Atlas of exercise metabolism reveals time-dependent signatures of metabolic homeostasis

Serum metabolic fingerprints encode functional biomarkers for ovarian cancer diagnosis: a large-scale cohort study

BACKGROUND

Ovarian cancer (OC) ranks as the most lethal gynaecological malignancy worldwide, with early diagnosis being crucial yet challenging. Current diagnostic methods like transvaginal ultrasound and blood biomarkers show limited sensitivity/specificity. This study aimed to identify and validate serum metabolic biomarkers for OC diagnosis using the largest cohort reported to date.

METHODS

We constructed a large-scale OC-associated cohort of 1432 subjects, including 662 OC, 563 benign ovarian disease, and 207 healthy control subjects, across retrospective (n = 1073) and set-aside validation (n = 359) cohorts. Serum metabolic fingerprints (SMFs) were recorded using nanoparticle-enhanced laser desorption/ionization mass spectrometry (NELDI-MS). A diagnostic panel was developed through machine learning of SMFs in the discovery cohort and validated in independent verification and set-aside validation cohorts. The identified metabolic biomarkers were further validated using liquid chromatography MS and their biological functions were assessed in OC cell lines.

FINDINGS

We identified a metabolic biomarker panel including glucose, histidine, pyrrole-2-carboxylic acid, and dihydrothymine. This panel achieved consistent areas under the curve (AUCs) of 0.87-0.89 for distinguishing between malignant and benign ovarian masses across all cohorts, and improved to AUCs of 0.95-0.99 when combined with risk of ovarian malignancy algorithm (ROMA). In vitro validation provided initial biological context for the metabolic alterations observed in our diagnostic panel.

INTERPRETATION

Our study established a reliable serum metabolic biomarker panel for OC diagnosis with potential clinical translations. The NELDI-MS based approach offers advantages of fast analytical speed (∼30 s/sample) and low cost (∼2-3 dollars/sample), making it suitable for large-scale clinical applications.

FUNDING

MOST (2021YFA0910100), NSFC (82421001, 823B2050, 824B2059, and 82173077), Medical-Engineering Joint Funds of Shanghai Jiao Tong University (YG2021GD02, YG2024ZD07, and YG2023ZD08), Shanghai Science and Technology Committee Project (23JC1403000), Shanghai Institutions of Higher Learning (2021-01-07-00-02-E00083), Shanghai Jiao Tong University Inner Mongolia Research Institute (2022XYJG0001-01-16), Sichuan Provincial Department of Science and Technology (2024YFHZ0176), Innovation Research Plan by the Shanghai Municipal Education Commission (ZXWF082101), Innovative Research Team of High-Level Local Universities in Shanghai (SHSMU-ZDCX20210700), Basic-Clinical Collaborative Innovation Project from Shanghai Immune Therapy Institute, Guangdong Basic and Applied Basic Research Foundation (2024A1515013255).

Enhanced metabolic adaptations following late dark phase wheel running in high-fat diet-fed mice

Exercise interventions represent an effective strategy to prevent and treat metabolic diseases and the time-of-day-dependent effects of exercise on metabolic outcomes are becoming increasingly apparent. We aimed to study the influence of time-restricted wheel running on whole-body energy and glucose homeostasis. Male, 8-week-old, C57BL/6NTac mice were fed either a 60% high-fat diet (HFD) or a 10% low-fat diet (LFD) for 4 weeks. Following this, mice were given access to a running wheel between zeitgeber time (ZT) 12-16 (early dark phase) or ZT 20-0 (late dark phase). Sedentary mice had access to a permanently locked wheel. Mice were housed under these conditions in metabolic chambers for 4 weeks in which LFD and HFD conditions were maintained. Following the exercise intervention, body composition and glucose tolerance were assessed. Wheel running during either the early or late dark phase resulted in metabolic improvements such as attenuation in body weight gain, enhanced glucose tolerance and reduced ectopic lipid deposition. However, late dark phase exercise resulted in a greater reduction in body weight gain, as well as enhanced metabolic flexibility and insulin sensitivity. Our data suggest that late dark phase versus early dark phase exercise confers greater metabolic adaptations in HFD-fed mice.

Constitutively active mTORC1 signaling modifies the skeletal muscle metabolome and lipidome response to exercise

A chronic increase in the Mammalian Target of Rapamycin Complex 1 (mTORC1) signaling is implicated in reduced longevity, altered metabolism, and mitochondrial dysfunction. Abnormal mTORC1 signaling may also be involved in the etiology of sarcopenia. To better understand the role of mTORC1 signaling in the regulation of muscle metabolism, we developed an inducible muscle-specific knockout model of DEP domain-containing 5 protein (DEPDC5 mKO), which results in constitutively active mTORC1 signaling. We hypothesized that constitutively active mTORC1 signaling in skeletal muscle would alter the metabolomic and lipidomic response to an acute bout of exercise. Wild-type (WT) and DEPDC5 muscle-specific knockout (KO) mice were studied at rest and following a 1 h bout of treadmill exercise. Acute exercise induced an increased reliance on glycolytic and pentose phosphate pathway (PPP) metabolites in the muscle of mice with hyperactive mTORC1. Lipidomic analysis showed an increase in triglycerides (TGs) in KO mice. Although exercise had a pronounced effect on muscle metabolism, the genotype effect was larger, indicating that constitutively active mTORC1 signaling exerts a dominant influence on metabolic and lipidomic regulation. We conclude that increased mTORC1 signaling shifts muscle metabolism toward greater reliance on nonoxidative energy sources in response to exercise. Understanding the mechanisms responsible for these effects may lead to the development of strategies for restoring proper mTORC1 signaling in conditions such as aging and sarcopenia.NEW & NOTEWORTHY This study demonstrates that hyperactive mTORC1 alters the muscle metabolomic and lipidomic response to exercise, with genotype having a larger effect than exercise. Knockout mice exhibited an increase in reliance on glycolysis and pentose phosphate pathway and an increase in triglyceride turnover. Wild-type mice primarily showed an increase in utilization of TCA cycle and lipid metabolism intermediates.

Muscle-Derived Small Extracellular Vesicles Mediate Exercise-Induced Cognitive Protection in Chronic Cerebral Hypoperfusion

Physical exercise protects against cognitive impairment caused by chronic cerebral hypoperfusion (CCH). However, the mechanisms through which exercise sends signals from the periphery to the central nervous system remain incompletely understood. This study demonstrated that exercise promotes the secretion of muscle-derived small extracellular vesicles (sEVs), which facilitate interorgan communication between the muscle and the brain. Systematic delivery of muscle-derived sEVs enhances synaptic plasticity and alleviated cognitive impairment in CCH. Notably, miRNA sequencing reveal miR-17/20a-5p as key cargos in sEVs involved in the exercise-induced muscle-brain crosstalk. Muscle-derived sEVs are also identified as the primary source of swimming-induced miR-17/20a-5p in circulating sEVs. Mechanistically, miR-17/20a-5p binds to the DEP-domain containing mTOR-interacting protein (DEPTOR) and activates the mammalian target of rapamycin (mTOR) pathway in the hippocampus. Depletion of miR-17/20a-5p from muscle-derived sEVs impairs the exercise-induced enhancement of synaptic plasticity and cognitive function. Moreover, overexpression of DEPTOR in the hippocampus attenuates the cognitive benefits of exercise. Conversely, hippocampus-specific activation of mTOR reverses these effects, highlighting the crucial role of mTOR in mediating the positive effects of exercise. Collectively, these findings identify miR-17/20a-5p in muscle-derived sEVs as the exercise-induced myokine with potent effects on the brain, emphasizing the therapeutic potential of exercise in managing cognitive impairment.

Morning vs. evening: the role of exercise timing in enhancing fat oxidation in young men

Objective

This study aimed to investigate the acute effects of exercise timing (morning vs. evening) on fat oxidation and energy expenditure in young men, with a focus on interactions between exercise and meal timing.

Methods

Eighteen male college students (23.47 ± 2.11 years) completed a randomized crossover trial under five conditions: sedentary control (SC), exercise before breakfast (EBB), exercise after breakfast (EAB), exercise before dinner (EBD), and exercise after dinner (EAD). Indirect calorimetry (COSMED K5) measured substrate utilization during exercise, post-exercise recovery (0-4 h), and the following morning. Total exercise volume (running distance) was standardized, and energy expenditure was normalized to body weight (kcal/kg).

