Gene expression profiling of adipocyte and stromal vascular cells from adipose tissue in lean, obese and formerly obese mice
ABSTRACT: To investigate the transcriptional profiles of adipocytes and stromal vascular cells from mouse visceral adipose tissue(vWAT) in lean (Low fat diet, LFD fed), obese (high fat diet, HFD fed) and formerly obese (diet switch (SW) from 9 weeks HFD, to 3 weeks LFD) to induce weight loss.
Project description:Clinical studies indicate alternate-day, intermittent fasting (IMF) protocols result in meaningful weight loss in obese individuals. To further understand the mechanisms sustaining weight loss by IMF, we investigated the metabolic and neural alterations of IMF in obese mice. Male C57/BL6 mice were fed a high-fat diet (HFD; 45% fat) ad libitum for 8 weeks to promote an obese phenotype. Mice were divided into four groups and either maintained on ad libitum HFD, received alternate-day access to HFD (IMF-HFD), and switched to ad libitum low-fat diet (LFD; 10% fat) or received IMF of LFD (IMF-LFD). After 4 weeks, IMF-HFD (?13%) and IMF-LFD (?18%) had significantly lower body weights than the HFD. Body fat was also lower (?40%-52%) in all diet interventions. Lean mass was increased in the IMF-LFD (?12%-13%) compared with the HFD and IMF-HFD groups. Oral glucose tolerance area under the curve was lower in the IMF-HFD (?50%), whereas the insulin tolerance area under the curve was reduced in all diet interventions (?22%-42%). HPLC measurements of hypothalamic tissue homogenates indicated higher (?55%-60%) norepinephrine (NE) content in the anterior regions of the medial hypothalamus of IMF compared with the ad libitum-fed groups, whereas NE content was higher (?19%-32%) in posterior regions in the IMF-LFD group only. Relative gene expression of Npy in the arcuate nucleus was increased (?65%-75%) in IMF groups. Our novel findings indicate that intermittent fasting produces alterations in hypothalamic NE and neuropeptide Y, suggesting the counterregulatory processes of short-term weight loss are associated with an IMF dietary strategy.
Project description:<h4>Background</h4>Blueberry is rich in bioactive substances and possesses powerful antioxidant potential, which can protect against oxidant-induced and inflammatory cell damage and cytotoxicity. The aim of this study was to determine how blueberry affects glucose metabolism and pancreatic ?-cell proliferation in high fat diet (HFD)-induced obese mice.<h4>Methods</h4>Wild type male mice at age of 4?weeks received two different kinds of diets: high-fat diet (HFD) containing 60% fat or modified HFD supplemented with 4% (wt:wt) freeze-dried whole blueberry powder (HFD?+?B) for 14?weeks. A separate experiment was performed in mice fed with low-fat diet (LFD) containing 10% fat or modified LFD?+?B supplemented with 4% (wt:wt) freeze-dried whole blueberry powder. The metabolic parameters including blood glucose and insulin levels, glucose and insulin tolerances were measured.<h4>Results</h4>Blueberry-supplemented diet significantly increased insulin sensitivity and glucose tolerance in HFD?+?B mice compared to HFD mice. However, no difference was observed in blood glucose and insulin sensitivity between LFD?+?B and LFD mice. In addition, blueberry increased ?-cell survival and prevented HFD-induced ?-cell expansion. The most important finding was the observation of presence of small scattered islets in blueberry treated obese mice, which may reflect a potential role of blueberry in regenerating pancreatic ?-cells.<h4>Conclusions</h4>Blueberry-supplemented diet can prevent obesity-induced insulin resistance by improving insulin sensitivity and protecting pancreatic ?-cells. Blueberry supplementation has the potential to protect and improve health conditions for both type 1 and type 2 diabetes patients.
