REV-ERBα influences the stability and nuclear localization of the glucocorticoid receptor

Recent Advances in Hepatic Metabolic Regulation by the Nuclear Factor Rev-erbɑ

Rev-erbɑ (NR1D1) is a nuclear receptor superfamily member that plays a vital role in mammalian molecular clocks and metabolism. Rev-erbɑ can regulate the metabolism of drugs and the body's glucose metabolism, lipid metabolism, and adipogenesis. It is even one of the important regulatory factors regulating the occurrence of metabolic diseases (e.g., diabetes, fatty liver). Metabolic enzymes mediate most drug metabolic reactions in the body. Rev-erbɑ has been recognized to regulate drug metabolic enzymes (such as Cyp2b10 and Ugt1a9). Therefore, this paper mainly reviewed that Rev-erbɑ regulates I and II metabolic enzymes in the liver to affect drug pharmacokinetics. The expression of these drug metabolic enzymes (up-regulated or down-regulated) is related to drug exposure and effects/ toxicity. In addition, our discussion extends to Rev-erbɑ regulating some transporters (such as P-gp, Mrp2, and Bcrp), as they also play an essential role in drug metabolism. Finally, we briefly describe the role and mechanism of nuclear receptor Rev-erbɑ in lipid and glucose homeostasis, obesity, and metabolic disorders syndrome. In conclusion, this paper aims to understand better the role and mechanism of Rev-erbɑ in regulating drug metabolism, lipid, glucose homeostasis, obesity, and metabolic disorders syndrome, which explores how to target Rev-erbɑ to guide the design and development of new drugs and provide scientific reference for the molecular mechanism of new drug development, rational drug use, and drug interaction.

Glucocorticoid receptor-mediated Nr1d1 chromatin circadian misalignment in stress-induced irritable bowel syndrome

Stress-elevated glucocorticoids cause circadian disturbances and gut-brain axis (GBA) disorders, including irritable bowel syndrome (IBS). We hypothesized that the glucocorticoid receptor (GR/NR3C1) might cause chromatin circadian misalignment in the colon epithelium. We observed significantly decreased core circadian gene Nr1d1 in water avoidance stressed (WAS) BALB/c colon epithelium, like in IBS patients. WAS decreased GR binding at the Nr1d1 promoter E-box (enhancer box), and GR could suppress Nr1d1 via this site. Stress also altered GR binding at the E-box sites along the Ikzf3-Nr1d1 chromatin and remodeled circadian chromatin 3D structures, including Ikzf3-Nr1d1 super-enhancer, Dbp, and Npas2. Intestinal deletion of Nr3c1 specifically abolished these stress-induced transcriptional alternations relevant to IBS phenotypes in BALB/c mice. GR mediated Ikzf3-Nr1d1 chromatin disease related circadian misalignment in stress-induced IBS animal model. This animal model dataset suggests that regulatory SNPs of human IKZF3-NR1D1 transcription through conserved chromatin looping have translational potential based on the GR-mediated circadian-stress crosstalk.

Circadian glucocorticoids throughout development

Glucocorticoids (GCs) are essential drivers of mammalian tissue growth and maturation during one of the most critical developmental windows, the perinatal period. The developing circadian clock is shaped by maternal GCs. GC deficits, excess, or exposure at the wrong time of day leads to persisting effects later in life. During adulthood, GCs are one of the main hormonal outputs of the circadian system, peaking at the beginning of the active phase (i.e., the morning in humans and the evening in nocturnal rodents) and contributing to the coordination of complex functions such as energy metabolism and behavior, across the day. Our article discusses the current knowledge on the development of the circadian system with a focus on the role of GC rhythm. We explore the bidirectional interaction between GCs and clocks at the molecular and systemic levels, discuss the evidence of GC influence on the master clock in the suprachiasmatic nuclei (SCN) of the hypothalamus during development and in the adult system.

