Regulation of visfatin by microbial and biomechanical signals in PDL cells

Objectives This in vitro study was established to examine whether visfatin thought to be a link between periodontitis and obesity is produced by periodontal ligament (PDL) cells and, if so, whether its synthesis is modulated by microbial and/or biomechanical signals. Materials and methods PDL cells seeded on BioFlex® plates were exposed to the oral pathogen Fusobacterium nucleatum ATCC 25586 and/or subjected to biomechanical strain for up to 3 days. Gene expression of visfatin and toll-like receptors (TLR) 2 and 4 was analyzed by RT-PCR, visfatin protein synthesis by ELISA and immunocytochemistry, and NFκB nuclear translocation by immunofluorescence. Results F . nucleatum upregulated the visfatin expression in a dose- and time-dependent fashion. Preincubation with neutralizing antibodies against TLR2 and TLR4 caused a significant inhibition of the F . nucleatum -upregulated visfatin expression at 1 day. F . nucleatum stimulated the NFκB nuclear translocation. Biomechanical loading reduced the stimulatory effects of F . nucleatum on visfatin expression at 1 and 3 days and also abrogated the F . nucleatum -induced NFκB nuclear translocation at 60 min. Biomechanical loading inhibited significantly the expression of TLR2 and TLR4 at 3 days. The regulatory effects of F . nucleatum and/or biomechanical loading on visfatin expression were also observed at protein level. Conclusions PDL cells produce visfatin, and this production is enhanced by F . nucleatum . Biomechanical loading seems to be protective against the effects of F . nucleatum on visfatin expression. Clinical relevance Visfatin produced by periodontal tissues could play a major role in the pathogenesis of periodontitis and the interactions with obesity and other systemic diseases.