Gastrointestinal Bitter Taste Receptors Exhibit Inter-Regional and Inter-Individual Variation

The gastrointestinal (GI) tract may function as a sensory organ responding to changes in luminal content. Its ability to regulate physiological functions is, in part, determined by the bitter chemosensory capacity of the gut mucosa. We mapped the regional variation of GI tract bitter taste receptors (TAS2Rs) in order to better understand their relationship to GI function and the gut-brain axis. Mucosal biopsies from the stomach (fundus, body and antrum), duodenum (D2), proximal jejunum, terminal ileum, colon (ascending, transverse, and sigmoid), and rectum were collected from volunteers with no previous gut disorders who were undergoing routine screening by gastroscopy or colonoscopy. Nanostringtm analysis of TAS2R transcription was conducted on 300 biopsies taken from 28 volunteers. TAS2Rs showed a diverse transcription profile throughout the human GI tract. Two archetypes of gut chemosensing existed with several individuals displaying a more complete TAS2R profile in all regions of the gut. Additionally, regional variation was observed in several TAS2Rs that correlated with cytogenetic location. These data show significant inter-individual and regional variation in gut bitter chemosensory systems reflecting differing luminal sensing capacity in different gut regions and between people.