High-fat Diet-induced Weight Gain Research Articles

Orobol, an Enzyme-Convertible Product of Genistein, exerts Anti-Obesity Effects by Targeting Casein Kinase 1 Epsilon

Soy isoflavones, particularly genistein, have been shown to exhibit anti-obesity effects. When compared with the isoflavones genistin, daidzin, coumestrol, genistein, daidzein, 6-o-dihydroxyisoflavone, equol, 3′-o-dihydroxyisoflavone, and 8-o-dihydroxyisoflavone, a remarkably higher inhibitory effect on lipid accumulation was observed for orobol treatment during adipogenesis in 3T3-L1 cells. To identify the cellular target of orobol, its pharmacological effect on 395 human kinases was analyzed. Of the 395 kinases, orobol showed the lowest half maximal inhibitory concentration (IC50) for Casein Kinase 1 epsilon (CK1ε), and bound to this target in an ATP-competitive manner. A computer modeling study revealed that orobol may potentially dock with the ATP-binding site of CK1ε via several hydrogen bonds and van der Waals interactions. The phosphorylation of eukaryotic translation initiation factor 4E-binding protein 1, a substrate of CK1ε, was inhibited by orobol in isobutylmethylxanthine, dexamethasone and insulin (MDI)-induced 3T3-L1 cells. It was also found that orobol attenuates high fat diet-induced weight gain and lipid accumulation without affecting food intake in C57BL/6J mice. These findings underline orobol’s potential for development as a novel agent for the prevention and treatment of obesity.

2492-PUB: KCNK16 Deficiency Protects Mice against High-Fat Diet-Induced Weight Gain

Potassium Channel, Two Pore Domain Subfamily K, Member 16 (TALK-1/KCNK16) is a K+ channel protein expressed in human and murine pancreas. Recent research by Vierra et al suggested a regulatory function of KCNK16 in mice for glucose-dependent β-cell second-phase insulin and δ-cell somatostatin secretion and a protective effect on fasting glycemia during 3 weeks high-fat diet (HFD). We tested the hypothesis, that deletion of KCNK16 affects body weight and glucose metabolism in vivo during prolonged HFD feeding. Therefore, we analyzed KCNK16-deficient knockout mice (KCNK16-/-) during HFD up to 21 weeks investigating body weight and composition, insulin sensitivity as well as insulin secretion. In HFD-fed KCNK16-/-, we observed a reduced body weight gain. Both, fat and lean mass were reduced and notably body-length was also significantly shorter. KCNK16-/- mice showed reduced food intake, an elevated oxygen consumption and energy expenditure. KCNK16-/- islets showed enhanced insulin secretion under glucose and GIP-1 simulation, but we did not reveal significant changes in fasting or fed plasma glucose or insulin. We found a moderate decrease in blood glucose during an ipITT. However, we did not observe an enhanced insulin sensitivity assessed by hyperinsulinemic-euglycemic clamps nor a beneficial effect of KCNK16 deficiency on the modulation of in vivo insulin secretion during hyperglycemic clamps in HFD-fed mice. In conclusion, we observed a reduced body weight gain, but also shorter body-length in the KCNK16-deficient mouse model during prolonged HFD feeding. Notably, food intake was reduced while energy expenditure was increased. Disclosure S. Brachs: Employee; Spouse/Partner; Treamid Therapeutics GmbH. Research Support; Self; Sanofi-Aventis Deutschland GmbH. U. Schwahn: Employee; Self; Sanofi-Aventis Deutschland GmbH. K. Steinmeyer: Employee; Self; Sanofi-Aventis Deutschland GmbH. M. Schäfer: Employee; Self; Sanofi-Aventis Deutschland GmbH. J. Gassenhuber: Employee; Self; Sanofi-Aventis Deutschland GmbH. Employee; Spouse/Partner; Sanofi-Aventis Deutschland GmbH. J. Spranger: None. Funding Sanofi Aventis Deutschland GmbH

Coenzyme Q10 Attenuates High-fat Diet-induced Non-alcoholic Fatty Liver Disease Through Activation of AMPK Pathway (P06-060-19)

