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

• 批准号: 8098166
• 负责人: Reuben Shaw
• 金额: $ 34.03万
• 依托单位: SALK INSTITUTE FOR BIOLOGICAL STUDIES
• 依托单位国家: 美国
• 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/8098166
• 关键词: 2,4-thiazolidinedione; 5' -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

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激活的蛋白激酶（AMPK）是细胞和生物体代谢的主要调节剂，控制葡萄糖和脂质的稳态。AMPK被低营养、运动、脂肪因子以及广泛使用的糖尿病治疗剂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，通过人们知之甚少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LKB 1是介导AMPK活化的关键上游激酶。随后，我们在成年小鼠的肝脏中创建了LKB 1的遗传缺失，这导致肝脏AMPK活性完全丧失，并显着增加了肝脏脂质蓄积。使用这些小鼠，我们证明了二甲双胍在肝脏中需要LKB 1来降低血糖水平，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LKB 1/AMPK信号传导，以及它们如何反过来调节葡萄糖代谢。 我们建议确定LKB 1和AMPK在控制肝脏葡萄糖代谢和二甲双胍和TZDs的治疗作用中的作用。首先，由于已知LKB 1除了AMPK外还激活12种AMPK相关激酶，我们将确定AMPK单独缺失是否模拟LKB 1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LKB 1或两种催化AMPK 1基因。其次，使用来自这些小鼠的肝细胞和RNAi，我们将确定LKB 1/AMPK途径的关键上游和下游组分，这些组分是调节特定代谢过程所需的。最后，我们将确定一些新的AMPK效应物，这些效应物控制代谢，使用独特的蛋白质组学方法的组合来纯化新型AMPK底物，以及二甲双胍或TZD治疗后我们遗传定义的细胞中的转录谱。这些研究将更好地阐明这两种广泛使用的2型糖尿病模式的作用机制，并为未来治疗方法的开发确定许多新的靶点。