Alterations in membrane composition and function eith calorie restriction

描述（由申请人提供）：在没有营养不良的情况下，热量限制（CR）是唯一一种在实验室啮齿类动物中一直被证明可以延长最长寿命并预防或延迟与年龄相关的病理生理变化发生的干预措施。有人提出，膜脂肪酸不饱和程度是促进长寿的一个主要因素，膜不饱和程度的降低可能是CR延缓衰老的机制。然而，仅通过调节膜脂过氧化物性将膜与衰老联系起来的理论可能过于笼统，因为它们忽略了脂质改变对膜相关过程的影响。如活性氧（ROS）的产生和电子传递链的活性。此外，这些理论忽略了膜蛋白在防止氧化损伤中的作用。考虑到膜在调节氧化应激中的核心作用，我们假设CR引起血浆和线粒体的改变！导致新的生物能量平衡，从而减少ROS的产生和膜氧化损伤。我们提出三个具体目标来检验这一理论：具体目标1；测定对照组和40% CR C57BL/6小鼠肝脏和骨骼肌线粒体膜和质膜的膜组成（脂肪酸、磷脂和辅酶Q）。将完成全面的脂质分析，以量化所有类别的磷脂及其组成脂肪酸。膜氧化损伤的标志物也将被测量。这些研究将彻底量化cr诱导的膜脂组成的变化，并确定这些变化是否导致膜过氧化物性降低。具体目标2；确定CR是否诱导对照小鼠和40% CR C57BL/6小鼠肝脏和骨骼肌线粒体和质膜相关过程的改变。与能量消耗、活性氧产生、氧化损伤和抗氧化防御相关的膜相关过程将被测量。各组CR小鼠还将被喂食脂肪来源为牛油（高饱和）、大豆油（高亚油酸）或鲱鱼油（高n-3多不饱和脂肪酸）的饲料，以确定CR诱导的线粒体和质膜功能的变化是否需要改变膜脂肪酸组成。具体目标3：确定膜长链多不饱和脂肪酸的减少或质膜氧化还原系统活性的增加是否需要CR延长寿命。将使用遗传（脂肪-1小鼠）和饮食干预来确定CR诱导的n-3脂肪酸、亚油酸或膜饱和度的变化是否需要延长寿命。此外，NAD(P) h -醌还原酶敲除（NQO1 KO）小鼠将被用来确定是否需要刺激PM氧化还原系统来延长CR的寿命。

DESCRIPTION (provided by applicant): Calorie restriction (CR), without malnutrition, is the only intervention that has consistently been shown to increase maximum life span and prevent or delay the onset of age-associated pathophysiological changes in laboratory rodents. It has been proposed that the degree of membrane fatty acid unsaturation is a major factor contributing to longevity, and that a decrease in membrane unsaturation may be the mechanism for the retardation of aging with CR. Such theories that link membranes to aging solely through modulation of membrane lipid peroxidizability, however, may be too general since they overlook the affect lipid alterations will also have on membrane-linked processes, such as reactive oxygen species (ROS) production and electron transport chain activity. Also, these theories ignore the role membrane proteins play in protecting against oxidative damage. Considering the central role that membranes play in regulating oxidative stress, we hypothesize that CR causes an alteration in plasma and mitochondria! membrane composition that results in a new bioenergetic balance leading to decreases in both ROS production and membrane oxidative damage. We propose three specific aims to test this theory: Specific Aim 1; To determine membrane composition (fatty acids, phospholipids and coenzyme Q) of mitochondrial and plasma membranes from liver and skeletal muscle of control and 40% CR C57BL/6 mice. Comprehensive lipid analysis will be completed to quantify all classes of phospholipids and their constituent fatty acids. Markers of membrane oxidative damage will also be measured. These studies will thoroughly quantify CR-induced changes in membrane lipid composition, and determine if these changes result in a decrease in membrane peroxidizability. Specific Aim 2; To determine if CR induces alterations in mitochondrial and plasma membrane-linked processes in liver and skeletal muscle from control and 40% CR C57BL/6 mice. Membrane-linked processes related to energy expenditure, ROS production, oxidative damage, and antioxidant defenses will be measured. Groups of CR mice will also be fed diets where the fat source is beef tallow (highly saturated), soybean oil (high linoleic acid), or menhaden fish oil (high n-3 polyunsaturated fatty acids) to determine if alterations in membrane fatty acid composition are required for CR-induced changes in mitochondrial and plasma membrane functions. Specific Aim 3: To determine if decreases in membrane long chain polyunsaturated fatty acids or increases in activity of the plasma membrane redox system are required for life span extension with CR. Genetic (fat-1 mice) and dietary interventions will be used to determine if CR-induced changes in n-3 fatty acids, linoleic acid, or membrane saturation are required for life span extension. Also, NAD(P)H-quinone reductase knockout (NQO1 KO) mice will be used to determine if stimulation of the PM redox system is required for life span extension with CR.