Samorì Elisa, Rodríguez Inmaculada, Oliver José Antonio, Sánchez-Vázquez Francisco Javier, López-Olmeda José Fernando
Department of Physiology, Faculty of Biology, University of Murcia, 30100, Murcia, Spain.
Fish Physiol Biochem. 2025 Feb 13;51(1):50. doi: 10.1007/s10695-025-01461-7.
The circadian system plays a crucial role in most physiological processes. The molecular clock is linked to epigenetic mechanisms, both of which are influenced by nutrient status and, consequently, to feeding. This research investigated how feeding times (mid-light, ML, vs. mid-dark, MD) synchronize daily rhythms of behavior, clock genes, and epigenetic mechanisms in the European sea bass (Dicentrarchus labrax), focusing on hypothalamus and liver to assess the impact on central and peripheral pacemakers. Feeding at MD influenced the molecular clock of the hypothalamus, causing shifts in acrophases (peaks) for genes of the negative loop (per1b, per2, cry1a). In the liver, the ML fed group showed rhythmic expression for all clock genes, whereas only per2 maintained the rhythms in the MD group. Epigenetic genes related to methylation (dnmt1, dnmt3a) and demethylation (tet2, gadd45aa, mbd4) in the liver displayed rhythmic expression in the ML group, but only dnmt3a maintained the rhythm in the MD group. Nutrient-related factors (SAM and SAH) showed differences between day and night, suggesting a different utilization based on feeding times. Finally, sirt1, a gene involved in deacetylation, displayed a clear daily rhythm in the ML group. All epigenetic genes peaked during the night (resting phase). Overall, these findings indicated feeding time serves as a potent zeitgeber, synchronizing circadian clock and epigenetic rhythms in the liver, with peaks during the resting phase, suggesting this phase represents the adequate time for epigenetic modifications.
昼夜节律系统在大多数生理过程中起着至关重要的作用。分子时钟与表观遗传机制相关联，这两者都受营养状况影响，进而受进食影响。本研究调查了喂食时间（光照中期，ML，与黑暗中期，MD）如何使欧洲海鲈（Dicentrarchus labrax）的行为、时钟基因和表观遗传机制的日常节律同步，重点关注下丘脑和肝脏，以评估对中枢和外周起搏器的影响。在MD时间喂食会影响下丘脑的分子时钟，导致负反馈环基因（per1b、per2、cry1a）的峰值相位发生变化。在肝脏中，ML喂食组的所有时钟基因均表现出节律性表达，而MD组只有per2保持节律。肝脏中与甲基化（dnmt1、dnmt3a）和去甲基化（tet2、gadd45aa、mbd4）相关的表观遗传基因在ML组表现出节律性表达，但MD组只有dnmt3a保持节律。营养相关因子（SAM和SAH）在白天和黑夜之间存在差异，表明基于喂食时间的利用方式不同。最后，参与去乙酰化的基因sirt1在ML组表现出明显的每日节律。所有表观遗传基因在夜间（休息期）达到峰值。总体而言，这些发现表明喂食时间是一种强大的授时因子，使肝脏中的昼夜节律时钟和表观遗传节律同步，在休息期达到峰值，表明这个阶段是进行表观遗传修饰的合适时间。