Project description:This study aims to investigate the effect of feeding low-fat diet (LFD) to diet-induced obesity (DIO) mice lacking TLR5 (TLR5(-/-)), which have a tendency to develop glucose intolerance with increased adiposity, compared to that in C57BL/6 mice.TLR5(-/-) and C57BL/6 male mice were divided into three subgroups: (1) control, mice were fed a standard AIN-76A (fat: 11.5 kcal%) diet for 12 weeks; (2) DIO, mice were fed a 58 kcal% high-fat diet (HFD) for 12 weeks; and (3) diet, mice were fed a HFD for 8 weeks to induce obesity and then switched to a 10.5 kcal% LFD for 4 weeks. The glucose intolerance in DIO TLR5(-/-) mice was more significant than that in DIO C57BL/6 mice and was not attenuated by a switch to the LFD. Weight-reduction with LFD had significantly decreased the epididymal fat mass in C57BL/6 mice but not in TLR5(-/-) mice. In addition, the LFD-fed TLR5(-/-) mice showed significantly higher expression of ghrelin in the serum and resistin in the epididymal fat than that in C57BL/6 mice.This study demonstrated that TLR5 gene knockout impairs some effects of weight-reduction in DIO.
Project description:<i>Background:</i> This study aimed at assessing the effect of a low-fat diet (LFD) in obese mice lacking toll?like receptors (Tlr) and understanding the expression and regulation of microRNAs during weight reduction. <i>Methods:</i> C57BL/6, Tlr5<sup>-/-</sup>, Tlr2<sup>-/-</sup> and Tlr4<sup>-/-</sup> mice were used in this study. A group of mice were fed with a high-fat diet (HFD) (58% kcal) for 12 weeks to induce obesity (diet-induced obesity, DIO). Another group that had been fed with HFD for eight weeks (obese mice) were switched to a low-fat diet (LFD) (10.5% kcal) for the next four weeks to reduce their body weight. The control mice were fed with a standard AIN-76A diet for the entire 12 weeks. The body weight of the mice was measured weekly. At the end of the experiment, epididymal fat weight and adipocyte size were measured. The differentially expressed miRNAs in the fat tissue was determined by next-generation sequencing with real-time quantitative reverse transcription polymerase chain reaction (RT?qPCR). Target prediction and functional annotation of miRNAs were performed using miRSystem database. <i>Results:</i> Switching to LFD significantly reduced the body weight and epididymal fat mass in the HFD-fed C57BL/6 and Tlr5<sup>-/-</sup> mice but not in Tlr2<sup>-/-</sup> and Tlr4<sup>-/-</sup> mice. Weight reduction significantly decreased the size of adipocytes in C57BL/6 but not in the <i>Tlr</i> knockout mice. In Tlr2<sup>-/-</sup> and Tlr4<sup>-/-</sup> mice, feeding with HFD and the subsequent weight reduction resulted in an aberrant miRNA expression in the epididymal fat tissue unlike in C57BL/6 and Tlr5<sup>-/-</sup>. However, target prediction and functional annotation by miRSystem database revealed that all the top 10 Kyoto Encyclopedia of Genes and Genomes (KEGG) database pathways of the dysregulated miRNAs during weight reduction in the C57BL/6 mice were also found in the regulated pathways of Tlr5<sup>-/-</sup>, Tlr2<sup>-/-</sup>, and Tlr4<sup>-/-</sup> strains. However, among these pathways, gene sets involved in arginine and proline metabolism and glutathione metabolism were mainly involved in the <i>Tlr</i> knockout mice but not in the C57BL/6 mice. <i>Conclusions:</i> In this study, we demonstrated that feeding of LFD leads to significant body weight reduction in C57BL/6 and Tlr5<sup>-/-</sup> mice, but not in Tlr2<sup>-/-</sup> and Tlr4<sup>-/-</sup> mice. Significant reduction in the size of adipocytes of epididymal fat was only found in C57BL/6, but not in Tlr5<sup>-/-</sup>, Tlr2<sup>-/-</sup>, and Tlr4<sup>-/-</sup> mice. The dysregulated miRNAs in Tlr2<sup>-/-</sup> and Tlr4<sup>-/-</sup> mice were different from those in C57BL/6 and Tlr5<sup>-/-</sup> strains. Among those miRNA-regulated pathways, arginine and proline metabolism as well as glutathione metabolism may have important roles in the <i>Tlr</i> knockout mice rather than in C57BL/6 mice.
