Activation of AMPK and its Impact on Exercise Capacity

Sex-Specific Antioxidant and Anti-Inflammatory Protective Effects of AMPK in Cardiovascular Diseases

Cardiovascular diseases such as coronary heart disease, heart failure, or stroke are the most common cause of death worldwide and are regularly based on risk factors like diabetes mellitus, hypertension, or obesity. At the same time, both diseases and risk factors are significantly influenced by sex hormones. In order to better understand this influence and also specifically improve the therapy of female patients, medical research has recently focused increasingly on gender-specific differences. The goal is to develop personalized, gender-specific therapy concepts for these diseases to further enhance health outcomes. The enzyme adenosine monophosphate-activated protein kinase (AMPK) is a central regulator of energy metabolism, protecting the cardiovascular system from energy depletion, thereby promoting vascular health and preventing cellular damage. AMPK confers cardioprotective effects by preventing endothelial and vascular dysfunction, and by controlling or regulating oxidative stress and inflammatory processes. For AMPK, sex-specific effects were reported, influencing metabolic and cardiovascular responses. Exercise and metabolic stress generally cause higher AMPK activity in males. At the same time, females exhibit protective mechanisms against insulin resistance or oxidative stress, particularly in conditions like obesity. Additionally, males subject to AMPK deficiency seem to experience greater cardiac and mitochondrial dysfunction. In contrast, females show improvement in cardiovascular function after pharmacological AMPK activation. These differences, influenced by hormones, body composition, and gene expression, highlight the potential to develop personalized, sex-specific AMPK-targeted therapeutic strategies for cardiovascular diseases in the future. Here, we discuss the most actual scientific background, focusing on the protective, gender-specific effects of AMPK, and highlight potential clinical applications.

Two-Dimensional Liquid Chromatography Purified GC/C/IRMS Doping Control Method: Analysis of Endogenous and Exogenous Sources in Urine Samples from Asian Subjects Administered a Low Dose of AICAR

AICAR (5-amino-4-imidazolecarboxyamide ribonucleoside), as a metabolic modulator, is classified in the S4 category by the World Anti-Doping Agency (WADA). Carbon Isotope Ratio Mass Spectrometry (CIR) is the mainstream method for distinguishing the endogenous and exogenous sources of AICAR in urine due to the significant individual difference in the concentration. The purpose of this study is to establish a gas chromatography combustion Isotope Ratio Mass Spectrometry (GC/C/IRMS) method for AICAR based on efficient two-dimensional liquid chromatography (2D-HPLC) separation.

METHOD

In this study, an automated 2D-HPLC separation technique was used to separate and purify AICAR and endogenous reference substances in urine samples. Then, AICAR was derivatized with 3-TMS as the main derivative product, while the endogenous reference compounds remained in their original form. Subsequently, the developed GC/C/IRMS method was utilized for the detection of the target and reference substances. Followed, we evaluated the applicability of this method using urine samples from two Asian males administered a low dose of AICAR (3 grams).

RESULTS

The advantages of this study include: 1) reduced sample pretreatment time: the established 2D-HPLC separation method can separate the target and endogenous reference substances in one step; 2) low interference: the isotope chromatograms have low background interference, and the separation of endogenous reference substances is purer; 3) more accurate result calculations: this method only requires derivatization and result correction for AICAR, with the endogenous reference substances measured in their original form, reducing biases from corrections of multiple substances. The detection method performed well, with a concentriton limit of 2500 ng/mL, meeting the needs of routine detection concentrations. The CIR results from volunteer samples indicated that samples collected within 16 hours post-administration exceeded the threshold set in the literature.

CONCLUSION

This study successfully established a 2D-HPLC-GC/IRMS method that integrates CIR as the most stable indicator for distinguishing the internal and external sources of AICAR. After administering a low dose of AICAR to the Asian population, exogenous drug characteristics were manifested within 16 hours. This observation, when compared to the 40-hour detection window cited in the literature, suggests that the length of the detection window is positively correlated with the dosage of the test drug.

