Takuya Sakurai

In recent years, brown adipose tissue (BAT), which has a high heat-producing capacity, has been confirmed to exist even in adults, and it has become a focal point for the prevention and the improvement of obesity and lifestyle-related diseases. However, the influences of obesity and physical activity (PA) on the fluid factors secreted from BAT (brown adipokines) are not well understood. In this study, therefore, we focused on brown adipokines and investigated the effects of obesity and PA. The abnormal expressions of gene fluid factors such as galectin-3 (Lgals3) and Lgals3 binding protein (Lgals3bp), whose proteins are secreted from HB2 brown adipocytes, were observed in the interscapular BAT of obese mice fed a high-fat diet for 4 months. PA attenuated the abnormalities in the expressions of these genes. Furthermore, although the gene expressions of factors related to brown adipocyte differentiation such as peroxisome proliferator-activated receptor gamma coactivator 1-α were also down-regulated in the BAT of the obese mice, PA suppressed the down-regulation of these factors. On the other hand, lipogenesis was increased more in HB2 cells overexpressing Lgals3 compared with that in control cells, and the overexpression of Lgals3bp decreased the mitochondrial mass. These results indicate that PA attenuates the obesity-induced dysregulated expression of brown adipokines and suggests that Lgals3 and Lgals3bp are involved in brown adipocyte differentiation.

Background: The intra‐individual reference range is generally narrower than the commonly used reference range. Consequently, close monitoring of changes in the laboratory test results of individuals based on the inter‐individual reference range remains challenging. Methods: We examined the determination of individual reference ranges using four indicators of nutritional conditions: transferrin (TRF), albumin (ALB), retinol‐binding protein (RBP), and transthyretin (TTR). The subjects comprised 20 healthy individuals and blood samples were collected and tested five times at 2‐week intervals. We used the measurement results for the four indicators and examined individual reference ranges using four methods, including calculation methods based on the reference change value and Bayesian inference. Results: The resulting intra‐individual reference ranges were narrower than the currently used inter‐individual reference range for all measurements using four methods. Furthermore, the intra‐individual coefficient of variation [CV (intra)] was smaller than the inter‐individual coefficient of variation [CV (inter)] for TRF, RBP, and TTR for all 20 subjects. The means CV (intra) for the four indicators were also lower than the corresponding CV (inter). Conclusions: The intra‐individual reference range can be used to validate the standard deviation and coefficient of variation for currently used indicators. Moreover, Bayesian methods are speculated to be the most versatile.

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, RIβ, and RIIβ) 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.

Heat shock protein 70 (HSP70) exhibits protective effects against ultraviolet (UV)-induced premature skin aging. A standardized extract of Asparagus officinalis stem (EAS) is produced as a novel and unique functional food that induces HSP70 cellular expression. To elucidate the anti-photoaging potencies of EAS, we examined its effects on HSP70 expression levels in UV-B-irradiated normal human dermal fibroblasts (NHDFs). NHDFs were treated with 1 mg/mL of EAS or dextrin (vehicle control) prior to UV-B irradiation (20 mJ/cm2). After culturing NHDFs for different time periods, HSP70 mRNA and protein levels were analyzed using real-time polymerase chain reaction and western blotting, respectively. UV-B-irradiated NHDFs showed reduced HSP70 mRNA levels after 1–6 h of culture, which were recovered after 24 h of culture. Treatment with EAS alone for 24 h increased HSP70 mRNA levels in the NHDFs, but the increase was not reflected in its protein levels. On the other hand, pretreatment with EAS abolished the UV-B irradiation-induced reduction in HSP70 expression at both mRNA and protein levels. These results suggest that EAS is capable to preserve HSP70 quantity in UV-B-irradiated NHDFs. EAS exhibits anti-photoaging potencies by preventing the reduction in HSP70 expression in UV-irradiated dermal fibroblasts.

