TOX4 integrates hormone signaling on hepatic glucose and lipid metabolism

TOX4 整合肝脏葡萄糖和脂质代谢的激素信号传导

基本信息

批准号：
10460521
负责人：
Liheng Wang
金额：
$ 13.1万
依托单位：
ICAHN SCHOOL OF MEDICINE AT MOUNT SINAI
依托单位国家：
美国
项目类别：
财政年份：
2019
资助国家：
美国
起止时间：
2019-09-04 至 2023-08-09
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10460521
关键词：
Ablation Adenoviruses Affinity Affinity Chromatography Albumins American Beta Cell Biological Assay Blood Glucose Breeding Chromatin DNA Data Diabetes Mellitus Diagnosis Diet Enzymes FOXO1A gene Failure Family Family member Fasting Gene Expression Genes Genetic Transcription Gluconeogenesis Glucose Hepatic Hepatocyte Heterogeneity High Fat Diet Hormones Hyperglycemia Impairment In Vitro Insulin Insulin Receptor Insulin Resistance Intervention Knock-out Knockout Mice Liver LoxP-flanked allele Mass Spectrum Analysis Mediating Medical Metabolic Metabolism Molecular Mus Non-Insulin-Dependent Diabetes Mellitus Pathologic Pathway interactions Phosphoenolpyruvate Carboxylase Physiological Physiology Play Post-Translational Protein Processing Prevention Process Proteins Regulation Research Resistance Role Sampling Testing Transcription Coactivator Transcriptional Regulation Transposase blood glucose regulation db/db mouse diabetic diet-induced obesity glucose metabolism glucose production glucose tolerance glucose-6-phosphatase glycogenolysis hormonal signals improved in vivo insulin regulation insulin sensitivity knock-down lipid biosynthesis lipid metabolism member metabolic abnormality assessment novel novel therapeutic intervention oxidation prevent promoter response small hairpin RNA success therapeutic target transcription factor transcriptome sequencing

项目摘要

Project Summary One in every 10 Americans is diagnosed with diabetes, and 90% of them have type 2 diabetes (T2D) due to insulin resistance and beta cell failure. Prevention and treatment of T2D remain an unmet medical need. The liver produces glucose during fasting to maintain normal blood glucose levels. This process is dysregulated in T2D, when resistance to or lack of insulin increases glucose production, resulting in hyperglycemia and its complications. Insulin regulation of hepatocyte glucose production (HGP) requires rapid changes in gene expression. FoxO1 plays an essential role in the transcriptional regulation of HGP. FoxO1 ablation impairs, but does not completely abolish the regulation of glucose production by insulin, likely due to incomplete suppression of phosphoenolpyruvate carboxykinase (Pck1) gene expression. These data highlight the heterogeneity of transcription factors (TFs) in regulating glucose production. The PI has recently identified TOX High Mobility Group Box Family Member 4 (TOX4) as a novel insulin-regulated TF, using DNA affinity purification from the Pck1 promoter and mass spectrometry (MS) in primary hepatocytes and liver samples. However, the metabolic function of TOX4 is unknown. In preliminary data, she shows that TOX4 is a transcriptional activator of Pck1 and glucose-6-phosphatase (G6pc). Knockdown of Tox4 in primary hepatocytes reduces glucose production by repressing these two genes. Moreover, in vivo KD of Tox4 in liver using adenovirus-encoded shRNA significantly inhibits gluconeogenesis and improves glucose tolerance and insulin sensitivity in C57BL/6J mice, while simultaneously promoting lipogenesis. These changes are more pronounced in diet-induced-obese (DIO) and diabetic db/db mice. Therefore, she hypothesizes that TOX4 regulates glucose and lipid metabolism in response to hormones. In this application, she will generate mice to ablate TOX4 in hepatocytes and critically investigate the function of TOX4 in hepatic glucose and lipid metabolism (Aim 1). She will further examine the mechanisms underlying hepatic TOX4 activation and regulation of its downstream targets (Aim 2). Successful completion of this application will illustrate the role of a new TF in regulating glucose and lipid metabolism in the liver in response to insulin. More importantly, these proposed studies will determine whether TOX4 is a potential therapeutic target in the treatment of insulin resistance and T2D.

项目概要每 10 个美国人中就有 1 人被诊断患有糖尿病，其中 90% 的人患有 2 型糖尿病 (T2D)，原因是胰岛素抵抗和β细胞衰竭。 T2D 的预防和治疗仍然是一个未得到满足的医疗需求。这肝脏在禁食期间产生葡萄糖以维持正常的血糖水平。这个过程是失调的 T2D，当胰岛素抵抗或缺乏胰岛素增加葡萄糖产生时，导致高血糖及其并发症。肝细胞葡萄糖产生（HGP）的胰岛素调节需要基因的快速改变表达。 FoxO1 在 HGP 的转录调控中发挥重要作用。 FoxO1 消融会产生损害，但是并没有完全废除胰岛素对葡萄糖产生的调节，可能是由于不完全抑制磷酸烯醇丙酮酸羧激酶 (Pck1) 基因表达。这些数据突显了转录因子（TF）在调节葡萄糖产生中的异质性。 PI 最近发现了 TOX High Mobility Group Box Family Member 4 (TOX4) 作为一种新型胰岛素调节 TF，利用 DNA 亲和力从原代肝细胞和肝脏样品中的 Pck1 启动子和质谱 (MS) 中进行纯化。然而，TOX4的代谢功能尚不清楚。在初步数据中，她表明 TOX4 是一种 Pck1 和葡萄糖 6 磷酸酶 (G6pc) 的转录激活剂。原代细胞中 Tox4 的敲低肝细胞通过抑制这两个基因来减少葡萄糖的产生。此外，Tox4 在肝脏中的体内 KD 使用腺病毒编码的 shRNA 显着抑制糖异生并改善葡萄糖耐量 C57BL/6J 小鼠的胰岛素敏感性，同时促进脂肪生成。这些变化更多的是在饮食诱导肥胖 (DIO) 和糖尿病 db/db 小鼠中显着。因此，她推测 TOX4 响应激素调节葡萄糖和脂质代谢。在这个应用程序中，她将生成老鼠消除肝细胞中的 TOX4 并严格研究 TOX4 在肝葡萄糖和脂质中的功能新陈代谢（目标 1）。她将进一步研究肝脏 TOX4 激活的机制和对其下游目标的监管（目标 2）。成功完成此申请将说明一种新的转录因子，可响应胰岛素调节肝脏中的葡萄糖和脂质代谢。更重要的是，这些拟议的研究将确定 TOX4 是否是胰岛素治疗的潜在治疗靶点抵抗力和 T2D。