Project description:The human gut is colonized by trillions of microorganisms that influence human health and disease through the metabolism of xenobiotics, including therapeutic drugs and antibiotics. The diversity and metabolic potential of the human gut microbiome have been extensively characterized, but it remains unclear which microorganisms are active and which perturbations can influence this activity. Here, we use flow cytometry, 16S rRNA gene sequencing, and metatranscriptomics to demonstrate that the human gut contains distinctive subsets of active and damaged microorganisms, primarily composed of Firmicutes, which display marked temporal variation. Short-term exposure to a panel of xenobiotics resulted in significant changes in the physiology and gene expression of this active microbiome. Xenobiotic-responsive genes were found across multiple bacterial phyla, encoding novel candidate proteins for antibiotic resistance, drug metabolism, and stress response. These results demonstrate the power of moving beyond DNA-based measurements of microbial communities to better understand their physiology and metabolism. RNA-Seq analysis of the human gut microbiome during exposure to antibiotics and therapeutic drugs.
Project description:Gut bacterial β-glucuronidases (GUS) promote the toxic side effects of therapeutics by reactivating drugs from their inactive glucuronide conjugates. It is increasingly clear that the interindividual variability of bacterial GUS-producing species in the gut microbiota contributes to differential drug responses. Indeed, the anticancer drug irinotecan exhibits variable clinical toxicity outcomes that have been linked to interindividual differences in the composition of the gut microbiota. However, identification of the specific GUS enzymes responsible for drug metabolism in the context of the complexity of the human fecal microbiota has not been achieved. Here we pinpoint the specific bacterial GUS enzymes that reactivate SN-38, the active metabolite of irinotecan, from complex human fecal microbiota samples with activity-based protein profiling (ABPP). We identify and quantify gut bacterial GUS enzymes from human feces with ABPP-enabled proteomics and then integrate this information with ex vivo kinetics to reveal the specific GUS enzymes responsible for the reactivation of SN-38. The same ABPP approach also reveals the molecular basis for differential gut bacterial GUS inhibition between human fecal samples. Taken together, this work provides an unprecedented pipeline to identify the specific bacterial GUS enzymes responsible for drug-induced GI toxicity from the complexity of human feces, which may serve as highly precise biomarkers of clinical outcomes for irinotecan and other therapeutics.
Project description:The gut microbiota-intestine-liver relationship is emerging as an important factor in multiple hepatic pathologies, but the hepatic sensors and effectors of microbial signals are not well defined. By comparing publicly available liver transcriptomics data from conventional vs. germ-free mice, we identified pregnane X receptor (PXR, NR1I2) transcriptional activity as strongly affected by the absence of gut microbes. Microbiota depletion in Pxr+/+ vs Pxr-/- C57Bl6/J mice revealed that most microbiota-sensitive genes were PXR-dependent in the liver in males, but not in females. Pathway enrichment analysis revealed that microbiota-PXR interaction controlled fatty-acid and xenobiotic metabolism. Antibiotic treatment reduced liver triglyceride content and hampered xenobiotic metabolism in livers from Pxr+/+ but not Pxr-/- male mice. These findings identify PXR as a hepatic effector of sexually dimorphic responses to microbiota-derived signals and reveal a potential new mechanism for unexpected drug-drug or food-drug interactions.
Project description:Eriocitrin, found in lemon fruit, has shown a wide range of biological properties. Herein, to evaluate the intestinal metabolic profile of eriocitrin in colon, the flavonoids in mice colon contents were identified by ultra performance liquid chromatography-electrospray ionization-tandem mass spectrometry (UPLC-ESI-MS/MS), and a total of 136 flavonoids were found, including eriocitrin and its six metabolites (eriodictyol, homoeriodictyol, hesperetin, eriodictyol-3'-O-glucoside, hesperetin-7-O-glucoside and eriodictyol-7-O-(6''-O-galloyl) glucoside). Mice colon contents were used for 16S rDNA gene sequencing and gas chromatography-mass (GC-MS). Resultu showed that eriocitrin significantly alters the beta diversity of the gut microbiota, the probiotics such as Lachnospiraceae_UCG_006 were significantly enriched, and the production of butyrate, valerate and hexanoate in the colon pool of short-chain fatty acids (SCFAs) were significant increased. The spearman's association analysis performed some intestinal bacteria may be involved in the metabolism of eriocitrin. Collectively, our results preliminarily suggesting the metabolism of eriocitrin in the gut, demonstrate alterations of eriocitrin on gut microbiota, which warrants further investigation to determine its potential use in food and biomedical applications.
