Project description:Increasing the consumption of dietary fibre has been proposed to alleviate the progression of non-communicable diseases such as obesity, type 2 diabetes and cardiovascular disease, yet the effect of dietary fibre on host physiology remains unclear. In this study, we performed a multiple diet feeding study in C57BL/6J mice to compare high fat and high fat modified with dietary fibre diets on host physiology and gut homeostasis by combining proteomic, metagenomic, metabolomic and glycomic techniques with correlation network analysis. We observed significant changes in physiology, liver proteome, gut microbiota and SCFA production in response to high fat diet. Dietary fibre modification did not reverse these changes but was associated with specific changes in the gut microbiota, liver proteome, SCFA production and colonic mucin glycosylation. Furthermore, correlation network analysis identified gut bacterial-glycan associations.
Project description:The human gut microbiota is crucial for degrading dietary fibres from the diet. However, some of these bacteria can also degrade host glycans, such as mucins, the main component of the protective gut mucus layer. Specific microbiota species and mucin degradation patterns are associated with inflammatory processes in the colon. Yet, it remains unclear how the utilization of mucin glycans affects the degradation of dietary fibres by the human microbiota. Here, we used three dietary fibres (apple pectin, β-glucan and xylan) to study in vitro the dynamics of colon mucin and dietary fibre degradation by the human faecal microbiota. The dietary fibres showed clearly distinguishing modulatory effects on faecal microbiota composition. The utilization of colon mucin in cultures led to alterations in microbiota composition and metabolites. Metaproteome analysis showed the central role of the Bacteroides in degradation of complex fibres while Akkermansia muciniphila was the main degrader of colonic mucin. This work demonstrates the intricacy of complex glycan metabolism by the gut microbiota and how the utilization of host glycans leads to alterations in the metabolism of dietary fibres. Metaproteomics analysis of this data reveals the functional activities of the bacteria in consortia, by this contributing to a better understanding of the complex metabolic pathways within the human microbiota that can be manipulated to maximise beneficial microbiota-host interactions.
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:The human gut microbiota is crucial for degrading dietary fibres from the diet. However, some of these bacteria can also degrade host glycans, such as mucins, the main component of the protective gut mucus layer. Specific microbiota species and mucin degradation patterns are associated with inflammatory processes in the colon. Yet, it remains unclear how the utilization of mucin glycans affects the degradation of dietary fibres by the human microbiota. Here, we used three dietary fibres (apple pectin, β-glucan and xylan) to study in vitro the dynamics of colon mucin and dietary fibre degradation by the human faecal microbiota. The dietary fibres showed clearly distinguishing modulatory effects on faecal microbiota composition. The utilization of colon mucin in cultures led to alterations in microbiota composition and metabolites. Metaproteome analysis showed the central role of the Bacteroides in degradation of complex fibres while Akkermansia muciniphila was the main degrader of colonic mucin. This work demonstrates the intricacy of complex glycan metabolism by the gut microbiota and how the utilization of host glycans leads to alterations in the metabolism of dietary fibres. Metaproteomics analysis of this data reveals the functional activities of the bacteria in consortia, by this contributing to a better understanding of the complex metabolic pathways within the human microbiota that can be manipulated to maximise beneficial microbiota-host interactions. In this study two different mucin samples were used: commercial porcine gastric mucin and in house prepared porcine colonic mucin. This dataset analyses the proteome of: A) autoclaved porcine colonic mucin; B) not autoclaved porcine colonic mucin; C) porcine gastric mucin.
Project description:Analysis of variation in subcutaneous adipose tissue gene expression in response to dietary intake of n-3 polyunsaturated fatty acids, as assessed in a cohot of individuals with metabolic syndrome. Outcomes from this study provide insight on molecular details of dietary effects on gene expression and metabolic health. Subcutaneous adipose tissue samples were taken from a cohort of seventeen individuals with metabolic syndrome. Habitual intake of n-3 polyunsaturated fatty acids was assessed with 3-day weighed food journals.
Project description:Purpose: Helminth infection and dietary intake can affect the intestinal microbiota, as well as the immune system. Methods: Here we analyzed the relationship between fecal microbiota and blood profiles of indigenous Malaysians, referred to locally as Orang Asli, in comparison to urban participants from the capital city of Malaysia, Kuala Lumpur. Results: We found that helminth infections had a larger effect on gut microbial composition than did dietary intake or blood profiles. Trichuris trichiura infection intensity also had the strongest association with blood transcriptional profiles. By characterizing paired longitudinal samples collected before and after deworming treatment, we determined that changes in serum zinc and iron levels among the Orang Asli were driven by changes in helminth infection status, independent of dietary metal intake. Serum zinc and iron levels were associated with changes in the abundance of several microbial taxa. Conclusions: There is considerable interplay between helminths, micronutrients and the microbiota on the regulation of immune responses in humans.
Project description:Dietary lipids can affect metabolic health through gut microbiota-mediated mechanisms, but the influence of lipid-microbiota interaction on liver steatosis is unknown. We investigated the effect of dietary lipid composition on human microbiota in an observational study and combined diet experiments with microbiota transplants to study lipid-microbiota interactions and liver status in mice. In humans, low intake of saturated fatty acids (SFA) was associated with increased microbial diversity independent of fiber intake. In mice, cecum levels of SFA correlated negatively with microbial diversity and were associated with a shift in butyrate and propionate producers. Mice fed poorly absorbed SFA had improved metabolism and liver status. These features were transmitted by microbial transfer. Diets enriched in n-6- and/or n-3-polyunsaturated fatty acids were protective against steatosis but had minor influence on the microbiota. In summary, we find that unabsorbed SFA correlate with microbiota features that may be targeted to decrease liver steatosis.
Project description:Dietary lipids and gut microbiota may both influence adipose tissue physiology. By feeding conventional and germ-free mice high fat diets with different lipid compositon we aimed to investigate how dietary lipids and the gut microbiota interact to influence inflammation and metabolism in the liver
Project description:Dietary lipids and gut microbiota may both influence adipose tissue physiology. By feeding conventional and germ-free mice high fat diets with different lipid compositon we aimed to investigate how dietary lipids and the gut microbiota interact to influence inflammation and metabolism in epididymal adipiose tissue (EWAT)
Project description:Dietary fats have been shown to affect gut microbiota composition and aging gene transcription of middle-aged rats at a normal dose, but little is known about such an effect on gut barrier. In colon, the main component of mucus layer is Muc2, produced by the goblet cells. This study investigated the changes in Muc2 expression, goblet cells proliferation, TLRs and inflammatory cytokines in the colon of middle-aged rats. Proteome technology was applied to explore the possible molecular mechanisms. The results indicated that intake of fish oil at a normal dose downregulated colonic Muc2 expression, and this negative effect of fish oil probably involved the suppression of mucin glycosylation process.