Does Dietary Restriction Alter Stem Cell Function Through An Epigenetic Mechanism?

饮食限制是否通过表观遗传机制改变干细胞功能？

• 批准号: 9920075
• 负责人: WILLARD M FREEMAN
• 金额: $ 22.38万
• 依托单位: UNIVERSITY OF OKLAHOMA HLTH SCIENCES CTR
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2022-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9920075
• 关键词: Affect; Age; Aging; Animals; Biological Assay; Biological Markers; Cell physiology; Cells; Chromatin; Chronology; CpG Islands; Cytosine; DNA; DNA Methylation; DNA Modification Methylases; DNA-Binding Proteins; Data; Data Set; Disease; Enhancers; Epigenetic Process; Epithelial Cells; Equilibrium; Gene Expression; Genes; Genetic Transcription; Genome; Genomics; Goals; Grant; Human Genome; Intervention; Intestinal Mucosa; Intestines; Knowledge; Laboratories; Lead; Life; Longevity; Maintenance; Measures; Mediating; Memory; Methylation; Molecular; Mus; Nucleic Acid Regulatory Sequences; Organism; Pathway interactions; Play; Regulator Genes; Research; Resolution; Rodent; Role; Seminal; Signal Transduction; Site; Testing; Tissues; age effect; age related; anti aging; base; dietary restriction; healthspan; improved; insight; interest; mouse genome; next generation sequencing; novel; prevent; promoter; stem cells; transcription factor; transcriptome; transcriptome sequencing; transcriptomics

Of all the interventions that have been shown to increase lifespan, dietary restriction (DR) is the most studied and universal aging intervention. Because DR also delays the onset and progression of most age-related diseases as well as maintaining healthspan, it is well accepted that DR increases lifespan by delaying/retarding aging. However, we still do not understand the mechanism(s) responsible for the anti-aging effect of DR. An important aspect of DR that has been largely overlooked is that when implemented early in life DR can increase lifespan of rodents even when rodents are fed ad libitum (AL) the remainder of their life. This provides compelling evidence that DR acts through a mechanism that involves a molecular signal(s) that arises shortly after the implementation of DR and has an impact on the animal over its lifespan, even after DR is discontinued, e.g., an epigenetic mechanism, such as DNA methylation. Functionally, DNA methylation (5mC) can regulate chromatin status and affect the ability of transcription factors and other DNA binding proteins to access DNA and regulate gene expression, thereby altering the function of cells and tissues. Several groups, including our laboratories, have shown that DR alters DNA methylation in tissues of mice, reversing many of the changes in DNA methylation that occur with age as well as inducing changes in DNA methylation that do not change with age. Recently we found that short-term DR induces changes in DNA methylation in intestinal mucosa in the promoter of the Nts 1 gene. The changes in DNA methylation are closely associated with increased expression of Nts 1, which persist when the DR mice are then fed ad libitum for several months. Because the epithelial cells in the intestinal mucosa are continuously renewed every 4 to 5 days, the changes in DNA methylation we observed in intestinal mucosa most likely arise in intestinal stem cells. Therefore, we hypothesize that DR induces changes in DNA methylation in intestinal stem cells at specific genomic sites that results in a molecular memory, which potentially leads to alterations in the expression of genes that are important in intestinal stem cell function. In this project, we will measure changes in DNA methylation (5mC) and hydroxymethylation (5hmC) induced by DR in intestinal stem cells using a novel assay developed by our group, which allows us to measure accurately at single base resolution changes in both 5mC and 5hmC at ~ 30 million specific sites in the genome. In this R21 grant, we will test our hypothesis in the following specific aims. Aim 1: Determine the effect of DR on DNA methylation and hydroxymethylation across gene regulatory regions of the genome of stem cells isolated from the intestines of three groups of mice: mice fed AL, mice fed DR for 4 months, and DR mice fed DR for 4 months and then fed AL for 6 months. Aim 2: Identify changes in transcription that could arise from changes in DNA methylation/hydroxymethylation and play a role in intestinal stem cell function.

在所有已显示寿命增加的干预措施中，饮食限制（DR）是研究最多的 和普遍的衰老干预。因为DR还延迟了大多数与年龄有关的发作和进展 疾病以及维持健康范围的疾病，可以很好地接受DR通过延迟/延迟来增加寿命 老化。但是，我们仍然不了解导致DR的抗衰老作用的机制。一个重要的 DR的方面在很大程度上被忽视 啮齿动物的余生，即使在啮齿动物的剩余时间里也有啮齿动物。这提供了引人注目的 DR通过涉及分子信号的机制作用的证据 DR的实施，并对动物的寿命产生影响，即使DR终止之后，例如 表观遗传机制，例如DNA甲基化。在功能上，DNA甲基化（5MC）可以调节染色质 状态并影响转录因子和其他DNA结合蛋白访问DNA并调节的能力 基因表达，从而改变细胞和组织的功能。包括我们的实验室在内的几个小组 已经表明，DR会改变小鼠组织中的DNA甲基化，从而逆转DNA的许多变化 随着年龄的增长以及诱导不会随着年龄而变化的DNA甲基化的变化而发生的甲基化。 最近，我们发现短期DR诱导启动子肠粘膜中DNA甲基化的变化 NTS 1基因的DNA甲基化的变化与NTS 1的表达增加密切相关， 然后，当Dr小鼠随意喂食几个月时，这会持续。因为 每4至5天一次再续签肠粘膜，我们观察到的DNA甲基化的变化 肠粘膜很可能在肠道干细胞中出现。因此，我们假设DR引起了变化 在特定基因组部位的肠道干细胞中的DNA甲基化中，导致分子记忆 潜在地导致在肠道干细胞功能中重要的基因表达改变。在 该项目，我们将测量由DNA甲基化（5MC）和羟甲基（5HMC）的变化 使用我们的组开发的新颖测定的肠道干细胞中的DR，这使我们能够准确地测量 在单碱基分辨率下，基因组中约3000万个特定地点的5MC和5HMC的变化。在此R21中 格兰特（Grant），我们将在以下特定目标中检验我们的假设。 AIM 1：确定DR对基因调节区域跨基因调节区域的DNA甲基化和羟甲基的影响 从三组小鼠的肠道中分离出的干细胞的基因组：喂食的小鼠，喂养4的小鼠 几个月，小鼠喂了DR 4个月，然后喂了6个月。 AIM 2：确定DNA甲基化/羟甲基的变化可能引起的转录变化 并在肠道干细胞功能中起作用。