Role of LKB1 and AMPK in Metformin and TZD Control of Glucose Metabolism in Liver

LKB1 和 AMPK 在二甲双胍和 TZD 控制肝脏葡萄糖代谢中的作用

基本信息

批准号：
7883224
负责人：
Reuben Shaw
金额：
$ 34.37万
依托单位：
SALK INSTITUTE FOR BIOLOGICAL STUDIES
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-09-30 至 2012-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7883224
关键词：
2,4-thiazolidinedione 5&apos -AMP-activated protein kinase Adenovirus Vector Adult Amino Acid Sequence Antibodies Biochemical Biochemistry Bioinformatics Blood Glucose Catalytic Domain Cell Line Cells Consensus Defect Development Diabetes Mellitus Effectiveness Exercise Future Genes Genetic Gluconeogenesis Glucose Hepatic Hepatocyte Homeostasis Knockout Mice Knowledge Left Lipids Liver Mammalian Cell Mediating Metabolic Metabolism Metformin Methodology Modality Mus Mutagenesis Non-Insulin-Dependent Diabetes Mellitus Nutrient Pathway interactions Peripheral Phenotype Phosphorylation Phosphotransferases Physiology Protein-Serine-Threonine Kinases Proteins Proteomics RNA Interference Regulation Role STK11 gene Signal Pathway Signal Transduction Stimulus Therapeutic Thiazolidinediones Tissues Work adipokines adiponectin blood glucose regulation cell type design genetic analysis glucose metabolism hepatic gluconeogenesis hepatoma cell in vivo insulin sensitivity lipid biosynthesis lipid metabolism loss of function mouse model novel research study response sensor therapeutic target tool upstream kinase

项目摘要

DESCRIPTION (provided by applicant): Deregulation of glucose and lipid metabolism in peripheral tissues is a hallmark of type 2 diabetes. AMP- activated protein kinase (AMPK) is a master regulator of cellular and organismal metabolism controlling glucose and lipid homeostasis. AMPK is activated by low nutrients, exercise, adipokines, and by the widely used diabetes therapeutics metformin and the thiazolidinediones (TZDs). In response to these stimuli, AMPK acts in the liver to reduce gluconeogenesis and lipogenesis through poorly understood mechanisms. We, and others, identified the serine/threonine kinase LKB1 as the critical upstream kinase mediating AMPK activation. We subsequently created a genetic deletion of LKB1 in the liver of adult mice, which resulted in complete loss of hepatic AMPK activity and dramatically increased gluconeogenesis and hepatic lipid accumulation. Using these mice, we demonstrated that LKB1 was required in liver for metformin to lower blood glucose levels, the first genetic proof of a specific pathway being required for the therapeutic action of metformin. The next big question is to understand how metformin impinges on LKB1/AMPK signaling and how they in turn regulate glucose metabolism. We propose to determine the role of LKB1 and AMPK in the control of hepatic glucose metabolism and in the therapeutic action of metformin and TZDs. First, as LKB1 is known to activate 12 AMPK-related kinases in addition to AMPK, we will determine whether loss of AMPK alone mimics the effects of loss of LKB1 on glucose metabolism and the response to metformin or TZDs. To this end, we will conditionally delete LKB1 or both catalytic AMPK1 genes in the liver of adult mice. Second, using hepatocytes derived from these mice and RNAi, we will define the critical upstream and downstream components of the LKB1/AMPK pathway required for the regulation of specific metabolic processes. Finally, we will identify a number of new effectors of AMPK that control metabolism using a combination of unique proteomic approaches to purify novel AMPK substrates in addition to transcriptional profiling in our genetically defined cells following metformin or TZD treatment. These studies will better illuminate the mechanism of action of these two widely used type 2 diabetes modalities, as well as identifying many new targets for the development of future therapeutics.

描述（由申请人提供）：外周组织中葡萄糖和脂质代谢失调是 2 型糖尿病的标志。 AMP 激活蛋白激酶 (AMPK) 是控制葡萄糖和脂质稳态的细胞和有机体代谢的主要调节剂。 AMPK 会被低营养、运动、脂肪因子以及广泛使用的糖尿病治疗药物二甲双胍和噻唑烷二酮类 (TZD) 激活。为了响应这些刺激，AMPK 在肝脏中发挥作用，通过鲜为人知的机制减少糖异生和脂肪生成。我们和其他人确定丝氨酸/苏氨酸激酶 LKB1 是介导 AMPK 激活的关键上游激酶。随后，我们在成年小鼠的肝脏中对 LKB1 进行了基因删除，导致肝脏 AMPK 活性完全丧失，并显着增加糖异生和肝脏脂质积累。使用这些小鼠，我们证明二甲双胍降低血糖水平需要肝脏中的 LKB1，这是二甲双胍治疗作用所需的特定途径的第一个遗传证据。下一个大问题是了解二甲双胍如何影响 LKB1/AMPK 信号传导以及它们反过来如何调节葡萄糖代谢。我们建议确定 LKB1 和 AMPK 在控制肝葡萄糖代谢以及二甲双胍和 TZD 治疗作用中的作用。首先，由于已知除了 AMPK 之外，LKB1 还能激活 12 种 AMPK 相关激酶，因此我们将确定单独的 AMPK 缺失是否会模拟 LKB1 缺失对葡萄糖代谢的影响以及对二甲双胍或 TZD 的反应。为此，我们将有条件地删除成年小鼠肝脏中的LKB1或两个催化AMPK1基因。其次，利用这些小鼠的肝细胞和 RNAi，我们将定义调节特定代谢过程所需的 LKB1/AMPK 途径的关键上游和下游组件。最后，除了在二甲双胍或 TZD 治疗后在我们的基因定义细胞中进行转录分析外，我们还将使用独特的蛋白质组学方法组合来纯化新的 AMPK 底物，从而鉴定出许多控制代谢的新 AMPK 效应子。这些研究将更好地阐明这两种广泛使用的 2 型糖尿病治疗方式的作用机制，并为未来治疗方法的开发确定许多新靶点。