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 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 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 Differential Effects of Constant Light and Dim Light at Night on the Circadian Control of Metabolism and Behavior

2020 ◽  
Vol 21 (15) ◽  
pp. 5478 ◽  
Author(s):  
Valentina S. Rumanova ◽  
Monika Okuliarova ◽  
Michal Zeman
Keyword(s):  
Circadian Rhythms ◽  
Light Level ◽  
Constant Light ◽  
Signal Molecules ◽  
Light At Night ◽  
Circadian Control ◽  
Dim Light ◽  
Underlying Mechanisms ◽  
And Behavior ◽  
Light:Dark Cycle

The disruption of circadian rhythms by environmental conditions can induce alterations in body homeostasis, from behavior to metabolism. The light:dark cycle is the most reliable environmental agent, which entrains circadian rhythms, although its credibility has decreased because of the extensive use of artificial light at night. Light pollution can compromise performance and health, but underlying mechanisms are not fully understood. The present review assesses the consequences induced by constant light (LL) in comparison with dim light at night (dLAN) on the circadian control of metabolism and behavior in rodents, since such an approach can identify the key mechanisms of chronodisruption. Data suggest that the effects of LL are more pronounced compared to dLAN and are directly related to the light level and duration of exposure. Dim LAN reduces nocturnal melatonin levels, similarly to LL, but the consequences on the rhythms of corticosterone and behavioral traits are not uniform and an improved quantification of the disrupted rhythms is needed. Metabolism is under strong circadian control and its disruption can lead to various pathologies. Moreover, metabolism is not only an output, but some metabolites and peripheral signal molecules can feedback on the circadian clockwork and either stabilize or amplify its desynchronization.

scholarly journals The Angiotensin-Melatonin Axis

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Luciana A. Campos ◽  
Jose Cipolla-Neto ◽  
Fernanda G. Amaral ◽  
Lisete C. Michelini ◽  
Michael Bader ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Metabolic Disorders ◽  
Clock Genes ◽  
Renin Angiotensin System ◽  
Angiotensin System ◽  
Beneficial Effects ◽  
Progression Of Disease ◽  
The Central Nervous System ◽  
Peripheral Clocks

Accumulating evidence indicates that various biological and neuroendocrine circadian rhythms may be disrupted in cardiovascular and metabolic disorders. These circadian alterations may contribute to the progression of disease. Our studies direct to an important role of angiotensin II and melatonin in the modulation of circadian rhythms. The brain renin-angiotensin system (RAS) may modulate melatonin synthesis, a hormone with well-established roles in regulating circadian rhythms. Angiotensin production in the central nervous system may not only influence hypertension but also appears to affect the circadian rhythm of blood pressure. Drugs acting on RAS have been proven effective in the treatment of cardiovascular and metabolic disorders including hypertension and diabetes mellitus (DM). On the other hand, since melatonin is capable of ameliorating metabolic abnormalities in DM and insulin resistance, the beneficial effects of RAS blockade could be improved through combined RAS blocker and melatonin therapy. Contemporary research is evidencing the existence of specific clock genes forming central and peripheral clocks governing circadian rhythms. Further research on the interaction between these two neurohormones and the clock genes governing circadian clocks may progress our understanding on the pathophysiology of disease with possible impact on chronotherapeutic strategies.

Spontaneous Recovery of Circadian Organization in Mice Lacking a Core Component of the Molecular Clockwork

2021 ◽  
pp. 074873042110608
Author(s):  
Jonathan P. Riggle ◽  
Kenneth G. Onishi ◽  
Jharnae A. Love ◽  
Dana E. Beach ◽  
Irving Zucker ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Spontaneous Recovery ◽  
Clock Genes ◽  
Feedback Loops ◽  
Constant Darkness ◽  
Core Component ◽  
Period 2 ◽  
Circadian Organization ◽  
Circadian Clock Genes ◽  
Free Running

Circadian rhythms are generated by interlocked transcriptional-translational feedback loops of circadian clock genes and their protein products. Mice homozygous for a functional deletion in the Period-2 gene ( Per2m/m mice) exhibit short free-running circadian periods and eventually lose behavioral circadian rhythmicity in constant darkness (DD). We investigated Per2m/m mice in DD for several months and identified a categorical sex difference in the dependence on Per2 for maintenance of circadian rhythms. Nearly all female Per2m/m mice became circadian arrhythmic in DD, whereas free-running rhythms persisted in 37% of males. Remarkably, with extended testing, Per2m/m mice did not remain arrhythmic in DD, but after varying intervals spontaneously recovered robust, free-running circadian rhythms, with periods shorter than those expressed prior to arrhythmia. Spontaneous recovery was strikingly sex-biased, occurring in 95% of females and 33% of males. Castration in adulthood resulted in male Per2m/m mice exhibiting female-like levels of arrhythmia in DD, but did not affect spontaneous recovery. The circadian pacemaker of many gonad-intact males, but not females, can persist in DD for long intervals without a functional PER2 protein; their circadian clocks may be in an unstable equilibrium, incapable of sustaining persistent coherent circadian organization, resulting in transient cycles of circadian organization and arrhythmia.

scholarly journals Insights into the Role of Circadian Rhythms in Bone Metabolism: A Promising Intervention Target?