ObjectivesTo explore whether CoQ10 has an effect on NAFLD and the potential mechanism. Methods2.1 Animal studies Thirty male C57BL/6 J mice (four weeks) were randomly distributed into three groups (n = 10): control group (10% Kcal from fat), the high-fat group (60% Kcal from fat), the CoQ10 group (CoQ10 1800 mg/kg, 60% Kcal from fat). The intervention time is 24 weeks.2.2 Biochemical indicator Serum and liver biochemical markers were detected with appropriate test kits.2.3 Histopathological evaluation H&E staining, immunohistochemistry and immunofluorescence were used to valuate the degree of NAFLD. Results3.1 CoQ10 ameliorates high-fat diet-induced weight gain and dyslipidaemia.CoQ10 decreased the weight gain (Fig. 1A). In addition, CoQ10 reduced the high-fat diet-induced subcutaneous and visceral fat. Serum levels of TC and TG decreased in mice fed HFD with supplementation of CoQ10 (Fig. 1C). The level of HDL-c showed an unremarkable increase in mice supplemented with CoQ10, while LDL-c in this group decreased (Fig. 1D).3.2 CoQ10 inhibited NAFLD induced by high-fat diet.The lipid droplet was reduced in the mice fed CoQ10(Fig. 2A). Analysis of Sirius Red staining showed that hepatic fibrosis was ameliorated in the mice fed CoQ10(Fig. 2B). Staining of macrophage marker, F4/80, and the leukocyte marker, CD45 showed that CoQ10 can alleviate inflammation(Fig.2C, D). CoQ10 also induce the injury of liver(Fig. 2E).3.3 CoQ10 regulates liver lipid metabolism.CoQ10 reversed the increase of ACC and FAS and reversed the decrease of PPAR-α and CPT-1 both in mRNA and protein expression. CoQ10 could activate AMPK. ConclusionsCo Q10 may attenuates high-fat diet-induced non-alcoholic fatty liver disease through activation of AMPK pathway. Funding SourcesThe key Project of National Natural Science Fund (grant number: 81730090). Supporting Tables, Images and/or Graphs▪▪▪

Brain serotonin in high-fat diet-induced weight gain, anxiety and spatial memory in rats

ABSTRACT Objectives: Effects of high-fat diet (HFD) consumption on body weight gain and its consequences on anxiety, learning and memory, and serotonin metabolism (5-hydroxytryptamine; 5-HT) in the hypothalamus and hippocampus are determined in rats. Methods: Male Wister rats treated with HFD or normal diet (ND) for 12 weeks to monitor food intakes, body weight changes, activity in an open field, anxiety in an elevated plus maze and learning/memory in Morris water maze. Animals decapitated to collect serum for determining leptin by an ELISA kit. The hippocampus and hypothalamus dissected out for determining 5-HT, its metabolite 5-hydroxyindoleacetic acid (5-HIAA) and its precursor tryptophan by HPLC-EC. Results: Despite a significant decrease in the cumulative weekly food intake, gain in body weight was greater in HFD than ND treated rats. Total caloric intakes were not different in the two groups. The consumption of HFD resulted in an enhancement of exploratory activity and reduction in anxiety. It improved learning acquisition and memory retention but impaired reference memory. There was an attenuation of 5-HT in the hypothalamus, and an enhancement of 5-HT and 5-HIAA in the hippocampus, but no effect occurred on tryptophan levels in the hypothalamus or the hippocampus. Serum leptin levels increased in HFD treated animals. Conclusion: Serotonin acting via the hypothalamus and hippocampus is involved in HFD-induced weight gain, anxiety reduction and modulation of cognitive performance.

Effects of combined glucocorticoid/mineralocorticoid receptor modulation (CORT118335) on energy balance, adiposity, and lipid metabolism in male rats.

Psychological stress and excess glucocorticoids are associated with metabolic and cardiovascular diseases. Glucocorticoids act primarily through mineralocorticoid (MR) and glucocorticoid receptors (GR), and compounds modulating these receptors show promise in mitigating metabolic and cardiovascular-related phenotypes. CORT118335 (GR/MR modulator) prevents high-fat diet-induced weight gain and adiposity in mice, but the ability of this compound to reverse obesity-related symptoms is unknown. Adult male rats were subcutaneously administered CORT118335 (3, 10, or 30 mg/kg) or vehicle once daily. A 5-day treatment with CORT118335 at 30 mg/kg induced weight loss in rats fed a chow diet by decreasing food intake. However, lower doses of the compound attenuated body weight gain primarily because of decreased calorific efficiency, as there were no significant differences in food intake compared with vehicle. Notably, the body weight effects of CORT118335 persisted during a 2-wk treatment hiatus, suggesting prolonged effects of the compound. To our knowledge, we are the first to demonstrate a sustained effect of combined GR/MR modulation on body weight gain. These findings suggest that CORT118335 may have long-lasting effects, likely due to GR/MR-induced transcriptional changes. Prolonged (18 days) treatment of CORT118335 (10 mg/kg) reversed body weight gain and adiposity in animals fed a high-fat diet for 13 wk. Surprisingly, this occurred despite a worsening of the lipid profile and glucose homeostasis as well as a disrupted diurnal corticosterone rhythm, suggesting GR agonistic effects in the periphery. We conclude that species and tissue-specific targeting may result in promising leads for exploiting the metabolically beneficial aspects of GR/MR modulation.

