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

Decoding the Liver-Heart Axis in Cardiometabolic Diseases

The liver and heart are closely interconnected organs, and their bidirectional interaction plays a central role in cardiometabolic disease. In this review, we summarize current evidence linking liver dysfunction-particularly metabolic dysfunction-associated steatotic liver disease, alcohol-associated liver disease, and cirrhosis-with an increased risk of heart failure and other cardiovascular diseases. We discuss how these liver conditions contribute to cardiac remodeling, systemic inflammation, and hemodynamic stress and how cardiac dysfunction in turn impairs liver perfusion and promotes hepatic injury. Particular attention is given to the molecular mediators of liver-heart communication, including hepatokines and cardiokines, as well as the emerging role of advanced research methodologies, including omics integration, proximity labeling, and organ-on-chip platforms, that are redefining our understanding of interorgan cross talk. By integrating mechanistic insights with translational tools, this review aims to support the development of multiorgan therapeutic strategies for cardiometabolic disease.

Sleep Duration, Midpoint, Variability, Irregularity and Metabolic Dysfunction-Associated Steatotic Liver Disease

OBJECTIVES

The relationship between actigraphy-derived sleep parameters, day-to-day deviations in sleep parameters, and metabolic dysfunction-associated steatotic liver disease (MASLD), a new definition of nonalcoholic fatty liver disease (NAFLD), remains unclear. We aimed to explore the associations of sleep duration, midpoint, variability and irregularity with MASLD risk.

METHODS

We used data from the National Health and Nutrition Examination Survey (NHANES) 2011-2014. Sleep duration and midpoint were estimated from 4 to 7 days of 24-hour actigraphy measurements. Sleep duration and midpoint standard deviation were used as indicators of sleep variability and irregularity, respectively. MASLD was diagnosed according to the multi-society Delphi consensus. Hepatic steatosis was defined as fatty liver index ≥ 60. Multivariable weighted logistic regression models were used to explore correlations and perform subgroup analyses.

RESULTS

A total of 5,316 participants were included, of whom 2,339 had MASLD. After adjusting for socio-demographic characteristics, lifestyle factors, and depression, compared to sleep variability < 60 minutes, the odds ratio (OR) [95% confidence interval (CI)] was 1.13 (0.96-1.34) for 60-90 minutes, and 1.17 (1.00-1.38) for > 90 minutes (P for trend = .034). After further adjustment for other sleep variables, short sleep duration (<7 hours) was associated with a 24% higher risk of MASLD (OR: 1.24, 95% CI: 1.01-1.53); compared to sleep irregularity < 38 minutes, OR (95% CI) was 1.27 (1.02-1.59) for 38-61 minutes and 1.43 (1.24-1.65) for > 61 minutes (P for trend = .003).

CONCLUSION

In addition to sleep duration, sleep irregularity may need to be considered in the prevention of MASLD.

Dihydroartemisinin requires NR1D1 mediated Rab7 ubiquitination to regulate hepatic stellate cells lipophagy in liver fibrosis

The activation of hepatic stellate cells (HSCs) is a core event in the pathogenesis of liver fibrosis, typically accompanied by the disappearance of lipid droplets (LDs). Reversing the disappearance of HSCs LDs is a strategy to inhibit HSCs activation and alleviate liver fibrosis. Previous studies have shown that nuclear receptor subfamily 1 group d member 1 (NR1D1), as an important component of the biological clock system, is closely related to lipid metabolism. Our previous evidence indicated that Dihydroartemisinin (DHA) can regulate the lipid droplet metabolism of activated HSCs. Moreover, in CCl4 induced liver fibrosis mice, the liver clock gene NR1D1 is dysregulated. On this basis we explored the potential molecular mechanism of DHA inhibiting liver fibrosis through NR1D1. We found that DHA can inhibit liver fibrosis by restoring activated LDs of HSCs through inhibiting HSCs lipophagy. In summary, our study emphasizes the importance of NR1D1 in liver fibrosis and the potential of DHA to regulate NR1D1 in the treatment of liver fibrosis, providing a new direction for the treatment of liver fibrosis.

