MS/MS Mass Spectrometry Filtering Tree for Bile Acid Isomer Annotation

Area of Science:

• Biochemistry
• Analytical Chemistry
• Metabolomics

Background:

• Bile acids are crucial steroids with diverse physiological roles, including regulating immunity and metabolism.
• The structural complexity of bile acids leads to spectral similarities, challenging their identification using standard mass spectrometry techniques.
• Distinguishing between bile acid isomers is critical for understanding their specific functions.

Purpose of the Study:

• To develop and validate a novel workflow for differentiating isomeric bile acids in complex biological samples.
• To apply this workflow to untargeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) data.
• To identify specific bile acid metabolites associated with dietary factors.

Main Methods:

• Implementation of a mass spectrometry query language filtering tree for enhanced data analysis.
• Utilizing untargeted LC-MS/MS for comprehensive metabolite profiling.
• Development of a proof-of-concept workflow for isomer resolution.

Main Results:

• The developed workflow successfully distinguished between various bile acid isomers.
• A novel bile acid conjugate, deoxycholyl-2-aminophenol amidate, was identified.
• This finding suggests a potential link between whole grain consumption and specific bile acid modifications.

Conclusions:

• The novel mass spectrometry-based workflow offers a powerful tool for resolving isomeric bile acids.
• The identification of deoxycholyl-2-aminophenol amidate provides new insights into bile acid metabolism and diet interactions.
• Further research can leverage this method to explore the broader roles of bile acid isomers in health and disease.