Muscle mitochondrial remodeling by intermittent glucocorticoid drugs requires an intact circadian clock and muscle PGC1α

Exogenous glucocorticoids interact with the circadian clock, but little attention is paid to the timing of intake. We recently found that intermittent once-weekly prednisone improved nutrient oxidation in dystrophic muscle. Here, we investigated whether dosage time affected prednisone effects on muscle bioenergetics. In mice treated with once-weekly prednisone, drug dosing in the light-phase promoted nicotinamide adenine dinucleotide (NAD+) levels and mitochondrial function in wild-type muscle, while this response was lost with dark-phase dosing. These effects depended on a normal circadian clock since they were disrupted in muscle from [Brain and muscle Arnt-like protein-1 (Bmal1)]-knockout mice. The light-phase prednisone pulse promoted BMAL1-dependent glucocorticoid receptor recruitment on noncanonical targets, including Nampt and Ppargc1a [peroxisome proliferator-activated receptor-γ coactivator 1α (PGC1α)]. In mice with muscle-restricted inducible PGC1α ablation, bioenergetic stimulation by light-phase prednisone required PGC1α. These results demonstrate that glucocorticoid "chronopharmacology" for muscle bioenergetics requires an intact clock and muscle PGC1α activity.

The Circadian Clock and Obesity

The modern way of life has dramatically affected our biological rhythms. Circadian rhythms, which are generated by an endogenous circadian clock, are observed in a large number of physiological functions including metabolism. Proper peripheral clock synchronization by different signals including appropriate feeding/fasting cycles is essential to coordinate and temporally gate metabolic processes. In this chapter, we emphasize the importance of nutrient sensing by peripheral clocks and highlight the major role of peripheral and central clock communication to locally regulate metabolic processes and ensure optimal energy storage and expenditure. As a consequence, changes in eating behavior and/or bedtime, as occurs upon shift work and jet lag, have direct consequences on metabolism and participate in the increasing prevalence of obesity and associated metabolic diseases such as type 2 diabetes and non-alcoholic fatty liver disease. In this setting, time-restricted feeding has been suggested as an efficient approach to ameliorate metabolic parameters and control body weight.

The trophoblast clock controls transport across placenta in mice

In mammals, 24-h rhythms of physiology and behavior are organized by a body-wide network of clock genes and proteins. Despite the well-known function of the adult circadian system, the roles of maternal, fetal and placental clocks during pregnancy are poorly defined. In the mature mouse placenta, the labyrinth zone (LZ) is of fetal origin and key for selective nutrient and waste exchange. Recently, clock gene expression has been detected in LZ and other fetal tissues; however, there is no evidence of a placental function controlled by the LZ clock. Here, we demonstrate that specifically the trophoblast layer of the LZ harbors an already functional clock by late gestation, able to regulate in a circadian manner the expression and activity of the xenobiotic efflux pump, ATP-binding cassette sub-family B member 1 (ABCB1), likely gating the fetal exposure to drugs from the maternal circulation to certain times of the day. As more than 300 endogenous and exogenous compounds are substrates of ABCB1, our results might have implications in choosing the maternal treatment time when aiming either maximal/minimal drug availability to the fetus/mother.

Multifaceted Control of GR Signaling and Its Impact on Hepatic Transcriptional Networks and Metabolism

Glucocorticoids (GCs) and the glucocorticoid receptor (GR) are important regulators of development, inflammation, stress response and metabolism, demonstrated in various diseases including Addison's disease, Cushing's syndrome and by the many side effects of prolonged clinical administration of GCs. These conditions include severe metabolic challenges in key metabolic organs like the liver. In the liver, GR is known to regulate the transcription of key enzymes in glucose and lipid metabolism and contribute to the regulation of circadian-expressed genes. Insights to the modes of GR regulation and the underlying functional mechanisms are key for understanding diseases and for the development of improved clinical uses of GCs. The activity and function of GR is regulated at numerous levels including ligand availability, interaction with heat shock protein (HSP) complexes, expression of GR isoforms and posttranslational modifications. Moreover, recent genomics studies show functional interaction with multiple transcription factors (TF) and coregulators in complex transcriptional networks controlling cell type-specific gene expression by GCs. In this review we describe the different regulatory steps important for GR activity and discuss how different TF interaction partners of GR selectively control hepatic gene transcription and metabolism.

The circadian phase of antenatal glucocorticoid treatment affects the risk of behavioral disorders

During pregnancy, maternal endocrine signals drive fetal development and program the offspring's physiology. A disruption of maternal glucocorticoid (GC) homeostasis increases the child's risk of developing psychiatric disorders later in life. We here show in mice, that the time of day of antenatal GC exposure predicts the behavioral phenotype of the adult offspring. Offspring of mothers receiving GCs out-of-phase compared to their endogenous circadian GC rhythm show elevated anxiety, impaired stress coping, and dysfunctional stress-axis regulation. The fetal circadian clock determines the vulnerability of the stress axis to GC treatment by controlling GC receptor (GR) availability in the hypothalamus. Similarly, a retrospective observational study indicates poorer stress compensatory capacity in 5-year old preterm infants whose mothers received antenatal GCs towards the evening. Our findings offer insights into the circadian physiology of feto-maternal crosstalk and assign a role to the fetal clock as a temporal gatekeeper of GC sensitivity.

