Interaction of Genotype and Level of Dietary Restriction on Lifespan and Aging

在过去的三十年里，饮食限制（DR）已经成为“黄金标准”， 比较延缓衰老的方法。由于DR已被证明可以延长广泛的 从无脊椎动物到啮齿动物，DR被视为一种普遍的衰老干预措施。 然而，最近的一项研究表明，动物的基因型是一个主要的决定因素的能力， 动物对DR作出反应，例如，在研究的41个重组近交系小鼠中，有三分之二没有 当喂食40%的DR时（比喂食AD的小鼠少40%的饮食）， 自由采食）。这项研究的总体目标是利用基因型和DR水平之间的相互作用， 九个遗传多样的RI系小鼠。我们假设，DR将增加寿命和延缓衰老， 所有基因型;然而，DR的作用将是基因型和剂量依赖性的，即，一个级别的 DR并非对所有基因型都是最佳的。这项研究的全面设计，使我们第一次能够 准确了解遗传多样性如何影响DR对寿命和衰老的影响。 具体目标1：确定DR是否以基因型和剂量依赖性方式影响寿命。的 将对9个RI系的雌性小鼠的寿命进行喂养，这些雌性小鼠显示出对40%DR的响应的最大多样性。 自由采食或比自由采食的每个RI系消耗的量少10、20或40%的饮食。基于我们 假设，我们预测，所有九个RI线将显示寿命的增加;然而，限制的水平， 增加寿命所必需的基因型会因基因型而异。 具体目标2：确定DR是否以基因型和剂量依赖性方式影响生命末期病理学。 方式由于减少大多数年龄相关的病理是DR的标志性特征，我们将进行一项 Aim 1中死亡的所有雌性小鼠的综合病理学分析。我们预测， DR的寿命将伴随着大多数与年龄相关的病理性病变的减少/延迟， 支持DR通过延缓老化来延长寿命的前提。我们还预测，DR对 生命末期的病理损伤将是基因型和DR剂量依赖性的。 具体目标3：确定DR抗衰老机制中的潜在途径。 测量从喂食AL和三种DR的小鼠的肝脏和附睾脂肪中分离的RNA中的转录物水平 使用Illumina小鼠微阵列进行12个月的饮食。利用我们微阵列数据的无偏分析， 我们将确定DR显著改变的途径，因为我们将在27 喂养DR的小鼠队列（喂养10、20和40%DR的9个小鼠品系），我们处于独特的位置来识别 具有最大预测能力的基因谱，以识别显示出显著差异的小鼠队列。 增加寿命时，放置在DR饮食，并从这些数据，我们可以确定潜在的机制，关键 在延长生命的行动博士。

Over the past three decades, dietary restriction (DR) has become the "gold standard" against which manipulations that retard aging are compared. Because DR has been shown to increase the lifespan of a wide variety of organisms ranging from invertebrates to rodents, DR is viewed as a universal aging intervention. However, a recent study suggests that the genotype of an animal is a major determinant in the ability of the animal to respond to DR, e.g., two-thirds of the 41 recombinant inbred (RI) lines of mice studied either did not respond or showed reduced lifespan when fed 40% DR (40% less diet than that consumed by mice fed ad libitum). The overall goal of this grant is to explore the interaction between genotype and the level of DR using nine genetically diverse RI lines of mice. We hypothesize that DR will increase lifespan and delay aging in all genotypes; however, the effect of DR will be both genotype- and dose-dependent, i.e., one level of DR is not optimal for all genotypes. The comprehensive design of this study, allows us for the first time to obtain an accurate view of how genetic diversity impacts the effect of DR on lifespan and aging. Specific Aim 1: To determine whether DR affects lifespan in a genotype- and dose-dependent manner. The lifespans of nine RI lines of female mice that show maximum diversity in response to 40% DR will be fed ad libitum or 10, 20, or 40% less diet than the amount consumed by each RI line fed ad libitum. Based on our hypothesis, we predict that all nine RI lines will show an increase in lifespan; however, the level of restriction necessary to obtain an increase in lifespan will vary with genotype. Specific Aim 2: To determine whether DR affects end-of-life pathology in a genotype- and dose-dependent manner. Because a reduction in most age-related pathologies is a hallmark feature of DR, we will conduct a comprehensive pathological analysis of all the female mice that die in Aim 1. We predict that the increase in lifespan by DR will be accompanied by a reduction/delay in most age-related pathological lesions, which would support the premise that DR increases lifespan by retarding aging. We also predict that the effect of DR on end-of-life pathological lesions will be genotype- and DR dose-dependent. Specific Aim 3: To identify potential pathways involved in the anti-aging mechanism of DR. We will measure the levels of transcripts in RNA isolated from liver and epididymal fat of mice fed AL and the three DR diets for 12 months using Illumina Mouse microarrays. Employing unbiased analyses of our microarray data, we will identify pathways that are altered significantly by DR. Because we will have transcriptome data on 27 cohorts of mice fed DR (nine strains of mice fed 10, 20, and 40% DR), we are in a unique position to identify gene profiles that have the greatest predictive power to identify the cohorts of mice that show a significant increase in lifespan when placed on a DR diet, and from these data, we can identify potential mechanisms key in the life-extending action DR.