Wheat alkylresorcinol increases fecal lipid excretion and suppresses feed efficiency in mice depending on time of supplementation.

OBJECTIVE: The regular consumption of whole grains is linked to a lower likelihood of developing metabolic disorders. We previously found that chronic supplementation with wheat alkylresorcinols (ARs) prevents obesity and its associated metabolic symptoms induced by a high-fat high-sucrose diet (HFHSD) in mice. The aim of this study was to examine the time-of-day-dependence of these effects in mice. METHODS: Eight-wk-old male C57 BL/6 J mice were individually housed under a 12-h light/dark cycle (Zeitgeber time; ZT0, lights on; ZT12, lights off) and given access to a HFHSD from ZT12-16 (activity onset) and ZT20-24 (activity offset) to respectively represent breakfast and dinner times for 3 wk. Thereafter, the HFHSD was replaced with the same diet containing 0.4% ARs at either ZT12-16 or ZT20-24 for 8 wk. Control mice received the HFHSD without ARs at both feeding times. RESULTS: Supplementation with ARs significantly suppressed feed efficiency when given at breakfast, but not at dinner. ARs consumed at breakfast increased fecal lipid content and decreased the expression of Fat/Cd36 in enterocytes that enhances lipid uptake, but did not affect hepatic and blood lipid levels. The consumption of ARs at breakfast also upregulated the expression of Irs1, a key gene for insulin signaling in white adipose tissue and attenuated elevated blood leptin levels induced by the diet. This led to high scores for the homeostasis model assessment of insulin sensitivity, and the adiponectin/leptin ratio, a negative index of adipose tissue dysfunction. CONCLUSIONS: These findings suggested that ARs ameliorate feed efficiency by decreasing dietary lipid absorption more effectively at the time of activity onset than offset. Further studies are needed to elucidate the molecular mechanism of the time-of-day-dependent effects of ARs on diet-induced metabolic disorders.

Acute Effects of Transdermal Administration of Jojoba Oil on Lipid Metabolism in Mice.

Background and objectives: Aroma therapy is a complementary therapy using essential oils diluted with carrier oils. Jojoba oils have been widely used as carrier oils. However, limited information is available regarding their effects on blood biochemical parameters. This study aimed to investigate the effect of transdermal administration of jojoba oil on blood biochemical parameters in mice. Materials and Methods: Eight-week-old male hairless mice were randomly divided into naïve control and treatment groups. In the treatment group, mice were topically administered 4 µL of jojoba oil, per gram of body weight, on the dorsa 30 min before euthanasia. Thereafter, serum biochemical parameters were assayed, and gene expression was analyzed in various tissues via a real-time polymerase chain reaction. Results: Serum non-esterified fatty acid (NEFA) levels increased significantly 30 min after topical application of jojoba oil (p < 0.05). Atgl was significantly upregulated in the liver (p < 0.05), and Atgl upregulation in the liver was positively correlated with serum NEFA levels (r = 0.592, p < 0.05). Furthermore, a trend of decreasing fatty acid trafficking-related gene (FABPpm, FATP-1, FATP-3, and FATP-4) expression in the skin after topical application of jojoba oil (p = 0.067, 0.074, 0.076, and 0.082, respectively) was observed. Conclusions: Serum NEFA levels were elevated 30 min after transdermal administration of jojoba oil. The mechanisms of elevated serum NEFA levels might be related to both enhanced lipolysis in the liver and reduced fatty acid trafficking in the skin.

Reduced skin lipid content in obese Japanese women mediated by decreased expression of rate-limiting lipogenic enzymes.

