Americans spend $8 billion a year fighting inflamed sinuses. Chronic rhinosinusitis also accounts for 20 percent of the antibiotic prescriptions issued to US adults, giving it an outsize role in the mounting problem of antibiotic resistance. So finding good alternative treatments could be a big deal.
Over the past several years, the Penn Rhinology Lab has been investigating a potential pathway via a surprising type of cell: taste receptors. Those, of course, cover our tongues. But they have recently been found elsewhere in the body, including airways and the gastrointestinal tract. A series of studies led by Noam Cohen, director of rhinology research at Penn, has established that taste receptors in the airways play a role in immune responses.
In 2012 his team found that one type of receptor, which on the tongue detects bitterness, in the airway releases antimicrobial peptides that kill bacteria, viruses, and fungi that enter the nose. Two years later, they found that this infection-fighting response by bitter-taste receptors was blocked when nearby sweet-taste receptors were stimulated with sugar. Their latest study, published in Science Signaling in September, indicates that sweet-taste receptors are also activated by certain amino acids produced by Staphylococcus bacteria.
“These amino acids,” said Cohen, “block the body’s natural immune response by essentially hitting the brakes on the defensive bitter-taste receptors.” In other words, in the chemical warfare of rhinosinusitis, bacteria are targeting sweet-taste receptors to do their bidding.
That suggests a possible treatment.
“Sweet-receptor blockers, which are known and used in some food and supplement products, may be useful to block activation” of those cells, said the study’s lead author, Robert Lee Gr’08, an assistant professor of otorhinolaryngology and physiology. “[That] would allow the body’s normal defenses to work properly,” even when bacteria are pumping out their amino-acid munitions.
The researchers are now investigating such a therapy.