Results

During the sedentary control test, participants showed similar trends in total energy expenditure. Dring exercise, the EBB group demonstrated significantly higher fat expenditure compared to EAB (P < 0.05), EBD (P < 0.01), and EAD (P < 0.01). Morning exercise overall exhibited superior fat oxidation (P < 0.01). Post-exercise (0-4 h), EBB sustained elevated fat utilization (P < 0.01 vs. EBD/EAD), while EAD showed enhanced fat oxidation the following morning (P < 0.01 vs. EAB).

Conclusion

The findings suggest that exercise timing may influence temporal patterns of fat oxidation, with morning fasting potentially favoring acute lipid utilization, while evening exercise appears to correlate with delayed metabolic adjustments. Although total energy expenditure remained comparable across conditions, the observed shifts in substrate allocation imply a possible circadian-sensitive modulation of energy partitioning. These preliminary observations underscore the need for further investigation to clarify the long-term physiological relevance of such timing-dependent metabolic responses.

Ambient PM2.5 exposure, physical activity, and cardiovascular dysfunction: Analysis of CHARLS data and experimental study in mice

Previous studies have confirmed ambient fine particulate matter (PM2.5) as a major environmental risk factor for cardiovascular diseases (CVDs), yet the specific molecular pathways remain poorly understood. Furthermore, while physical activity benefits cardiovascular health, its protective effects against PM2.5-induced damage need further explored. We aimed to investigate the relationship between long-term PM2.5 exposure, physical activity, and cardiovascular health, and explore the potential molecular mechanisms. This research combined epidemiological and experimental approaches. The epidemiological study analyzed data from the China Health and Retirement Longitudinal Study (CHARLS) to investigate the associations among long-term PM2.5 exposure, physical activity, and CVDs. For the experimental study, C57BL/6 male mice were assigned to either regular physical activity or sedentary behavior, and were exposed to PM2.5 or filtered air (FA) for 2, 4, and 6 months. We observed that long-term PM2.5 exposure significantly increased cardiovascular disease risk, while physical activity exhibited protective effects and can partially mitigate the adverse impacts of PM2.5 on heart disease and dyslipidemia. In animal study, mice with long-term exposure to PM2.5 demonstrated elevated blood pressure, disrupted adipokine levels, altered lipid profiles, and mitochondrial damage. Regular physical activity partially mitigated these adverse effects. Lipidomics and proteomics analyses revealed that PM2.5 exposure disrupted lipid metabolism networks and protein regulatory pathways, while regular physical activity mitigated these perturbations through the modulation of lipid metabolism, the coagulation cascade, and immune responses. These findings underscore the importance of regular physical activity in public health strategies, while prioritizing PM2.5 reduction measures for cardiovascular disease prevention.

Endurance Exercise Training Alleviates Hepatic Lipocalin-2 Release and Prevents Anxiety-Like Disorders in Chronically Stressed Mice

Exercise training can prevent anxiety disorders in both rodent models and human cohorts. The involvement of peripheral factors in exercise-mediated mental health is being appreciated. It is recently shown that the hepatic biosynthesis of lipocalin-2 (LCN2) can respond to chronic restraint stress (CRS) and elicit anxiety-like behaviors via inhibiting the neural activity in the medial prefrontal cortex (mPFC). Here, it is found that 14-day treadmill exercise training ameliorates anxiety-like behaviors in these CRS-treated mice. Further assays show that exercise intervention reduces the hepatic release of LCN2. Meanwhile, exercise training may also counteract the adverse effect of LCN2 via relieving the cortical microglial cell proliferation. The results collectively suggest that exercise training may modulate the liver-brain axis to reshape the cortical activity for preventing anxiety disorders.

PoWeR elicits intracellular signaling, mitochondrial adaptations, and hypertrophy in multiple muscles consistent with endurance and resistance exercise training

Physical activity guidelines recommend both endurance and resistance exercise to improve and maintain overall health. Recently, progressive weighted wheel running (PoWeR), a voluntary, progressive, and high-volume exercise paradigm, was posited as a singular prototype of combined endurance and resistance exercise in mice as evident by enhanced capillarization and hypertrophy of select plantar flexor muscles. Despite growing interest in this model, it remains incompletely characterized if PoWeR resembles the acute and chronic responses to resistance and/or endurance exercise in humans. Therefore, the purpose of this study was to assess canonical signaling events, mitochondrial bioenergetics, and cellular adaptations across multiple extensor and flexor muscles of the fore- and hindlimbs that may be conducive for whole-body functional improvements as traditionally observed in humans. Eight weeks of PoWeR (∼8 km/day) improved glucose metabolism, exercise capacity, body composition, and bone mineral density as well as increased mass, myofiber cross-sectional area (CSA), and oxidative myofiber type distribution in the soleus, plantaris, and flexor digitorum longus (FDL). Using two ex vivo high-resolution fluororespirometry protocols that model in vivo physiological conditions, PoWeR decreased mitochondrial ADP sensitivity which was accompanied by greater mitochondrial H2O2 emissions, respiration, conductance, and protein content in the vastus lateralis, gastrocnemius, and triceps in muscle-specific fashion. Three days of short-term PoWeR stimulated mTOR complex 1 (mTORC1) and AMP activated protein kinase (AMPK) signaling in soleus, plantaris, and/or FDL in line with the hypertrophic and metabolic adaptations observed with long-term training. Collectively, these data support PoWeR as a suitable paradigm in mice to model the acute signaling and chronic adaptations associated with endurance and resistance exercise in humans.NEW & NOTEWORTHY Using PoWeR, we evaluated skeletal muscle mitochondrial and hypertrophic adaptions revealing muscle-specific adaptations across fore and hind limbs consistent with endurance and resistance exercise in humans. We present a short-term PoWeR paradigm that identifies muscle-specific signaling responses thought to support long-term adaptions to PoWeR. These data provide further support for PoWeR as a model to resemble the metabolic and anabolic adaptions to endurance and resistance exercise in humans.

Glucose metabolism in the perfused liver did not improve with resistance training in male Swiss mice under caloric restriction

CONTEXT

Energy homeostasis is a primary factor for the survival of mammals. Many tissues and organs, among which is the liver, keep this homeostasis in varied circumstances, including caloric restriction (CR) and physical activity.

OBJECTIVE

This study investigated glucose metabolism using the following groups of eight-week-old male Swiss mice: CS, sedentary and fed freely; RS, sedentary and RT, trained, both under 30% CR (n = 20-23 per group).

RESULTS

Organs and fat depots of groups RS and RT were similar to CS, although body weight was lower. CR did not impair training performance nor affected systemic or hepatic glucose metabolism. Training combined with CR (group RT) improved in vivo glucose tolerance and did not affect liver gluconeogenesis.

CONCLUSIONS

The mice tolerated the prolonged moderate CR without impairment of their well-being, glucose homeostasis, and resistance training performance. But the higher liver gluconeogenic efficiency previously demonstrated using this training protocol in mice was not evidenced under CR.

Ergothioneine controls mitochondrial function and exercise performance via direct activation of MPST

Ergothioneine (EGT) is a diet-derived, atypical amino acid that accumulates to high levels in human tissues. Reduced EGT levels have been linked to age-related disorders, including neurodegenerative and cardiovascular diseases, while EGT supplementation is protective in a broad range of disease and aging models. Despite these promising data, the direct and physiologically relevant molecular target of EGT has remained elusive. Here, we use a systematic approach to identify how mitochondria remodel their metabolome in response to exercise training. From these data, we find that EGT accumulates in muscle mitochondria upon exercise training. Proteome-wide thermal stability studies identify 3-mercaptopyruvate sulfurtransferase (MPST) as a direct molecular target of EGT; EGT binds to and activates MPST, thereby boosting mitochondrial respiration and exercise training performance in mice. Together, these data identify the first physiologically relevant EGT target and establish the EGT-MPST axis as a molecular mechanism for regulating mitochondrial function and exercise performance.

