The Interconnection between Hepatic Insulin Resistance and Metabolic Dysfunction-Associated Steatotic Liver Disease-The Transition from an Adipocentric to Liver-Centric Approach

The central mechanism involved in the pathogenesis of MAFLD is insulin resistance with hyperinsulinemia, which stimulates triglyceride synthesis and accumulation in the liver. On the other side, triglyceride and free fatty acid accumulation in hepatocytes promotes insulin resistance via oxidative stress, endoplasmic reticulum stress, lipotoxicity, and the increased secretion of hepatokines. Cytokines and adipokines cause insulin resistance, thus promoting lipolysis in adipose tissue and ectopic fat deposition in the muscles and liver. Free fatty acids along with cytokines and adipokines contribute to insulin resistance in the liver via the activation of numerous signaling pathways. The secretion of hepatokines, hormone-like proteins, primarily by hepatocytes is disturbed and impairs signaling pathways, causing metabolic dysregulation in the liver. ER stress and unfolded protein response play significant roles in insulin resistance aggravation through the activation of apoptosis, inflammatory response, and insulin signaling impairment mediated via IRE1/PERK/ATF6 signaling pathways and the upregulation of SREBP 1c. Circadian rhythm derangement and biological clock desynchronization are related to metabolic disorders, insulin resistance, and NAFLD, suggesting clock genes as a potential target for new therapeutic strategies. This review aims to summarize the mechanisms of hepatic insulin resistance involved in NAFLD development and progression.

Time-restricted feeding affects the fecal microbiome metabolome and its diurnal oscillations in lung cancer mice

The homeostasis of the gut microbiota and circadian rhythm is critical to host health, and both are inextricably intertwined with lung cancer. Although time-restricted feeding (TRF) can maintain circadian synchronization and improve metabolic disorders, the effects of TRF on the fecal microbiome, metabolome and their diurnal oscillations in lung cancer have not been discussed. We performed 16S rRNA sequencing and untargeted metabonomic sequencing of the feces prepared from models of tumor-bearing BALB/c nude mice and urethane-induced lung cancer. We demonstrated for the first time that TRF significantly delayed the growth of lung tumors. Moreover, TRF altered the abundances of the fecal microbiome, metabolome and circadian clocks, as well as their rhythmicity, in lung cancer models of tumor-bearing BALB/c nude mice and/or urethane-induced lung cancer C57BL/6J mice. The results of fecal microbiota transplantation proved that the antitumor effects of TRF occur by regulating the fecal microbiota. Notably, Lactobacillus and Bacillus were increased upon TRF and were correlated with most differential metabolites. Pathway enrichment analysis of metabolites revealed that TRF mainly affected immune and inflammatory processes, which might further explain how TRF exerted its anticancer benefits. These findings underscore the possibility that the fecal microbiome/metabolome regulates lung cancer following a TRF paradigm.

Tick tock, the cartilage clock

Osteoarthritis (OA) is the most common age-related joint disease, affecting articular cartilage and other joint structures, causing severe pain and disability. Due to a limited understanding of the underlying disease pathogenesis, there are currently no disease-modifying drugs for OA. Circadian rhythms are generated by cell-intrinsic timekeeping mechanisms which are known to dampen during ageing, increasing disease risks. In this review, we focus on one emerging area of chondrocyte biology, the circadian clocks. We first provide a historical perspective of circadian clock discoveries and the molecular underpinnings. We will then focus on the expression and functions of circadian clocks in articular cartilage, including their rhythmic target genes and pathways, links to ageing, tissue degeneration, and OA, as well as tissue niche-specific entrainment pathways. Further research into cartilage clocks and ageing may have broader implications in the understanding of OA pathogenesis, the standardization of biomarker detection, and the development of novel therapeutic routes for the prevention and management of OA and other musculoskeletal diseases.

Circadian regulation of liver function: from molecular mechanisms to disease pathophysiology

A wide variety of liver functions are regulated daily by the liver circadian clock and via systemic circadian control by other organs and cells within the gastrointestinal tract as well as the microbiome and immune cells. Disruption of the circadian system, as occurs during jetlag, shift work or an unhealthy lifestyle, is implicated in several liver-related pathologies, ranging from metabolic diseases such as obesity, type 2 diabetes mellitus and nonalcoholic fatty liver disease to liver malignancies such as hepatocellular carcinoma. In this Review, we cover the molecular, cellular and organismal aspects of various liver pathologies from a circadian viewpoint, and in particular how circadian dysregulation has a role in the development and progression of these diseases. Finally, we discuss therapeutic and lifestyle interventions that carry health benefits through support of a functional circadian clock that acts in synchrony with the environment.

Identification of key circadian rhythm genes in skin aging based on bioinformatics and machine learning

Skin aging is often accompanied by disruption of circadian rhythm and abnormal expression of circadian rhythm-related genes. In this study, we downloaded skin aging expression datasets from the GEO database and utilized bioinformatics and machine learning methods to explore circadian rhythm genes and pathways involved in skin aging, revealing the pathological and molecular mechanisms of skin aging. Results showed that 39 circadian rhythm-related genes (CRGs) were identified in skin aging, and these CRGs were enriched in signaling pathways such as glucagon signaling pathway, insulin resistance, thyroid hormone signaling pathway, and adipocytokine signaling pathway. Three key skin aging-related CRGs, SIRT1, ARNTL, and ATF4, were identified based on machine learning. Additionally, we found that skin aging was associated with infiltration of immune cells including NK cells activated, Macrophages M1, Mast cells resting, T cells CD4 memory activated, and Macrophages M2, and the expression of the three key skin aging-related CRGs was correlated with these immune cells. Finally, SIRT1, ARNTL, and ATF4 were all down-regulated in skin aging and had a good ability to distinguish young skin tissue from aging skin tissue. In conclusion, three key CRGs, including SIRT1, ARNTL, and ATF4, which are closely related to skin aging, were obtained based on bioinformatics and machine learning technology screening. These three key CRGs were potential risk genes for skin aging and also associated with changes in the immune microenvironment in skin aging. The language used in this paragraph follows the guidelines for scientific writing specified by SCI, making it clear and concise.

The Mediation Role of Sleep Disturbances between Vitamin D and Depressive Symptoms: A Cross-Sectional Study

Depression and sleep disturbances are highly prevalent health problems that have been suggested to be associated with vitamin D deficiency. This study investigated whether sleep disturbances affect the association between vitamin D and depressive symptoms. A total of 425 patients with depression were included in this study. Spearman correlation coefficients were chosen to assess the relation between vitamin D concentrations and depressive symptomatology (according to the PHQ-9 and HAMD-17 scores). The GLM Mediation Model in the Medmod module for data analysis in Jamovi 2.2.5 was used to analyze the mediation models for sleep disturbances. Vitamin D concentrations were significantly correlated with PHQ-9 and HAMD-17 scale scores. In addition, item 3 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of PHQ-9, and item 4 was suggested to have a mediating effect between vitamin D and depressive symptoms in the mediating model of HAMD-17. Sleep disturbances (especially difficulty falling asleep) are mediators between vitamin D and depressive symptoms, suggesting that increasing vitamin D levels at the right time to regulate sleep disturbances may improve depression symptoms, yet further research is necessary.

Sleep Pathologies and Eating Disorders: A Crossroad for Neurology, Psychiatry and Nutrition

The intricate connection between eating behaviors and sleep habits is often overlooked in clinical practice, despite their profound interdependence. Sleep plays a key role in modulating psychological, hormonal and metabolic balance and exerting an influence on food choices. Conversely, various eating disorders may affect sleep continuity, sometimes promoting the development of sleep pathologies. Neurologists, nutritionists and psychiatrists tend to focus on these issues separately, resulting in a failure to recognize the full extent of the clinical conditions. This detrimental separation can lead to underestimation, misdiagnosis and inappropriate therapeutic interventions. In this review, we aim to provide a comprehensive understanding of the tangled relationship between sleep, sleep pathologies and eating disorders, by incorporating the perspective of sleep experts, psychologists and psychiatrists. Our goal is to identify a practical crossroad integrating the expertise of all the involved specialists.

