scholarly journals Does a Red House Affect Rhythms in Mice with a Corrupted Circadian System?

2021 ◽  
Vol 22 (5) ◽  
pp. 2288
Author(s):  
Menekse Öztürk ◽  
Marc Ingenwerth ◽  
Martin Sager ◽  
Charlotte von Gall ◽  
Amira A. H. Ali
Keyword(s):  
Circadian Rhythms ◽  
Neuronal Activity ◽  
Clock Genes ◽  
Plasma Corticosterone ◽  
Cellular Level ◽  
Circadian System ◽  
Targeted Deletion ◽  
Long Wavelength ◽  
And Behavior ◽  
Time Information

The circadian rhythms of body functions in mammals are controlled by the circadian system. The suprachiasmatic nucleus (SCN) in the hypothalamus orchestrates subordinate oscillators. Time information is conveyed from the retina to the SCN to coordinate an organism’s physiology and behavior with the light/dark cycle. At the cellular level, molecular clockwork composed of interlocked transcriptional/translational feedback loops of clock genes drives rhythmic gene expression. Mice with targeted deletion of the essential clock gene Bmal1 (Bmal1−/−) have an impaired light input pathway into the circadian system and show a loss of circadian rhythms. The red house (RH) is an animal welfare measure widely used for rodents as a hiding place. Red plastic provides light at a low irradiance and long wavelength—conditions which affect the circadian system. It is not known yet whether the RH affects rhythmic behavior in mice with a corrupted circadian system. Here, we analyzed whether the RH affects spontaneous locomotor activity in Bmal1−/− mice under standard laboratory light conditions. In addition, mPER1- and p-ERK-immunoreactions, as markers for rhythmic SCN neuronal activity, and day/night plasma corticosterone levels were evaluated. Our findings indicate that application of the RH to Bmal1−/− abolishes rhythmic locomotor behavior and dampens rhythmic SCN neuronal activity. However, RH had no effect on the day/night difference in corticosterone levels.

scholarly journals Circadian Clock and The Cardiometabolic Risk

2010 ◽  
Vol 2 (2) ◽  
pp. 16
Author(s):  
Anna Meiliana ◽  
Andi Wijaya
Keyword(s):  
Circadian Rhythms ◽  
Cardiometabolic Risk ◽  
Clock Genes ◽  
Epidemiological Data ◽  
Circadian System ◽  
Temporal Organization ◽  
Liver Fat ◽  
Peripheral Tissues ◽  
The Central Nervous System ◽  
Rotation Of The Earth

BACKGROUND: Epidemiological data reveal parallel trends of decreasing sleep duration and increases in metabolic disorders such as obesity, diabetes and hypertension. There is growing evidence that these trends are mechanistically related.CONTENT: The circadian system orchestrates the temporal organization of many aspects of physiology, including metabolism, in synchrony with the 24 hours rotation of the Earth. The circadian system is a complex feedback network that involves interactions between the central nervous system and peripheral tissues. Circadian regulation is intimately linked to metabolic homeostasis and that dysregulation of circadian rhythms can contribute to disease. Conversely, metabolic signals also feed back into the circadian system, modulating circadian gene expression and behavior.SUMMARY: Both inter- and intraorgan desynchrony may be involved in the pathogenesis of cardiometabolic disease attributable to effects in brain and multiple metabolic tissues including heart, liver, fat, muscle, pancreas and gut. Efforts to dissect the molecular mediators that coordinate circadian, metabolic, and cardiovascular systems may ultimately lead to both improved therapeutics and preventive interventions.KEYWORDS: circadian rhythms, clock genes, nuclear receptor, sleep, obesity, cardiometabolic risk

scholarly journals Roles of Neuropeptides, VIP and AVP, in the Mammalian Central Circadian Clock

2021 ◽  
Vol 15 ◽  
Author(s):  
Daisuke Ono ◽  
Ken-ichi Honma ◽  
Sato Honma
Keyword(s):  
Transcription Factors ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Cellular Networks ◽  
Clock Genes ◽  
Circadian System ◽  
Developmental Changes ◽  
Circadian Period ◽  
Functional Roles ◽  
Environmental Light

