An exercise driven, insulin independent glucose uptake pathway in contracting skeletal muscle

运动驱动、不依赖胰岛素​​的骨骼肌收缩葡萄糖摄取途径

• 批准号: 10614995
• 负责人: Natalie Joyce Norman
• 金额: $ 4.51万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10614995
• 关键词: Active Biological Transport; Affect; Blood Glucose; Bypass; Carbon; Cell membrane; Cell physiology; Cells; Consensus; Contracts; Coupled; Custom; Data; Detection; Development; Diabetes Mellitus; Disease; Elements; Exercise; Family; GLUT 4 protein; Glucose; Glucose Transporter; Goals; Hyperglycemia; Insulin; Insulin Receptor; Insulin Resistance; Insulin deficiency; Ions; K ATPase; Knock-out; Knockout Mice; Knowledge; Label; Link; Mass Spectrum Analysis; Measurement; Measures; Mediating; Membrane; Methods; Modeling; Modification; Mus; Muscle; Outcome; Pathway interactions; Persons; Plasma; Play; Population; Preparation; Protein Isoforms; Research; Role; Sampling; Signal Transduction; Skeletal Muscle; Sodium; Spectrum Analysis; Standardization; Technology; Testing; Transgenic Mice; Transport Process; analytical method; blood glucose regulation; cell type; density; detection limit; diabetes control; glucose transport; glucose uptake; improved; inhibitor; instrument; mRNA Expression; nanomolar; new technology; new therapeutic target; novel; novel therapeutic intervention; protein expression; response; sugar; tool

Diabetes Mellitus (DM) affects more than 10% of the US population and this number is increasing. Skeletal muscles play a major role in glucose homeostasis because of their large capacity to import and store glucose. This makes glucose uptake by skeletal muscle of paramount importance in the development and treatment of DM. Most prior research on glucose uptake in muscle has focused on the insulin-regulated glucose transporter, GLUT4. Quiescent skeletal muscles take up glucose in response to rising plasma insulin, which triggers translocation of GLUT4 from intracellular stores to the plasma membrane. A paradox in the field is that actively contracting muscles take up 50-100 times more glucose than quiescent muscles. However, despite more than 30 years of study, the mechanism by which contracting muscles take up glucose without a requirement for insulin remain incompletely understood. Non-insulin-dependent glucose uptake has been explained in part by signaling mechanisms that bypass the insulin receptor to trigger GLUT4 translocation. However, this model has not accounted for all the glucose taken up by contracting muscle or the glucose uptake that remains in GLUT4 knockout models. Notably, it does not account for the huge discrepancy between GLUT4 translocation (2-fold increase in membrane density) and the up to 100-fold increase in glucose uptake. A consensus is growing that additional mechanisms of muscle glucose uptake exist. Our long-term goal is to uncover previously unrecognized mechanisms of insulin-independent glucose uptake by contracting muscles. This goal is motivated by our recent discovery that a significant component of contraction-stimulated glucose uptake requires Na,K-ATPase (NKA) activity, which we term NKA- dependent glucose uptake. Our central hypothesis is that a component of contraction-stimulated glucose uptake is coupled, either directly or indirectly, to the contraction-stimulated activity of Na,K- ATPase. The relationship between glucose uptake and changes in other ions whose transport is also stimulated by contraction is not known. This knowledge gap persists because the available tools for measuring glucose in cells do not readily accommodate co-measurement of other ions and transported species. The Specific Aims of thisproject are to optimize and standardize a new analytical method, based on Inductively Coupled PlasmaMass Spectroscopy (ICP-MS), to measure simultaneous changes in 13C glucose and Rb+ (a congener for K+), and to use this method to characterize NKA- dependent glucose uptake. At the completion of this study, we will have introduced a new analytical method for 13C detection that can be broadly applied to other cell processes that require multi-species detection, and we will have identified a previously unrecognized mechanism of non-insulin-dependent glucose uptake that may provide new therapeutic targets for treating DM.

糖尿病(DM)影响着超过10%的美国人口，而且这个数字还在增加。 骨骼肌在葡萄糖稳态中起着重要作用，因为它们具有很大的输入能力 并储存葡萄糖。这使得骨骼肌对葡萄糖的摄取在 糖尿病的发展和治疗。以前对肌肉中葡萄糖摄取的大多数研究都集中在 胰岛素调节的葡萄糖转运蛋白，GLUT4。静止的骨骼肌在体内吸收葡萄糖 对血浆胰岛素升高的反应，这会触发GLUT4从细胞内存储转移到 质膜。该领域的一个悖论是，积极收缩的肌肉需要50-100倍的时间 比起静止的肌肉，葡萄糖含量更高。然而，尽管经过了30多年的研究，这种机制 收缩的肌肉在不需要胰岛素的情况下摄取葡萄糖仍然是不完全的 明白了。非胰岛素依赖型葡萄糖摄取的部分原因是信号转导 绕过胰岛素受体触发GLUT4易位的机制。然而，这种模式具有 不包括肌肉收缩所摄取的所有葡萄糖或剩余的葡萄糖摄取 GLUT4淘汰型。值得注意的是，它没有解释GLUT4和GLUT4之间的巨大差异 易位(膜密度增加2倍)和葡萄糖摄取增加高达100倍。 越来越多的人达成共识，认为存在肌肉葡萄糖摄取的其他机制。我们的长期合作 目标是揭示以前未知的胰岛素非依赖性葡萄糖摄取的机制 肌肉收缩。这一目标的动力来自我们最近的发现，即 收缩刺激的葡萄糖摄取需要Na，K-ATPase(NKA)活性，我们称之为NKA- 依赖葡萄糖摄取。我们的中心假设是收缩刺激的一个成分 葡萄糖摄取直接或间接地与Na，K-收缩刺激的活性偶联。 ATPase。葡萄糖摄取与其他离子转运的变化之间的关系 由收缩引起的刺激尚不清楚。这一知识差距之所以持续存在，是因为可用于 在细胞中测量葡萄糖不容易适应其他离子的共同测量和运输 物种。这个项目的具体目标是优化和规范一种新的分析方法， 基于电感耦合等离子体质谱(ICP-MS)的同步检测 ~(13)C葡萄糖和Rb~+(K~+的同系物)的变化，并用这种方法来表征NKA- 依赖葡萄糖摄取。在这项研究完成后，我们将引入一种新的分析 一种可广泛应用于其他需要多物种的细胞过程的13C检测方法 检测，我们将识别出以前未知的非胰岛素依赖的机制 葡萄糖摄取可能为糖尿病的治疗提供新的治疗靶点。