U.S. Adolescent Rest-Activity patterns: insights from functional principal component analysis (NHANES 2011-2014)

BACKGROUND

Suboptimal rest-activity patterns in adolescence are associated with worse health outcomes in adulthood. Understanding sociodemographic factors associated with rest-activity rhythms may help identify subgroups who may benefit from interventions. This study aimed to investigate the association of rest-activity rhythm with demographic and socioeconomic characteristics in adolescents.

METHODS

Using cross-sectional data from the nationally representative National Health and Nutrition Examination Survey (NHANES) 2011-2014 adolescents (N = 1814), this study derived rest-activity profiles from 7-day 24-hour accelerometer data using functional principal component analysis. Multiple linear regression was used to assess the association between participant characteristics and rest-activity profiles. Weekday and weekend specific analyses were performed in addition to the overall analysis.

RESULTS

Four rest-activity rhythm profiles were identified, which explained a total of 82.7% of variance in the study sample, including (1) High amplitude profile; (2) Early activity window profile; (3) Early activity peak profile; and (4) Prolonged activity/reduced rest window profile. The rest-activity profiles were associated with subgroups of age, sex, race/ethnicity, and household income. On average, older age was associated with a lower value for the high amplitude and early activity window profiles, but a higher value for the early activity peak and prolonged activity/reduced rest window profiles. Compared to boys, girls had a higher value for the prolonged activity/reduced rest window profiles. When compared to Non-Hispanic White adolescents, Asian showed a lower value for the high amplitude profile, Mexican American group showed a higher value for the early activity window profile, and the Non-Hispanic Black group showed a higher value for the prolonged activity/reduced rest window profiles. Adolescents reported the lowest household income had the lowest average value for the early activity window profile.

CONCLUSIONS

This study characterized main rest-activity profiles among the US adolescents, and demonstrated that demographic and socioeconomic status factors may shape rest-activity behaviors in this population.

Enhanced precision of circadian rhythm by output system

Circadian rhythms are biological rhythms with a period of approximately 24 h that persist even under constant conditions without daily environmental cues. The molecular circadian clock machinery generates physiological rhythms, which can be transmitted into the downstream output system. Owing to the stochastic nature of the biochemical reactions and the extracellular environment, the oscillation period of circadian rhythms exhibited by individual organisms or cells is not constant on a daily basis with variations as high as 10%, as reflected by the coefficient of variation. Although the fluctuations in the circadian rhythm are measured through a reporter system such as bioluminescence or fluorescence, which is an example of output systems, experimentally confirming whether the fluctuations found in the reporter system are the same as those in the circadian clock is challenging. This study investigated a coupled system of a circadian clock and its output system numerically and analytically, and then compared the fluctuations in the oscillation period of the two systems. We found that the amount of fluctuations in the output system is smaller than that in the circadian clock, assuming the degradation rate of the molecules responsible for the output system is a typical value for protein degradation. The results indicate that the output system can improve the accuracy of the circadian rhythm without the need for any denoising processes.

Mechanisms and physiological function of daily haemoglobin oxidation rhythms in red blood cells

Cellular circadian rhythms confer temporal organisation upon physiology that is fundamental to human health. Rhythms are present in red blood cells (RBCs), the most abundant cell type in the body, but their physiological function is poorly understood. Here, we present a novel biochemical assay for haemoglobin (Hb) oxidation status which relies on a redox-sensitive covalent haem-Hb linkage that forms during SDS-mediated cell lysis. Formation of this linkage is lowest when ferrous Hb is oxidised, in the form of ferric metHb. Daily haemoglobin oxidation rhythms are observed in mouse and human RBCs cultured in vitro, or taken from humans in vivo, and are unaffected by mutations that affect circadian rhythms in nucleated cells. These rhythms correlate with daily rhythms in core body temperature, with temperature lowest when metHb levels are highest. Raising metHb levels with dietary sodium nitrite can further decrease daytime core body temperature in mice via nitric oxide (NO) signalling. These results extend our molecular understanding of RBC circadian rhythms and suggest they contribute to the regulation of body temperature.

The unfixed light pattern contributes to depressive-like behaviors in male mice

Light pollution is now associated with an increased incidence of mental disorders in humans, and the unfixed light pattern (ULP) is a common light pollution that occurs in such as rotating shift work. However, how much contribution the ULP has to depression and its potential mechanism are yet unknown. Our study aimed to investigate the effect of the ULP on depressive-like behaviors in mice and to explore the links to the circadian-orexinergic system. Male C57BL/6 J mice were exposed to the ULP by subjecting them to an alternating light pattern every 6 days for 54 days. The tail suspension test (TST) and forced swimming test (FST) were conducted to assess depressive-like behaviors. The rhythm of locomotor activity and the circadian expression of cFOS in the suprachiasmatic nucleus (SCN), clock genes in the liver, and corticosterone (CORT) in serum were detected to observe changes in the circadian system. The circadian expression of orexin-A (OX-A) in the lateral hypothalamus area (LHA) and dorsal raphe nucleus (DRN) and serotonin (5-HT) in the DRN were measured to determine alterations in the orexinergic system. The results showed that mice exposed to the ULP exhibited increased immobility time in the TST and FST. The ULP significantly disrupted the circadian rhythm of locomotor activity, clock genes in the liver, and CORT in the serum. Importantly, when exposed to the ULP, cFOS expression in the SCN showed decreased amplitude. Its projection area, the LHA, had a lower mesor of OX-A expression. OX-A projection to the DRN and 5-HT expression in the DRN were reduced in mesor. Our research suggests that the ULP contributes to depressive-like behaviors in mice, which might be related to the reduced amplitude of circadian oscillation in the SCN and hypoactivity of the orexinergic system. These findings may provide novel insights into rotating shift work-related depression.

Time-restricted eating for chronodisruption-related chronic diseases

The circadian timing system enables organisms to adapt their physiology and behavior to the cyclic environmental changes including light-dark cycle or food availability. Misalignment between the endogenous circadian rhythms and external cues is known as chronodisruption and is closely associated with the development of metabolic and gastrointestinal disorders, cardiovascular diseases, and cancer. Time-restricted eating (TRE, in human) is an emerging dietary approach for weight management. Recent studies have shown that TRE or time-restricted feeding (TRF, when referring to animals) has several beneficial health effects, which, however, are not limited to weight management. This review summarizes the effects of TRE/TRF on regulating energy metabolism, gut microbiota and homeostasis, development of cardiovascular diseases and cancer. Furthermore, we will address the role of circadian clocks in TRE/TRF and propose ways to optimize TRE as a dietary strategy to obtain maximal health benefits.

Rescue of Comorbid Behavioral and Metabolic Phenotypes of Arrhythmic Mice by Restoring Circadian Cry1/2 Expression in the Suprachiasmatic Nucleus

Background

Psychiatric and metabolic disorders occur disproportionately often comorbidly, which poses particular hurdles for patients and therapists. However, the mechanisms that promote such comorbidities are largely unknown and therefore cannot yet be therapeutically targeted for the simultaneous treatment of both conditions. Because circadian clocks regulate most physiological processes and their disruption is a risk factor for both psychiatric and metabolic disorders, they may be considered as a potential mechanism for the development of comorbidities and a therapeutic target. In the current study, we investigated the latter assumption in Cry1/2-/- mice, which exhibit substantially disrupted endogenous circadian rhythms and marked metabolic and behavioral deficits.

Methods

By targeted virus-induced restoration of circadian rhythms in their suprachiasmatic nucleus, we can restore behavioral as well as several metabolic processes of these animals to near-normal circadian rhythmicity.

Results

Importantly, by rescuing suprachiasmatic nucleus rhythms, several of their anxiety-like behavioral as well as diabetes- and energy homeostasis-related deficits were significantly improved. Interestingly, however, this did not affect all deficits typical of Cry1/2-/- mice; for example, restlessness and body weight remained unaffected.

