Role and Possible Mechanism of Clock Gene Rev-erbα in Exercise-induced Mitochondrial Biogenesis / 生物化学与生物物理进展

The clock gene Rev-erbα, also known as nuclear receptor subfamily 1 group D member 1 (Nr1d1), is a crucial regulatory factor in organisms. It exhibits circadian rhythmic expression in metabolically active tissues such as skeletal muscles, heart, liver, and adipose tissue, responding to various environmental stimuli. Rev-erbα plays a significant role in regulating circadian rhythms, metabolic homeostasis, and other physiological processes, earning its designation as an “integrator” of the circadian system and metabolism. Rev-erbα establishes complex connections with other clock genes through the transcriptional-translational feedback loop (TTFL), which is important for the rhythmic output of biological clock system and for the relative stability of phases and cycles. Mitochondrial biogenesis is a physiological process initiated by cells to maintain energy homeostasis by using existing mitochondria as a template for self-growth and division. As the “energy factory” of organism, disruptions in mitochondrial biogenesis are closely associated with the development of various diseases. Studies have shown that not only the factors involved in mitochondrial biogenesis have circadian oscillations, but also the morphology, dynamics and energy metabolism of mitochondria themselves have cyclic fluctuations throughout the day, suggesting that mitochondrial biogenesis is regulated by the biological clock system, in which the clock gene Rev-erbα plays a key role, it drives mitochondrial biogenesis and synergistically regulates autophagy to normalize a number of physiological processes in the body. Rev-erbα is sensitive to both internal and external environmental changes, and disruptions in circadian rhythms, metabolic diseases, and aging are significant inducers of changes in Rev-erbα expression, and its concomitant inflammation and oxidative stress may be an intrinsic mechanism for inhibiting mitochondrial biogenesis. Therefore, the enhancement of mitochondrial biogenesis by regulating the Rev-erbα activity status may be an important way to improve the pathology and promote the health of organism. Exercise, as a commonly accepted non-pharmacological tool, plays an important role in enhancing mitochondrial biogenesis and promoting health. It has been found that there is a close relationship between exercise and Rev-erbα. On the one hand, exercise stimulation directly affects the expression of Rev-erbα, especially high-intensity and long-term regular exercise; on the other hand, Rev-erbα achieves indirect regulation of exercise capacity by mediating processes such as skeletal muscle mitochondrial biogenesis and autophagy, muscle mass maintenance, energy metabolism and skeletal muscle regeneration. Based on the above findings, it is hypothesized that Rev-erbα may serve as a key bridge between exercise and mitochondrial biogenesis. Exercise enhances the transcriptional response of Rev-erbα in the nucleus, upregulates the expression of Rev-erbα protein in cytoplasm, activates the AMP-activated proteinkinase (AMPK)/ silent information regulator 1 (SIRT1)/peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) pathway, regulates Ca2+ flux and downstream signaling molecules; meanwhile, exercise can upregulate antioxidant gene expression and alleviate oxidative stress through Rev-erbα, which ultimately enhances the function of mitochondria, and promotes mitochondrial biogenesis. In conclusion, the clock gene Rev-erbα emerges as a crucial target for exercise-induced enhancement of mitochondrial biogenesis. In this paper, the biological characteristics ofRev-erbα, the role of Rev-erbα in regulating mitochondrial biogenesis and the factors that may influence it, the interaction between exercise and Rev-erbα, and the potential mechanism of exercise-induced mitochondrial biogenesis via Rev-erbα are sorted out and discussed, which can provide theoretical references to the mechanism of exercise-promoted mitochondrial biogenesis.

Regulating effect of REV-ERBα on working memory after laparotomy and its mechanism in rats exposed to sleep deprivation / 中华神经医学杂志

