title: Molecular analysis of model gut microbiotas by imaging mass spectrometry and nanodesorption electrospray ionization reveals dietary metabolite transformations.
abstract: The communities constituting our microbiotas are emerging as mediators of the health-disease continuum. However, deciphering the functional impact of microbial communities on host pathophysiology represents a formidable challenge, due to the heterogeneous distribution of chemical and microbial species within the gastrointestinal (GI) tract. Herein, we apply imaging mass spectrometry (IMS) to localize metabolites from the interaction between the host and colonizing microbiota. This approach complements other molecular imaging methodologies in that analytes need not be known a priori, offering the possibility of untargeted analysis. Localized molecules within the GI tract were then identified in situ by surface sampling with nanodesorption electrospray ionization Fourier transform ion cyclotron resonance-mass spectrometry (nanoDESI FTICR-MS). Products from diverse structural classes were identified including cholesterol-derived lipids, glycans, and polar metabolites. Specific chemical transformations performed by the microbiota were validated with bacteria in culture. This study illustrates how untargeted spatial characterization of metabolites can be applied to the molecular dissection of complex biology in situ.
authors.affiliation: Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, San Diego, California 92093, United States.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Rath
authors.forename: Theodore
authors.initials: T
authors.lastname: Alexandrov
authors.forename: Steven K
authors.initials: SK
authors.lastname: Higginbottom
authors.forename: Jiao
authors.initials: J
authors.lastname: Song
authors.forename: Marcos E
authors.initials: ME
authors.lastname: Milla
authors.forename: Michael A
authors.initials: MA
authors.lastname: Fischbach
authors.forename: Justin L
authors.initials: JL
authors.lastname: Sonnenburg
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Dorrestein
mesh_terms: D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001419:Bacteria / Q000254:growth & development / Q000378:metabolism; D001647:Bile Acids and Salts / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D001711:Biotransformation; D046508:Culture Techniques; D004032:Diet; D007422:Intestines / Q000382:microbiology*; D013058:Mass Spectrometry; D055432:Metabolomics; D051379:Mice; D064307:Microbiota; D057054:Molecular Imaging / Q000379:methods*; D036103:Nanotechnology / Q000379:methods*; D011134:Polysaccharides / Q000378:metabolism
chemical_list: D001647:Bile Acids and Salts; D015415:Biomarkers; D011134:Polysaccharides; D016718:Arachidonic Acid