Configural path of obesity: linkage of physical activity and lifestyle based on fuzzy-set qualitative comparative analysis

Obesity plays a significant role in the burden of various health conditions, it is not only a global health issue but challenges the national public health system. Some regions of China still face a high prevalence of obesity, and it is broadly recognized that physical activities interact with lifestyle in different pathways would affect obesity. We aim to capture different configurational paths that lead to obesity, using the fuzzy set Qualitative Comparative Analysis. Eight obesity-related variables were involved, and data were collected between January 1, 2021, and January 31, 2022. The study shows six configurational paths result in obesity, in which the necessary condition is "educational status," and core conditions of "the time of exercise" and "weekly sitting time*sleeping time less than 6 h*second hand smoking exposure on average of 4-6 days per week *keep excising on average of 4 times per week* exercise intensity on the shortness of breath, markedly increased heart rate, heavy sweating" play an important role in the obesity outcome, and the solution exhibits acceptable consistency is 0.50. The six configurational paths solution consistency is 0.76, and the solution coverage is 0.31. Besides the necessary condition and core factors that play(s) an important role in the development of obesity, we have to consider the multiple factors of physical activity and lifestyle have a cross-cutting effect on obesity. This can offer a better understanding of the mechanisms that cause obesity by identifying and characterizing the regional population, which would help develop an effective protective measure for obesity.

Dietary timing enhances exercise by modulating fat-muscle crosstalk via adipocyte AMPKα2 signaling

Feeding rhythms regulate exercise performance and muscle energy metabolism. However, the mechanisms regulating adipocyte functions remain unclear. Here, using multi-omics analyses, involving (phospho-)proteomics and lipidomics, we found that day-restricted feeding (DRF) regulates diurnal rhythms of the mitochondrial proteome, neutral lipidome, and nutrient-sensing pathways in mouse gonadal white adipose tissue (GWAT). Adipocyte-specific knockdown of Prkaa2 (the gene encoding AMPKα2) impairs physical endurance. This defect is associated with altered rhythmicity in acyl-coenzyme A (CoA) metabolism-related genes, a loss of rhythmicity in the GWAT lipidome, and circadian remodeling of serum metabolites-in particular, lactate and succinate. We also found that adipocyte Prkaa2 regulates muscle clock genes during DRF. Notably, oral administration of the AMPK activator C29 increases endurance and muscle functions in a time-of-day manner, which requires intact adipocyte AMPKα2 signaling. Collectively, our work defines adipocyte AMPKα2 signaling as a critical regulator of circadian metabolic coordination between fat and muscle, thereby enhancing exercise performance.

Timing of exercise differentially impacts adipose tissue gain in male adolescent rats

OBJECTIVE

Circadian rhythms of metabolic, hormonal, and behavioral fluctuations and their alterations can impact health. An important gap in knowledge in the field is whether the time of the day of exercise and the age of onset of exercise exert distinct effects at the level of whole-body adipose tissue and body composition. The goal of the present study was to determine how exercise at different times of the day during adolescence impacts the adipose tissue transcriptome and content in a rodent model.

METHODS

Rats were subjected to one of four conditions during their adolescence: early active phase control or exercise (EAC or EAE; ZT13), and late active phase control or exercise (LAC or LAE; ZT23). The effects of exercise timing were assessed at the level of subcutaneous and visceral adipose tissue transcriptome, body composition, hypothalamic expression of orexigenic and anorexigenic genes, blood serum markers and 24-hour core body temperature patterns.

RESULTS

We found that late active phase exercise (ZT23) greatly upregulated pathways of lipid synthesis, glycolysis and NADH shuttles in LAE rats, compared to LAC or EAE. Conversely, LAE rats showed notably lower content of adipose tissue. In addition, LAE rats showed signs of impaired FGF21-adiponectin axis compared to other groups.

CONCLUSIONS

Finally, LAE rats showed higher post-exercise core body temperature compared to other groups. Our results thus indicate that our exercise protocol induced an unusual effect characterized by enhanced lipid synthesis but reduced adipose tissue content in late active phase but not early active phase exercise during adolescence.

Diurnal variation in skeletal muscle mitochondrial function dictates time-of-day-dependent exercise capacity

Exercise impinges on almost all physiological processes at an organismal level and is a potent intervention to treat various diseases. Exercise performance is well established to display diurnal rhythm, peaking during the late active phase. However, the underlying molecular/metabolic factors and mitochondrial energetics that possibly dictate time-of-day exercise capacity remain unknown. Here, we have unraveled the importance of diurnal variation in mitochondrial functions as a determinant of skeletal muscle exercise performance. Our results show that exercise-induced muscle metabolome and mitochondrial energetics are distinct at ZT3 and ZT15. Importantly, we have elucidated key diurnal differences in mitochondrial functions that are well correlated with disparate time-of-day-dependent exercise capacity. Providing causal mechanistic evidence, we illustrate that loss of Sirtuin4 (SIRT4), a well-known mitochondrial regulator, abrogates mitochondrial diurnal variation and consequently abolishes time-of-day-dependent muscle output. Therefore, our findings unequivocally demonstrate the pivotal role of baseline skeletal muscle mitochondrial functions in dictating diurnal exercise capacity.

Exploration of Novel Metabolic Mechanisms Underlying Primary Biliary Cholangitis Using Hepatic Metabolomics, Lipidomics, and Proteomics Analysis

Metabolic reprogramming is important in primary biliary cholangitis (PBC) development. However, studies investigating the metabolic signature within the liver of PBC patients are limited. In this study, liver biopsies from 31 PBC patients and 15 healthy controls were collected, and comprehensive metabolomics, lipidomics, and proteomics analysis were conducted to characterize the metabolic landscape in PBC. We observed distinct lipidome remodeling in PBC with increased polyunsaturated fatty acid levels and augmented fatty acid β-oxidation (FAO), evidenced by the increased acylcarnitine levels and upregulated expression of proteins involved in FAO. Notably, PBC patients exhibited an increase in glucose-6-phosphate (G6P) and purines, alongside a reduction in pyruvate, suggesting impaired glycolysis and increased purines biosynthesis in PBC. Additionally, the accumulation of bile acids as well as a decrease in branched chain amino acids and aromatic amino acids were observed in PBC liver. We also observed an aberrant upregulation of proteins associated with ductular reaction, apoptosis, and autophagy. In conclusion, our study highlighted substantial metabolic reprogramming in glycolysis, fatty acid metabolism, and purine biosynthesis, coupled with aberrant upregulation of proteins associated with apoptosis and autophagy in PBC patients. Targeting the specific metabolic reprogramming may offer potential targets for the therapeutic intervention of PBC.

Circadian biology of cardiac aging

The age of the U.S. population is increasing alongside a growing burden of age-related cardiovascular disease. Circadian rhythms are critical for human health and are disrupted with aging and cardiovascular disease. The goal of the present review is to summarize how cardiac circadian rhythms change with age and how this might contribute to the increasing burden of age-associated heart disease. Further, we will review what is known about interventions to slow aging and whether they impact cardiac clock function, as well as whether time-of-day or chronotherapy may improve cardiac function with age. Although much remains to be understood about the circadian biology of cardiac aging, we propose that altered circadian clock output should be considered a hallmark of aging and that efforts to fix the clock are warranted for healthy cardiac aging.

The association of activity patterns on female reproductive diseases: a prospective cohort study of UK biobank

OBJECTIVE

Little is known about the role of timing of physical activity in female reproductive disorders. These disorders include polycystic ovary syndrome (PCOS), heavy menstrual bleeding (HMB), endometriosis, infertility, and pregnancy-related disorders. This study aims to investigate the associations of activity patterns with female reproductive diseases.

METHODS

A total of 49,540 female participants from the UK Biobank with valid accelerometer data were enrolled at baseline. Activity patterns were defined based on the timing of moderate-to-vigorous intensity physical activity (MVPA) throughout the day. Participants were categorized into four groups according to the timing of their MVPA: "morning, evening, mixed, midday-afternoon", with the midday-afternoon group serving as the reference. Cox proportional hazards models were utilized to evaluate the association between activity patterns and female reproductive diseases.

RESULTS

During a median follow-up of 12.6 years, a total of 1044 cases of female reproductive diseases were documented. After adjustment for potential confounders, compared to women with midday-afternoon exercise, women with morning exercise and mixed-timing exercise were associated with lower risks for female reproductive diseases (HRmorning=0.81, 95% CI: 0.67-0.98; HRmixed=0.79, 95% CI: 0.69-0.91, P-trend < 0.05). Moreover, morning exercise and mixed-timing exercise had lower risks of PCOS (HRmorning=0.38, 95% CI: 0.15-0.97; HRmixed=0.27, 95% CI: 0.13-0.57, P-trend<0.001), and mixed-timing exercise was associated with a lower risk for HMB (HRmixed=0.81, 95% CI: 0.70-0.95, P-trend < 0.05), compared with the reference group.

