Project description:Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes. Here, we show that Bacteroides fragilis strain P207, isolated from a bacterial bloom in the J-pouch of a patient with ulcerative colitis pouchitis, conjugates standard amino acids and the neuroactive amines γ-aminobutyric acid (GABA) and tyramine to deoxycholic acid. We extended this analysis to other human gut isolates and identified species that are competent to conjugate GABA and tyramine to primary and secondary BAs, and further identified diverse BA-GABA and BA-tyramine amides in human stool. A longitudinal metabolomic analysis of J-pouch contents of the patient from whom B. fragilis P207 was isolated revealed highly reduced levels of secondary bile acids and a shifting BA amide profile before, during, and after onset of pouchitis, including temporal changes in several BA-GABA amides. Treatment of pouchitis with ciprofloxacin was associated with a marked reduction of nearly all BA amides in the J-pouch. Our study expands the known repertoire of conjugated bile acids produced by bacteria to include BA conjugates to GABA and tyramine and demonstrates that these molecules are present in the human gut. IMPORTANCE BAs are modified in multiple ways by host enzymes and the microbiota to produce a chemically diverse set of molecules that assist in the digestive process and impact many physiological functions. This study reports the discovery of bacterial species that conjugate the neuroactive amines, GABA and tyramine, to primary and secondary BAs. We further present evidence that BA-GABA and BA-tyramine conjugates are present in the human gut, and document a shifting BA-GABA profile in a human pouchitis patient before, during, and after inflammation and antibiotic treatment. GABA and tyramine are common metabolic products of the gut microbiota and potent neuroactive molecules. GABA- and tyramine-conjugated BAs may influence receptor-mediated regulatory mechanisms of humans and their gut microbes, and absorption of these molecules and their entry into enterohepatic circulation may impact host physiology at distal tissue sites. This study defines new conjugated bile acids in the human gut.
Project description:Bile acids (BAs) are cholesterol-derived molecules that aid in digestion and nutrient absorption, regulate host metabolic processes, and influence physiology of the gut microbiota. Both the host and its microbiome contribute to enzymatic modifications that shape the chemical diversity of BAs in the gut. Several bacterial species have been reported to conjugate standard amino acids to BAs, but it was not known if bacteria conjugate BAs to other amine classes. Here, we show that Bacteroides fragilis strain P207, isolated from a bacterial bloom in the J-pouch of a patient with ulcerative colitis (UC) pouchitis, conjugates standard amino acids and the neuroactive amines γ-aminobutyric acid (GABA) and tyramine to deoxycholic acid. We extended this analysis to other human gut isolates and identified species that are competent to conjugate GABA and tyramine to primary and secondary BAs, and further identified diverse BA-GABA and BA-tyramine amides in human stool. A longitudinal metabolomic analysis of J-pouch contents of the patient from whom B. fragilis P207 was isolated revealed highly reduced levels of secondary bile acids and a shifting BA amide profile before, during, and after onset of pouchitis, including temporal changes in several BA-GABA amides. Treatment of pouchitis with ciprofloxacin was associated with a marked reduction of nearly all BA amides in the J-pouch. Our study expands the known repertoire of conjugated bile acids produced by bacteria to include BA conjugates to GABA and tyramine and demonstrates that these molecules are present in the human gut.
Project description:Untargeted UPLC-MS/MS data from a screen of human gut microbiome commensal isolate bacteria from healthy human donor feces. Isolates include Mediterraneibacter gnavus MSK15.77 (NCBI accession NZ_JAAIRR010000000), Bacteroides ovatus MSK22.29 (NCBI accession NZ_JAHOCX010000000), Bifidobacterium longum DFI.2.45 (NCBI accession NZ_JAJCNS010000000), and Lachnoclostridium scindens SL.1.22 (NCBI accession GCA_020555615.1). The dataset includes validated bile acid standards. All using positive ionization.
Project description:UPLC-MS/MS data used to confirm the retention times of bile acid conjugates to GABA and tyramine that were detected in microbial culture and human fecal samples. Synthesized conjugates included here are GABA-deoxycholic acid, tyramine-deoxycholic acid, GABA-cholic acid, tyramine-cholic acid, GABA-chenodeoxycholic acid, and tyramine-chenodeoxycholic acid. Data of biological samples (B. fragilis P207 spiked with DCA, healthy human donor 11 feces, patient 207 v12 feces) from the same UPLCMS/MS sequence is included for comparison and validation. All using positive ionization.
Project description:Untargeted UPLC-MS/MS data from the initial screen comparing B. fragilis P207 (NCBI accession NZ_CP114371) cultures with and without deoxycholic acid spike revealed gamma-aminobutyrodeoxycholic acid and tyraminodeoxycholic acid among other bile acid conjugates in spiked cultures. All using positive ionization.
Project description:UPLC-MS/MS data from bile acid specificity screen comparing the ability of B. fragilis P207 (NCBI accession NZ_CP114371) to conjugate amines to deoxycholic acid, glycodeoxycholic acid, and cholic acid. All using positive ionization.
Project description:UPLC-MS/MS data used to confirm the retention times of bile acid conjugates to GABA and tyramine that were detected in microbial culture and human fecal samples. Synthesized conjugates included here are GABA-deoxycholic acid, tyramine-deoxycholic acid, GABA-cholic acid, tyramine-cholic acid, GABA-chenodeoxycholic acid, and tyramine-chenodeoxycholic acid. Data of biological samples (B. fragilis P207 spiked with DCA, healthy human donor 11 feces, patient 207 v12 feces) from the same UPLCMS/MS sequence is included for comparison and validation. All using positive ionization.
Project description:Bile acid amine conjugate identification by feeding of deoxycholic acid and isotope-labeled amine precursors to B. fragilis P207 (NCBI accession NZ_CP114371) followed by UHPLC-MS/MS analysis.
Project description:Exposure to high-dose radiation causes life-threatening serious intestinal damage. Histological analysis is the most accurate method for judging the extent of intestinal damage after death. However, it is difficult to predict the extent of intestinal damage to body samples. Here we focused on extracellular microRNAs (miRNAs) released from cells and investigated miRNA species that increased or decreased in serum and feces using a radiation-induced intestinal injury mouse model. A peak of small RNA of 25–200 nucleotides was detected in mouse serum and feces 72 h after radiation exposure, and miRNA presence in serum and feces was inferred. MiRNAs expressed in the small intestine and were increased by more than 2.0-fold in serum or feces following a 10 Gy radiation exposure were detected by microarray analysis and were 4 in serum and 19 in feces. In this study, miR-375-3p, detected in serum and feces, was identified as the strongest candidate for a high-dose radiation biomarker in serum and/or feces using a radiation-induced intestinal injury model.