Periodontitis is a serious gum disorder induced by an imbalance in the bacteria and other microorganisms of the mouth (the oral microbiome). It is the sixth-most prevalent infectious disease and the most common cause of tooth loss worldwide.

Monell Center Director and President Robert Margolskee, MD, PhD and cell biologist Marco Tizzano, PhD, along with colleagues from Sichuan University, found that the newly identified cells, known as solitary chemosensory cells (SCCs), are present in the gums of mice. Here they express several types of taste receptors along with a downstream coupling protein called gustducin. SCCs are taste-like chemical detectors that sense irritants and bacteria, and biologists have found them throughout the gut, urinary tract, nasal cavities, and now in the gums.

"These sensory cells may provide a new approach for personalized treatment of periodontitis by harnessing a person's own innate immune system to regulate their oral microbiome," said Margolskee.

The team showed that knocking out taste-signaling molecules like gustducin or genetically removing gum SCCs in the mice leads to overgrowth of pathogenic oral bacteria and periodontitis. Conversely, stimulating bitter taste receptors in SCCs promotes the production of anti-microbial molecules.

Mice without gustducin in their SSCs have a more damaging set of microbes living in their mouths compared to normal mice, implying that the lack of gustducin disconnects the sentinel cells' molecular signal to other systems. Importantly, differences in the oral bacterial composition of the gustducin-less mice compared to normal mice occurred before any loss of bone in the gums, implying that differences in the oral microbiome could be used as a harbinger of disease.