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Cancer Biology & Medicine Jan 2023Circadian rhythms are natural rhythms that widely exist in all creatures, and regulate the processes and physiological functions of various biochemical reactions. The... (Review)
Review
Circadian rhythms are natural rhythms that widely exist in all creatures, and regulate the processes and physiological functions of various biochemical reactions. The circadian clock is critical for cancer occurrence and progression. Its function is regulated by metabolic activities, and the expression and transcription of various genes. This review summarizes the composition of the circadian clock; the biological basis for its function; its relationship with, and mechanisms in, cancer; its various functions in different cancers; the effects of anti-tumor treatment; and potential therapeutic targets. Research in this area is expected to advance understanding of circadian locomotor output cycles kaput (CLOCK) and brain and muscle ARNT-like protein 1 (BMAL1) in tumor diseases, and contribute to the development of new anti-tumor treatment strategies.
Topics: Humans; Circadian Clocks; Circadian Rhythm; Neoplasms
PubMed: 36647780
DOI: 10.20892/j.issn.2095-3941.2022.0474 -
Frontiers in Endocrinology 2023Physical activity represents a potent, non-pharmacological intervention delaying the onset of over 40 chronic metabolic and cardiovascular diseases, including type 2... (Review)
Review
Physical activity represents a potent, non-pharmacological intervention delaying the onset of over 40 chronic metabolic and cardiovascular diseases, including type 2 diabetes, coronary heart disease, and reducing all-cause mortality. Acute exercise improves glucose homeostasis, with regular participation in physical activity promoting long-term improvements in insulin sensitivity spanning healthy and disease population groups. At the skeletal muscle level, exercise promotes significant cellular reprogramming of metabolic pathways through the activation of mechano- and metabolic sensors, which coordinate downstream activation of transcription factors, augmenting target gene transcription associated with substrate metabolism and mitochondrial biogenesis. It is well established that frequency, intensity, duration, and modality of exercise play a critical role in the type and magnitude of adaptation; albeit, exercise is increasingly considered a vital lifestyle factor with a critical role in the entrainment of the biological clock. Recent research efforts revealed the time-of-day-dependent impact of exercise on metabolism, adaptation, performance, and subsequent health outcomes. The synchrony between external environmental and behavioural cues with internal molecular circadian clock activity is a crucial regulator of circadian homeostasis in physiology and metabolism, defining distinct metabolic and physiological responses to exercise unique to the time of day. Optimising exercise outcomes following when to exercise would be essential to establishing personalised exercise medicine depending on exercise objectives linked to disease states. We aim to provide an overview of the bimodal impact of exercise timing, i.e. the role of exercise as a time-giver () to improve circadian clock alignment and the underpinning clock control of metabolism and the temporal impact of exercise timing on the metabolic and functional outcomes associated with exercise. We will propose research opportunities that may further our understanding of the metabolic rewiring induced by specific exercise timing.
Topics: Humans; Diabetes Mellitus, Type 2; Homeostasis; Acclimatization; Circadian Clocks; Exercise
PubMed: 36875451
DOI: 10.3389/fendo.2023.987208 -
Nutrients May 2022White adipose tissue (WAT) is a metabolic organ with flexibility to retract and expand based on energy storage and utilization needs, processes that are driven via the... (Review)
Review
White adipose tissue (WAT) is a metabolic organ with flexibility to retract and expand based on energy storage and utilization needs, processes that are driven via the coordination of different cells within adipose tissue. WAT is comprised of mature adipocytes (MA) and cells of the stromal vascular cell fraction (SVF), which include adipose progenitor cells (APCs), adipose endothelial cells (AEC) and infiltrating immune cells. APCs have the ability to proliferate and undergo adipogenesis to form MA, the main constituents of WAT being predominantly composed of white, triglyceride-storing adipocytes with unilocular lipid droplets. While adiposity and adipose tissue health are controlled by diet and aging, the endogenous circadian (24-h) biological clock of the body is highly active in adipose tissue, from adipocyte progenitor cells to mature adipocytes, and may play a unique role in adipose tissue health and function. To some extent, 24-h rhythms in adipose tissue rely on rhythmic energy intake, but individual circadian clock proteins are also thought to be important for healthy fat. Here we discuss how and why the clock might be so important in this metabolic depot, and how temporal and qualitative aspects of energy intake play important roles in maintaining healthy fat throughout aging.
