Project description:Microbial functions in the host physiology are a result of co-evolution between microbial communities and their hosts. Here we show that cold exposure leads to marked shift of the microbiota composition, referred to as cold microbiota. Transplantation of the cold microbiota to germ-free mice is sufficient to increase the insulin sensitivity of the host, and enable complete tolerance to cold partly by promoting the white fat browning, leading to increased energy expenditure and fat loss. During prolonged cold however, the body weight loss is attenuated, caused by adaptive mechanisms maximising caloric uptake and increasing intestinal, villi and microvilli lengths. This increased absorptive surface is promoted by the cold microbiota - effect that can be diminished by co-transplanting the most downregulated bacterial strain from the Verrucomicrobia phylum, Akkermansia muciniphila, during the cold microbiota transfer. Our results demonstrate the microbiota as a key factor orchestrating the overall energy homeostasis during increased demand.
Project description:Tributyltin (TBT), an environmental pollutant widely used in antifouling coatings, can cause multiple-organ toxicity and gut microbiome dysbiosis in organisms, and can even cause changes in the host metabolomic profiles. However, little is known about the underlying effects and links of TBT-induced metabolic changes and gut microbiome dysbiosis. In this study, rats were exposed to TBT at a dose of 100 μg kg-1 body weight (BW) for 38 days, followed by multi-omics analysis, including microbiome, metabolomics, and metallomics. Results showed that TBT exposure reduced rat weight gain and decreased the serum triglyceride (TG) level. Metabolic analysis revealed that TBT fluctuated linoleic acid metabolism and glycerophospholipid metabolism in the liver; the tricarboxylic acid cycle (TCA cycle), nicotinate and nicotinamide metabolism, and arachidonic acid metabolism in serum; glycine, serine, and threonine metabolism, the one carbon pool by folate, nicotinate, and nicotinamide metabolism; and tryptophan metabolism in feces. Furthermore, TBT treatment dictated liver inflammation due to enhancing COX-2 expression by activating protein kinase R-like ER kinase (PERK) and C/EBP homologous protein (CHOP) to induce endoplasmic reticulum (ER) stress instead of stimulating arachidonic acid metabolism. Meanwhile, alteration of the intestinal flora [Acetivibrio]_ethanolgignens_group, Acetatifactor, Eisenbergiella, Lachnospiraceae_UCG-010, Enterococcus, Anaerovorax, and Bilophila under TBT exposure were found to be involved in further mediating liver inflammation, causing lipid metabolism abnormalities, such as TG, linoleic acid, and glycerophospholipids, and interfering with the energy supply process. Among these, [Acetivibrio]_ethanolgignens_group, Enterococcus, and Bilophila could be considered as potential biomarkers for TBT exposure based on receiver operator characteristic (ROC) curve analysis.
Project description:Microbial functions in the host physiology are a result of co-evolution between microbial communities and their hosts. Here we show that cold exposure leads to marked shift of the microbiota composition, referred to as cold microbiota. Transplantation of the cold microbiota to germ-free mice is sufficient to increase the insulin sensitivity of the host, and enable complete tolerance to cold partly by promoting the white fat browning, leading to increased energy expenditure and fat loss. During prolonged cold however, the body weight loss is attenuated, caused by adaptive mechanisms maximising caloric uptake and increasing intestinal, villi and microvilli lengths. This increased absorptive surface is promoted by the cold microbiota - effect that can be diminished by co-transplanting the most downregulated bacterial strain from the Verrucomicrobia phylum, Akkermansia muciniphila, during the cold microbiota transfer. Our results demonstrate the microbiota as a key factor orchestrating the overall energy homeostasis during increased demand.
Project description:Animal nutrition is profoundly influenced by the gut microbiota, but knowledge of the scope and core mechanisms of the underlying animal-microbiota interactions is fragmentary. To investigate the nutritional traits shaped by the gut microbiota of Drosophila, we determined the microbiota-dependent response of multiple metabolic and performance indices to systematically varied diet composition. Diet-dependent differences between Drosophila bearing its unmanipulated microbiota (conventional flies) and experimentally deprived of its microbiota (axenic flies) revealed evidence for: microbial sparing of dietary B vitamins, especially riboflavin, on low-yeast diets; microbial promotion of protein nutrition, particularly in females; and microbiota-mediated suppression of lipid/carbohydrate storage, especially on high sugar diets. The microbiota also sets the relationship between energy storage and body mass, indicative of microbial modulation of the host signaling networks that coordinate metabolism with body size. This analysis identifies the multiple impacts of the microbiota on the metabolism of Drosophila, and demonstrates that the significance of these different interactions varies with diet composition and host sex.
