Exercise training-driven exosomal miRNA-323-5p activity suppresses adipogenic conversion of 3T3-L1 cells via the DUSP3/ERK pathway.

Adipose-derived stem cell (ASC)-released exosomes (ASCexos) have multiple biological activities. We examined the effect of ASCexos derived from the inguinal adipose tissue of exercise-trained rats (EX-ASCexos) on adipogenic conversion of 3T3-L1 cells and analyzed their microRNA (miRNA) expression profiles. Differentiation of 3T3-L1 cells into adipocytes was performed for 9 d with EX-ASCexos or ASCexos from sedentary control rats (SED-ASCexos), and the expression of proteins and miRNA involved in adipogenic differentiation were determined. EX-ASCexos but not SED-ASCexos attenuated 3T3-L1 adipocyte differentiation with increased phosph-Ser112PPARγ expression, the inactive form of PPARγ. These differentiated adipocytes were also accompanied by increased phosph-Thr202/Tyr204ERK and decreased dual-specificity phosphatase 3 (DUSP3) levels. The exosomal miRNAs miR-323-5p, miR-433-3p, and miR-874-3p were identified specifically in EX-ASCexos. Of these, miR-323-5p mimic replicated the EX-ASCexo-induced suppression of 3T3-L1 adipocyte differentiation and altered adipogenesis-related factor expression. In conclusion, exercise training-driven exosomal miR-323-5p suppressed 3T3-L1 adipogenesis by increasing phosph-Ser112PPARγ expression, while phosph-Thr202/Tyr204ERK accumulation inhibited DUSP3 expression.

High-intensity interval training enhances mRNA expression of IGF1Ea in rat Achilles tendon.

High-intensity interval training (HIIT) reportedly enhances the functional properties of the musculoskeletal system. However, the effects of HIIT on tendons remain unclear. Sixteen male rats were randomly assigned to the control (Con) or HIIT group (n = 8 in each group). Rats in the HIIT group executed the HIIT program consisting of 2.5 min treadmill running and 4.5 min rests between the bouts, 5 days per week for 9 weeks. Running speed, number of sets, and inclination were incrementally increased during the training period. Histological analysis revealed no apparent morphological changes in the extracellular matrix structure or nuclei of tenocytes between the groups. Real-time reverse transcription polymerase chain reaction analysis revealed that Igf1Ea mRNA expression was enhanced in the HIIT group. Furthermore, Igfbp5 mRNA expression tended to be higher in the HIIT group. The 9-week HIIT program enhanced tenogenic Igf1Ea mRNA expression.

Impact of high-intensity interval training on tendon related gene expression in rat Achilles tendon.

Immobilization or aging associated with limited physical activity can lead to the functional deterioration of tendons, which has become an important public health concern. Therefore, growing research is focused on the effect of exercise training on preserving tendon function. Exercise training subjects muscles and tendons to repeated mechanical stress, and in vitro studies have revealed that repetitive mechanical loading stimulates tendon cell responses to changes in the extracellular matrix and functional properties of the tendon. However, although several types of exercise training have been shown to be effective in preserving tendon function, no studies have investigated the impact of high-intensity interval training (HIIT), which involves composing short bouts of exercise with high-power output. Here, we determined whether the HIIT program enhanced tenogenic progressions by measuring the mRNA expression in rat Achilles tendons. Sixteen rats were randomly assigned into either a sedentary control group (Con, n = 8) or an HIIT group (n = 8). Rats in the HIIT group performed the program with treadmill running; the training volume was incremental (running speed, number of sets, and inclination), and training was conducted 5 days per week for 9 weeks. The rats in the HIIT group exhibited a marked decrease in the body weight and different types of fat weights, and a marked increase in different types of muscle weights. Real-time reverse transcription polymerase chain reaction analysis revealed that mRNA expressions of tendon-related genes Tnxb, Opn, and Tgfb1 were upregulated in the HIIT group compared to that in the Con group. Cross-links in mRNA expressions of collagen-related Dcn and Fmod in the HIIT group tended to be higher than in those Con group. These results suggest that HIIT induces initiation of tenogenic progression and stimulation of cross-link formation between collagen fibrils in rat Achilles tendons.

