scholarly journals Rhythmic regulation of DNA methylation factors and core-clock genes in brain structures activated by cocaine or sucrose

2021 ◽  
Author(s):  
Lamis Saad ◽  
Andries Kalsbeek ◽  
Jean Zwiller ◽  
Patrick Anglard
Keyword(s):  
Dna Methylation ◽  
Circadian Rhythms ◽  
Cytosine Methylation ◽  
Drugs Of Abuse ◽  
Clock Genes ◽  
Chronic Administration ◽  
Reward System ◽  
Brain Structures ◽  
Time Of Day ◽  
Dependent Manner

Abstract The circadian system interacts with the mesocorticolimbic reward system to modulate reward and memory in a time-of-day dependent manner. The circadian discrimination of reward however remains difficult to address between natural reinforcers and drugs of abuse. Circadian rhythms control cocaine sensitization and conversely cocaine causes long-term alteration in circadian periodicity in part through the serotonergic neurotransmission. Since neural circuits activated by cocaine and natural reinforcers do not completely overlap, we compared the effect of cocaine with that of sucrose, a strong reinforcer in rodents, by using passive chronic administration. The expression of fifteen genes playing a major role in DNA methylation (Dnmts, Tets), circadian rhythms (Clock, Bmal1, Per1/2, Cry1/2, Rev-Erbβ, Dbp1), appetite and satiety (Orexin, Npy) was analyzed in dopamine projection areas like the prefrontal cortex, the caudate putamen, and the hypothalamus interconnected with the reward system. The corresponding proteins of two genes (Orexin, Per2) were examined by IHC. For many factors controlling various biological functions, striking opposite responses were found between the two reinforcers. Global DNA methylation analysis showed that cocaine increased, while sucrose decreased the cytosine methylation content. The data are consistent with a repression of critical core-clock genes by cocaine, suggesting that consequently both agents differentially modulate day/night cycles. Whether cocaine-induced changes are long lasting, or contribute to the establishment of drug addiction requires further neuroepigenetic investigation. Understanding the mechanisms dissociating drugs of abuse from natural reinforcers remains a prerequisite for the design of selective therapeutic tools for compulsive behaviors.

scholarly journals Rhythmic Regulation of DNA Methylation Factors and Core-Clock Genes in Brain Structures Activated by Cocaine or Sucrose: Potential Role of Chromatin Remodeling

Genes ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 1195
Author(s):  
Lamis Saad ◽  
Andries Kalsbeek ◽  
Jean Zwiller ◽  
Patrick Anglard
Keyword(s):  
Dna Methylation ◽  
Circadian Rhythms ◽  
Chromatin Remodeling ◽  
Drugs Of Abuse ◽  
Clock Genes ◽  
Chronic Administration ◽  
Reward System ◽  
Brain Structures ◽  
Time Of Day ◽  
Dependent Manner

The circadian system interacts with the mesocorticolimbic reward system to modulate reward and memory in a time-of-day dependent manner. The circadian discrimination of reward, however, remains difficult to address between natural reinforcers and drugs of abuse. Circadian rhythms control cocaine sensitization and conversely cocaine causes long-term alteration in circadian periodicity in part through the serotonergic neurotransmission. Since neural circuits activated by cocaine and natural reinforcers do not completely overlap, we compared the effect of cocaine with that of sucrose, a strong reinforcer in rodents, by using passive chronic administration. The expression of fifteen genes playing a major role in DNA methylation (Dnmts, Tets), circadian rhythms (Clock, Bmal1, Per1/2, Cry1/2, Rev-Erbβ, Dbp1), appetite, and satiety (Orexin, Npy) was analyzed in dopamine projection areas like the prefrontal cortex, the caudate putamen, and the hypothalamus interconnected with the reward system. The corresponding proteins of two genes (Orexin, Per2) were examined by IHC. For many factors controlling biological and cognitive functions, striking opposite responses were found between the two reinforcers, notably for genes controlling DNA methylation/demethylation processes and in global DNA methylation involved in chromatin remodeling. The data are consistent with a repression of critical core-clock genes by cocaine, suggesting that, consequently, both agents differentially modulate day/night cycles. Whether observed cocaine and sucrose-induced changes in DNA methylation in a time dependent manner are long lasting or contribute to the establishment of addiction requires further neuroepigenetic investigation. Understanding the mechanisms dissociating drugs of abuse from natural reinforcers remains a prerequisite for the design of selective therapeutic tools for compulsive behaviors.

