Project description:The High Fat Diet (HFD)-feeding significantly stimulated fat accumulation in Drosophila adults. Simultaneous feeding of known anti-obesity drugs that having the effect on rat and mouse, Quercetin Glycosides (QG) and Epigallocatechin gallate (EGCG) also suppressed fat accumulation in Drosophila at an equivalent concentration. Therefore, we have established a convenient model system to study on diet-induced fat accumulation and to evaluate effects of anti-obesity drugs using Drosophila. To understand overview of alterations of gene expression due to diet-induced fat accumulation and its suppression by the known anti-obesity drugs, we performed the RNA seq analyses. Consequently, mRNA levels of several genes involved in lipid metabolism, glycolysis/gluconeogenesis and anti-oxidative stress have changed in adults fed the HFD. Moreover, the levels altered in those fed on HFD supplemented with QG or EGCG. Our qRT-PCR further confirmed the RNA-seq data suggesting that expression of five genes essential for lipid metabolism was changed in HFD-fed animals and further altered in the animals treated with anti-obesity drugs. Among them, the most remarkable alteration was observed in dHSL gene encoding a lipase involved in lipid-storage after HFD feeding and the HFD supplemented with QG or EGCG. These changes are consistent with HFD-induced fat accumulation as well as the anti-obesity effects of those two drugs in mammals, suggesting that these genes play an important role in the anti-obesity effects of the drugs. These are the first evidences that whole profiles of altered gene expression under a condition of a diet-induced obesity and its suppression by anti-obesity drugs in Drosophila.
Project description:A high-sugar diet induces lifestyle-associated metabolic diseases, such as obesity and diabetes, which may underlie the pro-tumor effects of a high-sugar diet. We supplied GL261 syngeneic glioblastoma (GBM) model mice with a short-term high-glucose diet (HGD) and found an increased survival rate with no evidence of metabolic disease. Modulation of the gut microbiota by an HGD was critical for enhancing the anti-tumor immune response. Single-cell RNA sequencing showed that modulation of the gut microbiota by an HGD increased the T cell-mediated anti-tumor immune response in GBM mice. We found that the cytotoxic CD4+ T cell population in GBM mice increased due to synergy with anti-PD-1 immune checkpoint inhibitors, but this depended on an HGD. Thus, we determined that an HGD enhanced anti-tumor immune responses in GBM mice through changes in the gut microbiota and suggest that the role of an HGD in GBM should be re-examined.
Project description:Previous studies have implicated a causal role for the gut bacterium Akkermansia muciniphila in counteracting diet-induced obesity and metabolic dysfunctions. However, a systems level understanding of the molecular mechanisms underlying the anti-obesogenic effect of A. muciniphila is lacking. Using fructose-induced obese mice as a model, we carried out multiomics studies to investigate the molecular cascades mediating the effect of A. muciniphila. We found that A. muciniphila colonization in fructose-induced obese mice triggered significant shifts in gut microbiota composition as well as alterations in numerous gut and plasma metabolites and gene expression in the hypothalamus. Among these, we found that the metabolite oleoyl-ethanolamide in the gut and circulation and hypothalamic oxytocin are the key regulators of gut-brain interactions that underlie the A. muciniphila anti-obesity effect. Our multiomics investigation elucidates the molecular regulators and pathways involved in the communication between A. muciniphila in the gut and hypothalamic neurons that counter fructose-induced obesity .
Project description:Germfree (GF) mice have been used as a model to study the contribution of the intestinal microbiota to metabolic energy balance of the host. Despite a wealth of knowledge accumulated since the 1940’s, the response of GF mice to a high fat diet is largely unknown. In the present study, we compared the metabolic consequences of a high fat (HF) diet on GF and conventional (Conv) C57BL/6J mice. As expected, Conv mice developed obesity and glucose intolerance with a HF diet. In contrast, GF mice remained lean and resisted the HF diet-induced insulin resistance. The anti-obesity phenotype of GF/HF mice was accompanied by reduced caloric intake, diminished food efficiency, and excessive fecal lipid excretion contributed to the reduced food efficiency. In addition, HF diet-induced hypercholesterolemia was ameliorated, which was partially due to an increase in fecal cholesterol excretion. However, hepatic cholesterols were increased in GF/HF mice. Elevated nuclear SREBP2 proteins and the up-regulation of cholesterol biosynthesis genes support the increased liver cholesterol biosynthesis in GF/HF mice. The resistance to HF diet-induced metabolic abnormalities in GF mice was also associated with a reduced immune response, indicated by low plasma pro-inflammatory and anti-inflammatory markers. These data suggest that the gut microbiota of Conv mice contributes to HF diet-induced obesity, insulin resistance, dyslipidemia and hepatic steatosis in mice. Thus, results of the present study describe the metabolic responses of GF mice to a HF diet and further our understandings of the relationship between the gut microbiota and the host. Germfree and conventional C57BL/6J mice were fed with a high fat diet for 11 weeks. Then, all mice were sacrified under 10-h food deprevation, and liver samples of germfree (n=14) and conventional (n=16) were examined.
