LKB1- AMPK pathway regulation of glucose metabolism and metformin action in liver

LKB1- AMPK 通路对肝脏葡萄糖代谢和二甲双胍作用的调节

• 批准号: 8373413
• 负责人: Reuben Shaw
• 金额: $ 46.56万
• 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 2016-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8373413
• 关键词: 5' -AMP-activated protein kinase; Adult; Attenuated; Binding; Biochemical; Biochemistry; Blood Glucose; CREB1 gene; Catalytic Domain; Collaborations; Critical Pathways; Deacetylation; Diabetes Mellitus; Drug effect disorder; Euglycemic Clamping; Exercise; Family; Fasting; Fatty Liver; Funding; Future; Genes; Genetic; Glucagon; Gluconeogenesis; Glucose; Glucose Clamp; Goals; Grant; Growth; HDAC4 gene; HDAC5 gene; HDAC7 histone deacetylase; Hepatic; Histones; Homeostasis; Hormones; Individual; Knockout Mice; Laboratories; Lipids; Liver; Measures; Mediating; Metabolic; Metabolic Control; Metabolism; Metformin; Modality; Modeling; Molecular; Molecular Models; Mus; Non-Insulin-Dependent Diabetes Mellitus; Nuclear Import; Nutrient; Output; Pathway interactions; Peripheral; Pharmaceutical Preparations; Phenotype; Phosphorylation; Phosphotransferases; Physiology; Play; Protein Dephosphorylation; Protein Isoforms; Protein-Serine-Threonine Kinases; Raptors; Refractory; Regulation; Relative (related person); Reporting; Rodent; Role; STK11 gene; Signal Pathway; Signal Transduction; Therapeutic; Time; Tissues; Triglycerides; United States; United States National Institutes of Health; Universities; Work; adipokines; adiponectin; base; blood glucose regulation; defined contribution; glucose metabolism; glucose production; hepatic gluconeogenesis; improved; in vivo; insulin sensitivity; lipid biosynthesis; lipid metabolism; loss of function; molecular modeling; mouse model; next generation; novel; response; sensor; 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 which acts as sensor of cellular energy status and plays key roles in glucose and lipid homeostasis in metabolic tissues. AMPK is activated by low nutrients, exercise, adipokines such adiponectin, and by the widely used diabetes therapeutic metformin. Upon activation in liver, AMPK functions to reduce gluconeogenesis and lipogenesis through incompletely understood mechanisms. Previously, the serine/threonine kinase LKB1 was identified as the critical upstream kinase mediating AMPK activation in most mammalian tissues. Genetic deletion of LKB1 in the liver of adult mice resulted in complete loss of hepatic AMPK activity and significant increases in gluconeogenesis and hepatic lipid accumulation, while attenuating the ability of metformin to lower blood glucose. A major challenge in the field remained in decoding the molecular mechanisms through which LKB1-AMPK signaling controls metabolism. Over the past 4 years of this funding, my laboratory performed a multi-pronged screen for direct substrates of AMPK, which led to the identification and study of a number of novel AMPK substrates critical in metabolism, including Raptor, ULK1, Cry1, Srebp1, and HDACs4, 5, and 7. In this first renewal, it is proposed to further dissect the role