Stimulation of Visfatin Production by P. gingivalis and Interleukin-1beta

Objective: This in-vitro study was established to examine the synthesis of visfatin in periodontal ligament (PDL) cells under infectious and inflammatory conditions.

Methods: Human PDL cells were exposed to the proinflammatory cytokine IL-1beta, and the oral periodontopathogens Porphyromonas gingivalis (Pg), Tannerella forsythia (Tf), Treponema denticola (Td), and Aggregatibacter actinomycetemcomitans (Aa) for up to 3 d. The synthesis of visfatin was assessed by real-time PCR, ELISA, and immunocytochemistry. The underlying intracellular mechanisms were studied by pre-incubation with specific inhibitors. ANOVA, Wilcoxon, and Mann-Whitney-U tests were applied (p<0.05).

Results: Whereas Td, Tf, and Aa had no significant effect, Pg increased significantly and dose-dependently the expression of visfatin. Pre-incubation with specific inhibitors against NFkB, JNK or p38 signaling reduced the stimulatory effect of Pg on the visfatin expression by 100%, 87%, and 37%, respectively. Similarly, the visfatin expression was significantly and dose-dependently upregulated by IL-1beta. When cells were pre-incubated with inhibitors against MEK1/2, JNK, NFkB or p38 signaling, the stimulatory effect of IL-1beta on visfatin expression was decreased by 100%, 80%, 78%, and 46%, respectively. The stimulation of visfatin production by Pg and IL-1beta was also observed at protein level.

Conclusions: Visfatin is induced by the periodontopathogen Pg and the proinflammatory cytokine IL-1beta in PDL cells, suggesting that microbial and inflammatory signals can use this adipokine for their detrimental effects on the periodontium. Furthermore, enhanced production of visfatin in the inflamed PDL may contribute to the increased gingival levels of visfatin, as found in periodontitis.