Alterations in membrane composition and function eith calorie restriction

描述（由申请人提供）：热量限制（CR），无营养不良，是唯一一种一直被证明可延长实验室啮齿动物最长寿命并预防或延迟年龄相关病理生理学变化发生的干预措施。有人提出，膜脂肪酸不饱和度是一个主要因素，有助于长寿，膜不饱和度的降低可能是与CR延缓老化的机制。然而，这种仅通过调节膜脂质过氧化能力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，例如活性氧（ROS）的产生和电子传递链活性。此外，这些理论忽略了膜蛋白在保护免受氧化损伤中的作用。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！膜组成导致新的生物能量平衡，从而减少活性氧的产生和膜氧化损伤。我们提出了三个具体的目标来测试这一理论：具体目标1：确定膜组成（脂肪酸，磷脂和辅酶Q）的线粒体和质膜从对照组和40%CR C57 BL/6小鼠的肝脏和骨骼肌。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。还将测量膜氧化损伤的标志物。这些研究将彻底量化CR诱导的膜脂质组成的变化，并确定这些变化是否会导致膜过氧化能力的降低。具体目标2;确定CR是否诱导对照组和40%CR C57 BL/6小鼠肝脏和骨骼肌中线粒体和质膜连接过程的改变。将测量与能量消耗、ROS产生、氧化损伤和抗氧化防御相关的膜相关过程。还将对CR小鼠组饲喂脂肪来源为牛脂（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变化是否需要膜脂肪酸组成的改变。具体目标3：确定CR延长寿命是否需要减少膜长链多不饱和脂肪酸或增加质膜氧化还原系统活性。遗传（fat-1小鼠）和饮食干预将用于确定CR诱导的n-3脂肪酸、亚油酸或膜饱和度变化是否是延长寿命所需的。此外，NAD（P）H-醌还原酶敲除（NQO 1 KO）小鼠将用于确定CR延长寿命是否需要刺激PM氧化还原系统。

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.