Chaperones, ROS systems, & IGF-1:Roles in vascular aging

描述(由申请人提供)：这项建议的主要目的是研究在小鼠衰老过程中调节血管壁表型变化的分子机制。研究人员将使用几个实验动物模型来研究三种生理调节系统的作用，这三种系统都已被证明可以改变对压力的反应。这些包括胰岛素样生长因子I(IGF-I)信号的减少，在低等生物体中，IGF-I信号已被证明可以增强热休克蛋白对应激的反应和在氧化应激中生存的能力，以及修改多种组织中与年龄相关的变化。这些研究将确定这一发现是否在低等生物体中延伸到小鼠身上，以及如果特定的受体亚型(例如生长激素或IGF-I)介导了这种反应，将检查的第二个系统是调节活性氧物种的生成。超氧化物歧化酶1和2(SOD-1和2)在改变血管衰老中的作用将通过改变它们的表达和P47Phox来研究，进而确定其对衰老血管表型的影响。这些成分的变化与IGF-I和CHIP功能变化之间的相互作用以及它们如何改变血管老化反应将被定义，基因图谱将被用于识别当ROS增加时发生的其他分子变化。第三个系列的研究将调查分子伴侣在控制血管系统中与年龄相关的变化中的作用。CHIP是热休克蛋白对应激反应的修饰物，在改变对ROS操作的反应和损伤形成中的作用将被研究。这些基因的修饰在改变动脉粥样硬化对血管损伤的反应中的作用将被检验。股动脉将被剥离，并对14-28天后形成的动脉粥样硬化病变进行分析，以确定这些成分在病变进展中的作用。几种类型的基因改变的小鼠将与APOE缺陷的小鼠杂交，并将分析自发高胆固醇血症诱导的动脉粥样硬化病变的发展。这些结果应该明确这些信号系统的改变与衰老血管表型和新生内膜形成的发展之间的关系。由于IGF-I信号、ROS系统的产生和ChIP的表达在控制IROS的产生和IGF-I信号的表达之间存在交互作用，因此分析这三个系统之间的相互作用可能有助于进一步深入了解调控正常血管壁这些变化的分子机制及其在支持新生内膜形成中的作用。

DESCRIPTION (provided by applicant): The major purpose of this proposal is to investigate the molecular mechanisms that regulate phenotypic changes that occur in blood vessel walls during aging in mice. The investigators will use several experimental animal models to investigate the roles of three physiologic regulatory systems that have each been shown to modify the response to stress. These include reduction in insulin like growth factor I (IGF-I) signaling, which in lower organisms has been shown to enhance the heatshock protein response to stress and the ability to survive oxidative stress as well as modifications of age related changes in multiple tissues. These studies will determine if this finding in lower organisms extends to mice and if a particular receptor subtype (e.g. growth hormone or IGF-I) mediates this response, A second system that will be examined is regulation of generation of reactive oxygen species. The roles of superoxide dismutase 1 and 2 (SOD-1 & 2) in altering vascular aging will be investigated by altering their expression as well as p47 phox and then determine the outcome on the aging vascular phenotype. The interactions between changes in these components and changes in IGF-I and CHIP function and how they modify the vascular aging response will be defined, Gene profiling will be used to identify other molecular changes that occur when ROS are increased. A third series of studies will investigate the role of molecular chaperones in controlling age-related changes in the vasculature. The role of CHIP, a modifier of the heat shock protein response to stress, in altering the response to ROS manipulation and in lesion formation will be investigated. The role of modifying these genes in altering the atherosclerotic response that occurs in response to vascular injury will be examined. Femoral arteries will be denuded and the atherosclerotic lesions that form after 14-28 days analyzed to determine the role of each of these components in lesion progression. Several types of genetically altered mice will be crossed with APOE deficient mice and the development of spontaneous hypercholesterolemic induced atherosclerotic lesions will be analyzed. The results should define the relationship between alteration of each of these signaling systems and both the development of the aging vascular phenotype and in neointimal formation. Since there are interactions between IGF-I signaling, ROS system generation and expression of CHIP in controlling both IROS production and IGF-I signaling, analysis of the interactions among each of these three systems may provide further insight into molecular mechanisms that regulate these changes in normal vessel walls and their roles in supporting neointimal formation.