Vitamin D Supplementation Rescues Aberrant NF-κB Pathway Activation and Partially Ameliorates Rett Syndrome Phenotypes in Mecp2 Mutant Mice

Rett syndrome (RTT) is a severe, progressive X-linked neurodevelopmental disorder caused by mutations in the transcriptional regulator MECP2. We previously identified aberrant NF-κB pathway upregulation in brains of Mecp2-null mice and demonstrated that genetically attenuating NF-κB rescues some characteristic neuronal RTT phenotypes. These results raised the intriguing question of whether NF-κB pathway inhibitors might provide a therapeutic avenue in RTT. Here, we investigate whether the known NF-κB pathway inhibitor vitamin D ameliorates neuronal phenotypes in Mecp2-mutant mice. Vitamin D deficiency is prevalent among RTT patients, and we find that Mecp2-null mice similarly have significantly reduced 25(OH)D serum levels compared with wild-type littermates. We identify that vitamin D rescues aberrant NF-κB pathway activation and reduced neurite outgrowth of Mecp2 knock-down cortical neurons in vitro. Further, dietary supplementation with vitamin D in early symptomatic male Mecp2 hemizygous null and female Mecp2 heterozygous mice ameliorates reduced neocortical dendritic morphology and soma size phenotypes and modestly improves reduced lifespan of Mecp2-nulls. These results elucidate fundamental neurobiology of RTT and provide foundation that NF-κB pathway inhibition might be a therapeutic target for RTT.

Insights About Circadian Clock and Molecular Pathogenesis in Gliomas

The circadian clock is an endogenous time-keeping system that has been discovered across kingdoms of life. It controls and coordinates metabolism, physiology, and behavior to adapt to variations within the day and the seasonal environmental cycles driven by earth rotation. In mammals, although circadian rhythm is controlled by a set of core clock genes that are present in both in suprachiasmatic nucleus (SCN) of the hypothalamus and peripheral tissues, the generation and control of the circadian rhythm at the cellular, tissue, and organism levels occurs in a hierarchal fashion. The SCN is central pacemaker comprising the principal circadian clock that synchronizes peripheral circadian clocks to their appropriate phase. Different epidemiological studies have shown that disruption of normal circadian rhythm is implicated in increasing the risk of developing cancers. In addition, deregulated expression of clock genes has been demonstrated in various types of cancer. These findings indicate a close association between circadian clock and cancer development and progression. Here, we review different evidences of this association in relation to molecular pathogenesis in gliomas.

Why Lungs Keep Time: Circadian Rhythms and Lung Immunity

Circadian rhythms are daily cycles in biological function that are ubiquitous in nature. Understood as a means for organisms to anticipate daily environmental changes, circadian rhythms are also important for orchestrating complex biological processes such as immunity. Nowhere is this more evident than in the respiratory system, where circadian rhythms in inflammatory lung disease have been appreciated since ancient times. In this focused review we examine how emerging research on circadian rhythms is being applied to the study of fundamental lung biology and respiratory disease. We begin with a general introduction to circadian rhythms and the molecular circadian clock that underpins them. We then focus on emerging data tying circadian clock function to immunologic activities within the respiratory system. We conclude by considering outstanding questions about biological timing in the lung and how a better command of chronobiology could inform our understanding of complex lung diseases.

Mood-related central and peripheral clocks

Mood disorders, including major depression, bipolar disorder, and seasonal affective disorder, are debilitating disorders that affect a significant portion of the global population. Individuals suffering from mood disorders often show significant disturbances in circadian rhythms and sleep. Moreover, environmental disruptions to circadian rhythms can precipitate or exacerbate mood symptoms in vulnerable individuals. Circadian clocks exist throughout the central nervous system and periphery, where they regulate a wide variety of physiological processes implicated in mood regulation. These processes include monoaminergic and glutamatergic transmission, hypothalamic-pituitary-adrenal axis function, metabolism, and immune function. While there seems to be a clear link between circadian rhythm disruption and mood regulation, the mechanisms that underlie this association remain unclear. This review will touch on the interactions between the circadian system and each of these processes and discuss their potential role in the development of mood disorders. While clinical studies are presented, much of the review will focus on studies in animal models, which are attempting to elucidate the molecular and cellular mechanisms in which circadian genes regulate mood.