CONCLUSIONS

Compared with midday-afternoon group, morning and mixed MVPA timing groups, but not evening group, were associated with decreased risks for female reproductive diseases and PCOS. In addition, we found that women with mixed MVPA timing exercise had a lower risk of HMB, compared with the reference group.

Integral-Omics: Serial Extraction and Profiling of Metabolome, Lipidome, Genome, Transcriptome, Whole Proteome and Phosphoproteome Using Biopsy Tissue

The integrative multiomics characterization of minute amounts of clinical tissue specimens has become increasingly important. Here, we present an approach called Integral-Omics, which enables sequential extraction of metabolites, lipids, genomic DNA, total RNA, proteins, and phosphopeptides from a single biopsy-level tissue specimen. We benchmarked this method with various samples, applied the workflow to perform multiomics profiling of tissues from six patients with colorectal cancer, and found that tumor tissues exhibited suppressed ferroptosis pathways at multiomics levels. Together, this study presents a methodology that enables sequential extraction and profiling of metabolomics, lipidomics, genomics, transcriptomics, proteomics, and phosphoproteomics using biopsy tissue specimens.

Acute exercise promotes WAT browning by remodeling mRNA m6A methylation

AIMS

Regular exercise promotes the beiging and metabolic adaptations of white adipose tissue (WAT) through the cumulative transcriptional responses that occur after each exercise session. However, the effects of a single bout of acute exercise and the role of N6-methyladenosine (m6A) in these adaptations remain unclear. We aim to investigate this further.

MATERIALS AND METHODS

We constructed mouse models for chronic (8 weeks of running) and acute (single 1-hour run) exercise to study the effects on white adipose tissue (WAT) metabolism and beiging through metabolic phenotyping and transcriptome sequencing. Additionally, we explored the impact of acute exercise on WAT m6A modification and target genes, combining m6A regulators with cell models to elucidate the role of m6A in WAT exercise adaptation.

KEY FINDINGS

Here, we reveal that upregulated m6A modification after acute exercise induces the formation of glycolytic beige fat (g-beige fat) in WAT. Mechanistically, the metabolite β-hydroxybutyrate (BHBA) secreted after acute exercise upregulates m6A modification in WAT. This enhances m6A-dependent translation of the histone acetyltransferase CREBBP, promoting the transcription of key beiging genes by increasing chromatin accessibility. Pharmacologically elevating circulating BHBA mimics the metabolic response induced by acute exercise, upregulating m6A modification and its downstream signals. Additionally, BHBA exhibits long-term effects, improving metabolic homeostasis in obesity by promoting thermogenesis in WAT.

SIGNIFICANCE

Our results reveal the role of metabolites in WAT metabolic adaptation through m6A-mediated chromatin accessibility after acute exercise, providing a novel therapeutic target for regulating WAT metabolism from a nutritional epigenetics perspective.

Effects of time-of-day on the noradrenaline, adrenaline, cortisol and blood lipidome response to an ice bath

While the effect of time-of-day (morning versus evening) on hormones, lipids and lipolysis has been studied in relation to meals and exercise, there are no studies that have investigated the effects of time-of-day on ice bath induced hormone and lipidome responses. In this crossover-designed study, a group of six women and six men, 26 ± 5 years old, 176 ± 7 cm tall, weighing 75 ± 10 kg, and a BMI of 23 ± 2 kg/m2 had an ice bath (8-12 °C for 5 min) both in the morning and evening on separate days. Absence from intense physical exercise, nutrient intake and meal order was standardized in the 24 h prior the ice baths to account for confounders such as diet or exercise. We collected venous blood samples before and after (5 min and 30 min) the ice baths to measure hormones (noradrenaline, adrenaline, and cortisol) and lipid levels in plasma via liquid chromatography mass spectrometry shotgun lipidomics. We found that ice baths in the morning increase plasma fatty acids more than in the evening. Overall plasma lipid composition significantly differed in-between the morning and evening, and only in the morning ice bathing is accompanied by significantly increased plasma fatty acids from 5.1 ± 2.2% to 6.0 ± 2.4% (P = 0.029) 5 min after and to 6.3 ± 3.1% (P = 0.008) 30 min after. Noradrenaline was not affected by time-of-day and increased significantly immediately after the ice baths in the morning by 127 ± 2% (pre: 395 ± 158 pg/ml, post 5 min: 896 ± 562 pg/ml, P = 0.025) and in the evening by 144 ± 2% (pre: 385 ± 146 pg/ml, post 5 min: 937 ± 547 pg/ml, P = 0.015). Cortisol was generally higher in the morning than in the evening (pre: 179 ± 108 pg/ml versus 91 ± 59 pg/ml, P = 0.013; post 5 min: 222 ± 96 pg/ml versus 101 ± 52 pg/ml, P = 0.001; post 30 min: 190 ± 96 pg/ml versus 98 ± 54 pg/ml, P = 0.009). There was no difference in the hormonal and lipidome response to an ice bath between women and men. The main finding of the study was that noradrenaline, adrenaline, cortisol and plasma lipidome responses are similar after an ice bath in the morning and evening. However, ice baths in the morning increase plasma fatty acids more than in the evening.

Sexual dimorphism on the acute effect of exercise in the morning vs. evening: A randomized crossover study

BACKGROUND

Mammalian cells possess molecular clocks, the adequate functioning of which is decisive for metabolic health. Exercise is known to modulate these clocks, potentially having distinct effects on metabolism depending on the time of day. This study aimed to investigate the impact of morning vs. evening moderate-intensity aerobic exercise on glucose regulation and energy metabolism in healthy men and women. It also aimed to elucidate molecular mechanisms within skeletal muscle.

METHODS

Using a randomized crossover design, healthy men (n = 18) and women (n = 17) performed a 60-min bout of moderate-intensity aerobic exercise in the morning and evening. Glucose regulation was continuously monitored starting 24 h prior to the exercise day and continuing until 48 h post-exercise for each experimental condition. Energy expenditure and substrate oxidation were measured by indirect calorimetry during exercise and at rest before and after exercise for 30 min. Skeletal muscle biopsies were collected immediately before and after exercise to assess mitochondrial function, transcriptome, and mitochondrial proteome.

RESULTS

Results indicated similar systemic glucose, energy expenditure, and substrate oxidation during and after exercise in both sexes. Notably, transcriptional analysis, mitochondrial function, and mitochondrial proteomics revealed marked sexual dimorphism and time of day variations.

CONCLUSION

The sexual dimorphism and time of day variations observed in the skeletal muscle in response to exercise may translate into observable systemic effects with higher exercise-intensity or chronic exercise interventions. This study provides a foundational molecular framework for precise exercise prescription in the clinical setting.

Quantification of nutrient fluxes during acute exercise in mice

Despite the known metabolic benefits of exercise, an integrated metabolic understanding of exercise is lacking. Here, we use in vivo steady-state isotope-labeled infusions to quantify fuel flux and oxidation during exercise in fasted, fed, and exhausted female mice, revealing several novel findings. Exercise strongly promoted glucose fluxes from liver glycogen, lactate, and glycerol, distinct from humans. Several organs spared glucose, a process that broke down in exhausted mice despite concomitant hypoglycemia. Proteolysis increased markedly, also divergent from humans. Fatty acid oxidation dominated during fasted exercise. Ketone production and oxidation rose rapidly, seemingly driven by a hepatic bottleneck caused by gluconeogenesis-induced cataplerotic stress. Altered fuel consumption was observed in organs not directly involved in muscle contraction, including the pancreas and brown fat. Several futile cycles surprisingly persisted during exercise, despite their energy cost. In sum, we provide a comprehensive, integrated, holistic, and quantitative accounting of metabolism during exercise in an intact organism.

Grape-Seed Proanthocyanidin Extract (GSPE) Modulates Diurnal Rhythms of Hepatic Metabolic Genes and Metabolites, and Reduces Lipid Deposition in Cafeteria-Fed Rats in a Time-of-Day-Dependent Manner

SCOPE

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a global health issue with increasing prevalence. Polyphenols, such as grape seed proanthocyanidin extract (GSPE), are bioactive compounds present in plants and represent an interesting therapeutical approach for MASLD.

