Xenobiotic-responsive hepatic long non-coding RNAs

7.项目摘要/摘要 许多工业化学品、环境污染物和其他外来化学品激活转录因子 属于核受体超家族，导致广泛的基因组、表观遗传学和 在肝脏和其他组织中扰乱关键生物途径和代谢过程的转录变化 纸巾。这些研究建议将重点放在肝核受体CAR(构成雄烷受体； NR1I3)，它被结构不同的外来化学物质激活，并调节数百个 编码蛋白质的基因对异体代谢、脂肪生成、葡萄糖等过程非常重要 动态平衡和炎症，并被认为是非酒精性脂肪性肝病的调节因素 (NAFLD)发展。我们已经发现CAR和其他异生反应的异生激动剂 受体诱导或抑制数百个富含核的长非编码RNA的转录 (LncRNAs)具有表观遗传和基因调控潜力，其中许多具有人类同源基因。这项建议 建立在这些发现和肝细胞分区、单细胞转录的最新进展的基础上 和基因共表达网络分析，以阐明在完整的小鼠肝脏模型中 外源性化学物所致脂肪性肝病的CAR反应基因。这项研究建议 验证一个假设，即一个CAR反应的lncRNA子集控制肝脏基因调控网络驱动 非酒精性脂肪性肝病及其下游病变，如脂肪和碳水化合物代谢等失调过程， 肝细胞类型特异性和肝小叶带依赖的肝脏结构和线粒体功能 举止。提出的工作使用了TCPOBOP(1，4-bis[2-(3，5-dichloro-pyridyloxy)]benzene)，，一个原型的非 遗传毒性化学物质和CAR特异性激动剂配体，以解决看似自相矛盾的发现 持续暴露于外来化学CAR激活剂可诱导喂食正常饮食的小鼠发生NAFLD，但 抑制喂食高脂饮食的小鼠的NAFLD发展。这些研究将阐明CAR的作用，以及 它调控的lncRNAs在脂肪肝的病因和进展中的作用。所获得的结果将给出关键的 国外化学物质扰乱依赖汽车的代谢的潜在机制 与NAFLD有关的途径，它影响着25%的美国成年人，是肝硬化、肝细胞癌的主要原因 癌症和肝功能衰竭。这项工作将重新将研究重点放在外来化学作用上，以包括机理 基于单细胞的、空间分区的基因调控网络和非编码转录组的研究， 并将作为其他外来化学激活受体的范例，这些受体可以失调基因表达 以复杂的方式。综上所述，对汽车反应的lncRNA及其在外来化学物质中的作用的拟议研究- 诱导肝病理可能为预防、诊断或治疗化学性肝病提供新的途径 曝光。

7. Project Summary/Abstract Many industrial chemicals, environmental pollutants and other xenochemicals activate transcription factors belonging to the nuclear receptor superfamily, which leads to widespread genomic, epigenetic and transcriptional changes that disrupt key biological pathways and metabolic processes in liver and other tissues. The studies proposed focus on the liver nuclear receptor CAR (Constitutive Androstane Receptor; NR1I3), which is activated by structurally diverse xenochemicals and regulates transcription of hundreds of protein-coding genes important for processes such as xenobiotic metabolism, lipogenesis, glucose homeostasis, and inflammation, and has been implicated as a regulator of non-alcoholic fatty liver disease (NAFLD) development. We have discovered that xenobiotic agonists of CAR and other xenobiotic-responsive receptors induce or repress the transcription of several hundred nuclear-enriched long non-coding RNAs (lncRNAs) with epigenetic and gene regulatory potential, many of which have human orthologs. This proposal builds on these findings and on recent advances in liver cell zonation, single cell-based transcriptomic profiling, and gene co-expression network analysis to elucidate in an intact mouse liver model the effects of CAR-responsive lncRNAs on fatty liver disease induced by foreign chemical exposure. The studies proposed test the hypothesis that a subset of CAR-responsive lncRNAs control hepatic gene regulatory networks driving NAFLD and downstream pathologies, dysregulating processes such as lipid and carbohydrate metabolism, hepatic architecture and mitochondrial function in a liver cell type-specific and hepatic lobule zone-dependent manner. The work proposed uses TCPOBOP (1,4-bis[2-(3,5-dichloro-pyridyloxy)]benzene), a prototypic non- genotoxic chemical and CAR-specific agonist ligand, to address the seemingly paradoxical finding that persistent exposure to foreign chemical CAR activators induces NAFLD in mice fed normal chow diet, but suppresses NAFLD development in mice fed a high fat diet. These studies will elucidate the role of CAR, and the lncRNAs that it regulates, in fatty liver disease etiology and progression. Results obtained will give critical insight into the underlying mechanisms by which foreign chemicals dysregulate CAR-dependent metabolic pathways linked to NAFLD, which affects 25% of US adults and is a major cause of cirrhosis, hepatocellular cancer and liver failure. This work will refocus research efforts on xenochemical action to include mechanistic studies of single cell-based, spatially zonated gene regulatory networks and the non-coding transcriptome, and will serve as a paradigm for other foreign chemical-activated receptors that dysregulate gene expression in complex ways. Together, the proposed studies on CAR-responsive lncRNAs and their role in xenochemical- induced liver pathology may lead to new ways to prevent, diagnose or treat liver diseases induced by chemical exposure.