Neuregulin in Health and Disease.

The neuregulins Neuregulins, a family of EGF-like signaling molecules, are involved in cell-cell crosstalk and play an important role in development, maintenance and repair of the nervous system, heart, breast and other organs. Independent studies described a ligand for the oncogene ErbB2 (neu, Her2) and factors that stimulated proliferation of Schwann cells, as well as synthesis of receptors for acetylcholine by muscle. These ligands and factors are essentially products of the same gene, referred to by Marchionni M. as neuregulin (NRG-1) [1]. Besides NRG-1 gene, there are other genes that encode related proteins, such as NRG-2 (Don-1, NTAK), NRG-3 and NRG-4. There are few studies that describe NRG-2, −3 and −4 and a complete analysis of their function remains a challenge. However, NRG-2 was recently reported as a component of stress granules (SG), microscopically visible aggregates of translationally stalled messenger ribonucleoprotein complexes that are formed in response to direct stress conditions [2]. Furthermore, it was shown that NRG-2, secreted from astrocytes, bound to ErbB3 on neurons and promoted neuronal survival [3]. NRG-3 was shown to be associated with schizophrenia (SZ) in a Chinese population [4], with bipolar disorder (BD) [5] and with the risk and age of onset of Alzheimer disease (AD) [6]. In addition, NRG-3 has a key function in promoting early mammary morphogenesis and is involved in breast cancer (BC) [7]. NRG-4 expression was decreased in human inflammatory bowel disease samples and mouse models of colitis, suggesting that activation of ErbB4 is altered [8]. An interesting study [9] showed that NRG-4 overexpression prevents high fat diet-induced weight gain and fatty liver and reduces obesity-induced chronic inflammation. Considering the increasing interest and research focused on NRG-1 in the past years, this review summarizes what is currently known about NRG-1 and its impact on health and disease as well as its current and potential use(s) as a CNS anti-inflammatory agent against inducers of brain inflammation and injury as well as in the treatment of various neurological disorders. Neuregulin-1: Structure, function and signaling pathways: NRG-1 gene encodes 21 exons located on human chromosome 8p22–21. Alternative splicing of more than 30 exons in different parts of the NRG-1 transcript generates more than 30 isoforms that can be grouped into six types (I-VI) [10–12] (Figure 1). They are synthesized as transmembrane precursors consisting of either an immunoglobulin-like (Ig) domain or cysteine-rich domain (CRD), an EGF-like domain, a transmembrane domain and a cytoplasmic tail [13]. NRG-1 types I and II are released from the cell surface after protease-mediated proteolytic cleavage and may function as paracrine signals [14]. NRG-1 type III remains tethered to the cell membrane after cleavage and acts as a juxtacrine signal [15]. Full-length type IV spans 1.8 kb and encodes a putative protein of 590 amino acids with a predicted molecular mass of approximately 66 kDa [15]. Further-more, there are two major classes of NRG-1 identified as α and β isoforms. NRG-1α and NRG-1β contain related, but structurally distinct EGF-like domains composed of a common amino terminal segment followed by α or β variant sequences [16]. NRG-1β isoforms predominate in the nervous system while α isoforms are common in mesenchymal cells and are critically important for breast development [14]. Type I NRGα and β isoforms are the predominant isoforms expressed in early embryogenesis, whereas type II and type III are undetectable until the mid-gestation stage [17]. Type I or Heregulin is an acetylcholine receptor activator, type II is a Glial Growth Factor, type III is a sensory and motor neuron-derived factor and type IV is involved in neuronal activity regulation. Functions of types V and VI are not well known and their investigation remains a challenge. Types I, II and III of NRG-1 express in human peripheral blood in addition to neurons, while types IV and V express specifically in the brain [18]. Open in a separate window Figure 1: Neuregulin (NRG) and ErbB receptor structures. NRG gene products share a structural characteristic for the extracellular epidermal growth factor (EGF) domain and it differentiates this subfamily from other members of the EGF family. All EGF family members are ligands of ErbB receptors, although with varying affinities, with ErbB3 and ErbB4 being specific NRG-binding receptors. NRG-1 isoforms have been classified in types I-VI on the basis of differences in the NH2-terminal distal region [19].