scholarly journals Time of Day Regulates Renal Mineralocorticoid Receptor Transcriptional Control of Electrolyte Balance

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A819-A820
Author(s):  
Monica Kanki ◽  
James Morgan ◽  
Peter J Fuller ◽  
Morag Jennifer Young
Keyword(s):  
Circadian Clock ◽  
Mineralocorticoid Receptor ◽  
Target Genes ◽  
Clock Genes ◽  
Rest Period ◽  
Time Of Day ◽  
Cardiac Cells ◽  
Electrolyte Balance ◽  
Dependent Manner ◽  
Peripheral Tissues

Abstract The mineralocorticoid receptor (MR) has an established role in blood pressure control and cardiovascular homeostasis via many actions in the heart and kidney. We recently identified a role for the MR in controlling the circadian clock in cardiac cells and demonstrated that time-of-day impacts MR activation in the heart. While time dependent behaviours such as upright posture and fluid intake control aldosterone release via the renin-angiotensin-aldosterone system (RAAS), we hypothesise that the circadian clock controls aldosterone signalling by modifying MR transcriptional outcomes. Two established MR target genes and core circadian clock genes are period 1 (Per1) and period 2 (Per2). We have previously shown that a bolus dose of aldosterone (i.p.) induced cardiac expression of Per1 and Per2 in wildtype mice treated at 8AM (start of rest period) but not when administered at 8PM (start of active period). Whether MR activation in the kidney is similarly dependent on time of day and aligns with MR actions in the heart remains to be assessed. We also sought to determine if the MR directly regulates the molecular clock in a ligand-dependent manner. In contrast to the heart, renal Per1 and Per2 expression was not upregulated at four hours following aldosterone administration at either 8AM or 8PM. Interestingly, aldosterone administered at 8AM, but not at 8PM, significantly down-regulated expression of the circadian clock gene, nuclear receptor reverse strand c-ERBA (ReverbA); ReverbA was not regulated in the heart following aldosterone treatment. Investigation of renal-MR target genes involved in sodium ion transfer, showed a down-regulation of epithelial sodium channel 1 alpha (ENaC-α), by aldosterone administered only at 8AM. Conversely, aldosterone administered at 8AM induced gene expression of FKBP Prolyl Isomerase 5 (Fkbp5), an immunophilin that is important in nuclear trafficking of the MR. These data provide new insights for tissue sensitivity to MR activation in the heart and the kidney, which may play differing roles in contributing to regulating circadian patterns of several cardiovascular and renal parameters. Moreover, our data suggest that in addition to the accepted entrainment role of the glucocorticoid receptor (GR), the MR may also play a role in the entrainment of the circadian clock in peripheral tissues. Ongoing mechanistic studies will determine whether the MR can directly control the periodicity of the renal cellular clock, as it does in the heart. Key outcomes will be assessed in population databases to determine the clinical relevance of these findings. We propose that understanding of time-of-day dependent vulnerability to MR signalling in the heart versus the kidney may offer the rationale for the development of novel temporal or tissue specific-MR modulators in the management of cardiovascular disease.

