Maternal Obesity affects AMP-Kinase in Muscle Cell Differentiation

母亲肥胖影响肌细胞分化中的 AMP 激酶

• 批准号: 8306744
• 负责人: MIN DU
• 金额: $ 23.82万
• 依托单位: WASHINGTON STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-27 至 2015-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8306744
• 关键词: 5' -AMP-activated protein kinase; Acetylesterase; Activities of Daily Living; Adipocytes; Adult; Affect; Affinity; Aging; American; Antidiabetic Drugs; Attenuated; Barker Hypothesis; Birth; Catalytic Domain; Cell Differentiation process; Cells; Child; Country; Cultured Cells; Data; Development; Developmental Biology; Diabetes Mellitus; Diet; Down-Regulation; EP300 gene; Embryo; Energy Metabolism; Ensure; Environment; Epidemic; Event; Fatty acid glycerol esters; Fetal Development; Fetus; Fibroblasts; Fibrosis; Gene Expression; Glucose; Health; Histones; Impairment; Incidence; Insulin; Insulin Resistance; Intervention; Intramuscular; Knockout Mice; Knowledge; Laboratories; Life; Link; Location; Mediating; Mediator of activation protein; Mesenchymal; Mesenchymal Stem Cells; Messenger RNA; Metabolic; Metabolism; Metformin; Methodology; Molecular; Mus; Muscle; Muscle Cells; Muscle Development; Muscle Fibers; Muscle function; Neonatal; Non-Insulin-Dependent Diabetes Mellitus; Nuclear Receptors; Obese Mice; Obesity; Pathway interactions; Peripheral; Peroxisome Proliferator-Activated Receptors; Pharmaceutical Preparations; Phosphorylation; Physiological; Pregnant Women; Protein Isoforms; Proteins; Regulation; Role; Signal Pathway; Signal Transduction; Skeletal Muscle; Staging; Staining method; Stains; Stress; Teenagers; Testing; Tissues; Transforming Growth Factors; United States; Universities; Woman; Work; Wyoming; adenylate kinase; animal facility; attenuation; child bearing; clinical application; density; experience; fatty acid oxidation; fetal; fetal programming; fibrogenesis; glucose uptake; in vivo; laboratory facility; lipid biosynthesis; mouse model; muscle form; muscle strength; myogenesis; novel; offspring; paracrine; pregnant; prevent; public health relevance; stem cell differentiation; transcription factor

DESCRIPTION (provided by applicant): SIGNIFICANCE: 18-35% of pregnant American women are clinically obese, a condition which affects fetal development with long-term consequences for offspring health, including pre-disposition to obesity and type 2 diabetes (T2D). The underlying mechanisms remain poorly defined. RATIONALE: Skeletal muscle (SM) is a key tissue responsive to the oxidation of fatty acids and glucose, and its transition to insulin resistance (IR) precedes the onset of T2D. The fetal stage is crucial for SM development since there is no net increase in the number of SM fibers after birth. Our preliminary studies in fetal SM indicate that maternal obesity (MO) reduced AMP-activated protein kinase (AMPK) activity, and altered fetal SM development by enhancing intramuscular adipogenesis and fibrogenesis, both of which impair SM functions. Myocytes, adipocytes and fibroblasts in fetal SM are derived from mesenchymal stem cells (MSC). Our preliminary studies show that AMPK phosphorylates and enhances 2-catenin mediated signaling, a pathway promoting myogenesis. AMPK also phosphorylates p300, which is expected to impair its function as a co-activator, and p300 is a necessary co-activator for transcription factors regulating adipogenesis and fibrogenesis. AMPK catalytic subunit has two isoforms demonstrating slightly different roles in metabolism. CENTRAL HYPOTHESIS: MO inhibits AMPK, which reduces phosphorylation of 2-catenin and p300 by AMPK, leads to the down-regulation of 2-catenin but enhancement of p300 mediated signaling and a shift from myogenesis to adipogenesis/fibrogenesis during fetal SM development. We have three SPECIFIC AIMS: 1) Evaluate whether 2-catenin is the key mediator linking AMPK to myogenesis in fetal SM; 2) Examine the link between p300 phosphorylation by AMPK and adipogenesis/fibrogenesis in fetal SM; 3) Assess the isoform specific effect of AMPK on myogenesis, adipogenesis and fibrogenesis. APPROACH: We plan to use mouse mesenchymal C3H10T1/2 cells to assess whether p300 and 2-catenin are key mediators between AMPK and MSC differentiation in fetal SM. We will also use the well-established diet-induced obesity mouse model to induce MO and the available AMPK-isoform-specific knockout mice to evaluate the role of AMPK in fetal SM development. Important mediators of selected signaling pathways will be analyzed at both mRNA and protein levels, as well as their location by immunohistochemical staining in fetal SM. OBJECTIVE: The objective is to test the role of AMPK in fetal SM development due to MO and to further explore mechanisms. INNOVATION: We are pioneering studies to define the role of AMPK in fetal SM development. The proposed work is novel, because the effects of AMPK and its associated signaling pathways on fetal SM development due to MO are just becoming to be appreciated. ENVIRONMENT: All methodologies required are already established in our laboratory. The Developmental Biology Group and the Center for the Study of Fetal Programming provide excellent academic environment, and animal and laboratory facilities. IMPACT: Proposed studies will demonstrate AMPK as a key mediator of fetal SM development, which will make it possible to use numerous available anti- diabetic drugs, known activators of AMPK, to prevent impairment of fetal SM development due to MO. Data and knowledge obtained will also allow us to further explore mechanisms regulating fetal SM development due to other maternal physiological stresses. Given the importance of SM for lifelong activities and its close association with obesity and T2D, such intervention will help the increasing number of obese pregnant women in this country to deliver healthy children. PUBLIC HEALTH RELEVANCE: The United States is experiencing an obesity epidemic which increasingly involves women of child bearing years. 18-35% of pregnant American women are clinically obese, a condition which affects fetal development with long-term consequences for offspring health, including pre-disposition to obesity and Type 2 diabetes. The underlying mechanisms are poorly defined. The objectives of proposed studies are to explore mechanisms associated with impairment of fetal skeletal muscle development due to maternal obesity. Knowledge obtained will allow us to further explore fetal skeletal muscle development due to maternal obesity and other maternal physiological stresses. Molecular mediators identified are targets for interventions to ensure proper skeletal muscle development in fetuses of obese women. Due to the importance of skeletal muscle for lifelong activities and its close association with obesity and Type 2 diabetes, such intervention will help the increasing number of obese pregnant women in this country to deliver healthy children.