Skin barrier function is often deficient in obese individuals, but the underlying molecular mechanisms remain unclear. This study investigated how skin structure and lipid metabolism, factors strongly associated with barrier function, differed among 50 Japanese women of greatly varying body mass index (BMI). Subjects receiving breast reconstruction surgery were chosen for analysis to obtain skin samples from the same site. The subjects were classified into two groups, control (BMI < 25 kg/m2) and obese (25 kg/m2 ≤ BMI < 35 kg/m2), according to standards in Japan. Hematoxylin and eosin staining was used to assess skin thickness, Ki-67 immunostaining to examine keratinocyte proliferation, and real-time polymerase chain reaction to measure skin expression levels of genes associated with lipid metabolism. Total lipids, cholesterol, and fatty acids were also measured from these same skin samples. In the obese group, structural changes included epidermal thickening and an increase in the number of Ki-67-positive (proliferating) cells. Both skin cholesterol and fatty acid levels exhibited an "inverted-U" relationship with BMI, suggesting that there is an optimal BMI for peak lipid content and barrier function. Decreased lipid levels at higher BMI were accompanied by downregulated expression of PPARδ and other genes related to lipid metabolism, including those encoding acetyl-CoA carboxylase and HMG-CoA reductase, the rate-limiting enzymes for fatty acid and cholesterol synthesis, respectively. Thus, elevated BMI may lead to deficient skin barrier function by suppressing local lipid synthesis.

Efficacy of Kaempferia parviflora in a mouse model of obesity-induced dermatopathy.

Obesity results from excessive energy intake and physical inactivity, and predisposes one to various diseases. One of these reasons is that enlargement of adipocytes raises the lipid metabolic abnormalities that affect various organs. The skin is one such organ, and it has been reported that subcutaneous adipocyte cells secrete various factors and these factors are involved in reduction of dermal collagen fibers and fragility of the skin in obesity. The present study explored the efficacy of Kaempferia parviflora (KP) in preventing obesity-induced dermatopathy. We used Tsumura Suzuki obese diabetes (TSOD) mice as an obesity model. TSOD mice were fed a standard diet (MF) mixed with either an ethanol extract from KP (KPE), polymethoxyflavonoid-rich extract from KP (PMF), or polymethoxyflavonoid-poor extract from KP (X). We then evaluated the effect of these three KP fractions on aging-like skin damage induced by UVB irradiation. KPE and PMF caused a significant decrease of mouse body weight, and suppressed the increase in the thickness of the subcutaneous fat layer. In addition, KPE shifted the frequency of subcutaneous adipocyte sizes towards smaller cells possibly via its polypharmacological actions. Scanning electron microscopy revealed that the stereostructure of the collagenous fibers in the dermis was better retained in the KPE and PMF groups, in that order. These results offer the first evidence that KPE can attenuate obesity-induced dermatopathy more effectively than PMF, suggesting that KPE (or KP) might be a candidate supplement for preventing obesity-related skin disorders.

Attenuated food anticipatory activity and abnormal circadian locomotor rhythms in Rgs16 knockdown mice.

Regulators of G protein signaling (RGS) are a multi-functional protein family, which functions in part as GTPase-activating proteins (GAPs) of G protein α-subunits to terminate G protein signaling. Previous studies have demonstrated that the Rgs16 transcripts exhibit robust circadian rhythms both in the suprachiasmatic nucleus (SCN), the master circadian light-entrainable oscillator (LEO) of the hypothalamus, and in the liver. To investigate the role of RGS16 in the circadian clock in vivo, we generated two independent transgenic mouse lines using lentiviral vectors expressing short hairpin RNA (shRNA) targeting the Rgs16 mRNA. The knockdown mice demonstrated significantly shorter free-running period of locomotor activity rhythms and reduced total activity as compared to the wild-type siblings. In addition, when feeding was restricted during the daytime, food-entrainable oscillator (FEO)-driven elevated food-anticipatory activity (FAA) observed prior to the scheduled feeding time was significantly attenuated in the knockdown mice. Whereas the restricted feeding phase-advanced the rhythmic expression of the Per2 clock gene in liver and thalamus in the wild-type animals, the above phase shift was not observed in the knockdown mice. This is the first in vivo demonstration that a common regulator of G protein signaling is involved in the two separate, but interactive circadian timing systems, LEO and FEO. The present study also suggests that liver and/or thalamus regulate the food-entrained circadian behavior through G protein-mediated signal transduction pathway(s).

Acute induction of Eya3 by late-night light stimulation triggers TSHß expression in photoperiodism.

