scholarly journals Chronobiology and Metabolism: Is Ketogenic Diet Able to Influence Circadian Rhythm?

2021 ◽  
Vol 15 ◽  
Author(s):  
Elena Gangitano ◽  
Lucio Gnessi ◽  
Andrea Lenzi ◽  
David Ray
Keyword(s):  
Gene Expression ◽  
Circadian Rhythm ◽  
Circadian Clock ◽  
Ketogenic Diet ◽  
Clock Genes ◽  
The Body ◽  
Acid Oxidation ◽  
Metabolic Switch ◽  
Peripheral Tissues ◽  
Central Clock

Circadian rhythms underpin most physiological processes, including energy metabolism. The core circadian clock consists of a transcription-translation negative feedback loop, and is synchronized to light-dark cycles by virtue of light input from the retina, to the central clock in the suprachiasmatic nucleus in the hypothalamus. All cells in the body have circadian oscillators which are entrained to the central clock by neural and humoral signals. In addition to light entrainment of the central clock in the brain, it now emerges that other stimuli can drive circadian clock function in peripheral tissues, the major one being food. This can then drive the liver clock to be misaligned with the central brain clock, a situation of internal misalignment with metabolic disease consequences. Such misalignment is prevalent, with shift workers making up 20% of the working population. The effects of diet composition on the clock are not completely clarified yet. High-fat diet and fasting influence circadian expression of clock genes, inducing phase-advance and phase-delay in animal models. Ketogenic diet (KD) is able to induce a metabolic switch from carbohydrate to fatty acid oxidation, miming a fasting state. In recent years, some animal studies have been conducted to investigate the ability of the KD to modify circadian gene expression, and demonstrated that the KD alters circadian rhythm and induces a rearrangement of metabolic gene expression. These findings may lead to new approaches to obesity and metabolic pathologies treatment.

scholarly journals Circadian Rhythm: Potential Therapeutic Target for Atherosclerosis and Thrombosis

2021 ◽  
Vol 22 (2) ◽  
pp. 676
Author(s):  
Andy W. C. Man ◽  
Huige Li ◽  
Ning Xia
Keyword(s):  
Circadian Rhythm ◽  
Cardiovascular Diseases ◽  
Circadian Rhythms ◽  
Circadian Clock ◽  
Therapeutic Target ◽  
Environmental Changes ◽  
Clock Genes ◽  
Vascular System ◽  
Peripheral Tissues ◽  
Inflammatory Processes

Every organism has an intrinsic biological rhythm that orchestrates biological processes in adjusting to daily environmental changes. Circadian rhythms are maintained by networks of molecular clocks throughout the core and peripheral tissues, including immune cells, blood vessels, and perivascular adipose tissues. Recent findings have suggested strong correlations between the circadian clock and cardiovascular diseases. Desynchronization between the circadian rhythm and body metabolism contributes to the development of cardiovascular diseases including arteriosclerosis and thrombosis. Circadian rhythms are involved in controlling inflammatory processes and metabolisms, which can influence the pathology of arteriosclerosis and thrombosis. Circadian clock genes are critical in maintaining the robust relationship between diurnal variation and the cardiovascular system. The circadian machinery in the vascular system may be a novel therapeutic target for the prevention and treatment of cardiovascular diseases. The research on circadian rhythms in cardiovascular diseases is still progressing. In this review, we briefly summarize recent studies on circadian rhythms and cardiovascular homeostasis, focusing on the circadian control of inflammatory processes and metabolisms. Based on the recent findings, we discuss the potential target molecules for future therapeutic strategies against cardiovascular diseases by targeting the circadian clock.

Circadian Rhythm, Clock Genes, and Hypertension: Recent Advances in Hypertension

Hypertension ◽  
2021 ◽  
Author(s):  
Hannah M. Costello ◽  
Michelle L. Gumz
Keyword(s):  
Circadian Rhythm ◽  
Circadian Clock ◽  
Clock Genes ◽  
Adverse Outcomes ◽  
The Body ◽  
Perivascular Adipose Tissue ◽  
Area Of Interest ◽  
Recent Advances ◽  
Increased Risk ◽  
Peripheral Clocks