Circadian clock controlled glycolipid metabolism and its relevance to disease management

The circadian clock is a critical regulator of physiological rhythms, orchestrating metabolic processes to adapt to daily environmental changes. This review focuses on the intricate relationship between circadian regulation and glycolipid metabolism, with implications for metabolic diseases. Central and peripheral clocks coordinate the rhythmic expression of key enzymes and transporters, ensuring glycolipid homeostasis. Disruptions to these rhythms can result in metabolic disorders characterized by altered glucose utilization, insulin sensitivity, and lipid storage. The molecular mechanisms underlying these processes include transcriptional-translational feedback loops involving clock factors that regulate glycolipid metabolism. Emerging therapeutic strategies, such as pharmacological and dietary interventions, highlight the translational potential of circadian biology. This review underscores the importance of circadian rhythm maintenance for glycolipid metabolism and its role in preventing metabolic disorders. Further elucidation of the molecular mechanisms linking circadian regulation to glycolipid metabolism could pave the way for precision medicine approaches tailored to individual circadian profiles.

Molecular mechanisms of pyroptosis in non-alcoholic steatohepatitis and feasible diagnosis and treatment strategies

Pyroptosis is a distinct form of cell death that plays a critical role in intensifying inflammatory responses. It primarily occurs via the classical pathway, non-classical pathway, caspase-3/6/7/8/9-mediated pathways, and granzyme-mediated pathways. Key effector proteins involved in the pyroptosis process include gasdermin family proteins and pannexin-1 protein. Pyroptosis is intricately linked to the onset and progression of non-alcoholic steatohepatitis (NASH). During the development of NASH, factors such as pyroptosis, innate immunity, lipotoxicity, endoplasmic reticulum stress, and gut microbiota imbalance interact and interweave, collectively driving disease progression. This review analyzes the molecular mechanisms of pyroptosis and its role in the pathogenesis of NASH. Furthermore, it explores potential diagnostic and therapeutic strategies targeting pyroptosis, offering new avenues for improving the diagnosis and treatment of NASH.

Potential bidirectional communication between the liver and the central circadian clock in MASLD

Most aspects of physiology and behaviour fluctuate every 24 h in mammals. These circadian rhythms are orchestrated by an autonomous central clock located in the suprachiasmatic nuclei that coordinates the timing of cellular clocks in tissues throughout the body. The critical role of this circadian system is emphasized by increasing evidence associating disruption of circadian rhythms with diverse pathologies. Accordingly, mounting evidence suggests a bidirectional relationship where disruption of rhythms by circadian misalignment may contribute to liver diseases while liver diseases alter the central clock and circadian rhythms in other tissues. Therefore, liver pathophysiology may broadly impact the circadian system and may provide a mechanistic framework for understanding and targeting metabolic diseases and adjust metabolic setpoints.

Integrating cancer medicine into metabolic rhythms

Circadian rhythms are cell-intrinsic time-keeping mechanisms that allow organisms to adapt to 24-h environmental changes, ensuring coordinated physiological functions by aligning internal metabolic oscillations with external timing cues. Disruption of daily metabolic rhythms is associated with pathological events such as cancer development, yet the mechanisms by which perturbed metabolic rhythms contribute to tumorigenesis remain unclear. Herein we review how circadian clocks drive balanced rhythmic metabolism which in turn governs physiological functions of locomotor, immune, and neuroendocrine systems. Misaligned metabolic rhythms cause pathological states which further drive cancer initiation, progression, and metastasis. Restoring the balance of metabolic rhythms with chemical, hormonal, and behavioral interventions serves as a promising strategy for cancer therapy.

Circadian rhythm, hypoxia, and cellular senescence: From molecular mechanisms to targeted strategies

Cellular senescence precipitates a decline in physiological activities and metabolic functions, often accompanied by heightened inflammatory responses, diminished immune function, and impaired tissue and organ performance. Despite extensive research, the mechanisms underpinning cellular senescence remain incompletely elucidated. Emerging evidence implicates circadian rhythm and hypoxia as pivotal factors in cellular senescence. Circadian proteins are central to the molecular mechanism governing circadian rhythm, which regulates homeostasis throughout the body. These proteins mediate responses to hypoxic stress and influence the progression of cellular senescence, with protein Brain and muscle arnt-like 1 (BMAL1 or Arntl) playing a prominent role. Hypoxia-inducible factor-1α (HIF-1α), a key regulator of oxygen homeostasis within the cellular microenvironment, orchestrates the transcription of genes involved in various physiological processes. HIF-1α not only impacts normal circadian rhythm functions but also can induce or inhibit cellular senescence. Notably, HIF-1α may aberrantly interact with BMAL1, forming the HIF-1α-BMAL1 heterodimer, which can instigate multiple physiological dysfunctions. This heterodimer is hypothesized to modulate cellular senescence by affecting the molecular mechanism of circadian rhythm and hypoxia signaling pathways. In this review, we elucidate the intricate relationships among circadian rhythm, hypoxia, and cellular senescence. We synthesize diverse evidence to discuss their underlying mechanisms and identify novel therapeutic targets to address cellular senescence. Additionally, we discuss current challenges and suggest potential directions for future research. This work aims to deepen our understanding of the interplay between circadian rhythm, hypoxia, and cellular senescence, ultimately facilitating the development of therapeutic strategies for aging and related diseases.