Binding Efficacy and Thermogenic Efficiency of Pungent and Nonpungent Analogs of Capsaicin.

(1) Background: Capsaicin, a chief ingredient of natural chili peppers, enhances metabolism and energy expenditure and stimulates the browning of white adipose tissue (WAT) and brown fat activation to counter diet-induced obesity. Although capsaicin and its nonpungent analogs are shown to enhance energy expenditure, their efficiency to bind to and activate their receptor—transient receptor potential vanilloid subfamily 1 (TRPV1)—to mediate thermogenic effects remains unclear. (2) Methods: We analyzed the binding efficiency of capsaicin analogs by molecular docking. We fed wild type mice a normal chow or high fat diet (± 0.01% pungent or nonpungent capsaicin analog) and isolated inguinal WAT to analyze the expression of thermogenic genes and proteins. (3) Results: Capsaicin, but not its nonpungent analogs, efficiently binds to TRPV1, prevents high fat diet-induced weight gain, and upregulates thermogenic protein expression in WAT. Molecular docking studies indicate that capsaicin exhibits the highest binding efficacy to TRPV1 because it has a hydrogen bond that anchors it to TRPV1. Capsiate, which lacks the hydrogen bond, and therefore, does not anchor to TRPV1. (4) Conclusions: Long-term activation of TRPV1 is imminent for the anti-obesity effect of capsaicin. Efforts to decrease the pungency of capsaicin will help in advancing it to mitigate obesity and metabolic dysfunction in humans.

Intestinal epithelial cell-specific Raptor is essential for high fat diet-induced weight gain in mice

Mammalian target of rapamycin complex 1 (mTORC1) is a major regulator of cell growth and proliferation through fuel sensing. Systemic inhibition of mTOR as well as manipulation of its downstream products prevent diet-induced obesity. The purpose of this study was to determine the consequences of intestine-targeted mTORC1 inhibition. To attenuate intestinal mTORC1 activity, Villin-CreER mice were crossed with Raptorflox/flox mice, creating an intestinal-specific Raptor null line (i-Raptor −/−). Mice were fed a high fat diet (HFD) and compositional changes as well as food intake levels were assessed. Over a five-week time course, i-Raptor −/− mice consistently gained less body weight on a HFD compared to wildtype (WT) mice secondary to significantly reduced food intake. Importantly, the i-Raptor −/− mice did not appear to be malnourished, demonstrated by their preservation of lean body mass. i-Raptor −/− mice also maintained a normal metabolic profile without significant changes in triglyceride or fasting glucose levels. Further investigation revealed that GDF-15 mRNA expression was significantly enhanced in i-Raptor −/− enterocytes when refed with HFD after overnight starvation. In summary, our study establishes that loss of intestinal specific-mTORC1 is protective of the development of diet-induced obesity by reducing food intake without altering the metabolic profile.

Decrease in αβ/γδ T-cell ratio is accompanied by a reduction in high-fat diet-induced weight gain, insulin resistance, and inflammation.