Conclusions

Taken together, the results of this study demonstrate, on the one hand, that restoration of disturbed circadian rhythms can be used to simultaneously treat psychiatric and metabolic deficits. On the other hand, the results also allow us to distinguish processes that depend more on local canonical clocks from those that depend more on suprachiasmatic nucleus rhythms.

Assessment of Corneal Biomechanical Properties using Scheimpflug Camera-Based Imaging in Night Shift Medical Staff

Purpose

To evaluate the effect of night shifts on the biomechanical properties of the cornea using Scheimpflug camera-based imaging (Corvis and Pentacam).

Methods

Thirty-four participants from the medical staff who had at least six night shifts per month as a case group and fifty-two participants as a control group participated in the study. The biomechanical characteristics of the cornea using the Corvis device and the topographical characteristics of the cornea using the Pentacam device were investigated in the participants.

Results

The main indices of corneal biomechanics including Corvis Biomechanical Index (0.17 ± 0.18 vs. 0.15 ± 0.14; P = 0.66 [adjusted] and 0.66 [unadjusted]) and Tomographic and Biomechanical Index (0.16 ± 0.19 vs. 0.14 ± 0.19; P = 0.78 [adjusted] and 0.63 [unadjusted]) were not significantly different between case and control groups.

Conclusion

Our study showed that night shifts do not independently affect corneal biomechanical indices.

Hexosamine biosynthetic pathway and O-GlcNAc cycling of glucose metabolism in brain function and disease

Impaired brain glucose metabolism is considered a hallmark of brain dysfunction and neurodegeneration. Disruption of the hexosamine biosynthetic pathway (HBP) and subsequent O-linked N-acetylglucosamine (O-GlcNAc) cycling has been identified as an emerging link between altered glucose metabolism and defects in the brain. Myriads of cytosolic and nuclear proteins in the nervous system are modified at serine or threonine residues with a single N-acetylglucosamine (O-GlcNAc) molecule by O-GlcNAc transferase (OGT), which can be removed by β-N-acetylglucosaminidase (O-GlcNAcase, OGA). Homeostatic regulation of O-GlcNAc cycling is important for the maintenance of normal brain activity. Although significant evidence linking dysregulated HBP metabolism and aberrant O-GlcNAc cycling to induction or progression of neuronal diseases has been obtained, the issue of whether altered O-GlcNAcylation is causal in brain pathogenesis remains uncertain. Elucidation of the specific functions and regulatory mechanisms of individual O-GlcNAcylated neuronal proteins in both normal and diseased states may facilitate the identification of novel therapeutic targets for various neuronal disorders. The information presented in this review highlights the importance of HBP/O-GlcNAcylation in the neuronal system and summarizes the roles and potential mechanisms of O-GlcNAcylated neuronal proteins in maintaining normal brain function and initiation and progression of neurological diseases.

The role of the circadian system in the etiology of depression

Circadian rhythms have evolved in almost all organisms enabling them to anticipate alternating changes in the environment. As a consequence, the circadian clock controls a broad range of bodily functions including appetite, sleep, activity and cortisol levels. The circadian clock synchronizes itself to the external world mainly by environmental light cues and can be disturbed by a variety of factors, including shift-work, jet-lag, stress, ageing and artificial light at night. Interestingly, mood has also been shown to follow a diurnal rhythm. Moreover, circadian disruption has been associated with various mood disorders and patients suffering from depression have irregular biological rhythms in sleep, appetite, activity and cortisol levels suggesting that circadian rhythmicity is crucially involved in the etiology and pathophysiology of depression. The aim of the present review is to give an overview and discuss recent findings in both humans and rodents linking a disturbed circadian rhythm to depression. Understanding the relation between a disturbed circadian rhythm and the etiology of depression may lead to novel therapeutic and preventative strategies.

Modeling the Effects of Napping and Non-napping Patterns of Light Exposure on the Human Circadian Oscillator

In early childhood, consolidation of sleep from a biphasic to a monophasic sleep-wake pattern, that is, the transition from sleeping during an afternoon nap and at night to sleeping only during the night, represents a major developmental milestone. Reduced napping behavior is associated with an advance in the timing of the circadian system; however, it is unknown if this advance represents a standard response of the circadian clock to altered patterns of light exposure or if it additionally reflects features of the developing circadian system. Using a mathematical model of the human circadian pacemaker, we investigated the impact of napping and non-napping patterns of light exposure on entrained circadian phases. Simulated light schedules were based on published data from 20 children (34.2 ± 2.0 months) with habitual napping or non-napping sleep patterns (15 nappers). We found the model predicted different circadian phases for napping and non-napping light patterns: both the decrease in afternoon light during the nap and the increase in evening light associated with napping toddlers' later bedtimes contributed to the observed circadian phase difference produced between napping and non-napping light schedules. We systematically quantified the effects on phase shifting of nap duration, timing, and light intensity, finding larger phase delays occurred for longer and earlier naps. In addition, we simulated phase response curves to a 1-h light pulse and 1-h dark pulse to predict phase and intensity dependence of these changes in light exposure. We found the light pulse produced larger shifts compared with the dark pulse, and we analyzed the model dynamics to identify the features contributing to this asymmetry. These findings suggest that napping status affects circadian timing due to altered patterns of light exposure, with the dynamics of the circadian clock and light processing mediating the effects of the dark pulse associated with a daytime nap.

Calcium Channels and Calcium-Binding Proteins

Signals of nerve impulses are transmitted to excitatory cells to induce the action of organs via the activation of Ca2+ entry through voltage-gated Ca2+ channels (VGCC), which are classified based on their activation threshold into high- and low-voltage activated channels, expressed specifically for each organ [...].

Chronic HDM exposure shows time-of-day and sex-based differences in inflammatory response associated with lung circadian clock disruption

Circadian rhythms and sex differences are involved in the pathophysiology of asthma. Yet, there are no reports that simultaneously address the role of the circadian clock and sex-based differences in chronic house dust mite (HDM)-induced asthma. Here, we sought to determine if chronic HDM exposure during the resting phase (zeitgeber time: ZT0/6:00 a.m.) versus the active phase (ZT12/6:00 p.m.) differentially affects the circadian clock and alters asthma pathobiology in female and male mice. HDM exposure at ZT12 exaggerated infiltration of eosinophil subtypes and associated chemokines in females compared to males. Furthermore, HDM exposure augmented eosinophil chemokines, Th2 gene expression and cytokine release, and humoral immune response in females compared to males at ZT12. Concurrently, histopathological evaluation confirmed increased airway inflammation at ZT12 in both females and males. Overall, we showed a time-of-day response and sex-based differences in HDM-induced exaggerated asthmatic phenotypes (inflammation/remodeling) and circadian clock disruption in females compared to males.

Targeting neuroendocrine abnormalities in Parkinson's disease with exercise

Parkinson's Disease (PD) is a prevalent and complex age-related neurodegenerative condition for which there are no disease-modifying treatments currently available. The pathophysiological process underlying PD remains incompletely understood but increasing evidence points to multiple system dysfunction. Interestingly, the past decade has produced evidence that exercise not only reduces signs and symptoms of PD but is also potentially neuroprotective. Characterizing the mechanistic pathways that are triggered by exercise and lead to positive outcomes will improve understanding of how to counter disease progression and symptomatology. In this review, we highlight how exercise regulates the neuroendocrine system, whose primary role is to respond to stress, maintain homeostasis and improve resilience to aging. We focus on a group of hormones - cortisol, melatonin, insulin, klotho, and vitamin D - that have been shown to associate with various non-motor symptoms of PD, such as mood, cognition, and sleep/circadian rhythm disorder. These hormones may represent important biomarkers to track in clinical trials evaluating effects of exercise in PD with the aim of providing evidence that patients can exert some behavioral-induced control over their disease.

