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Gene expressions in the muscle of wild-type and Clock/Clock mice. Transcript levels of Dec1 (A), Dec2 (B), Per2 (C), and Dbp (D) were determined by real time RT-PCR for 3 individual mice for each time point. Data are shown as mean ± SEM (n = 3). Dbp expression patterns of Clock/Clock mice are also shown in inset of D with an expanded ordinate. Other experimental conditions and abbreviations are the same as those described in the legend to Figure 1.
Source publication
DEC1 and DEC2-basic helix-loop-helix transcription factors-exhibit a circadian expression in the suprachiasmatic nucleus and other peripheral tissues and seem to play roles in regulating the mammalian circadian rhythm by suppressing the CLOCK/BMAL1-activated promoters of Per1, Dec1, and Dec2. The authors present data on the expression patterns of m...
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Citations
... Other key molecular cogs of the circadian clock circuitry are the bHLH transcription factors differentially expressed in chondrocytes protein 1 (DEC1) and 2 (DEC2), which interplay with the core clock proteins. In particular, DEC1 and DEC2 transcription is activated by ARNTL:NPAS2 and ARNTL:CLOCK heterodimers, but in sequence DEC1 and DEC2 proteins block their transcriptional activity, managing a feedback steering circuit [39,40,45]. The functioning of the molecular clockwork is finely tuned through rhythmic chromatin-histone remodeling and epigenetic modifications, principally geared up by acetylation/deacetylation and methylation/demethylation processes [46]. ...
Simple Summary
NPAS2, short for Neuronal PAS Domain Protein 2, is a transcription factor involved in regulating the circadian rhythms and sleep–wake cycles in mammals, including humans. It is a key component of the molecular clockwork that governs daily biological processes. NPAS2 binds heme as a prosthetic group and CO at micromolar concentrations, with ensuing changes in DNA affinity. In this way, gaseous signaling plus heme-based sensing and redox balance modify NPAS2 transcriptional activity and the expression of target genes. NPAS2 plays a crucial role in metabolism regulation and in maintaining the body’s internal clock synchronized with the day–night cycle. Dysregulation of NPAS2 can lead to disruptions in circadian rhythms and may contribute to sleep disturbances, psychiatric disorders and other health issues, such as neoplastic, cardiovascular and cerebrovascular diseases. Alternatively, NPAS2 could represent a valuable predictive biomarker for prevention/stratification strategies and a promising druggable target for innovative therapeutic approaches.
Abstract
Neuronal PAS domain protein 2 (NPAS2) is a hemeprotein comprising a basic helix–loop–helix domain (bHLH) and two heme-binding sites, the PAS-A and PAS-B domains. This protein acts as a pyridine nucleotide-dependent and gas-responsive CO-dependent transcription factor and is encoded by a gene whose expression fluctuates with circadian rhythmicity. NPAS2 is a core cog of the molecular clockwork and plays a regulatory role on metabolic pathways, is important for the function of the central nervous system in mammals, and is involved in carcinogenesis as well as in normal biological functions and processes, such as cardiovascular function and wound healing. We reviewed the scientific literature addressing the various facets of NPAS2 and framing this gene/protein in several and very different research and clinical fields.
... Other molecular cogs of the biological clock are the basic helix-loophelix transcription factors Differentially expressed in chondrocytes protein 1 (DEC1) and 2 (DEC2), 3 which interplay with the core clock proteins. In particular, DEC1 and DEC2 transcription is activated by ARNTL:NPAS2 and ARNTL:CLOCK heterodimer, but in sequence DEC1 and DEC2 proteins block their transcriptional activity, managing a feed-back steering circuit [19][20][21]. The functioning of the molecular clockwork is finely tuned through rhythmic chromatin-histone remodeling and epigenetic modifications principally geared up by acetylation/deacetylation and methylation/demethylation processes. ...
Neuronal PAS domain protein 2 (NPAS2) is a hemeprotein comprising a basic helix-loop-helix domain (bHLH) and two heme-binding sites, the PAS-A and PAS-B domains. This protein acts as a pyridine nucleotide-dependent and gas-responsive CO-dependent transcription factor and is encoded by a gene whose expression fluctuates with circadian rhythmicity. NPAS2 can heterodimerize with ARNTL in the activating limb of the transcriptional/translational feedback loop operating the circadian clock circuitry. NPAS2 can functionally substitute for the core transcription factor and histone/protein acetylase CLOCK in the molecular clockwork endowing central oscillators in the suprachiasmatic nuclei of hypothalamus as well as in peripheral oscillators in the cell of other body tissues, such as the liver and kidney.