Circadian Clock Regulation of Hepatic Energy Metabolism Regulatory Circuits

The liver is a critical organ of energy metabolism. At least 10% of the liver transcriptome demonstrates rhythmic expression, implying that the circadian clock regulates large programmes of hepatic genes. Here, we review the mechanisms by which this rhythmic regulation is conferred, with a particular focus on the transcription factors whose actions combine to impart liver- and time-specificity to metabolic gene expression.

REV-ERBα and REV-ERBβ function as key factors regulating Mammalian Circadian Output

The circadian clock regulates behavioural and physiological processes in a 24-h cycle. The nuclear receptors REV-ERBα and REV-ERBβ are involved in the cell-autonomous circadian transcriptional/translational feedback loops as transcriptional repressors. A number of studies have also demonstrated a pivotal role of REV-ERBs in regulation of metabolic, neuronal, and inflammatory functions including bile acid metabolism, lipid metabolism, and production of inflammatory cytokines. Given the multifunctional role of REV-ERBs, it is important to elucidate the mechanism through which REV-ERBs exert their functions. To this end, we established a Rev-erbα/Rev-erbβ double-knockout mouse embryonic stem (ES) cell model and analyzed the circadian clock and clock-controlled output gene expressions. A comprehensive mRNA-seq analysis revealed that the double knockout of both Rev-erbα and Rev-erbβ does not abrogate expression rhythms of E-box-regulated core clock genes but drastically changes a diverse set of other rhythmically-expressed output genes. Of note, REV-ERBα/β deficiency does not compromise circadian expression rhythms of PER2, while REV-ERB target genes, Bmal1 and Npas2, are significantly upregulated. This study highlight the relevance of REV-ERBs as pivotal output mediators of the mammalian circadian clock.

Multilevel Interactions of Stress and Circadian System: Implications for Traumatic Stress

The dramatic fluctuations in energy demands by the rhythmic succession of night and day on our planet has prompted a geophysical evolutionary need for biological temporal organization across phylogeny. The intrinsic circadian timing system (CS) represents a highly conserved and sophisticated internal "clock," adjusted to the 24-h rotation period of the earth, enabling a nyctohemeral coordination of numerous physiologic processes, from gene expression to behavior. The human CS is tightly and bidirectionally interconnected to the stress system (SS). Both systems are fundamental for survival and regulate each other's activity in order to prepare the organism for the anticipated cyclic challenges. Thereby, the understanding of the temporal relationship between stressors and stress responses is critical for the comprehension of the molecular basis of physiology and pathogenesis of disease. A critical loss of the harmonious timed order at different organizational levels may affect the fundamental properties of neuroendocrine, immune, and autonomic systems, leading to a breakdown of biobehavioral adaptative mechanisms with increased stress sensitivity and vulnerability. In this review, following an overview of the functional components of the SS and CS, we present their multilevel interactions and discuss how traumatic stress can alter the interplay between the two systems. Circadian dysregulation after traumatic stress exposure may represent a core feature of trauma-related disorders mediating enduring neurobiological correlates of trauma through maladaptive stress regulation. Understanding the mechanisms susceptible to circadian dysregulation and their role in stress-related disorders could provide new insights into disease mechanisms, advancing psychochronobiological treatment possibilities and preventive strategies in stress-exposed populations.

Combinatorial regulation of hepatic cytoplasmic signaling and nuclear transcriptional events by the OGT/REV-ERBα complex

The nuclear receptor REV-ERBα integrates the circadian clock with hepatic glucose and lipid metabolism by nucleating transcriptional comodulators at genomic regulatory regions. An interactomic approach identified O-GlcNAc transferase (OGT) as a REV-ERBα-interacting protein. By shielding cytoplasmic OGT from proteasomal degradation and favoring OGT activity in the nucleus, REV-ERBα cyclically increased O-GlcNAcylation of multiple cytoplasmic and nuclear proteins as a function of its rhythmically regulated expression, while REV-ERBα ligands mostly affected cytoplasmic OGT activity. We illustrate this finding by showing that REV-ERBα controls OGT-dependent activities of the cytoplasmic protein kinase AKT, an essential relay in insulin signaling, and of ten-of-eleven translocation (TET) enzymes in the nucleus. AKT phosphorylation was inversely correlated to REV-ERBα expression. REV-ERBα enhanced TET activity and DNA hydroxymethylated cytosine (5hmC) levels in the vicinity of REV-ERBα genomic binding sites. As an example, we show that the REV-ERBα/OGT complex modulates SREBP-1c gene expression throughout the fasting/feeding periods by first repressing AKT phosphorylation and by epigenomically priming the Srebf1 promoter for a further rapid response to insulin. Conclusion: REV-ERBα regulates cytoplasmic and nuclear OGT-controlled processes that integrate at the hepatic SREBF1 locus to control basal and insulin-induced expression of the temporally and nutritionally regulated lipogenic SREBP-1c transcript.