The implication of αβ and γδ T cells in obesity-associated inflammation and insulin resistance (IR) remains uncertain. Mice lacking γδ T cells show either no difference or a decrease in high-fat diet (HFD)-induced IR, whereas partial depletion in γδ T cells does not protect from HFD-induced IR. αβ T-cell deficiency leads to a decrease in white adipose tissue (WAT) inflammation and IR without weight change, but partial depletion of these cells has not been studied. We previously described a mouse model overexpressing peroxisome proliferator-activated receptor β (PPAR-β) specifically in T cells [transgenic (Tg) T-PPAR-β] that exhibits a partial depletion in αβ T cells and no change in γδ T-cell number. This results in a decreased αβ/γδ T-cell ratio in lymphoid organs. We now show that Tg T-PPAR-β mice are partially protected against HFD-induced weight gain and exhibit decreased IR and liver steatosis independently of animal weight. These mice display an alteration of WAT-depots distribution with an increased epididymal-WAT mass and a decreased subcutaneous WAT mass. Immune cell number is decreased in both WAT-depots, except for γδ T cells, which are increased in epididymal-WAT. Overall, we show that decreasing αβ/γδ T-cell ratio in WAT-depots alters their inflammatory state and mass repartition, which might be involved in improvement of insulin sensitivity.-Le Menn, G., Sibille, B., Murdaca, J., Rousseau, A.-S., Squillace, R., Vergoni, B., Cormont, M., Niot, I., Grimaldi, P. A., Mothe-Satney, I., Neels, J. G. Decrease in αβ/γδ T-cell ratio is accompanied by a reduction in high-fat diet-induced weight gain, insulin resistance, and inflammation.

Increased bone mass in a mouse model with low fat mass.

Mice with impaired acute inflammatory responses within adipose tissue display reduced diet-induced fat mass gain associated with glucose intolerance and systemic inflammation. Therefore, acute adipose tissue inflammation is needed for a healthy expansion of adipose tissue. Because inflammatory disorders are associated with bone loss, we hypothesized that impaired acute adipose tissue inflammation leading to increased systemic inflammation results in a lower bone mass. To test this hypothesis, we used mice overexpressing an adenoviral protein complex, the receptor internalization and degradation (RID) complex that inhibits proinflammatory signaling, under the control of the aP2 promotor (RID tg mice), resulting in suppressed inflammatory signaling in adipocytes. As expected, RID tg mice had lower high-fat diet-induced weight and fat mass gain and higher systemic inflammation than littermate wild-type control mice. Contrary to our hypothesis, RID tg mice had increased bone mass in long bones and vertebrae, affecting trabecular and cortical parameters, as well as improved humeral biomechanical properties. We did not find any differences in bone formation or resorption parameters as determined by histology or enzyme immunoassay. However, bone marrow adiposity, often negatively associated with bone mass, was decreased in male RID tg mice as determined by histological analysis of tibia. In conclusion, mice with reduced fat mass due to impaired adipose tissue inflammation have increased bone mass.

The structure of human Nocturnin reveals a conserved ribonuclease domain that represses target transcript translation and abundance in cells.

The circadian protein Nocturnin (NOCT) belongs to the exonuclease, endonuclease and phosphatase superfamily and is most similar to the CCR4-class of deadenylases that degrade the poly-adenosine tails of mRNAs. NOCT-deficient mice are resistant to high-fat diet induced weight gain, and exhibit dysregulation of bone formation. However, the mechanisms by which NOCT regulates these processes remain to be determined. Here, we describe a pair of high-resolution crystal structures of the human NOCT catalytic domain. The active site of NOCT is highly conserved with other exoribonucleases, and when directed to a transcript in cells, NOCT can reduce translation and abundance of that mRNA in a manner dependent on key active site residues. In contrast to the related deadenylase CNOT6L, purified recombinant NOCT lacks in vitro ribonuclease activity, suggesting that unidentified factors are necessary for enzymatic activity. We also find the ability of NOCT to repress reporter mRNAs in cells depends upon the 3′ end of the mRNA, as reporters terminating with a 3′ MALAT1 structure cannot be repressed by NOCT. Together, these data demonstrate that NOCT is an exoribonuclease that can degrade mRNAs to inhibit protein expression, suggesting a molecular mechanism for its regulatory role in lipid metabolism and bone development.

Dietary mung bean protein reduces high-fat diet-induced weight gain by modulating host bile acid metabolism in a gut microbiota-dependent manner

The 8-globulin-rich mung bean protein (MPI) suppresses hepatic lipogenesis in rodent models and reduces fasting plasma glucose and insulin levels in obese adults. However, its effects on mitigating high fat diet (HFD)-induced obesity and the mechanism underlying these effects remain to be elucidated. Herein, we examined the metabolic phenotype, intestinal bile acid (BA) pool, and gut microbiota of conventionally raised (CONV-R) male C57BL/6 mice and germ-free (GF) mice that were randomized to receive either regular HFD or HFD containing mung bean protein isolate (MPI) instead of the dairy protein present in regular HFD. MPI intake significantly reduced HFD-induced weight gain and adipose tissue accumulation, and attenuated hepatic steatosis. Enhancement in the secretion of intestinal glucagon-like peptide-1 (GLP-1) and an enlarged cecal and fecal BA pool of dramatically elevated secondary/primary BA ratio were observed in mice that had consumed MPI. These effects were abolished in GF mice, indicating that the effects were dependent upon the presence of the microbiota. As revealed by 16S rRNA gene sequence analysis, MPI intake also elicited dramatic changes in the gut microbiome, such as an expansion of taxa belonging to the phylum Bacteroidetes along with a reduced abundance of the Firmicutes.

