Molecular Analysis Of Neutrophil Activation By Chemoattr

该项目的目的是确定血液白细胞迁移到炎症或感染的特定组织部位的分子机制。我们关注的是介导这一过程的化学引诱蛋白，并已经确定了部署在白细胞细胞表面的化学引诱受体大家族的成员。我们还发现了由病毒（包括疱疹病毒、痘病毒和艾滋病毒）制造的多种化学引诱剂和化学引诱剂受体模拟物的成员。我们使用基因组学、分子生物学、细胞生物学和流行病学，并与病毒学家合作，作为分析这些分子的主要方法。在前几年解决并在2003财年继续解决的一个主要问题是确定个别化学引诱剂和化学引诱剂受体的特定疾病关联，以便确定潜在的新治疗靶点。在这方面，我们发现趋化因子受体CX3CR1的失活变体CX3CR1- m280与动脉粥样硬化风险降低高度相关。这一结果是通过弗雷明汉心脏研究获得的，该研究是描述心血管疾病危险因素的金标准患者队列。此外，该结果在实验室创建的CX3CR1敲除小鼠中得到证实，发现其动脉粥样硬化风险显着降低。这表明CX3CR1可能是动脉粥样硬化药物开发的合适靶点。因为即使在杂合子中，CX3CR1敲除等位基因和CX3CR1- m280都与动脉粥样硬化风险降低相关，我们假设CX3CR1受体的表达可能是有限的，其调节可能对理解动脉粥样硬化和其他炎症性疾病过程很重要。在这方面，我们研究了IL-15对NK细胞中CX3CR1表达的影响，因为NK细胞表达高水平的受体并依赖于IL-15的功能。出乎意料的是，我们发现IL-15在体外和体内小鼠模型中都是NK细胞上CX3CR1表达的有效负调节因子。同样出乎意料的是，IL-2具有相反的作用。这些结果表明，γ -c细胞因子IL-2和IL-15通过相同的受体链发出信号，必须使用不同的信号通路来影响CX3CR1的表达，并且在细胞治疗应用中，IL-15的NK细胞扩增可能会削弱CX3CR1介导的运输细胞。

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.