Roles of NAMPT and NAD+ in hypoxic conditioning-induced neurovascular protection in subarachnoid hemorrhage

NAMPT和NAD在蛛网膜下腔出血低氧条件诱导的神经血管保护中的作用

• 批准号: 10660398
• 负责人: GREGORY J ZIPFEL
• 金额: $ 56.49万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-15 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10660398
• 关键词: 3-Dimensional; Address; Anabolism; Aneurysmal Subarachnoid Hemorrhages; Arteries; Automobile Driving; Blood - brain barrier anatomy; Brain; Brain Aneurysms; Brain Injuries; Cerebral Ischemia; Cognitive deficits; Deacetylase; Drug Targeting; Edema; Elements; Endothelial Cells; Enzymes; Experimental Models; Exposure to; Female; Functional disorder; Genetic; Grant; Hypoxia; Individual; Injections; Injury; Knockout Mice; Life; Mediating; Mediator; Methods; Modeling; Molecular; Mus; Neurocognitive Deficit; Neurologic Deficit; Neurons; Niacinamide; Nicotinamide Mononucleotide; Outcome; Pathway interactions; Patients; Perforation; Play; Process; Production; Resistance; Role; Rupture; Ruptured Aneurysm; SIRT1 gene; Secondary to; Stimulus; Stress; Subarachnoid Hemorrhage; Survivors; Testing; Therapeutic; Thrombus; Transgenic Mice; Vasospasm; Wild Type Mouse; Work; aged; blood-brain barrier disruption; cofactor; combat; conditioning; design; improved; inhibitor; knock-down; male; mouse model; neurobehavioral; neurocognitive test; neuroinflammation; neuron loss; neurovascular; new therapeutic target; nicotinamide phosphoribosyltransferase; novel; novel therapeutics; overexpression; pharmacologic; pleiotropism; preconditioning; prevent; protective effect; translational potential; treatment strategy

Project Summary/Abstract Aneurysmal subarachnoid hemorrhage (SAH) is a highly morbid condition, in large part due to secondary brain injury from Early Brain Injury (EBI) and Delayed Cerebral Ischemia (DCI). EBI occurs 1-3 days after ictus and is characterized by blood brain barrier breakdown, neuroinflammation, and neuronal cell death. DCI occurs 4-12 days after ictus and results from a combination of large artery vasospasm and microcirculatory deficits. Given that EBI and DCI are caused by wide-ranging neurovascular deficits, we believe that effective SAH therapy will require a multiplicity of protective effects to maximize the chance of efficacy. We therefore applied a powerful protection strategy with known pleiotropic effects – Conditioning-based therapy – to experimental models of SAH. Conditioning is a concept whereby the brain's inherent resistance to injury can be enhanced by exposure to non-harmful stress stimuli. Previously, we showed that hypoxic conditioning initiated before SAH (Hypoxic Preconditioning) provides robust protection against DCI in an eNOS-dependent manner. Recently, we extended upon these results in three important ways: 1) We showed that hypoxic conditioning initiated 3h after SAH (Hypoxic Post-Conditioning; HPostC) also produces robust neurovascular protection; 2) We showed that the NAD+-dependent deacetylase, Sirtuin 1 (SIRT1), is a key mediator of this protection; and 3) We showed preliminarily that Nicotinamide phosphoribosyltransferase (NAMPT) is likely a key upstream molecule driving the neurovascular protection afforded by HPostC. NAMPT is the rate-limiting enzyme in the NAD+ salvage pathway that converts nicotinamide (NAM) to nicotinamide mononucleotide (NMN) enabling biosynthesis of NAD+, which is an essential co-factor of SIRT1 leading to its activation. In the present grant, we will test our central hypothesis is that NAMPT-driven NAD+ production plays a causal role in the neurovascular protection afforded by HPostC in SAH, and that this protection is either partially or completely SIRT1-mediated. The Specific Aims are (1) Test the hypothesis that NAMPT is necessary for the EBI and DCI protection afforded by HPostC in SAH; (2) Test the hypothesis that therapeutic strategies designed to augment NAMPT activity or increase NAD+ levels mimic the EBI and DCI protection afforded by HPostC in SAH; and if so, determine if this protection is partially or completely SIRT1-mediated; and (3) Determine the translational potential of therapeutic strategies targeting NAMPT and NAD+ by assessing their impact on long- term cognitive deficits after SAH. Methods used include: (a) Two complementary mouse models of SAH; (b) Assessment of NAMPT, NAD+, and SIRT1 levels; (c) Assessment of neuroinflammation, neuronal cell death, vasospasm, microcirculatory deficits, and short- and long-term neurobehavioral deficits; (d) Pharmacologic and genetic inhibition of NAMPT and SIRT1; and (e) Pharmacologic and genetic augmentation of NAMPT or NAD+. Overall, the work proposed in the present grant has the potential to identify an entirely new therapies for the treatment of patients with ruptured brain aneurysms – NAMPT activation or NAD+ augmentation. If successful, these studies will result in an improved understanding of the breadth, mechanism, and sustainability of HPostC- induced neurovascular protection in SAH and determine the translatability of NAMPT- and NAD+-directed therapeutics.