Project description:The human gut is colonized by trillions of microorganisms that influence human health and disease through the metabolism of xenobiotics, including therapeutic drugs and antibiotics. The diversity and metabolic potential of the human gut microbiome have been extensively characterized, but it remains unclear which microorganisms are active and which perturbations can influence this activity. Here, we use flow cytometry, 16S rRNA gene sequencing, and metatranscriptomics to demonstrate that the human gut contains distinctive subsets of active and damaged microorganisms, primarily composed of Firmicutes, which display marked temporal variation. Short-term exposure to a panel of xenobiotics resulted in significant changes in the physiology and gene expression of this active microbiome. Xenobiotic-responsive genes were found across multiple bacterial phyla, encoding novel candidate proteins for antibiotic resistance, drug metabolism, and stress response. These results demonstrate the power of moving beyond DNA-based measurements of microbial communities to better understand their physiology and metabolism.
Project description:The trillions of microorganisms in the human gastrointestinal tract are an underexplored aspect of pharmacology. Despite numerous examples of microbial effects on drug efficacy and toxicity, there is often an incomplete understanding of the underlying mechanisms. Here, we dissect the inactivation of the commonly prescribed cardiac glycoside, digoxin, by Eggerthella lenta. Whole genome transcriptional profiling, comparative genomics, and culture-based assays revealed a cytochrome-encoding operon up-regulated by digoxin, absent in non-metabolizing E. lenta strains, and predictive of the efficiency of digoxin inactivation by the human gut microbiome. Digoxin inactivation was further enhanced by microbial interactions and inhibited by arginine. Pharmacokinetic studies using gnotobiotic mice revealed that increasing dietary protein reduces the in vivo metabolism of digoxin by E. lenta, with significant changes to drug concentration in the urine and serum. These results emphasize the importance of viewing pharmacology from the perspective of both our human and microbial genomes. RNA-Seq analysis of Eggerthella lenta cultured with or without digoxin.
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:We generate B-cell-specific Tlr9-deficient (Tlr9fl/fl/Cd19Cre+/-, KO) B6 mice and model obesity using a high-fat diet. Compared with control mice, B cell Tlr9-deficient mice exhibited increased weight gain, impaired glucose and insulin tolerance, reduced IL-10-producing B cells and increased inflammation in fat tissues. Tlr9 deficiency affected B cell differentiation, immunoglobulin levels, and T cell subsets. Furthermore, altered gut microbiota in B-cell-specific Tlr9-deficient mice led to a pro-inflammatory status in gut associated lymphoid tissues and glucose metabolism dysregulation. Using 16S rRNA sequencing we report altered gut microbial communities in the KO mice. Indeed, a reduction in Lachnospiraceae, may play a key role in the observed metabolic phenotypes in KO mice. Also, We identify an important network involving Tlr9, Irf4 and Il-10.
Project description:In vitro gut microbiota models are often used to study drug-microbiome interaction. Similar to culturing individual microbial strains, the biomass accumulation of in vitro gut microbiota follows a logistic growth curve. Current studies on in vitro gut microbiome responses introduce drug stimulation during different growth stages, e.g. lag phase or stationary phase. However, in vitro gut microbiota in different growth phases may respond differently to a same stimuli. Therefore, in this study, we used a 96-deep well plate-based culturing model (MiPro) to culture the human gut microbiota. Metformin, as the stimulus, was added at the lag, log and stationary phases of growth. Microbiome samples were collected at different time points for optical density and metaproteomic functional analysis. Results show that in vitro gut microbiota responded differently to metformin added during different growth phases, in terms of the growth curve, alterations of taxonomic and functional compositions. The addition of drugs at log phase leads to the greatest decline of bacterial growth. Metaproteomic analysis suggested that the strength of the metformin effect on the gut microbiome functional profile was ranked as lag phase > log phase > stationary phase. Our results showed that metformin added at lag phase resulted in a significantly reduced abundance of the Clostridiales order as well as an increased abundance of the Bacteroides genus, which was different from stimulation during the rest of the growth phase. Metformin also resulted in alterations of several pathways, including energy production and conversion, lipid transport and metabolism, translation, ribosomal structure and biogenesis. Our results indicate that the timing for drug stimulation should be considered when studying drug-microbiome interactions in vitro.