... Biosystems). TaqMan probe and PCR primer sequences for Dbp, Reverbα, Dec2 and Dec1 were as previously described (Noshiro et al., 2005). Universal ProbeLibrary TaqMan probes (Roche) and primers for the other genes examined in this study were designed using ProbeFinder (Roche). ...
Previously, we found that the basic helix‐loop‐helix transcriptional repressor DEC1 interacts with the PPARγ:RXRα heterodimer, a master transcription factor for adipogenesis and lipogenesis, to suppress transcription from PPARγ target genes (Noshiro et. al., Genes to Cells, 2018, 23:658‐669). Because the expression of PPARγ and several of its target genes exhibits circadian rhythmicity in white adipose tissue (WAT), we examined the expression profiles of PPARγ target genes in wild‐type and Dec1−/− mice. We found that the expression of PPARγ target genes responsible for lipid metabolism, including the synthesis of triacylglycerol from free fatty acids (FFAs), lipid storage, and the lipolysis of triacylglycerol to FFAs, oscillates in a circadian manner in WAT. Moreover, DEC1 deficiency led to a marked increase in the expression of these genes at night (Zeitgeber times 16 and 22), resulting in disruption of circadian rhythms. Serum FFA levels in wild‐type mice also showed circadian oscillations, but these were disrupted by DEC1 deficiency, leading to reduced FFA levels. These results suggest that PPARγ:RXRα and DEC1 cooperatively generate the circadian expression of PPARγ target genes through PPAR‐responsive elements in WAT.
... Quantitative real-time RT-PCR analysis was carried out using the ABI PRISM 7900 Sequence Detection System (Applied Biosystems) as described (Gibson, Heid, & Williams, 1996). First-strand cDNA synthesis and the sequences of the primers and TaqMan ™ fluorogenic probes (Applied Biosystems) for mice Dec1 and Dec2 have been described previously (Noshiro et al., 2005). The sequences of the primers and TaqMan ™ fluorogenic probes for the other genes were designed using the ProbeFinder ™ software of the Roche Universal Probe Library system (Roche Applied Science). ...
Obesity is a major public health problem in developed countries resulting from increased food intake and decreased energy consumption and usually associated with abnormal lipid metabolism. Here, we show that DEC1, a basic helix‐loop‐helix transcription factor, plays an important role in the regulation of lipid consumption in mouse brown adipose tissue (BAT), which is the major site of thermogenesis. Homozygous Dec1 deletion attenuated high‐fat‐diet‐induced obesity, adipocyte hypertrophy, fat volume and hepatic steatosis. Furthermore, DEC1 deficiency increased body temperature during daytime and enhanced the expression of uncoupler protein 1, a key factor of thermogenesis, and various lipolysis‐related genes in interscapular BAT. In vitro experiments suggested that DEC1 suppresses the expression of various lipolysis‐related genes induced by the heterodimer of peroxisome proliferator‐activated receptor γ and retinoid X receptor α (RXRα) through direct binding to RXRα. These observations suggest that enhanced lipolysis in BAT caused by DEC1 deficiency leads to an increase in lipid consumption, thereby decreasing lipid accumulation in adipose tissues and the liver. Thus, DEC1 may serve as an energy‐saving factor that suppresses lipid consumption, which may be relevant to managing obesity.
... The link between GDAP1 and circadian gene expression is unknown. Because NPAS2 and DBP are antiphase to one another [54], our finding that these genes are regulated in opposing directions due to GDAP1 silencing is not surprising. Since DBP expression is elevated in liver of mice subjected to diet-induced obesity [55], the decrease due to GDAP1 silencing may be beneficial for metabolic In all panels, data were normalized to protein content, and all data are plotted for n ¼ 7 matched samples. ...