Objective:To investigate the protective effect of REV-ERBα agonist SR9009 on hippocampal working memory in rats with acute rapid eye movement (REM) sleep deprivation after exploratory laparotomy and its possible mechanism.Methods:Ninety SD rats were randomly divided into control group, sleep deprivation group, exploratory laparotomy group, sleep deprivation+exploratory laparotomy group, and sleep deprivation+exploratory laparotomy+SR9009 group ( n=18). Rats in the sleep deprivation group, exploratory laparotomy group, and sleep deprivation+exploratory laparotomy group were given REM sleep deprivation for 96 h or (and) exploratory laparotomy, respectively. Rats in the sleep deprivation+exploratory laparotomy+SR9009 group accepted exploratory laparotomy after REM sleep deprivation for 96 h, and accepted intraperitoneal injection of 100 mg/kg SR9009 daily from the day after surgery to the 6 th d of surgery. The reversall escape latency of rats was recorded by contrapuntal space exploration training one-5 d after surgery. On the 5 th d of surgery, reversal space exploration experiment was conducted to record the number of times of rats crossing the original platform. Western blotting was used to detect the protein expressions of REV-ERBα and BMAL1 in the hippocampus of rats. The levels of interleukin (IL)-1β and IL-6 in the hippocampus of rats were detected by enzyme-linked immunosorbent assay. Immunofluorescent staining was used to detect the expressions of neuronal nucleoprotein (NeuN) and glial fibrillary acidic protein (GFAP). Results:(1) The escape latency in the sleep deprivation group, exploratory laparotomy group, and sleep deprivation+exploratory laparotomy group was significantly longer than that in the control group on the first, 2 nd, 3 rd, 4 th, 5 th d of surgery ( P<0.05); while the escape latency in the sleep deprivation group and sleep deprivation+exploratory laparotomy group was significantly longer than that in the exploratory laparotomy group ( P<0.05); on the 2 nd, 3 rd, 4 th, 5 th d of surgery, the reversal escape latency in the sleep deprivation+exploratory laparotomy+SR9009 group was statistically shorter than that in the sleep deprivation+exploratory laparotomy group ( P<0.05). The number of times of rats crossing the original platform in the sleep deprivation group, exploratory laparotomy group, and sleep deprivation+exploratory laparotomy group was significantly smaller than that of the control group ( P<0.05); that of rats in the sleep deprivation+exploratory laparotomy group was significantly smaller than that of the exploratory laparotomy group, and that of rats in the sleep deprivation+exploratory laparotomy+SR9009 group was significantly larger than that of the sleep deprivation+exploratory laparotomy group ( P<0.05). (2) As compared with the control group, the exploratory laparotomy group, sleep deprivation group and sleep deprivation+exploratory laparotomy group had significantly decreased expressions of REV-ERBα and BMAL1, and statistically increased IL-1β and IL-6 levels in the hippocampal tissues ( P<0.05); as compared with the sleep deprivation+exploratory laparotomy group, the sleep deprivation+exploratory laparotomy+SR9009 group had significantly increased expressions of REV-ERBα and BMAL1, and statistically decreased IL-1β and IL-6 levels ( P<0.05). (3) As compared with the control group, the exploratory laparotomy group, sleep deprivation group and sleep deprivation+exploratory laparotomy group had decreased amount of neurons in the hippocampal CA3 area and increased amount of activated astrocytes; as compared with the sleep deprivation+exploratory laparotomy group, the sleep deprivation+exploratory laparotomy+SR9009 group had increased amount of neurons in the hippocampal CA3 area and decreased amount of activated astrocytes. Conclusion:Acute REM sleep deprivation can lead to work memory impairment in rats accepted exploratory laparotomy, which might be associated with neuroinflammation and REV-ERBα/BMAL1 pathway, and SR9009 could alleviate the damage.

Mildly Increased Mechanical Nociceptive Sensitivity in REV-ERBα Knock-out Mice

Nociception is one of the most complex senses that is affected not only by external stimulation but also internal conditions. Previous studies have suggested that circadian rhythm is important in modulating nociception. REV-ERBα knock-out (KO) mice have disrupted circadian rhythm and altered mood-related phenotypes. In this study, we examined the role of REV-ERBα in inflammatory nociception. We found that the nociceptive sensitivity of KO mice was partially enhanced in mechanical nociception. However, this partial alteration was independent of the circadian rhythm. Taken together, deletion of REV-ERBα induced a mild change in mechanical nociceptive sensitivity but this alteration was not dependent on the circadian rhythm.

Suprachiasmatic nucleus slices induce molecular oscillations in fibroblasts / 中华行为医学与脑科学杂志

Objective To study whether suprachiasmatic nucleus (SCN) slices are able to induce the molecular oscillations in NIH/3T3 fibroblast. Methods SCN slices from 10-day-old SD rat and NIH/3T3 cells were co-cultured in a serum-free condition. 24h mRNA profiles of Per1 and Rev-Erbα were measured in NIH/3T3 cells using real-time PCR. Results After co-cultured for 6 days, ten SCN slices can induce the significant daily oscillation of Per1 and Rev-Erba mRNA expression in NIH/3T3 cells (P<0.01). The peak time Rev-erbα and Per1 were at CT5 and CT11 respectively. Rev-Erbα oscillations were significant even with two SCN slices and 2 days co-culture (P<0.05). In contrast, Per1 expression fluctuation was not observed until more than 6 days of co-culture and with six SCN slices (P=0.031). Conclusion Diffusible signals release from SCN slices can regulate molecular rhythms in cultured fibroblasts. Rev-Erbα and Per1 don't start to oscillate at the same time, and Rev-Erbα is more sensitive to SCN signal.