Far-infrared therapy promotes exercise capacity and glucose metabolism in mice by modulating microbiota homeostasis and activating AMPK

The benefits of physical exercise on human health make it desirable to identify new approaches that would mimic or potentiate the effects of exercise to treat metabolic diseases. However, whether far-infrared (FIR) hyperthermia therapy could be used as exercise mimetic to realize wide-ranging metabolic regulation, and its underling mechanisms remain unclear. Here, a specific far-infrared (FIR) rays generated from graphene-based hyperthermia devices might promote exercise capacity and metabolisms. The material characterization showed that the graphene synthesized by chemical vapour deposition (CVD) was different from carbon fiber, with single-layer structure and high electrothermal transform efficiency. The emission spectra generated by graphene-FIR device would maximize matching those adsorbed by tissues. Graphene-FIR enhanced both core and epidermal temperatures, leading to increased blood flow in the femoral muscle and the abdominal region. The combination of microbiomic and metabolomic analysis revealed that graphene-FIR modulates the metabolism of the gut-muscle axis. This modulation was characterized by an increased abundance of short-chain fatty acids (SCFA)-producing bacteria and AMP, while lactic acid levels decreased. Furthermore, the principal routes involved in glucose metabolism, such as glycolysis and gluconeogenesis, were found to be altered. Graphene-FIR managed to stimulate AMPK activity by activating GPR43, thus enhancing muscle glucose uptake. Furthermore, a microbiota disorder model also demonstrated that the graphene-FIR effectively restore the exercise endurance with enhanced p-AMPK and GLUT4. Our results provided convincing evidence that graphene-based FIR therapy promoted exercise capacity and glucose metabolism via AMPK in gut-muscle axis. These novel findings regarding the therapeutic effects of graphene-FIR suggested its potential utility as a mimetic agent in clinical management of metabolic disorders.

Comprehensive analysis of prohibited substances and methods in sports: Unveiling trends, pharmacokinetics, and WADA evolution

This review systematically compiles sports-related drugs, substances, and methodologies based on the most frequently detected findings from prohibited lists published annually by the World Anti-Doping Agency (WADA) between 2003 and 2021. Aligned with structure of the 2023 prohibited list, it covers all proscribed items and details the pharmacokinetics and pharmacodynamics of five representatives from each section. Notably, it explores significant metabolites and metabolic pathways associated with these substances. Adverse analytical findings are summarized in tables for clarity, and the prevalence is visually represented through charts. The review includes a concise historical overview of doping and WADA's role, examining modifications in the prohibited list for an understanding of evolving anti-doping measures.

AMPK, a key molecule regulating aging-related myocardial ischemia-reperfusion injury

Aging leads to the threat of more diseases to the biological anatomical structure and the decline of disease resistance, increasing the incidence and mortality of myocardial ischemia-reperfusion injury (MI/RI). Moreover, MI/RI promotes damage to an aging heart. Notably, 5'-adenosine monophosphate-activated protein kinase (AMPK) regulates cellular energy metabolism, stress response, and protein metabolism, participates in aging-related signaling pathways, and plays an essential role in ischemia-reperfusion (I/R) injury diseases. This study aims to introduce the aging theory, summarize the interaction between aging and MI/RI, and describe the crosstalk of AMPK in aging and MI/RI. We show how AMPK can offer protective effects against age-related stressors, lifestyle factors such as alcohol consumption and smoking, and hypertension. We also review some of the clinical prospects for the development of interventions that harness the effect of AMPK to treat MI/RI and other age-related cardiovascular diseases.

3'sialyllactose and 6'sialyllactose enhance performance in endurance-type exercise through metabolic adaptation

Human milk oligosaccharides (HMOs) belong to a group of multifunctional glycans that are abundantly present in human breast milk. While health effects of neutral oligosaccharides have been investigated extensively, a lot remains unknown regarding health effects of acidic oligosaccharides, such as the two sialyllactoses (SLs), 3'sialyllactose (3'SL), and 6'sialyllactose (6'SL). We utilized Caenorhabditis elegans (C. elegans) to investigate the effects of SLs on exercise performance. Using swimming as an endurance-type exercise, we found that SLs decrease exhaustion, signifying an increase in endurance that is strongest for 6'SL. Through an unbiased metabolomics approach, we identified changes in energy metabolism that correlated with endurance performance. Further investigation suggested that these metabolic changes were related to adaptations of muscle mitochondria that facilitated a shift from beta oxidation to glycogenolysis during exercise. We found that the effect of SLs on endurance performance required AMPK- (aak-1/aak-2) and adenosine receptor (ador-1) signaling. We propose a model where SLs alter the metabolic status in the gut, causing a signal from the intestine to the nervous system toward muscle cells, where metabolic adaptation increases exercise performance. Together, our results underline the potential of SLs in exercise-associated health and contribute to our understanding of the molecular processes involved in nutritionally-induced health benefits.