We recently reported that ETAS 50, a standardized extract from the Asparagus officinalis stem, exerted anti‐inflammatory effects on ultraviolet‐B‐ (UV‐B‐) irradiated normal human dermal fibroblasts (NHDFs) by inhibiting nuclear factor‐κB p65 nuclear import and the resulting interleukin‐1β (IL‐1β) expression. To further elucidate the antiphotoaging potency of ETAS 50, we examined the anti‐inflammatory effects on UV‐B‐irradiated NHDFs by focusing on the stress‐activated mitogen‐activated protein kinase (MAPK) and Akt signaling pathways. NHDFs were treated with 1 mg/mL of ETAS 50 or dextrin (vehicle control) after UV‐B irradiation (20 mJ/cm²) for different time periods. Phosphorylation levels of c‐Jun N‐terminal kinase (JNK), p38 MAPK, and Akt were analyzed by western blotting. IL‐6 mRNA levels were analyzed by real‐time polymerase chain reaction. UV‐B‐irradiated NHDFs showed increased phosphorylation levels of JNK, p38 MAPK, and Akt, as well as increased mRNA levels of IL‐6. ETAS 50 treatment after UV‐B irradiation suppressed the increased phosphorylation levels of Akt without affecting those of JNK and p38 MAPK. ETAS 50 as well as Akt inhibitor Perifosine repressed UV‐B irradiation‐induced IL‐6 mRNA expression. These results suggest that ETAS 50 treatment represses UV‐B irradiation‐induced IL‐6 expression by suppressing Akt phosphorylation. The present findings demonstrate the potential of ETAS 50 to prevent photoaging by attenuating UV‐B irradiation‐induced proinflammatory responses in skin fibroblasts.

Ultraviolet (UV) irradiation induces proinflammatory responses in skin cells, including dermal fibroblasts, accelerating premature skin aging (photoaging). ETAS 50, a standardized extract from the Asparagus officinalis stem, is a novel and unique functional food that suppresses proinflammatory responses of hydrogen peroxide‐stimulated skin fibroblasts and interleukin‐ (IL‐) 1β‐stimulated hepatocytes. To elucidate its antiphotoaging potencies, we examined whether ETAS 50 treatment after UV‐B irradiation attenuates proinflammatory responses of normal human dermal fibroblasts (NHDFs). UV‐B‐irradiated NHDFs showed reduced levels of the cytosolic inhibitor of nuclear factor‐κB α (IκBα) protein and increased levels of nuclear p65 protein. The nuclear factor‐κB nuclear translocation inhibitor JSH‐23 abolished UV‐B irradiation‐induced IL‐1β mRNA expression, indicating that p65 regulates transcriptional induction. ETAS 50 also markedly suppressed UV‐B irradiation‐induced increases in IL‐1β mRNA levels. Immunofluorescence analysis revealed that ETAS 50 retained p65 in the cytosol after UV‐B irradiation. Western blotting also showed that ETAS 50 suppressed the UV‐B irradiation‐induced increases in nuclear p65 protein. Moreover, ETAS 50 clearly suppressed UV‐B irradiation‐induced distribution of importin‐α protein levels in the nucleus without recovering cytosolic IκBα protein levels. These results suggest that ETAS 50 exerts anti‐inflammatory effects on UV‐B‐irradiated NHDFs by suppressing the nuclear import machinery of p65. Therefore, ETAS 50 may prevent photoaging by suppressing UV irradiation‐induced proinflammatory responses of dermal fibroblasts.

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.