Project description:Gut microbiota plays an important role in metabolic homeostasis. Previous studies demonstrated that ginsenoside Rb1 might improve obesity-induced metabolic disorders through regulating glucose and lipid metabolism in the liver and adipose tissues. Due to low bioavailability and enrichment in the intestinal tract of Rb1, we hypothesized that modulation of the gut microbiota might account for its pharmacological effects as well. Here, we show that oral administration of Rb1 significantly decreased serum LDL-c, TG, insulin, and insulin resistance index (HOMA-IR) in mice with a high-fat diet (HFD). Dynamic profiling of the gut microbiota showed that this metabolic improvement was accompanied by restoring of relative abundance of some key bacterial genera. In addition, the free fatty acids profiles in feces were significantly different between the HFD-fed mice with or without Rb1. The content of eight long-chain fatty acids (LCFAs) was significantly increased in mice with Rb1, which was positively correlated with the increase of Akkermansia and Parasuttereller, and negatively correlated with the decrease of Oscillibacter and Intestinimonas. Among these eight increased LCFAs, eicosapentaenoic acid (EPA), octadecenoic acids, and myristic acid were positively correlated with metabolic improvement. Furthermore, the colonic expression of the free fatty acid receptors 4 (Ffar4) gene was significantly upregulated after Rb1 treatment, in response to a notable increase of LCFA in feces. These findings suggested that Rb1 likely modulated the gut microbiota and intestinal free fatty acids profiles, which should be beneficial for the improvement of metabolic disorders in HFD-fed mice. This study provides a novel mechanism of Rb1 for the treatment of metabolic disorders induced by obesity, which may provide a therapeutic avenue for the development of new nutraceutical-based remedies for treating metabolic diseases, such as hyperlipidemia, insulin resistance, and type 2 diabetes.
Project description:The microorganisms within the intestinal tract (termed gut microbiota) have been shown to interact with the gut-brain axis, a bidirectional communication system between the gut and the brain mediated by hormonal, immune, and neural signals. Through these interactions, the microbiota might affect behaviors, including feeding behavior, digestive/absorptive processes (e.g., by modulating intestinal motility and the intestinal barrier), metabolism, as well as the immune response, with repercussions on the energy homeostasis and health of the host. To date, research in this field has mostly focused on mammals. Studies on non-mammalian models such as fish may provide novel insights into the specific mechanisms involved in the microbiota-brain-gut axis. This review describes our current knowledge on the possible effects of microbiota on feeding, digestive processes, growth, and energy homeostasis in fish, with emphasis on the influence of brain and gut hormones, environmental factors, and inter-specific differences.
Project description:Purpose: NGS was used to determine if a distinct transcriptomic profile is observed among the experimental mice fed four different dietary components. Methods: We carried out RNA-Seq analysis of ileum tissue from 6 weeks male mice ad libitum fed for 10 weeks a high liquid sugar (23% (w/v)) or/and high fat (60% Kcal from fat) diet. The combined effect of sugar drink and high fat diet (HF-Sugar) was compared with sugar drink only (NF-Sugar), or high fat diet only (HF), or control diet that was plain water and normal fat diet (NF). Results: RNA-Seq revealed sample-specific clusters that included genes responding to each experimental diet. We found only addition of sugar drink to high fat group (HF-Sugar) not NF-Sugar and HF, there was a significant enrichment in biological functions relating to Inflammatory/Immune Responses, especially including dendritic cell (DC) and T cell related signaling pathway. Conclusions: Taken together, our data demonstrate that sugar drink synergistically promotes and exacerbates inflammatory responses driven by the high fat diet.
Project description:The mammalian gastrointestinal tract contains a diverse ecosystem of microbial species collectively making up the gut microbiome. Emerging evidence highlights a critical relationship between gut microbiota and neurocognitive development. Consumption of unhealthy yet palatable dietary factors associated with obesity and metabolic dysfunction (e.g., saturated fat, added sugar) produces microbiota dysbiosis and negatively impacts neurocognitive function, particularly when consumed during early life developmental periods. Here we explore whether excessive early life consumption of added sugars negatively impacts neurocognitive development via the gut microbiome. Using a rodent model of habitual sugar-sweetened beverage (SSB) consumption during the adolescent stage of development, we first show that excessive early life sugar intake impairs hippocampal-dependent memory function when tested during adulthood while preserving other neurocognitive domains. Gut microbiome genomic sequencing analyses reveal that early life SSB consumption alters the abundance of various bacterial populations, including elevations in operational taxonomic units within the genus Parabacteroides (P. distasonis and P. johnsonii) whose abundance negatively correlated with memory task performance. Additional results reveal that in vivo Parabacteroides enrichment of cultured P. distasonis and P. johnsonii bacterial species in adolescent rats severely impairs memory function during adulthood. Hippocampus transcriptome analyses identify gene expression alterations in neurotransmitter synaptic signaling, intracellular kinase signaling, metabolic function, neurodegenerative disease, and dopaminergic synaptic signaling-associated pathways as potential mechanisms linking microbiome outcomes with memory impairment. Collectively these results identify microbiota dysbiosis as a mechanism through which early life unhealthy dietary patterns negatively impact neurocognitive outcomes.
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.