Circadian, hormonal, and sleep rhythms: effects on cancer progression implications for treatment

Circadian, hormonal, and sleep rhythm disruptions are commonly experienced concerns among cancer patients throughout the cancer care continuum. This review aims to summarize the existing literature on circadian, hormonal, and sleep rhythms in the oncological population, focusing on circadian disruption and physiological and psychological abnormalities, disease progression, and chronomodulated treatment approaches. The findings demonstrate that subjectively and objectively measured circadian rhythm disruption is associated with adverse mental health and disease outcomes in patients with cancer. Chronomodulated chemotherapy, light therapy, cognitive behavioral therapy for insomnia, and physical activity have shown evidence of effectiveness in improving sleep, and occasionally, disease outcomes.

Mechanical control of the mammalian circadian clock via YAP/TAZ and TEAD

Autonomous circadian clocks exist in nearly every mammalian cell type. These cellular clocks are subjected to a multilayered regulation sensitive to the mechanochemical cell microenvironment. Whereas the biochemical signaling that controls the cellular circadian clock is increasingly well understood, mechanisms underlying regulation by mechanical cues are largely unknown. Here we show that the fibroblast circadian clock is mechanically regulated through YAP/TAZ nuclear levels. We use high-throughput analysis of single-cell circadian rhythms and apply controlled mechanical, biochemical, and genetic perturbations to study the expression of the clock gene Rev-erbα. We observe that Rev-erbα circadian oscillations are disrupted with YAP/TAZ nuclear translocation. By targeted mutations and overexpression of YAP/TAZ, we show that this mechanobiological regulation, which also impacts core components of the clock such as Bmal1 and Cry1, depends on the binding of YAP/TAZ to the transcriptional effector TEAD. This mechanism could explain the impairment of circadian rhythms observed when YAP/TAZ activity is upregulated, as in cancer and aging.

FoxO3 Modulates Circadian Rhythms in Neural Stem Cells

Both FoxO transcription factors and the circadian clock act on the interface of metabolism and cell cycle regulation and are important regulators of cellular stress and stem cell homeostasis. Importantly, FoxO3 preserves the adult neural stem cell population by regulating cell cycle and cellular metabolism and has been shown to regulate circadian rhythms in the liver. However, whether FoxO3 is a regulator of circadian rhythms in neural stem cells remains unknown. Here, we show that loss of FoxO3 disrupts circadian rhythmicity in cultures of neural stem cells, an effect that is mediated via regulation of Clock transcriptional levels. Using Rev-Erbα-VNP as a reporter, we then demonstrate that loss of FoxO3 does not disrupt circadian rhythmicity at the single cell level. A meta-analysis of published data revealed dynamic co-occupancy of multiple circadian clock components within FoxO3 regulatory regions, indicating that FoxO3 is a Clock-controlled gene. Finally, we examined proliferation in the hippocampus of FoxO3-deficient mice and found that loss of FoxO3 delayed the circadian phase of hippocampal proliferation, indicating that FoxO3 regulates correct timing of NSC proliferation. Taken together, our data suggest that FoxO3 is an integral part of circadian regulation of neural stem cell homeostasis.

Environmental and behavioral regulation of HIF-mitochondria crosstalk

Reduced oxygen availability (hypoxia) can lead to cell and organ damage. Therefore, aerobic species depend on efficient mechanisms to counteract detrimental consequences of hypoxia. Hypoxia inducible factors (HIFs) and mitochondria are integral components of the cellular response to hypoxia and coordinate both distinct and highly intertwined adaptations. This leads to reduced dependence on oxygen, improved oxygen supply, maintained energy provision by metabolic remodeling and tapping into alternative pathways and increased resilience to hypoxic injuries. On one hand, many pathologies are associated with hypoxia and hypoxia can drive disease progression, for example in many cancer and neurological diseases. But on the other hand, controlled induction of hypoxia responses via HIFs and mitochondria can elicit profound health benefits and increase resilience. To tackle pathological hypoxia conditions or to apply health-promoting hypoxia exposures efficiently, cellular and systemic responses to hypoxia need to be well understood. Here we first summarize the well-established link between HIFs and mitochondria in orchestrating hypoxia-induced adaptations and then outline major environmental and behavioral modulators of their interaction that remain poorly understood.

Physiological responses of the cyanobacterium Synechocystis sp. PCC 6803 under rhythmic light variations

Cyanobacteria are challenged by daily fluctuations of light intensities and photoperiod in their natural habitats, which affect the physiology and fitness of cyanobacteria. Circadian rhythms (CRs), an important endogenous process found in all organisms including cyanobacteria, control their physiological activities and helps in coping with 24-h light/dark (LD) cycle. In cyanobacteria, physiological responses under rhythmic ultraviolet radiation (UVR) are poorly studied. Therefore, we studied the changes in photosynthetic pigments, and physiological parameters of Synechocystis sp. PCC 6803 under UVR and photosynthetically active radiation (PAR) of light/dark (LD) oscillations having the combinations of 0, 4:20, 8:16, 12:12, 16:8, 20:4, and 24:24 h. The LD 16:8 enhanced the growth, pigments, proteins, photosynthetic efficiency, and physiology of Synechocystis sp. PCC6803. Continuous light (LL 24) of UVR and PAR exerted negative impact on the photosynthetic pigments, and chlorophyll fluorescence. Significant increase in reactive oxygen species (ROS) resulted in loss of plasma membrane integrity followed by decreased viability of cells. The dark phase played a significant role in Synechocystis to withstand the LL 24 under PAR and UVR. This study offers detailed understanding of the physiological responses of the cyanobacterium to changing light environment.

Circadian control of cisplatin-DNA adduct repair and apoptosis in culture cells

Cisplatin, a widely prescribed chemotherapeutic agent for treating solid tumors, induces DNA adducts and activates cellular defense mechanisms, including DNA repair, cell cycle checkpoint control, and apoptosis. Considering the circadian rhythmicity displayed by most chemotherapeutic agents and their varying therapeutic efficacy based on treatment timing, our study aimed to investigate whether the circadian clock system influences the DNA damage responses triggered by cisplatin in synchronized cells. We examined the DNA damage responses in circadian-synchronized wild-type mouse embryonic fibroblasts (WT-MEF; clock-proficient cells), cryptochrome1 and 2 double knock-out MEF (CRYDKO; clock-deficient cells), and mouse hepatocarcinoma Hepa1c1c7 cells. Varying the treatment time resulted in a significant difference in the rate of platinum-DNA adduct removal specifically in circadian-synchronized WT-MEF, while CRYDKO did not exhibit such variation. Moreover, diurnal variation in other DNA damage responses, such as cell cycle checkpoint activity indicated by p53 phosphorylation status and apoptosis measured by DNA break frequency, was observed only in circadian-synchronized WT-MEF, not in CRYDKO or mouse hepatocarcinoma Hepa1c1c7 cells. These findings highlight that the DNA damage responses triggered by cisplatin are indeed governed by circadian control exclusively in clock-proficient cells. This outcome bears potential implications for enhancing or devising chronotherapy approaches for cancer patients.

Reprogramming of rhythmic liver metabolism by intestinal clock

BACKGROUND & AIMS

Temporal oscillations in intestinal nutrient processing and absorption are coordinated by the local clock, which leads to the hypothesis that the intestinal clock has major impacts on shaping peripheral rhythms via diurnal nutritional signals. Here, we investigate the role of the intestinal clock in controlling liver rhythmicity and metabolism.

METHODS

Transcriptomic analysis, metabolomics, metabolic assays, histology, quantitative (q)PCR, and immunoblotting were performed with Bmal1-intestine-specific knockout (iKO), Rev-erba-iKO, and control mice.

RESULTS

Bmal1 iKO caused large-scale reprogramming of the rhythmic transcriptome of mouse liver with a limited effect on its clock. In the absence of intestinal Bmal1, the liver clock was resistant to entrainment by inverted feeding and a high-fat diet. Importantly, Bmal1 iKO remodelled diurnal hepatic metabolism by shifting to gluconeogenesis from lipogenesis during the dark phase, leading to elevated glucose production (hyperglycaemia) and insulin insensitivity. Conversely, Rev-erba iKO caused a diversion to lipogenesis from gluconeogenesis during the light phase, resulting in enhanced lipogenesis and an increased susceptibility to alcohol-related liver injury. These temporal diversions were attributed to disruption of hepatic SREBP-1c rhythmicity, which was maintained via gut-derived polyunsaturated fatty acids produced by intestinal FADS1/2 under the control of a local clock.