Exercise improves homeostasis of the intestinal epithelium by activation of apelin receptor-AMP-activated protein kinase signalling

Intestinal remodelling is dynamically regulated by energy metabolism. Exercise is beneficial for gut health, but the specific mechanisms remain poorly understood. Intestine-specific apelin receptor (APJ) knockdown (KD) and wild-type male mice were randomly divided into two subgroups, with/without exercise, to obtain four groups: WT, WT with exercise, APJ KD and APJ KD with exercise. Animals in the exercise groups were subjected to daily treadmill exercise for 3 weeks. Duodenum was collected at 48 h after the last bout of exercise. AMP-activated protein kinase (AMPK) α1 KD and wild-type mice were also utilized for investigating the mediatory role of AMPK on exercise-induced duodenal epithelial development. AMPK and peroxisome proliferator-activated receptor γ coactivator-1 α were upregulated by exercise via APJ activation in the intestinal duodenum. Correspondingly, exercise induced permissive histone modifications in the PR domain containing 16 (PRDM16) promoter to activate its expression, which was dependent on APJ activation. In agreement, exercise elevated the expression of mitochondrial oxidative markers. The expression of intestinal epithelial markers was downregulated due to AMPK deficiency, and AMPK signalling facilitated epithelial renewal. These data demonstrate that exercise-induced activation of the APJ-AMPK axis facilitates the homeostasis of the intestinal duodenal epithelium. KEY POINTS: Apelin receptor (APJ) signalling is required for improved epithelial homeostasis of the small intestine in response to exercise. Exercise intervention activates PRDM16 through inducing histone modifications, enhanced mitochondrial biogenesis and fatty acid metabolism in duodenum. The morphological development of duodenal villus and crypt is enhanced by the muscle-derived exerkine apelin through the APJ-AMP-activated protein kinase axis.

Maternal exercise intergenerationally drives muscle-based thermogenesis via activation of apelin-AMPK signaling

BACKGROUND

Sarcolipin and uncoupling protein 3 (UCP3) mediate muscle-based non-shivering thermogenesis (NST) to improve metabolic homeostasis. The impacts of maternal obesity (MO) and maternal exercise (ME) on NST in offspring muscle remain unexamined.

METHODS

Female mice were fed with a control diet or high fat diet to induce obesity. Then, obese mice were further separated into two groups: obesity only (OB) and OB plus daily exercise (OB/Ex). Fetal muscle was collected at embryonic day 18.5 and offspring mice at 3-month-old. Apelin administration during pregnancy and apelin receptor (APJ) knockout mouse were further used for investigating the mediatory role of APJ on muscle-based thermogenesis. To explore the direct effects of exercise on AMP-activated protein kinase (AMPK) downstream targets, AMPK knockout mouse was used.

FINDINGS

MO inhibited while ME activated AMPK and peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α) in fetal muscle. AMPK activation increased sarcolipin expression, which inhibited the uptake of calcium ions into sarcoplasmic reticulum, thereby activating CaMKK2. Consistently, the expression of UCP3 and sarcolipin was suppressed due to MO but activated in ME fetal muscle. Importantly, changes of UCP3 and sarcolipin maintained in offspring muscle, showing the transgenerational effects. Furthermore, apelin administration during pregnancy mimicked the effects of ME on AMPK and CaMKK2 activation, and UCP3 and sarcolipin expression, underscoring the mediatory roles of apelin-AMPK signaling in improving fetal muscle development.

INTERPRETATION

ME, via activation of apelin signaling-AMPK axis, enhances NST gene expression in fetal and offspring muscle impaired due to MO, which intergenerationally protects offspring from diet-induced obesity and metabolic disorders.

FUNDING

This work was supported by National Institutes of Health Grant R01-HD067449.

