Translational regulation in exposure biology: Xenobiotic-induced reprograming oftRNA modifications and selective translation of codon-biased response genes in rat and humanmodels

暴露生物学中的翻译调控：大鼠和人类模型中异生素诱导的 tRNA 修饰重编程和密码子偏向反应基因的选择性翻译

• 批准号: 9769034
• 负责人: Thomas J Begley
• 金额: $ 33.3万
• 依托单位: STATE UNIVERSITY OF NEW YORK AT ALBANY
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-09-01 至 2021-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9769034
• 关键词: Acute; Alkylating Agents; Animals; Arsenic; Arsenites; Biology; Cells; Cellular Stress; Codon Nucleotides; Collaborations; Complex; DNA Adducts; Data; Diethylnitrosamine; Disease; Distant; Dose; Drug Exposure; Enzymes; Eukaryota; Exposure to; Family; Formaldehyde; Foundations; Future; Gamma Rays; Gene Expression; Gene Expression Regulation; Gene Family; Genes; Goals; Hepatocyte; Human; Hydrogen Peroxide; In Vitro; Inflammatory; Inhalation; Link; Liver; Lung; Mammalian Cell; Mammals; Messenger RNA; Mesylates; Modeling; Modification; Nasal Epithelium; National Institute of Environmental Health Sciences; National Toxicology Program; Nitrosoguanidines; Nose; Oxidants; Oxidative Stress; Paraquat; Pattern; Peroxonitrite; Pharmaceutical Preparations; Phenotype; Play; Proteins; Proteomics; Publishing; RNA; Rattus; Reporter; Research Institute; Ribonucleosides; Rodent Model; Role; Signal Transduction; Statistical Data Interpretation; Stimulus; Stress; System; Testing; Tissues; Toxicant exposure; Transcript; Transcriptional Regulation; Transfer RNA; Translating; Translational Regulation; Translations; Vitamin K 3; Work; Xenobiotics; Yeasts; base; biological adaptation to stress; cigarette smoking; exposed human population; human data; in vivo; insight; mouse model; novel; programs; public health relevance; respiratory; response; tRNA Methyltransferases; tert-Butylhydroperoxide; toxicant

 DESCRIPTION (provided by applicant): The goal of this project is to explore a new systems-level mechanism by which cells respond to stresses and exposures by regulating translation. Cells respond to xenobiotic exposures by linking external stimuli to changes in cell phenotype through signal transduction, transcriptional regulation, and protein 2° modifications. Using a unique computational and analytical platform, we recently discovered a new mechanism of translational control of the cell stress response in yeast, in which toxicant-induced reprogramming of dozens of modified ribonucleosides in tRNA regulates protein levels by promoting the selective translation of codon-biased mRNAs representing families of stress-response genes. The goal of the proposed studies is to test the hypothesis that translational regulation of gene expression by stress-specific coordinated changes in the dozens of tRNA modifications plays a role in the response of cells and tissues to xenobiotic exposure in mammals. Abundant preliminary data in rat and mouse models, including tissue from the National Toxicology Program's DrugMatrix, supports this hypothesis, with strong evidence that xenobiotic- induced changes in tRNA modifications, as well as enzymes that modify tRNA, are essential regulators of stress responses in complex tissues. Here we will use human cell and rat exposure models to firmly place tRNA reprogramming as a translational regulator of the response to xenobiotics. Specifically, we hypothesize that exposure to xenobiotics promotes toxicant-specific changes in tRNA modification patterns, and that the reprogrammed tRNAs regulate protein levels by way of selective translation of codon-biased stress response transcripts. We will test these hypotheses in two aims. Aim 1 focuses on in vitro analysis of tRNA reprogramming and proteomic changes in human lung and liver cells exposed to a battery of alkylating and oxidizing agents that overlap with our published yeast exposure results. This provides a systematic comparison of yeast and mammalian cell responses. Aim 2 moves the in vitro studies of Aim 1 to the in vivo setting to test the hypothesis that the translational respons mechanism occurs in complex tissues. We first build on preliminary studies of arsenite exposure in rats using tissues from the NTP DrugMatrix to define the link between tRNA reprogramming and codon-biased translation with iTRAQ proteomics. We then test the translational control model in rats exposed to inhaled formaldehyde in collaboration with Drs. Melanie Doyle- Eisele and Ben Moeller (Lovelace Resp. Res. Inst.) and Jim Swenberg (UNC). We previously showed that pulmonary exposure to formaldehyde generates protein and DNA adducts in nasal epithelium but not more distant lung and liver tissues, so we anticipate seeing formaldehyde-induced tRNA reprogramming and codon- biased translation in nasal tissue but not lung or liver, with nasal tissue matching the in vitro studies of Aim 1. These studies will provide critical insights into a novel mechanism of cell response to xenobiotic stress with direct relevance to human exposures. Future studies will translate this model to human drug exposures and inflammatory diseases.

