Researchers from Tokyo Medical and Dental University have discovered that Aggregatibacter actinomycetemcomitans, a bacterium known to cause gum disease, can exacerbate rheumatoid arthritis (RA).
Published on August 15, the study used mice to examine this link and found that infection with this bacterium triggers an immune response that aggravates arthritis symptoms.
Previous clinical studies have shown that A. actinomycetemcomitans is associated with “aggressive periodontitis,” an inflammation of the tissue surrounding the teeth, and may potentially worsen RA. However, the exact mechanism remained unclear until this study.
Key player protein
The researchers identified a key player in this process: a protein called caspase-11. When A. actinomycetemcomitans is present, caspase-11 activates the inflammasome, a group of proteins within immune cells that leads to increased inflammation in the joints. This heightened inflammation exacerbates arthritis symptoms.
Interestingly, when the researchers blocked caspase-11 or employed treatments to reduce inflammasome activity, the mice experienced significantly milder arthritis symptoms.
“Joint swelling and immune cell infiltration were notably lower in caspase-11-deficient mice compared to wild-type mice following A. actinomycetemcomitans infection,” the study notes.
This finding suggests that targeting this pathway could offer a new approach to treating or managing rheumatoid arthritis, particularly in patients with concurrent gum disease.
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