METHODS AND RESULTS

This study questioned whether the timing of GSPE administration impacts liver diurnal metabolism and steatosis in a rat obesity model. Results from hepatic lipid profiling and diurnal metabolic gene expression and metabolomics reveal that rats fed with a cafeteria (CAF) diet show impaired glucose homeostasis and enhanced lipogenesis in the liver, contributing to liver steatosis. Chronic consumption of GSPE in the inactive or active phase is associated with beneficial effects as the restoration of rhythms of transcripts and metabolites is observed. However, only when given in the active phase, GSPE treatment decreases hepatic triglyceride levels. Using an in vitro hepatocyte model, the study identifies that catechin, one of the main phenolic compounds found in the GSPE extract, is a potential mediator in ameliorating the effects of CAF-induced liver steatosis.

CONCLUSION

Taken altogether, the findings show that the beneficial effects of GSPE on MASLD development depend on the treatment time.

Associations of temporal patterns of objectively measured moderate-to-vigorous physical activity with mortality in the general population and people with abnormal glucose metabolism or hypertension

To investigate the association between temporal patterns of objectively measured moderate-to-vigorous physical activity (MVPA) and all-cause and cause-specific mortality in the general population and people with abnormal glucose metabolism (AGM) or hypertension. This prospective cohort study collected accelerometer data from the National Health and Nutrition Examination Survey from 2003 to 2006 with linkage to the National Death Index records through 31 December 2019 in the United States. Baseline 7-day accelerometry data were analysed and participants were categorized into 5 groups: morning/midday (05:00-13:59), afternoon (14:00-16:59), evening (17:00-19:59), night (20:00-00:59), and mixed MVPA timing groups. Cox regression analysis was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) between temporal patterns and mortality. A total of 5976 adults (mean [SE] age, 46.4 [0.5] years; 52.1% women) were included and 1371 participants died during a median follow-up of 14.6 years. Compared with the mixed group, the night group had 22% to 77% higher risks of all-cause and cardiovascular mortality in the overall sample and AGM and hypertension subsamples. In people with hypertension, the morning/midday group showed a 31% higher risk of cardiovascular mortality. For those with AGM, the evening group had 90% to 185% higher risks of all-cause and cardiovascular mortality.

Circadian rhythms in muscle health and diseases

All major life forms from bacteria to humans have internal clocks that regulate essential biological processes in a roughly 24-h cycle. In mammals, the central clock in the suprachiasmatic nucleus (SCN) is historically considered the top of a hierarchical organisation that dominates subordinate clocks in peripheral tissues and dictates the circadian behaviours of an organism. Recent studies, however, underscore the importance of the local circadian oscillators, such as the skeletal muscle clock, in regulating local metabolism and physiology. Studies in animal models show that the muscle peripheral clock per se is required for the expression of genes involved in glucose, lipid, and amino acid metabolism. Disruption of the muscle clock leads to glucose intolerance, insulin resistance, and alterations in muscle size and force. This highlights the vital role of the muscle clock in controlling muscle physiology and metabolism. In humans, a perturbation in the muscle circadian rhythms is seen in metabolic disorders such as type 2 diabetes, and muscle diseases such as dystrophies. Disruption of muscle metabolism is also seen when the internal rhythms are misaligned with the external rhythms (circadian misalignments) as in shift work. Understanding the mechanisms by which the muscle clock regulates circadian functions may help the development of new strategies, such as chronotherapy, to potentially prevent or treat muscle pathologies and maintain muscle health.

Morning physical activity may be more beneficial for blood lipids than afternoon physical activity in older adults: a cross-sectional study

BACKGROUND

The effect of differences in daily physical activity patterns on blood lipids has not been determined. This study examines the effects of the differences in free-living daily physical activity patterns (amount and intensity) on blood lipid levels in older adults.

METHODS

This cross-sectional study included 51 older participants (71.8 ± 0.6 years, men = 8, women = 43). A triaxial accelerometer was used to assess physical activity patterns. The time from awakening to bedtime for each participant was used for group classification based on the amount (number of steps) and intensity (moderate-to-vigorous physical activity, MVPA) of physical activity. The morning step group (M Step) was defined as those who took more steps in the morning, and the afternoon step group (A Step) was defined as those who took more steps in the afternoon. The same method was used for MVPA (morning MVPA: M MVPA; afternoon MVPA: A MVPA). Blood samples were collected at the start of the study to determine blood lipid levels.

RESULTS

Number of steps taken showed a trend toward lower low-density lipoprotein cholesterol (LDL-C) levels in the M Step group compared with the A Step group. The LDL/high-density lipoprotein (HDL) ratio was significantly lower in the M Step group than the A Step group (p < 0.05). The M MVPA group also had higher HDL-C levels and significantly lower LDL/HDL ratios than the A MVPA group (p < 0.05).

CONCLUSIONS

These results suggest that compared with afternoon physical activity, daily morning physical activity (amount and intensity) is more effective in improving blood lipid levels.

Intracellular metabolome elucidates the time-of-day-dependent response to hydrogen peroxide in salmonid gill epithelial cells

The internal timekeeping system regulates the daily cycle of physiological and behavioural changes in living organisms. This rhythmic phenomenon also influences cellular responses to reactive oxygen species, such as hydrogen peroxide (H2O2). However, the temporal interaction between H2O2 and fish mucosal cells is not well understood. This study examined the temporal variations of immunological and physiological responses to H2O2 in salmonid gill cells using the RTgill-W1 cell line. The results showed that gene expression levels varied during a 24-h cycle but did not exhibit rhythmicity. The presence of a 12-h light-dark cycle (12L:12D) signal increased gene expression levels compared to a 24-h dark cycle (0L:24D). To investigate whether the time of day affects the defences in gills, cells were exposed to H2O2 at two different times (Zeitgebertime 2, ZT2, or ZT14). Although significant expression changes were observed in genes related to stress and NF-κB signalling, only a limited time-dependent pattern of response to H2O2 was observed. The intracellular metabolome of gill cells was primarily composed of organic acid and derivatives, organoheterocyclic compounds, benzoids, organic oxygen and nitrogen compounds. Exposure to H2O2 at ZT2 led to significant changes in the metabolome compared to the control group, while no such changes were observed at ZT14. Within the control groups, the concentrations of 11 metabolites significantly varied between ZT2 and ZT14, with higher levels at ZT14. These metabolites were involved in arginine biosynthesis, amino acid metabolism, and nitrogen metabolism. In contrast, the level of 26 metabolites significantly varied between ZT2 and ZT14 in H2O2-exposed groups, with lower levels at ZT14. Comparing control and H2O2-exposed groups at ZT2, 38 metabolites were affected, primarily organic acid and derivatives and organic oxygen compounds. Functional annotation revealed that these altered metabolites were involved in 15 different pathways, with valine, leucine, and isoleucine biosynthesis being the most affected. This study reveals the presence of a time-dependent response to H2O2 in salmonid gill cells, which is reflected in the intracellular metabolome. The findings provide new insights into the temporal regulation of mucosal defences in fish.

Resilience to Chronic Stress Is Characterized by Circadian Brain-Liver Coordination

Background

Chronic stress has a profound impact on circadian regulation of physiology. In turn, disruption of circadian rhythms increases the risk of developing both psychiatric and metabolic disorders. To explore the role of chronic stress in modulating the links between neural and metabolic rhythms, we characterized the circadian transcriptional regulation across different brain regions and the liver as well as serum metabolomics in mice exposed to chronic social defeat stress, a validated model for studying depressive-like behaviors.

Methods

Male C57BL/6J mice underwent chronic social defeat stress, and subsequent social interaction screening identified distinct behavioral phenotypes associated with stress resilience and susceptibility. Stressed mice and their control littermates were sacrificed every 4 hours over the circadian cycle for comprehensive analyses of the circadian transcriptome in the hypothalamus, hippocampus, prefrontal cortex, and liver together with assessments of the circadian circulatory metabolome.

Results

Our data demonstrate that stress adaptation was characterized by reprogramming of the brain as well as the hepatic circadian transcriptome. Stress resiliency was associated with an increase in cyclic transcription in the hypothalamus, hippocampus, and liver. Furthermore, cross-tissue analyses revealed that resilient mice had enhanced transcriptional coordination of circadian pathways between the brain and liver. Conversely, susceptibility to social stress resulted in a loss of cross-tissue coordination. Circadian serum metabolomic profiles corroborated the transcriptome data, highlighting that stress-resilient mice gained circadian rhythmicity of circulating metabolites, including bile acids and sphingomyelins.