Topics: Adipose Tissue; Adipose Tissue, White; Circadian Clocks; Endothelial Cells; Nutrients
PubMed: 35631227
DOI: 10.3390/nu14102084 -
Biomedicine & Pharmacotherapy =... Jan 2023The circadian clock regulates many key physiological processes such as the sleep-wake cycle, hormone release, cardiovascular health, glucose metabolism and body... (Review)
Review
The circadian clock regulates many key physiological processes such as the sleep-wake cycle, hormone release, cardiovascular health, glucose metabolism and body temperature. Recent evidence has suggested a critical role of the circadian system in controlling bone metabolism. Here we review the connection between bone metabolism and the biological clock, and the roles of these mechanisms in bone loss. We also analyze the regulatory effects of clock-related genes on signaling pathways and transcription factors in osteoblasts and osteoclasts. Additionally, osteocytes and endothelial cells (ECs) regulated by the circadian clock are also discussed in our review. Furthermore, we also summarize the regulation of circadian clock genes by some novel modulators, which provides us with a new insight into a potential strategy to prevent and treat bone diseases such as osteoporosis by targeting circadian genes.
Topics: Circadian Rhythm; Endothelial Cells; Biological Clocks; Transcription Factors; Osteoclasts
PubMed: 36423544
DOI: 10.1016/j.biopha.2022.114019 -
The Psychiatric Clinics of North America Dec 2015There is a growing recognition that the coordinated timing of behavioral, physiologic, and metabolic circadian rhythms is a requirement for a healthy body and mind. In... (Review)
Review
There is a growing recognition that the coordinated timing of behavioral, physiologic, and metabolic circadian rhythms is a requirement for a healthy body and mind. In mammals, the primary circadian oscillator is the hypothalamic suprachiasmatic nucleus (SCN), which is responsible for circadian coordination throughout the organism. Temporal homeostasis is recognized as a complex interplay between rhythmic clock gene expression in brain regions outside the SCN and in peripheral organs. Abnormalities in this intricate circadian orchestration may alter sleep patterns and contribute to the pathophysiology of affective disorders.
Topics: Animals; Circadian Clocks; Circadian Rhythm; Humans; Neural Pathways; Retinal Ganglion Cells; Serotonergic Neurons; Suprachiasmatic Nucleus
PubMed: 26600101
DOI: 10.1016/j.psc.2015.07.003 -
Microbiology and Molecular Biology... Dec 2015Life on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms,... (Review)
Review
Life on earth is subject to daily and predictable fluctuations in light intensity, temperature, and humidity created by rotation of the earth. Circadian rhythms, generated by a circadian clock, control temporal programs of cellular physiology to facilitate adaptation to daily environmental changes. Circadian rhythms are nearly ubiquitous and are found in both prokaryotic and eukaryotic organisms. Here we introduce the molecular mechanism of the circadian clock in the model cyanobacterium Synechococcus elongatus PCC 7942. We review the current understanding of the cyanobacterial clock, emphasizing recent work that has generated a more comprehensive understanding of how the circadian oscillator becomes synchronized with the external environment and how information from the oscillator is transmitted to generate rhythms of biological activity. These results have changed how we think about the clock, shifting away from a linear model to one in which the clock is viewed as an interactive network of multifunctional components that are integrated into the context of the cell in order to pace and reset the oscillator. We conclude with a discussion of how this basic timekeeping mechanism differs in other cyanobacterial species and how information gleaned from work in cyanobacteria can be translated to understanding rhythmic phenomena in other prokaryotic systems.
Topics: Bacterial Proteins; Biological Clocks; Circadian Rhythm; Gene Expression Regulation, Bacterial; Light; Models, Biological; Synechococcus
PubMed: 26335718
DOI: 10.1128/MMBR.00036-15 -
Endocrinology Feb 2021The liver is a "front line" in the homeostatic defenses against variation in nutrient intake. It orchestrates metabolic responses to feeding by secreting factors... (Review)
Review
The liver is a "front line" in the homeostatic defenses against variation in nutrient intake. It orchestrates metabolic responses to feeding by secreting factors essential for maintaining metabolic homeostasis, converting carbohydrates to triglycerides for storage, and releasing lipids packaged as lipoproteins for distribution to other tissues. Between meals, it provides fuel to the body by releasing glucose produced from glucogenic precursors and ketones from fatty acids and ketogenic amino acids. Modern diets enriched in sugars and saturated fats increase lipid accumulation in hepatocytes (nonalcoholic fatty liver disease). If untreated, this can progress to liver inflammation (nonalcoholic steatohepatitis), fibrosis, cirrhosis, and hepatocellular carcinoma. Dysregulation of liver metabolism is also relatively common in modern societies. Increased hepatic glucose production underlies fasting hyperglycemia that defines type 2 diabetes, while increased production of atherogenic, large, triglyceride-rich, very low-density lipoproteins raises the risk of cardiovascular disease. Evidence has accrued of a strong connection between meal timing, the liver clock, and metabolic homeostasis. Metabolic programming of the liver transcriptome and posttranslation modifications of proteins is strongly influenced by the daily rhythms in nutrient intake governed by the circadian clock. Importantly, whereas cell-autonomous clocks have been identified in the liver, the complete circadian programing of the liver transcriptome and posttranslational modifications of essential metabolic proteins is strongly dependent on nutrient flux and circadian signals from outside the liver. The purpose of this review is to provide a basic understanding of liver circadian physiology, drawing attention to recent research on the relationships between circadian biology and liver function.