Marine Oil from C. finmarchicus Enhances Glucose Homeostasis and Liver Insulin Resistance in Obese Prediabetic Individuals

The intermediate state between normal glucose tolerance and overt type 2 diabetes mellitus is associated with micro- and macrovascular diseases, requiring safe and cost-effective treatment measures interventions. A novel source of LC n-3 FAs is Calanus finmarchicus Oil, which showed promising effects on glucose homeostasis in preclinical studies due to anti-obesity effects and/or anti-inflammatory properties. In total, 43 obese patients (BMI: 31.7 ± 5.2 kg/m²) were allocated in the following two groups: (1) Calanus oil group (2 g CO/day) and (2) placebo group (2 g paraffin oil/day). Markers of glucose metabolism, body composition and energy intake were measured at the beginning (t0), after 12 weeks (t₁₂) and 16 weeks (t₁₆). Overall, parameters reflecting abnormal glucose homeostasis and insulin resistance in the liver, including fasting insulin (−2.9 mU/L ± 4.10, p < 0.05), HOMA-IR (−0.9 ± 1.28, p < 0.05) and hepatic insulin resistance index (−1.06 ± 1.72 × 10⁶, p < 0.05) significantly enhanced after a 12-week CO-intervention, while no differences were observed in HbA1c, AUC_0–2h Glucose, AUC_0–2h Insulin, 2 h plasma glucose and muscle insulin sensitivity index. Our results indicate that Calanus oil causes beneficial effects on glucose metabolism and insulin resistance in obese patients, with clinical relevance to be verified in further studies. In addition, the possible active compounds and their mechanisms of action should be elucidated.

A Quick Guide to Small-Molecule Inhibitors of Eukaryotic Protein Synthesis

Eukaryotic ribosome and cap-dependent translation are attractive targets in the antitumor, antiviral, anti-inflammatory, and antiparasitic therapies. Currently, a broad array of small-molecule drugs is known that specifically inhibit protein synthesis in eukaryotic cells. Many of them are well-studied ribosome-targeting antibiotics that block translocation, the peptidyl transferase center or the polypeptide exit tunnel, modulate the binding of translation machinery components to the ribosome, and induce miscoding, premature termination or stop codon readthrough. Such inhibitors are widely used as anticancer, anthelmintic and antifungal agents in medicine, as well as fungicides in agriculture. Chemicals that affect the accuracy of stop codon recognition are promising drugs for the nonsense suppression therapy of hereditary diseases and restoration of tumor suppressor function in cancer cells. Other compounds inhibit aminoacyl-tRNA synthetases, translation factors, and components of translation-associated signaling pathways, including mTOR kinase. Some of them have antidepressant, immunosuppressive and geroprotective properties. Translation inhibitors are also used in research for gene expression analysis by ribosome profiling, as well as in cell culture techniques. In this article, we review well-studied and less known inhibitors of eukaryotic protein synthesis (with the exception of mitochondrial and plastid translation) classified by their targets and briefly describe the action mechanisms of these compounds. We also present a continuously updated database (http://eupsic.belozersky.msu.ru/) that currently contains information on 370 inhibitors of eukaryotic protein synthesis.

A Whole Food Plant-Based Diet Is Effective for Weight Loss: The Evidence

What does the best available balance of scientific evidence show is the optimum way to lose weight? Calorie density, water content, protein source, and other components significantly influence the effectiveness of different dietary regimes for weight loss. By "walling off your calories," preferentially deriving your macronutrients from structurally intact plant foods, some calories remain trapped within indigestible cell walls, which then blunts the glycemic impact, activates the ileal brake, and delivers prebiotics to the gut microbiome. This may help explain why the current evidence indicates that a whole food, plant-based diet achieves greater weight loss compared with other dietary interventions that do not restrict calories or mandate exercise. So, the most effective diet for weight loss appears to be the only diet shown to reverse heart disease in the majority of patients. Plant-based diets have also been found to help treat, arrest, and reverse other leading chronic diseases such as type 2 diabetes and hypertension, whereas low-carbohydrate diets have been found to impair artery function and worsen heart disease, the leading killer of men and women in the United States. A diet centered on whole plant foods appears to be a safe, simple, sustainable solution to the obesity epidemic.

