The Role of Taste Receptors in Airway Innate Immune Defense

Bitter (T2R) and sweet (T1R) taste receptors are expressed in the upper airway, where they play key roles in antimicrobial innate immune defense. Bitter bacterial products are detected by taste receptors on ciliated cells and solitary chemosensory cells, resulting in downstream nitric oxide and antimicrobial peptide release, respectively. Genetic polymorphisms in taste receptors contribute to variations in T1R and T2R functionality, and phenotypic differences correlate with disease status and disease severity in chronic rhinosinusitis (CRS). Correspondingly, there are also subjective bitter and sweet taste differences between patients with CRS and individuals without CRS across a number of compounds. The ability to capture these differences with a simple and inexpensive taste test provides a potentially useful diagnostic tool, while bitter compounds themselves could potentially serve as therapeutic agents. The present review examines the physiology of airway taste receptors and the recent literature elucidating the role taste receptors play in rhinologic disease.