Project description:Gut microbiota has profound effects on obesity and associated metabolic disorders. Targeting and shaping the gut microbiota via dietary intervention using probiotics, prebiotics and synbiotics can be effective in obesity management. Despite the well-known association between gut microbiota and obesity, the microbial alternations by synbiotics intervention, especially at the functional level, are still not characterized. In this study, we investigated the effects of synbiotics on high fat diet (HFD)-induced metabolic disorders, and systematically profiled the microbial profile at both the phylogenetic and functional levels. Synbiotics significantly reversed the HFD-induced change of microbial populations at the levels of richness, taxa and OTUs. Potentially important species Faecalibaculum rodentium and Alistipes putredinis that might mediate the beneficial effects of synbiotics were identified. At the functional level, short chain fatty acid and bile acid profiles revealed that interventions significantly restored cecal levels of acetate, propionate, and butyrate, and synbiotics reduced the elevated total bile acid level. Metaproteomics revealed the effect of synbiotics might be mediated through pathways involved in carbohydrate, amino acid, and energy metabolisms, replication and repair, etc. These results suggested that dietary intervention using our novel synbiotics alleviated HFD-induced weight gain and restored microbial ecosystem homeostasis phylogenetically and functionally.
Project description:The aim of this study was to investigate the causative effect of CS induced dysbiosis on obesity and insulin resistance in a high-fat diet induced obese (DIO) mouse model. Male germ-free BALB/c mice were humanized by fecal microbiota transfer using samples from children born by CS or VD and fed HFD for 16 weeks. Adipose tissue was sampled for RNAseq at study termination.
Project description:We studied the effect of dietary fat type, varying in polyunsaturated/saturated fatty acid ratio's (P/S) on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1) or safflower oil (HF-SO; P/S 7.8) for 8 weeks. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared to the HF-OO, HF-SO or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes/Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis. Keywords: Diet intervention study Nine-week-old C57Bl/6J mice were fed a low-fat diet (LF-PO) and three different types of high-fat diet, based on palm oil (HF-PO; P/S1.0), olive oil (HF-OO; P/S4.6) and safflower oil (HF-SO; P/S10.1) for 8 weeks. Body weight was recorded weekly and after 7 weeks of diet intervention an oral glucose tolerance test was performed. After 2 weeks of diet intervention, 6 mice per high-fat diet group were anaesthetized with a mixture of isofluorane (1.5%), nitrous oxide (70%) and oxygen (30%) and the small intestines were excised. Adhering fat and pancreatic tissue were carefully removed. The small intestines were divided in three equal parts along the proximal to distal axis (SI 1, SI 2 and SI 3) and microarray analysis was performed on mucosal scrapings.
Project description:Germfree (GF) mice have been used as a model to study the contribution of the intestinal microbiota to metabolic energy balance of the host. Despite a wealth of knowledge accumulated since the 1940’s, the response of GF mice to a high fat diet is largely unknown. In the present study, we compared the metabolic consequences of a high fat (HF) diet on GF and conventional (Conv) C57BL/6J mice. As expected, Conv mice developed obesity and glucose intolerance with a HF diet. In contrast, GF mice remained lean and resisted the HF diet-induced insulin resistance. The anti-obesity phenotype of GF/HF mice was accompanied by reduced caloric intake, diminished food efficiency, and excessive fecal lipid excretion contributed to the reduced food efficiency. In addition, HF diet-induced hypercholesterolemia was ameliorated, which was partially due to an increase in fecal cholesterol excretion. However, hepatic cholesterols were increased in GF/HF mice. Elevated nuclear SREBP2 proteins and the up-regulation of cholesterol biosynthesis genes support the increased liver cholesterol biosynthesis in GF/HF mice. The resistance to HF diet-induced metabolic abnormalities in GF mice was also associated with a reduced immune response, indicated by low plasma pro-inflammatory and anti-inflammatory markers. These data suggest that the gut microbiota of Conv mice contributes to HF diet-induced obesity, insulin resistance, dyslipidemia and hepatic steatosis in mice. Thus, results of the present study describe the metabolic responses of GF mice to a HF diet and further our understandings of the relationship between the gut microbiota and the host.