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

• 批准号: 8579574
• 负责人: JUDITH A HEINY
• 金额: $ 42.94万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-09-01 至 2018-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8579574
• 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; enzyme activity; extracellular; genetic manipulation; in vivo; meetings; membrane excitation; mouse model; novel; phospholemman; public health relevance; resistance mechanism; sarcopenia; therapeutic target

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 ?2 isoform of the Na,K-ATPase, in contrast to most other tissues which express mainly the ?1 isoform. The role of the ?2 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 ?2 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 ?2 in adult skeletal muscles (sk??2-/-) and shows marked exercise intolerance and skeletal muscle weakness. The Specific Aims are to: 1) Determine the acute role of the Na,K-ATPase ?2 enzyme in maintaining force and exercise performance; 2) Determine the role of the Na,K-ATPase ?2 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 ?2 activity by ?2- 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 ?2 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（由申请人提供）：骨骼肌无力和疲劳是心力衰竭、肌肉减少症、恶病质、肌营养不良、慢性阻塞性肺病和其他疾病中常见的使人衰弱的病症。 Na,K-ATP酶活性在肌肉收缩过程中受到显着刺激，并且是维持力量和运动表现所必需的。然而，很少有研究探讨 Na,K-ATP 酶亚型在肌肉无力和疲劳中的作用。成人骨骼肌主要表达 Na,K-ATP 酶的 α2 同工型，而大多数其他组织主要表达 α1 同工型。 α2亚型在骨骼肌中的作用以及刺激其活性的机制尚不清楚。这项研究的中心假设是，Na,K-ATPase ?2 同工型提供了一种储备能力，该能力在静止时基本上不活跃，但在收缩期间迅速受到刺激，以满足 Na/K 运输增加的需求；并且其调节部分是通过 Na,K-ATP 酶的肌肉特异性 FXYD1 亚基的磷酸化来实现的。该假设将使用一种新型基因靶向小鼠进行测试，该小鼠在成年骨骼肌中特别缺乏 Na,K-ATPase α2 (sk??2-/-)，并表现出明显的运动不耐受和骨骼肌无力。具体目标是： 1) 确定 Na,K-ATPase ?2 酶在维持力量和运动表现方面的急性作用； 2) 确定Na,K-ATPase α2酶在横小管膜兴奋和抗疲劳中的作用； 3) a，定义 FXYD1 磷酸化在收缩过程中通过 β2- 肾上腺素能受体激活急性刺激 Na,K-ATPase β2 活性中的作用； b，确定 Na,K-ATP 酶含量或功能改变对心力衰竭中肌肉疲劳和运动不耐受的影响。这些目标将通过综合策略来实现，该策略将小鼠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，该项目将增进我们对 Na,K-ATPase ?2 同工型的生理作用及其在骨骼肌中调节机制的理解，并确定肌肉无力和疲劳治疗干预的新分子靶点。