Lysates of Methylococcus capsulatus Bath induce a lean-like microbiota, intestinal FoxP3+RORγt+IL-17+ Tregs and improve metabolism

Interactions between host and gut microbial communities are modulated by diets and play pivotal roles in immunological homeostasis and health. We show that exchanging the protein source in a high fat, high sugar, westernized diet from casein to whole-cell lysates of the non-commensal bacterium Methylococcus capsulatus Bath is sufficient to reverse western diet-induced changes in the gut microbiota to a state resembling that of lean, low fat diet-fed mice, both under mild thermal stress (T22 °C) and at thermoneutrality (T30 °C). Concomitant with microbiota changes, mice fed the Methylococcus-based western diet exhibit improved glucose regulation, reduced body and liver fat, and diminished hepatic immune infiltration. Intake of the Methylococcu-based diet markedly boosts Parabacteroides abundances in a manner depending on adaptive immunity, and upregulates triple positive (Foxp3+RORγt+IL-17+) regulatory T cells in the small and large intestine. Collectively, these data point to the potential for leveraging the use of McB lysates to improve immunometabolic homeostasis.publishedVersio

Associations between APOE Variants and Metabolic Traits and the Impact of Psychological Stress

In a previous study, we observed that associations between APOE rs439401 and metabolic traits were moderated by chronic stress. Thus, in a population of stressed and non-stressed Danish men, we examined whether associations between APOE rs439401 and a panel of metabolic quantitative traits, all metabolic traits which may lead to T2D and CVD were moderated by psychological stress.Obese young men (n = 475, BMI ≥ 31.0 kg/m(2)) and a randomly selected control group (n = 709) identified from a population of 141,800 men were re-examined in two surveys (S-46: mean age 46, S-49: mean age 49 years) where anthropometric and biochemical measures were available. Psychological stress factors were assessed by a self-administered 7-item questionnaire. Each item had the possible response categories "yes" and "no" and assessed familial problems and conflicts. Summing positive responses constituted a stress item score, which was then dichotomized into stressed and non-stressed. Logistic regression analysis, applying a recessive genetic model, was used to assess odds ratios (OR) of the associations between APOE rs439401 genotypes and adverse levels of metabolic traits.The APOE rs439401 TT-genotype associated positively with BMI (OR = 1.09 [1.01; 1.17]), waist circumference (OR = 1.09 [1.02; 1.17]) in stressed men at S-46. Positive associations were observed for fasting plasma glucose (OR = 1.42 [1.07; 1.87]), serum triglycerides (OR = 1.41 [1.05; 1.91]) and with fasting plasma insulin (OR = 1.48 [1.05; 2.08]) in stressed men at S-49. Rs439401 TT-genotype also associated positively with surrogate measures of insulin resistance (HOMA-IR; OR = 1.21 [1.03; 1.41]) and inversely with insulin sensitivity (Stumvoll index; OR = 0.90 [0.82; 0.99], BIGTT-S(I); OR = 0.60 [0.43; 0.85]) in stressed men. No significant associations were observed in non-stressed men, albeit the estimates showed similar but weaker trends as in stressed men.The present results suggest that the APOE rs439401 TT-genotype is associated with an adverse metabolic profile in a population of psychologically stressed Danish men

Sucrose Counteracts the Anti-Inflammatory Effect of Fish Oil in Adipose Tissue and Increases Obesity Development in Mice

BACKGROUND: Polyunsaturated n-3 fatty acids (n-3 PUFAs) are reported to protect against high fat diet-induced obesity and inflammation in adipose tissue. Here we aimed to investigate if the amount of sucrose in the background diet influences the ability of n-3 PUFAs to protect against diet-induced obesity, adipose tissue inflammation and glucose intolerance. METHODOLOGY/PRINCIPAL FINDINGS: We fed C57BL/6J mice a protein- (casein) or sucrose-based high fat diet supplemented with fish oil or corn oil for 9 weeks. Irrespective of the fatty acid source, mice fed diets rich in sucrose became obese whereas mice fed high protein diets remained lean. Inclusion of sucrose in the diet also counteracted the well-known anti-inflammatory effect of fish oil in adipose tissue, but did not impair the ability of fish oil to prevent accumulation of fat in the liver. Calculation of HOMA-IR indicated that mice fed high levels of proteins remained insulin sensitive, whereas insulin sensitivity was reduced in the obese mice fed sucrose irrespectively of the fat source. We show that a high fat diet decreased glucose tolerance in the mice independently of both obesity and dietary levels of n-3 PUFAs and sucrose. Of note, increasing the protein∶sucrose ratio in high fat diets decreased energy efficiency irrespective of fat source. This was accompanied by increased expression of Ppargc1a (peroxisome proliferator-activated receptor, gamma, coactivator 1 alpha) and increased gluconeogenesis in the fed state. CONCLUSIONS/SIGNIFICANCE: The background diet influence the ability of n-3 PUFAs to protect against development of obesity, glucose intolerance and adipose tissue inflammation. High levels of dietary sucrose counteract the anti-inflammatory effect of fish oil in adipose tissue and increases obesity development in mice