Notch1 siRNA and AMD3100 Ameliorate Metabolic Dysfunction-Associated Steatotic Liver Disease

Background and Objectives: As a key mechanism of metabolic dysfunction-associated steatotic liver disease (MASLD) pathogenesis, inflammation triggered by chronic liver injury and immune cells with macrophages enables MASLD to progress to an advanced stage with irreversible processes such as fibrosis, cell necrosis, and cancer in the liver. The complexity of MASLD, including crosstalk between multiple organs and the liver, makes developing a new drug for MASLD challenging, especially in single-drug therapy. It was reported that upregulation of Notch1 is closely associated with the function of pro-inflammatory macrophages. To leverage this signaling pathway in treating MASLD, we developed a combination therapy. Materials and Methods: We chose Notch1 siRNA (siNotch1) to block the Notch pathway so that phenotypic regulation and functional recovery can be achieved in macrophages, combining with small molecule drug AMD3100. AMD3100 can cut off the migration of inflammatory cells to the liver to impede the development of inflammation and inhibit the CXCL12/CXCR4 biological axis in liver fibrosis to protect against the activation of HSCs. Then, we investigated the efficacy of the combination therapy on resolving inflammation and MASLD. Results: We demonstrated that in liver cells, siNotch1 combined with AMD3100 not only directly modulated macrophages by downregulating multiple pathways downstream of Notch, exerting anti-inflammatory, anti-migration, and switch of macrophage phenotype, but also modulated macrophage phenotypes through inhibiting NET release. The restored macrophages further regulate HSC and neutrophils. In in vivo pharmacodynamic studies, combination therapy exhibits a superior therapeutical effect over monotherapy in MASLD models. Conclusions: These results constitute an siRNA therapeutical approach combined with a small molecule drug against inflammation and liver injury in MASLD, offering a promising therapeutic intervention for MASLD.

CircaKB: a comprehensive knowledgebase of circadian genes across multiple species

Circadian rhythms, which are the natural cycles that dictate various physiological processes over a 24-h period, have been increasingly recognized as important in the management and treatment of various human diseases. However, the lack of sufficient data and reliable analysis methods have been a major obstacle to understanding the bidirectional interaction between circadian variation and human health. We have developed CircaKB, a comprehensive knowledgebase of circadian genes across multiple species. CircaKB is the first knowledgebase that provides systematic annotations of the oscillatory patterns of gene expression at a genome-wide level for 15 representative species. Currently, CircaKB contains 226 time-course transcriptome datasets, covering a wide variety of tissues, organs, and cell lines. In addition, CircaKB integrates 12 computational models to facilitate reliable data analysis and identify oscillatory patterns and their variations in gene expression. CircaKB also offers powerful functionalities to its users, including easy search, fast browsing, strong visualization, and custom upload. We believe that CircaKB will be a valuable tool and resource for the circadian research community, contributing to the identification of new targets for disease prevention and treatment. We have made CircaKB freely accessible at https://cdsic.njau.edu.cn/CircaKB.

Circadian Deregulation: Back Facing the Sun Toward Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) Development

Earth's rotation around its axis has pressured its inhabitants to adapt to 24 h cycles of day and night. Humans adapted their own circadian rhythms to the Earth's rhythms with a light-aligned awake-sleep cycle. As a consequence, metabolism undergoes drastic changes throughout the circadian cycle and needs plasticity to cope with opposing conditions in the day (when there is an increase in energy demands and food availability), and during the night (when prolonged fasting couples with cyclic changes in the energy demands across the sleep stages). In the last century, human behavior changed dramatically with a disregard for the natural circadian cycles. This misalignment in sleep and eating schedules strongly modulates the metabolism and energy homeostasis, favoring the development of obesity, metabolic syndrome, and metabolic dysfunction-associated steatotic liver disease (MASLD). This review summarizes the effects of circadian disruption, with a particular focus on the feeding and sleep cycles in the development of MASLD and hepatocellular carcinoma.

