Comparative analysis of IGF-1 and mTOR signaling in short- and long-lived rodents

 描述（由申请方提供）：拟定研究的长期目标是了解决定寿命的分子机制。动物物种的衰老速度差别很大。因此，比较方法是一个强有力的工具，以获得新的见解老化的机制。营养感应IGF-1和mTOR通路在衰老中起主要作用。这RFA呼吁分析的作用，这些保守的营养传感途径发挥调节寿命在更广泛的脊椎动物物种。在本申请中，我们提出了识别短寿命和长寿命啮齿动物物种之间IGF-1和mTOR通路的差异。啮齿动物是这项研究的理想物种组，因为它包括具有不同寿命的遗传相关物种，其中缓慢衰老已经独立进化了几次。我们有独特的能力进行拟议的研究。我们的实验室已经收集了来自18种啮齿动物的原代细胞和组织，并对这些物种中的IGF-1信号进行了初步分析。我们的初步数据表明，IGF-1 R水平与长寿啮齿动物脑组织中的寿命呈负相关，而不是在外周组织中。拟议的研究将在一组18种不同寿命的啮齿动物中对IGF-1和mTOR信号进行系统分析。我们将解决以下问题：IGF-1和mTOR信号是否与物种间水平的寿命相关？自然选择是否使用下调这些信号通路作为进化更长寿命的一种方式，或者可以延长单个物种寿命的机制与进化规模上使用的机制有根本不同？哪些组织是重要的？在本申请中，我们将采用原代啮齿动物细胞和组织的收集来（1）进行IGF-1途径的比较分析;和（2）进行mTOR途径的比较分析。我们将研究这些途径的基础活性水平的差异，以及刺激后反应的强度和动力学。然后，我们将统计评估IFG-1和mTOR通路活性与寿命之间的关系。将校正数据的系统发育非独立性，并控制混杂变量，如身体大小。在接下来的三年里，当我们收集的物种的完整转录组序列将通过正在进行的资助合作变得可用时，我们将使用当前试点研究的信息，通过质谱法对这些途径进行蛋白质组学分析。这项拟议的研究将确定IGF-1和mTOR通路的活性与物种寿命之间是否存在相关性，并确定这些通路在长寿物种中下调的组织。这项工作对于理解长寿的进化至关重要。此外，如果对IGF-1和mTOR通路的下调至关重要的组织被鉴定，它们将被用作人类干预的靶点。

 DESCRIPTION (provided by applicant): The long-term goal of the proposed studies is to understand the molecular mechanisms that determine longevity. Animal species differ enormously in their aging rates. Therefore, comparative approach is a powerful tool to obtain new insights into the mechanisms of aging. The nutrient sensing IGF-1 and mTOR pathways play major roles in aging. This RFA calls for the analysis of the role these conserved nutrient sensing pathways play in regulating lifespan in a wider range of vertebrate species. In this application we propose to identify differences in IGF-1 and mTOR pathways between short-and long-lived species of rodents. Rodents are an ideal species group for this study as it includes phylogenetically related species with diverse lifespans, in which slow aging has evolved independently several times. We are uniquely equipped to carry out the proposed research. Our laboratory has assembled a collection of primary cells and tissues from 18 rodent species, and performed preliminary analysis of IGF-1 signaling in these species. Our preliminary data show that IGF-1R levels negatively correlate with lifespan in the brain tissue of long-lived rodents, bu not in the peripheral tissues. The proposed study will perform systematic analysis of IGF-1 and mTOR signaling in a panel of 18 rodent species with diverse lifespans. We will address the following questions: Does IGF-1 and mTOR signaling correlate with longevity at the interspecies level? Has natural selection used downregulating these signaling pathways as a way to evolve longer lifespan, or are the mechanisms that can extend lifespan of individual species fundamentally different from the mechanisms used on evolutionary scale? What tissues are important? In this application we will employ the collection of primary rodent cells and tissues to (1) Perform comparative analysis of the IGF-1 pathway; and (2) Perform comparative analysis of the mTOR pathway. We will examine the differences in the basal levels of activity of these pathways, and the strength and kinetics of the response upon stimulation. We will then statistically evaluate the relationship between the IFG-1 and mTOR pathway activity and lifespan. The data will be corrected for phylogenetic nonindependence, and controlled for confounding variables such as body size. In the next three years, when the complete transcriptome sequence of the species in our collection will become available, through the ongoing funded collaboration, we will use the information from the current pilot study to perform proteomics analysis of these pathways by mass spectrometry. The proposed study will determine whether there is a correlation between the activity of IGF-1 and mTOR pathways and longevity across species and identify the tissues in which these pathways are down-regulated in long-lived species. This work is essential for understanding evolution of longevity. Furthermore, if tissues critical for down-regulation of the IGF-1 and mTOR pathways are identified they will be used as targets for intervention in humans.