PE methylation in skeletal muscle energy efficiency

项目总结/摘要 在过去的二十年里，肥胖相关的代谢性疾病的流行以惊人的速度增加。 生活方式的改变促进了长期体重管理的有限成功，而许多医学研究表明， 干预有副作用。降低能源效率可能提供一种替代办法， 促进减肥。由于骨骼肌是一个具有大质量和代谢需求的器官， 预计骨骼肌中无效率将促进全身能量的显著增加 支出对膜囊泡的研究表明，肌浆网/内质网的能量效率 (SR/ER）Ca 2 +-ATP酶（SERCA）泵可通过SR磷脂的组成来调节。在这 应用，我们建议研究磷脂酰乙醇胺（PE）甲基化在调节 肌肉能量效率。PE甲基化由酶PE甲基转移酶（PEMT）催化，并且小鼠 具有PEMT的全身缺失的人被保护免于饮食诱导的肥胖。我们发现， 来自PEMT敲除小鼠的肌肉具有升高的代谢率，这可能是由于 SERCA能效。我们假设PE甲基化缺陷降低SERCA能量效率 通过其对骨骼肌SR磷脂组成的影响。目的1：通过组织特异性灭活 PEMT，我们将确定PE甲基化缺陷如何影响细胞Ca 2+处理，以增加骨骼肌的 肌肉能量消耗目标2：在多个实验模型中，我们将确定是否改变 肌肉SR磷脂将足以诱导静息代谢率的变化， 饮食引起的肥胖目的3：推导出PE收缩肌肉的机械效率（η） 甲基化缺陷我们还将研究PEMT的失活是否会增加抗肥胖作用。 定期锻炼的效果。

Project Summary/Abstract A pandemic in obesity-related metabolic diseases has increased at an alarming rate over the last two decades. Lifestyle changes promote limited success for long-term weight management, while many medical interventions have side effects. Reduction in energy efficiency might provide an alternative approach to promote weight loss. As skeletal muscle is an organ with large mass and metabolic demand, energy inefficiency in skeletal muscle would be predicted to promote substantial increase in whole body energy expenditure. Studies in membrane vesicles suggest that energy efficiency of sarco/endoplasmic reticulum (SR/ER) Ca2+-ATPase (SERCA) pump may be modulated by composition of SR phospholipids. In this application, we propose to investigate the role of phosphatidylethanolamine (PE) methylation in regulating muscle energy efficiency. PE methylation is catalyzed by an enzyme PE methyltransferase (PEMT), and mice with whole body deletion of PEMT are protected from diet-induced obesity. We discovered that skeletal muscles from PEMT knockout mice have elevated metabolic rate, which was likely promoted by a reduction in SERCA energy efficiency. We hypothesize that PE methylation deficiency reduces SERCA energy efficiency through its effects on skeletal muscle SR phospholipid composition. Aim 1: With tissue-specific inactivation of PEMT, we will determine how PE methylation deficiency affects cellular Ca2+ handling to increase skeletal muscle energy expenditure. Aim 2: In multiple experimental models, we will determine whether alterations in muscle SR phospholipids would be sufficient to induce changes in resting metabolic rate and propensity for diet-induced obesity. Aim 3: We will derive mechanical efficiency (η) of contracting muscles with PE methylation deficiency. We will also examine whether inactivation of PEMT would augment the anti-obesogenic effect of regular exercise.