Depression of Bone Density at the Weight-Bearing Joints in Wistar Hannover Rats by a Simulated Mechanical Stress Associated With Partial Gravity Environment.

The partial gravity environment in space can negatively affect bone health. This survey aimed to study the reaction of different parts of the lower limb bones of rats to partial gravity and the effects of different degrees of gravity on these bony parts. We used 15 8-week-old male Wistar Hannover rats were used at the beginning of the experiment. The degree of mechanical stress was modified, but the ankle joint was maintained at ∼30°, ∼120°, or ∼160° with or without plaster fixation during 10-day hindlimb suspension. Computed tomography was performed to measure the bone parameters [bone mineral density (BMD), trabecular BMD, cortical BMD, and cortical thickness] of each studied group of the whole, proximal, middle, and distal femur and distal tibia. BMD, trabecular BMD, and cortical thickness of the distal femur and proximal tibia of the simulated mechanical stress associated with partial gravity groups were significantly lower than those of the control group; the effect of different degrees of gravity on the same area of hindlimb bone had no significant difference. The simulated mechanical stress associated with partial gravity had the most significant effect on the bone close to the knee joint, with the largest weight-bearing response.

Metabolomic Profiles in Adipocytes Differentiated from Adipose-Derived Stem Cells Following Exercise Training or High-Fat Diet.

Controlling the differentiation potential of adipose-derived stem cells (ADSCs) is attracting attention as a new strategy for the prevention and treatment of obesity. Here, we aimed to observe the effect of exercise training (TR) and high-fat diet (HFD) on the metabolic profiles of ADSCs-derived adipocytes. The rats were divided into four groups: normal diet (ND)-fed control (ND-SED), ND-fed TR (ND-TR), HFD-fed control (HFD-SED), and HFD-fed TR (HFD-TR). After 9 weeks of intervention, ADSCs of epididymal and inguinal adipose tissues were differentiated into adipocytes. In the metabolome analysis of adipocytes after isoproterenol stimulation, 116 metabolites were detected. The principal component analysis demonstrated that ADSCs-derived adipocytes segregated into four clusters in each fat pad. Amino acid accumulation was greater in epididymal ADSCs-derived adipocytes of ND-TR and HFD-TR, but lower in inguinal ADSCs-derived adipocytes of ND-TR, than in the respective controls. HFD accumulated several metabolites including amino acids in inguinal ADSCs-derived adipocytes and more other metabolites in epididymal ones. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that TR mainly affected the pathways related to amino acid metabolism, except in inguinal ADSCs-derived adipocytes of HFD-TR rats. These findings provide a new way to understand the mechanisms underlying possible changes in the differentiation of ADSCs due to TR or HFD.

Homeobox A5 and C10 genes modulate adaptation of brown adipose tissue during exercise training in juvenile rats.

NEW FINDINGS: What is the central question of this study? Exercise can stimulate brown adipose tissue (BAT) with subsequent increase in uncoupling protein 1 expression and mitochondrial biogenesis. In that case, do BAT-specific Hox genes modify BAT functioning and cause uncoupling protein expression changes due to exercise? What is the main finding and its importance? Exercise enhanced brown adipocyte markers, with significant upregulation of HoxA5 and downregulation of HoxC10 mRNA expression in rat BAT. HoxA5 and HoxC10 are thus likely to play distinct roles in exercise-induced changes in BAT markers during the early postnatal period. These findings provide new insight into the mechanisms underlying exercise-induced changes in BAT function. ABSTRACT: Brown adipose tissue (BAT) recruitment is involved in increased energy expenditure associated with cold exposure and exercise training. We explored whether exercise training induced changes in expression levels of brown adipocyte-selective factors and Homeobox (Hox) genes during the post-weaning growth period of male Wistar rats. Relative to total body weight, BAT weights alone were lower in exercise-trained (EX) rats compared to sedentary control (SED) rats. mRNA expression of HoxA5 was higher and that of HoxC10 was lower in EX rats than in SED rats, accompanied by both higher citrate synthase activity and protein expression levels for uncoupling protein 1 (UCP1), peroxisome proliferator-activated receptor (PPAR) α, and PPARγ-coactivator (PGC)-1α. HoxA5 knockdown with siRNA reduced the expression of PR-domain containing 16 (Prdm16), cell death-inducing DNA fragmentation factor-α-like effector A (Cidea) gene, type 2 deiodinase mRNA, and PRDM16 protein. Comparatively, HoxC10 knockdown with siRNA enhanced mRNA expression of Prdm16, Pparα and Pgc1α and protein expression of UCP1, PPARα and PGC1α in brown adipocytes. The stimulation of brown adipocytes with isoproterenol, a ß-adrenoceptor agonist, caused a phenomenon similar to the effect of exercise training on the genes tested: upregulation of HoxA5 mRNA, downregulation of HoxC10 mRNA, and increased protein expression for UCP1 and PGC1α. Collectively, HoxA5 and HoxC10 may have unique functions that contribute to modulating the expression of BAT-selective markers in BAT of juvenile rats during exercise training. The study findings regarding activation and recruitment of BAT during exercise training have implications for anti-obesity management.

