Translational regulation during cigarette smoking-induced reprogramming of the tRNA epitranscriptome, in vitro and in a mouse smoking model

1.项目总结 吸烟会导致心血管疾病、慢性阻塞性肺疾病(COPD)和肺 癌症。暴露于环境烟草烟雾(ETS)引起的疾病的病因学是由以下因素引起的 ETS作为&gt；4000化学物质的混合物的复杂性，包括直接作用和代谢激活 毒药。虽然所有生物体都通过调节基因表达来应对环境暴露，但我们知之甚少 关于将毒物暴露与细胞存活和疾病联系起来的翻译机制。在这里，我们试图 了解几十种修饰的核糖核苷在tRNA-tRNA表位转录组学中的作用 调节细胞对ETS暴露的反应。使用独特的计算和分析平台，我们拥有 结果表明：(1)毒物暴露会引起酵母和哺乳动物表位转录组的标志性变化 细胞，以及(2)毒物诱导的tRNA表位转录组重编程通过以下方式调节蛋白质水平 促进酵母应激反应基因家族中偏向密码子的mRNAs的选择性翻译。我们的 对细菌、酵母和哺乳动物细胞1-7的研究也表明，关键表位转录编写器的缺陷 酶使细胞对特定毒物的杀伤敏感，这是由于应激反应蛋白的翻译被破坏。 我们推测，暴露在ETS的复杂混合物中将重新编程tRNA表位转录编码组 以反映ETS中的主要化学应激源，以及改变的RNA修饰将调节 选择性翻译偏向密码子的应激反应mRNAs的细胞行为。为了支持这一点，我们有 药物和毒物染毒大鼠肝脏药物特异性表位转录组重编程的观察 (例如，砷；NTP DrugMatrix)，以及烷基化和氧化特异的签名tRNA修饰在 酵母和人类细胞。我们的表位转录编写器缺陷(Alkbh8-空)小鼠显示tRNA修饰 翻译氧化解毒硒蛋白所需的系统对暴露于 在ETS中，萘是一种P450活化的、产生氧化剂的多环芳烃(PAH)。三个目标 从培养的小鼠细胞的体外研究到小鼠ETS暴露模型，我们测试了这样的想法 表位转录和翻译调控在细胞对ETS的反应中起着重要作用。 好了！

1. PROJECT SUMMARY Cigarette smoking causes cardiovascular disease, chronic obstructive pulmonary disease (COPD), and lung cancer. The etiology of diseases caused by exposure to environmental tobacco smoke (ETS) is confounded by the complexity of ETS as a mixture of >4000 chemicals, including direct-acting and metabolically-activated toxicants. While all organisms respond to environmental exposures by regulating gene expression, we know little about the translational mechanisms linking toxicant exposure to cell survival and disease. Here we seek to understand the role of the dozens of modified ribonucleosides in tRNA – the tRNA epitranscriptome – in regulating the cell response to ETS exposure. Using a unique computational and analytical platform, we have shown that (1) toxicant exposures cause signature changes in the epitranscriptome of yeast and mammalian cells, and (2) that toxicant-induced reprogramming of the tRNA epitranscriptome regulates protein levels by promoting the selective translation of codon-biased mRNAs from families of stress-response genes in yeast. Our studies in bacteria, yeast and mammalian cells1-7 also show that deficiencies in key epitranscriptomic writer enzymes sensitize cells to killing by specific toxicants due to corrupted translation of stress response proteins. We hypothesize that exposure to the complex mixture of ETS will reprogram the tRNA epitranscriptome to reflect the predominant chemical stressors in ETS and that the altered RNA modifications will regulate cell behavior by selective translation of codon-biased stress response mRNAs. In support of this, we have observed agent-specific epitranscriptome reprogramming in the liver from rats exposed to drugs and toxicants (e.g., arsenic; NTP DrugMatrix), and alkylation- and oxidation-specific signature tRNA modification changes in yeast and human cells. Our epitranscriptomic writer-deficient (Alkbh8-null) mice showed that tRNA modification systems required for translating oxidant-detoxifying selenoproteins are vital to surviving exposure to naphthalene, a P450-activated, oxidant-generating, polycyclic aromatic hydrocarbon (PAH) in ETS. In three aims ranging from in vitro studies in cultured mouse cells to a mouse ETS exposure model, we test the idea that the epitranscriptome and translational regulation play an important role in the cell response to ETS. !