Isoform-specific roles of the Na,K-ATPase in skeletal muscle

Na,K-ATP 酶在骨骼肌中的异构体特异性作用

基本信息

批准号：
9210667
负责人：
JUDITH A HEINY
金额：
$ 1.54万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-09-01 至 2016-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9210667
关键词：
Action Potentials Acute Adrenergic Agonists Adrenergic Receptor Adult Animal Model Animals Biochemical Biological Assay Cachexia Chronic Obstructive Airway Disease Collaborations Contracts Coronary artery Data Disease Enzymes Event Exercise Fatigue Gene Targeting Genes Genetic Genetic Models Health Heart failure Home environment Housekeeping Image Impairment In Vitro Lead Ligation Measurement Measures Membrane Potentials Molecular Molecular Target Mus Muscle Muscle Contraction Muscle Fatigue Muscle Weakness Muscle function Muscular Dystrophies Na(+)-K(+)-Exchanging ATPase Outcome Study Performance Phosphorylation Physiological Play Positioning Attribute Property Protein Isoforms Public Health Receptor Activation Regulation Research Resistance Resources Rest Role Skeletal Muscle Testing Therapeutic Intervention Tissues Universities Up-Regulation Work beta-2 Adrenergic Receptors enzyme activity exercise intolerance extracellular genetic manipulation in vivo meetings membrane excitation molecular targeted therapies mouse model novel phospholemman resistance mechanism sarcopenia therapeutic target

项目摘要

DESCRIPTION (provided by applicant): Skeletal muscle weakness and fatigue is a common, debilitating condition in heart failure, sarcopenia, cachexia, muscular dystrophies, COPD, and other disorders. Na,K-ATPase activity is dramatically stimulated during muscle contraction and is absolutely required to maintain force and exercise performance. However, few studies have examined the role the Na,K-ATPase isoforms in muscle weakness and fatigue. Adult skeletal muscles express mainly the α2 isoform of the Na,K-ATPase, in contrast to most other tissues which express mainly the α1 isoform. The role of the α2 isoform in skeletal muscle and the mechanisms by which its activity is stimulated are not known. The central hypotheses of this research is that the Na,K-ATPase α2 isoform provides a reserve capacity which is largely inactive at rest but is rapidly stimulated during contraction, to meet the increased demand for Na/K transport; and that its regulation is achieved in part by phosphorylation of the muscle-specific FXYD1 subunit of the Na,K-ATPase. This hypothesis will be tested using a novel gene targeted mouse which specifically lacks the Na,K-ATPase α2 in adult skeletal muscles (skα2-/-) and shows marked exercise intolerance and skeletal muscle weakness. The Specific Aims are to: 1) Determine the acute role of the Na,K-ATPase α2 enzyme in maintaining force and exercise performance; 2) Determine the role of the Na,K-ATPase α2 enzyme in membrane excitation in the transverse tubules and resistance to fatigue; and 3) a, Define the role of FXYD1 phosphorylation in the acute stimulation of Na,K-ATPase α2 activity by α2- adrenergic receptor activation during contraction; b, Determine the contribution of altered Na,K-ATPase content or function to muscle fatigue and exercise intolerance in heart failure. These Aims will be approached using an integrated strategy which combines genetic manipulations in the mouse with functional measurements from the animal to the cellular and subcellular level. Collectively, this project will advance our understanding of the physiological roles of the Na,K-ATPase α2 isoform and the mechanisms by which it is regulated in skeletal muscle, and identify new molecular targets for therapeutic interventions in muscle weakness and fatigue.

描述（由适用提供）：骨骼肌无力和疲劳是心力衰竭，肌肉减少症，卡氏症，肌肉发育不良，COPD和其他疾病的常见状况。 Na，K-ATPase活性在肌肉收缩期间受到巨大刺激，并且绝对需要保持力和运动表现。但是，很少有研究检查Na，K-ATPase同工型在肌肉无力和疲劳中的作用。成年骨骼肌主要表达Na，K-ATPase的α2同工型，与主要表达α1同工型的大多数其他组织相反。尚不清楚α2同工型在骨骼肌中的作用和刺激其活性的机制。这项研究的中心假设是Na，K-ATPaseα2同工型提供了储备能力，在静止状态下在很大程度上不活动，但在收缩期间迅速刺激，以满足对Na/k运输的需求增加；并且它的调节部分是通过Na，K-ATPase的肌肉特异性FXYD1亚基的磷酸化来实现的。该假设将使用具有新颖的基因靶向小鼠进行检验，该小鼠在成年骨骼肌（SKα2 - / - ）中特异性缺乏Na，K-ATPaseα2，并显示出明显的运动性运动和骨骼肌无力。具体目的是：1）确定Na，K-ATPaseα2酶在维持力和运动性能中的急性作用； 2）确定Na，K-ATPaseα2酶在横向管中膜兴奋中的作用以及对疲劳的抗性； 3）a，定义FXYD1磷酸化在收缩过程中通过α2-肾上腺素能受体激活对Na，K-ATPaseα2活性的急性刺激的作用； b，确定改变Na，K-ATPase含量或功能对肌肉疲劳和心力衰竭运动的贡献。将使用综合策略来实现这些目标，该策略将小鼠中的遗传操作与从动物到细胞和亚细胞水平的功能测量相结合。总的来说，该项目将提高我们对Na，K-ATPaseα2同工型的物理作用以及在骨骼肌中调节其的机制的理解，并确定新的分子靶标在肌肉无力和疲劳中治疗干预措施。