Exercise Training-Enhanced Lipolytic Potency to Catecholamine Depends on the Time of the Day.

Exercise training is well known to enhance adipocyte lipolysis in response to hormone challenge. However, the existence of a relationship between the timing of exercise training and its effect on adipocyte lipolysis is unknown. To clarify this issue, Wistar rats were run on a treadmill for 9 weeks in either the early part (E-EX) or late part of the active phase (L-EX). L-EX rats exhibited greater isoproterenol-stimulated lipolysis expressed as fold induction over basal lipolysis, with greater protein expression levels of hormone-sensitive lipase (HSL) phosphorylated at Ser 660 compared to E-EX rats. Furthermore, we discovered that Brain and muscle Arnt-like (BMAL)1 protein can associate directly with several protein kinase A (PKA) regulatory units (RIα, RIß, and RIIß) of protein kinase, its anchoring protein (AKAP)150, and HSL, and that the association of BMAL1 with the regulatory subunits of PKA, AKAP150, and HSL was greater in L-EX than in E-EX rats. In contrast, comparison between E-EX and their counterpart sedentary control rats showed a greater co-immunoprecipitation only between BMAL1 and ATGL. Thus, both E-EX and L-EX showed an enhanced lipolytic response to isoproterenol, but the mechanisms underlying exercise training-enhanced lipolytic response to isoproterenol were different in each group.

Effects of physical activity and melatonin on brain-derived neurotrophic factor and cytokine expression in the cerebellum of high-fat diet-fed rats.

AIMS: Obesity suppresses brain-derived neurotrophic factor (BDNF) expression and increases the expression of pro-inflammatory cytokines. Herein, we assessed whether exercise training (ET), melatonin administration (MT), or their combination can affect the expressions of BDNF and cytokines in the cerebellum of high-fat diet (HFD)-fed rats. METHODS: Wistar rats (4 weeks old) were divided into five groups: normal diet (ND)-fed control (ND-SED), HFD-fed control (HFD-SED), HFD-fed ET (HFD-ET), HFD-fed MT (HFD-MT), and HFD-fed MT plus ET (HFD-ETMT) group. The rats were fed ND or HFD for 17 weeks. Rats were subjected to ET (running on a treadmill) and/or MT (melatonin 5 mg/kg body weight, i.p.) for 9 weeks, 8 weeks after beginning the diet intervention. Changes in BDNF and cytokine expression levels were determined using immunoblotting and cytokine arrays, respectively, 36 hours following the last bout of ET. RESULTS: Neither HFD-ET nor HFD-MT rats exhibited enhanced BDNF expression in the cerebellum, but HFD-ETMT rats had higher level of BDNF expression compared with the others. The expression of TrkB, a BDNF receptor, was higher in HFD-ETMT rats than in HFD-ET and HFD-MT rats. HFD enhanced the expression of interleukin (IL)-1, IL-2, and interferon-γ but reduced the expression of IL-4, IL-6, and IL13. ET and ET plus MT counteracted these HFD-induced changes in cytokine expressions. CONCLUSION: Exercise in combination with melatonin confers the potential benefits of increasing BDNF and improving HFD-induced dysregulations of cytokines in the cerebellum.