Abstract 049: Role of Smooth Muscle BMAL1 in Time-of-day Vasoconstriction Variation and Blood Pressure Circadian Rhythm

Hypertension ◽  
2014 ◽  
Vol 64 (suppl_1) ◽  
Author(s):  
Zhongwen Xie ◽  
Wen Su ◽  
Shu Liu ◽  
Guogang Zhao ◽  
Karyn Esser ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Circadian Rhythm ◽  
Pulse Pressure ◽  
Clock Genes ◽  
Time Of Day ◽  
Mesenteric Arteries ◽  
Dependent Manner ◽  
Central Pacemaker

The blood pressure circadian rhythm was believed to be primarily controlled by the central pacemaker suprachiasmatic nucleus (SCN). This dogma was challenged by the discoveries that each of the clock genes present in the SCN are also expressed and function in peripheral tissues. But whether, and if so how, the peripheral clock genes are involved remains uncertain. The current study investigates the role of Bmal1, an obligatory core clock gene, plays in smooth muscle and blood pressure regulation by using a smooth muscle specific BMAL1 knockout mouse model (SM-Bmal1-KO). The results show: 1) Smooth muscle specific deletion of BMAL1 does not affect the clock genes in SCN but drastically suppresses the amplitude and the time-of day differences in vasoconstriction in response to various agonist stimulation and to perfusion pressure increase in isolated small mesenteric arteries and pressor responses in anesthetized mice; 2) The inhibition of agonist-induced vasoconstriction is associated with suppression of MLC 20 phosphorylation, ROCK2 mRNA and activity. Moreover, BMAL1 directly binds to ROCK2 promoter in a time-of-day dependent manner in mesenteric arteries and is required for ROCK2 promoter activity in cultured vascular smooth muscle cells; 3) Mice lacking smooth muscle BMAL1, but not those lacking cardiomyocyte BMAL1, exhibits alterations in blood pressure. SM-Bmal1-KO mice have moderately but significantly decreased blood pressure under 12:12 light/dark cycle, constant dark, and constant light conditions. The blood pressure circadian rhythm in SM-Bmal1-KO mice has diminished amplitude, forward shifted acrophase, but normal period length and normal locomotor activity; 4) interestingly, pulse pressure is markedly elevated and the pulse pressure circadian rhythm is abolished in the SM-Bmal1-KO mice. These data provide novel mechanistic insights into the daily control of vasoconstriction and blood pressure, which are fundamentally significant for the elucidation of pathogenesis of diseases involving blood pressure circadian rhythm disruption.

scholarly journals Entrainment of circadian rhythms depends on firing rates and neuropeptide release of VIP SCN neurons

2018 ◽  
Author(s):  
Cristina Mazuski ◽  
John H. Abel ◽  
Samantha P. Chen ◽  
Tracey O. Hermanstyne ◽  
Jeff R. Jones ◽  
...  
Keyword(s):  
Gene Expression ◽  
Circadian Rhythms ◽  
Time Of Day ◽  
Neuronal Firing ◽  
List Type ◽  
Dependent Manner ◽  
Firing Activity ◽  
Firing Patterns

SummaryThe mammalian suprachiasmatic nucleus (SCN) functions as a master circadian pacemaker, integrating environmental input to align physiological and behavioral rhythms to local time cues. Approximately 10% of SCN neurons express vasoactive intestinal polypeptide (VIP); however, it is unknown how firing activity of VIP neurons releases VIP to entrain circadian rhythms. To identify physiologically relevant firing patterns, we optically tagged VIP neurons and characterized spontaneous firing over three days. VIP neurons had circadian rhythms in firing rate and exhibited two classes of instantaneous firing activity. We next tested whether physiologically relevant firing affected circadian rhythms through VIP release. We found that VIP neuron stimulation with high, but not low, frequencies shifted gene expression rhythms in vitro through VIP signaling. In vivo, high frequency VIP neuron activation rapidly entrained circadian locomotor rhythms. Thus, increases in VIP neuronal firing frequency release VIP and entrain molecular and behavioral circadian rhythms.HighlightsMazuski et al. identified three classes of circadian SCN neurons based on their distinct firing patterns consistent over multiple daysThere are two distinct classes (tonic and irregular firing) of VIP SCN neurons.Stimulation of VIP SCN neurons at physiologically relevant frequencies phase shifts whole-SCN circadian rhythms in gene expression through VIP release. These effects are blocked with VIP antagonists.Firing of VIP SCN neurons entrains circadian rhythms in locomotor behavior in a frequency and time-of-day dependent manner.