ThermoMouse: An In Vivo Model to Identify Modulators of UCP1 Expression in Brown Adipose Tissue

Summary: Obesity develops when energy intake chronically exceeds energy expenditure. Because brown adipose tissue (BAT) dissipates energy in the form of heat, increasing energy expenditure by augmenting BAT-mediated thermogenesis may represent an approach to counter obesity and its complications. The ability of BAT to dissipate energy is dependent on expression of mitochondrial uncoupling protein 1 (UCP1). To facilitate the identification of pharmacological modulators of BAT UCP1 levels, which may have potential as antiobesity medications, we developed a transgenic model in which luciferase activity faithfully mimics endogenous UCP1 expression and its response to physiologic stimuli. Phenotypic screening of a library using cells derived from this model yielded a small molecule that increases UCP1 expression in brown fat cells and mice. Upon adrenergic stimulation, compound-treated mice showed increased energy expenditure. These tools offer an opportunity to identify pharmacologic modulators of UCP1 expression and uncover regulatory pathways that impact BAT-mediated thermogenesis. : Pharmacological activation of brown adipose tissue (BAT) thermogenesis and energy dissipation, a process mediated by UCP1, may be useful to counter the energy imbalance that engenders obesity. Galmozzi et al. have developed an in vivo model to monitor UCP1 expression in real time and identified a small molecule that increases UCP1 levels. Mice treated with this molecule show greater energy expenditure upon adrenergic stimulation. Discovery of compounds with this ability is an important stride toward enhancing BAT function in obese individuals

p53 regulates expression of uncoupling protein 1 through binding and repression of PPARγ coactivator-1α

The tumor suppressor p53 (TRP53 in mice) is known for its involvement in carcinogenesis, but work during recent years has underscored the importance of p53 in the regulation of whole body metabolism. A general notion is that p53 is necessary for efficient oxidative metabolism. The importance of UCP1-dependent uncoupled respiration and increased oxidation of glucose and fatty acids in brown or brown-like, termed BRITE or beige, adipocytes in relation to energy balance and homeostasis has recently been highlighted. UCP1-dependent uncoupled respiration in classic interscapular brown adipose tissue is central to cold-induced thermogenesis, whereas BRITE/beige adipocytes are of special importance in relation to diet-induced thermogenesis, where the importance of UCP1 is only clearly manifested in mice kept at thermoneutrality. We challenged wildtype and TRP53-deficient mice by high fat feeding under thermoneutral conditions. Interestingly, mice lacking TRP53 gained less weight compared to their wildtype counterparts. This was related to an increased expression of Ucp1 and other PPARGC1a and PPARGC1b target genes, but not Ppargc1a or Ppargc1b in inguinal white adipose tissue of mice lacking TRP53. We show that TRP53, independently of its ability to bind DNA, inhibits the activity of PPARGC1a and PPARGC1b. Collectively, our data shows that TRP53 has the ability to regulate the thermogenic capacity of adipocytes through modulation of PPARGC1 activity

Discovery of a Novel Selective PPARγ Ligand with Partial Agonist Binding Properties by Integrated <i>in Silico</i>/<i>in Vitro</i> Work Flow

Full agonists to the peroxisome proliferator-activated receptor (PPAR)­γ, such as Rosiglitazone, have been associated with a series of undesired side effects, such as weight gain, fluid retention, cardiac hypertrophy, and hepatotoxicity. Nevertheless, PPARγ is involved in the expression of genes that control glucose and lipid metabolism and is an important target for drugs against type 2 diabetes, dyslipidemia, atherosclerosis, and cardiovascular disease. In an effort to identify novel PPARγ ligands with an improved pharmacological profile, emphasis has shifted to selective ligands with partial agonist binding properties. Toward this end we applied an integrated <i>in silico</i>/<i>in vitro</i> workflow, based on pharmacophore- and structure-based virtual screening of the ZINC library, coupled with competitive binding and transactivation assays, and adipocyte differentiation and gene expression studies. Hit compound <b>9</b> was identified as the most potent ligand (IC₅₀ = 0.3 μM) and a relatively poor inducer of adipocyte differentiation. The binding mode of compound <b>9</b> was confirmed by molecular dynamics simulation, and the calculated free energy of binding was −8.4 kcal/mol. A novel functional group, the carbonitrile group, was identified to be a key substituent in the ligand–protein interactions. Further studies on the transcriptional regulation properties of compound <b>9</b> revealed a gene regulatory profile that was to a large extent unique, however functionally closer to that of a partial agonist