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

项目总结 衰老和阿尔茨海默病(AD)和相关痴呆伴随着全身和 细胞新陈代谢。最近发表的几个结果支持NAD新陈代谢的变化起作用的模型 在AD中的作用以及通过NAD助推剂恢复NAD水平以防止疾病进展。这个 CD38酶消耗NAD，在衰老过程中增加，缺乏CD38的小鼠受到保护，不受年龄相关的影响 NAD拒绝。双转基因小鼠疾病进展过程中脑内CD38水平升高 AD组(APP和早老素-1)。值得注意的是，在APP.PS AD小鼠模型中，删除CD38可以减少淀粉样蛋白- 与野生型小鼠相比，它们有明显的斑块和改善的空间学习能力。我们自己的新观察表明 衰老细胞上清液(SASP)可激活巨噬细胞CD38的表达。这些发现表明 衰老、SASP和衰老相关的认知功能下降之间的直接和因果联系 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会导致NAD 通过其衰老相关分泌表型(SASP)诱导CD38的表达。我们 建议： 目的1.测定AD模型小鼠神经元、星形胶质细胞和小胶质细胞的NAD代谢组。 在衰老细胞培养和阿尔茨海默病患者组织样本中。利用流式细胞术，单细胞转录组 (核心D)、蛋白质组/代谢组学分析(核心C)和IHC/IF免疫染色，我们将测量 调节神经元中NAD代谢的代谢酶的NAD水平和蛋白表达水平， 在AD和AD患者模型中诱导衰老的星形胶质细胞和小胶质细胞 脑组织。 目的2：研究细胞衰老和SASP对NAD代谢、细胞增殖和细胞周期的影响。 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以及项目1和3，我们将使用单一- 细胞转录组学(核心D)和蛋白质组/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CD38对全身和组织特异性敲除的影响 在小鼠阿尔茨海默病进展中的神经元、星形胶质细胞和小胶质细胞。我们将使用一种新开发的 组织特异性CD38基因敲除小鼠品系检测CD38在阿尔茨海默病各主要脑细胞类型中的作用 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.