scholarly journals Decitabine Inhibits Bone Resorption in Periodontitis by Upregulating Anti-Inflammatory Cytokines and Suppressing Osteoclastogenesis

Biomedicines ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 199
Author(s):  
Urara Tanaka ◽  
Shunichi Kajioka ◽  
Livia S. Finoti ◽  
Daniela B. Palioto ◽  
Denis F. Kinane ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Bone Resorption ◽  
Bone Loss ◽  
Inflammatory Cytokines ◽  
Osteoclast Differentiation ◽  
Tartrate Resistant Acid Phosphatase ◽  
Dependent Manner ◽  
Bone Homeostasis ◽  
Osteoblastic Cell Line ◽  
Anti Inflammatory

DNA methylation controls several inflammatory genes affecting bone homeostasis. Hitherto, inhibition of DNA methylation in vivo in the context of periodontitis and osteoclastogenesis has not been attempted. Ligature-induced periodontitis in C57BL/6J mice was induced by placing ligature for five days with Decitabine (5-aza-2′-deoxycytidine) (1 mg/kg/day) or vehicle treatment. We evaluated bone resorption, osteoclast differentiation by tartrate-resistant acid phosphatase (TRAP) and mRNA expression of anti-inflammatory molecules using cluster differentiation 14 positive (CD14+) monocytes from human peripheral blood. Our data showed that decitabine inhibited bone loss and osteoclast differentiation experimental periodontitis, and suppressed osteoclast CD14+ human monocytes; and conversely, that it increased bone mineralization in osteoblastic cell line MC3T3-E1 in a concentration-dependent manner. In addition to increasing IL10 (interleukin-10), TGFB (transforming growth factor beta-1) in CD14+ monocytes, decitabine upregulated KLF2 (Krüppel-like factor-2) expression. Overexpression of KLF2 protein enhanced the transcription of IL10 and TGFB. On the contrary, site-directed mutagenesis of KLF2 binding site in IL10 and TFGB abrogated luciferase activity in HEK293T cells. Decitabine reduces bone loss in a mouse model of periodontitis by inhibiting osteoclastogenesis through the upregulation of anti-inflammatory cytokines via KLF2 dependent mechanisms. DNA methyltransferase inhibitors merit further investigation as a possible novel therapy for periodontitis.

scholarly journals Epigenetic Modulation of TLR4 Expression by Sulforaphane Increases Anti-Inflammatory Capacity in Porcine Monocyte-Derived Dendritic Cells

Biology ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 490
Author(s):  
Xueqi Qu ◽  
Christiane Neuhoff ◽  
Mehmet Ulas Cinar ◽  
Maren Pröll ◽  
Ernst Tholen ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Dendritic Cells ◽  
Epigenetic Modifications ◽  
Dna Demethylation ◽  
Dependent Manner ◽  
Experimental Conditions ◽  
Hdac Activity ◽  
Protein Levels ◽  
Anti Inflammatory ◽  
Epigenetic Modulation

Inflammation is regulated by epigenetic modifications, including DNA methylation and histone acetylation. Sulforaphane (SFN), a histone deacetylase (HDAC) inhibitor, is also a potent immunomodulatory agent, but its anti-inflammatory functions through epigenetic modifications remain unclear. Therefore, this study aimed to investigate the epigenetic effects of SFN in maintaining the immunomodulatory homeostasis of innate immunity during acute inflammation. For this purpose, SFN-induced epigenetic changes and expression levels of immune-related genes in response to lipopolysaccharide (LPS) stimulation of monocyte-derived dendritic cells (moDCs) were analyzed. These results demonstrated that SFN inhibited HDAC activity and caused histone H3 and H4 acetylation. SFN treatment also induced DNA demethylation in the promoter region of the MHC-SLA1 gene, resulting in the upregulation of Toll-like receptor 4 (TLR4), MHC-SLA1, and inflammatory cytokines’ expression at 6 h of LPS stimulation. Moreover, the protein levels of cytokines in the cell culture supernatants were significantly inhibited by SFN pre-treatment followed by LPS stimulation in a time-dependent manner, suggesting that inhibition of HDAC activity and DNA methylation by SFN may restrict the excessive inflammatory cytokine availability in the extracellular environment. We postulate that SFN may exert a protective and anti-inflammatory function by epigenetically influencing signaling pathways in experimental conditions employing porcine moDCs.

