Abstract：
OBJECTIVE: Napping is a common habit in many countries. Nevertheless, studies about the chronic effects of napping on obesity are contradictory, and the molecular link between napping and metabolic alterations has yet to be studied. We aim to identify molecular mechanisms in adipose tissue (AT) that may connect napping and abdominal obesity.
METHODS: In this cross-sectional study, we extracted the RNA repeatedly across 24h from cultured AT explants and performed RNA sequencing. Circadian rhythms were analyzed using 6 consecutive time points across 24 hours. We also assessed global gene expression in each group (nappers vs. non-nappers).
RESULTS: With napping, there was a loss of rhythmicity in 88% of genes that showed circadian rhythmicity among non-nappers, a reduction in rhythm amplitudes of 29%, and significant phase changes from a coherent unimodal acrophase in non-nappers, towards a scattered and bimodal acrophase in nappers. Those genes that lost rhythmicity with napping were mainly involved in pathways of glucose and lipid metabolism, and of the circadian clock. Additionally, we found differential global gene expression between nappers and non-nappers with 34 genes down- and 32 genes up-regulated in nappers. The top up-regulated gene (IER3) and top down-regulated pseudogene (VDAC2P2) in nappers have been previously shown to be involved in inflammation.
CONCLUSIONS: These new findings may have implications for our understanding of napping\'s effects on obesity and metabolic disorders.
METHODS: In this cross-sectional study, we extracted the RNA repeatedly across 24h from cultured AT explants and performed RNA sequencing. Circadian rhythms were analyzed using 6 consecutive time points across 24 hours. We also assessed global gene expression in each group (nappers vs. non-nappers).
RESULTS: With napping, there was a loss of rhythmicity in 88% of genes that showed circadian rhythmicity among non-nappers, a reduction in rhythm amplitudes of 29%, and significant phase changes from a coherent unimodal acrophase in non-nappers, towards a scattered and bimodal acrophase in nappers. Those genes that lost rhythmicity with napping were mainly involved in pathways of glucose and lipid metabolism, and of the circadian clock. Additionally, we found differential global gene expression between nappers and non-nappers with 34 genes down- and 32 genes up-regulated in nappers. The top up-regulated gene (IER3) and top down-regulated pseudogene (VDAC2P2) in nappers have been previously shown to be involved in inflammation.
CONCLUSIONS: These new findings may have implications for our understanding of napping\'s effects on obesity and metabolic disorders.
摘要：
目的：午睡是许多国家的普遍习惯。然而，关于午睡对肥胖的慢性影响的研究是相互矛盾的，午睡和代谢改变之间的分子联系还有待研究。我们旨在确定脂肪组织（AT）中可能连接打盹和腹部肥胖的分子机制。
方法：在这项横断面研究中，我们从培养的AT外植体中重复提取RNA，并进行RNA测序。使用24小时内的6个连续时间点分析昼夜节律。我们还评估了每组的整体基因表达(napersvs.非午睡者)。
结果：午睡，在非睡眠者中显示昼夜节律的基因中，有88％的节律性丧失，节律振幅减少29%,和显著的相位变化，从一个连贯的单峰顶阶段在非睡眠，朝向小睡者中分散的双峰顶相。那些因午睡而失去节律的基因主要参与葡萄糖和脂质代谢途径，和生物钟。此外,我们发现napers和非napers之间的全球基因表达差异，其中34个基因在napers中下调，32个基因在napers中上调。先前已显示napers中的顶部上调基因（IER3）和顶部下调假基因（VDAC2P2）与炎症有关。
结论：这些新发现可能对我们理解午睡对肥胖和代谢紊乱的影响有意义。
方法：在这项横断面研究中，我们从培养的AT外植体中重复提取RNA，并进行RNA测序。使用24小时内的6个连续时间点分析昼夜节律。我们还评估了每组的整体基因表达(napersvs.非午睡者)。
结果：午睡，在非睡眠者中显示昼夜节律的基因中，有88％的节律性丧失，节律振幅减少29%,和显著的相位变化，从一个连贯的单峰顶阶段在非睡眠，朝向小睡者中分散的双峰顶相。那些因午睡而失去节律的基因主要参与葡萄糖和脂质代谢途径，和生物钟。此外,我们发现napers和非napers之间的全球基因表达差异，其中34个基因在napers中下调，32个基因在napers中上调。先前已显示napers中的顶部上调基因（IER3）和顶部下调假基因（VDAC2P2）与炎症有关。
结论：这些新发现可能对我们理解午睡对肥胖和代谢紊乱的影响有意义。