of AMPK and related kinases in control of glucose metabolism and the therapeutic action of metformin. Given the recent advances in decoding the molecular effectors of the LKB1/AMPK signaling pathway, the relative contributions of different AMPK substrates to metabolic control and metformin's therapeutic action can now begin to be delineated. In Aim 1, the role of AMPKalpha1, AMPKalpha2, and the related SIK kinases will be compared in control of hepatic glucose metabolism using novel temporally controlled genetic mouse models. In Aim 2, we will utilize these models to define the relative requirement for LKB1 and AMPK isoforms in the therapeutic action of metformin in liver. A key aspect of this aim is a collaboration with Dr. Davi Wasserman at Vanderbilt University to define the effect of LKB1 and AMPK on metabolic flux in these models. Finally, in the Aim 3, we will expand on our recent discoveries by directly examining the relative roles of Class IIa HDAC-FOXO axis versus CRTC coactivators-CREB axis in the control of glucose homeostasis in liver. These studies disecting the role of the LKB1- AMPK pathway in liver will increase the understanding of how existing widely used diabetes modalities work, and identify critical new targets for future type 2 diabetes therapeutics. PUBLIC HEALTH RELEVANCE: Despite the fact metformin is the most widely used type 2 diabetes therapeutic in the world (>100 million users estimated), little is known about its mechanism of action. The proposed studies aim at determining how critical the activation of the AMPK signaling pathway by metformin is to this drug's action, and to decode which downstream AMPK substrates are critical for its beneficial effects on glucose and lipid metabolism. The proposed studies on how this key biochemical signaling pathway activated by metformin regulates glucose metabolism will increase our understanding of how this current modality works and will identify many additional targets for the next generation of type 2 diabetes 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活化蛋白激酶（AMPK）是细胞和生物体代谢的主要调节因子，作为细胞能量状态的传感器，在代谢组织中的糖和脂质稳态中起关键作用。AMPK被低营养、运动、脂肪因子如脂联素和广泛使用的糖尿病治疗剂二甲双胍激活。在肝脏中激活后，AMPK通过不完全理解的机制发挥减少脂肪生成和脂肪生成的作用。以前，丝氨酸/苏氨酸激酶LKB 1被确定为在大多数哺乳动物组织中介导AMPK活化的关键上游激酶。成年小鼠肝脏中LKB 1的遗传缺失导致肝脏AMPK活性完全丧失，并显著增加肝脏脂质生成和肝脏脂质蓄积，同时减弱二甲双胍降低血糖的能力。该领域的一个主要挑战仍然是解码LKB 1-AMPK信号控制代谢的分子机制。在过去4年的资助中，我的实验室对AMPK的直接底物进行了多管齐下的筛选，这导致了许多在代谢中至关重要的新型AMPK底物的鉴定和研究，包括Raptor，ULK 1，Cry 1，Srebp 1和HDACs 4，5和7。在第一次更新中，建议进一步剖析AMPK和相关激酶在控制葡萄糖代谢中的作用以及二甲双胍的治疗作用。 鉴于解码LKB 1/AMPK信号通路的分子效应物的最新进展，现在可以开始描绘不同AMPK底物对代谢控制和二甲双胍治疗作用的相对贡献。在目的1中，AMPKalpha 1、AMPKalpha 2和相关的SIK激酶的作用将使用新的时间控制遗传小鼠模型在控制肝脏葡萄糖代谢中进行比较。在目标2中，我们将利用这些模型来确定二甲双胍在肝脏中的治疗作用中对LKB 1和AMPK亚型的相对需求。这一目标的一个关键方面是与范德比尔特大学的Davi Wasserman博士合作，以确定LKB 1和AMPK对这些模型中代谢通量的影响。最后，在目标3中，我们将通过直接检查IIa类HDAC-FOXO轴与CRTC共激活物-CREB轴在肝脏葡萄糖稳态控制中的相对作用来扩展我们最近的发现。这些研究剖析了LKB 1- AMPK通路在肝脏中的作用，将增加对现有广泛使用的糖尿病模式如何工作的理解，并确定未来2型糖尿病治疗的关键新靶点。 公共卫生相关性：尽管二甲双胍是世界上使用最广泛的2型糖尿病治疗药物（估计使用者超过1亿），但对其作用机制知之甚少。拟议的研究旨在确定二甲双胍激活AMPK信号通路对该药物的作用有多重要，并解码哪些下游AMPK底物对其对葡萄糖和脂质代谢的有益作用至关重要。关于二甲双胍激活的这一关键生化信号通路如何调节葡萄糖代谢的拟议研究将增加我们对这种当前模式如何工作的理解，并将为下一代2型糖尿病治疗确定许多其他靶点。