Exercise ameliorates high-fat diet-induced impairment of differentiation of adipose-derived stem cells into neuron-like cells in rats.

Adipose-derived stem cells (ADSCs) can differentiate into neurons under particular conditions. It remains largely unknown whether this differentiation potential is affected by physical conditions such as obesity, which modulates the functions of adipose tissue. In this study, we determined the impact of either a 9-week high-fat diet (60% fat; HFD) or 9-week exercise training on the differentiation potential of ADSCs into neuron-like cells in male Wistar rats. Rats were randomly assigned to a normal diet-fed (ND-SED) group, HFD-fed (HFD-SED) group, or exercise-trained HFD-fed group (HFD-EX). After a 9-week intervention, ADSCs from all groups differentiated into neuron-like cells. Expression of neuronal marker proteins (nestin, ßIII-tubulin, and microtubule-associated protein 2 [MAP2]) and the average length of cell neurites were lower in cells from HFD-SED rats than in other groups. Instead, protein expression of COX IV and Cyt-c, the Bax/Bcl-2 and LC3-II/I ratio, and the malondialdehyde level in culture medium were higher in cells from HFD-SED rats. No significant difference between ND-SED and HFD-EX rats was observed, except for the average length of cell neurites in MAP2. Thus, HFD impaired the differentiation potential of ADSCs into neuron-like cells, which was accompanied by increases in apoptotic activity and oxidative stress. Importantly, exercise training ameliorated the HFD-induced impairment of neurogenesis in ADSCs. The adipose tissue microenvironment could influence the differentiation potential of ADSCs, a source of autologous stem cell therapy.

Effect of a 9-week exercise training regimen on expression of developmental genes related to growth-dependent fat expansion in juvenile rats.

This study examined the association between changes in mRNA expression of development-related genes including those of the homeobox (Hox) family and growth-dependent increases in inguinal, mesenteric, and epididymal white adipose tissue (WAT) at 4, 6, 10, and 14 weeks of age in rats. We also examined the effects of a 9-week exercise training regimen starting at 5 weeks of age on the mRNA levels of the genes of interest. HoxC8, HoxC9, Gpc4, Bmpr1a, Pparγ, Pgc1α, Adrb3, Hsl, leptin, and adiponectin in each type of WAT - except HoxA5, Gpc4, and Pgc1α in epididymal - showed a positive association between WAT weights and WAT mRNA levels; however, the slope of the regression lines exhibited fat depot-specific differences. HoxA5 showed no significant association, and Gpc4 and Pgc1α showed a negative association in epididymal WAT. After exercise training, the mean HoxA5, HoxC8, HoxC9, HoxC10, Gpc4, Pparγ, and Pgc1α mRNA levels in inguinal WAT were outliers on the regression line between mean mRNA level and WAT weight in control rats - that is, mean HoxA5 and Pgc1α mRNA level was higher, whereas HoxC8, HoxC9, HoxC10, Gpc4, and Ppar levels were lower in exercise-trained rats than in same-age controls. Pparγγ and adiponectin levels were upregulated in epididymal WAT, while HoxA5 was downregulated, but HoxC9, Gpc4, Pparγ, and adiponectin levels were upregulated in mesenteric WAT. These results suggest that some of the developmental genes tested may have fat depot-specific roles in the growth-dependent expansion of WAT, and that Hox genes that are activated in response to exercise training also vary among different WAT types.

Differential response of adipose tissue gene and protein expressions to 4- and 8-week administration of ß-guanidinopropionic acid in mice.