Accumulating evidence suggests that the molecular circadian clock is crucial in blood pressure (BP) control. Circadian rhythms are controlled by the central clock, which resides in the suprachiasmatic nucleus of the hypothalamus and peripheral clocks throughout the body. Both light and food cues entrain these clocks but whether these cues are important for the circadian rhythm of BP is a growing area of interest. The peripheral clocks in the smooth muscle, perivascular adipose tissue, liver, adrenal gland, and kidney have been recently implicated in the regulation of BP rhythm. Dysregulation of the circadian rhythm of BP is associated with adverse cardiorenal outcomes and increased risk of cardiovascular mortality. In this review, we summarize the most recent advances in peripheral clocks as BP regulators, highlight the adverse outcomes of disrupted circadian BP rhythm in hypertension, and provide insight into potential future work in areas exploring the circadian clock in BP control and chronotherapy. A better understanding of peripheral clock function in regulating the circadian rhythm of BP will help pave the way for targeted therapeutics in the treatment of circadian BP dysregulation and hypertension.

The circadian clock and metabolism

2010 ◽  
Vol 120 (2) ◽  
pp. 65-72 ◽  
Author(s):  
Oren Froy
Keyword(s):  
Circadian Clock ◽  
Clock Genes ◽  
The Body ◽  
Suprachiasmatic Nuclei ◽  
Peripheral Tissues ◽  
Environmental Light ◽  
Activity Of Enzymes ◽  
Transcription Activators ◽  
The Relationship ◽  
Daily Changes

Mammals have developed an endogenous circadian clock located in the SCN (suprachiasmatic nuclei) of the anterior hypothalamus that responds to the environmental light–dark cycle. Human homoeostatic systems have adapted to daily changes in a way that the body anticipates the sleep and activity periods. Similar clocks have been found in peripheral tissues, such as the liver, intestine and adipose tissue. Recently it has been found that the circadian clock regulates cellular and physiological functions in addition to the expression and/or activity of enzymes and hormones involved in metabolism. In turn, key metabolic enzymes and transcription activators interact with and affect the core clock mechanism. Animals with mutations in clock genes that disrupt cellular rhythmicity have provided evidence to the relationship between the circadian clock and metabolic homoeostasis. The present review will summarize recent findings concerning the relationship between metabolism and circadian rhythms.

scholarly journals Homologues of key circadian clock genes present in Verticillium dahliae do not direct circadian programs of development or mRNA abundance

2019 ◽  
Author(s):  
Emma Cascant-Lopez ◽  
Susan K. Crosthwaite ◽  
Louise J. Johnson ◽  
Richard J. Harrison
Keyword(s):  
Gene Expression ◽  
Circadian Clock ◽  
Verticillium Dahliae ◽  
Plant Pathogen ◽  
Environmental Conditions ◽  
Clock Genes ◽  
Circadian Clocks ◽  
Constant Darkness ◽  
Clock Proteins ◽  
Central Clock

AbstractMany organisms harbour circadian clocks that promote their adaptation to the rhythmic environment. While a broad knowledge of the molecular mechanism of circadian clocks has been gained through the fungal model Neurospora crassa, little is known about circadian clocks in other fungi. N. crassa belongs to the same class as many important plant pathogens including the vascular wilt fungus Verticillium dahliae. We identified homologues of N. crassa clock proteins in V. dahliae, which showed high conservation in key protein domains. However, no evidence for an endogenous, free-running and entrainable rhythm was observed in the daily formation of conidia and microsclerotia. In N. crassa the frequency (frq) gene encodes a central clock protein expressed rhythmically and in response to light. In contrast, expression of Vdfrq is not light-regulated. Temporal gene expression profiling over 48 hours in constant darkness and temperature revealed no circadian expression of key clock genes. Furthermore, RNA-seq over a 24 h time-course revealed no robust oscillations of RNA in constant darkness. Comparison of gene expression between wild-type V. dahliae and a ΔVdfrq mutant showed that genes involved in metabolism, transport and redox processes are mis-regulated in the absence of Vdfrq. In addition, VdΔfrq mutants display growth defects and reduced pathogenicity in a strain dependent manner. Our data indicate that if a circadian clock exists in Verticillium, it is based on alternative mechanisms such as post-transcriptional interactions of VdFRQ and the WC proteins or the components of a FRQ-less oscillator. Alternatively, it could be that whilst the original functions of the clock proteins have been maintained, in this species the interactions that generate rhythmicity have been lost or are only triggered when specific environmental conditions are met. The presence of conserved clock genes in genomes should not be taken as definitive evidence of circadian function.Author summaryCircadian clocks are used by organisms to orchestrate the activity of cellular processes such that they occur at an optimal time of day. Research carried out in the filamentous fungus Neurospora crassa has revealed a huge amount of information about the components its circadian clock, its interactions with the environment and how it drives cellular biochemistry and physiology. Although homologues of the Neurospora clock genes are present in a number of fungi, functional clocks have been demonstrated in a just a handful. Importantly, a link between the circadian clock of the plant pathogen Botrytis cinerea and virulence has recently been reported. We report that another significant plant pathogen, Verticillium dahliae, contains well-conserved homologues of all key clock genes. We find that diurnal development of conidia and microsclerotia is not influenced by a circadian clock. Furthermore, in a constant environment we find no evidence of rhythmic transcript accumulation. However, deletion of the central clock component results in altered growth and reduced virulence. This led us to question the role of clock genes in Verticillium. We are forced to consider that in this species the interactions that generate rhythmicity have been lost, are generated purely via post-transcriptional modification of clock proteins, are only triggered when specific environmental conditions are met or never evolved.

