Project description:Gut microbiota plays an important role during early development via bidirectional gut- brain signaling. We aimed to explore the potential link between gut microbiota/gut derived metabolites and sympathoadrenal stress responsivity
Project description:Background: More than 100 million Americans are living with metabolic syndrome, increasing their propensity to develop heart disease– the leading cause of death worldwide. A major contributing factor to this epidemic is caloric excess, often a result of consuming low cost, high calorie fast food. Several recent seminal studies have demonstrated the pivotal role of gut microbes contributing to cardiovascular disease in a diet-dependent manner. Given the central contributions of diet and gut microbiota to cardiometabolic disease, we hypothesized that novel microbial metabolites originating postprandially after fast food consumption may contribute to cardiometabolic disease progression. Methods: To test this hypothesis, we gave conventionally raised or antibiotic-treated mice a single oral gavage of a fast food slurry or a control rodent chow diet slurry and sacrificed the mice four hours later. Here, we coupled untargeted metabolomics in portal and peripheral blood, 16S rRNA gene sequencing, targeted liver metabolomics, and host liver RNA sequencing to identify novel fast food-derived microbial metabolites. Results: We successfully identified several metabolites that were enriched in portal blood, increased by fast food feeding, and essentially absent in antibiotic-treated mice. Strikingly, just four hours post-gavage, we found that fast food consumption resulted in rapid reorganization of the gut microbial community structure and drastically altered hepatic gene expression. Importantly, diet-driven reshaping of the microbiome and liver transcriptome was dependent on a non-antibiotic ablated gut microbial community. Conclusions: Collectively, these data suggest that single fast food meal is sufficient to reshape the gut microbial community yielding a unique signature of food-derived microbial metabolites. Future studies are warranted to determine if these metabolites are causally linked to cardiometabolic disease.
Project description:The intestinal epithelium senses and responds to the myriad of signals from gut microbiota, but it remains unclear how these signals are integrated to drive physiological responses. In this work, we found that enterochromaffin (EC) cells in the gut serve as signal integration hubs for microbial metabolites. EC cells coordinate responses to combinations of microbial metabolites, resulting in complex alterations in serotonin signaling that drive changes in GI physiology. We found that microbial metabolites either directly trigger responses or alter the expression of receptors for other microbial metabolites in EC cells. The microbiota-derived purine derivative hypoxanthine triggers a signaling pathway by activating G-protein coupled receptor A1R, which in turn activates the calcium channel TRPC4, resulting in increased serotonin release and accelerated GI transit. On the other hand, bacteria-derived butyrate does not evoke EC cell calcium influx by itself, but drives epigenetic changes that upregulate TRPC4 expression, thereby enhancing response to metabolites like hypoxanthine and norepinephrine that act via TRPC4. Since the expression TRPC4 is limited to EC cells, these cells function as specialized epithelial sensors that integrate signals from regulatory (butyrate) and effector metabolites like hypoxanthine and norepinephrine. These findings offer new microbiota-driven therapeutic avenues for conditions associated with altered GI function.
Project description:Gut microbiota and their metabolites influence host gene expression and physiological status through diverse mechanisms. Here we investigate how gut microbiota and their metabolites impact host's mRNA m6A epitranscriptome in various antibiotic-induced microbiota dysbiosis models. With multi-omics analysis, we find that the imbalance of gut microbiota can rewire host mRNA m6A epitranscriptomic profiles in brain, liver and intestine. We further explore the underlying mechanisms regulating host mRNA m6A methylome by depleting the microbiota with ampicillin. Metabolomic profiling shows that cholic acids are the main down-regulated metabolites with Firmicutes as the most significantly reduced genus in ampicillin-treated mice comparing to untreated mice. Fecal microbiota transplantations in germ-free mice and metabolites supplementations in cells verify that cholic acids are associated with host mRNA m6A epitranscriptomic rewiring. Collectively, this study employs an integrative multi-omics analysis to demonstrate the impact of gut microbiota dysbiosis on host mRNA m6A epitranscriptomic landscape via cholic acid metabolism.
Project description:Gut microbiota and their metabolites influence host gene expression and physiological status through diverse mechanisms. Here we investigate how gut microbiota and their metabolites impact host′s mRNA m6A epitranscriptome in various antibiotic-induced microbiota dysbiosis models. With multi-omics analysis, we find that the imbalance of gut microbiota can rewire host mRNA m6A epitranscriptomic profiles in brain, liver and intestine. We further explore the underlying mechanisms regulating host mRNA m6A methylome by depleting the microbiota with ampicillin. Metabolomic profiling shows that cholic acids are the main down-regulated metabolites with Firmicutes as the most significantly reduced genus in ampicillin-treated mice comparing to untreated mice. Fecal microbiota transplantations in germ-free mice and metabolites supplementations in cells verify that cholic acids are associated with host mRNA m6A epitranscriptomic rewiring. Collectively, this study employs an integrative multi-omics analysis to demonstrate the impact of gut microbiota dysbiosis on host mRNA m6A epitranscriptomic landscape via cholic acid metabolism.