项目概要/摘要 动脉瘤性蛛网膜下腔出血 (SAH) 是一种高度致病的疾病，很大程度上是由于继发性脑损伤所致 早期脑损伤 (EBI) 和迟发性脑缺血 (DCI) 造成的损伤发生在发作后 1-3 天。 其特征是血脑屏障破坏、神经炎症和神经元细胞死亡，发生于 4-12。 发作后几天，是大动脉血管痉挛和微循环缺陷共同作用的结果。 EBI 和 DCI 是由广泛的神经血管缺陷引起的，我们相信有效的 SAH 治疗将 需要多重保护作用才能最大限度地发挥功效，因此我们应用了强大的保护作用。 具有已知多效性效应的保护策略——基于条件的治疗——对实验模型 SAH 是一个概念，通过暴露可以增强大脑对损伤的固有抵抗力。 之前，我们发现低氧调节在SAH（缺氧）之前就开始了。 预处理）以依赖于 eNOS 的方式提供针对 DCI 的强大保护。最近，我们扩展了这一功能。 根据这些结果，我们从三个重要方面进行了研究：1) 我们发现，SAH 后 3 小时开始进行低氧调节 （缺氧后处理；HPostC）也能产生强大的神经血管保护；2）我们表明 NAD+ 依赖性脱乙酰酶 Sirtuin 1 (SIRT1) 是这种保护的关键介质，3) 我们证明； 初步认为烟酰胺磷酸核糖转移酶（NAMPT）可能是驱动该酶的关键上游分子。 HPostC 提供的神经血管保护是 NAD+ 挽救途径中的限速酶。 将烟酰胺 (NAM) 转化为烟酰胺单核苷酸 (NMN)，从而实现 NAD+ 的生物合成， 是导致 SIRT1 激活的重要辅助因子。 在目前的资助中，我们将测试我们的中心假设，即 NAMPT 驱动的 NAD+ 产生起着因果作用 HPostC 在 SAH 中提供的神经血管保护中的作用，并且这种保护是部分或 完全由 SIRT1 介导。 具体目标是 (1) 检验 NAMPT 对于 NAMPT 是必要的假设。 HPostC 在 SAH 中提供的 EBI 和 DCI 保护（2）检验治疗策略设计的假设； 增强 NAMPT 活性或增加 NAD+ 水平，模仿 HPostC 提供的 EBI 和 DCI 保护 SAH；如果是，确定这种保护是否部分或完全由 SIRT1 介导；以及 (3) 确定 通过评估针对 NAMPT 和 NAD+ 的治疗策略对长期治疗的影响，研究其转化潜力。 SAH 后的术语认知缺陷使用的方法包括： (a) 两种互补的 SAH 小鼠模型； NAMPT、NAD+和SIRT1水平的评估；(c)神经炎症、神经元细胞死亡的评估； (d) 药理学和 NAMPT 和 SIRT1 的遗传抑制；以及 (e) NAMPT 或 NAD+ 的药理学和遗传增强。 总体而言，本次资助中提出的工作有可能为该病确定一种全新的疗法 脑动脉瘤破裂患者的治疗 – NAMPT 激活或 NAD+ 增强 如果成功， 这些研究将加深对 HPostC 的广度、机制和可持续性的理解。 诱导 SAH 中的神经血管保护并确定 NAMPT 和 NAD+ 导向的可翻译性 疗法。