描述（由申请人提供）：意义：18-35%的美国孕妇临床肥胖，这种情况会影响胎儿发育，并对后代健康产生长期影响，包括肥胖和2型糖尿病（T2D）的易感性。潜在的机制仍然不明确。理由：骨骼肌（SM）是对脂肪酸和葡萄糖氧化反应的关键组织，其向胰岛素抵抗（IR）的转变先于T2D的发生。胎儿阶段对SM的发育至关重要，因为出生后SM纤维的数量没有净增加。我们对胎儿SM的初步研究表明，母亲肥胖（MO）降低了amp活化蛋白激酶（AMPK）的活性，并通过增强肌内脂肪生成和纤维生成来改变胎儿SM的发育，这两者都损害了SM的功能。胎儿SM的肌细胞、脂肪细胞和成纤维细胞来源于间充质干细胞（MSC）。我们的初步研究表明AMPK磷酸化并增强2-连环蛋白介导的信号传导，这是一种促进肌肉形成的途径。AMPK也会磷酸化p300，这可能会削弱其作为共激活因子的功能，而p300是调节脂肪形成和纤维形成的转录因子的必要共激活因子。AMPK催化亚基有两个同工异构体，在代谢中的作用略有不同。中心假说：MO抑制AMPK，从而降低AMPK对2-catenin和p300的磷酸化，导致2-catenin的下调，但p300介导的信号传导增强，并在胎儿SM发育过程中从肌肉形成向脂肪形成/纤维形成转变。我们有三个特定的目的：1)评估2-catenin是否是连接AMPK与胎儿SM肌发生的关键介质；2)研究胎儿SM中AMPK磷酸化p300与脂肪形成/纤维形成的关系；3)评估AMPK在肌生成、脂肪生成和纤维生成中的异构体特异性作用。方法：我们计划使用小鼠间充质C3H10T1/2细胞来评估p300和2-catenin是否是胎儿SM中AMPK和MSC分化的关键介质。我们还将使用完善的饮食诱导肥胖小鼠模型来诱导MO和现有的AMPK亚型特异性敲除小鼠来评估AMPK在胎儿SM发育中的作用。我们将从mRNA和蛋白水平分析所选信号通路的重要介质，并通过免疫组织化学染色分析其在胎儿SM中的位置。目的：检测AMPK在MO胎儿SM发育中的作用，并进一步探讨其机制。创新：我们正在进行开创性的研究，以确定AMPK在胎儿SM发育中的作用。这项工作是新颖的，因为AMPK及其相关信号通路对MO引起的胎儿SM发育的影响刚刚开始得到重视。环境：我们的实验室已经建立了所需的所有方法。发育生物学组和胎儿编程研究中心提供了良好的学术环境，以及动物和实验室设施。影响：拟议的研究将证明AMPK是胎儿SM发育的关键介质，这将使使用许多已知的AMPK激活剂的抗糖尿病药物来预防MO导致的胎儿SM发育损害成为可能。所获得的数据和知识也将使我们进一步探索由于其他母亲生理应激而调节胎儿SM发育的机制。鉴于SM对终生活动的重要性及其与肥胖和T2D的密切联系，这种干预将有助于该国越来越多的肥胖孕妇生育健康的孩子。