Intergenerational Arsenic Exposure on Mouse Epigenetics

代际砷暴露对小鼠表观遗传学的影响

• 批准号: 10217041
• 负责人: Mathia L Colwell
• 金额: $ 1.29万
• 依托单位: UNIVERSITY OF MINNESOTA
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-12-01 至 2022-03-13
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10217041
• 关键词: Adolescent; Adult; Adult Children; Affect; Age; Arsenic; Attenuated; Biosensor; Body Composition; Body Weight; Cardiovascular Diseases; Cicatrix; Color; Control Groups; Critical Thinking; Cytosine; DNA Markers; DNA Methylation; DNA Transposons; Development; Disease; Ectoderm; Embryo; Embryonic Development; Endoderm; Epigenetic Process; Event; Exposure to; Fatty acid glycerol esters; Female; Fetal Development; Functional disorder; Gametogenesis; Gene Expression Regulation; Generations; Genes; Germ; Germ Layers; Glucose tolerance test; Goals; Guidelines; Health; Heavy Metals; Human; Individual; Late-Onset Disorder; Life; Longevity; Malignant Neoplasms; Measurement; Measures; Mesoderm; Metabolic; Metal exposure; Methods; Methylation; Modeling; Modification; Mus; National Institute of Environmental Health Sciences; Non-Insulin-Dependent Diabetes Mellitus; Obesity; Onset of illness; Oocytes; Outcome Measure; Pathway interactions; Persons; Phenotype; Population; Predisposition; Pregnancy; Regulatory Element; Reporting; Research; Risk; Rodent; S-Adenosylmethionine; Scientist; Site; Spermatocytes; Strategic Planning; Structure of primordial sex cell; Testing; Tissues; Toxic effect; Toxicant exposure; Toxicology; Weight Gain; biological research; contaminated drinking water; disease phenotype; drinking water; environmental change; environmental chemical exposure; epigenome; experimental study; fetal; glucose tolerance; impaired glucose tolerance; imprint; in utero; insight; intergenerational; liquid chromatography mass spectrometry; methyl group; methylation pattern; mouse model; neuronal cell body; obesity development; offspring; prenatal; pyrosequencing; skills; toxicant; treatment group; zygote

PROJECT SUMMARY: Inorganic Arsenic (iAs) is one of the largest toxic exposures to impact humanity worldwide, with over 140 million people exposed to iAs via contaminated drinking water. Exposure to iAs during pregnancy disrupts normal DNA methylation patterns in developing offspring and leads to the onset of adult diseases such as type II diabetes (T2D), cardiovascular disease, and cancers. More specifically, disruption during pregnancy attenuates the proper remodeling of the epigenome of the F1 developing offspring and potentially its F2 grand-offspring via disruption of fetal primordial germ cells (PGCs). However, there is a limited understanding between the correlation between the disease phenotype and methylation profile within the F1 offspring. Furthermore, we do not know whether iAs exposure alters epigenetic remodeling in F2 grand- offspring and if the F2 generation is also at risk for developing iAs associated diseases even without direct iAs exposure. Mechanistically, epigenetic reprogramming could be disrupted within the primordial germ cells, resulting in differential DNA methylation and detrimental metabolic health in F2 offspring. The mechanism is as follows: iAs is metabolized enzymatically by methylation, using S-adenosylmethionine (SAM) as a methyl group donor. SAM is also normally used in DNA methylation to maintain the epigenome via the enzymatic addition of a methyl group to unmodified cytosines. Thus, the competition of SAM for both methylation pathways results in methyl group deficiency leading to less iAs conversion (increased toxicity) and less DNA methylation (mis-regulation of gene expression). The central hypothesis is that intergenerational effects of in utero iAs exposure will impact the epigenetic profile and onset of disease phenotypes within F1 and F2 adult offspring, despite the life-long absence of direct arsenic exposure within these generations. Aim 1 will establish the effects of iAs on F1 epigenetic remodeling during embryogenesis, focusing on genes associated with development of obesity and T2D during adulthood. To confirm the maternal effect of iAs exposure on epigenetic remodeling, the validated Agouti Avy mouse model epigenetic biosensor will be used to indicate loss or gain of DNA methylation by shifting coat color. Aim 2 will characterize the F2 (adult grand-offspring) effects of arsenic exposure on epigenetic remodeling in F1 primordial germ cells. For both aims, global DNA methylation and hydroxymethylation will be quantified in somatic and germ tissues by liquid chromatography mass-spectrometry and site specific methylation by pyrosequencing. Glucose tolerance and body composition will be measured in adult F1 and F2 offspring as indications of disease present in adulthood. Collectively, these experiments will provide a better understanding of the effects of iAs heavy metal exposure on intergenerational epigenetics, the onset of adult disease in subsequent generations, and targets of multigenerational epigenetic reprogramming. This study responds to the NIEHS Strategic Plan goals, Goal 1 (Basic Biological Research), Goal 2 (Individual Susceptibility) Goal 4 (Exposome) and Goal 6 (Predictive Toxicology).

项目摘要：无机砷(IAS)是对人类影响最大的有毒物质之一 全世界有超过1.4亿人通过受污染的饮用水暴露于国际AS。暴露于国际会计准则 怀孕期间会扰乱发育中的后代的正常DNA甲基化模式，并导致 成人疾病，如II型糖尿病(T2D)、心血管疾病和癌症。更确切地说， 妊娠期间的破裂减弱了F1发育后代的表观基因组的适当重塑 并可能通过破坏胎儿原始生殖细胞(PGC)产生其F2代后代。然而，有一个 对疾病表型和甲基化状态之间的相关性的了解有限 F1的后代。此外，我们不知道IAS暴露是否改变了F2Grand的表观遗传重塑- 如果F2代即使没有直接的IAS，也有患IAS相关性疾病的风险 曝光。从机制上讲，表观遗传重新编程可能会在原始生殖细胞内被破坏， 导致F2后代不同的DNA甲基化和有害的代谢健康。其机制是 下同：免疫球蛋白的代谢是通过甲基化，使用S-腺苷蛋氨酸作为甲基 团体捐献者。SAM通常也用于DNA甲基化，通过酶来维持表观基因组 在未修饰的胞嘧啶中加甲基。因此，SAM对这两种甲基化的竞争 途径导致甲基缺乏，导致IAS转化减少(毒性增加)和DNA减少 甲基化(基因表达的错误调节)。中心假说是In的代际效应 子宫IAS暴露将影响F1和F2成人的表观遗传学特征和发病表型 后代，尽管在这些世代中终生没有直接接触砷。目标1将建立 IAS在胚胎发育过程中对F1表观遗传重塑的影响 肥胖和T2D在成年期的发展。确认IAS暴露对母体的影响 表观遗传重塑，验证的Agti Avy小鼠模型表观遗传生物传感器将用于指示丢失 或通过改变毛色获得DNA甲基化。目标2将描述F2(成年孙)效应 砷暴露对F1原始生殖细胞表观遗传重构的影响。对于这两个目标来说，全球DNA 体细胞和生殖细胞组织中的甲基化和羟甲基化将通过高效液相色谱定量 焦磷酸测序的质谱学和位点特异性甲基化。糖耐量与身体成分 将在成年F1和F2后代中进行测量，作为成年后存在的疾病的迹象。总而言之，这些 实验将更好地了解IAS重金属暴露对世代之间的影响 表观遗传学，成人疾病在后代中的发病，以及多代表观遗传学的目标 重新编程。这项研究响应了NIEHS战略计划目标1(基础生物学研究)， 目标2(个体易感性)、目标4(曝光体)和目标6(预测性毒理学)。