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.

项目摘要/摘要 动脉瘤性蛛网膜下腔出血（SAH）是一种高病态的状况，在很大程度上是由于继发性大脑 早期脑损伤（EBI）和脑缺血延迟（DCI）受伤。 EBI发生在ICTUS之后1-3天，是 以血脑屏障的分解，神经炎症和神经元细胞死亡为特征。 DCI发生4-12 ICT后几天，大动脉血管痉挛和微循环缺陷的组合。给出 EBI和DCI是由大范围神经血管缺陷引起的，我们认为有效的SAH疗法将 需要多种保护效应以最大程度地提高效率的机会。因此，我们应用了一个强大的 具有已知多效效应的保护策略 - 基于条件的治疗 - SAH。调理是一个概念，可以通过暴露来增强大脑对伤害的抗性抗性 进行无害的压力刺激。以前，我们表明在SAH之前启动的低氧条件（低氧） 预处理）以依赖eNOS的方式为DCI提供了强大的保护。最近，我们扩展了 根据这些结果，以三种重要的方式：1）我们表明，SAH后3H启动了低氧条件 （缺氧后条件； HPOSTC）还会产生强大的神经血管保护； 2）我们证明了 NAD+依赖性脱乙酰基酶Sirtuin 1（SIRT1）是该保护的关键介体。 3）我们展示了 首先认为烟酰胺磷酸蛋白酶基转移酶（NAMPT）可能是驱动驱动的钥匙上游分子 HPOSTC提供的神经血管保护。 NAMPT是NAD+打捞途径中的限速酶 这将烟酰胺（NAM）转换为烟酰胺单核苷酸（NMN），使NAD+的生物合成 是SIRT1的必不可少的共同因素，导致其激活。 在目前的赠款中，我们将测试我们的中心假设是NAMPT驱动的NAD+生产有因果关系 HPOSTC在SAH中提供的神经血管保护中的作用，并且该保护是部分或 完全介导。具体目的是（1）检验以下假设：NAMPT对于 HPOSTC在SAH中提供的EBI和DCI保护； （2）检验设计策略设计的假设 增加NAMPT活动或增加NAD+水平模仿HPOSTC提供的EBI和DCI保护 sah;如果是这样，请确定该保护是部分还是完全介导； （3）确定 通过评估其对长期的影响，针对NAMPT和NAD+的理论策略的转化潜力 术语认知定义在SAH之后。所使用的方法包括：（a）两种完整的鼠标SAH模型； （b） 评估NAMPT，NAD+和SIRT1水平； （c）评估神经炎症，神经元细胞死亡， 血管痉挛，微循环缺陷以及短期和长期神经行为缺陷； （d）药理学和 NAMPT和SIRT1的遗传抑制； （e）NAMPT或NAD+的药理和遗传增强。 总体而言，本赠款中提出的工作有可能确定针对 治疗脑部动脉瘤破裂的患者 - NAMPT激活或NAD+增强。如果成功， 这些研究将提高人们对HPSTC-的广度，机制和可持续性的了解。 SAH诱导神经血管保护，并确定NANP-和NAD+指导的转换性 疗法。