Conclusions

This study reveals that resilience to stress is characterized by enhanced metabolic rhythms and circadian brain-liver transcriptional coordination.

Effect of Endurance Exercise Training on Gut Microbiota and ER Stress

Regular exercise as part of one's lifestyle is well-recognized for its beneficial effect on several diseases such as cardiovascular disease and obesity; however, many questions remain unanswered regarding the effects of exercise on the gut environment. This study aimed to investigate the impact of long-term endurance exercise on modulating inflammation and endoplasmic reticulum (ER) stress. Fifteen-week-old male Sprague-Dawley (SD) rats were subjected to six months of endurance treadmill training, while age-matched controls remained sedentary. Results showed that IL-6 mRNA levels in colon tissues were significantly higher in the exercise group compared to the sedentary group. Exercise activated a significant ER stress-induced survival pathway by increasing BiP and phosphorylation of eIF2α (p-eIF2α) expressions in the liver and colon, while decreasing CHOP in the liver. Gene expressions of MUC2, Occludin, and Claudin-2 were increased in the colon of the exercise group, indicating enhanced intestinal integrity. Furthermore, the data showed a positive correlation between microbiota α-diversity and BiP (r = 0.464~0.677, p < 0.05). Populations of Desulfovibrio C21 c20 were significantly greater in the exercise group than the sedentary group. Additionally, predicted functions of the gut microbial community in terms of enzymes and pathways supported the enhancement of fatty-acid-related processes by exercise. These findings suggest that prolonged endurance exercise can affect the colon environment, which is likely related to changes in inflammation, ER stress, mucin layers and tight junctions, associated with modifications in the gut microbiome.

Exerkines: Benign adaptation for exercise and benefits for non-alcoholic fatty liver disease

Exercise has multiple beneficial effects on human metabolic health and is regarded as a "polypill" for various diseases. At present, the lack of physical activity usually causes an epidemic of chronic metabolic syndromes, including obesity, cardiovascular diseases, and non-alcoholic fatty liver disease (NAFLD). Remarkably, NAFLD is emerging as a serious public health issue and is associated with the development of cirrhosis and hepatocellular carcinoma. Unfortunately, specific drug therapies for NAFLD and its more severe form, non-alcoholic steatohepatitis (NASH), are currently unavailable. Lifestyle modification is the foundation of treatment recommendations for NAFLD and NASH, especially for exercise. There are under-appreciated organs that crosstalk to the liver during exercise such as muscle-liver crosstalk. Previous studies have reported that certain exerkines, such as FGF21, GDF15, irisin, and adiponectin, are beneficial for liver metabolism and have the potential to be targeted for NAFLD treatment. In addition, some of exerkines can be modified for the new proteins and get enhanced functions, like IL-6/IC7Fc. Another importance of exercise is the physiological adaptation that combats metabolic diseases. Thus, this review aims to summarize the known exerkines and utilize a multi-omics mining tool to identify more exerkines for the future research. Overall, understanding the mechanisms by which exercise-induced exerkines exert their beneficial effects on metabolic health holds promise for the development of novel therapeutic strategies for NAFLD and related diseases.

Diurnal timing of physical activity and risk of colorectal cancer in the UK Biobank

BACKGROUND

Physical activity reduces colorectal cancer risk, yet the diurnal timing of physical activity in colorectal cancer etiology remains unclear.

METHODS

This study used 24-h accelerometry time series from UK Biobank participants aged 42 to 79 years to derive circadian physical activity patterns using functional principal component analysis. Multivariable Cox proportional hazard models were used to examine associations with colorectal cancer risk.

RESULTS

Among 86,252 participants (56% women), 529 colorectal cancer cases occurred during a median 5.3-year follow-up. We identified four physical activity patterns that explained almost 100% of the data variability during the day. A pattern of continuous day-long activity was inversely associated with colorectal cancer risk (hazard ratio (HR) = 0.94, 95% confidence interval (CI) = 0.89-0.99). A second pattern of late-day activity was suggestively inversely related to risk (HR = 0.93, 95% CI = 0.85-1.02). A third pattern of early- plus late-day activity was associated with decreased risk (HR = 0.89, 95% CI = 0.80-0.99). A fourth pattern of mid-day plus night-time activity showed no relation (HR = 1.02, 95% CI = 0.88-1.19). Our results were consistent across various sensitivity analyses, including the restriction to never smokers, the exclusion of the first 2 years of follow-up, and the adjustment for shift work.

CONCLUSIONS

A pattern of early- plus late-day activity is related to reduced colorectal cancer risk, beyond the benefits of overall activity. Further research is needed to confirm the role of activity timing in colorectal cancer prevention.

Unlocking the secrets of exercise: A pathway to enhanced insulin sensitivity and skeletal muscle health in type 2 diabetes

•Exercise impacts skeletal muscle and systemic metabolism, yet understanding the complex molecular mechanisms behind these effects remains a key research challenge. •Mapping the molecular effects of exercise with advanced “omics” can advance our understanding of muscle function and metabolism. •Exercise holds promise for managing and preventing type 2 diabetes, emphasizing the need for more research on individualized training and its molecular effects.

A 2-hydroxybutyrate-mediated feedback loop regulates muscular fatigue

Several metabolites have been shown to have independent and at times unexpected biological effects outside of their metabolic pathways. These include succinate, lactate, fumarate, and 2-hydroxyglutarate. 2-Hydroxybutyrate (2HB) is a byproduct of endogenous cysteine synthesis, produced during periods of cellular stress. 2HB rises acutely after exercise; it also rises during infection and is also chronically increased in a number of metabolic disorders. We show here that 2HB inhibits branched-chain aminotransferase enzymes, which in turn triggers a SIRT4-dependent shift in the compartmental abundance of protein ADP-ribosylation. The 2HB-induced decrease in nuclear protein ADP-ribosylation leads to a C/EBPβ-mediated transcriptional response in the branched-chain amino acid degradation pathway. This response to 2HB exposure leads to an improved oxidative capacity in vitro. We found that repeated injection with 2HB can replicate the improvement to oxidative capacity that occurs following exercise training. Together, we show that 2-HB regulates fundamental aspects of skeletal muscle metabolism.

Exercise entrainment of musculoskeletal connective tissue clocks

The musculoskeletal system, crucial for movement and support, relies on the delicate balance of connective tissue homeostasis. Maintaining this equilibrium is essential for tissue health and function. There has been increasing evidence in the past decade that shows the circadian clock as a master regulator of extracellular matrix (ECM) homeostasis in several connective tissue clocks. Very recently, exercise has emerged as a significant entrainment factor for cartilage and intervertebral disk circadian rhythms. Understanding the implications of exercise on connective tissue peripheral clocks holds promise for enhancing tissue health and disease prevention. Exercise-induced factors such as heat, glucocorticoid release, mechanical loading, and inter-tissue cross talk may play pivotal roles in entraining the circadian rhythm of connective tissues. This mini review underscores the importance of elucidating the mechanisms through which exercise influences circadian rhythms in connective tissues to optimize ECM homeostasis. Leveraging exercise as a modulator of circadian rhythms in connective tissues may offer novel therapeutic approaches to physical training for preventing musculoskeletal disorders and enhancing recovery.

Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training

OBJECTIVE

In this investigation, we addressed the contribution of the core circadian clock factor, BMAL1, in skeletal muscle to both acute transcriptional responses to exercise and transcriptional remodeling in response to exercise training. Additionally, we adopted a systems biology approach to investigate how loss of skeletal muscle BMAL1 altered peripheral tissue homeostasis as well as exercise training adaptations in iWAT, liver, heart, and lung of male mice.

METHODS

Combining inducible skeletal muscle specific BMAL1 knockout mice, physiological testing and standardized exercise protocols, we performed a multi-omic analysis (transcriptomics, chromatin accessibility and metabolomics) to explore loss of muscle BMAL1 on muscle and peripheral tissue responses to exercise.

RESULTS

Muscle-specific BMAL1 knockout mice demonstrated a blunted transcriptional response to acute exercise, characterized by the lack of upregulation of well-established exercise responsive transcription factors including Nr4a3 and Ppargc1a. Six weeks of exercise training in muscle-specific BMAL1 knockout mice induced significantly greater and divergent transcriptomic and metabolomic changes in muscle. Surprisingly, liver, lung, inguinal white adipose and heart showed divergent exercise training transcriptomes with less than 5% of 'exercise-training' responsive genes shared for each tissue between genotypes.

