性炎症性疾病的首选方法。本实验室利用清道夫受体A启动子(SRA-Cre)建立了一种新的针对组织巨噬细胞表达Cre重组酶的转基因小鼠模型。在被他莫昔芬诱导后，Cre将切割巨噬细胞中的任何“漂浮”基因。我们的模型还将允许在疾病的任何阶段敲除基因。我们建议的主要目标是用三个目标来描述这个新的条件鼠模型。在第一个目标中，SRA-Cre小鼠将进入一个报告系，并将在三种肺损伤模型(香烟烟雾暴露、哮喘和急性肺损伤)中评估Cre表达的特异性和诱导性。在第二个目标中，SRA-CRE小鼠将被交叉进入载脂蛋白E(APOE)基因敲除背景。将分析动脉粥样硬化斑块中病变巨噬细胞和泡沫细胞中CRE的表达。这种表达巨噬细胞特异性CRE的APOE基因敲除模型将被用于研究巨噬细胞在动脉粥样硬化中的功能的实验室。在第三个目标中，我们将建立一个有条件的、巨噬细胞特异性的金属蛋白酶组织抑制因子-3(TIMP-3)基因敲除模型。TIMP-3在巨噬细胞中表达，在炎症性疾病中发挥重要作用。然而，全球TIMP-3基因敲除小鼠的肺和心脏显示出发育异常。我们已经生成了一个浮动的TIMP-3模型，它将被交叉到SRA-CRE背景中。利用这个模型，我们将确定巨噬细胞中TIMP-3的缺失如何影响吸烟所致的肺损伤。我们新的有条件的巨噬细胞特异性靶向模型将是一个非常有价值的工具，使研究人员能够准确评估巨噬细胞表达的基因在慢性炎症性疾病中的作用和功能。 公共卫生相关性：巨噬细胞在多种慢性炎症性疾病的发病机制中起关键作用。在这个提案中，我们将描述一种新开发的条件性巨噬细胞特异性小鼠模型，其中Cre重组酶受清道夫受体A启动子的调控。我们的模型将允许仅在巨噬细胞和疾病的任何阶段敲除感兴趣的基因。我们建议的主要目标是建立一个小鼠模型，使研究人员能够在慢性炎症性疾病期间特异性和有条件地敲除巨噬细胞中感兴趣的基因。这个模型将是一个非常有价值的模型，使研究人员能够准确地评估巨噬细胞表达的基因在慢性炎症性疾病中的作用和功能。此外，我们建议将这一模型与易发生动脉粥样硬化的APOE基因敲除模型相结合，以检测这种重要血管疾病中的巨噬细胞基因。我们还将研究巨噬细胞金属蛋白酶组织抑制物-3缺失在肺损伤中的后果。

DESCRIPTION (provided by applicant): Develop transgenic animal models that are informative for understanding chronic inflammation in humans. Macrophages play a key role in the pathogenesis of multiple chronic inflammatory diseases. Studies using knockout mice have allowed investigators to examine the important role of macrophage-specific genes. However, these studies are limited to genes expressed in multiple tissues, as macrophage-specific knockout mice are not available. Since the loss of a gene may prevent the differentiation or migration of the monocyte prior to its actual arrival at the site of injury, the generation of an inducible, macrophage-specific knockout is preferable to study chronic inflammatory diseases. Our laboratory has developed a new transgenic mouse model targeting Cre recombinase expression in tissue macrophage, using the scavenger receptor A promoter (SRA-Cre). After its induction with tamoxifen, Cre will cleave any "floxed" gene in macrophages. Our model will also allow to knockout genes at any stage of the disease. The main goal of our proposal is to characterize this new conditional mouse model, using three aims. In the first aim, SRA-Cre mice will be crossed into a reporter line, and specificity and inducibility of Cre expression will be assessed in three models of lung injury (cigarette smoke exposure, asthma, and acute lung injury). In the second aim, SRA-Cre mice will be crossed into the apolipoprotein-E (Apoe) knockout background. Atherosclerotic plaques will be analyzed for expression of Cre in lesion macrophages and foam cells. This macrophage-specific Cre- expressing Apoe knockout model will be made available to laboratories studying the function of macrophages in atherosclerosis. In a third aim, we will generate of a conditional, macrophage- specific Tissue Inhibitor of Metalloproteinase-3 (Timp-3) knockout model. TIMP-3 is expressed in macrophage and plays an important role in inflammatory diseases. However, global Timp-3 knockout mice exhibited developmental abnormalities in the lung and the heart. We have generated a floxed Timp-3 model, which will be crossed into the SRA-Cre background. Utilizing this model, we will determine how the absence of TIMP-3 in macrophages affects lung injury due to cigarette smoke. Our new conditional, macrophage-specific targeting model will be a highly valuable tool, allowing researchers to precisely assess the roles and functions of genes expressed by macrophages during chronic inflammatory diseases. PUBLIC HEALTH RELEVANCE: Macrophages play a key role in the pathogenesis of multiple chronic inflammatory diseases. In this proposal, we will characterize a newly developed conditional, macrophage-specific mouse model, where Cre recombinase is regulated by the scavenger receptor A promoter. Our model will allow to knockout genes of interest only in macrophages and at any stage of the disease. The major goal of our proposal is to generate a mouse model that will allow researchers to specifically and conditionally knockout genes of interest in macrophages during chronic inflammatory diseases. This model will be a highly valuable model, allowing researchers to precisely assess the roles and functions of genes expressed by macrophages during chronic inflammatory diseases. In addition, we propose to cross this model into the atherosclerosis-prone Apoe knockout model, to allow examination of macrophage genes in this important vascular disease. We will also examine the consequences of the absence of macrophage tissue inhibitor of metalloproteinases-3 in lung injury.