Modulation of gut microbiota by probiotics to improve the efficacy of immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma, a common malignancy of the digestive system, typically progresses through a sequence of hepatitis, liver fibrosis, cirrhosis and ultimately, tumor. The interaction between gut microbiota, the portal venous system and the biliary tract, referred to as the gut-liver axis, is crucial in understanding the mechanisms that contribute to the progression of hepatocellular carcinoma. Mechanisms implicated include gut dysbiosis, alterations in microbial metabolites and increased intestinal barrier permeability. Imbalances in gut microbiota, or dysbiosis, contributes to hepatocellular carcinoma by producing carcinogenic substances, disrupting the balance of the immune system, altering metabolic processes, and increasing intestinal barrier permeability. Concurrently, accumulating evidence suggests that gut microbiota has the ability to modulate antitumor immune responses and affect the efficacy of cancer immunotherapies. As a new and effective strategy, immunotherapy offers significant potential for managing advanced stages of hepatocellular carcinoma, with immune checkpoint inhibitors achieving significant advancements in improving patients' survival. Probiotics play a vital role in promoting health and preventing diseases by modulating metabolic processes, inflammation and immune responses. Research indicates that they are instrumental in boosting antitumor immune responses through the modulation of gut microbiota. This review is to explore the relationship between gut microbiota and the emergence of hepatocellular carcinoma, assess the contributions of probiotics to immunotherapy and outline the latest research findings, providing a safer and more cost-effective potential strategy for the prevention and management of hepatocellular carcinoma.

Konjac glucomannan Inhibits Appetite of Obese Mice by Suppressing Hypothalamic Inflammatory Response and Agrp/Npy Neuron Expression

Konjac glucomannan (KGM) is used for appetite management. However, KGM's regulation of appetite through hypothalamic neurons and gut microbiota, particularly in nonobese populations, is required to be investigated. This study investigated the differential effects of KGM on appetite and energy metabolism in obese and nonobese mice. In obese mice, KGM inhibited food intake, hypothalamic inflammation, and increased energy expenditure. Conversely, in nonobese mice, KGM maintained food intake and energy expenditure but increased hypothalamic inflammation. KGM downregulated hypothalamic Agrp, Npy, and Orx expression and upregulated Cart in obese mice, while it had no effect on orexigenic genes and downregulated Cart in nonobese mice. Additionally, KGM reshaped gut microbiota and increased Short-chain fatty acids (SCFAs) formation of obese mice, where Alistipes, Bifidobacterium, and Lactobacillus, as well as SCFAs, correlated with suppressed appetite. In nonobese mice, KGM has no significant effect on SCFAs but microbes such as Blautia, Alistipes, and Flavonifractor levels were negatively correlated with hypothalamic inflammation. KGM maintains appetite and was linked to liver-derived phosphatidylcholine, countering increased hypothalamic inflammation. The differential regulation of appetite by KGM between obese and nonobese mice is associated with hypothalamic inflammatory, neuronal, and KGM-induced personalized reshaping of gut microbiota. KGM may regulate energy intake and expenditure through the microbiota-gut-brain axis.

Sulforaphane Improves Liver Metabolism and Gut Microbiota in Circadian Rhythm Disorder Mice Models Fed With High-Fat Diets

SCOPE

This study aims to investigate the effect of sulforaphane (SFN) on hepatic metabolism and gut microbiota in a shifted circadian rhythm (CR) mouse model fed with a high-fat diet (HFD).

METHODS AND RESULTS

A shifted CR mouse model with HFD is constructed. Biochemical analyses are used to evaluate the effects of SFN on lipid accumulation and liver function. Targeted metabolomics is used for liver metabolites. Results from hematoxylin and eosin staining and Oil Red O staining show that SFN improves liver lipid accumulation and intestinal inflammatory damage in shifted CR treatment with HFD. The concentrations of amino acid metabolites are increased, and the levels of bile acid metabolites are significantly decreased by SFN treatment. Results from 16S rRNA gene sequencing indicate that SFN modulates gut microbiota, particularly by enhancing beneficial bacteria such as Lachnospiraceae, Lactobacillus, Alistipes, Akkermansia, and Eubacteriaum coprostanoligenes. Correlation analysis confirms a close relationship between intestinal microbiota and hepatic metabolites. SFN significantly regulates CR protein expression in the hypothalamus and liver tissues.