Project description:<h4>Background</h4>Sepsis is a potentially deadly disease that often is caused by gram-positive bacteria, in particular Staphylococcus aureus (S. aureus). As there are few effective therapies for sepsis, increased basic knowledge about factors predisposing is needed.<h4>Methodology/principal findings</h4>The purpose of this study was to study the effect of Western diet on mortality induced by intravenous S. aureus inoculation and the immune functions before and after bacterial inoculation. Here we show that C57Bl/6 mice on high-fat diet (HFD) for 8 weeks, like genetically obese Ob/Ob mice on low-fat diet (LFD), have increased mortality during S. aureus-induced sepsis compared with LFD-fed C57Bl/6 controls. Bacterial load in the kidneys 5-7 days after inoculation was increased 10-fold in HFD-fed compared with LFD-fed mice. At that time, HFD-fed mice had increased serum levels and fat mRNA expression of the immune suppressing cytokines interleukin-1 receptor antagonist (IL-1Ra) and IL-10 compared with LFD-fed mice. In addition, HFD-fed mice had increased serum levels of the pro-inflammatory IL-1beta. Also, HFD-fed mice with and without infection had increased levels of macrophages in fat. The proportion and function of phagocytosing granulocytes, and the production of reactive oxygen species (ROS) by peritoneal lavage cells were decreased in HFD-fed compared with LFD-fed mice.<h4>Conclusions</h4>Our findings imply that chronic HFD disturb several innate immune functions in mice, and impairs the ability to clear S. aureus and survive sepsis.
Project description:Drug pharmacokinetics can be altered in obese and diabetic subjects. In consideration of the prevalence of obesity and diabetes, characterization of transporter expression in mouse models of diabetes and obesity may be a useful tool to aid in prediction of altered drug pharmacokinetics or adverse drug reactions. It has been reported that ob/ob mice, which display a severe obesity and diabetes phenotype, exhibit multiple changes in drug transporter expression in liver and kidney. In the present study, the mRNA and protein expression of major drug transporters was determined in livers and kidneys of diet-induced obese (DIO) C57BL/6J male mice. The mice were fed a high-fat diet (HFD) (60% fat) from 6 weeks of age and display obesity, fatty liver, and mild hyperglycemia. The HFD diet increased expression of multidrug resistance-associated proteins Abcc3 and 4 mRNA and protein in liver by 3.4- and 1.4-fold, respectively, compared with that detected in control mice fed a low-fat diet (LFD). In contrast, Abcc1 mRNA and protein decreased by 50% in livers of DIO mice compared with those in livers to lean mice. The HFD did not alter transporter expression in kidney compared with the LFD. In summary, unlike ob/ob and db/db mice, DIO mice exhibited a selective induction of efflux transporter expression in liver (i.e., Abcc3 and 4). In addition, diet-induced obesity affects transporter expression in liver but not kidney in the C57BL/6J mouse model. These data indicate that hepatic transporter expression is only slightly altered in a model of mild diabetes and nonalcoholic fatty liver disease and obesity.
Project description:Obesity is characterized by chronic inflammation and immune dysregulation, as well as insulin resistance, but the link between obesity and adaptive immunity remains to be fully studied.To elucidate the role of adaptive immunity on body composition, glucose homeostasis and inflammation, recombination-activating gene 1 knockout (Rag1-/-) mice, without mature T-lymphocytes or B-lymphocytes, were maintained on a low- or high-fat diet (LFD and HFD, respectively) for 11 weeks.Rag1-/- mice fed HFD gained significantly more weight and had increased body fat compared with wild type. Downregulation of energy expenditure as well as brown fat uncoupling protein UCP-1 and UCP-3 gene expression were noticed in HFD-fed Rag1-/- mice compared with LFD. HFD mice had significantly decreased energy intake compared with LFD mice, consistent with decreased agouti-related protein and increased pro-opiomelanocortin gene expression levels in the hypothalamus. Moreover, compared with wild type, Rag1-/- mice had lower interleukin (IL)-4 levels, a cytokine recently found to induce browning in white adipocytes, and higher IL-12 levels in HFD-fed Rag1-/- mice. Despite that HFD Rag1-/- mice were more obese, they had similar glucose, insulin and adiponectin levels, while leptin was marginally increased.Mice with deficiency in adaptive immunity are obese, partly owing to decreased energy expenditure, but are metabolically normal, suggesting that mature lymphocytes have necessary roles in the development of obesity-related metabolic dysregulation.
