Role of epigenetic crosstalks in directing locus sensitivity to arsenic

表观遗传串扰在引导基因座对砷的敏感性中的作用

基本信息

批准号：
10608433
负责人：
Patrick Allard
金额：
$ 53.47万
依托单位：
UNIVERSITY OF CALIFORNIA LOS ANGELES
依托单位国家：
美国
项目类别：
财政年份：
2023
资助国家：
美国
起止时间：
2023-01-25 至 2027-10-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10608433
关键词：
Arsenic Automobile Driving DNA DNA Methylation DNA Transposable Elements Data Deposition Environment Environmental Exposure Environmental Impact Epigenetic Process Exposure to Gene Silencing Genes Genetic Transcription Germ Cells Goals Health Histones Human Hypermethylation In Vitro Intercistronic Region Intracisternal A-Particle Elements Mediating Metabolic Metabolism Methyltransferase Modeling Molecular Mus Organ Pathway interactions Poison Predisposition Repetitive Sequence Repression Research Role Structure of primordial sex cell Testing Toxic Environmental Substances Untranslated RNA Work bisulfite sequencing body system embryonic stem cell environmental chemical environmental chemical exposure epigenetic regulation epigenome genome-wide genomic locus histone methylation histone modification in vivo knock-down metabolomics overexpression response sodium arsenite stem cell differentiation toxicant transcriptome sequencing whole genome

Arsenic Automobile Driving DNA DNA Methylation DNA Transposable Elements Data Deposition Environment Environmental Exposure Environmental Impact Epigenetic Process Exposure to Gene Silencing Genes Genetic Transcription Germ Cells Goals Health Histones Human Hypermethylation In Vitro Intercistronic Region Intracisternal A-Particle Elements Mediating Metabolic Metabolism Methyltransferase Modeling Molecular Mus Organ Pathway interactions Poison Predisposition Repetitive Sequence Repression Research Role Structure of primordial sex cell Testing Toxic Environmental Substances Untranslated RNA Work bisulfite sequencing body system embryonic stem cell environmental chemical environmental chemical exposure epigenetic regulation epigenome genome-wide genomic locus histone methylation histone modification in vivo knock-down metabolomics overexpression response sodium arsenite stem cell differentiation toxicant transcriptome sequencing whole genome

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项目摘要

PROJECT SUMMARY The overarching goal of the research presented in this application is to understand what make some genomic loci more susceptible than others to environmental chemical perturbation. Using inorganic arsenic (iAs) as a model environmental toxicant of high human relevance, we will seek to mechanistically investigate how epigenetic crosstalks dictate locus-specific sensitivity to arsenic. iAs is a model epigenetic toxicant owing to its well described impact on global DNA hypomethylation coinciding with a reduction in the levels of the universal methyl donor SAM, used towards DNA and histone methylation. However, this model of epigenetic mechanism of iAs has been acknowledged as largely unsatisfactory since (1) even in the context of global DNA hypomethylation, some loci show hypermethylation while others show no change, and (2) the effect on histone methylation are non-uniform with many methylated histone marks showing increases while others show a decrease. Here, we propose to build on compelling preliminary data obtained through highly quantitative Mass Spec and metabolomic studies that show that in mouse ESCs, at levels where sodium arsenite does not cause a significant increase in ROS levels, a pronounced decrease in SAM, DNA methylation, and in several histone marks, such as H3K36me2/3, are observed. However, H3K27me3 levels are increased while H3K9me3 levels are unchanged. Furthermore, RNA-seq studies revealed even in the context of profound transcriptional changes, repetitive elements that are repressed by deposition of H3K9me3 remain transcriptionally silenced following sodium arsenite exposure. Thus, we hypothesize that epigenetic crosstalks can differentially compete for the reduced SAM pool caused by iAs exposure, thereby driving locus sensitivity. To test this hypothesis, we will use mouse ESCs where crosstalks are well characterized. In aim 1, we will characterize the genome-wide changes in DNA methylation and in 3 distinct histone PTMs. We will also test whether these epigenetic alterations caused by iAs require the metabolic activity of the arsenic methyltransferase AS3MT. In aim 2, we will use a combination of knock-down, over-expression, and profiling approaches to mechanistically interrogate in the context of arsenic exposure the role of the well-characterized crosstalks between DNA methylation and histone PTMs at distinct genomic loci. Finally, in aim 3, we will examine the reprogrammability of arsenic-induced epigenetic alterations as ESCs are differentiated into early stage germ cells and go through profound waves of epigenetic remodeling. At the completion of these aims, we will have established the comprehensive profile of changes in DNA methylation and 4 histone PTMs following arsenic exposure. We will also have determined how epigenetic crosstalks mediate locus-specific sensitivity to arsenic and their ability to be reprogrammed in PGCs. This work will firmly establish the central role of epigenetic crosstalks in the response to environmental insults.

项目摘要本应用程序中提出的研究的总体目标是了解什么使某些基因组基因座比其他对环境化学化学扰动更容易受到影响。使用无机砷（IAS）作为高度人类相关性的模型环境毒物，我们将寻求机械化研究表观遗传串扰如何决定基因座特异性对砷的敏感性。 IAS是一种模型表观遗传学有毒物，由于其对全局DNA低甲基化的影响很好与通用甲基供体SAM的水平降低，用于DNA和组蛋白甲基化。但是，这种IAS的表观遗传机制模型已被公认为很大程度上不令人满意虽然其他人没有变化，并且（2）对组蛋白甲基化的影响是不均匀的，许多甲基化组蛋白标记显示增加，而其他人则显示下降。在这里，我们建议以引人注目的通过高度定量的质量规格和代谢组学研究获得的初步数据，该研究表明小鼠ESC，在砷钠不会导致ROS水平显着增加的水平，A SAM，DNA甲基化和几个组蛋白标记（例如H3K36ME2/3）的明显降低为观察到。但是，H3K27ME3水平升高，而H3K9ME3水平不变。此外， RNA-seq研究甚至在深刻的转录变化，重复元素的背景下揭示了通过沉积H3K9me3的沉积抑制，砷矿暴露后仍在转录沉默。因此，我们假设表观遗传串扰可以差异地竞争减少的SAM池由IAS暴露引起，从而推动基因座敏感性。为了检验这一假设，我们将使用鼠标ESC在串扰良好表征的情况下使用鼠标ESC。在AIM 1中，我们将表征全基因组甲基化和3个不同组蛋白PTM的全基因组变化。我们还将测试 IAS引起的这些表观遗传改变是否需要砷的代谢活性甲基转移酶AS3MT。在AIM 2中，我们将使用敲门，过表达和分析的组合在砷暴露的背景下，机械学询问的方法在不同基因组基因座的DNA甲基化和组蛋白PTM之间的串扰。最后，在AIM 3中，我们将随着ESC分化为早期阶段生殖细胞并经过深刻的表观遗传重塑。这些目标完成时，我们将建立DNA变化的全面概况砷暴露后的甲基化和4个组蛋白PTM。我们还将确定表观遗传串扰介导了对砷的特异性敏感性及其在PGC中重编程的能力。这项工作将牢固确定表观遗传串扰在对环境侮辱的反应中的核心作用。