CONCLUSION

SFN alleviates hepatic metabolic disorder and gut microbiota dysbiosis induced by CR disruption under a high-fat diet in a mouse model, indicating the potential of SFN in regulating CR disruption.

Dietary Rhythms and MASLD-Related Hepatocellular Carcinoma

Dietary rhythms have emerged as a relevant variable in the equation relating nutrition and health. Both experimental and epidemiological studies point to potential beneficial effects of adequate fasting intervals between meals on the evolution of chronic diseases associated with aging. Metabolic dysfunction-associated steatotic liver disease (MASLD) is eminently related to diet and unsurprisingly, diet-based approaches are a mainstay in countering its long-term clinical evolution, including the emergence of hepatocellular carcinoma (HCC). We briefly discuss current evidence linking fasting intervals, MASLD, and HCC and propose a working hypothesis to reconcile some of the apparently conflicting results. This hypothesis relates the beneficial effects of time-restricted eating schedules to the quantity and quality of food, and it is easily amenable to testing.

Hepatic BMAL1 and HIF1α regulate a time-dependent hypoxic response and prevent hepatopulmonary-like syndrome

The transcriptional response to hypoxia is temporally regulated, yet the molecular underpinnings and physiological implications are unknown. We examined the roles of hepatic Bmal1 and Hif1α in the circadian response to hypoxia in mice. We found that the majority of the transcriptional response to hypoxia is dependent on either Bmal1 or Hif1α, through shared and distinct roles that are daytime determined. We further show that hypoxia-inducible factor (HIF)1α accumulation upon hypoxia is temporally regulated and Bmal1 dependent. Unexpectedly, mice lacking both hepatic Bmal1 and Hif1α are hypoxemic and exhibit increased mortality upon hypoxic exposure in a daytime-dependent manner. These mice display mild liver dysfunction with pulmonary vasodilation likely due to extracellular signaling regulated kinase (ERK) activation, endothelial nitric oxide synthase, and nitric oxide accumulation in lungs, suggestive of hepatopulmonary syndrome. Our findings indicate that hepatic BMAL1 and HIF1α are key time-dependent regulators of the hypoxic response and can provide molecular insights into the pathophysiology of hepatopulmonary syndrome.

Sleep-wake changes and incident depressive symptoms in midlife women

Our study aimed to investigate the relationship between sleep-wake changes and depressive symptoms events among midlife women. We enrolled 1579 women aged 44-56 years who had no clinically relevant depressive symptoms at baseline. Depressive symptoms were assessed at each visit using the Center for Epidemiologic Studies Depression scale. At the third and fourth follow-up visits, women reported their sleep habits. The sleep midpoint was defined as the time to fall asleep plus one-half of the sleep duration. Sleep-wake changes were determined by the difference in the midpoint of sleep between the third and fourth visits, which were 1 year apart. The median follow-up time was 7 years (range 1-7 years). Cox proportional hazard models were fitted to calculate hazard ratios and 95% confidence intervals for the incidence of depressive symptoms associated with sleep-wake changes. After adjusting for potential confounding factors, the hazard ratio (95% confidence interval) of depressive symptoms for severe sleep midpoint changes was 1.51 (1.12, 2.05) compared with mild sleep midpoint changes. This relationship remained statistically significant and changed little when additionally controlling for sleep duration, sleep quality, insomnia symptoms, use of sleep medications, use of nervous medications, glucose, insulin, lipids, dietary energy intake, and C-reactive protein. Our findings indicate that exposure to long-term severe sleep-wake changes increases the risk of depressive symptoms in midlife women.

Liver as a nexus of daily metabolic cross talk

Over the course of a day, the circadian clock promotes a homeostatic balance between energy intake and energy expenditure by aligning metabolism with nutrient availability. In mammals, this process is driven by central clocks in the brain that control feeding behavior, the peripheral nervous system, and humoral outputs, as well as by peripheral clocks in non-brain tissues that regulate gene expression locally. Circadian organization of metabolism is critical, as circadian disruption is associated with increased risk of metabolic disease. Emerging evidence shows that circadian metabolism hinges upon inter-organ cross talk involving the liver, a metabolic hub that integrates many facets of systemic energy homeostasis. Here, we review spatiotemporal interactions, mainly metabolite exchange, signaling factors, and hormonal control, between the liver and skeletal muscle, pancreas, gut, microbiome, and adipose tissue. Modern society presents the challenge of circadian disturbances from rotating shift work to social jet lag and 24/7 food availability. Thus, it is important to better understand the mechanisms by which the clock system controls metabolic homeostasis and work toward targeted therapies.