scholarly journals Transcriptomal dissection of soybean circadian rhythmicity in two geographically, phenotypically and genetically distinct cultivars

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Yanlei Yue ◽  
Ze Jiang ◽  
Enoch Sapey ◽  
Tingting Wu ◽  
Shi Sun ◽  
...  
Keyword(s):  
Gene Expression ◽  
Circadian Clock ◽  
Chromosome Structure ◽  
Clock Genes ◽  
Expression Profiles ◽  
Circadian Rhythmicity ◽  
Rna Seq ◽  
Night Time ◽  
Time Points ◽  
Circadian Clock Genes

Abstract Background In soybean, some circadian clock genes have been identified as loci for maturity traits. However, the effects of these genes on soybean circadian rhythmicity and their impacts on maturity are unclear. Results We used two geographically, phenotypically and genetically distinct cultivars, conventional juvenile Zhonghuang 24 (with functional J/GmELF3a, a homolog of the circadian clock indispensable component EARLY FLOWERING 3) and long juvenile Huaxia 3 (with dysfunctional j/Gmelf3a) to dissect the soybean circadian clock with time-series transcriptomal RNA-Seq analysis of unifoliate leaves on a day scale. The results showed that several known circadian clock components, including RVE1, GI, LUX and TOC1, phase differently in soybean than in Arabidopsis, demonstrating that the soybean circadian clock is obviously different from the canonical model in Arabidopsis. In contrast to the observation that ELF3 dysfunction results in clock arrhythmia in Arabidopsis, the circadian clock is conserved in soybean regardless of the functional status of J/GmELF3a. Soybean exhibits a circadian rhythmicity in both gene expression and alternative splicing. Genes can be grouped into six clusters, C1-C6, with different expression profiles. Many more genes are grouped into the night clusters (C4-C6) than in the day cluster (C2), showing that night is essential for gene expression and regulation. Moreover, soybean chromosomes are activated with a circadian rhythmicity, indicating that high-order chromosome structure might impact circadian rhythmicity. Interestingly, night time points were clustered in one group, while day time points were separated into two groups, morning and afternoon, demonstrating that morning and afternoon are representative of different environments for soybean growth and development. However, no genes were consistently differentially expressed over different time-points, indicating that it is necessary to perform a circadian rhythmicity analysis to more thoroughly dissect the function of a gene. Moreover, the analysis of the circadian rhythmicity of the GmFT family showed that GmELF3a might phase- and amplitude-modulate the GmFT family to regulate the juvenility and maturity traits of soybean. Conclusions These results and the resultant RNA-seq data should be helpful in understanding the soybean circadian clock and elucidating the connection between the circadian clock and soybean maturity.

scholarly journals Daily rhythms in gene expression of the human parasite Schistosoma mansoni

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Kate A. Rawlinson ◽  
Adam J. Reid ◽  
Zhigang Lu ◽  
Patrick Driguez ◽  
Anna Wawer ◽  
...  
Keyword(s):  
Gene Expression ◽  
Schistosoma Mansoni ◽  
Circadian Clock ◽  
Drug Targets ◽  
Clock Genes ◽  
Biological Rhythms ◽  
Active Phase ◽  
Egg Laying ◽  
Daily Rhythms ◽  
Metazoan Parasites

