Department of Physiology, Regional Campus of International Excellence, University of Murcia, Murcia, Spain.
Biomedical Research Institute of Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB)-Arrixaca-Universidad de Murcia (UMU), University Clinical Hospital, Murcia, Spain.
Sleep. 2024 Nov 8;47(11). doi: 10.1093/sleep/zsae160.
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.
In this cross-sectional study, we extracted the RNA repeatedly across 24 hours from cultured AT explants and performed RNA sequencing. Circadian rhythms were analyzed using six consecutive time points across 24 hours. We also assessed global gene expression in each group (nappers vs. non-nappers).
With napping, there was an 88% decrease in the number of rhythmic genes compared to that in 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 upregulated in nappers. The top upregulated gene (IER3) and top down-regulated pseudogene (VDAC2P2) in nappers have been previously shown to be involved in inflammation.
These new findings have implications for our understanding of napping's relationship with obesity and metabolic disorders.
打盹是许多国家的常见习惯。然而，关于打盹对肥胖的慢性影响的研究结果相互矛盾，且打盹与代谢改变之间的分子联系尚未得到研究。我们旨在确定脂肪组织（AT）中可能与打盹和腹部肥胖相关的分子机制。
在这项横断面研究中，我们从培养的 AT 外植体中反复提取 24 小时内的 RNA，并进行 RNA 测序。使用 24 小时内的连续 6 个时间点分析昼夜节律。我们还评估了每组（打盹者与非打盹者）的整体基因表达。
与非打盹者相比，打盹者的节律基因数量减少了 88%，节律幅度降低了 29%，相位变化明显，从非打盹者的连贯单峰相变为打盹者的分散双峰相。那些随打盹而失去节律性的基因主要涉及葡萄糖和脂质代谢以及昼夜节律途径。此外，我们发现打盹者和非打盹者之间存在差异的整体基因表达，其中 34 个基因下调，32 个基因上调。打盹者中上调最多的基因（IER3）和下调最多的假基因（VDAC2P2）之前已被证明与炎症有关。
这些新发现对我们理解打盹与肥胖和代谢紊乱之间的关系具有重要意义。
