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：
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
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/8098166
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的管制是2型糖尿病的标志。 AMP激活的蛋白激酶（AMPK）是控制葡萄糖和脂质稳态的细胞和生物代谢的主要调节剂。 AMPK被低营养素，运动，脂肪因子以及广泛使用的糖尿病二甲双胍和噻唑烷二酮（TZDS）激活。针对这些刺激，AMPK在肝脏中起作用，可通过不理理解的机制来减少糖异生和脂肪生成。我们和其他人将丝氨酸/苏氨酸激酶LKB1鉴定为介导AMPK激活的关键上游激酶。随后，我们在成年小鼠的肝脏中产生了LKB1的遗传缺失，从而完全丧失了肝AMPK活性，并大大增加了糖异生和肝脂质积累。使用这些小鼠，我们证明了肝素需要LKB1以降低血糖水平，这是二甲双胍治疗作用所需的特定途径的第一个遗传证明。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的治疗作用中的作用。首先，由于LKB1还可以激活12个与AMPK相关的激酶，除了AMPK之外，我们还将确定单独的AMPK丢失是否模仿LKB1损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，使用源自这些小鼠和RNAi的肝细胞，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成分。最后，我们将确定AMPK的许多新效应因子，这些效应因素使用独特的蛋白质组学方法组合来控制代谢，以纯化新型AMPK底物，除了在二甲双胍或TZD处理后我们的遗传定义细胞中的转录分析外，除了转录分析外。这些研究将更好地阐明这两种广泛使用的2型糖尿病方式的作用机理，并确定许多新的未来治疗剂的目标。