The Regulation of Hepatic Metabolic Zonation by the Diabetes Gene TCF7L2

糖尿病基因TCF7L2对肝脏代谢分区的调节

基本信息

批准号：
10369409
负责人：
Luke Norton
金额：
$ 44.09万
依托单位：
UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-01-01 至 2026-12-31
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10369409
关键词：
Address Adult Ammonia Architecture Biological Assay Candidate Disease Gene Catabolism Cell Nucleus Central Vein Chromatin Cirrhosis Clinical Couples Data Defect Development Diabetes Mellitus Disease Drug Metabolic Detoxication Enzymes Equilibrium Fibrosis Genes Genetic Polymorphism Genetic Transcription Genomics Glucose Glutamate-Ammonia Ligase Glutamates Glutamine HMG-Box Domains Hepatic Hepatocyte Homeostasis Human Link Lipids Liver Liver Fibrosis Liver diseases Lobular Lobule Maintenance Mediating Metabolic Metabolic Diseases Metabolic Pathway Metabolic dysfunction Metabolism Modeling Molecular Mus Non-Insulin-Dependent Diabetes Mellitus Pathologic Processes Pathway interactions Peripheral Physiological Play Population Portal triad Prevalence Primary carcinoma of the liver cells Proteins Public Health Publishing Regulation Rodent Rodent Model Role Signal Pathway Small Nuclear RNA TCF7L2 gene Techniques Testing Tissues Transcriptional Regulation Transposase amino acid metabolism base beta catenin design dietary experimental study fibrogenesis glucose metabolism hormone regulation human model in vivo lipid metabolism mouse model multiple omics non-alcoholic fatty liver disease nonalcoholic steatohepatitis novel spatiotemporal tool transcription factor transcriptome treatment strategy

项目摘要

ABSTRACT The mammalian liver consists of functional units called lobules, which are spatially separated into zones relative to the portal triad and central vein. Each zone contains hepatocytes with distinct functions that differentially impact metabolic processes. This spatial division of labor in liver has been appreciated for decades, but the molecular and physiological determinants of metabolic zonation are poorly understood. Moreover, whether dis- ordered hepatic metabolic architecture plays a pathophysiological role in prevalent liver diseases remains un- clear. As part of our long-term effort to dissect the functional role of leading type 2 diabetes (T2D) candidate genes, we have identified the protein encoded by the transcription factor 7-like 2 (TCF7L2) gene as a key regu- lator of hepatic metabolic zonation. Leveraging a unique mouse model of TCF7L2 inactivation in liver and an integrative combination of cellular, genomic and in vivo physiological approaches, we will examine the regulation of metabolic zonation by TCF7L2, and will determine the significance of the zonated pathways regulated by TCF7L2 to the development of hepatic fibrosis in nonalcoholic steatohepatitis (NASH). In published studies, we unveiled a striking role for TCF7L2 in the transcriptional regulation of a diverse set of metabolic genes in hepato- cytes, including those involved in zonated pathways of glucose, lipid, and amino acid metabolism. In preliminary studies we discovered that the expression of the Tcf7l2 gene is ubiquitous across the liver lobule, but TCF7L2 transcriptional activity is highly restricted to a population of hepatocytes surrounding the central vein in adult mouse liver. These data, and additional preliminary studies, prompted us to develop a unique mouse model that expresses transcriptionally inactive TCF7L2 exclusively in the liver (Hep-TCF7L2ΔDBD). Using this model, in this proposal we will test the central hypothesis that TCF7L2 is an important regulator of hepatic metabolic zonation, and that TCF7L2-mediated disruption of pericentral amino acid metabolism predisposes Hep-TCF7L2ΔDBD mice to dietary induced fibrosis and NASH. In specific aim 1, we will dissect the spatiotemporal transcriptional function of TCF7L2 in liver using cutting-edge single-nuclei Assay for Transposase-Accessible Chromatin sequencing (snATAC-Seq) with snRNA-Seq in distinct hepatocyte populations across the mouse liver lobule. In Specific Aim 2, we will determine the role of TCF7L2 in the maintenance of hepatic metabolic zonation and will test the impact of TCF7L2 inactivation on the lobular distribution of pericentral and periportal hepatocyte populations in Hep- TCF7L2ΔDBD mice. Finally, in Specific Aim 3 we will link hepatic fibrosis disrupted zonal amino acid metabolism in Hep-TCF7L2ΔDBD mice using integrative in vivo physiological approaches. These experiments will dissect the molecular and physiological mechanisms by which TCF7L2 influences hepatic metabolic zonation, and will de- scribe the consequences of disordered hepatic organization on the development of metabolic diseases.

抽象的哺乳动物肝脏由称为小叶的功能单元组成，这些单元在空间上分为相对的区域每个区域都包含具有不同功能的肝细胞。肝脏的这种空间分工几十年来一直受到人们的重视，但代谢分区的分子和生理决定因素知之甚少。有序的肝脏代谢结构在流行的肝脏疾病中发挥病理生理学作用仍不清楚这是我们长期努力剖析主要 2 型糖尿病 (T2D) 候选者功能作用的一部分。基因，我们已经鉴定出转录因子 7-like 2 (TCF7L2) 基因编码的蛋白质是一个关键调节因子。利用肝脏中 TCF7L2 失活的独特小鼠模型和细胞、基因组和体内生理学方法的综合组合，我们将检查调控 TCF7L2 的代谢分区，并将确定由 TCF7L2 调节的分区途径的重要性 TCF7L2 与非酒精性脂肪性肝炎 (NASH) 肝纤维化的发展有关。揭示了 TCF7L2 在肝细胞中多种代谢基因的转录调控中的显着作用细胞，包括那些参与初步葡萄糖、脂质和氨基酸代谢途径的细胞。研究发现 Tcf7l2 基因的表达在肝小叶中普遍存在，但 TCF7L2 转录活性高度受限于成人中央静脉周围的肝细胞群这些数据和其他初步研究促使我们开发了一种独特的小鼠模型在此模型中，仅在肝脏中表达转录失活的 TCF7L2 (Hep-TCF7L2ΔDBD)。建议我们将测试TCF7L2是肝脏代谢分区的重要调节因子的中心假设， TCF7L2 介导的中枢周围氨基酸代谢破坏易诱发 Hep-TCF7L2ΔDBD 小鼠在具体目标 1 中，我们将剖析时空转录功能。使用尖端单核检测进行转座酶可及染色质测序，检测肝脏中的 TCF7L2 (snATAC-Seq) 与小鼠肝小叶不同肝细胞群中的 snRNA-Seq 相结合。 2、我们将确定TCF7L2在维持肝脏代谢分区中的作用并测试其影响 TCF7L2 失活对 Hep 中中央和门静脉周围肝细胞群小叶分布的影响最后，在特定目标 3 中，我们将肝纤维化破坏的区域氨基酸代谢联系起来。这些实验将在 Hep-TCF7L2ΔDBD 小鼠中使用综合体内生理方法进行剖析。 TCF7L2 影响肝脏代谢分区的分子和生理机制，并将去- 描述肝组织紊乱对代谢疾病发展的影响。