scholarly journals Shared Components of the FRQ-Less Oscillator and TOR Pathway Maintain Rhythmicity in Neurospora

2021 ◽  
pp. 074873042199994
Author(s):  
Rosa Eskandari ◽  
Lalanthi Ratnayake ◽  
Patricia L. Lakin-Thomas
Keyword(s):  
Circadian Rhythms ◽  
Clock Genes ◽  
Nutrient Sensing ◽  
Mass Spectrometry Analysis ◽  
Growth Responses ◽  
Tor Pathway ◽  
Spectrometry Analysis ◽  
Binding Partner ◽  
Binding Partners ◽  
Free Running

Molecular models for the endogenous oscillators that drive circadian rhythms in eukaryotes center on rhythmic transcription/translation of a small number of “clock genes.” Although substantial evidence supports the concept that negative and positive transcription/translation feedback loops (TTFLs) are responsible for regulating the expression of these clock genes, certain rhythms in the filamentous fungus Neurospora crassa continue even when clock genes ( frq, wc-1, and wc-2) are not rhythmically expressed. Identification of the rhythmic processes operating outside of the TTFL has been a major unresolved area in circadian biology. Our lab previously identified a mutation ( vta) that abolishes FRQ-less rhythmicity of the conidiation rhythm and also affects rhythmicity when FRQ is functional. Further studies identified the vta gene product as a component of the TOR (Target of Rapamycin) nutrient-sensing pathway that is conserved in eukaryotes. We now report the discovery of TOR pathway components including GTR2 (homologous to the yeast protein Gtr2, and RAG C/D in mammals) as binding partners of VTA through co-immunoprecipitation (IP) and mass spectrometry analysis using a VTA-FLAG strain. Reciprocal IP with GTR2-FLAG found VTA as a binding partner. A Δ gtr2 strain was deficient in growth responses to amino acids. Free-running conidiation rhythms in a FRQ-less strain were abolished in Δ gtr2. Entrainment of a FRQ-less strain to cycles of heat pulses demonstrated that Δ gtr2 is defective in entrainment. In all of these assays, Δ gtr2 is similar to Δ vta. In addition, expression of GTR2 protein was found to be rhythmic across two circadian cycles, and functional VTA was required for GTR2 rhythmicity. FRQ protein exhibited the expected rhythm in the presence of GTR2 but the rhythmic level of FRQ dampened in the absence of GTR2. These results establish association of VTA with GTR2, and their role in maintaining functional circadian rhythms through the TOR pathway.

296 Sex differences in sleep and wakefulness of police officers working shifts: evidence from a field study

SLEEP ◽  
2021 ◽  
Vol 44 (Supplement_2) ◽  
pp. A118-A118
Author(s):  
Gabriela Caetano ◽  
Laura Kervezee ◽  
Fernando Gonzales-Aste ◽  
Philippe Boudreau ◽  
Diane Boivin
Keyword(s):  
Sex Differences ◽  
Circadian Rhythms ◽  
Shift Work ◽  
Police Officers ◽  
Field Studies ◽  
Time Of Day ◽  
Cycle Phase ◽  
Shift Workers ◽  
Work Related ◽  
Time Awake