In mammals, the central circadian clock is located in the suprachiasmatic nucleus (SCN) of the hypothalamus. Individual SCN cells exhibit intrinsic oscillations, and their circadian period and robustness are different cell by cell in the absence of cellular coupling, indicating that cellular coupling is important for coherent circadian rhythms in the SCN. Several neuropeptides such as arginine vasopressin (AVP) and vasoactive intestinal polypeptide (VIP) are expressed in the SCN, where these neuropeptides function as synchronizers and are important for entrainment to environmental light and for determining the circadian period. These neuropeptides are also related to developmental changes of the circadian system of the SCN. Transcription factors are required for the formation of neuropeptide-related neuronal networks. Although VIP is critical for synchrony of circadian rhythms in the neonatal SCN, it is not required for synchrony in the embryonic SCN. During postnatal development, the clock genes cryptochrome (Cry)1 and Cry2 are involved in the maturation of cellular networks, and AVP is involved in SCN networks. This mini-review focuses on the functional roles of neuropeptides in the SCN based on recent findings in the literature.

scholarly journals The Clock Takes Shape—24 h Dynamics in Genome Topology

2022 ◽  
Vol 9 ◽  
Author(s):  
Kévin Tartour ◽  
Kiran Padmanabhan
Keyword(s):  
Gene Expression ◽  
Circadian Rhythms ◽  
Metabolic Diseases ◽  
Cell Metabolism ◽  
Cellular Level ◽  
Damage Response ◽  
And Behavior ◽  
Open Question ◽  
Daily Changes

Circadian rhythms orchestrate organismal physiology and behavior in order to anticipate daily changes in the environment. Virtually all cells have an internal rhythm that is synchronized every day by Zeitgebers (environmental cues). The synchrony between clocks within the animal enables the fitness and the health of organisms. Conversely, disruption of rhythms is linked to a variety of disorders: aging, cancer, metabolic diseases, and psychological disorders among others. At the cellular level, mammalian circadian rhythms are built on several layers of complexity. The transcriptional-translational feedback loop (TTFL) was the first to be described in the 90s. Thereafter oscillations in epigenetic marks highlighted the role of chromatin state in organizing the TTFL. More recently, studies on the 3D organization of the genome suggest that genome topology could be yet another layer of control on cellular circadian rhythms. The dynamic nature of genome topology over a solar day implies that the 3D mammalian genome has to be considered in the fourth dimension-in time. Whether oscillations in genome topology are a consequence of 24 h gene-expression or a driver of transcriptional cycles remains an open question. All said and done, circadian clock-gated phenomena such as gene expression, DNA damage response, cell metabolism and animal behavior—go hand in hand with 24 h rhythms in genome topology.

scholarly journals Dissociation of Per1 and Bmal1 circadian rhythms in the suprachiasmatic nucleus in parallel with behavioral outputs

2017 ◽  
Vol 114 (18) ◽  
pp. E3699-E3708 ◽  
Author(s):  
Daisuke Ono ◽  
Sato Honma ◽  
Yoshihiro Nakajima ◽  
Shigeru Kuroda ◽  
Ryosuke Enoki ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Behavioral Rhythm ◽  
Calcium Indicator ◽  
Intracellular Ca ◽  
Regional Specificity ◽  
Free Running ◽  
Activity Onset ◽  
And Behavior

The temporal order of physiology and behavior in mammals is primarily regulated by the circadian pacemaker located in the hypothalamic suprachiasmatic nucleus (SCN). Taking advantage of bioluminescence reporters, we monitored the circadian rhythms of the expression of clock genes Per1 and Bmal1 in the SCN of freely moving mice and found that the rate of phase shifts induced by a single light pulse was different in the two rhythms. The Per1-luc rhythm was phase-delayed instantaneously by the light presented at the subjective evening in parallel with the activity onset of behavioral rhythm, whereas the Bmal1-ELuc rhythm was phase-delayed gradually, similar to the activity offset. The dissociation was confirmed in cultured SCN slices of mice carrying both Per1-luc and Bmal1-ELuc reporters. The two rhythms in a single SCN slice showed significantly different periods in a long-term (3 wk) culture and were internally desynchronized. Regional specificity in the SCN was not detected for the period of Per1-luc and Bmal1-ELuc rhythms. Furthermore, neither is synchronized with circadian intracellular Ca2+ rhythms monitored by a calcium indicator, GCaMP6s, or with firing rhythms monitored on a multielectrode array dish, although the coupling between the circadian firing and Ca2+ rhythms persisted during culture. These findings indicate that the expressions of two key clock genes, Per1 and Bmal1, in the SCN are regulated in such a way that they may adopt different phases and free-running periods relative to each other and are respectively associated with the expression of activity onset and offset.