REVERBa couples the circadian clock to hepatic glucocorticoid action

The glucocorticoid receptor (GR) is a major drug target in inflammatory disease. However, chronic glucocorticoid (GC) treatment leads to disordered energy metabolism, including increased weight gain, adiposity, and hepatosteatosis — all programs modulated by the circadian clock. We demonstrated that while antiinflammatory GC actions were maintained irrespective of dosing time, the liver was significantly more GC sensitive during the day. Temporal segregation of GC action was underpinned by a physical interaction of GR with the circadian transcription factor REVERBa and co-binding with liver-specific hepatocyte nuclear transcription factors (HNFs) on chromatin. REVERBa promoted efficient GR recruitment to chromatin during the day, acting in part by maintaining histone acetylation, with REVERBa-dependent GC responses providing segregation of carbohydrate and lipid metabolism. Importantly, deletion of Reverba inverted circadian liver GC sensitivity and protected mice from hepatosteatosis induced by chronic GC administration. Our results reveal a mechanism by which the circadian clock acts through REVERBa in liver on elements bound by HNF4A/HNF6 to direct GR action on energy metabolism.

Circadian variation in pulmonary inflammatory responses is independent of rhythmic glucocorticoid signaling in airway epithelial cells

The circadian clock is a critical regulator of immune function. We recently highlighted a role for the circadian clock in a mouse model of pulmonary inflammation. The epithelial clock protein Bmal1 was required to regulate neutrophil recruitment in response to inflammatory challenge. Bmal1 regulated glucocorticoid receptor (GR) recruitment to the neutrophil chemokine, CXC chemokine ligand 5 (CXCL5), providing a candidate mechanism. We now show that clock control of pulmonary neutrophilia persists without rhythmic glucocorticoid availability. Epithelial GR-null mice had elevated expression of proinflammatory chemokines in the lung under homeostatic conditions. However, deletion of GR in the bronchial epithelium blocked rhythmic CXCL5 production, identifying GR as required to confer circadian control to CXCL5. Surprisingly, rhythmic pulmonary neutrophilia persisted, despite nonrhythmic CXCL5 responses, indicating additional circadian control mechanisms. Deletion of GR in myeloid cells alone did not prevent circadian variation in pulmonary neutrophilia and showed reduced neutrophilic inflammation in response to dexamethasone treatment. These new data show GR is required to confer circadian control to some inflammatory chemokines, but that this alone is insufficient to prevent circadian control of neutrophilic inflammation in response to inhaled LPS, with additional control mechanisms arising in the myeloid cell lineage.—Ince, L. M., Zhang, Z., Beesley, S., Vonslow, R. M., Saer, B. R., Matthews, L. C., Begley, N., Gibbs, J. E., Ray, D. W., Loudon, A. S. I. Circadian variation in pulmonary inflammatory responses is independent of rhythmic glucocorticoid signaling in airway epithelial cells.

Perinatal Programming of Circadian Clock-Stress Crosstalk

An intact communication between circadian clocks and the stress system is important for maintaining physiological homeostasis under resting conditions and in response to external stimuli. There is accumulating evidence for a reciprocal interaction between both-from the systemic to the molecular level. Disruption of this interaction by external factors such as shiftwork, jetlag, or chronic stress increases the risk of developing metabolic, immune, or mood disorders. From experiments in rodents, we know that both systems maturate during the perinatal period. During that time, exogenous factors such as stress or alterations in the external photoperiod may critically affect-or program-physiological functions later in life. This developmental programming process has been attributed to maternal stress signals reaching the embryo, which lastingly change gene expression through the induction of epigenetic mechanisms. Despite the well-known function of the adult circadian system in temporal coordination of physiology and behavior, the role of maternal and embryonic circadian clocks during pregnancy and postnatal development is still poorly defined. A better understanding of the circadian-stress crosstalk at different periods of development may help to improve stress resistance and devise preventive and therapeutic strategies against chronic stress-associated disorders.

