Senescence, NAD+ decrease and Alzheimer's disease and related dementias Alzheimer's disease and related dementias

项目摘要 衰老和阿尔茨海默病（AD）及相关痴呆伴随着全身和全身神经系统的显著变化， 细胞代谢最近发表的几项结果支持了NAD代谢的变化起作用的模型。 在AD中的作用以及通过NAD增强剂恢复NAD水平防止疾病进展。的 酶CD 38消耗NAD，在衰老过程中增加，缺乏CD 38的小鼠免受年龄相关的损伤。 NAD下降。在双转基因小鼠模型中疾病进展期间脑中CD 38水平增加 AD（APP和早老素-1）。值得注意的是，在APP.PS AD小鼠模型中删除CD 38减少了淀粉样蛋白， 与野生型小鼠相比，减少斑块和改善空间学习。我们自己的新观察表明， 来自衰老细胞的上清液（SASP）激活巨噬细胞中的CD 38表达。这些发现表明 衰老、SASP和与衰老相关的认知功能下降之间的直接因果关系 在AD期间通过NAD水平的变化。我们的工作假设是大脑中的衰老细胞诱导NAD 通过衰老相关分泌表型（SASP）诱导CD 38表达而降低。我们 建议： 目标1.为了确定AD小鼠模型中神经元、星形胶质细胞和小胶质细胞的NAD代谢组， 在衰老细胞培养物和AD患者组织样品中。使用流式细胞术，单细胞转录组学 (with核心D）、蛋白质组学/代谢组学分析（使用核心C）和MHC/IF免疫染色，我们将测量 NAD水平和调节神经元中NAD代谢的代谢酶的蛋白质表达水平， 在培养物中以及在AD和AD患者的小鼠模型中诱导衰老后的星形胶质细胞和小胶质细胞 脑组织 目的2：确定细胞衰老和SASP对NAD代谢、增殖， 使用共培养的小胶质细胞、星形胶质细胞和神经元。对于核心B和项目1和项目3，我们将使用单- 细胞转录组学（核心D）和蛋白质组学/代谢组学（核心C）分析，以确定 细胞外SASP因子对神经元、星形胶质细胞和小胶质细胞NAD水平、NAD水解酶表达和 NAD生物合成途径、增殖和其他表型标志物。 目的3：确定NAD水解酶CD 38的全身和组织特异性敲低的效果 神经元、星形胶质细胞和小胶质细胞在小鼠AD疾病进展中的作用。我们将使用新开发的 组织特异性CD 38敲除小鼠系，以测试CD 38在AD中脑的每种主要细胞类型中的作用 鼠标模型背景。

PROJECT SUMMARY Aging and Alzheimer's disease (AD) and related dementia are accompanied by striking changes in systemic and cellular metabolism. Several recently published results support the model that changes in NAD metabolism plays a role in AD and that restoration of NAD levels via NAD boosters protect against disease progression. The enzyme CD38 consumes NAD, increases during aging and mice lacking CD38 are protected from age-related NAD decline. CD38 levels increase in the brain during disease progression in a double transgenic mouse model of AD (APP and presenilin-1). Remarkably, deleting CD38 in the APP.PS AD mouse model decreased amyloid- ß plaques and improved spatial learning, compared to wild-type mice. Our own new observations indicate that supernatants from senescent cells (SASP) activate CD38 expression in macrophages. These findings suggest a direct and causal link between senescence, the SASP and aging-associated decreases in cognitive function during AD via changes in NAD levels. Our working hypothesis is that senescent cells in the brain induce NAD decrease by inducing the expression of CD38 via their senescence-associated secretory phenotype (SASP). We propose: Aim 1. To determine the NAD metabolome of neurons, astrocytes, and microglia in mouse models of AD, in senescent cell cultures and in AD patient tissue samples. Using flow cytometry, single-cell transcriptomics (with Core D), proteomic/metabolomics analysis (with Core C), and IHC/IF immunostaining, we will measure NAD levels and protein expression levels of metabolic enzymes that regulate NAD metabolism in neurons, astrocytes, and microglia after induction of senescence in culture and in mouse models of AD and AD patient brain tissues. Aim 2: To determine the effect of cellular senescence and SASPs on NAD metabolism, proliferation, using co-cultured microglia, astrocytes and neurons. With Core B and Projects 1 and 3, we will use single- cell transcriptomics (Core D) and proteomic/metabolomics (Core C) analysis to determine the effect of extracellular SASP factors on neuron, astrocyte, and microglia NAD levels, expression of NAD hydrolases and NAD biosynthetic pathways, proliferation, and other phenotypical markers. Aim 3: To determine the effect of whole body and tissue-specific knockdown of the NAD hydrolase CD38 in neurons, astrocytes, and microglia in AD disease progression in mice. We will use a newly developed tissue-specific CD38 knockout mouse line to test the role of CD38 in each main cell type of the brain in AD mouse model backgrounds.