scholarly journals Regulation of Melanopsins andPer1byα-MSH and Melatonin in PhotosensitiveXenopus laevisMelanophores

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Maria Nathália de Carvalho Magalhães Moraes ◽  
Luciane Rogéria dos Santos ◽  
Nathana Mezzalira ◽  
Maristela Oliveira Poletini ◽  
Ana Maria de Lauro Castrucci
Keyword(s):  
Gene Expression ◽  
Circadian Rhythms ◽  
Intracellular Signaling ◽  
Cultured Cells ◽  
Clock Genes ◽  
Circadian System ◽  
Time Of Application ◽  
Intracellular Signaling Pathways ◽  
Peripheral Clocks ◽  
Internal Signal

α-MSH and light exert a dispersing effect on pigment granules ofXenopus laevismelanophores; however, the intracellular signaling pathways are different. Melatonin, a hormone that functions as an internal signal of darkness for the organism, has opposite effects, aggregating the melanin granules. Because light functions as an important synchronizing signal for circadian rhythms, we further investigated the effects of both hormones on genes related to the circadian system, namely,Per1(one of the clock genes) and the melanopsins,Opn4xandOpn4m(photopigments).Per1showed temporal oscillations, regardless of the presence of melatonin orα-MSH, which slightly inhibited its expression. Melatonin effects on melanopsins depend on the time of application: if applied in the photophase it dramatically decreasedOpn4xandOpn4mexpressions, and abolished their temporal oscillations, opposite toα-MSH, which increased the melanopsins’ expressions. Our results demonstrate that unlike what has been reported for other peripheral clocks and cultured cells, medium changes or hormones do not play a major role in synchronizing theXenopusmelanophore population. This difference is probably due to the fact thatX. laevismelanophores possess functional photopigments (melanopsins) that enable these cells to primarily respond to light, which triggers melanin dispersion and modulates gene expression.

scholarly journals Disruption of Circadian Rhythms: A Crucial Factor in the Etiology of Depression

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
Roberto Salgado-Delgado ◽  
Araceli Tapia Osorio ◽  
Nadia Saderi ◽  
Carolina Escobar
Keyword(s):  
Circadian Rhythms ◽  
Biological Clock ◽  
Therapeutic Strategies ◽  
Circadian System ◽  
Metabolic Functions ◽  
Lighting Conditions ◽  
Wide Range ◽  
Close Relationship ◽  
And Behavior ◽  
Depressive States

Circadian factors might play a crucial role in the etiology of depression. It has been demonstrated that the disruption of circadian rhythms by lighting conditions and lifestyle predisposes individuals to a wide range of mood disorders, including impulsivity, mania and depression. Also, associated with depression, there is the impairment of circadian rhythmicity of behavioral, endocrine, and metabolic functions. Inspite of this close relationship between both processes, the complex relationship between the biological clock and the incidence of depressive symptoms is far from being understood. The efficiency and the timing of treatments based on chronotherapy (e.g., light treatment, sleep deprivation, and scheduled medication) indicate that the circadian system is an essential target in the therapy of depression. The aim of the present review is to analyze the biological and clinical data that link depression with the disruption of circadian rhythms, emphasizing the contribution of circadian desynchrony. Therefore, we examine the conditions that may lead to circadian disruption of physiology and behavior as described in depressive states, and, according to this approach, we discuss therapeutic strategies aimed at treating the circadian system and depression.

Molecular Biology and Physiology of Circadian Clocks

2019 ◽  
Author(s):  
Ruifeng Cao
Keyword(s):  
Circadian Rhythms ◽  
Circadian System ◽  
Feedback Loops ◽  
The Body ◽  
Endogenous Rhythms ◽  
Peripheral Oscillators ◽  
Physiological Processes ◽  
And Behavior ◽  
Photic Input ◽  
Master Clock

Circadian rhythm is the approximately 24-hour rhythmicity that regulates physiology and behavior in a variety of organisms. The mammalian circadian system is organized in a hierarchical manner. Molecular circadian oscillations driven by genetic feedback loops are found in individual cells, whereas circadian rhythms in different systems of the body are orchestrated by the master clock in the suprachiasmatic nucleus (SCN) of the anterior hypothalamus. SCN receives photic input from retina and synchronizes endogenous rhythms with the external light/dark cycles. SCN regulates circadian rhythms in the peripheral oscillators via neural and humoral signals, which account for daily fluctuations of the physiological processes in these organs. Disruption of circadian rhythms can cause health problems and circadian dysfunction has been linked to many human diseases.