ß-Guanidinopropionic acid (ß-GPA) feeding inhibits growth-associated gain of body mass. It remains unknown, however, whether and how ß-GPA feeding affects growth-associated increase in white adipose tissue (WAT) mass. We examined the effects of 4- and 8-week ß-GPA feeding on serum myostatin levels and expression of genes and proteins related to adipogenesis, lipolysis, and liposynthesis in epididymal WAT (eWAT) and brown adipose tissue (BAT) in 3-week-old, juvenile male mice. Body, eWAT, and muscle weights were significantly lower in ß-GPA-fed mice than in controls after feeding. Four- but not 8-week-ß-GPA feeding increased the serum myostatin level. Incubation of C2C12 myotubes with ß-GPA (1 mM) significantly promoted myostatin mRNA expression. The protein expression of peroxisome proliferator-activated receptor gamma coactivator 1 α (PGC-1α) and peroxisome proliferator-activated receptor α (PPARα) was up-regulated in GPAF eWAT at week 4, but down-regulated at week 8. There was no significant difference in the protein expression of adipocyte triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) between groups in eWAT. In BAT, no significant difference was found in the protein expression of PGC-1α, PPARα, ATGL, and HSL between ß-GPA-fed and control mice, whereas that of FAS and ACC was significantly lower in ß-GPA-fed mice at week 8. Uncoupling protein 1 was expressed higher in ß-GPA-fed mice both at weeks 4 and 8 than that in controls. Thus, the mechanism by which ß-GPA feeding in early juvenile mice inhibits growth-associated increase in eWAT mass may differ between early and later periods of growth.

Exercise Training Attenuates the Dysregulated Expression of Adipokines and Oxidative Stress in White Adipose Tissue.

Obesity-induced inflammatory changes in white adipose tissue (WAT), which caused dysregulated expression of inflammation-related adipokines involving tumor necrosis factor-α and monocyte chemoattractant protein-1, contribute to the development of insulin resistance. Moreover, current literature reports state that WAT generates reactive oxygen species (ROS), and the enhanced production of ROS in obese WAT has been closely associated with the dysregulated expression of adipokines in WAT. Therefore, the reduction in excess WAT and oxidative stress that results from obesity is thought to be one of the important strategies in preventing and improving lifestyle-related diseases. Exercise training (TR) not only brings about a decrease in WAT mass but also attenuates obesity-induced dysregulated expression of the adipokines in WAT. Furthermore, some reports indicate that TR affects the generation of oxidative stress in WAT. This review outlines the impact of TR on the expression of inflammation-related adipokines and oxidative stress in WAT.

Endurance exercise training induces fat depot-specific differences in basal autophagic activity.

The purpose of this study was to uncover the effect of exercise training on the expression of autophagy marker proteins in epididymal white adipose tissue (eWAT), inguinal WAT (iWAT), and the stromal vascular fraction (SVF) collected from eWAT. Male Wistar rats aged 4-5 weeks were randomly divided into two groups, sedentary control (n = 7) and exercise-trained (n = 7). Rats in the exercise-trained group were exercised on a treadmill set at a 5° incline 5 days/week for 9 weeks. We determined that the expression levels of an autophagosome-associating form of microtubule-associated protein 1 light chain 3 (LC3)-II and of p62 were significantly higher in eWAT from exercise-trained than from control rats, while those of adipose-specific deletion of autophagy-related protein (ATG7) and lysosomal-associated membrane protein type 2A (LAMP2a) showed no difference between groups. However, in iWAT, the expression levels of LC3-II and ATG7 were significantly higher in exercise-trained than in control rats. The expression of p62 was highly correlated with that of peroxisome proliferator-activated receptor γ (PPARγ), a master regulator of adipogenesis and lipid metabolism, in both WAT types (eWAT, r = 0.856, P < 0.05; iWAT, r = 0.762, P < 0.05), whereas LC3-II and PPARγ levels were highly correlated in eWAT (r = 0.765, P < 0.05) but not in iWAT (r = -0.306, ns). In SVF, the expression levels of LC3II, ATG7, and LAMP2a were significantly higher in exercise-trained than in control rats. These results suggest that exercise training suppresses basal autophagy activity in eWAT, but that this activity is enhanced in iWAT and SVF collected from eWAT. Thus, the adaptation of basal autophagic activity following exercise training exhibits fat depot-specific differences.

