Mechanisms of Obesity-Induced Genetic Instability at Endogenous Mutation Hotspots

肥胖引起的内源突变热点遗传不稳定性的机制

基本信息

批准号：
10311484
负责人：
John DiGiovanni
金额：
$ 42.71万
依托单位：
UNIVERSITY OF TEXAS AT AUSTIN
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-01-01 至 2023-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10311484
关键词：
Acute Adopted Animals B-Cell Lymphomas B-DNA Biological Assay Bone Marrow Burkitt Lymphoma Caloric Restriction Cancer Etiology DNA DNA Damage DNA Mutational Analysis DNA Repair DNA Repair Pathway DNA Sequence DNA Sequence Alteration DNA Structure DNA biosynthesis Data Development Diet Double Strand Break Repair Down-Regulation Gamma-H2AX Gender Generations Genetic Genome Genome Stability Genomic Instability Goals Guanine H-DNA Human Impairment Knowledge Lead Link Liver Malignant Neoplasms Mammals Maps Measures Mus Mutagenesis Mutation Nonhomologous DNA End Joining Obese Mice Obesity Obesity associated cancer Organism Oxidative Stress Pathway interactions Play Predisposition Prevention Process Public Health RTH-1 Nuclease Refractory Reporter Research Risk Factors Role Sampling Spleen Structure Testing Thymus Gland Time Tissues Transgenic Mice Transgenic Organisms Translocation Breakpoint Work Z-Form DNA c-myc Genes cancer genome cancer risk diet-induced obesity dietary dietary control dietary restriction energy balance experimental study genome integrity genomic tools homologous recombination in vivo leukemia/lymphoma mammalian genome mouse model novel novel strategies obesity risk obesity treatment oxidative DNA damage prevent public health relevance repaired response tool transcriptome sequencing

项目摘要

PROJECT SUMMARY The overall objective of this proposal is to understand how dietary energy balance and especially obesity influences genome stability at endogenous mutation “hotspots”. To achieve this objective, we will use novel mouse models that we have developed to determine the impact of obesity on DNA structure-induced mutagenesis in various tissues from these mice. Repetitive DNA sequences are widely dispersed throughout mammalian genomes and can adopt alternative (non-B DNA) secondary structures, such as H-DNA and Z- DNA. Importantly, these non-B DNA structure-forming sequences are significantly enriched at endogenous mutation hotspots in human cancer genomes, implicating them in cancer etiology. For example, H-DNA- forming sequences in the c-MYC gene are found at translocation breakage hotspots in Burkitt’s lymphoma and acute B-cell lymphoma. We have developed novel mutation-reporter mice containing human H-DNA- and Z- DNA-forming sequences that co-localize with translocation breakpoint hotspots, and demonstrated for the first time that these sequences are mutagenic in vivo. Obesity is known to increase cellular oxidative stress and oxidative DNA damage, whereas calorie restriction has been shown to decrease cellular oxidative stress, oxidative DNA damage, reduce mutagenesis and to enhance DNA repair pathways. In addition, obesity is an important risk factor for a significant number of cancers. However, the extent to which dietary energy balance and especially obesity influences DNA structure-induced genetic instability is not known. Thus, a goal of the proposed work is to fill this gap in knowledge. In this proposal, we will test the working hypothesis that obesity increases DNA structure-induced genetic instability. We will examine the impact of diet-induced obesity and calorie restriction on DNA structure-induced mutagenesis in mice. Several different tissues will be evaluated from these mice to determine whether there are any tissue specific differences in mutagenesis in response to energy balance manipulation. We will also explore mechanisms for the impact of obesity on DNA structure- induced genetic instability. We will focus our studies on the impact of obesity on DNA repair mechanisms as several recent studies have suggested that obesity impairs multiple DNA repair pathways, including non- homologous end-joining, a repair pathway that we have found to play a role in the processing of non-B DNA. In addition, we have found that flap endonuclease 1 (FEN1) plays an important role in error-free processing of non-B DNA and that its levels are modulated by dietary energy balance. These observations will also be explored in more detail in this proposal. Completion of the proposed studies will lead to a greater understanding of how obesity influences cancer etiology. In addition, this work will lead to the identification of novel targets for the prevention and/or treatment of obesity-related cancers.

项目概要该提案的总体目标是了解膳食能量平衡，尤其是肥胖如何平衡影响内源突变“热点”的基因组稳定性为了实现这一目标，我们将使用新颖的方法。我们开发的小鼠模型是为了确定肥胖对 DNA 结构诱导的影响这些小鼠的各个组织中的重复 DNA 序列广泛分布在各处。哺乳动物基因组，可以采用替代（非 B DNA）二级结构，例如 H-DNA 和 Z-DNA 重要的是，这些非 B DNA 结构形成序列在内源性中显着富集。人类癌症基因组中的突变热点，与癌症病因学有关，例如 H-DNA-。 c-MYC 基因中的形成序列发现于伯基特淋巴瘤的易位断裂热点处，我们开发了含有人类 H-DNA 和 Z- 的新型突变报告小鼠。与易位断点热点共定位的 DNA 形成序列，并首次得到证实已知肥胖会增加细胞氧化应激和体内诱变。氧化 DNA 损伤，而热量限制已被证明可以减少细胞氧化应激，氧化 DNA 损伤、减少突变并增强 DNA 修复途径。然而，膳食能量平衡的程度是许多癌症的重要危险因素。尤其是肥胖对DNA结构引起的遗传不稳定性的影响尚不清楚。因此，该研究的目标尚不清楚。拟议的工作是为了填补这一知识空白。在本提案中，我们将测试肥胖这一工作假设。增加DNA结构引起的遗传不稳定性我们将研究饮食引起的肥胖的影响和将评估热量限制对小鼠 DNA 结构诱导突变的影响。从这些小鼠中确定是否存在响应诱变的任何组织特异性差异我们还将探索肥胖对 DNA 结构影响的机制 - 我们将重点研究肥胖对 DNA 修复机制的影响。最近的几项研究表明，肥胖会损害多种 DNA 修复途径，包括非同源末端连接，我们发现它在非 B DNA 加工中发挥作用的修复途径。此外，我们发现瓣核酸内切酶 1 (FEN1) 在无差错处理中发挥着重要作用非 B DNA 及其水平受饮食能量平衡的调节。本提案中进行了更详细的探讨，完成拟议的研究将带来更大的成果。了解肥胖如何影响癌症病因此外，这项工作将有助于识别肥胖。预防和/或治疗肥胖相关癌症的新靶点。