Transcriptome profiling of circadian day and night gene expression in the suprachiasmatic nucleus of hypophysectomized (HPX) and control (non-HPX) mice
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE226929 | GEO | 2023/10/16
REPOSITORIES: GEO
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Project description:The mammalian master circadian pacemaker within the suprachiasmatic nucleus (SCN) maintains tight entrainment to the 24 hr light/dark cycle via a sophisticated clock-gated rhythm in the responsiveness of the oscillator to light. Intriguingly, entrainment is not merely a passive response, instead the internal oscillator responds and adjust its own timing to entrainment signals discriminating the time of day. For example, exposure to brief light pulses in the first and final hours of the subjective generate circadian phase delays and advances respectively; whereas similar photic pulses during the subjective day does not modify the phase. A central event in this light entrainment process appears to be the rapid induction of gene expression via the ERK/MAPK pathway. We used microarray-based expression profiling of the suprachiasmatic nucleus to examine the role of MAPK signaling in the light-evoked transcriptional response. We focused on three circadian timepoints that define the unique, clock-time delimited response properties of the SCN to light: the subjective day, early subjective night, and late subjective night.
2021-03-24 | GSE165799 | GEO
Project description:Although the mammalian rest-activity cycle is controlled by a "master clock" in the suprachiasmatic nuclei (SCN) of the hypothalamus, it is unclear how firing of individual SCN neurons gates individual features of daily activity. Here, we demonstrate that a specific transcriptomically identified population of mouse VIP+ SCN neurons is active at the "wrong" time of the day -nighttime- when most SCN neurons are silent. Using chemogenetic and optogenetic strategies, we show that these neurons and their cellular clocks are necessary and sufficient to gate and time nighttime sleep, but have no effect upon daytime sleep. We propose mouse nighttime sleep, analogous to the human siesta, is a "hard-wired" property gated by specific neurons of the master clock to favor subsequent alertness prior to dawn (a circadian "wake maintenance zone"). Thus, the SCN is not simply a 24h metronome: specific populations sculpt critical features of the sleep-wake cycle.
2021-01-21 | GSE154038 | GEO
Project description:Chronic jet lag induces spontaneous hepatocellular carcinoma (HCC) in wild-type mice following a pathophysiological pathway very similar to that observed in obese humans. This process initiates with non-alcoholic fatty liver disease (NAFLD), progresses to steatohepatitis and fibrosis before HCC detection, and is driven by persistent genome-wide gene deregulation that induces global liver metabolic dysfunction. Nuclear receptor-controlled cholesterol/bile acid and xenobiotic metabolism are found among top deregulated pathways. Ablation of the bile acid receptor FXR dramatically increases intrahepatic bile acid levels and jet-lag-induced HCC, while loss of CAR, a well-known liver tumor promoter, inhibits NAFLD-induced hepatocarcinogenesis. Circadian disruption activates CAR by promoting cholestasis, peripheral clock disruption, and sympathetic dysfunction. Thus, FXR and CAR are clock-controlled therapeutic targets for spontaneous HCC
2016-11-23 | GSE75475 | GEO
Project description:The aim of our study was to investigate the circadian regulation of cellular processes in mouse choroid plexus (ChP) and to determine their dependence on signals from the clock in the suprachiasmatic nuclei (SCN). We performed time-resolved transcriptomics of ChP samples from C57Bl6J mice with intact (Ctrl) or surgically removed SCN (SCNx) collected every 4 h over 2 days in constant darkness and from FoxJ1-ERT2-Cre+/-; Bmal1fl/fl mice with ChP-specific clock disruption (Bmal1-KO) collected at 2 time points. We found widespread circadian gene expression in Ctrl mice that was not present in SCNx mice, and the SCNx day/night ratios were reduced similarly to Bmal1-KO.
2023-09-30 | GSE243858 | GEO
Project description:The brain’s suprachiasmatic nucleus (SCN) is the master clock driving circadian rhythms in mammals. Vasoactive intestinal polypeptide (VIP) and its cognate receptor, VPAC2, are expressed in SCN neurons and mice with genetically targeted deletion of VPAC2 (Vipr2 -/-animals) show aberrant resetting to light, abnormal behavioral rhythms, and diminished SCN clock gene expression. Timed daily access to a running-wheel (scheduled voluntary exercise; SVE) promotes Vipr2 -/- SCN clock cell synchrony and 24h behavioral rhythms. We hypothesized that timed exercise alters the SCN transcriptome. Here, in control (Vipr2+/+) and Vipr2-/- mice under freely exercising and SVE conditions, RNAseq and qRT-PCR were used to measured gene expression of laser-dissected SCN. Compared to Vipr2+/+ mice, hundreds of genes were differentially expressed in the SCN from Vipr2-/- mice rhythmic in the freely exercising condition. Unexpectedly, SVE did not promote a Vipr2+/+-like SCN transcriptome in Vipr2-/- mice and many transcripts involved in SCN function including Avp, C1ql3, Gpr176, Prok2, Sst, Per2, and Nr1d1 remained dysregulated in the SVE condition. By contrast, circadian oscillators in the liver and lung were mostly intact in Vipr2-/- mice. This study indicates that marked molecular deficits in the SCN are sustained in behaviorally rhythmic Vipr2-/- mice, raising the possibility that a minimal functional SCN circadian clock can underpin whole animal rhythms.
2023-01-20 | GSE207992 | GEO
Project description:The suprachiasmatic nucleus (SCN) acts as the central clock to coordinate circadian oscillations in mammalian behavior, physiology and gene expression. Despite our knowledge of the circadian transcriptome of the SCN, how it impacts genome-wide protein expression is not well understood. Here, we interrogated the murine SCN proteome across the circadian cycle using SILAC-based quantitative mass spectrometry.
