Treponema denticola is associated with subgingival biofilms in
adult periodontitis and with
acute necrotizing ulcerative gingivitis. However, the molecular mechanisms by which T. denticola impacts periodontal
inflammation and alveolar
bone resorption remain unclear. Here, we examined changes in the host transcriptional profiles during a T. denticola
infection using a murine calvarial model of
inflammation and
bone resorption. T. denticola was injected into the subcutaneous soft tissue over the calvaria of BALB/c mice for 3 days, after which the soft tissues and the calvarial bones were excised.
RNA was isolated and analysed for transcript profiling using Murine GeneChip arrays. Following T. denticola
infection, 2905 and 1234 genes in the infected calvarial bones and soft tissues, respectively, were differentially expressed (P <or= 0.05).
Biological pathways significantly impacted by T. denticola
infection in calvarial bone and calvarial tissue included leukocyte transendothelial migration, cell adhesion (immune system) molecules, cell cycle,
extracellular matrix-receptor interaction, focal adhesion, B-cell receptor signaling and
transforming growth factor-beta signaling pathways resulting in proinflammatory, chemotactic effects, and T-cell stimulation. In conclusion, localized T. denticola
infection differentially induces transcription of a broad array of host genes, the profiles of which differed between inflamed calvarial bone and soft tissues.