CONCLUSIONS

Our findings establish a pivotal role for the intestinal clock in dictating liver rhythmicity and diurnal metabolism, and suggest targeting intestinal rhythms as a new avenue for improving metabolic health.

IMPACT AND IMPLICATIONS

Our findings establish the centrality of the intestinal clock among peripheral tissue clocks, and associate liver-related pathologies with its malfunction. Clock modifiers in the intestine are shown to modulate liver metabolism with improved metabolic parameters. Such knowledge will help clinicians improve the diagnosis and treatment of metabolic diseases by incorporating intestinal circadian factors.

A minimal model of peripheral clocks reveals differential circadian re-entrainment in aging

The mammalian circadian system comprises a network of endogenous oscillators, spanning from the central clock in the brain to peripheral clocks in other organs. These clocks are tightly coordinated to orchestrate rhythmic physiological and behavioral functions. Dysregulation of these rhythms is a hallmark of aging, yet it remains unclear how age-related changes lead to more easily disrupted circadian rhythms. Using a two-population model of coupled oscillators that integrates the central clock and the peripheral clocks, we derive simple mean-field equations that can capture many aspects of the rich behavior found in the mammalian circadian system. We focus on three age-associated effects that have been posited to contribute to circadian misalignment: attenuated input from the sympathetic pathway, reduced responsiveness to light, and a decline in the expression of neurotransmitters. We find that the first two factors can significantly impede re-entrainment of the clocks following perturbation, while a weaker coupling within the central clock does not affect the recovery rate. Moreover, using our minimal model, we demonstrate the potential of using the feed-fast cycle as an effective intervention to accelerate circadian re-entrainment. These results highlight the importance of peripheral clocks in regulating the circadian rhythm and provide fresh insights into the complex interplay between aging and the resilience of the circadian system.

Integrated multi-omics analysis reveals the molecular interplay between circadian clocks and cancer pathogenesis

Circadian rhythms (CRs) are fundamental biological processes that significantly impact human well-being. Disruption of these rhythms can trigger insufficient neurocognitive development, insomnia, mental disorders, cardiovascular diseases, metabolic dysfunctions, and cancer. The field of chronobiology has increased our understanding of how rhythm disturbances contribute to cancer pathogenesis, and how circadian timing influences the efficacy of cancer treatments. As the circadian clock steadily gains recognition as an emerging factor in tumorigenesis, a thorough and comprehensive multi-omics analysis of CR genes/proteins has never been performed. To shed light on this, we performed, for the first time, an integrated data analysis encompassing genomic/transcriptomic alterations across 32 cancer types (n = 10,918 tumors) taken from the PanCancer Atlas, unfavorable prognostic protein analysis, protein-protein interactomics, and shortest distance score pathways to cancer hallmark phenotypes. This data mining strategy allowed us to unravel 31 essential CR-related proteins involved in the signaling crossroad between circadian rhythms and cancer. In the context of drugging the clock, we identified pharmacogenomic clinical annotations and drugs currently in late phase clinical trials that could be considered as potential cancer therapeutic strategies. These findings highlight the diverse roles of CR-related genes/proteins in the realm of cancer research and therapy.

Circadian rhythms in colonic function

A rhythmic expression of clock genes occurs within the cells of multiple organs and tissues throughout the body, termed "peripheral clocks." Peripheral clocks are subject to entrainment by a multitude of factors, many of which are directly or indirectly controlled by the light-entrainable clock located in the suprachiasmatic nucleus of the hypothalamus. Peripheral clocks occur in the gastrointestinal tract, notably the epithelia whose functions include regulation of absorption, permeability, and secretion of hormones; and in the myenteric plexus, which is the intrinsic neural network principally responsible for the coordination of muscular activity in the gut. This review focuses on the physiological circadian variation of major colonic functions and their entraining mechanisms, including colonic motility, absorption, hormone secretion, permeability, and pain signalling. Pathophysiological states such as irritable bowel syndrome and ulcerative colitis and their interactions with circadian rhythmicity are also described. Finally, the classic circadian hormone melatonin is discussed, which is expressed in the gut in greater quantities than the pineal gland, and whose exogenous use has been of therapeutic interest in treating colonic pathophysiological states, including those exacerbated by chronic circadian disruption.

Chronotype and Cardiometabolic Parameters in Patients with Bipolar Disorder: Preliminary Findings

Cardiometabolic alterations are very common in bipolar disorder (BD). The aim of this study was to investigate the relationship between chronotype and cardiometabolic parameters in patients with a primary diagnosis of BD. This study is an observational clinical investigation including 170 subjects consecutively admitted to the Psychiatric Inpatient Unit of the IRCCS Ospedale Policlinico San Martino (Genoa, Italy), recruited over a period of 48 months. A psychometric tool assessing chronotype was administered and blood tests were performed. Furthermore, the atherogenic coefficient ((total cholesterol-HDL cholesterol)/HDL cholesterol), and Castelli risk index-I (total cholesterol/HDL cholesterol) and -II (LDL cholesterol/HDL cholesterol) were calculated. Patients with BD and an eveningness chronotype showed a higher body mass index, total and low-density lipotrotein cholesterol compared to patients with BD and an intermediate or morning chronotype. Furthermore, the Atherogenic Coefficient and Castelli Risk-Index I-II were found to be higher in bipolar patients with an evening chronotype. The role of chronotype in the development of obesity and cardiovascular risk is, therefore, a relationship worth being investigated, especially in the context of BD, to ameliorate the clinical and therapeutic approach, aiming at increasing the quality of life and reducing the mortality.

Research progresses on the effects of heavy metals on the circadian clock system

Environmental pollution with heavy metals is widespread, thus increasing attention has been paid to their toxic effects. Recent studies have suggested that heavy metals may influence the expression of circadian clock genes. Almost all organs and tissues exhibit circadian rhythms. The normal circadian rhythm of an organism is maintained by the central and peripheral circadian clock. Thus, circadian rhythm disorders perturb normal physiological processes. Here, we review the effects of heavy metals, including manganese, copper, cadmium, and lead, on four core circadian clock genes, i.e., ARNTL, CLOCK, PER, and CRY genes.

The genomic basis of temporal niche evolution in a diurnal rodent

Patterns of diel activity-how animals allocate their activity throughout the 24-h daily cycle-play key roles in shaping the internal physiology of an animal and its relationship with the external environment.1,2,3,4,5 Although shifts in diel activity patterns have occurred numerous times over the course of vertebrate evolution,6 the genomic correlates of such transitions remain unknown. Here, we use the African striped mouse (Rhabdomys pumilio), a species that transitioned from the ancestrally nocturnal diel niche of its close relatives to a diurnal one,7,8,9,10,11 to define patterns of naturally occurring molecular variation in diel niche traits. First, to facilitate genomic analyses, we generate a chromosome-level genome assembly of the striped mouse. Next, using transcriptomics, we show that the switch to daytime activity in this species is associated with a realignment of daily rhythms in peripheral tissues with respect to the light:dark cycle and the central circadian clock. To uncover selection pressures associated with this temporal niche shift, we perform comparative genomic analyses with closely related rodent species and find evidence of relaxation of purifying selection on striped mouse genes in the rod phototransduction pathway. In agreement with this, electroretinogram measurements demonstrate that striped mice have functional differences in dim-light visual responses compared with nocturnal rodents. Taken together, our results show that striped mice have undergone a drastic change in circadian organization and provide evidence that the visual system has been a major target of selection as this species transitioned to a novel temporal niche.

Afterhyperpolarization potential modulated by local [K+]o in K+ diffusion-restricted extracellular space in the central clock of suprachiasmatic nucleus

BACKGROUND

Intercellular coupling is essential for the suprachiasmatic nucleus (SCN) to serve as a coherent central clock. Synaptic release of neurotransmitters and neuropeptides is critical for synchronizing SCN neurons. However, intercellular coupling via non-synaptic mechanisms has also been demonstrated. In particular, the abundant perikaryal appositions with morphological specializations in the narrow extracellular space (ECS) may hinder molecular diffusion to allow for ion accumulation or depletion.