2014-09-10 | PXD000778 | Pride
Project description:The timing of daily “circadian” behavior can be highly variable among different individuals, and twin studies suggest that about half of this variability is environmentally controlled. Similar plasticity can be seen in mice exposed to an altered lighting environment – for example, 22-hour days instead of 24-hour ones – which stably alters the genetically determined period of circadian behavior for months. The mechanisms mediating these environmental influences are unknown. Here, we show that transient exposure of mice to such lighting stably alters global transcription in the suprachiasmatic nucleus of the hypothalamus (the SCN, the “master clock” tissue determining circadian behavior in mammals). We have also showed that, these changes in transcription are due to change in DNA methylation in the SCN. Indeed, genome-wide methylation profiling revealed global alterations in promoter DNA methylation in the SCN. Importantly, infusion of a methyltransferase inhibitor to the SCN during 22-hour days suppressed period changes. We also found that these behavioral and DNA methylation changes are reversible upon entrainment to 24-hours days. We conclude that the SCN utilizes DNA methylation as a mechanism to drive circadian clock plasticity. MeDIP array of profiling, demonstrated that genomicDNA methylation changes in mice entrained to short-T cycle.
2014-01-14 | GSE54021 | GEO
Project description:One hundred ninety wildtype male C57BL/6J mice age 7-10 weeks were purchased from Jackson Laboratory and entrained to a 12:12 light:dark cycle for 2 weeks. Mice were placed in light-tight boxes on a 12:12 LD cycle for 4 weeks, then released into constant darkness. Starting 30 hours after entry into DD (CT18), tissues from 5 (skeletal muscle) or 10 (liver or SCN) wildtype mice were collected every 4 hours for 48 hours, for a total of 12 timepoints. At timepoints 34 through 58 hours in DD, tissues from age-matched male C57BL/6J Clock/Clock homozygous mutant mice that had been treated with the same light entrainment protocol as the wildtype were collected. Tissues were collected from 5 Clock/Clock mutants at each timepoint except for 34 and 46 hours after the onset of DD, when tissues from 10 Clock/Clock mice were collected and run as independent replicates. Mice were sacrificed by cervical dislocation, and the optic nerves were severed in complete darkness; brain dissection was performed using illumination from an infrared viewer (FJW Industries, Palatine, IL). SCNs were dissected out, pooled at a density of 5 per tube in 100 ?l RNAlater (Ambion, Austin, TX), frozen on dry ice, and stored at â80?C until use. Keywords: time course duplicates consisted of pools from independent mice
2010-06-11 | E-GEOD-3748 | biostudies-arrayexpress
Project description:One hundred ninety wildtype male C57BL/6J mice age 7-10 weeks were purchased from Jackson Laboratory and entrained to a 12:12 light:dark cycle for 2 weeks. Mice were placed in light-tight boxes on a 12:12 LD cycle for 4 weeks, then released into constant darkness. Starting 30 hours after entry into DD (CT18), tissues from 5 (skeletal muscle) or 10 (liver or SCN) wildtype mice were collected every 4 hours for 48 hours, for a total of 12 timepoints. At timepoints 34 through 58 hours in DD, tissues from age-matched male C57BL/6J Clock/Clock homozygous mutant mice that had been treated with the same light entrainment protocol as the wildtype were collected. Tissues were collected from 5 Clock/Clock mutants at each timepoint except for 34 and 46 hours after the onset of DD, when tissues from 10 Clock/Clock mice were collected and run as independent replicates. Mice were sacrificed by cervical dislocation, and the optic nerves were severed in complete darkness; brain dissection was performed using illumination from an infrared viewer (FJW Industries, Palatine, IL). SCNs were dissected out, pooled at a density of 5 per tube in 100 ul RNAlater (Ambion, Austin, TX), frozen on dry ice, and stored at â80 degrees C until use. Keywords: SuperSeries This reference Series links data in the following related Series: GSE3746 Circadian skeletal muscle_wt and Clock mutants GSE3748 Circadian liver_wt and Clock mutants
2010-06-12 | E-GEOD-3751 | biostudies-arrayexpress
Project description:Circadian disruption, as shift work, is associated with metabolic diseases, including obesity and fatty liver, often attributed to discordance between internal clocks and environmental timekeepers1-5. However, this desynchrony hypothesis has not been rigorously tested. The body’s master clock, located in the suprachiasmatic nucleus (SCN), synchronizes peripheral clocks and ultimately metabolism2,6. Molecular clocks are comprised of transcriptional translational feedback loops involving gene activation by BMAL1, which is rhythmically repressed by separate mechanisms involving PER/CRY and REV-ERB nuclear receptors. Mice harboring whole body deletion of REV-ERBa/b have been reported to be arrhythmic7. However, we report here that mice lacking REV-ERBs specifically in the SCN maintain free-running and metabolic rhythms, but these are strikingly shortened by nearly 3 hours. When housed under a 24 hours light-dark cycle and fed an obesogenic diet, these mice gained excess weight and accrued more liver fat than controls. Remarkably, these metabolic disturbances were corrected by matching environmental lighting to the shortened endogenous clock period. Thus, SCN REV-ERBs are not required to maintain rhythmicity but powerfully control the free-running period. Moreover, these results support the hypothesis that dissonance between environmental conditions and endogenous period causes metabolic disruption. This has important implications for chronotherapy of metabolic and behavioral disorders.
2021-07-15 | GSE152919 | GEO