Int J Oral Biol.  2012 Jun;37(2):57-62.

Expression of Bitter Taste Receptors in Human Nasal Respiratory Epithelium

• An JM
• Wu HW
• Kim HJ
• Kim CH
• Moon SJ

Abstract

The nasal cavity encounters various irritants during inhalation such as dust and pathogens. To detect and remove these irritants, it has been postulated that the nasal mucosa epithelium has a specialized sensing system. The oral cavity, on the other hand, is known to have bitter taste receptors (T2Rs) that can detect harmful substances to prevent ingestion. Recently, solitary chemosensory cells expressing T2R subtypes have been found in the respiratory epithelium of rodents. In addition, T2Rs have been identified in the human airway epithelia. However, it is not clear which T2Rs are expressed in the human nasal mucosa epithelium and whether they mediate the removal of foreign materials through increased cilia movement. In our current study, we show that human T2R receptors indeed function also in the nasal mucosa epithelium. Our RT-PCR data indicate that the T2R subtypes (T2R3, T2R4, T2R5, T2R10, T2R13, T2R14, T2R39, T2R43, T2R44, T2R 45, T2R46, T2R47, T2R48, T2R49, and T2R50) are expressed in human nasal mucosa. Furthermore, we have found that T2R receptor activators such as bitter chemicals augments the ciliary beating frequency. Our results thus demonstrate that T2Rs are likely to function in the cleanup of inhaled dust and pathogens by increasing ciliary movement. This would suggest that T2Rs are feasible molecular targets for the development of novel treatment strategies for nasal infection and inflammation.

Keyword

bitter taste receptor (T2R); nasal epithelium; ciliary beating frequency (CBF)

MeSH Terms

Cilia
Dust
Eating
Epithelium
Hand
Humans
Inflammation
Inhalation
Irritants
Mouth
Nasal Cavity
Nasal Mucosa
Receptors, G-Protein-Coupled
Respiratory Mucosa
Rodentia
Dust
Irritants
Receptors, G-Protein-Coupled