School of Human Biology, University of Western Australia, Crawley, 6009, Australia.
School of Human Biology, University of Western Australia, Crawley, 6009, Australia.
J Therm Biol. 2021 Aug;100:102983. doi: 10.1016/j.jtherbio.2021.102983. Epub 2021 May 1.
Temperature rhythms can act as potent signals for the modulation of the amplitude and phase of clock gene expression in peripheral organs in vitro, but the relevance of the circadian rhythm of core body temperature (T) as a modulating signal in vivo has not yet been investigated. Using calorie restriction and cafeteria feeding, we induced a larger and a dampened T amplitude, respectively, in male Wistar rats, and investigated the circadian expression profile of the core clock genes Bmal1, Per2, Cry1, and Rev-erbα, the heat-responsive genes heat shock protein 90 (Hsp90) and cold-inducible RNA binding protein (Cirbp), and Pgc1α, Pparα/γ/δ, Glut1/4, and Chop10 in the liver, skeletal muscle, white adipose tissue (WAT), and adrenal glands. Diet-altered T rhythms differentially affected the profiles of clock genes, Hsp90, and Cirbp expression in peripheral tissues. Greater T amplitudes elicited by calorie restriction were associated with large amplitudes of Hsp90 and Cirbp expression in the liver and WAT, in which larger amplitudes of clock gene expression were also observed. The amplitudes of metabolic gene expression were greater in the WAT, but not in the liver, in calorie-restricted rats. Conversely, diet-altered T rhythms were not translated to distinct changes in the amplitude of Hsp90, Cirbp, or clock or metabolic genes in the skeletal muscle or adrenal glands. While it was not possible to disentangle the effects of diet and temperature in this model, taken together with previous in vitro studies, our study presents novel data consistent with the notion that the circadian T rhythm can modulate the amplitude of circadian gene expression in vivo. The different responses of Hsp90 and Cirbp in peripheral tissues may be linked to the tissue-specific responses of peripheral clocks to diet and/or body temperature rhythms, but the association with the amplitude of metabolic gene expression is limited to the WAT.
温度节律可以作为体外调节外周器官时钟基因表达幅度和相位的有效信号，但核心体温（T）昼夜节律作为体内调节信号的相关性尚未得到研究。我们使用热量限制和 cafeteria 喂养分别诱导雄性 Wistar 大鼠的 T 幅度增大和减弱，研究了核心时钟基因 Bmal1、Per2、Cry1 和 Rev-erbα、热响应基因热休克蛋白 90（Hsp90）和冷诱导 RNA 结合蛋白（Cirbp）以及 Pgc1α、Pparα/γ/δ、Glut1/4 和 Chop10 在肝脏、骨骼肌、白色脂肪组织（WAT）和肾上腺中的昼夜表达谱。改变饮食的 T 节律对周围组织的时钟基因、Hsp90 和 Cirbp 表达谱有不同的影响。热量限制引起的 T 幅度增大与肝脏和 WAT 中 Hsp90 和 Cirbp 表达幅度增大有关，同时也观察到时钟基因表达幅度增大。在热量限制的大鼠中，WAT 中的代谢基因表达幅度更大，但在肝脏中则不然。相反，饮食改变的 T 节律在骨骼肌或肾上腺中并没有导致 Hsp90、Cirbp、时钟或代谢基因表达幅度的明显变化。虽然在这个模型中无法区分饮食和温度的影响，但结合以前的体外研究，我们的研究提供了新的数据，与昼夜 T 节律可以调节体内昼夜基因表达幅度的观点一致。外周组织中 Hsp90 和 Cirbp 的不同反应可能与外周时钟对饮食和/或体温节律的组织特异性反应有关，但与代谢基因表达幅度的关联仅限于 WAT。