Project description:The enteric nervous system (ENS) senses microbiota-derived signals and orchestrates mucosal immunity and epithelial barrier functions, in health and disease. However, mechanistic dissections of intestinal neuro-immune-microbiota communications remain challenging and existing research methods limit experimental controllability and throughput. Here, we present a novel optogenetics-integrated gut organ culture system that enables real-time, whole-tissue stimulation of specific ENS lineages, allowing for detailed analysis of their functional impact. We demonstrate that optogenetic activation of enteric cholinergic neurons rapidly modulates intestinal physiology. Interestingly, distinct neuronal firing patterns differentially modulate neuro-immunological gene expression and epithelial barrier integrity. Furthermore, diverse enteric neuronal lineages exert distinct regulatory roles. While cholinergic activation promotes gene-sets associated with type-2 immunity, tachykininergic enteric neurons differentially control mucosal defense programs. Remarkably, luminal introduction of the immunomodulatory bacterium T. ramosa significantly remodeled cholinergic-induced neuro-immunological transcription. These findings suggest that complex combinatorial signals delivered by gut microbes and enteric neurons are locally integrated to fine-tune intestinal immunity and barrier defense. Collectively, we provide a powerful platform for systematic discovery and mechanistic exploration of functional neuroimmune connections, and their potential modulation by microbes, drugs or metabolites.
Project description:The enteric nervous system (ENS) senses microbiota-derived signals and orchestrates mucosal immunity and epithelial barrier functions, in health and disease. However, mechanistic dissections of intestinal neuro-immune-microbiota communications remain challenging and existing research methods limit experimental controllability and throughput. Here, we present a novel optogenetics-integrated gut organ culture system that enables real-time, whole-tissue stimulation of specific ENS lineages, allowing for detailed analysis of their functional impact. We demonstrate that optogenetic activation of enteric cholinergic neurons rapidly modulates intestinal physiology. Interestingly, distinct neuronal firing patterns differentially modulate neuro-immunological gene expression and epithelial barrier integrity. Furthermore, diverse enteric neuronal lineages exert distinct regulatory roles. While cholinergic activation promotes gene-sets associated with type-2 immunity, tachykininergic enteric neurons differentially control mucosal defense programs. Remarkably, luminal introduction of the immunomodulatory bacterium T. ramosa significantly remodeled cholinergic-induced neuro-immunological transcription. These findings suggest that complex combinatorial signals delivered by gut microbes and enteric neurons are locally integrated to fine-tune intestinal immunity and barrier defense. Collectively, we provide a powerful platform for systematic discovery and mechanistic exploration of functional neuroimmune connections, and their potential modulation by microbes, drugs or metabolites.
Project description:The effect of oral microbiota on the intestinal microbiota has garnered growing attention as a mechanism linking periodontal diseases to systemic diseases. However, the salivary microbiota is diverse and comprises numerous bacteria with a largely similar composition in healthy individuals and periodontitis patients. Thus, the systemic effects of small differences in the oral microbiota are unclear. In this study, we explored how health-associated and periodontitis-associated salivary microbiota differently colonized the intestine and their subsequent systemic effects by analyzing the hepatic gene expression and serum metabolomic profiles. The salivary microbiota was collected from a healthy individual and a periodontitis patient and gavaged into C57BL/6NJcl[GF] mice. Samples were collected five weeks after administration. Gut microbial communities were analyzed by 16S ribosomal RNA gene sequencing. Hepatic gene expression profiles were analyzed using a DNA microarray and quantitative polymerase chain reaction. Serum metabolites were analyzed by capillary electrophoresis time-of-flight mass spectrometry. The gut microbial composition at the genus level was significantly different between periodontitis-associated microbiota-administered (PAO) and health-associated oral microbiota-administered (HAO) mice. The hepatic gene expression profile demonstrated a distinct pattern between the two groups, with higher expression of Neat1, Mt1, Mt2, and Spindlin1, which are involved in lipid and glucose metabolism. Disease-associated metabolites such as 2-hydroxyisobutyric acid and hydroxybenzoic acid were elevated in PAO mice. These metabolites were significantly correlated with Bifidobacterium, Atomobium, Campylobacter, and Haemophilus, which are characteristic taxa in PAO mice. Conversely, health-associated oral microbiota were associated with higher levels of beneficial serum metabolites in HAO mice. The multi-omics approach used in this study revealed that periodontitis-associated oral microbiota is associated with the induction of disease phenotype when they colonized the gut of germ-free mice.
Project description:The gut microbiota is a key environmental determinant of mammalian metabolism. Regulation of white adipose tissue (WAT) by the gut microbiota is a critical process that maintains metabolic fitness, while dysbiosis contributes to the development of obesity and insulin resistance (IR). However, how the gut microbiota controls WAT functions remain largely unknown. Herein, we show that tryptophan-derived metabolites produced by the microbiota control the expression of the miR-181 family in white adipocytes to regulate energy expenditure and insulin sensitivity. Moreover, we show that dysregulation of the microbiota-miR-181 axis is required for the development of obesity, IR, and WAT inflammation. Thus, our results indicate that regulation of miRNA levels in WAT by microbiota-derived cues is a central mechanism by which host metabolism is tuned in response to dietary and environmental changes. As MIR-181 is dysregulated in WAT from obese human individuals, the MIR-181 family may represent a potential therapeutic target to modulate WAT function in the context of obesity.