Diurnal control of iron responsive element containing mRNAs through iron regulatory proteins IRP1 and IRP2 is mediated by feeding rhythms

BACKGROUND

Cellular iron homeostasis is regulated by iron regulatory proteins (IRP1 and IRP2) that sense iron levels (and other metabolic cues) and modulate mRNA translation or stability via interaction with iron regulatory elements (IREs). IRP2 is viewed as the primary regulator in the liver, yet our previous datasets showing diurnal rhythms for certain IRE-containing mRNAs suggest a nuanced temporal control mechanism. The purpose of this study is to gain insights into the daily regulatory dynamics across IRE-bearing mRNAs, specific IRP involvement, and underlying systemic and cellular rhythmicity cues in mouse liver.

RESULTS

We uncover high-amplitude diurnal oscillations in the regulation of key IRE-containing transcripts in the liver, compatible with maximal IRP activity at the onset of the dark phase. Although IRP2 protein levels also exhibit some diurnal variations and peak at the light-dark transition, ribosome profiling in IRP2-deficient mice reveals that maximal repression of target mRNAs at this timepoint still occurs. We further find that diurnal regulation of IRE-containing mRNAs can continue in the absence of a functional circadian clock as long as feeding is rhythmic.

CONCLUSIONS

Our findings suggest temporally controlled redundancy in IRP activities, with IRP2 mediating regulation of IRE-containing transcripts in the light phase and redundancy, conceivably with IRP1, at dark onset. Moreover, we highlight the significance of feeding-associated signals in driving rhythmicity. Our work highlights the dynamic nature and regulatory complexity in a metabolic pathway that had previously been considered well-understood.

Biological clock regulation by the PER gene family: a new perspective on tumor development

The Period (PER) gene family is one of the core components of the circadian clock, with substantial correlations between the PER genes and cancers identified in extensive researches. Abnormal mutations in PER genes can influence cell function, metabolic activity, immunity, and therapy responses, thereby promoting the initiation and development of cancers. This ultimately results in unequal cancers progression and prognosis in patients. This leads to variable cancer progression and prognosis among patients. In-depth studies on the interactions between the PER genes and cancers can reveal novel strategies for cancer detection and treatment. In this review, we aim to provide a comprehensive overview of the latest research on the role of the PER gene family in cancer.

Autonomous circadian rhythms in the human hepatocyte regulate hepatic drug metabolism and inflammatory responses

Critical aspects of physiology and cell function exhibit self-sustained ~24-hour variations termed circadian rhythms. In the liver, circadian rhythms play fundamental roles in maintaining organ homeostasis. Here, we established and characterized an in vitro liver experimental system in which primary human hepatocytes display self-sustained oscillations. By generating gene expression profiles of these hepatocytes over time, we demonstrated that their transcriptional state is dynamic across 24 hours and identified a set of cycling genes with functions related to inflammation, drug metabolism, and energy homeostasis. We designed and tested a treatment protocol to minimize atorvastatin- and acetaminophen-induced hepatotoxicity. Last, we documented circadian-dependent induction of pro-inflammatory cytokines when triggered by LPS, IFN-β, or Plasmodium infection in human hepatocytes. Collectively, our findings emphasize that the phase of the circadian cycle has a robust impact on the efficacy and toxicity of drugs, and we provide a test bed to study the timing and magnitude of inflammatory responses over the course of infection in human liver.

Polystyrene nanoplastics inhibit beige fat function and exacerbate metabolic disorder in high-fat diet-fed mice

