跑台运动通过抑制小胶质细胞NAMPT表达并上调NAD+/SIRT1通路改善AD小鼠海马线粒体功能

Treadmill Exercise Inhibits Microglial NAMPT Expression and Upregulates NAD+/SIRT1 Pathway to Improve Mitochondrial Function in the Hippocampus of AD Mice

目的:探讨12周有氧跑台运动对APP/PS1小鼠海马小胶质细胞NAMPT表达的影响及其在调节NAD^(+)/SIRT1/FOXO1/3a信号通路改善线粒体功能障碍中的作用。方法:3月龄野生型C57BL/6小鼠和APP/PS1小鼠随机分为野生型对照组(WT-sed)、野生型运动组(WT-exe)和APP/PS1对照组(AD-sed)、APP/PS1运动组(AD-exe)。运动组进行为期12周的有氧跑台运动干预。干预结束后,采用Morris水迷宫检测小鼠学习记忆能力,免疫荧光检测小鼠海马Iba-1表达水平及NAMPT与Iba-1共定位水平,透射电镜检测小鼠海马线粒体超微结构,Western blot检测海马SIRT1、Ace-FOXO1/3a、PARP1、CD38蛋白表达水平,RT-PCR检测线粒体DNA(mitochondrial DNA,mtDNA)、PARP1、CD38 mRNA表达水平,ELISA和试剂盒检测NAD^(+)、NADH、IL-1β、IL-6、TNF-α、ATP、H_(2)O_(2)的含量。结果:与WT-sed组相比,AD-sed组小鼠海马NAMPT与Iba-1共定位水平、PARP1、CD38、Ace-FOXO1/3a蛋白表达水平、IL-6、IL-1β、TNF-α、H_(2)O_(2)含量及受损线粒体数量均显著升高,NAD^(+)含量、NAD^(+)/NADH比值、SIRT1蛋白表达水平、mtDNA拷贝数、ATP含量及学习记忆能力均显著降低,而12周有氧跑台运动干预显著改善了APP/PS1小鼠海马上述异常变化。结论:12周有氧跑台运动可能通过抑制小胶质细胞NAMPT过度表达,降低神经炎症反应,减少PARP1、CD38对NAD^(+)的消耗,上调NAD^(+)/SIRT1/FOXO1/3a信号通路,改善线粒体功能障碍,最终起到缓解APP/PS1小鼠学习记忆衰退的作用。

Objective:To investigate the effect of 12-week aerobic treadmill exercise on microglial NAMPT and its role in improving mitochondrial dysfunction through upregulating the NAD^(+)/SIRT1/FOXO1/3a signaling pathway in hippocampus of APP/PS1 mice.Methods:3-month-old wild type C57BL/6 mice and APP/PS1 mice were randomly divided into wild type control group(WT-sed),wild type exercise group(WT-exe),APP/PS1control group(AD-sed),and APP/PS1 exercise group(AD-exe).Mice in exercise group was conducted 12-week aerobic treadmill exercise intervention.After the intervention,morris water maze was used to detect the learning and memory abilities of mice.Immunofluorescence was used to measure the expression of Iba-1 expression and co-localization level of NAMPT and Iba-1 in hippocampal microglia.The hippocampal mitochondrial ultrastructure was detected by the transmission electron microscopy.Western blot was used to detect the protein expression levels of SIRT1,Ace-FOXO1/3a,PARP1,and CD38 in the hippocampus.RT-PCR was used to detect the mRNA expression levels of mtDNA,PARP1,and CD38.ELISA and kit were used to detect the content of NAD^(+),NADH,IL-6,IL-1β,TNF-α,ATP,and H_(2)O_(2).Results:Compared with WT-sed,the levels of NAMPT and Iba-1 co-localization,PARP1,CD38,Ace-FOXO1/3a,IL-6,IL-1β,TNF-α,H_(2)O_(2) and the number of damaged mitochondria were significantly increased,but the NAD^(+)content,NAD^(+)/NADH ratio,SIRT1,mtDNA copy number,ATP content and learning and memory ability were significantly decreased in AD-sed mice.However,the 12-week aerobic treadmill exercise significantly improved the aforementioned abnormal changes in the hippocampus of APP/PS1 mice.Conclusions:12-week aerobic treadmill exercise intervention could inhibit the overexpression of NAMPT in microglia,reduce neuroinflammatory response,decrease the consumption of NAD^(+)by inhibiting PARP1 and CD38,and then upregulate the NAD^(+)/SIRT1/FOXO1/3a signaling pathway,improve mitochondrial dysfunction,and ultimately alleviate the decline of learning and memory in APP/PS1 mice.