Tpcn2 knockout mice have improved insulin sensitivity and are protected against high-fat diet-induced weight gain.

Type 2 diabetes is a complex disorder affected by multiple genes and the environment. Our laboratory has shown that in response to a glucose challenge, two-pore channel 2 ( Tpcn2) knockout mice exhibit a decreased insulin response but normal glucose clearance, suggesting they have improved insulin sensitivity compared with wild-type mice. We tested the hypothesis that improved insulin sensitivity in Tpcn2 knockout mice would protect against the negative effects of a high fat diet. Male and female Tpcn2 knockout (KO), heterozygous (Het), and wild-type (WT) mice were fed a low-fat (LF) or high-fat (HF) diet for 24 wk. HF diet significantly increases body weight in WT mice relative to those on the LF diet; this HF diet-induced increase in body weight is blunted in the Het and KO mice. Despite the protection against diet-induced weight gain, however, Tpcn2 KO mice are not protected against HF-diet-induced changes in glucose or insulin area under the curve during glucose tolerance tests in female mice, while HF diet has no significant effect on glucose tolerance in the male mice, regardless of genotype. Glucose disappearance during an insulin tolerance test is augmented in male KO mice, consistent with our previous findings suggesting enhanced insulin sensitivity in these mice. Male KO mice exhibit increased fasting plasma total cholesterol and triglyceride concentrations relative to WT mice on the LF diet, but this difference disappears in HF diet-fed mice where there is increased cholesterol and triglycerides across all genotypes. These data demonstrate that knockout of Tpcn2 may increase insulin action in male, but not female, mice. In addition, both male and female KO mice are protected against diet-induced weight gain, but this protection is likely independent from glucose tolerance, insulin sensitivity, and plasma lipid levels.

Abstract 700: Adipocyte-Specific Calpain-2 Deficiency Attenuates Obesity-accelerated Abdominal Aortic Aneurysms in Mice

Background and Objective: Recent clinical studies demonstrated that abdominal adiposity is associated with increased risk of abdominal aortic aneurysm (AAA) development. Calpains are non-lysosomal calcium dependent cysteine proteases that are highly expressed in human and experimental AAAs. Using a pharmacological inhibitor and genetically deficient mice, we identified that calpain-2 (a major ubiquitous isoform) plays a critical role in Angiotensin II (AngII)-induced AAA formation in obese mice. In addition, we demonstrated that calpain inhibition strongly suppressed adipose tissue inflammation in obese mice. The purpose of this study was to determine the role of adipocyte-specific calpain-2 on obesity-accelerated AAA. Methods and Results: Calpain-2 floxed mice that were hemizygous for Adiponectin Cre (Cre+/0) were produced by breeding male Cre+/0 to female calpain-2 floxed mice. Littermates that were homozygous for the floxed calpain-2 gene, but without the Cre transgene (Cre0/0), were used as control mice. Western blot analyses showed that calpain-2 protein is depleted in various fat tissues including periaortic adipose, from Cre+/0 mice, while not influencing abundance in aorta and other tissues. Male Cre+/0 and Cre0/0 mice were fed a high fat diet (60% Kcal) for 20 weeks. After 16 weeks of diet feeding, mice (n=20-22) were infused with either saline or AngII (1,000 ng/kg/min) by osmotic minipumps for 4 weeks. Depletion of calpain-2 in adipocytes had no effect on high fat diet-induced body weight gain, fat mass, glucose and insulin tolerance. Interestingly, adipocyte-specific calpain-2 depletion significantly attenuated AngII-induced expansion of ex-vivo maximal diameter of abdominal aortas in obese mice (Saline- Cre0/0: 0.95 ± 0.03; Cre+/0: 0.98 ± 0.02 mm; AngII - Cre0/0: 1.95 ± 0.20; Cre+/0: 1.25 ± 0.08 mm P<0.001). In addition, calpain-2 depletion also reduced the incidence of AngII-induced AAAs in mice (Cre0/0: 76% versus Cre+/0: 27%). Conclusion: These findings suggest that adipocyte-derived calpain-2 plays a critical role in AngII-induced AAA development in diet-induced obese mice.