CONCLUSIONS

Our investigation has uncovered the critical role that BMAL1 plays in skeletal muscle as a key regulator of gene expression programs for both acute exercise and training adaptations. In addition, our work has uncovered the significant impact that altered exercise response in muscle and its likely impact on the system plays in the peripheral tissue adaptations to exercise training. Our work also demonstrates that if the muscle adaptations diverge to a more maladaptive state this is linked to increased gene expression signatures of inflammation across many tissues. Understanding the molecular targets and pathways contributing to health vs. maladaptive exercise adaptations will be critical for the next stage of therapeutic design for exercise mimetics.

An exercise physiologist's guide to metabolomics

The field of exercise physiology has undergone significant technological advancements since the pioneering works of exercise physiologists in the early to mid-20th century. Historically, the ability to detect metabolites in biofluids from exercising participants was limited to single-metabolite analyses. However, the rise of metabolomics, a discipline focused on the comprehensive analysis of metabolites within a biological system, has facilitated a more intricate understanding of metabolic pathways and networks in exercise. This review explores some of the pivotal technological and bioinformatic advancements that have propelled metabolomics to the forefront of exercise physiology research. Metabolomics offers a unique 'fingerprint' of cellular activity, offering a broader spectrum than traditional single-metabolite assays. Techniques, including mass spectrometry and nuclear magnetic resonance spectroscopy, have significantly improved the speed and sensitivity of metabolite analysis. Nonetheless, challenges persist, including study design and data interpretation issues. This review aims to serve as a guide for exercise physiologists to facilitate better research design, data analysis and interpretation within metabolomics. The potential of metabolomics in bridging the gap between genotype and phenotype is emphasised, underscoring the critical importance of careful study design and the selection of appropriate metabolomics techniques. Furthermore, the paper highlights the need to deeply understand the broader scientific context to discern meaningful metabolic changes. The emerging field of fluxomics, which seeks to quantify metabolic reaction rates, is also introduced as a promising avenue for future research.

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.

Time of exercise differentially impacts bone growth in mice

Although physical training has been shown to improve bone mass, the time of day to exercise for optimal bone growth remains uncertain. Here we show that engaging in physical activity during the early active phase, as opposed to the subsequent active or rest phase, results in a more substantial increase in bone length of male and female mice. Transcriptomic and metabolomic methodologies identify that exercise during the early active phase significantly upregulates genes associated with bone development and metabolism. Notably, oxidative phosphorylation-related genes show a rhythmic expression in the chondrification centre, with a peak at the early active phase, when more rhythmic genes in bone metabolism are expressed and bone growth is synergistically promoted by affecting oxidative phosphorylation, which is confirmed by subsequent pharmacological investigations. Finally, we construct a signalling network to predict the impact of exercise on bone growth. Collectively, our research sheds light on the intricacies of human exercise physiology, offering valuable implications for interventions.

Non-rhythmic modulators of the circadian system: A new class of circadian modulators

The temporal organization of biological processes is critical for an organism's fitness and survival. An internal circadian clock network coordinates the alignment between the external and internal milieus via an array of systemic factors carrying temporal information such as core body temperature, autonomic activity, hormonal secretion, and behavioral functions. Collectively, these so called zeitgebers are characterized by strong temporal variations (i.e., high amplitudes). At the same time, target tissues show time windows of highest and lowest sensitivity to specific zeitgebers and, in this way, tissues can further modulate the effect of zeitgeber input in a process known as circadian gating. Such interplay between systemic signals and local circadian gating, however, suggests an additional level of temporal control-the resetting of target tissue rhythms in response to altered levels of tonic (i.e., non-rhythmic) signals. The recently identified tuning of liver transcriptome rhythms by thyroid hormones (THs) is one example of such regulation. THs show low-amplitude rhythms in the serum levels that are easily disrupted by altered thyroid states. At the same time, circadian rhythms in TH target tissues, such as liver, are markedly affected by alterations in TH state. Temporal regulation of TH target genes in other tissues suggests similar effects across the body. This chapter describes the rationale, experimental evidence, and potential consequences of this new level of circadian regulators.

The impact of aerobic exercise timing on BMAL1 protein expression and antioxidant responses in skeletal muscle of mice

It is well known that the adaptations of muscular antioxidant system to aerobic exercise depend on the frequency, intensity, duration, type of the exercise. Nonetheless, the timing of aerobic exercise, related to circadian rhythms or biological clock, may also affect the antioxidant defense system, but its impact remains uncertain. Bain and muscle ARNT-like 1 (BMAL1) is the core orchestrator of molecular clock, which can maintain cellular redox homeostasis by directly controlling the transcriptional activity of nuclear factor erythroid 2-related factor 2 (NRF2). So, our research objective was to evaluate the impacts of aerobic exercise training at various time points of the day on BMAL1 and NRF2-mediated antioxidant system in skeletal muscle. C57BL/6J mice were assigned to the control group, the group exercising at Zeitgeber Time 12 (ZT12), and the group exercising at ZT24. Control mice were not intervened, while ZT12 and ZT24 mice were trained for four weeks at the early and late time point of their active phase, respectively. We observed that the skeletal muscle of ZT12 mice exhibited higher total antioxidant capacity and lower reactive oxygen species compared to ZT24 mice. Furthermore, ZT12 mice improved the colocalization of BMAL1 with nucleus, the protein expression of BMAL1, NRF2, NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, glutamate-cysteine ligase modifier subunit and glutathione reductase in comparison to those of ZT24 mice. In conclusion, the 4-week aerobic training performed at ZT12 is more effective for enhancing NRF2-mediated antioxidant responses of skeletal muscle, which may be attributed to the specific activation of BMAL1.

Temporal dynamics of the multi-omic response to endurance exercise training

Regular exercise promotes whole-body health and prevents disease, but the underlying molecular mechanisms are incompletely understood1-3. Here, the Molecular Transducers of Physical Activity Consortium4 profiled the temporal transcriptome, proteome, metabolome, lipidome, phosphoproteome, acetylproteome, ubiquitylproteome, epigenome and immunome in whole blood, plasma and 18 solid tissues in male and female Rattus norvegicus over eight weeks of endurance exercise training. The resulting data compendium encompasses 9,466 assays across 19 tissues, 25 molecular platforms and 4 training time points. Thousands of shared and tissue-specific molecular alterations were identified, with sex differences found in multiple tissues. Temporal multi-omic and multi-tissue analyses revealed expansive biological insights into the adaptive responses to endurance training, including widespread regulation of immune, metabolic, stress response and mitochondrial pathways. Many changes were relevant to human health, including non-alcoholic fatty liver disease, inflammatory bowel disease, cardiovascular health and tissue injury and recovery. The data and analyses presented in this study will serve as valuable resources for understanding and exploring the multi-tissue molecular effects of endurance training and are provided in a public repository ( https://motrpac-data.org/ ).

Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training

Objectives

In this investigation, we addressed the contribution of the core circadian clock factor, BMAL1, in skeletal muscle to both acute transcriptional responses to exercise and transcriptional remodelling in response to exercise training. Additionally, we adopted a systems biology approach to investigate how loss of skeletal muscle BMAL1 altered peripheral tissue homeostasis as well as exercise training adaptations in iWAT, liver, heart, and lung of male mice.

Methods

Combining inducible skeletal muscle specific BMAL1 knockout mice, physiological testing and standardized exercise protocols, we performed a multi-omic analysis (transcriptomics, chromatin accessibility and metabolomics) to explore loss of muscle BMAL1 on muscle and peripheral tissue responses to exercise.

Results

Muscle-specific BMAL1 knockout mice demonstrated a blunted transcriptional response to acute exercise, characterized by the lack of upregulation of well-established exercise responsive transcription factors including Nr4a3 and Ppargc1a. Six weeks of exercise training in muscle-specific BMAL1 knockout mice induced significantly greater and divergent transcriptomic and metabolomic changes in muscle. Surprisingly, liver, lung, inguinal white adipose and heart showed divergent exercise training transcriptomes with less than 5% of 'exercise-training' responsive genes shared for each tissue between genotypes.

