Protein plays key role in infection by oral pathogen

Scientists have discovered that the protein transgultaminase 2 (TG2) is a key component in the process of periodontal disease, according to a new study (Proceedings of the National Academy of Sciences, March 24, 2014).

TG2 is widely distributed inside and outside of human cells. The scientists, from the Forsyth Institute and Northwestern University, found that blocking some associations of TG2 prevents the bacterium Porphyromonas gingivalis from adhering to cells.

P. gingivalis is the major causative agent of periodontitis, and it may also be involved in the development of systemic diseases such as atherosclerosis and rheumatoid arthritis.

The study findings indicate that TG2 is a key mediator in P. gingivalis infection. In this research, the team examined the critical role that TG2 plays in enabling P. gingivalis to adhere to cells. Using confocal microscopes, clusters of TG2 were found where the bacterium was binding to cells. When the team silenced the expression of TG2, P. gingivalis was diminished.

"Once established, Porphyromonas gingivalis is very hard to get rid of," said lead researcher Heike Boisvert, of the department of microbiology at the Forsyth Institute. "The bacterium changes conditions in the surrounding environment to ensure perfect growth; unfortunately, those changes, if untreated, can result in a loss of supportive tissue for our teeth.

The more that is known about the relationship of P. gingivalis with humans, the host, the better scientists can work to prevent disease and disease progression, the researchers noted.

In the next phase of research, Boisvert will be examining TG2-knockout mice to test their susceptibility to P. gingivalis infection and periodontal disease.