Topics: Animals; Biological Clocks; Circadian Rhythm; Fasting; Hepatocytes; Humans; Liver; Mice; Non-alcoholic Fatty Liver Disease; Transcriptome
PubMed: 33320193
DOI: 10.1210/endocr/bqaa230 -
Frontiers in Bioscience (Landmark... Sep 2021: Dementia and cognitive loss impact a significant proportion of the global population and present almost insurmountable challenges for treatment since they stem from... (Review)
Review
: Dementia and cognitive loss impact a significant proportion of the global population and present almost insurmountable challenges for treatment since they stem from multifactorial etiologies. Innovative avenues for treatment are highly warranted. : Novel work with biological clock genes that oversee circadian rhythm may meet this critical need by focusing upon the pathways of the mechanistic target of rapamycin (mTOR), the silent mating type information regulation 2 homolog 1 () (SIRT1), mammalian forkhead transcription factors (FoxOs), the growth factor erythropoietin (EPO), and the wingless Wnt pathway. These pathways are complex in nature, intimately associated with autophagy that can maintain circadian rhythm, and have an intricate relationship that can lead to beneficial outcomes that may offer neuroprotection, metabolic homeostasis, and prevention of cognitive loss. However, biological clocks and alterations in circadian rhythm also have the potential to lead to devastating effects involving tumorigenesis in conjunction with pathways involving Wnt that oversee angiogenesis and stem cell proliferation. : Current work with biological clocks and circadian rhythm pathways provide exciting possibilities for the treating dementia and cognitive loss, but also provide powerful arguments to further comprehend the intimate and complex relationship among these pathways to fully potentiate desired clinical outcomes.
Topics: Animals; Biological Clocks; Circadian Clocks; Circadian Rhythm; Dementia; Memory Disorders; TOR Serine-Threonine Kinases
PubMed: 34590471
DOI: 10.52586/4971 -
Current Opinion in Neurobiology Apr 2015Neural oscillations are ubiquitous in olfactory systems of mammals, insects and molluscs. Neurophysiological and computational investigations point to common mechanisms... (Review)
Review
Neural oscillations are ubiquitous in olfactory systems of mammals, insects and molluscs. Neurophysiological and computational investigations point to common mechanisms for gamma or odor associated oscillations across phyla (40-100Hz in mammals, 20-30Hz in insects, 0.5-1.5Hz in molluscs), engaging the reciprocal dendrodendritic synapse between excitatory principle neurons and inhibitory interneurons in the olfactory bulb (OB), antennal lobe (AL), or procerebrum (PrC). Recent studies suggest important mechanisms that may modulate gamma oscillations, including neuromodulators and centrifugal input to the OB and AL. Beta (20Hz) and theta (2-12Hz) oscillations coordinate activity within and across brain regions. Olfactory beta oscillations are associated with odor learning and depend on centrifugal OB input, while theta oscillations are strongly associated with respiration.
Topics: Animals; Biological Clocks; Membrane Potentials; Neurons; Neuropil; Odorants; Olfactory Pathways; Phylogeny; Smell
PubMed: 25460070
DOI: 10.1016/j.conb.2014.10.004 -
The New Phytologist Apr 2021Plant fitness is a measure of the capacity of a plant to survive and reproduce in its particular environment. It is inherently dependent on plant health. Molecular... (Review)
Review
Plant fitness is a measure of the capacity of a plant to survive and reproduce in its particular environment. It is inherently dependent on plant health. Molecular timekeepers like the circadian clock enhance fitness due to their ability to coordinate biochemical and physiological processes with the environment on a daily basis. Central metabolism underlies these events and it is well established that diel metabolite adjustments are intimately and reciprocally associated with the genetically encoded clock. Thus, metabolic pathway activities are time-of-day regulated. Metabolite rhythms are driven by enzymes, a major proportion of which rely on organic coenzymes to facilitate catalysis. The B vitamin complex is the key provider of coenzymes in all organisms. Emerging evidence suggests that B vitamin levels themselves undergo daily oscillations in animals but has not been studied in any depth in plants. Moreover, it is rarely considered that daily rhythmicity in coenzyme levels may dictate enzyme activity levels and therefore metabolite levels. Here we put forward the proposal that B-vitamin-derived coenzyme rhythmicity is intertwined with metabolic and clock derived rhythmicity to achieve a tripartite homeostasis integrated into plant fitness.
Topics: Circadian Clocks; Circadian Rhythm; Coenzymes; Homeostasis; Plants
PubMed: 33264424
DOI: 10.1111/nph.17127