Physiological Signals to MCT Expression

MCT 表达的生理信号

• 批准号: 7197266
• 负责人: GEORGE Austin BROOKS
• 金额: $ 30.76万
• 依托单位: UNIVERSITY OF CALIFORNIA BERKELEY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-15 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7197266
• 关键词: AICA ribonucleotide; Acetyl Coenzyme A; Address; Adenine Nucleotides; Affect; Anions; Arteries; Beds; Binding; Blood Circulation; Blood Glucose; Carbohydrates; Carbon; Carrier Proteins; Cell Line; Cell membrane; Cells; Charge; Chronic; Citric Acid Cycle; Cytosol; Electric Stimulation; Epinephrine; Exercise; Fiber; Generations; Genes; Genetic Transcription; Gluconeogenesis; Glucose; Glycogen; Glycolysis; Goals; Heart; Hormones; Human; In Vitro; Incubated; Kidney; Knowledge; Lactate Dehydrogenase; Link; Literature; Liver; Mediating; Membrane; Metabolic; Metabolism; Mitochondria; Modeling; Mus; Muscle; Muscle Cells; Muscle Fibers; Myosin ATPase; NADH; Nicotinamide adenine dinucleotide; Numbers; Operative Surgical Procedures; Organ; Oxidation-Reduction; Oxygenases; Pathway interactions; Physical activity; Physiological; Population; Potential Energy; Production; Protein Isoforms; Proteins; Publishing; Pyruvate; Pyruvates; Rate; Rattus; Reaction; Reactive Oxygen Species; Research Personnel; Rest; Rodent; Role; Sarcolemma; Signal Pathway; Signal Transduction; Site; Skeletal Muscle; Slow-Twitch Muscle Fibers; Stimulus; Time; Tissues; Training; Translations; Tumor Necrosis Factor-alpha; Tumor Necrosis Factors; Veins; Western Blotting; Work; adenylate; austin; base; concept; glycogenolysis; human TNF protein; in vivo; oxidation; peroxisome; programs; protein expression; pyruvate carrier; research study; response; tool; uptake

DESCRIPTION (provided by applicant): Lactate shuttling through the interstitium and vasculature provides a major means of distributing carbohydrate potential energy during exercise. Facilitated lactate exchange occurs between cells organs and tissues as well as between cell compartments by means of lactate, monocarboxylate transport (MCT) proteins. There exist tissue-specific differences in MCT expression and cell domains occupied by MCTs. In mammalian skeletal muscle, two isoforms (MCT1 and MCT4) are expressed. MCT1 exists in the sarcolemma and mitochondria and is associated with oxidative capacity, whereas MCT4 is in sarcolemma only and is higher in fibers with fast myosin isoforms. Muscle MCT1 protein level can be influenced by endurance training and chronic electrical stimulation in vivo, and with cultured L6 myotubes we have been able to affect MCT1 protein levels. Because little is known about the physiological signals affecting MCT expression in vivo, our present goal is to identify the physiological signals affecting expression of MCTs in mammalian skeletal muscle. To achieve our goal, we propose experiments to address three specific aims on L6 myocytes incubated in vitro. To simplify the search to identify the putative signals for muscle MCT expression we move from studies on rats and humans in vivo to studies on L6 myocytes in vitro. Based on responsiveness of MCT protein expression, under Aim 1 we will strive to establish a hierarchy of putative physiological signals determining expression of MCT1 and MCT4. The signals we propose to evaluate are: tumor necrosis factor-a (TNF-a), H202, Ca++, adenine nucleotide energy charge (ANEC, by AICAR), pH [H v] and lactate anion [La-]. Preliminary results implicate an NF-KB signaling pathway for MCTI. Current literature implicates a pathway related to T3 in controlling MCT4 expression. Aim 1 studies will involve an assessment of the effects of putative regulators on MCT expression as evaluated by Western blotting. Aim 2 will be to evaluate the hypothesis that muscle MCT expression is subject to pre-translational control. Aim 2 studies will involve comparisons of the levels of muscle MCT protein levels and their respective mRNAs in cultured myocytes subjected to ordered levels of putative physiological signals. If protein and message levels are correlated in response to putative stimuli, then Aim 3 will be to evaluate viability of the hypothesis that MCT expression is regulated at the level of transcription. Aim 3 studies will involve comparisons of the levels of muscle MCT pre-mRNAs, mRNAs and protein levels. We have the tools to achieve the stated aims.

描述(申请人提供)：乳酸在间质和血管中穿梭，是运动中分配碳水化合物势能的主要途径。促进乳酸交换发生在细胞、器官和组织之间，以及通过乳酸、单羧酸转运(MCT)蛋白在细胞间进行。MCT的表达和MCT所占据的细胞结构域存在组织特异性差异。在哺乳动物骨骼肌中，表达两种亚型(MCT1和MCT4)。MCT1存在于肌膜和线粒体中，并与氧化能力有关，而MCT4仅存在于肌膜中，在具有快速肌球蛋白异构体的纤维中含量较高。肌肉MCT1蛋白水平可以受到体内耐力训练和慢性电刺激的影响，而通过培养的L6肌管，我们已经能够影响MCT1蛋白水平。由于在活体内影响MCT表达的生理信号知之甚少，我们目前的目标是确定影响哺乳动物骨骼肌MCT表达的生理信号。为了实现我们的目标，我们提出了针对体外培养的L6肌细胞的三个特定目标的实验。为了简化搜索以确定肌肉MCT表达的可能信号，我们从在体内对大鼠和人的研究转移到对L6肌细胞的体外研究。基于MCT蛋白表达的响应性，在目标1下，我们将努力建立决定MCT1和MCT4表达的可能的生理信号的层次结构。我们建议评估的信号是：肿瘤坏死因子-a(TNF-a)、H202、Ca++、腺核苷酸能荷(ANEC，由AICAR表示)、pH[Hv]和乳酸阴离子[La-]。初步结果提示MCTI存在一条核因子-KB信号通路。目前的文献表明，控制MCT4表达的途径与T3有关。目的1通过Western blotting评价可能的调控因子对MCT表达的影响。目标2将评估肌肉MCT表达受翻译前控制的假设。目的2比较在有序生理信号水平下培养的心肌细胞中肌肉MCT蛋白水平及其各自的mRNAs水平。如果蛋白质和消息水平与假定的刺激反应相关，那么目标3将评估MCT表达在转录水平上受到调控的假设的可行性。目的3研究将包括肌肉MCT前mRNAs、mRNAs和蛋白质水平的比较。我们拥有实现所述目标的工具。