Objective:
We sought to identify AMPK-regulated genes via bioinformatic analysis of microarray data generated from skeletal muscle of animal models with genetically altered AMPK activity. We hypothesized that such genes would play a role in metabolism. Ganglioside-induced differentiation-associated protein 1 (GDAP1), a gene which plays a role in mitochondrial fission and peroxisomal function in neuronal cells but whose function in skeletal muscle is undescribed, was identified and further validated. AMPK activation reduced GDAP1 expression in skeletal muscle. GDAP1 expression was elevated in skeletal muscle from type 2 diabetic patients but decreased after acute exercise.
Methods:
The metabolic impact of GDAP1 silencing was determined in primary skeletal muscle cells via siRNA-transfections. Confocal microscopy was used to visualize whether silencing GDAP1 impacted mitochondrial network morphology and membrane potential.
Results:
GDAP1 silencing increased mitochondrial protein abundance, decreased palmitate oxidation, and decreased non-mitochondrial respiration. Mitochondrial morphology was unaltered by GDAP1 silencing. GDAP1 silencing and treatment of cells with AMPK agonists altered several genes in the core molecular clock machinery.
Conclusion:
We describe a role for GDAP1 in regulating mitochondrial proteins, circadian genes, and metabolic flux in skeletal muscle. Collectively, our results implicate GDAP1 in the circadian control of metabolism.
... Prepro-orexin expression and orexin levels show daily rhythms in hypothalamus and cerebrospinal fluid (24,25). DEC2 expression oscillates in a circadian manner (9,26) and thus may contribute to the expression rhythms of prepro-orexin. Our results suggest that E12/47, MyoD1, and DEC2 form a complex to regulate prepro-orexin expression. ...
Significance
Sleep is essential for healthy aging, and most people need approximately 8–8-1/2 hours of sleep per night to feel good and to function optimally. We previously reported a proline-to-arginine mutation in DEC2 that leads to a life-long decrease in daily sleep need. We found that the expression of an important sleep-relevant gene, orexin , was increased in the DEC2 mutant mice. Further investigation revealed that DEC2 is a transcriptional repressor for orexin expression, and that mutant DEC2 exerts less repressor activity than WT-DEC2, resulting in increased orexin expression. This study represents the first step toward understanding the underlying molecular mechanism through which DEC2 modulates sleep.
... For example, NPAS2 was reported to act as a homolog protein of Clock in mice. [29][30][31] However, we did not investigate these transcription factor in the UCs transfected with Clock siRNA. Although we observed that the time-dependent gene expression rhythm of clock genes, mechano-sensors, and ARMM genes were disrupted in UCs transfected with the Clock siRNA ( Figure 5), the gene expression pattern of TRPV4 seemed to show the rhythmicity ( Figure 5B). ...
Aims:
To investigate circadian gene expressions in the mouse bladder urothelium to establish an experimental model and study the functions of the circadian rhythm.
Methods:
The gene expression rhythms of the clock genes, mechano-sensors such as Piezo1 and TRPV4, ATP release mediated molecules (ARMM) such as Cx26 and VNUT were investigated in mouse primary cultured urothelial cells (UCs) of wild-type (WT) and Clock mutant (Clock(Δ19)(/Δ)(19) ) mice using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and western blotting analysis. The long-term oscillation of the clock genes in UC was investigated by measuring bioluminescence from UC isolated from Period2(luciferase) knock-in mice (Per2::luc) and Per2::luc with Clock(Δ19)(/Δ)(19) using a luminometer. The mRNA expression rhythms after treatment with Clock short interfering RNA (siRNA) were also measured to compare differences between Clock point mutations and Clock deficiency.
Results:
The UCs from WT mice showed the time-dependent gene expressions for clock genes, mechano-sensors, and ARMM. The abundances of the products of these genes also correlated with the mRNA expression rhythms in UCs. The bioluminescence of Per2::Luc in UCs showed a circadian rhythm. By contrast, all the gene expressions rhythms observed in WT mice were abrogated in the Clock(Δ19)(/Δ)(19) mice. Transfection with Clock siRNA in UCs had the same effect as the Clock mutation.
Conclusions:
We demonstrated that the time-dependent gene expressions, including clock genes, mechano-sensors, and ARMM, were reproducible in UCs. These findings demonstrated that UCs have the potential to progress research into the circadian functions of the lower urinary tract regulated by clock genes.