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Chao Song ◽  
Jia Wang ◽  
Brett Kim ◽  
Chanyi Lu ◽  
Zheng Zhang ◽  
...  
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Bone Metabolism ◽  
Clock Genes ◽  
Current Knowledge ◽  
Gene Knockout ◽  
Osteoclast Differentiation ◽  
Clock System ◽  
Peripheral Oscillators ◽  
Turnover Markers

Numerous physiological processes of mammals, including bone metabolism, are regulated by the circadian clock system, which consists of a central regulator, the suprachiasmatic nucleus (SCN), and the peripheral oscillators of the BMAL1/CLOCK-PERs/CRYs system. Various bone turnover markers and bone metabolism-regulating hormones such as melatonin and parathyroid hormone (PTH) display diurnal rhythmicity. According to previous research, disruption of the circadian clock due to shift work, sleep restriction, or clock gene knockout is associated with osteoporosis or other abnormal bone metabolism, showing the importance of the circadian clock system for maintaining homeostasis of bone metabolism. Moreover, common causes of osteoporosis, including postmenopausal status and aging, are associated with changes in the circadian clock. In our previous research, we found that agonism of the circadian regulators REV-ERBs inhibits osteoclast differentiation and ameliorates ovariectomy-induced bone loss in mice, suggesting that clock genes may be promising intervention targets for abnormal bone metabolism. Moreover, osteoporosis interventions at different time points can provide varying degrees of bone protection, showing the importance of accounting for circadian rhythms for optimal curative effects in clinical treatment of osteoporosis. In this review, we summarize current knowledge about circadian rhythms and bone metabolism.

Interaction of circadian and stress systems in the regulation of adipose physiology

2014 ◽  
Vol 19 (2) ◽  
Author(s):  
Anthony H. Tsang ◽  
Isa Kolbe ◽  
Julia Seemann ◽  
Henrik Oster
Keyword(s):  
Metabolic Disorders ◽  
Environmental Changes ◽  
Clock Genes ◽  
Feedback Loops ◽  
Endocrine Function ◽  
Stress Hormone ◽  
Shift Workers ◽  
Circadian Oscillators ◽  
Important Mediator ◽  
And Behavior

AbstractEndogenous circadian clocks facilitate the adaptation of physiology and behavior to recurring environmental changes brought about by the Earth’s rotation around its axis. Adipose tissues harbor intrinsic circadian oscillators based on interlocked transcriptional-translational feedback loops built from a set of clock genes that regulate important aspects of lipid metabolism and adipose endocrine function. These adipocyte clocks are reset via neuronal and endocrine pathways originating from a master circadian pacemaker residing in the hypothalamic suprachiasmatic nucleus. One important mediator of circadian output is the stress hormone cortisol, which, at the same time, is one of the major regulators of adipose physiology. In this review we summarize recent findings on the interaction between circadian and stress systems in the regulation of adipose physiology and discuss the implications of this crosstalk for the development of metabolic disorders associated with circadian disruption and/or chronic stress, for example in shift workers.

Artificial light-at-night – a novel lifestyle risk factor for metabolic disorder and cancer morbidity

2017 ◽  
Vol 28 (4) ◽  
Author(s):  
Abed E. Zubidat ◽  
Abraham Haim
Keyword(s):  
Breast Cancer ◽  
Dna Methylation ◽  
Metabolic Disorders ◽  
Clock Genes ◽  
Experimental Studies ◽  
Circadian Disruption ◽  
Cancer Development ◽  
Artificial Light ◽  
Light At Night ◽  
Breast Cancer Development

AbstractBoth obesity and breast cancer are already recognized worldwide as the most common syndromes in our modern society. Currently, there is accumulating evidence from epidemiological and experimental studies suggesting that these syndromes are closely associated with circadian disruption. It has been suggested that melatonin (MLT) and the circadian clock genes both play an important role in the development of these syndromes. However, we still poorly understand the molecular mechanism underlying the association between circadian disruption and the modern health syndromes. One promising candidate is epigenetic modifications of various genes, including clock genes, circadian-related genes, oncogenes, and metabolic genes. DNA methylation is the most prominent epigenetic signaling tool for gene expression regulation induced by environmental exposures, such as artificial light-at-night (ALAN). In this review, we first provide an overview on the molecular feedback loops that generate the circadian regulation and how circadian disruption by ALAN can impose adverse impacts on public health, particularly metabolic disorders and breast cancer development. We then focus on the relation between ALAN-induced circadian disruption and both global DNA methylation and specific loci methylation in relation to obesity and breast cancer morbidities. DNA hypo-methylation and DNA hyper-methylation, are suggested as the most studied epigenetic tools for the activation and silencing of genes that regulate metabolic and monostatic responses. Finally, we discuss the potential clinical and therapeutic roles of MLT suppression and DNA methylation patterns as novel biomarkers for the early detection of metabolic disorders and breast cancer development.

scholarly journals Impacts of home lighting on human health

2021 ◽  
Vol 53 (5) ◽  
pp. 453-475
Author(s):  
C Ticleanu
Keyword(s):  
Energy Efficiency ◽  
Circadian Rhythms ◽  
Human Health ◽  
Electromagnetic Fields ◽  
Good Health ◽  
Sleep Patterns ◽  
Light At Night ◽  
Night Time ◽  
Potential Health ◽  
Areas Of Concern

Typical home lighting practice is mainly centred on visual aspects to enable safe movement between spaces, flexibility in multiuse spaces, a sense of aesthetics and energy efficiency. Whilst lighting impacts on the health of residents have not received similar consideration, this area is gaining increasing interest. This is even more important and actual in the context of the recent pandemic where people have been working or studying from home. A combination of bright daytime light and night-time darkness is essential for circadian entrainment and maintenance of a regular daily sleep–wake cycle, whereas exposure to light at night can negatively impact circadian rhythms and sleep patterns and ultimately lead to potential health problems. Additionally, lighting also has the potential to affect health through associated effects such as flicker, glare, optical hazards or electromagnetic fields. This article discusses the main areas of concern related to home lighting and outlines general recommendations to limit detrimental effects and contribute to good health.

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.

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