 描述（由申请人提供）：该项目的目标是探索一种新的系统级机制，细胞通过调节翻译来响应压力和暴露。细胞通过信号转导、转录调节和蛋白质 2° 修饰将外部刺激与细胞表型的变化联系起来，从而对外源物暴露做出反应。利用独特的计算和分析平台，我们最近发现了一种酵母细胞应激反应翻译控制的新机制，其中毒物诱导的 tRNA 中数十种修饰核糖核苷的重编程通过促进代表应激反应基因家族的密码子偏向 mRNA 的选择性翻译来调节蛋白质水平。拟议研究的目的是检验以下假设：通过数十个 tRNA 修饰的应激特异性协调变化对基因表达的翻译调节在哺乳动物细胞和组织对外源性暴露的反应中发挥作用。大鼠和小鼠模型（包括来自国家毒理学计划的 DrugMatrix 的组织）的大量初步数据支持了这一假设，并有强有力的证据表明，外源性物质诱导的 tRNA 修饰变化以及修饰 tRNA 的酶是复杂组织中应激反应的重要调节因子。在这里，我们将使用人类细胞和大鼠暴露模型来牢固地将 tRNA 重编程作为对外源性物质反应的翻译调节因子。具体来说，我们假设接触异生物质会促进 tRNA 修饰模式中毒物特异性的变化，并且重编程的 tRNA 通过选择性翻译偏向密码子的应激反应转录本来调节蛋白质水平。我们将在两个目标上检验这些假设。目标 1 重点关注接触一系列烷基化剂和氧化剂的人肺和肝细胞中 tRNA 重编程和蛋白质组变化的体外分析，这与我们发表的酵母暴露结果重叠。这提供了酵母和哺乳动物细胞反应的系统比较。目标 2 将目标 1 的体外研究转移到体内环境，以检验翻译响应机制发生在复杂组织中的假设。我们首先使用 NTP DrugMatrix 组织对大鼠亚砷酸盐暴露进行初步研究，以确定 tRNA 重编程和 iTRAQ 蛋白质组学密码子偏倚翻译之间的联系。然后，我们与 Drs 合作，在暴露于吸入甲醛的大鼠中测试了转化控制模型。 Melanie Doyle-Eisele 和 Ben Moeller（Lovelace Resp. Res. Inst.）和 Jim Swenberg（北卡罗来纳大学）。我们之前表明，肺部接触甲醛会在鼻上皮中产生蛋白质和 DNA 加合物，但不会在更远的肺和肝组织中产生蛋白质和 DNA 加合物，因此我们预计在鼻组织中而不是肺或肝中看到甲醛诱导的 tRNA 重编程和密码子偏向翻译，鼻组织与目标 1 的体外研究相匹配。这些研究将为新的研究提供重要见解。 细胞对外源胁迫反应的机制与人类暴露直接相关。未来的研究将将该模型转化为人类药物暴露和炎症性疾病。