9. Evolution and another look at the clock

2017 ◽  
pp. 122-130
Author(s):  
Russell G. Foster ◽  
Leon Kreitzman
Keyword(s):  
Circadian Rhythms ◽  
Empirical Evidence ◽  
Clock Genes ◽  
Internal Clock ◽  
Circadian System ◽  
Mrna Levels ◽  
Vital Importance ◽  
Living Things ◽  
History Of ◽  
Molecular Components

‘Evolution and another look at the clock’ concludes that the circadian system controls every key aspect of biochemistry, physiology, and behaviour. All plants, fungi, protista, algae, invertebrates, vertebrates, cyanobacteria, and at least one archaeon display circadian rhythms. These rhythms have many molecular components conserved between diverse species and are thought to be generated by molecular transcription–translation feedback loops in which a group of core clock genes regulate each other to ensure that their mRNA levels oscillate with a period of approximately 24 hours. Although the empirical evidence has been difficult to demonstrate, there is a consensus that the internal clock has been of vital importance in the evolutionary history of living things.

scholarly journals Light Pollution and Cancer

2020 ◽  
Vol 21 (24) ◽  
pp. 9360
Author(s):  
William H. Walker ◽  
Jacob R. Bumgarner ◽  
James C. Walton ◽  
Jennifer A. Liu ◽  
O. Hecmarie Meléndez-Fernández ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Metabolic Disorders ◽  
Clock Genes ◽  
Science Literature ◽  
Light At Night ◽  
Clock System ◽  
Industrialized Nations ◽  
Circadian Organization ◽  
And Behavior ◽  
Improve Health

For many individuals in industrialized nations, the widespread adoption of electric lighting has dramatically affected the circadian organization of physiology and behavior. Although initially assumed to be innocuous, exposure to artificial light at night (ALAN) is associated with several disorders, including increased incidence of cancer, metabolic disorders, and mood disorders. Within this review, we present a brief overview of the molecular circadian clock system and the importance of maintaining fidelity to bright days and dark nights. We describe the interrelation between core clock genes and the cell cycle, as well as the contribution of clock genes to oncogenesis. Next, we review the clinical implications of disrupted circadian rhythms on cancer, followed by a section on the foundational science literature on the effects of light at night and cancer. Finally, we provide some strategies for mitigation of disrupted circadian rhythms to improve health.

scholarly journals Circadian rhythms identified inCaenorhabditis elegansby in vivo long-term monitoring of a bioluminescent reporter

2016 ◽  
Vol 113 (48) ◽  
pp. E7837-E7845 ◽  
Author(s):  
María Eugenia Goya ◽  
Andrés Romanowski ◽  
Carlos S. Caldart ◽  
Claire Y. Bénard ◽  
Diego A. Golombek
Keyword(s):  
Circadian Rhythms ◽  
Circadian System ◽  
Phase Changes ◽  
Model Systems ◽  
Biological Variables ◽  
Evolutionarily Conserved ◽  
Gated Channel ◽  
Bioluminescence Assay ◽  
And Behavior

Circadian rhythms are based on endogenous clocks that allow organisms to adjust their physiology and behavior by entrainment to the solar day and, in turn, to select the optimal times for most biological variables. Diverse model systems—including mice, flies, fungi, plants, and bacteria—have provided important insights into the mechanisms of circadian rhythmicity. However, the general principles that govern the circadian clock ofCaenorhabditis eleganshave remained largely elusive. Here we report robust molecular circadian rhythms inC.elegansrecorded with a bioluminescence assay in vivo and demonstrate the main features of the circadian system of the nematode. By constructing a luciferase-based reporter coupled to the promoter of the suppressor of activatedlet-60Ras (sur-5) gene, we show in both population and single-nematode assays thatC.elegansexpresses ∼24-h rhythms that can be entrained by light/dark and temperature cycles. We provide evidence that these rhythms are temperature-compensated and can be re-entrained after phase changes of the synchronizing agents. In addition, we demonstrate that light and temperature sensing requires the photoreceptors LITE and GUR-3, and the cyclic nucleotide-gated channel subunit TAX-2. Our results shed light onC.eleganscircadian biology and demonstrate evolutionarily conserved features in the circadian system of the nematode.

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