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

描述（由申请人提供）：在过去的三十年里，饮食限制（DR）已成为“黄金标准”，与之相比，延缓衰老的操作。由于DR已被证明可以延长从无脊椎动物到啮齿动物的各种生物体的寿命，因此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，动物的基因型是动物对DR应答能力的主要决定因素，例如，所研究的41个重组近交系（RI）小鼠中有三分之二在喂食40%DR（比随意喂食的小鼠少40%的饮食）时没有反应或显示寿命缩短。这项资助的总体目标是使用9种遗传多样的RI系小鼠探索基因型和DR水平之间的相互作用。我们假设DR将增加所有基因型的寿命并延缓衰老;然而，DR的作用将是基因型和剂量依赖性的，即，一种DR水平并不是对所有基因型都是最佳的。这项研究的全面设计使我们首次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。对40%DR反应表现出最大多样性的雌性小鼠的9个RI系的寿命将被随意喂食或比每个RI系随意喂食消耗的量少10、20或40%的饮食。根据我们的假设，我们预测所有九条RI线都将显示出增加， 然而，获得寿命增加所需的限制水平将因基因型而异。 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。由于大多数年龄相关病理的减少是DR的标志性特征，因此我们将对Aim 1中死亡的所有雌性小鼠进行全面的病理分析。我们预测，DR增加寿命将伴随着大多数年龄相关的病理性病变的减少/延迟，这将支持DR通过延缓衰老增加寿命的前提。我们还预测，DR对临终病理病变的影响将是基因型和DR剂量依赖性的。 具体目标3：为了确定参与DR抗衰老机制的潜在途径，我们将使用Illumina小鼠微阵列测量从喂食AL和三种DR饮食12个月的小鼠的肝脏和附睾脂肪中分离的RNA中的转录水平。利用我们的微阵列数据的无偏分析，我们将确定DR显著改变的途径。（喂食10、20和40%DR的9种小鼠），我们处于一个独特的位置，可以识别出具有最大预测能力的基因谱，以识别出在以下情况下显示出寿命显著增加的小鼠群体：根据这些数据，我们可以确定延长DR寿命的潜在机制。

DESCRIPTION (provided by applicant): 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.