High-fat diet exacerbates postoperative pain and inflammation in a sex-dependent manner.

Obesity is often associated with increased pain, but little is known about the effects of obesity and diet on postoperative pain. In this study, effects of diet and obesity were examined in the paw incision model, a preclinical model of postoperative pain. Long-Evans rats were fed high-fat diet (40% calories from butter fat) or low-fat normal chow. Male rats fed high-fat diet starting 6 weeks before incision (a diet previously shown to induce markers of obesity) had prolonged mechanical hypersensitivity and an overall increase in spontaneous pain in response to paw incision, compared with normal chow controls. Diet effects in females were minor. Removing high-fat diet for 2 weeks before incision reversed the diet effects on pain behaviors, although this was not enough time to reverse high-fat diet-induced weight gain. A shorter (1 week) exposure to high-fat diet before incision also increased pain behaviors in males, albeit to a lesser degree. The 6-week high-fat diet increased macrophage density as examined immunohistochemically in lumbar dorsal root ganglion even before paw incision, especially in males, and sensitized responses of peritoneal macrophages to lipopolysaccharide stimuli in vitro. The nerve regeneration marker growth-associated protein 43 (GAP43) in skin near the incision (day 4) was higher in the high-fat diet group, and wound healing was delayed. In summary, high-fat diet increased postoperative pain particularly in males, but some diet effects did not depend on weight gain. Even short-term dietary manipulations, that do not affect obesity, may enhance postoperative pain.

4-hydroxy-3-methoxycinnamic acid regulates orexigenic peptides and hepatic glucose homeostasis through phosphorylation of FoxO1

4-hydroxy-3-methoxycinnamic acid (ferulic acid, FA) is known to have numerous beneficial health effects, including anti-obesity and anti-hyperglycemic properties. However, the molecular networks that modulate the beneficial FA-induced metabolic effects have not been well elucidated. In this study, we explored the molecular mechanisms mediating the beneficial metabolic effects of FA. In mice, FA protected against high-fat diet-induced weight gain, reduced food intake and exhibited an overall improved metabolic phenotype. The food intake suppression by FA was accompanied by a specific reduction in hypothalamic orexigenic neuropeptides, including agouti-related protein and neuropeptide Y, with no significant changes in the anorexigenic peptides pro-opiomelanocortin and cocaine and amphetamine-regulated transcript. FA treatment also inhibited fat accumulation in the liver and white adipose tissue and suppressed the expression of gluconeogenic genes, including phosphoenolpyruvate carboxylase and glucose-6-phosphatase. Furthermore, we show that FA phosphorylated and inactivated the transcription factor FoxO1, which positively regulates the expression of gluconeogenic and orexigenic genes, providing evidence that FA might exert its beneficial metabolic effects through inhibition of FoxO1 function in the periphery and the hypothalamus.

지방분화가 유도된 3T3-L1 세포와 고지방식이로 유도된 마우스에서 보리순 물추출물의 항비만 효과

Background: An imbalance in energy intake and expenditure can cause obesity, which is a major risk factor for chronic diseases such as heart disease, type 2 diabetes, insulin resistance, cancers and hyperlipidemia.Methods and Results: In this study, we evaluated the anti-obesity effects of a water extract from the young leaves of barley sprout (BS) in 3T3-L1 cells and in high-fat diet (HFD)-induced obese mice (HF). Lipid accumulation measurement indicates that BS markedly inhibited adipogenesis by reducing lipid droplet production in a dose-dependent manner. Furthermore, the mRNA expression of adipogenic transcription factors peroxisome proliferator-activated receptor-γ and fatty acid synthetase, CCAAT/enhancer binding protein-α and fatty acid binding protein 4 in 3T3-L1 cells was significantly inhibited by BS treatment. In an in vivo test, the BSadministered group of HFD-induced mice showed less body weight gain, and lower liver and epididymal white adipose tissue weights. The BS-treated mice showed decreased serum levels of leptin and lipids compared to untreated HFD mice and the levels of adiponectin and the HDL-cholesterol/total cholesterol ratio increased. These results indicate that BS inhibits body fat accumulation by reducing the mRNA expression of lipogenesis transcription factors and increasing serum adipokine concentration in in vitro and in vivo tests.Conclusions: BS reduced high fat diet-induced weight gain and had a positive effect on dyslipidemia.

