Elucidating the Role of Endothelial NAD Metabolism in Atherosclerosis

阐明内皮 NAD 代谢在动脉粥样硬化中的作用

• 批准号: 10563112
• 负责人: Ioana Soaita
• 金额: $ 4.68万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10563112
• 关键词: Adenine Nucleotides; Adhesions; Age; Aging; Aorta; Area; Arterial Fatty Streak; Atherosclerosis; Blood Vessels; Bypass; Carbon Isotopes; Cardiovascular system; Cause of Death; Cells; Clinical; Consumption; Coupled; Deacetylase; Deacetylation; Development; Endothelial Cells; Endothelium; Enzymes; Equilibrium; Event; Family; Functional disorder; Histology; Homeostasis; Human; Hyperlipidemia; Impairment; Inflammation; Intervention; Label; Lead; Lipids; Liver; Mediating; Metabolic; Metabolism; Methods; Modeling; Mus; NOS3 gene; Niacinamide; Nicotinamide adenine dinucleotide; Nitric Oxide; Oils; Oral; Oral Administration; Oxidative Stress; Pathogenesis; Pathologic; Pathology; Pathway interactions; Phenotype; Prevalence; Process; Production; Public Health; Reaction; Reporting; Risk Factors; Role; SIRT1 gene; Sirtuins; Stains; Supplementation; Testing; Text; Therapeutic; Tissues; United States; Vasodilation; Work; aged; atherogenesis; atherosclerosis risk; career; experimental study; gain of function; human disease; improved; in vitro activity; loss of function; metabolic abnormality assessment; modifiable risk; mouse model; nicotinamide phosphoribosyltransferase; nicotinamide-beta-riboside; novel therapeutic intervention; overexpression; prevent; stable isotope

Project Summary Atherosclerosis remains a leading cause of death in the United States, even in the context of aggressive clinical and public health efforts to lower risk factors such as hyperlipidemia. Thus, there is a significant need for better mechanistic understanding of atherosclerosis pathogenesis in order to develop novel therapeutic strategies downstream of circulating risk factors. Atherosclerosis pathogenesis begins in the endothelial layer of the arterial wall: endothelial cell dysfunction (ECD) and EC inflammation precede atherosclerotic plaque formation and are associated with adverse cardiovascular events. Both ECD and EC inflammation increase with age, and age is a major non-modifiable risk factor for atherosclerosis. Importantly, activation of sirtuin (SIRT) family of nicotinamide adenine dinucleotide (NAD+) - dependent deacetylases, particularly SIRT1, has been reported to slow a variety of age-associated phenotypes. In particular, our lab and others have shown that levels of endothelial NAD+ decrease with age, and that endothelial-specific overexpression of SIRT1 is sufficient to slow ECD and progression of atherosclerosis. Furthermore, oral administration of NAD+ precursors in aged mice increases aortic SIRT1 expression and activity, and reduces ECD, suggesting that increasing NAD+ availability can promote SIRT1 activity in aged ECs. Loss of NAD+ balance thus appears to be central to atherogenesis, but little is known about how ECs maintain NAD homeostasis. Quantitative flux analysis of NAD+ precursors in live mice has recently uncovered that liver-derived nicotinamide (NAM) is the main circulating NAD+ precursor that reaches tissues. This suggests that the enzyme NAM phosphoribosyltransferase (NAMPT), which catalyzes the first and rate-limiting step in NAD+ synthesis from NAM, is critical for producing endothelial NAD+ and maintaining the activity of NAD+ - dependent enzymes. Thus, I hypothesize that endothelial NAMPT is cell-autonomously required to produce NAD+ and maintain endothelial SIRT1 activity, and that endothelial NAMPT overexpression will protect against progression of atherosclerosis. To test this hypothesis, we have generated endothelial-specific gain-of-function (GOF) and loss-of-function (LOF) NAMPT mouse models. In Aim 1, I will use cultured primary arterial ECs and stable isotope carbon tracing coupled with quantitative flux analysis to calculate rates of NAMPT NAD+ production and SIRT1 NAD+ consumption. I will also determine if NAMPT activity is required for SIRT1 deacetylation activity, and if NAMPT activation is sufficient to maintain SIRT1 activity upon oxidative stress. In Aim 2, I will test if NAMPT GOF or oral NAD+ supplementation is sufficient to slow progression of atherosclerosis, and if NAMPT LOF accelerates atherosclerosis. Ultimately, this work will improve understanding of EC NAD+ metabolism and its role in maintaining SIRT1 activity, and inform if NAMPT activation and/or NAD+ replenishment could be a therapeutic avenue for reducing the burden of atherosclerosis independently of circulating risk factors such as hyperlipidemia.

项目摘要 动脉粥样硬化仍然是美国的主要死亡原因，即使在积极的临床背景下也是如此 以及降低高脂血症等风险因素的公共卫生努力。因此，很有必要更好地 从机制上理解动脉粥样硬化的发病机制，以开发新的治疗策略 下游的循环风险因素。动脉粥样硬化的发病机制始于动脉内皮层。 壁：内皮细胞功能障碍(ECD)和EC炎症是动脉粥样硬化斑块形成的先兆 与不良心血管事件有关。ECD和EC炎症均随年龄增长而增加，而年龄是 动脉粥样硬化的主要不可改变的危险因素。重要的是，烟酰胺sirtuin(SIRT)家族的激活 据报道，依赖于腺二核苷酸(NAD+)的脱乙酰酶，特别是SIRT1，可以减缓一系列 与年龄相关的表型。特别是，我们的实验室和其他实验室已经表明，内皮细胞NAD+的水平 随着年龄的增长而减少，内皮特异性SIRT1的过度表达足以减缓ECD和 动脉粥样硬化的进展。此外，老年小鼠口服NAD+前体的次数增加 主动脉SIRT1的表达和活性，并减少ECD，这表明增加NAD+的可用性可以促进 老年内皮细胞SIRT1活性的研究因此，NAD+平衡的丧失似乎是动脉粥样硬化形成的中心，但我们知之甚少 关于ECs如何维持NAD动态平衡。活体小鼠体内NAD+前体细胞的定量流量分析 最近发现，肝源性烟酰胺(NAM)是循环中主要的NAD+前体， 纸巾。这表明NAM磷酸核糖基转移酶(NAMPT)催化第一和 从NAM合成NAD+的限速步骤，对于产生内皮细胞NAD+和维持 依赖NAD+的酶的活性。因此，我假设内皮NAMPT是细胞自主的 产生NAD+和维持内皮细胞SIRT1活性所需的，内皮细胞NAMPT 过度表达将防止动脉粥样硬化的进展。为了检验这一假设，我们有 建立了内皮特异性功能增强(GOF)和功能丧失(LOF)NAMPT小鼠模型。在AIM 1、我将使用培养的原代动脉内皮细胞和稳定同位素碳示踪结合定量流量分析 计算NAMPT NAD+生产和SIRT1 NAD+消耗率。我还会确定NAMPT是否 SIRT1去乙酰化活性需要活性，如果NAMPT激活足以维持SIRT1活性 对氧化应激的影响。在目标2中，我将测试NAMPT GOF或口服NAD+补充剂是否足以减缓速度 动脉粥样硬化的进展，如果NAMPT LOF加速动脉粥样硬化。最终，这项工作将得到改进 了解EC NAD+代谢及其在维持SIRT1活性中的作用，并告知NAMPT是否激活 和/或NAD+补充可能是减轻动脉粥样硬化负担的治疗途径 不受高脂血症等循环危险因素的影响。