Using Multidimensional Separations to Distinguish Isomeric Amino Acid-Bile Acid Conjugates and Assess Their Presence...

Area of Science:

• Metabolomics
• Microbiome Research
• Analytical Chemistry

Background:

• Bile acids are crucial for nutrient absorption, inflammation, signaling, and gut microbiome composition.
• Traditional bile acid analysis often overlooks numerous microbial conjugated bile acids (MCBAs) produced by the gut microbiota.
• MCBAs are emerging as vital biomarkers for early disease detection and assessing gut health status.

Purpose of the Study:

• To synthesize and characterize a comprehensive library of 176 novel microbial conjugated bile acids (MCBAs).
• To develop an extended bile acid library including 182 unique compounds and ~250 rare bile acid extracts.
• To apply this library to analyze MCBA profiles in mice and humans undergoing perturbations like antibiotic treatment and fecal microbiota transplantation (FMT).

Main Methods:

• Synthesis of 176 MCBAs by conjugating 8 core bile acids with 22 amino acids.
• Utilized liquid chromatography-ion mobility spectrometry-mass spectrometry (LC-IMS-MS) for separation of isomeric conjugates.
• Creation of an in-house extended bile acid library and assessment of rare bile acid extracts.

Main Results:

• Successfully generated a library of 182 unique bile acid compounds, including novel MCBAs.
• Demonstrated the utility of the library in identifying and quantifying MCBAs in complex biological samples.
• Observed changes in MCBA profiles in mice treated with antibiotics and humans undergoing FMT.

Conclusions:

• The developed extended bile acid library significantly enhances the capacity for comprehensive bile acid profiling.
• This resource facilitates deeper understanding of the role of MCBAs in gut health and disease.
• The findings provide a foundation for using MCBAs as diagnostic biomarkers in clinical settings.