Habitual exercise training acts as a physiological stimulator for constant activation of lipolytic enzymes in rat primary white adipocytes.

It is widely accepted that lipolysis in adipocytes are regulated through the enzymatic activation of both hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) via their phosphorylation events. Accumulated evidence shows that habitual exercise training (HE) enhances the lipolytic response in primary white adipocytes with changes in the subcellular localization of lipolytic molecules. However, no study has focused on the effect that HE exerts on the phosphorylation of both HSL and ATGL in primary white adipocytes. It has been shown that the translocation of HSL from the cytosol to lipid droplet surfaces requires its phosphorylation at Ser-563. In primary white adipocytes obtained from HE rats, the level of HSL and ATGL proteins was higher than that in primary white adipocytes obtained from sedentary control (SC) rats. In HE rats, the level of phosphorylated ATGL and HSL was also significantly elevated compared with that in SC rats. These differences were confirmed by Phos-tag SDS-PAGE, a technique used to measure the amount of total phosphorylated proteins. Our results suggest that HE can consistently increase the activity of both lipases, thereby enhancing the lipolysis in white fat cells. Thus, HE helps in the prevention and treatment of obesity-related diseases by enhancing the lipolytic capacity.

Melatonin promotes adipogenesis and mitochondrial biogenesis in 3T3-L1 preadipocytes.

Melatonin is synthesized in the pineal gland, but elicits a wide range of physiological responses in peripheral target tissues. Recent advances suggest that melatonin controls adiposity, resulting in changes in body weight. The aim of this study was to investigate the effect of melatonin on adipogenesis and mitochondrial biogenesis in 3T3-L1 mouse embryo fibroblasts. Melatonin significantly increased the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), a master regulator of adipogenesis, and promoted differentiation into adipocytes. Melatonin-treated cells also formed smaller lipid droplets and abundantly expressed several molecules associated with lipolysis, including adipose triglyceride lipase, perilipin, and comparative gene identification-58. Moreover, the hormone promoted biogenesis of mitochondria, as indicated by fluorescent staining, elevated the citrate synthase activity, and upregulated the expression of PPAR-γ coactivator 1 α, nuclear respiratory factor-1, and transcription factor A. The expression of uncoupling protein 1 was also observable both at mRNA and at protein level in melatonin-treated cells. Finally, adiponectin secretion and the expression of adiponectin receptors were enhanced. These results suggest that melatonin promotes adipogenesis, lipolysis, mitochondrial biogenesis, and adiponectin secretion. Thus, melatonin has potential as an anti-obesity agent that may reverse obesity-related disorders.

The Molecular Mechanism Underlying Continuous Exercise Training-Induced Adaptive Changes of Lipolysis in White Adipose Cells.

Physical exercise accelerates the mobilization of free fatty acids from white adipocytes to provide fuel for energy. This happens in several tissues and helps to regulate a whole-body state of metabolism. Under these conditions, the hydrolysis of triacylglycerol (TG) that is found in white adipocytes is known to be augmented via the activation of these lipolytic events, which is referred to as the "lipolytic cascade." Indeed, evidence has shown that the lipolytic responses in white adipocytes are upregulated by continuous exercise training (ET) through the adaptive changes in molecules that constitute the lipolytic cascade. During the past few decades, many lipolysis-related molecules have been identified. Of note, the discovery of a new lipase, known as adipose triglyceride lipase, has redefined the existing concepts of the hormone-sensitive lipase-dependent hydrolysis of TG in white adipocytes. This review outlines the alterations in the lipolytic molecules of white adipocytes that result from ET, which includes the molecular regulation of TG lipases through the lipolytic cascade.

Endurance training facilitates myoglobin desaturation during muscle contraction in rat skeletal muscle.