Global health concerns about micro- and nanoplastics are increasing. The newly discovered beige adipocytes play a vital role in energy homeostasis through their high thermogenic capacity upon activation. However, the effects of micro- and nanoplastics on beige adipocytes have not yet been studied. We investigated whether the effects of oral exposure to polystyrene nanoparticles (PS-NPs) on systemic metabolic performance can be induced by disrupting beige adipocyte function, and the potential mechanism. In the present study, C57BL/6J male mice were fed a high-fat diet (HFD) with or without PS-NPs exposure for 12 weeks to investigate the differences in metabolic performance. We also isolated stromal vascular fraction from C57BL/6J male mice to differentiate and prepare primary beige adipocyte cultures. Primary beige adipocytes were treated with PS-NPs on the sixth day of differentiation. The results showed that oral intake of PS-NPs exacerbated metabolic disorders of mice under HFD, including suppressed energy expenditure, increased fat mass and liver steatosis, decreased insulin sensitivity, disrupted glucose homeostasis, and decreased cold-tolerance capability compared with the control group. Intriguingly, we observed that, after a 12-week exposure, PS-NPs accumulated in the inguinal white adipose tissue (iWAT), a fat depot rich in beige adipocytes, further suppressing thermogenic gene programs, particularly the level of uncoupling protein 1 (UCP1), a master regulator in the browning process of beige adipocytes. These effects ultimately led to decreased energy expenditure and subsequent disorders of glucolipid metabolism. Mechanistically, we revealed that PS-NPs disrupt mitochondrial function and induce oxidative damage and inflammation in beige adipocytes to inhibit their function. These negative metabolic effects of PS-NPs were ameliorated by antioxidant supplementation. Our study is the first to demonstrate that PS-NPs exposure exacerbates metabolic disorder in HFD-fed mice by disrupting beige adipocyte function.

Circadian Rhythms in Cardiovascular Metabolism

Energetic demand and nutrient supply fluctuate as a function of time-of-day, in alignment with sleep-wake and fasting-feeding cycles. These daily rhythms are mirrored by 24-hour oscillations in numerous cardiovascular functional parameters, including blood pressure, heart rate, and myocardial contractility. It is, therefore, not surprising that metabolic processes also fluctuate over the course of the day, to ensure temporal needs for ATP, building blocks, and metabolism-based signaling molecules are met. What has become increasingly clear is that in addition to classic signal-response coupling (termed reactionary mechanisms), cardiovascular-relevant cells use autonomous circadian clocks to temporally orchestrate metabolic pathways in preparation for predicted stimuli/stresses (termed anticipatory mechanisms). Here, we review current knowledge regarding circadian regulation of metabolism, how metabolic rhythms are synchronized with cardiovascular function, and whether circadian misalignment/disruption of metabolic processes contribute toward the pathogenesis of cardiovascular disease.

Effects of exercise on circadian rhythms in humans

The biological clock system is an intrinsic timekeeping device that integrates internal physiology and external cues. Maintaining a healthy biological clock system is crucial for life. Disruptions to the body's internal clock can lead to disturbances in the sleep-wake cycle and abnormalities in hormone regulation, blood pressure, heart rate, and other vital processes. Long-term disturbances have been linked to the development of various common major diseases, including cardiovascular diseases, metabolic disorders, tumors, neuropsychiatric conditions, and so on. External factors, such as the diurnal rhythm of light, have a significant impact on the body's internal clock. Additionally, as an important non-photic zeitgeber, exercise can regulate the body's internal rhythms to a certain extent, making it possible to become a non-drug intervention for preventing and treating circadian rhythm disorders. This comprehensive review encompasses behavioral, physiological, and molecular perspectives to provide a deeper understanding of how exercise influences circadian rhythms and its association with related diseases.

Utilization of Food-Derived β-Glucans to Prevent and Treat Non-Alcoholic Fatty Liver Disease (NAFLD)

Non-alcoholic fatty liver disease (NAFLD) has become the most common chronic liver disease nowadays. Currently, there is no officially approved drug to treat NAFLD. In view of the increasing global prevalence of NAFLD and an absence of treatments, the development of effective treatments is of utmost importance. β-glucan, a natural bioactive polysaccharide, has demonstrated hepatoprotective effects in NAFLD prevention and treatment. This review solely focuses on gathering the published preclinical animal studies that demonstrated the anti-liver injury, anti-steatotic, anti-inflammatory, anti-fibrotic, and antioxidant activities of β-glucan. The impact of β-glucan on gut microbiota and its metabolites including short-chain fatty acids and bile acids as the underlying mechanism for its bioactive beneficial effect on NAFLD is also explored. Given the limited knowledge of β-glucan on anti-fibrotic activity, bile acid metabolism, and gut microbiota function, additional relevant research is highly encouraged to lay a solid foundation for the use of food-derived β-glucan as a functional food for NAFLD. It is envisaged that further investigation of food-derived β-glucan in human clinical studies should be carried out for its wider utilization.