Project description:<h4>Objective</h4>Adrenomedullin (ADM) possesses therapeutic potential for inflammatory diseases. Consequently, the effects of ADM on inflammation in visceral white adipose tissue (vWAT) of obese rats or in adipocytes were explored in this study.<h4>Methods</h4>Male rats were fed a high-fat diet for 12 weeks to induce obesity, and obese rats were implanted with osmotic minipumps providing constant infusion of ADM (300 ng/kg per hour) and continued to be fed a high-fat diet for 4 weeks.<h4>Results</h4>When compared with the control group, endogenous protein expression of ADM and ADM receptors in vWAT and in lipopolysaccharide (LPS)-treated adipocytes was markedly increased. ADM significantly decreased the protein expression of the inflammatory mediators TNF?, IL-1?, cyclooxygenase-2, and inducible nitric oxide synthase in vWAT of obese rats and in adipocytes stimulated by LPS. It also inhibited the activation of the inflammatory signaling pathways MAPK and NF-?B induced by LPS in adipocytes. These effects of ADM in adipocytes were inhibited by the administration of ADM receptor antagonist and cAMP-dependent protein kinase (PKA) activation inhibitor.<h4>Conclusions</h4>ADM can inhibit inflammation in WAT in obesity, which may be mediated by the activation of ADM receptors and PKA.
Project description:Obesity is associated with an increased risk of colon cancer. Our current study examines whether weight loss and/or treatment with the non-steroidal anti-inflammatory drug (NSAID) sulindac suppresses the protumor effects of obesity in a mouse model of colon cancer. Azoxymethane-treated male FVB/N mice were fed a low-fat diet (LFD) or high-fat diet (HFD) for 15 weeks, then HFD mice were randomized to remain on HFD (obese) or switch to LFD (formerly obese (FOb-LFD)). Within the control (LFD), obese, and FOb-LFD groups, half the mice were also randomized to start sulindac treatment (140 ppm in the diet). All mice were euthanized seven weeks later. FOb-LFD mice had intermediate levels of body weight, lower than obese but higher than control mice (P<0.05). Sulindac did not affect body weight. Obese mice had greater tumor multiplicity and burden than all other groups (P<0.05). Transcriptomic profiling indicated that both weight loss and sulindac modulate the expression of tumor genes related to invasion and may promote a more anti-tumor immune landscape. Furthermore, the fecal microbes Prevotella and Akkermansia muciniphila, both known to be elevated in colorectal cancer patients, were positively correlated with tumor multiplicity and reduced by sulindac in obese mice. In sum, either moderate weight loss or sulindac treatment completely reversed the effects of chronic obesity on colon tumorigenesis. Our findings suggest that an investigation regarding the effects of NSAID treatment on colon cancer risk and/or progression in obese individuals is warranted, particularly for those unable to achieve moderate weight loss.
Project description:To examine the circulating microRNA (miRNA) expression profile in a mouse model of diet-induced obesity (DIO) with subsequent weight reduction achieved via low-fat diet (LFD) feeding.Eighteen C57BL/6NCrl male mice were divided into three subgroups: (1) control, mice were fed a standard AIN-76A (fat: 11.5 kcal %) diet for 12 weeks; (2) DIO, mice were fed a 58 kcal % high-fat diet (HFD) for 12 weeks; and (3) DIO?+?LFD, mice were fed a HFD for 8 weeks to induce obesity and then switched to a 10.5 kcal % LFD for 4 weeks. A switch to LFD feeding led to decreases in body weight, adiposity, and blood glucose levels in DIO mice. Microarray analysis of miRNA using The Mouse & Rat miRNA OneArray® v4 system revealed significant alterations in the expression of miRNAs in DIO and DIO?+?LFD mice. Notably, 23 circulating miRNAs (mmu-miR-16, mmu-let-7i, mmu-miR-26a, mmu-miR-17, mmu-miR-107, mmu-miR-195, mmu-miR-20a, mmu-miR-25, mmu-miR-15b, mmu-miR-15a, mmu-let-7b, mmu-let-7a, mmu-let-7c, mmu-miR-103, mmu-let-7f, mmu-miR-106a, mmu-miR-106b, mmu-miR-93, mmu-miR-23b, mmu-miR-21, mmu-miR-30b, mmu-miR-221, and mmu-miR-19b) were significantly downregulated in DIO mice but upregulated in DIO?+?LFD mice. Target prediction and function annotation of associated genes revealed that these genes were predominantly involved in metabolic, insulin signaling, and adipocytokine signaling pathways that directly link the pathophysiological changes associated with obesity and weight reduction.These results imply that obesity-related reductions in the expression of circulating miRNAs could be reversed through changes in metabolism associated with weight reduction achieved through LFD feeding.