Taste Receptors: Regulators of Sinonasal Innate Immunity

Taste receptors in the oral cavity guide our preferences for foods, preventing toxic ingestions and encouraging proper nutrient consumption. More recently, expression of taste receptors has been demonstrated in other locations throughout the body, including the airway, gastrointestinal tract, pancreas, and brain. The extent and specific roles of "extraoral" taste receptors are largely unknown, but a growing body of evidence suggests that taste receptors in the airway serve a critical role in sensing bacteria and regulating innate immunity. This review will focus on the function of bitter and sweet taste receptors in the human airway with particular emphasis on T2R38, a bitter taste receptor found in sinonasal ciliated cells, and bitter and sweet receptors found on specialized sinonasal solitary chemosensory cells. The importance of these novel taste receptor-immune circuits in the human airway and their clinical relevance in airway disease will also be reviewed.