METHODS

The SCN neurons were recorded in the whole-cell current-clamp mode, with pipette filled with high (26 mM)-Na+ or low (6 mM)-Na+ solution.

RESULTS

Cells recorded with high-Na+ pipette solution could fire spontaneous action potentials (AP) with peak AHP more negative than the calculated value of K+ equilibrium potential (EK) and with peak AP more positive than calculated ENa. Cells recorded with low-Na+ pipette solution could also have peak AHP more negative than calculated EK. In contrast, the resting membrane potential (RMP) was always less negative to calculated EK. The distribution and the averaged amplitude of peak AHP, peak AP, or RMP was similar between cells recorded with high-Na+ and low-Na+ solution pipette. In a number of cells, the peak AHP could increase from more positive to become more negative than calculated EK spontaneously or after treatments to hyperpolarize the RMP. TTX blocked the Na+ -dependent APs and tetraethylammonium (TEA), but not Ba2+ or Cd2+, markedly reduced the peak AHP. Perforated-patch cells could also but rarely fire APs with peak AHP more negative than calculated EK.

CONCLUSION

The result of peak AHP negative to calculated EK indicates that local [K+]o sensed by the TEA-sensitive AHP K+ channels must be lower than bulk [K+]o, most likely due to K+ clearance from K+ diffusion-restricted ECS by the Na+/K+-ATPase. The K+ diffusion-restricted ECS may allow for K+-mediated ionic interactions among neurons to regulate SCN excitability.

Efficient assessment of real-world dynamics of circadian rhythms in heart rate and body temperature from wearable data

Laboratory studies have made unprecedented progress in understanding circadian physiology. Quantifying circadian rhythms outside of laboratory settings is necessary to translate these findings into real-world clinical practice. Wearables have been considered promising way to measure these rhythms. However, their limited validation remains an open problem. One major barrier to implementing large-scale validation studies is the lack of reliable and efficient methods for circadian assessment from wearable data. Here, we propose an approximation-based least-squares method to extract underlying circadian rhythms from wearable measurements. Its computational cost is ∼ 300-fold lower than that of previous work, enabling its implementation in smartphones with low computing power. We test it on two large-scale real-world wearable datasets: [Formula: see text] of body temperature data from cancer patients and ∼ 184 000 days of heart rate and activity data collected from the 'Social Rhythms' mobile application. This shows successful extraction of real-world dynamics of circadian rhythms. We also identify a reasonable harmonic model to analyse wearable data. Lastly, we show our method has broad applicability in circadian studies by embedding it into a Kalman filter that infers the state space of the molecular clocks in tissues. Our approach facilitates the translation of scientific advances in circadian fields into actual improvements in health.

Maternal High-Fat Diet Results in Long-Term Sex-Specific Alterations to Metabolic and Gut Microbial Diurnal Oscillations in Adult Offspring

SCOPE

Circadian rhythms profoundly impact metabolism and the gut microbiota. A maternal high-fat diet (HFD) exerts effects on the metabolic syndrome of adult offspring in a sex-specific manner, the underlying mechanisms, however, remain unclear.

METHODS AND RESULTS

Female mice are fed an HFD and raise their offspring on a standard chow diet until 24 weeks. The glucose tolerance, insulin sensitivity, and diurnal rhythms of serum metabolic profiles are assessed in male and female adult offspring. Simultaneously, 16S rRNA is applied to characterize gut microbiota diurnal rhythms. The study finds that maternal HFD tends to deteriorate glucose tolerance and impairs insulin sensitivity in male offspring, but not female offspring, which can be associated with the circadian alterations of serum metabolic profiles in male offspring. As expected, maternal HFD sex-specifically alters diurnal rhythms of the gut microbiota, which exhibits putative associations with metabolic profiles in males.

CONCLUSIONS

The present study identifies the critical role of gut microbiota diurnal rhythms in triggering sex-biased metabolic diurnal rhythms in response to maternal HFD, at least in part. As early life may be a critical window for preventing metabolic diseases, these findings provide the basis for developing chronobiology applications targeting the gut microbiota to combat early metabolic alterations, especially in males.

Metabolism disturbance by light/dark cycle switching depends on the rat health status: the role of grape seed flavanols

Changes in light/dark cycles and obesogenic diets are related to the disruption of circadian rhythms and metabolic disorders. Grape seed flavanols have shown beneficial effects on metabolic diseases and, recently, a circadian system modulation has been suggested to mediate their health-enhancing properties. Therefore, the aim of this study was to evaluate the grape seed (poly)phenol extract (GSPE) effects in healthy and obese rats after a light/dark cycle disruption. Forty-eight rats were fed a standard (STD) or cafeteria (CAF) diet for 6 weeks under STD conditions of a light/dark cycle (12 h light per day, L12). Then, animals were switched to a long (18 h light per day, L18) or short (6 h light per day, L6) photoperiod and administered a vehicle (VH) or GSPE (25 mg kg-1) for 1 week. The results showed changes in serum lipids and insulin and metabolomic profiles dependent on the photoperiod and animal health status. GSPE administration improved serum parameters and increased the Nampt gene expression in CAF rats and modified the metabolomic profile in a photoperiod-dependent manner. Metabolic effects of light/dark disturbance depend on the health status of the rats, with diet-induced CAF-induced obese rats being more affected. Grape seed flavanols improve the metabolic status in a photoperiod-dependent manner and their effects on the circadian system suggest that part of their metabolic effects could be mediated by their action on biological rhythms.

A Review of Evidence for the Involvement of the Circadian Clock Genes into Malignant Transformation of Thyroid Tissue

(1) Background: In 2013, the results of a pioneer study on abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in cancerous thyroid nodules was published. In the following years, new findings suggesting the involvement of circadian clockwork dysfunction into malignant transformation of thyroid tissue were gradually accumulating. This systematic review provides an update on existing evidence regarding the association of these genes with thyroid tumorigenesis. (2) Methods: Two bibliographic databases (Scopus and PubMed) were searched for articles from inception to 20 March 2023. The reference lists of previously published (nonsystematic) reviews were also hand-searched for additional relevant studies. (3) Results: Nine studies published between 2013 and 2022 were selected. In total, 9 of 12 tested genes were found to be either up- or downregulated. The list of such genes includes all families of core circadian clock genes that are the key components of three transcriptional-translational feedback loops of the circadian clock mechanism (BMAL1, CLOCK, NPAS2, RORα, REV-ERBα, PERs, CRYs, and DECs). (4) Conclusions: Examination of abnormalities in the levels and circadian rhythmicity of expression of circadian clock genes in thyroid tissue can help to reduce the rate of inadequate differential preoperative diagnosis for thyroid carcinoma.

The effect of light therapy on sleep quality in cancer patients: a systematic review and meta-analysis of randomized controlled trials

Background

Sleep problem is one of the major issues of cancer patients and may have detrimental effects on the ongoing treatment and recovery of patients. However, the evidence for the effect of light therapy on sleep problems in this population remained scarce. This study aimed to examine the effect of light therapy on self-reported and physiological measures of sleep quality of cancer patients. It also aimed to quantify the magnitude of the effect using a meta-analytical approach.

Methods

Six databases were searched for randomized control trials (RCTs). The primary outcome was the sleep quality using the Pittsburgh sleep quality index (PSQI) measurement of self-reported scores, and the secondary outcomes included total sleep time and sleep efficiency measured by actigraphy. Meta-analyses were performed with the random effects model using the RevMan software. The standardized mean difference (SMD) of the PSQI scores and other measures with their 95% confidence intervals (CIs) were used for assessing the treatment effect (CRD42023370947).

