title: Monitoring host responses to the gut microbiota.
abstract: The gastrointestinal (GI) ecosystem is increasingly understood to be a fundamental component of health, and has been identified as a new focal point for diagnosing, correcting and preventing countless disorders. Shotgun DNA sequencing has emerged as the dominant technology for determining the genetic and microbial composition of the gut microbiota. This technology has linked microbiota dysbioses to numerous GI diseases including inflammatory bowel disease, obesity and allergy, and to non-GI diseases like autism and depression. The importance of establishing causality in the deterioration of the host-microbiota relationship is well appreciated; however, discovery of candidate molecules and pathways that underlie mechanisms remains a major challenge. Targeted approaches, transcriptional assays, cytokine panels and imaging analyses, applied to animals, have yielded important insight into host responses to the microbiota. However, non-invasive, hypothesis-independent means of measuring host responses in humans are necessary to keep pace with similarly unbiased sequencing efforts that monitor microbes. Mass spectrometry-based proteomics has served this purpose in many other fields, but stool proteins exist in such diversity and dynamic range as to overwhelm conventional proteomics technologies. Focused analysis of host protein secretion into the gut lumen and monitoring proteome-level dynamics in stool provides a tractable route toward non-invasively evaluating dietary, microbial, surgical or pharmacological intervention efficacies. This review is intended to guide GI biologists and clinicians through the methods currently used to elucidate host responses in the gut, with a specific focus on mass spectrometry-based shotgun proteomics applied to the study of host protein dynamics within the GI ecosystem.
authors.affiliation: Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA.
authors.forename: Joshua S
authors.identifier: 0000000252566773
authors.initials: JS
authors.lastname: Lichtman
authors.affiliation: Department of Microbiology and Immunology, Stanford University, Stanford, CA, USA.
authors.forename: Justin L
authors.initials: JL
authors.lastname: Sonnenburg
authors.affiliation: Department of Chemical and Systems Biology, Stanford University, Stanford, CA, USA.
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Elias
mesh_terms: D000818:Animals; D004032:Diet; D005243:Feces / Q000737:chemistry; D000069196:Gastrointestinal Microbiome; D054884:Host-Pathogen Interactions; D006801:Humans; D007249:Inflammation; D013058:Mass Spectrometry; D064307:Microbiota / Q000502:physiology*; D020543:Proteome / Q000502:physiology*; D040901:Proteomics; D017422:Sequence Analysis, DNA
chemical_list: D020543:Proteome