Abstract Background The consequences of the earth’s daily rotation have led to 24-h biological rhythms in most organisms. Even some parasites are known to have daily rhythms, which, when in synchrony with host rhythms, can optimise their fitness. Understanding these rhythms may enable the development of control strategies that take advantage of rhythmic vulnerabilities. Recent work on protozoan parasites has revealed 24-h rhythms in gene expression, drug sensitivity and the presence of an intrinsic circadian clock; however, similar studies on metazoan parasites are lacking. To address this, we investigated if a metazoan parasite has daily molecular oscillations, whether they reveal how these longer-lived organisms can survive host daily cycles over a lifespan of many years and if animal circadian clock genes are present and rhythmic. We addressed these questions using the human blood fluke Schistosoma mansoni that lives in the vasculature for decades and causes the tropical disease schistosomiasis. Results Using round-the-clock transcriptomics of male and female adult worms collected from experimentally infected mice, we discovered that ~ 2% of its genes followed a daily pattern of expression. Rhythmic processes included a stress response during the host’s active phase and a ‘peak in metabolic activity’ during the host’s resting phase. Transcriptional profiles in the female reproductive system were mirrored by daily patterns in egg laying (eggs are the main drivers of the host pathology). Genes cycling with the highest amplitudes include predicted drug targets and a vaccine candidate. These 24-h rhythms may be driven by host rhythms and/or generated by a circadian clock; however, orthologs of core clock genes are missing and secondary clock genes show no 24-h rhythmicity. Conclusions There are daily rhythms in the transcriptomes of adult S. mansoni, but they appear less pronounced than in other organisms. The rhythms reveal temporally compartmentalised internal processes and host interactions relevant to within-host survival and between-host transmission. Our findings suggest that if these daily rhythms are generated by an intrinsic circadian clock then the oscillatory mechanism must be distinct from that in other animals. We have shown which transcripts oscillate at this temporal scale and this will benefit the development and delivery of treatments against schistosomiasis.

scholarly journals Modeling and analysis of the impacts of jet lag on circadian rhythm and its role in tumor growth

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4877 ◽  
Author(s):  
Azka Hassan ◽  
Jamil Ahmad ◽  
Hufsah Ashraf ◽  
Amjad Ali
Keyword(s):  
Circadian Rhythms ◽  
Circadian Clock ◽  
Clock Genes ◽  
Damage Control ◽  
Vital Role ◽  
Biochemical Networks ◽  
Jet Lag ◽  
Peripheral Tissues ◽  
Modeling And Analysis ◽  
Circadian Clock Proteins

Circadian rhythms maintain a 24 h oscillation pattern in metabolic, physiological and behavioral processes in all living organisms. Circadian rhythms are organized as biochemical networks located in hypothalamus and peripheral tissues. Rhythmicity in the expression of circadian clock genes plays a vital role in regulating the process of cell division and DNA damage control. The oncogenic protein, MYC and the tumor suppressor, p53 are directly influenced by the circadian clock. Jet lag and altered sleep/wake schedules prominently affect the expression of molecular clock genes. This study is focused on developing a Petri net model to analyze the impacts of long term jet lag on the circadian clock and its probable role in tumor progression. The results depict that jet lag disrupts the normal rhythmic behavior and expression of the circadian clock proteins. This disruption leads to persistent expression of MYC and suppressed expression of p53. Thus, it is inferred that jet lag altered circadian clock negatively affects the expressions of cell cycle regulatory genes and contribute in uncontrolled proliferation of tumor cells.

The Circadian Clock inArabidopsisRoots Is a Simplified Slave Version of the Clock in Shoots

Science ◽  
2008 ◽  
Vol 322 (5909) ◽  
pp. 1832-1835 ◽  
Author(s):  
Allan B. James ◽  
José A. Monreal ◽  
Gillian A. Nimmo ◽  
Ciarán L. Kelly ◽  
Pawel Herzyk ◽  
...  
Keyword(s):  
Gene Expression ◽  
Transcription Factors ◽  
Circadian Clock ◽  
Clock Genes ◽  
Plant Cells ◽  
Feedback Loops ◽  
Circadian Oscillator ◽  
Inhibit Gene Expression ◽  
Organ Specific ◽  
Plant Clock