Exposure to permethrin promotes high fat diet-induced weight gain and insulin resistance in male C57BL/6J mice

Permethrin is a pyrethroid pesticide that was previously reported to promote fat accumulation and insulin resistance in vitro. A recent study in female mice also found that permethrin could promote high fat-induced insulin resistance. The effects of permethrin on glucose and lipid metabolisms in male mice, however, remain unknown. The purpose of this study was to investigate the effects and interactions of permethrin exposure (50, 500, and 5000 μg/kg body weight/day) and dietary fat (low fat, 4% w/w; high fat, 20% w/w) on development of obesity and insulin resistance in male C57BL/6J mice. Our results showed that permethrin treatment significantly increased body weight, fat mass, and insulin resistance with high fat diet, but not with low fat diet, without influencing energy intake. Permethrin treatment also significantly increased serum levels of insulin, glucose, leptin, triglycerides and cholesterol. Further results showed that permethrin inhibited AMP-activated protein kinase in white adipose tissue. These results suggest that permethrin interacts with dietary fat to alter lipid and glucose metabolisms in male C57BL/6J mice.

Stress-responsive FKBP51 regulates AKT2-AS160 signaling and metabolic function

The co-chaperone FKBP5 is a stress-responsive protein-regulating stress reactivity, and its genetic variants are associated with T2D related traits and other stress-related disorders. Here we show that FKBP51 plays a role in energy and glucose homeostasis. Fkbp5 knockout (51KO) mice are protected from high-fat diet-induced weight gain, show improved glucose tolerance and increased insulin signaling in skeletal muscle. Chronic treatment with a novel FKBP51 antagonist, SAFit2, recapitulates the effects of FKBP51 deletion on both body weight regulation and glucose tolerance. Using shorter SAFit2 treatment, we show that glucose tolerance improvement precedes the reduction in body weight. Mechanistically, we identify a novel association between FKBP51 and AS160, a substrate of AKT2 that is involved in glucose uptake. FKBP51 antagonism increases the phosphorylation of AS160, increases glucose transporter 4 expression at the plasma membrane, and ultimately enhances glucose uptake in skeletal myotubes. We propose FKBP51 as a mediator between stress and T2D development, and potential target for therapeutic approaches.

Serine prevented high-fat diet-induced oxidative stress by activating AMPK and epigenetically modulating the expression of glutathione synthesis-related genes

Serine deficiency has been observed in patients with nonalcoholic fatty liver disease (NAFLD). Whether serine supplementation has any beneficial effects on the prevention of NAFLD remains unknown. The present study was conducted to investigate the effects of serine supplementation on hepatic oxidative stress and steatosis and its related mechanisms. Forty male C57BL/6J mice (9week-old) were randomly assigned into four groups (n=10) and fed: i) a low-fat diet; ii) a low-fat diet supplemented with 1% (wt:vol) serine; iii) a high-fat (HF) diet; and iv) a HF diet supplemented with 1% serine, respectively. Palmitic acid (PA)-treated primary hepatocytes separated from adult mice were also used to study the effects of serine on oxidative stress. The results showed that serine supplementation increased glucose tolerance and insulin sensitivity, and protected mice from hepatic lipid accumulation, but did not significantly decreased HF diet-induced weight gain. In addition, serine supplementation protected glutathione (GSH) antioxidant system and prevented hypermethylation in the promoters of glutathione synthesis-related genes, while decreasing reactive oxygen species (ROS) in mice fed a HF diet. Moreover, we found that serine supplementation increased phosphorylation and S-glutathionylation of AMP-activated protein kinase α subunit (AMPKα), and decreased ROS, malondialdehyde and triglyceride contents in PA-treated primary hepatocytes. However, while AMPK activity or GSH synthesis was inhibited, the abovementioned effects of serine on PA-treated primary hepatocytes were not observed. Our results suggest that serine supplementation could prevent HF diet-induced oxidative stress and steatosis by epigenetically modulating the expression of glutathione synthesis-related genes and through AMPK activation.