Abstract Introduction National reports of work-related injuries found the excess risk of work injury attributed to shift work to be significantly higher among women. The Working Time Society (WTS) concluded that male sex is one of the few factors that is “consistently associated with perceived or actual shift work tolerance”. However, it is unclear if physiological parameters are involved. Laboratory-controlled studies report sex differences in circadian rhythms (body temperature, melatonin). In sleep deprivation protocols, alertness and cognitive performances were affected by sex, menstrual cycle phase and hormonal contraceptives [HC] use. Nevertheless, field studies that compare male and female shift workers are scarce. Methods An observational study including 76 police officers working on patrol: 56 males and 20 females (11 using [HC], 6 not using [non-HC] and 3 with unknown use of hormonal contraception) aged 32.0 ± 5.3 years. Participants were followed throughout a month-long work cycle (1,457 morning, evening, night, or other shifts, plus rest days). They filled out time-stamped questionnaires (Samn-Perelli, KSS, Visual Analogue Scales, ~5/day; sleep and work-related information, ~1–2/day), completed 5-min Psychomotor Vigilance Tasks (PVT, ~2/day), and wore an actigraph to collect activity data. Linear mixed-effects models were used to analyze the effects of group, time awake and time-of-day on fatigue, sleepiness, alertness, mood and PVT measures. Results Self-reported measures and psychomotor performance significantly varied with time awake and time-of-day. Fatigue and sleepiness levels were significantly higher among female compared to male police officers, both with time awake and across the 24-h day. These variations were similar between non-HC females and the other groups. Compared to males, HC females were more fatigued and less alert, both with time awake and across the 24-h day, and sleepier with time awake. Having children at home did not explain these differences. Conclusion The results of this study expand our knowledge on the sex differences in the sleep and circadian physiology and demonstrate a critical effect of HC on women fatigue, sleepiness and alertness when working shifts. Sex and hormonal parameters must be considered in occupational medicine as well as in future laboratory and field studies on shift workers and circadian rhythms. Support (if any) IRSST, FRQS.

scholarly journals DNA Methylation of Human Choline Kinase Alpha Promoter-Associated CpG Islands in MCF-7 Cells

Genes ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 853
Author(s):  
Siti Aisyah Faten Mohamed Sa’dom ◽  
Sweta Raikundalia ◽  
Shaharum Shamsuddin ◽  
Wei Cun See Too ◽  
Ling Ling Few
Keyword(s):  
Dna Methylation ◽  
Transcription Factor ◽  
Binding Site ◽  
Promoter Activity ◽  
Cytosine Methylation ◽  
Cpg Island ◽  
Cpg Islands ◽  
Site Directed Mutagenesis ◽  
Choline Kinase ◽  
Mcf 7

Choline kinase (CK) is the enzyme catalyzing the first reaction in CDP-choline pathway for the biosynthesis of phosphatidylcholine. Higher expression of the α isozyme of CK has been implicated in carcinogenesis, and inhibition or downregulation of CKα (CHKA) is a promising anticancer approach. This study aimed to investigate the regulation of CKα expression by DNA methylation of the CpG islands found on the promoter of this gene in MCF-7 cells. Four CpG islands have been predicted in the 2000 bp promoter region of ckα (chka) gene. Six CpG island deletion mutants were constructed using PCR site-directed mutagenesis method and cloned into pGL4.10 vectors for promoter activity assays. Deletion of CpG4C region located between –225 and –56 significantly increased the promoter activity by 4-fold, indicating the presence of important repressive transcription factor binding site. The promoter activity of methylated full-length promoter was significantly lower than the methylated CpG4C deletion mutant by 16-fold. The results show that DNA methylation of CpG4C promotes the binding of the transcription factor that suppresses the promoter activity. Electrophoretic mobility shift assay analysis showed that cytosine methylation at MZF1 binding site in CpG4C increased the binding of putative MZF1 in nuclear extract. In conclusion, the results suggest that DNA methylation decreased the promoter activity by promoting the binding of putative MZF1 transcription factor at CpG4C region of the ckα gene promoter.

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