Pterostilbene Enhances Endurance Capacity via Promoting Skeletal Muscle Adaptations to Exercise Training in Rats

It has been demonstrated that skeletal muscle adaptions, including muscle fibers transition, angiogenesis, and mitochondrial biogenesis are involved in the regular exercise-induced improvement of endurance capacity and metabolic status. Herein, we investigated the effects of pterostilbene (PST) supplementation on skeletal muscle adaptations to exercise training in rats. Six-week-old male Sprague Dawley rats were randomly divided into a sedentary control group (Sed), an exercise training group (Ex), and exercise training combined with 50 mg/kg PST (Ex + PST) treatment group. After 4 weeks of intervention, an exhaustive running test was performed, and muscle fiber type transformation, angiogenesis, and mitochondrial content in the soleus muscle were measured. Additionally, the effects of PST on muscle fiber transformation, paracrine regulation of angiogenesis, and mitochondrial function were tested in vitro using C2C12 myotubes. In vivo study showed that exercise training resulted in significant increases in time-to-exhaustion, the proportion of slow-twitch fibers, muscular angiogenesis, and mitochondrial biogenesis in rats, and these effects induced by exercise training could be augmented by PST supplementation. Moreover, the in vitro study showed that PST treatment remarkably promoted slow-twitch fibers formation, angiogenic factor expression, and mitochondrial function in C2C12 myotubes. Collectively, our results suggest that PST promotes skeletal muscle adaptations to exercise training thereby enhancing the endurance capacity.

Swimming Exercise Protects against Insulin Resistance via Regulating Oxidative Stress through Nox4 and AKT Signaling in High-Fat Diet-Fed Mice

Nonpharmaceutical therapies such as exercise training and diet intervention are widely used for the treatment of insulin resistance (IR). Although the skeletal muscle is the major peripheral tissue of glucose metabolism under insulin stimulation, the mechanism underlying muscle IR is poorly understood. Using a high-fat diet-induced IR mouse model, we here show that NADPH oxidase 4 (Nox4) upregulation mediates the production of reactive oxygen species (ROS) that causes metabolic syndrome featuring IR. The Nox4 expression level was markedly elevated in IR mice, and Nox4 overexpression was sufficient to trigger IR. Conversely, downregulation of Nox4 expression through exercise training prevented diet-induced IR by reducing the production of ROS and enhancing the AKT signaling pathway. Thus, this study indicates that exercise might improve IR through a reduction of Nox4-induced ROS in the skeletal muscle and enhancement of AKT signal transduction.

A novel AMPK activator improves hepatic lipid metabolism and leukocyte trafficking in experimental hepatic steatosis

A novel AMP-activated protein kinase (AMPK) activator, IMM-H007 (H007), has been reported to reduce serum lipid levels and inhibit lipid accumulation in the liver in hyperlipidemic animal models. However, how H007 ameliorates hepatic steatosis and inflammation remains unknown. In the present study, H007, at 200 mg/kg, reduced hepatic lipid levels and the levels of collagenous fiber in the liver in high-fat diet (HFD)-fed hamsters compared to those in the HFD group. Meanwhile, compared to the controls, H007 significantly inhibited sterol-regulatory element binding protein (SREBP)-1c and acetyl CoA carboxylase (ACC) expression by upregulating the AMPK activity, suppressing the saturated fatty acid accumulation and increasing polyunsaturated fatty acid synthesis in the liver. Compared to the controls, H007 treatment inhibited the expression of monocyte chemotactic protein (MCP-1) in fatty acid-treated HepG2 cells; suppressed leukocyte adherence and rolling on the liver microvasculature; and suppressed hepatic macrophage infiltration. H007 also suppressed the expression of nuclear factor-κB (NF-κB) p65 in fatty acid- and lipopolysaccharide-treated HepG2 cells compared to that in the controls by activating AMPK. These data suggested that H007 had a beneficial effect by improving the lipid composition in the liver and inhibiting inflammatory cell trafficking in the development of nonalcoholic fatty liver disease.

Exercise prevents the adverse effects of maternal obesity on placental vascularization and fetal growth

KEY POINTS

Maternal exercise improves the metabolic health of maternal mice challenged with a high-fat diet. Exercise intervention of obese mothers prevents fetal overgrowth. Exercise intervention reverses impaired placental vascularization in obese mice. Maternal exercise activates placental AMP-activated protein kinase, which was inhibited as a result of maternal obesity.

