Oxidative Stress, p66shc and the Aging Process

描述(由申请人提供)：之前已经产生了p66shc基因缺陷的小鼠，并在一种特定的菌株背景下显示出延长了寿命(Migliaccio等人，1999年)。由于p66shc缺乏是少数几种已报道的延长哺乳动物寿命的遗传干预措施之一，因此研究这一途径如何影响寿命有可能增加我们对衰老机制的理解。我们已经使用基因打靶技术产生了缺乏p66shc的小鼠。这个动物模型是通过选择性地删除胚胎干细胞中p66shc基因的外显子2区域而产生的。我们建议使用新产生的p66shc小鼠来详细研究p66shc在衰老过程中的作用。需要检验的中心假设是，p66shc缺乏将延缓衰老过程，这是由于在靶组织衰老过程中，ROS水平降低，线粒体功能维持，ROS诱导的细胞凋亡减少。以骨骼肌为模型，我们将测试p66shc缺乏是否会防止与年龄相关的线粒体功能障碍、细胞凋亡和与年龄相关的转录改变。此外，我们建议在长寿小鼠的遗传背景下确定p66shc突变对寿命和疾病模式的影响。先前的一项研究已经为p66shc缺陷和延缓衰老过程之间的联系提供了初步的实验支持。特别是，在129Sv的遗传背景下，p66shc缺陷小鼠的寿命大约延长了30%(平均寿命)。由于p66shc是哺乳动物中唯一被报道的突变，在没有多种内分泌干扰的情况下可能能够延长寿命，因此需要对缺乏p66shc的小鼠进行详细的表征。P66shc缺陷动物是本应用的重点，应该能够详细描述p66shc在长寿中的具体作用，它与ROS介导的衰老表型的关系，以及对p66shc在骨骼肌衰老中的作用的具体研究。我们期望这个动物模型将为研究氧化应激和细胞凋亡在衰老中的作用提供一个非常有价值的工具。老年率将在三个水平上进行评估：1)通过生存和疾病模式来评估生物水平；2)通过测量线粒体功能、氧化应激和骨骼肌中的细胞凋亡来评估生化和细胞水平；以及3)通过骨骼肌中的基因表达谱来评估转录水平。

DESCRIPTION (provided by applicant): Mice deficient for p66shc have been generated previously and shown to have extended lifespan in one particular strain background (Migliaccio et al., 1999). Because p66shc deficiency is one of the few genetic interventions reported to increase lifespan in a mammal, studies to understand how this pathway impacts lifespan have the potential to increase our understanding of aging mechanisms. We have used gene targeting to generate mice that lack p66shc. This animal model was generated by selectively deleting a region of exon 2 of the p66shc gene in embryonic stem (ES) cells. We propose to use the newly generated p66shc mice to conduct a detailed study of the role of p66shc on the aging process. The central hypothesis to be tested is that p66shc deficiency will retard the aging process, and that this effect is due to reduced ROS levels, maintenance of mitochondrial function and reduced ROS-induced apoptosis during aging in target tissues. Using skeletal muscle as a model, we will test if p66shc deficiency will prevent age-related mitochondrial dysfunction, apoptosis, and age-related transcriptional alterations. Further, we propose to determine the effect of p66shc mutation on lifespan and disease patterns in a long-lived mouse genetic background. A previous study has provided preliminary experimental support for an association between p66shc deficiency and retardation of the aging process. In particular, p66shc deficient mice were shown to live approximately 30% longer (average lifespan) in a 129Sv genetic background. Because p66shc is the only reported mutation in mammals that may be able to extend lifespan in the absence of multiple endocrine disruption, a detailed characterization of mice lacking p66shc is needed. p66shc deficient animals, which are the focus of this application, should allow detailed characterization of the specific role of p66shc in longevity, its relationship to ROS mediated aging phenotypes, and a specific examination of the role of p66shc in skeletal muscle aging. We expect that this animal model will provide an extremely valuable tool to investigate the role of oxidative stress and apoptosis in aging. Aging rates will be evaluated at three levels: 1) organismal level by survival and disease patterns; 2) biochemical and cellular level by measures of mitochondrial function, oxidative stress and apoptosis in skeletal muscle; and, 3) transcriptional level, through gene expression profiling in skeletal muscle.