At onset of muscle contraction, myoglobin (Mb) immediately releases its bound O2 to the mitochondria. Accordingly, intracellular O2 tension (PmbO2) markedly declines in order to increase muscle O2 uptake (mVO2). However, whether the change in PmbO2 during muscle contraction modulates mVO2 and whether the O2 release rate from Mb increases in endurance-trained muscles remain unclear. The purpose of this study was, therefore, to determine the effect of endurance training on O2 saturation of Mb (SmbO2) and PmbO2 kinetics during muscle contraction. Male Wistar rats were subjected to a 4-week swimming training (Tr group; 6 days per week, 30 min × 4 sets per day) with a weight load of 2% body mass. After the training period, deoxygenated Mb kinetics during muscle contraction were measured using near-infrared spectroscopy under hemoglobin-free medium perfusion. In the Tr group, the VmO2peak significantly increased by 32%. Although the PmbO2 during muscle contraction did not affect the increased mVO2 in endurance-trained muscle, the O2 release rate from Mb increased because of the increased Mb concentration and faster decremental rate in SmbO2 at the maximal twitch tension. These results suggest that the Mb dynamics during muscle contraction are contributing factors to faster VO2 kinetics in endurance-trained muscle.

Effect of Circadian Rhythm on Clinical and Pathophysiological Conditions and Inflammation.

Circadian rhythms have long been known to regulate numerous physiological processes that vary across the diurnal cycle. The circadian clock system also controls various parameters of the immune system and its biological defense functions, allowing an organism to anticipate daily changes in activity and feeding and the associated risk of infection. Inflammation is an immune response triggered in living organisms in response to external stimuli. The risk of sepsis, an excessive inflammatory response, has been shown to have a diurnal variation. On the other hand, inflammatory responses are emerging to be induced by endogenous factors. Recent studies have suggested that chronic inflammation causes chronic diseases including rheumatoid arthritis, allergies, and aging-related diseases and that proteins encoded by clock genes affect the development of such chronic inflammatory diseases or increase the severity of their symptoms. Therefore, detailed understanding of circadian rhythm effects on inflammatory responses is expected to lead to new strategies for prevention or treatment of inflammatory diseases.

Direct and indirect suppression of interleukin-6 gene expression in murine macrophages by nuclear orphan receptor REV-ERBα.

It is now evident that many nuclear hormone receptors can modulate target gene expression. REV-ERBα, one of the nuclear hormone receptors with the capacity to alter clock function, is critically involved in lipid metabolism, adipogenesis, and the inflammatory response. Recent studies suggest that REV-ERBα plays a key role in the mediation between clockwork and inflammation. The purpose of the current study was to investigate the role of REV-ERBα in the regulation of interleukin-6 (il6) gene expression in murine macrophages. REV-ERBα agonists, or overexpression of rev-erb α in the murine macrophage cell line RAW264 cells, suppressed the induction of il6 mRNA following a lipopolysaccharide (LPS) endotoxin challenge. Also, rev-erb α overexpression decreased LPS-stimulated nuclear factor κB (NFκB) activation in RAW264 cells. We showed that REV-ERBα represses il6 expression not only indirectly through an NFκB binding motif but also directly through a REV-ERBα binding motif in the murine il6 promoter region. Furthermore, peritoneal macrophages from mice lacking rev-erb α increased il6 mRNA expression. These data suggest that REV-ERBα regulates the inflammatory response of macrophages through the suppression of il6 expression. REV-ERBα may therefore be identified as a potent anti-inflammatory receptor and be a therapeutic target receptor of inflammatory diseases.

ETAS, an enzyme-treated asparagus extract, attenuates amyloid beta-induced cellular disorder in PC12 cells.

One of the pathological characterizations of Alzheimer's disease (AD) is the deposition of amyloid beta peptide (Abeta) in cerebral cortical cells. The deposition of Abeta in neuronal cells leads to an increase in the production of free radicals that are typified by reactive oxygen species (ROS), thereby inducing cell death. A growing body of evidence now suggests that several plant-derived food ingredients are capable of scavenging ROS in mammalian cells. The purpose of the present study was to investigate whether enzyme-treated asparagus extract (ETAS), which is rich in antioxidants, is one of these ingredients. The pre-incubation of differentiated PC 12 cells with ETAS significantly recovered Abeta-induced reduction of cell viability, which was accompanied by reduced levels of ROS. These results suggest that ETAS may be one of the functional food ingredients with anti-oxidative capacity to help prevent AD.