The Role of Myc in ChREBP-dependent, Glucose-stimulated Gene Expression

Myc 在 ChREBP 依赖性、葡萄糖刺激的基因表达中的作用

基本信息

批准号：
8791682
负责人：
DONALD K. SCOTT
金额：
$ 30.42万
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：
2012
资助国家：
美国
起止时间：
2012-10-01 至 2016-01-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8791682
关键词：
Binding Binding Proteins Carbohydrates Cell Nucleus Cells ChIP-on-chip ChIP-seq Complex Data Diabetes Mellitus Disease Environment Epigenetic Process Event Failure Fasting Gene Expression Gene Expression Profile Gene Targeting Genes Genetic Transcription Glucose Glycolysis Hepatic Insulin Resistance Lipids Liver Malignant Neoplasms Measures Mediating Metabolic Metabolic Diseases Metabolic syndrome Metabolism Molecular Molecular Conformation Nucleic Acid Regulatory Sequences Perception Phenotype Physiological Play Polymerase Post-Translational Protein Processing Process Proteomics Publishing Pyruvate Kinase Recruitment Activity Response Elements Reverse Transcriptase Polymerase Chain Reaction Role Structure of beta Cell of islet Testing Tissues Transactivation Transcriptional Activation Warburg Effect Work activating transcription factor blood glucose regulation c-myc Genes cell growth regulation chromatin immunoprecipitation detection of nutrient domain mapping feeding glucose output glucose tolerance in vivo insight ketogenesis lipid biosynthesis oxidation prevent promoter response therapy design transcription factor

项目摘要

DESCRIPTION (provided by applicant): The ability of cells to sense and respond to changes in their metabolic environment is crucial to preventing the pathophysiological consequences of metabolic syndrome and diabetes. Cellular adaptation to changes in metabolic fuel availability includes coordinated changes in patterns of gene expression, mediated by nutrient- sensing transcription factors, and this process is disrupted in diabetes, with cells trapped in the fasted state despite abundant metabolic fuel. The purpose of the present proposal is to understand the relationship between two transcription factors involved in nutrient sensing and the hepatic fasted-to-fed transition, the glucose-sensing transcription factor carbohydrate response element binding protein (ChREBP), and Myc. ChREBP mediates transcriptional activation of glucose-responsive target genes in metabolically relevant tissues such as the liver and pancreatic beta cells. Glucose stimulates translocation of ChREBP to the nucleus, and once ChREBP is bound to target genes, additional poorly defined molecular events, dependent on glucose, must take place for transactivation. Dysregulated Myc, and recently ChREBP, have both been implicated in the increased glycolysis (Warburg effect) associated with transformation in cancer. Our published and Preliminary Data demonstrate that Myc is required for ChREBP-dependent glucose-stimulated gene expression, is recruited to regulatory regions of glucose-responsive genes, and is necessary for the recruitment of ChREBP and other activating transcription factors of the glucose response. We hypothesize that Myc works in a larger context to allow transition between metabolic phenotypes, e.g., the fasted and fed states. Our challenge, reflected in this proposal is to understand more completely the molecular relationship between Myc and ChREBP within the context of the physiological roles they play in glucose homeostasis, so that we can better understand how to manipulate them therapeutically in disease states. Our overarching hypothesis is that Myc is required for the ChREBP-dependent glucose response, and for transitions between metabolic phenotypes. Specific Aim 1) is to determine the physiological, metabolic, and molecular consequences of depleting Myc activity in the liver. Using a CRE-Lox approach, we will determine the effect of hepatic Myc depletion on the fasting-to-fed transition by measuring gene expression with RT-PCR and SOLID SAGE; by measuring ChREBP and other transcription factor occupancies by ChIP and by ChIP-seq; and by measuring glycolysis, lipogenesis, lipid storage and oxidation, ketogenesis, and glucose output, as well as whole body and hepatic insulin resistance and glucose tolerance. Specific Aim 2 is to determine how Myc promotes ChREBP-dependent glucose-activated gene transcription. We will use a proteomic approach to test if glucose alters the posttranslational modification of Myc; we will determine if Myc alters the epigenetic environment of glucose responsive genes in a glucose-dependent manner; and will map the domains of Myc required for the glucose-specific functions of Myc. Accomplishing these Aims will provide the framework for understanding the normal physiological relationship between Myc and ChREBP, and will allow informed design of therapies for metabolic disorders such as metabolic syndrome and diabetes, and may well provide insights towards the metabolic perturbations of cancer.

描述（由申请人提供）：细胞感知和应对其代谢环境变化的能力对于防止代谢综合征和糖尿病的病理生理后果至关重要。细胞对代谢燃料可用性变化的适应性包括基因表达模式的协调变化，是由营养感应转录因子介导的，尽管代谢燃料丰富，但在糖尿病中破坏了这种过程，细胞仍处于禁食状态。本建议的目的是了解养分感应涉及的两个转录因子与肝禁食到喂养的过渡，葡萄糖感应转录因子碳水化合物响应元件结合蛋白（CHREBP）和MYC之间的关系。 Chrebp介导了代谢相关组织（例如肝脏和胰腺β细胞）中葡萄糖反应性靶基因的转录激活。葡萄糖会刺激Chrebp转移到细胞核，一旦Chrebp与靶基因结合，必须进行反式激活的额外定义较差的分子事件，取决于葡萄糖。失调的MYC和最近的Chrebp都与与癌症转化相关的糖酵解（Warburg效应）的增加有关。我们发表的初步数据表明，MYC是Chrebp依赖性葡萄糖刺激的基因表达所必需的，被募集到葡萄糖响应基因的调节区域，对于募集CHREBP和葡萄糖反应的其他激活转录因子是必不可少的。我们假设MYC在更大的环境中起作用，以允许代谢表型（例如禁食状态和饲养状态）之间的过渡。在本提案中反映的我们的挑战是在它们在葡萄糖稳态中发挥的生理作用的背景下，更完全了解MYC和Chrebp之间的分子关系，以便我们可以更好地了解如何在疾病状态下对它们进行治疗。我们的总体假设是MYC是依赖Chrebp的葡萄糖反应以及代谢表型之间的过渡所必需的。具体目的1）是确定肝脏中MYC活性耗尽的生理，代谢和分子后果。使用CRE-LOX方法，我们将通过用RT-PCR和固体鼠尾草测量基因表达来确定肝MYC耗竭对禁食到喂养过渡的影响；通过测量CHIP和CHIP-SEQ的CHREBP和其他转录因子占用；通过测量糖酵解，脂肪生成，脂质储存和氧化，生酮发生和葡萄糖输出，以及全身和肝胰岛素抵抗和葡萄糖耐受性。具体目标2是确定MYC如何促进Chrebp依赖性葡萄糖激活的基因转录。我们将使用蛋白质组学方法来测试葡萄糖是否改变了MYC的翻译后修饰；我们将确定MYC是否以葡萄糖依赖性方式改变了葡萄糖反应基因的表观遗传环境。并将绘制MYC葡萄糖特异性功能所需的MYC域。实现这些目标将为理解MYC和Chrebp之间的正常生理关系提供框架，并将允许对代谢疾病（例如代谢综合征和糖尿病）的疗法进行明智的设计，并可以很好地提供对癌症代谢扰动的见解。