Conclusion

Our investigation has uncovered the critical role that BMAL1 plays in skeletal muscle as a key regulator of gene expression programs for both acute exercise and training adaptations. In addition, our work has uncovered the significant impact that altered exercise response in muscle plays in the peripheral tissue adaptation to exercise training. We also note that the transcriptome adaptations to steady state training suggest that without BMAL1, skeletal muscle does not achieve the expected homeostatic program. Our work also demonstrates that if the muscle adaptations diverge to a more maladaptive state this is linked to increased inflammation across many tissues. Understanding the molecular targets and pathways contributing to health vs. maladaptive exercise adaptations will be critical for the next stage of therapeutic design for exercise mimetics.

Ergothioneine boosts mitochondrial respiration and exercise performance via direct activation of MPST

Ergothioneine (EGT) is a diet-derived, atypical amino acid that accumulates to high levels in human tissues. Reduced EGT levels have been linked to age-related disorders, including neurodegenerative and cardiovascular diseases, while EGT supplementation is protective in a broad range of disease and aging models in mice. Despite these promising data, the direct and physiologically relevant molecular target of EGT has remained elusive. Here we use a systematic approach to identify how mitochondria remodel their metabolome in response to exercise training. From this data, we find that EGT accumulates in muscle mitochondria upon exercise training. Proteome-wide thermal stability studies identify 3-mercaptopyruvate sulfurtransferase (MPST) as a direct molecular target of EGT; EGT binds to and activates MPST, thereby boosting mitochondrial respiration and exercise training performance in mice. Together, these data identify the first physiologically relevant EGT target and establish the EGT-MPST axis as a molecular mechanism for regulating mitochondrial function and exercise performance.

Circadian regulation of cancer stem cells and the tumor microenvironment during metastasis

The circadian clock regulates daily rhythms of numerous physiological activities through tightly coordinated modulation of gene expression and biochemical functions. Circadian disruption is associated with enhanced tumor formation and metastasis via dysregulation of key biological processes and modulation of cancer stem cells (CSCs) and their specialized microenvironment. Here, we review how the circadian clock influences CSCs and their local tumor niches in the context of different stages of tumor metastasis. Identifying circadian therapeutic targets could facilitate the development of new treatments that leverage circadian modulation to ablate tumor-resident CSCs, inhibit tumor metastasis and enhance response to current therapies.

Identification and validation of serum metabolite biomarkers for endometrial cancer diagnosis

Endometrial cancer (EC) stands as the most prevalent gynecological tumor in women worldwide. Notably, differentiation diagnosis of abnormity detected by ultrasound findings (e.g., thickened endometrium or mass in the uterine cavity) is essential and remains challenging in clinical practice. Herein, we identified a metabolic biomarker panel for differentiation diagnosis of EC using machine learning of high-performance serum metabolic fingerprints (SMFs) and validated the biological function. We first recorded the high-performance SMFs of 191 EC and 204 Non-EC subjects via particle-enhanced laser desorption/ionization mass spectrometry (PELDI-MS). Then, we achieved an area-under-the-curve (AUC) of 0.957-0.968 for EC diagnosis through machine learning of high-performance SMFs, outperforming the clinical biomarker of cancer antigen 125 (CA-125, AUC of 0.610-0.684, p < 0.05). Finally, we identified a metabolic biomarker panel of glutamine, glucose, and cholesterol linoleate with an AUC of 0.901-0.902 and validated the biological function in vitro. Therefore, our work would facilitate the development of novel diagnostic biomarkers for EC in clinics.

Influence of High-Intensity Interval Training on Neuroplasticity Markers in Post-Stroke Patients: Systematic Review

Background: Exercise has shown beneficial effects on neuronal neuroplasticity; therefore, we want to analyze the influence of high-intensity interval training (HIIT) on neuroplasticity markers in post-stroke patients. Methods: A systematic review of RCTs including studies with stroke participants was conducted using the following databases (PubMed, LILACS, ProQuest, PEDro, Web of Science). Searches lasted till (20/11/2023). Studies that used a HIIT protocol as the main treatment or as a coadjutant treatment whose outcomes were neural plasticity markers were used and compared with other exercise protocols, controls or other kinds of treatment. Studies that included other neurological illnesses, comorbidities that interfere with stroke or patients unable to complete a HIIT protocol were excluded. HIIT protocol, methods to assess intensity, neuroplasticity markers (plasmatic and neurophysiological) and other types of assessments such as cognitive scales were extracted to make a narrative synthesis. Jadad and PEDro scales were used to assess bias. Results: Eight articles were included, one included lacunar stroke (less than 3 weeks) and the rest had chronic stroke. The results found here indicate that HIIT facilitates neuronal recovery in response to an ischemic injury. This type of training increases the plasma concentrations of lactate, BDNF and VEGF, which are neurotrophic and growth factors involved in neuroplasticity. HIIT also positively regulates other neurophysiological measurements that are directly associated with a better outcome in motor learning tasks. Conclusions: We conclude that HIIT improves post-stroke recovery by increasing neuroplasticity markers. However, a limited number of studies have been found indicating that future studies are needed that assess this effect and include the analysis of the number of intervals and their duration in order to maximize this effect.

Exercise ameliorates fine particulate matter-induced metabolic damage through the SIRT1/AMPKα/PGC1-α/NRF1 signaling pathway

Air pollution, particularly fine particulate matter (PM2.5), poses a major threat to human health. Exercise has long been recognized as a beneficial way to maintain physical health. However, there is limited research on whether exercise can mitigate the damage caused by PM2.5 exposure. In this study, the mice were exercised on the IITC treadmill for 1 h per day, then exposed to concentrated PM2.5 for 8 h. After 2, 4 and 6-month exercise and PM2.5 exposure, the glucose tolerance and insulin tolerance were determined. Meanwhile, the corresponding indicators in epididymal white adipose tissue (eWAT), brown adipose tissue (BAT) and skeletal muscle were detected. The results indicated that PM2.5 exposure significantly increased insulin resistance (IR), while exercise effectively attenuated this response. The observations of muscle, BAT and eWAT by transmission electron microscopy (TEM) showed that PM2.5 significantly reduced the number of mitochondria in all of the three tissues mentioned above, and decreased the mitochondrial area in skeletal muscle and BAT. Exercise reversed the changes in mitochondrial area in all of the three tissues, but had no effect on the reduction of mitochondrial number in skeletal muscle. At 2 months, the expressions of Mfn2, Mfn1, OPA1, Drp1 and Fis1 in eWAT of the PM mice showed no significant changes when compared with the corresponding FA mice. However, at 4 months and 6 months, the expression levels of these genes in PM mice were higher than those in the FA mice in skeletal muscle. Exercise intervention significantly reduced the upregulation of these genes induced by PM exposure. The study indicated that PM2.5 may impact mitochondrial biogenesis and dynamics by inhibiting the SIRT1/AMPKα/PGC1-α/NRF1 pathway, which further lead to IR, glucose and lipid disorders. However, exercise might alleviate the damages caused by PM2.5 exposure.

Impacts of glutamate, an exercise-responsive metabolite on insulin signaling

AIMS

Disruption of the insulin signaling pathway leads to insulin resistance (IR). IR is characterized by impaired glucose and lipid metabolism. Elevated levels of circulating glutamate are correlated with metabolic indicators and may potentially predict the onset of metabolic diseases. Glutamate receptor antagonists have significantly enhanced insulin sensitivity, and improved glucose and lipid metabolism. Exercise is a well-known strategy to combat IR. The aims of our narrative review are to summarize preclinical and clinical findings to show the correlations between circulating glutamate levels, IR and metabolic diseases, discuss the causal role of excessive glutamate in IR and metabolic disturbance, and present an overview of the exercise-induced alteration in circulating glutamate levels.

MATERIALS AND METHODS

A literature search was conducted to identify studies on glutamate, insulin signaling, and exercise in the PubMed database. The search covered articles published from December 1955 to January 2024, using the search terms of "glutamate", "glutamic acid", "insulin signaling", "insulin resistance", "insulin sensitivity", "exercise", and "physical activity".

KEY FINDINGS

Elevated levels of circulating glutamate are correlated with IR. Excessive glutamate can potentially hinder the insulin signaling pathway through various mechanisms, including the activation of ectopic lipid accumulation, inflammation, and endoplasmic reticulum stress. Glutamate can also modify mitochondrial function through Ca2+ and induce purine degradation mediated by AMP deaminase 2. Exercise has the potential to decrease circulating levels of glutamate, which can be attributed to accelerated glutamate catabolism and enhanced glutamate uptake.

SIGNIFICANCE

Glutamate may act as a mediator in the exercise-induced improvement of insulin sensitivity.