ABSTRACT

More than one-third of pregnant women in the USA are obese and maternal obesity (MO) negatively affects fetal development, which predisposes offspring to metabolic diseases. The placenta mediates nutrient delivery to fetuses and its function is impaired as a result of MO. Exercise ameliorates metabolic dysfunction resulting from obesity, although its effect on placental function of obese mothers has not been explored. In the present study, C57BL/6J female mice were randomly assigned into two groups fed either a control or a high-fat diet (HFD) and then the mice on each diet were further divided into two subgroups with/without exercise. In HFD-induced obese mice, daily treadmill exercise during pregnancy reduced body weight gain, lowered serum glucose and lipid concentration, and improved insulin sensitivity of maternal mice. Importantly, maternal exercise prevented fetal overgrowth (macrosomia) induced by MO. To further examine the preventive effects of exercise on fetal overgrowth, placental vascularization and nutrient transporters were analysed. Vascular density and the expression of vasculogenic factors were reduced as a result of MO but were recovered by maternal exercise. On the other hand, the contents of nutrient transporters were not substantially altered by MO or exercise, suggesting that the protective effects of exercise in MO-induced fetal overgrowth were primarily a result of the alteration of placental vascularization and improved maternal metabolism. Furthermore, exercise enhanced downstream insulin signalling and activated AMP-activated protein kinase in HFD placenta. In sum, maternal exercise prevented fetal overgrowth induced by MO, which was associated with improved maternal metabolism and placental vascularization in obese mothers with exercise.

Review of WADA Prohibited Substances: Limited Evidence for Performance-Enhancing Effects

The World Anti-Doping Agency is responsible for maintaining a Prohibited List that describes the use of substances and methods that are prohibited for athletes. The list currently contains 23 substance classes, and an important reason for the existence of this list is to prevent unfair competition due to pharmacologically enhanced performance. The aim of this review was to give an overview of the available evidence for performance enhancement of these substance classes. We searched the scientific literature through PubMed for studies and reviews evaluating the effects of substance classes on performance. Findings from double-blind, randomized controlled trials were considered as evidence for (the absence of) effects if they were performed in trained subjects measuring relevant performance outcomes. Only 5 of 23 substance classes show evidence of having the ability to enhance actual sports performance, i.e. anabolic agents, β2-agonists, stimulants, glucocorticoids and β-blockers. One additional class, growth hormone, has similar evidence but only in untrained subjects. The observed effects all relate to strength or sprint performance (and accuracy for β-blockers); there are no studies showing positive effects on reliable markers of endurance performance. For 11 classes, no well-designed studies are available, and, for the remaining six classes, there is evidence of an absence of a positive effect. In conclusion, for the majority of substance classes, no convincing evidence for performance enhancement is available, while, for the remaining classes, the evidence is based on a total of only 266 subjects from 11 studies.

Strength training and aerobic exercise alter mitochondrial parameters in brown adipose tissue and equally reduce body adiposity in aged rats

With aging, there is a reduction in mitochondrial activity, and several changes occur in the body composition, including increased adiposity. The dysfunction of mitochondrial activity causes changes and adaptations in tissue catabolic characteristics. Among them, we can mention brown adipose tissue (BAT). BAT's main function is lipid oxidation for heat production, hence playing a role in adaptive thermogenesis induced by environmental factors such as exercise. It is known that exercise causes a series of metabolic changes, including loss body fat; however, there is still no consensus in the academic community about whether both strength and aerobic exercise equally reduces adiposity. Therefore, this study aimed to evaluate the effects of strength training and aerobic exercise regimes on adiposity, proteins regulating mitochondrial activity, and respiratory complexes in BAT of old rats. The rats were divided in two control groups: young control (YC; N = 5), and old control (OC; N = 5), and two exercise groups: strength training (OST; N = 5), and aerobic treadmill training (OAT; N = 5). Rats were subjected to an 8-week exercise regime, and their body composition parameters were evaluated (total body weight, adiposity index, and BAT weight). In addition, mitochondrial biogenesis proteins (PGC-1α, SIRT1, and pAMPK) and respiratory chain activity (complexes I, II/III, III, and IV) were evaluated. Results showed that OST and OAT exercise protocols significantly increased the mitochondrial regulatory molecules and respiratory chain activity, while body fat percentage and adiposity index significantly decreased. Taken together, both OST and OAT exercise increased BAT weight, activity of respiratory complexes, and regulatory proteins in BAT and equally reduced body adiposity.