Living organisms detect seasonal changes in day length (photoperiod) [1-3] and alter their physiological functions accordingly to fit seasonal environmental changes. TSHß, induced in the pars tuberalis (PT), plays a key role in the pathway that regulates vertebrate photoperiodism [4, 5]. However, the upstream inducers of TSHß expression remain unknown. Here we performed genome-wide expression analysis of the PT under chronic short-day and long-day conditions in melatonin-proficient CBA/N mice, in which the photoperiodic TSHß expression response is preserved [6]. This analysis identified "short-day" and "long-day" genes, including TSHß, and further predicted the acute induction of long-day genes by late-night light stimulation. We verified this by advancing and extending the light period by 8 hr, which induced TSHß expression within one day. In the following genome-wide expression analysis under this acute long-day condition, we searched for candidate upstream genes by looking for expression that preceded TSHß's, and we identified the Eya3 gene. We demonstrated that Eya3 and its partner Six1 synergistically activate TSHß expression and that this activation is further enhanced by Tef and Hlf. These results elucidate the comprehensive transcriptional photoperiodic response in the PT, revealing the complex regulation of TSHß expression and unexpectedly rapid response to light changes in the mammalian photoperiodic system.

Reduced food anticipatory activity in genetically orexin (hypocretin) neuron-ablated mice.

Daily restricted feeding (RF) produces an anticipatory locomotor activity rhythm and entrains the peripheral molecular oscillator independently of the central pacemaker located in the suprachiasmatic nucleus (SCN). As orexins (hypocretins) are neuropeptides that coordinate sleep/wake patterns and motivated behaviours, such as food seeking, we studied the involvement of orexin in the food anticipatory activity (FAA) induced by RF. Daily RF shifted the mRNA rhythm of a clock-controlled gene mDbp in the cerebral cortex and caudate putamen but not in the SCN. Under these experimental conditions, prepro-orexin mRNA and orexin A immunoreactivity in the lateral hypothalamic area (LHA) did not show daily variation. Fasting increased the number of orexin A-ir cells, while RF did not. However, RF shifted the peak of Fos expression of the orexin neurons from night to day. Genetic ablation of orexin neurons in orexin/ataxin-3 transgenic mice severely reduced the formation of FAA under RF conditions. The expression of mNpas2 mRNA, a transcription factor thought to be involved in regulation of the food entrainable oscillator as well as mPer1 and mBmal1 mRNA, was reduced in the forebrain of orexin/ataxin-3 mice. Based on these results, we suggest that activity of the orexin neuron in the LHA contributes to the promotion and maintenance of FAA.

Ca2+/calmodulin-dependent protein kinase II-dependent long-term potentiation in the rat suprachiasmatic nucleus and its inhibition by melatonin.

We recently reported that Ca(2+)/calmodulin-dependent protein (CaM) kinase II is involved in light-induced phase delays and Per gene induction in the suprachiasmatic nucleus (SCN). To clarify the activation mechanisms of CaM kinase II by glutamate receptor stimulation in the SCN, we documented CaM kinase II activation following induction of long-term potentiation (LTP) in the rat SCN. High-frequency stimulation (100 Hz, 1 sec) applied to the optic nerve resulted in LTP of a postsynaptic field potential in the rat SCN. Unlike LTP in the hippocampal CA1 region, LTP onset in the SCN was slow and partly dependent on N-methyl-D-aspartate receptor activation. LTP induction in the SCN was completely inhibited by treatment with a nitric oxide synthase inhibitor or with a specific CaM kinase II inhibitor. Immunoblotting analysis using phosphospecific antibodies against autophosphorylated CaM kinase II revealed that LTP induction was accompanied by an increase in autophosphorylation. After high-frequency stimulation, we could visualize activation of CaM kinase II in vasoactive intestinal polypeptide-positive neurons in the SCN by immunohistochemistry. Treatment with cyclosporin A, a calcineurin inhibitor, potentiated LTP induction in the rat SCN. Interestingly, treatment with melatonin totally prevented LTP induction, without changes in basal synaptic transmission. Analyses of phosphorylation of CaM kinase II, mitogen-activated protein kinase, and cAMP-responsive element binding protein revealed that stimulatory and inhibitory effects on CaM kinase II autophosphorylation underlie the effects of cyclosporin A and melatonin, respectively. These results suggest that CaM kinase II plays critical roles in LTP induction in the SCN and that melatonin has inhibitory effects on synaptic plasticity through CaM kinase II.