The circadian oscillator in eukaryotes consists of several interlocking feedback loops through which the expression of clock genes is controlled. It is generally assumed that all plant cells contain essentially identical and cell-autonomous multiloop clocks. Here, we show that the circadian clock in the roots of matureArabidopsisplants differs markedly from that in the shoots and that the root clock is synchronized by a photosynthesis-related signal from the shoot. Two of the feedback loops of the plant circadian clock are disengaged in roots, because two key clock components, the transcription factors CCA1 and LHY, are able to inhibit gene expression in shoots but not in roots. Thus, the plant clock is organ-specific but not organ-autonomous.

scholarly journals MECHANISMS IN ENDOCRINOLOGY: A sense of time of the glucocorticoid circadian clock: from the ontogeny to the diagnosis of Cushing’s syndrome

2018 ◽  
Vol 179 (1) ◽  
pp. R1-R18 ◽  
Author(s):  
Ayrton Custodio Moreira ◽  
Sonir Rauber Antonini ◽  
Margaret de Castro
Keyword(s):  
Circadian Rhythm ◽  
Circadian Clock ◽  
Clock Genes ◽  
Circadian Variation ◽  
Circadian System ◽  
Feedback Loops ◽  
Adrenal Axis ◽  
Sense Of Time ◽  
Pituitary Adrenal Axis ◽  
Hierarchical Manner

The circadian rhythm of glucocorticoids has long been recognised within the last 75 years. Since the beginning, researchers have sought to identify basic mechanisms underlying the origin and emergence of the corticosteroid circadian rhythmicity among mammals. Accordingly, Young, Hall and Rosbash, laureates of the 2017 Nobel Prize in Physiology or Medicine, as well as Takahashi’s group among others, have characterised the molecular cogwheels of the circadian system, describing interlocking transcription/translation feedback loops essential for normal circadian rhythms. Plasma glucocorticoid circadian variation depends on the expression of intrinsic clock genes within the anatomic components of the hypothalamic–pituitary–adrenal axis, which are organised in a hierarchical manner. This review presents a general overview of the glucocorticoid circadian clock mechanisms, highlighting the ontogeny of the pituitary–adrenal axis diurnal rhythmicity as well as the involvement of circadian rhythm abnormalities in the physiopathology and diagnosis of Cushing’s disease.

scholarly journals “Gut Microbiota-Circadian Clock Axis” in Deciphering the Mechanism Linking Early-Life Nutritional Environment and Abnormal Glucose Metabolism

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Liyuan Zhou ◽  
Lin Kang ◽  
Xinhua Xiao ◽  
Lijing Jia ◽  
Qian Zhang ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Circadian Rhythm ◽  
Gut Microbiota ◽  
Circadian Clock ◽  
Early Life ◽  
Metabolic Diseases ◽  
Clock Genes ◽  
Early Stage ◽  
Adult Life ◽  
Metabolic Memory

The prevalence of diabetes mellitus (DM) has been increasing dramatically worldwide, but the pathogenesis is still unknown. A growing amount of evidence suggests that an abnormal developmental environment in early life increases the risk of developing metabolic diseases in adult life, which is referred to as the “metabolic memory” and the Developmental Origins of Health and Disease (DOHaD) hypothesis. The mechanism of “metabolic memory” has become a hot topic in the field of DM worldwide and could be a key to understanding the pathogenesis of DM. In recent years, several large cohort studies have shown that shift workers have a higher risk of developing type 2 diabetes mellitus (T2DM) and worse control of blood glucose levels. Furthermore, a maternal high-fat diet could lead to metabolic disorders and abnormal expression of clock genes and clock-controlled genes in offspring. Thus, disorders of circadian rhythm might play a pivotal role in glucose metabolic disturbances, especially in terms of early adverse nutritional environments and the development of metabolic diseases in later life. In addition, as a peripheral clock, the gut microbiota has its own circadian rhythm that fluctuates with periodic feeding and has been widely recognized for its significant role in metabolism. In light of the important roles of the gut microbiota and circadian clock in metabolic health and their interconnected regulatory relationship, we propose that the “gut microbiota-circadian clock axis” might be a novel and crucial mechanism to decipher “metabolic memory.” The “gut microbiota-circadian clock axis” is expected to facilitate the future development of a novel target for the prevention and intervention of diabetes during the early stage of life.

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