Inula Japonica Thunb. Flower Ethanol Extract Improves Obesity and Exercise Endurance in Mice Fed A High-Fat Diet

Inula japonica Thunb. (Asteraceae) is a flowering plant that grows mainly in Korea, Japan, and China and its flower extract has diverse biological effects such as anti-inflammatory and antioxidative activities. However, the effects on obesity and enhancement of endurance capacity have not been explored yet. This study aims to reveal the effects of I. japonica flower ethanol extract (IJE) on obesity and endurance capacity in high-fat diet (HFD) fed C57BL/6J mice and the mechanism. IJE inhibited lipid accumulation in 3T3-L1 adipocytes in vitro. Also, IJE-fed mice showed reduced body weight gain, hepatic lipid, and body fat mass, and increased muscle weight. IJE reduced lipid accumulation in the liver and adipose tissue by decreasing lipogenic and adipogenic gene expression. Additionally, consumption of low-dose IJE significantly enhanced endurance capacity via increasing AMP-activated protein kinase activity and mRNA levels of Myh7 and Myh2. Luteolin and 1β-hydroxyalantolactone (1β-HA), compounds of IJE, are involved in anti-adipogenesis in the 3T3-L cells and only luteolin increased the protein levels of MHC during C2C12 myoblast differentiation. Collectively, our results suggest that consumption of IJE not only helps to prevent obesity but also enhances endurance capacity reduced by HFD.

The impact of endurance exercise on global and AMPK gene-specific DNA methylation

Alterations in gene expression as a consequence of physical exercise are frequently described. The mechanism of these regulations might depend on epigenetic changes in global or gene-specific DNA methylation levels. The AMP-activated protein kinase (AMPK) plays a key role in maintenance of energy homeostasis and is activated by increases in the AMP/ATP ratio as occurring in skeletal muscles after sporting activity. To analyze whether exercise has an impact on the methylation status of the AMPK promoter, we determined the AMPK methylation status in human blood samples from patients before and after sporting activity in the context of rehabilitation as well as in skeletal muscles of trained and untrained mice. Further, we examined long interspersed nuclear element 1 (LINE-1) as indicator of global DNA methylation changes. Our results revealed that light sporting activity in mice and humans does not alter global DNA methylation but has an effect on methylation of specific CpG sites in the AMPKα2 gene. These regulations were associated with a reduced AMPKα2 mRNA and protein expression in muscle tissue, pointing at a contribution of the methylation status to AMPK expression. Taken together, these results suggest that exercise influences AMPKα2 gene methylation in human blood and eminently in the skeletal muscle of mice and therefore might repress AMPKα2 gene expression.

Energy disruptors: rising stars in anticancer therapy?

The metabolic features of tumor cells diverge from those of normal cells. Otto Warburg was the first to observe that cancer cells dramatically increase their glucose consumption to generate ATP. He also claimed that cancer cells do not have functional mitochondria or oxidative phosphorylation (OXPHOS) but simply rely on glycolysis to provide ATP to the cell, even in the presence of oxygen (aerobic glycolysis). Several studies have revisited this observation and demonstrated that most cancer cells contain metabolically efficient mitochondria. Indeed, to sustain high proliferation rates, cancer cells require functional mitochondria to provide ATP and intermediate metabolites, such as citrate and cofactors, for anabolic reactions. This difference in metabolism between normal and tumors cells causes the latter to be more sensitive to agents that can disrupt energy homeostasis. In this review, we focus on energy disruptors, such as biguanides, 2-deoxyglucose and 5-aminoimidazole-4-carboxamide ribonucleotide, that interfere with the main metabolic pathways of the cells, OXPHOS, glycolysis and glutamine metabolism. We discuss the preclinical data and the mechanisms of action of these disruptors at the cellular and molecular levels. Finally, we consider whether these drugs can reasonably contribute to the antitumoral therapeutic arsenal in the future.