... Both transcription factors contain the bHLH structure, but not the PAS domain. The level of homology of DEC1 and DEC2 in the bHLH region is 97%, while that in the orange region (a motif of ~35 amino acids located C-terminally of the bHLH domain, providing an additional protein-protein interaction interface) is only 52% (59). In contrast to DEC1, the DEC2 transcription factor is rich in alanine and glycine, which may be one of the main reasons for their functional difference (59,60). ...
... The level of homology of DEC1 and DEC2 in the bHLH region is 97%, while that in the orange region (a motif of ~35 amino acids located C-terminally of the bHLH domain, providing an additional protein-protein interaction interface) is only 52% (59). In contrast to DEC1, the DEC2 transcription factor is rich in alanine and glycine, which may be one of the main reasons for their functional difference (59,60). DEC1 is widely expressed in multiple tissues, while the expression of DEC2 is highly tissue-dependent (59,60). ...
... In contrast to DEC1, the DEC2 transcription factor is rich in alanine and glycine, which may be one of the main reasons for their functional difference (59,60). DEC1 is widely expressed in multiple tissues, while the expression of DEC2 is highly tissue-dependent (59,60). DEC1 can downregulate and inhibit the activity of DEC2. ...
The circadian clock refers to the inherent biological rhythm of an organism, which, is accurately regulated by numerous clock genes. Studies in recent years have reported that the abnormal expression of clock genes is ubiquitous in common abdominal malignant tumors, including liver, colorectal, gastric and pancreatic cancer. In addition, the abnormal expression of certain clock genes is closely associated with clinical tumor parameters or patient prognosis. Studies in clock genes may expand the knowledge about the mechanism of occurrence and development of tumors, and may provide a new approach for tumor therapy. The present study summarizes the research progress in this field.
... The transcription factor DEC2 is important in the circadian rhythm, hypoxia response, differentiation and tumor progression (3,10,11,(17)(18)(19)(20)(21)(22)(23)(24). While DEC1 and DEC2 mRNA indicate a rhythmic expression in the suprachiasmatic nucleus (SCN), peripheral tissues, tumor cells and human mesenchymal stem cells (MSCs) (3,17,18,21,(25)(26)(27)(28)(29), whether DEC2 protein has rhythmic expression remains unclear. ...
Basic helix-loop-helix (bHLH) transcription factor DEC2 (bHLHE41/Sharp1) is one of the clock genes that show a circadian rhythm in various tissues. DEC2 regulates differentiation, sleep length, tumor cell invasion and apoptosis. Although studies have been conducted on the rhythmic expression of DEC2 mRNA in various tissues, the precise molecular mechanism of DEC2 expression is poorly understood. In the present study, we examined whether DEC2 protein had a rhythmic expression. Western blot analysis for DEC2 protein revealed a rhythmic expression in mouse liver, lung and muscle and in MCF-7 and U2OS cells. In addition, AMP-activated protein kinase (AMPK) activity (phosphorylation of AMPK) in mouse embryonic fibroblasts (MEFs) exhibited a rhythmic expression under the condition of medium change or glucose-depleted medium. However, the rhythmic expression of DEC2 in MEF gradually decreased in time under these conditions. The medium change affected the levels of DEC2 protein and phosphorylation of AMPK. In addition, the levels of DEC2 protein showed a rhythmic expression in vivo and in MCF-7 and U2OS cells. The results showed that the phosphorylation of AMPK immunoreactivity was strongly detected in the liver and lung of DEC2 knockout mice compared with that of wild-type mice. These results may provide new insights into rhythmic expression and the regulation between DEC2 protein and AMPK activity.
... The remaining proteins either make PER and CRY or DEC1 and DEC2 dimers and suppress the CLOCK/BMAL1 transactivation [3-6, 12, 13]. This negative feed-back system plays important roles in 24-hour rhythmic regulation for circadian rhythm in suprachiasmatic nucleus (SCN), peripheral tissues, or mesenchymal stem cells (MSCs) [14][15][16]. The disturbance of circadian rhythm may induce metabolic syndrome, diabetes, Alzheimer's disease, depression, sleep disorder, or cancer [17][18][19][20][21][22][23][24][25]. ...