Moderate-intensity regular exercise improves proinflammatory responses of lipopolysaccharide- (LPS-) stimulated macrophages. However, intracellular events that mediate the beneficial effects of exercise were unclear. This study aimed to clarify the mechanism by which regular voluntary exercise (VE) improves proinflammatory cytokine production by macrophages challenged with LPS. Peritoneal macrophages from VE mice secreted considerably higher amounts of interleukin- (IL-) 1βand IL-18 than did cells from sedentary control (SC) mice in the presence and absence of LPS, although tumor necrosis factor-αand IL-10 secretion were comparable between both groups. The mRNA levels of these cytokines increased significantly in response to LPS; similar levels were noted in macrophages from both SC and VE mice. Moreover, LPS evoked similar levels of degradation of inhibitor ofκB (IκB)αand phosphorylation of IκB kinaseβ, c-Jun N-terminal kinase, and p38 in macrophages from SC and VE mice. These results indicate that the increased IL-1βand IL-18 secretion in VE mice are regulated posttranscriptionally. On the other hand, macrophages from VE mice showed higher amounts of caspase-1 protein than did cells from SC mice. These results suggest that regular VE potentiates IL-1βand IL-18 secretion in LPS-challenged macrophages by increasing caspase-1 levels.

Enzyme-treated asparagus extract (ETAS) exerts a wide variety of beneficial biological actions including facilitating anti-cortisol stress and neurological anti-aging responses. However, the anti-skin aging effects of ETAS remain to be elucidated. Reactive oxygen species (ROS) play pivotal roles in skin aging. Increased ROS levels in fibroblasts in response to ultraviolet irradiation activate c-Jun N-terminal kinase (JNK) and its downstream transcription factor activator protein-1 (AP-1), and the resultant gene expression of matrix metalloproteinase (MMP) isoforms accelerates collagen breakdown in the dermis. Therefore, we explored whether ETAS has anti-skin aging effects by attenuating the oxidative stress responses in fibroblasts. Simultaneous treatment of murine skin L929 fibroblasts with hydrogen peroxide (H₂O₂) and either ETAS or dextrin showed that ETAS significantly suppressed H₂O₂-induced expression of MMP-9 mRNA as measured by real-time polymerase chain reaction. ETAS also clearly suppressed H₂O₂-stimulated phosphorylation of c-Jun (AP-1 subunit) and JNK as determined by Western blot. However, ETAS did not affect the increased amounts of carbonyl proteins in response to H₂O₂, also as determined by Western blotting. These results suggest that ETAS diminishes cellular responsiveness to ROS but does not scavenge ROS. Thus, ETAS has the potential to prevent skin aging through attenuating the oxidative stress responses in dermal fibroblasts.

Recently, the ability of polyphenols to reduce the risk of dementia and Alzheimer's disease (AD) has attracted a great deal of interest. In the present study, we investigated the attenuating effects of oligomerised lychee fruit-derived polyphenol (OLFP, also called Oligonol) on early cognitive impairment. Male senescence-accelerated mouse prone 8 (SAMP8) mice (4 months old) were given OLFP (100 mg/kg per d) for 2 months, and then conditioned fear memory testing was conducted. Contextual fear memory, which is considered hippocampus-dependent memory, was significantly impaired in SAMP8 mice compared with non-senescence-accelerated mice. OLFP attenuated cognitive impairment in SAMP8 mice. Moreover, the results of real-time PCR analysis that followed DNA array analysis in the hippocampus revealed that, compared with SAMP8 mice, the mRNA expression of Wolfram syndrome 1 (Wfs1) was significantly higher in SAMP8 mice administered with OLFP. Wfs1 reportedly helps to protect against endoplasmic reticulum (ER) stress, which is thought to be one of the causes for AD. The expression of Wfs1 was significantly up-regulated in NG108-15 neuronal cells by the treatment with OLFP, and the up-regulation was inhibited by the treatment of the cells with a c-Jun N-terminal kinase-specific inhibitor rather than with an extracellular signal-regulated kinase inhibitor. Moreover, OLFP significantly attenuated the tunicamycin-induced expression of the ER stress marker BiP (immunoglobulin heavy chain-binding protein) in the cells. These results suggest that OLFP has an attenuating effect on early cognitive impairment in SAMP8 mice, and diminishes ER stress in neuronal cells.