title: Bitter and sweet taste receptors regulate human upper respiratory innate immunity.
abstract: Bitter taste receptors (T2Rs) in the human airway detect harmful compounds, including secreted bacterial products. Here, using human primary sinonasal air-liquid interface cultures and tissue explants, we determined that activation of a subset of airway T2Rs expressed in nasal solitary chemosensory cells activates a calcium wave that propagates through gap junctions to the surrounding respiratory epithelial cells. The T2R-dependent calcium wave stimulated robust secretion of antimicrobial peptides into the mucus that was capable of killing a variety of respiratory pathogens. Furthermore, sweet taste receptor (T1R2/3) activation suppressed T2R-mediated antimicrobial peptide secretion, suggesting that T1R2/3-mediated inhibition of T2Rs prevents full antimicrobial peptide release during times of relative health. In contrast, during acute bacterial infection, T1R2/3 is likely deactivated in response to bacterial consumption of airway surface liquid glucose, alleviating T2R inhibition and resulting in antimicrobial peptide secretion. We found that patients with chronic rhinosinusitis have elevated glucose concentrations in their nasal secretions, and other reports have shown that patients with hyperglycemia likewise have elevated nasal glucose levels. These data suggest that increased glucose in respiratory secretions in pathologic states, such as chronic rhinosinusitis or hyperglycemia, promotes tonic activation of T1R2/3 and suppresses T2R-mediated innate defense. Furthermore, targeting T1R2/3-dependent suppression of T2Rs may have therapeutic potential for upper respiratory tract infections.
authors: Robert J
authors: RJ
authors: Lee
authors: Jennifer M
authors: JM
authors: Kofonow
authors: Philip L
authors: PL
authors: Rosen
authors: Adam P
authors: AP
authors: Siebert
authors: Bei
authors: B
authors: Chen
authors: Laurel
authors: L
authors: Doghramji
authors: Guoxiang
authors: G
authors: Xiong
authors: Nithin D
authors: ND
authors: Adappa
authors: James N
authors: JN
authors: Palmer
authors: David W
authors: DW
authors: Kennedy
authors: James L
authors: JL
authors: Kreindler
authors: Robert F
authors: RF
authors: Margolskee
authors: Noam A
authors: NA
authors: Cohen
mesh_terms: D020013:Calcium Signaling; D002478:Cells, Cultured; D002923:Cilia / Q000502:physiology; D004847:Epithelial Cells / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D006801:Humans; D007113:Immunity, Innate; D009297:Nasal Mucosa / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D011550:Pseudomonas aeruginosa / Q000276:immunology; D000644:Quaternary Ammonium Compounds / Q000494:pharmacology; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000378:metabolism*; D012220:Rhinitis / Q000276:immunology / Q000378:metabolism; D012852:Sinusitis / Q000276:immunology / Q000378:metabolism; D046509:Tissue Culture Techniques; D000098706:Taste Receptors, Type 2
chemical_list: D000644:Quaternary Ammonium Compounds; D043562:Receptors, G-Protein-Coupled; C431926:taste receptors, type 1; D000098706:Taste Receptors, Type 2; C043414:denatonium; D005947:Glucose