Results

Nine RCTs were identified and included in the study. Light therapy significantly improved the self-reported sleep quality with a reduction of the pooled PSQI score (SMD = -0.72; 95% CI: -1.24 to -0.21; p = 0.006). Regarding total sleep time (p = 0.72) and sleep efficiency (p = 0.47), no significant effects of light therapy were found.

Conclusion

Light therapy could improve self-reported sleep quality in cancer patients. However, due to the heterogeneity and small sample size of the included trials, the results should be interpreted cautiously. Trials with better designs and larger sample sizes are suggested to be conducted for a more definitive conclusion.Systematic review registration:https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=370947.

Actigraphy-derived physical activity levels and circadian rhythm parameters in patients with psoriatic arthritis: relationship with disease activity, mood, age and BMI

Background

Psoriatic arthritis (PsA) is associated with sleep disturbance, depression and a lifetime risk of obesity and cardiovascular disease. To date, there have been no studies investigating the relationship between objectively-measured physical activity (PA) levels and circadian rhythm disturbance with disease activity, daily symptoms and mood in patients with PsA.

Objective

This pilot study aimed to investigate the relationship between disease activity, daily symptoms and mood on PA and circadian rhythm in PsA.

Design

A prospective cohort study recruiting adults with PsA from rheumatology clinics at a single centre in the UK.

Methods

Participants wore an actigraph and recorded their symptoms and mood on a daily basis via a smartphone app for 28 days. Time spent in sedentary, light and moderate-to-vigorous physical activity (MVPA) and parameters reflecting the circadian rhythm of the rest-activity pattern were derived. This included the onset time of the least active 5-h (L5) and most active 10-h (M10) daily consecutive periods and the relative amplitude (RA). The relationship factors between baseline clinical status, daily symptoms, PA and circadian measures were examined using linear mixed effect regression models.

Results

Nineteen participants (8/19 female) were included. Participants with active PsA spent 63.87 min (95% CI: 18.5-109.3, p = 0.008) more in inactivity and 30.78 min (95% CI: 0.4-61.1, p = 0.047) less in MVPA per day compared to those in minimal disease activity (MDA). Age, body mass index and disease duration were also associated with PA duration. Participants with worse functional impairment had an M10 onset time 1.94 h (95% CI: 0.05-3.39, p = 0.011) later than those with no reported functional impairment. No differences were detected for L5 onset time or RA. Higher scores for positive mood components such as feeling energetic, cheerful and elated were associated with less time in inactivity and greater time spent in MVPA overall.

Conclusion

Our study highlights differences in PA and circadian rest-activity pattern timing based on disease activity, disability and daily mood in PsA. Reduced PA levels in patients with active disease may contribute to the observed increased risk of cardiovascular and metabolic sequelae, with further studies exploring this need.

Maternal melatonin levels and temporal dietary intake: results from MY-CARE cohort study

Chrononutrition emerges as a novel approach to promote circadian alignment and metabolic health by means of time-of-the-day dietary intake. However, the relationship between maternal circadian rhythm and temporal dietary intake during pregnancy remains understudied. This study aimed to determine the change in melatonin levels in pregnant women across gestation and its association with temporal energy and macronutrient intake. This was a prospective cohort involving 70 healthy primigravidas. During the second and third trimesters, pregnant women provided salivary samples collected at 9:00, 15:00, 21:00, and 3:00 h over a 24 h day for melatonin assay. Data on chrononutrition characteristics were collected using a 3-day food record. Parameters derived from melatonin measurements including mean, amplitude, maximal level, area under the curve with respect to increase (AUC_I), and area under the curve with respect to ground (AUC_G) were computed. A rhythmic melatonin secretion over the day that remained stable across trimesters was observed among the pregnant women. There was no significant elevation in salivary melatonin levels as pregnancy advanced. In the second trimester, higher energy intake during 12:00-15:59 h and 19:00-06:59 h predicted a steeper melatonin AUC_I (β=-0.32, p = 0.034) and higher AUC_G (β = 0.26, p = 0.042), respectively. Macronutrient intake within 12:00-15:59 h was negatively associated with mean melatonin (Fat: β=-0.28, p = 0.041) and AUC_G (Carbohydrate: β=-0.37, p = 0.003; Protein: β=-0.27, p = 0.036; Fat: β=-0.32, p = 0.014). As pregnant women progressed from the second to the third trimester, a flatter AUC_I was associated with a reduced carbohydrate intake during 12:00-15:59 h (β=-0.40, p = 0.026). No significant association was detected during the third trimester. Our findings show that higher energy and macronutrient intakes particularly during 12:00-15:59 h and 19:00-06:59 h are associated with the disparities in maternal melatonin levels. Findings suggest the potential of time-based dietary approaches to entrain circadian rhythm in pregnant women.

Combining biomechanical stimulation and chronobiology: a novel approach for augmented chondrogenesis?

The unique structure and composition of articular cartilage is critical for its physiological function. However, this architecture may get disrupted by degeneration or trauma. Due to the low intrinsic regeneration properties of the tissue, the healing response is generally poor. Low-grade inflammation in patients with osteoarthritis advances cartilage degradation, resulting in pain, immobility, and reduced quality of life. Generating neocartilage using advanced tissue engineering approaches may address these limitations. The biocompatible microenvironment that is suitable for cartilage regeneration may not only rely on cells and scaffolds, but also on the spatial and temporal features of biomechanics. Cell-autonomous biological clocks that generate circadian rhythms in chondrocytes are generally accepted to be indispensable for normal cartilage homeostasis. While the molecular details of the circadian clockwork are increasingly well understood at the cellular level, the mechanisms that enable clock entrainment by biomechanical signals, which are highly relevant in cartilage, are still largely unknown. This narrative review outlines the role of the biomechanical microenvironment to advance cartilage tissue engineering via entraining the molecular circadian clockwork, and highlights how application of this concept may enhance the development and successful translation of biomechanically relevant tissue engineering interventions.

An integrative mathematical model for timing treatment toxicity and Zeitgeber impact in colorectal cancer cells

Increasing evidence points to a role of the circadian clock in the regulation of cancer hallmarks with a strong impact on the understanding and treatment of this disease. Anti-cancer treatment can be personalized considering treatment timing. Here we present a new mathematical model based on data from three colorectal cancer cell lines and core-clock knock-outs, which couples the circadian and drug metabolism network, and that allows to determine toxicity profiles for a given drug and cell type. Moreover, this model integrates external Zeitgebers and thus may be used to fine-tune toxicity by using external factors, such as light, and therefore, to a certain extent, help fitting the endogenous rhythms of the patients to a defined clinic routine facilitating the implementation of time-dependent treatment in clinical practice.

The association between bedtime at night and diabetes in US adults: Data from National Health and Nutrition Examination Survey (NHANES) 2015-March -2020 pre-pandemic

OBJECTIVE

The purpose of this study was to investigate the relationship between bedtime at night and the risk of diabetes in adults.

METHODS

We extracted data from 14,821 target subjects from the NHANES database for a cross-sectional study. The data on bedtime came from the question in the sleep questionnaire: "What time do you usually fall asleep on weekdays or workdays?". Diabetes was defined as fasting blood sugar ≥ 126mg/dL, or glycohemoglobin ≥ 6.5%, or 2-hour Oral Glucose Tolerance Test blood sugar ≥ 200mg/dL, or taking hypoglycemic agent and insulin, or self-reported diabetes mellitus. A weighted multivariate logistic regression analysis was conducted to explore the relationship between bedtime at night and diabetes in adults.

RESULTS

From 19:00 to 23:00, a significantly negative association can be found between bedtime and diabetes(OR, 0.91 [95%CI, 0.83, 0.99]). From 23:00 to 02:00, The relationship between the two was positive(OR, 1.07 [95%CI, 0.94, 1.22]), nevertheless, the P values was not statistically significant(p = 0.3524). In subgroup analysis, from 19:00-23:00, the relationship was negative across genders, and in males, the P-values were still statistically significant(p = 0.0414). From 23:00-02:00, the relationship was positive across genders.

CONCLUSION

Earlier bedtime (before 23:00) increased the risk of developing diabetes. And this effect was not significantly different between male and female. For bedtime between 23:00-2:00, there was a trend of increasing the risk of diabetes as the bedtime was delayed.