Rev-erb-α regulates atrophy-related genes to control skeletal muscle mass

The nuclear receptor Rev-erb-α modulates hepatic lipid and glucose metabolism, adipogenesis and thermogenesis. We have previously demonstrated that Rev-erb-α is also an important regulator of skeletal muscle mitochondrial biogenesis and function, and autophagy. As such, Rev-erb-α over-expression in skeletal muscle or its pharmacological activation improved mitochondrial respiration and enhanced exercise capacity. Here, in gain- and loss-of function studies, we show that Rev-erb-α also controls muscle mass. Rev-erb-α-deficiency in skeletal muscle leads to increased expression of the atrophy-related genes (atrogenes), associated with reduced muscle mass and decreased fiber size. By contrast, in vivo and in vitro Rev-erb-α over-expression results in reduced atrogenes expression and increased fiber size. Finally, Rev-erb-α pharmacological activation blocks dexamethasone-induced upregulation of atrogenes and muscle atrophy. This study identifies Rev-erb-α as a promising pharmacological target to preserve muscle mass.

Unique Interactome Network Signatures for Peroxisome Proliferator-activated Receptor Gamma (PPARγ) Modulation by Functional Selective Ligands

The nuclear receptor PPARγ regulates adipogenesis and plays a central role in lipid and glucose homeostasis, and is the molecular target of the glitazones (TZDs), therapeutics used to treat insulin resistance and type-2 diabetes (T2D). Although the TZDs, which are PPARγ agonists, demonstrated robust clinical efficacy in T2D, their use has been hampered by an array of untoward side effects. Paradoxically, partial agonists (e.g. MRL24), antagonists (e.g. SR1664), and inverse agonists (e.g. SR10171 and SR2595), possess similar insulin-sensitizing efficacy as the TZDs in obese diabetic mice. Given the unique pharmacology of these modulators, we sought to identify the components of the PPARγ transcriptional complex that is regulated by these ligands. To achieve this, we employed subcellular fractionation of adipocytes combined with either trapping of the receptor complex on biotinylated DNA oligonucleotide, or classical immunoprecipitation. Tandem mass spectrometry analysis revealed unique, partially overlapping, compound- and subcellular compartment-specific complexes. Components of these interactomes are putative coregulators of PPARγ. Interestingly, complexes isolated in the cytosol contain sets of proteins involve in cellular assembly and extracellular matrix. Furthermore, the interactome observed for cytosolic non-DNA bound receptor was distinct from that observed from nuclear chromatin associated PPARγ, suggesting cellular compartment-specific roles for this receptor.

Molecular Mechanisms in Mood Regulation Involving the Circadian Clock

The circadian system coordinates activities and functions in cells and tissues in order to optimize body functions in anticipation to daily changes in the environment. Disruption of the circadian system, due to irregular lifestyle such as rotating shift work, frequent travel across time-zones, or chronic stress, is correlated with several diseases such as obesity, cancer, and neurological disorders. Molecular mechanisms linking the circadian clock with neurological functions have been uncovered suggesting that disruption of the clock may be critically involved in the development of mood disorders. In this mini-review, I will summarize molecular mechanisms in which clock components play a central role for mood regulation. Such mechanisms have been identified in the monoaminergic system, the HPA axis, and neurogenesis.

Circadian physiology of metabolism

A majority of mammalian genes exhibit daily fluctuations in expression levels, making circadian expression rhythms the largest known regulatory network in normal physiology. Cell-autonomous circadian clocks interact with daily light-dark and feeding-fasting cycles to generate approximately 24-hour oscillations in the function of thousands of genes. Circadian expression of secreted molecules and signaling components transmits timing information between cells and tissues. Such intra- and intercellular daily rhythms optimize physiology both by managing energy use and by temporally segregating incompatible processes. Experimental animal models and epidemiological data indicate that chronic circadian rhythm disruption increases the risk of metabolic diseases. Conversely, time-restricted feeding, which imposes daily cycles of feeding and fasting without caloric reduction, sustains robust diurnal rhythms and can alleviate metabolic diseases. These findings highlight an integrative role of circadian rhythms in physiology and offer a new perspective for treating chronic diseases in which metabolic disruption is a hallmark.