A novel therapeutic approach for Alzheimer Disease (AD)

项目摘要 阿尔茨海默病(AD)是一种引起细胞和机体代谢的慢性神经系统疾病 功能障碍、渐进性记忆衰退和认知障碍。烟酰胺腺嘌呤二核苷酸(NAD+) 是一种重要的代谢物，涉及细胞生物能量学、基因组稳定性、线粒体动态平衡、 适应性应激反应和细胞存活。越来越多的证据表明，NAD+的下降 伴随着AD的进展。在哺乳动物细胞中，NAD+生物合成的挽救途径是 NAD+生物合成的主要途径，其中烟酰胺磷酸核糖基转移酶(NAMPT)是... 限制酶。因此，系统地维持较高的NAD+水平的生理手段，以增强细胞 大脑中的代谢活动可能代表着一种有效的抗AD干预。红细胞(RBC)， 造血干/祖细胞在骨髓中的分化并释放到血液中 循环系统成熟后，是全身最丰富的细胞类型，因此，NAD+增加 利用遗传干预在这些细胞中合成可能提供一种生理手段来系统和 NAD+通过循环系统在全身持续升高。在这里，我们开发了一种创新的 方法，即使用血清型助手依赖腺病毒(HD-Ad5)在红细胞中过表达NAMPT 在小鼠模型中进行自体HSPC的体内转导。我们假设NAMPT 红细胞过度表达(OE)提供系统和持续的NAD+产生，以增加代谢活性， 对抗AD患者NAD+下降，改善AD病情。为了检验我们的假设，我们提出了 遵循两个具体目标。目标1将测试RBC中的NAMPT OE可以系统地提高NAD+水平 新陈代谢活跃的器官，并在细胞和机体水平上增强代谢活动。我们将转译为 含NAMPT基因的HD-Ad5-NAMPT载体诱导HSPC在红细胞中过表达NAMPT 长期检测大脑和整个动物体内的NAD+水平和新陈代谢。AIM 2将测试 RBC中的NAMPT OE能对抗APP/PS1 AD小鼠模型NAD+的下降，减轻AD的病理改变。 用不同的方法，我们将确定NAMPT OE在红细胞中对神经元变性、淀粉样蛋白的影响 AD小鼠模型中β(Aβ)负荷、成年神经发生、认知功能减退和痴呆。此应用程序是 在概念、假设和方法上具有很强的创新性。利用遗传方法靶向红细胞进行治疗 在这里，AD而不是血液系统的遗传性疾病可能会改变基因治疗范式，并代表 一种新的治疗策略。根据我们的初步数据，我们的项目是高度可行的，因此，既有科学的 以及对阿尔茨海默病和其他大脑疾病的翻译意义。

Project Summary Alzheimer's Disease (AD) is a chronic neurological disorder causing cellular and organismal metabolic dysfunction, progressive memory decline and cognitive impairments. Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite that is involved in cellular bioenergetics, genomic stability, mitochondrial homeostasis, adaptive stress responses, and cell survival. A growing body of evidence indicates that NAD+ decline is accompanied with progression of AD. In mammalian cells, the salvage pathway of NAD+ biosynthesis is the predominant pathway for NAD+ biosynthesis, where nicotinamide phosphoribosyltransferase (Nampt) is the rate- limiting enzyme. Thus, physiological means to systematically maintain elevated NAD+ levels to augment cellular metabolic activity in the brain may represent an efficient anti-AD intervention. Red blood cells (RBCs), differentiated from hematopoietic stem/progenitor cells (HSPCs) in bone marrow (BM) and release to blood circulation system after maturation, are the most abundant cell type in whole body, and thus, increase in NAD+ synthesis in these cells using genetic interventions may provide a physiological means for systematic and sustained elevation of NAD+ in whole body through the circulation system. Here we developed an innovative approach, i.e., using serotype helper-dependent adenovirus (HD-Ad5) to overexpress NAMPT in the RBCs following in vivo transduction of autologous HSPCs in mouse model. We hypothesize that Nampt overexpression (OE) in RBCs provides systematic and sustained NAD+ production to increase metabolic activity, and counteract NAD+ decline in AD and ameliorate AD conditions. To test our hypothesis, we propose the following two specific aims. Aim 1 will test that Nampt OE in RBCs can systematically elevates NAD+ levels in metabolically active organs and enhances metabolic activity at cellular and organismal levels. We will transduce HSPCs by HD-Ad5-Nampt vectors containing Nampt gene to overexpress Nampt in RBCs and subsequently examine the NAD+ levels and metabolism in the brain and whole animal over a long-term period. Aim 2 will test that Nampt OE in RBCs can counteract NAD+ decline and alleviate AD pathologies in APP/PS1 AD mouse model. Using different methods, we will determine the effect of Nampt OE in RBCs on neuronal degeneration, Amyloid β (Aβ) burden, adult neurogenesis, cognitive decline, and dementia in AD mouse model. This application is highly innovative in concept, hypothesis and approach. Targeting RBCs using genetic approach for the therapy of genetic diseases here AD other than in the blood system may change gene therapy paradigm and represents a novel therapeutic strategy. Our project is highly feasible based on our preliminary data, thus, has both scientific and translational significances for AD and other brain diseases.