Molecular Analysis Of Neutrophil Activation By Chemoattr

该项目的目的是确定血液白细胞迁移到发炎或感染的特定组织部位的分子机制。我们已经集中在介导这一过程的趋化蛋白，并确定了一个大家族的趋化受体，部署在白细胞表面的成员。我们还鉴定了由病毒（包括疱疹病毒、痘病毒和HIV）产生的不同化学引诱物和化学引诱物受体模拟物。我们使用基因组学，分子生物学，细胞生物学和流行病学，以及与病毒学家的合作，作为分析这些分子的主要方法。前几年提出并在2003财政年度继续提出的一个主要问题是确定单个趋化因子和趋化因子受体的特定疾病相关性，以确定潜在的新治疗靶点。在这方面，我们发现趋化因子受体CX 3CR 1的失活变体CX 3CR 1-M280与动脉粥样硬化风险降低高度相关。这一结果是通过对心脏病研究的研究获得的，心脏病研究是描述心血管疾病风险因素的金标准患者队列。此外，该结果在实验室创建的CX 3CR 1敲除小鼠中得到证实，发现其动脉粥样硬化的风险显着降低。这表明CX 3CR 1可能是动脉粥样硬化药物开发的合适靶点。由于CX 3CR 1基因敲除等位基因和CX 3CR 1-M280都与动脉粥样硬化风险降低相关，即使在杂合子中，我们假设CX 3CR 1受体表达可能是限制性的，并且其调节对于理解动脉粥样硬化和其他炎症性疾病过程可能是重要的。在这方面，我们已经检查了IL-15对NK细胞中CX 3CR 1表达的影响，因为这些细胞表达高水平的受体并且依赖于IL-15功能。出乎意料的是，我们发现IL-15是体外和体内小鼠模型中NK细胞上CX 3CR 1表达的有效负调节剂。同样出乎意料的是，IL-2具有相反的效果。这些结果表明，γ-c细胞因子IL-2和IL-15通过相同的受体链进行信号传导，必须使用不同的信号传导途径来影响CX 3CR 1表达，并且NK细胞的IL-15扩增可能会削弱细胞在细胞治疗应用中的CX 3CR 1介导的运输。

The aim of this project is to define the molecular mechanisms by which blood leukocytes migrate to specific tissue sites that are inflamed or infected. We have focused on chemoattractant proteins that mediate this process and have identified members of a large family of chemoattractant receptors that are deployed on the leukocyte cell surface. We have also identified members of a diverse group of chemoattractant and chemoattractant receptor mimics made by viruses, including herpesviruses, poxviruses and HIV. We use genomics, molecular biology, cell biology and epidemiology, and collaborations with virologists, as the principle methods for analyzing these molecules. A major question addressed in previous years and continued in FY2003 is to identify specific disease associations of individual chemoattractant and chemoattractant receptors, in order to identify potential new therapeutic targets. In this regard, we have found that CX3CR1-M280, an inactive variant of the chemokine receptor CX3CR1, is highly associated with decreased risk of atherosclerosis. This result was obtained through study of the Framingham Heart Study, the gold standard patient cohort for delineating risk factors for cardiovascular disease. Moreover, the result was confirmed in a CX3CR1 knockout mouse created in the lab, which was found to have a markedly reduced risk of atherosclerosis. This suggests that CX3CR1 may be a suitable target for drug development in atherosclerosis. Because the CX3CR1 knockout allele and CX3CR1-M280 are both associated with reduced risk of atherosclerosis even in heterozygotes, we have hypothesized that CX3CR1 receptor expression may be limiting and that its regulation may be important for understanding atherosclerosis and other inflammatory disease processes. In this regard we have examined the effect of IL-15 on CX3CR1 expression in NK cells, since these cells express high levels of the receptor and are dependent on IL-15 function. Unexpectedly we found that IL-15 is a potent negative regulator of CX3CR1 expression on NK cells in a mouse model, both in vitro and in vivo. Also unexpectedly, IL-2 has the opposite effect. These results suggest that the gamma-c cytokines IL-2 and IL-15, which signal through the same receptor chains, must use differential signaling pathways to affect CX3CR1 expression and that IL-15 expansion of NK cells may cripple the cells with regard to CX3CR1-mediated trafficking in cell therapy applications.