Developmental growth plate cartilage formation suppressed by artificial light at night via inhibiting BMAL1-driven collagen hydroxylation

Exposure to artificial light at night (LAN) can induce obesity, depressive disorder and osteoporosis, but the pernicious effects of excessive LAN exposure on tissue structure are poorly understood. Here, we demonstrated that artificial LAN can impair developmental growth plate cartilage extracellular matrix (ECM) formation and cause endoplasmic reticulum (ER) dilation, which in turn compromises bone formation. Excessive LAN exposure induces downregulation of the core circadian clock protein BMAL1, which leads to collagen accumulation in the ER. Further investigations suggest that BMAL1 is the direct transcriptional activator of prolyl 4-hydroxylase subunit alpha 1 (P4ha1) in chondrocytes, which orchestrates collagen prolyl hydroxylation and secretion. BMAL1 downregulation induced by LAN markedly inhibits proline hydroxylation and transport of collagen from ER to golgi, thereby inducing ER stress in chondrocytes. Restoration of BMAL1/P4HA1 signaling can effectively rescue the dysregulation of cartilage formation within the developmental growth plate induced by artificial LAN exposure. In summary, our investigations suggested that LAN is a significant risk factor in bone growth and development, and a proposed novel strategy targeting enhancement of BMAL1-mediated collagen hydroxylation could be a potential therapeutic approach to facilitate bone growth.

Influence of sunlight on the association between 25-hydroxyvitamin D levels and sleep quality in Brazilian adults: A population-based study

OBJECTIVES

This study aimed to evaluate the association of vitamin D with sleep quality during the COVID-19 pandemic and the influence of daily sunlight on this association.

METHODS

This cross-sectional, population-based study among adults stratified by multistage probability cluster sampling was conducted from October to December 2020 in the Iron Quadrangle region of Brazil. The outcome was sleep quality, evaluated by the Pittsburgh Sleep Quality Index. Vitamin D (25-hydroxyvitamin D) concentrations were determined by indirect electrochemiluminescence and a deficiency was classified as 25(OH)D < 20 ng/mL. To assess sunlight, the average daily sunlight exposure was calculated and was classified as insufficient when less than 30 min/d. Multivariate logistic analysis was used to estimate the association between vitamin D and sleep quality. A directed acyclic graph was used to select minimal and sufficient sets of adjustment variables for confounding from the backdoor criterion.

RESULTS

In a total of 1709 individuals evaluated, the prevalence of vitamin D deficiency was 19.8% (95% CI, 15.5-24.9%), and the prevalence of poor sleep quality was 52.5% (95% CI, 48.6-56.4%). In multivariate analysis, vitamin D was not associated with poor sleep quality in individuals with sufficient sunlight. Moreover, in individuals with insufficient sunlight, vitamin D deficiency was associated with poor sleep quality (odds ratio [OR], 2.02; 95% CI, 1.10-3.71). Furthermore, each 1-ng/mL increase in vitamin D levels reduced the chance of poor sleep quality by 4.2% (OR, 0.96; 95% CI, 0.92-0.99).

CONCLUSIONS

Vitamin D deficiency was associated with poor sleep quality in individuals with insufficient exposure to sunlight.

The relationship between the intake of branched-chain and aromatic amino acids and individuals' sleep quality based on body mass index, gender, and age

Sleep disorder is a relatively common problem that causes chronic conditions such as obesity, diabetes, and cardiovascular diseases. It is believed that diet regulates sleep. So, investigating the relationship between branched-chain amino acids (BCAAs) and aromatic amino acids intake with sleep quality based on age, gender and Body Mass Index (BMI) is important. A total of 172 males and females aged 18-65 participated in this study. The questionnaires were given online to them, included demographic information, food frequency questionnaire (FFQ), International Physical Activity Questionnaire, and Pittsburgh Sleep Quality Index. The Chalder fatigue scale (CFQ) was also used to measure the extent and severity of fatigue. The intake of amino acids was investigated by FFQ. The relationship between amino acids intake and sleep quality was investigated using Pearson's test. The results showed that intake of energy, macronutrients, and some micronutrients had a significant relationship with the quality of sleep of men compared to that of women (P < 0.05). No difference in sleep duration was observed between the two genders. There was a significant, positive association between sleep duration and the intake of BCAA (CC = 0.205, P = 0.031) and aromatic amino acids (CC = 0.22, P = 0.02) in the participants with normal BMI. Significant differences were seen in the intake of BCAA according to BMI which these differences were between lean and obese people, lean and overweight people, obese and normal, and overweight people. It demonstrated that in individuals with normal BMI, amino acids, protein, and carbohydrate intake may affect sleep duration and with modification of these factors sleep quality may get better. More study is needed to confirm these findings.

Subtype-specific circadian clock dysregulation modulates breast cancer biology, invasiveness, and prognosis

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular rhythms in non-cancerous and cancerous human breast tissues are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For non-cancerous tissue, the inferred order of core-circadian genes matches established physiology. Inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of Luminal A samples exhibit continued, albeit disrupted rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among Luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude Luminal A tumors. Patients with high-magnitude tumors had reduced 5-year survival. Correspondingly, 3D Luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

Behavioral and cellular responses to circadian disruption and prenatal immune activation in mice

Most individuals with neurodevelopmental disorders (NDDs), including schizophrenia and autism spectrum disorders, experience disruptions in sleep and circadian rhythms. Epidemiological studies indicate that exposure to prenatal infection increases the risk of developing NDDs. We studied how environmental circadian disruption contributes to NDDs using maternal immune activation (MIA) in mice, which models prenatal infection. Pregnant dams were injected with viral mimetic poly IC (or saline) at E9.5. Adult poly IC- and saline-exposed offspring were subjected to 4 weeks of each of the following: standard lighting (LD1), constant light (LL) and standard lighting again (LD2). Behavioral tests were conducted in the last 12 days of each condition. Poly IC exposure led to significant behavioral differences, including reduced sociability (males only) and deficits in prepulse inhibition. Interestingly, poly IC exposure led to reduced sociability specifically when males were tested after LL exposure. Mice were exposed again to either LD or LL for 4 weeks and microglia were characterized. Notably, poly IC exposure led to increased microglial morphology index and density in dentate gyrus, an effect attenuated by LL exposure. Our findings highlight interactions between circadian disruption and prenatal infection, which has implications in informing the development of circadian-based therapies for individuals with NDDs.

Single-nucleus transcriptome analysis reveals transcriptional profiles of circadian clock and pain related genes in human and mouse trigeminal ganglion

Introduction

Clinical studies have revealed the existence of circadian rhythms in pain intensity and treatment response for chronic pain, including orofacial pain. The circadian clock genes in the peripheral ganglia are involved in pain information transmission by modulating the synthesis of pain mediators. However, the expression and distribution of clock genes and pain-related genes in different cell types within the trigeminal ganglion, the primary station of orofacial sensory transmission, are not yet fully understood.

Methods

In this study, data from the normal trigeminal ganglion in the Gene Expression Omnibus (GEO) database were used to identify cell types and neuron subtypes within the human and mouse trigeminal ganglion by single nucleus RNA sequencing analysis. In the subsequent analyses, the distribution of the core clock genes, pain-related genes, and melatonin and opioid-related genes was assessed in various cell clusters and neuron subtypes within the human and mouse trigeminal ganglion. Furthermore, the statistical analysis was used to compare the differences in the expression of pain-related genes in the neuron subtypes of trigeminal ganglion.

Results

The present study provides comprehensive transcriptional profiles of core clock genes, pain-related genes, melatonin-related genes, and opioid-related genes in different cell types and neuron subtypes within the mouse and human trigeminal ganglion. A comparative analysis of the distribution and expression of the aforementioned genes was conducted between human and mouse trigeminal ganglion to investigate species differences.

Discussion

Overall, the results of this study serve as a primary and valuable resource for exploring the molecular mechanisms underlying oral facial pain and pain rhythms.