Background
In the present study, the expression and localization of three epithelial peptides (human β-defensin [hBD]-2 and -3, and cathelicidin [LL-37]) are studied in an organotypic dento-epithelial (OD-E) model exposed to Fusobacterium nucleatum (Fn) biofilm.
Conclusion
In our OD-E model, epithelial antimicrobial peptide responses to Fn biofilms have distinct regulation and localization characteristics, resembling those known to occur in the gingival epithelium in vivo.
Methods
Biofilm of Fn ATCC 25586 or AHN 9508 were produced by culturing each strain on semipermeable membranes. The OD-E model was constructed by seeding keratinocytes on fibroblast-containing collagen gels and by placing dentin pieces on the top. A 3-day-old biofilm was placed on the top of the OD-E and the coculture was incubated for 5 hours or 24 hours. Production of epithelial antimicrobial peptides was determined immunohistochemically.
Results
After 5 hours of incubation, the biofilm of each Fn strain stimulated expression of hBD-2 and -3. hBD-2 was localized on superficial layers and hBD-3 on basal cell layers of the epithelium and dento-epithelial junctions, whereas LL-37 was only weakly expressed. After 24 hours, hBD-2 expression was extended toward basal cell layers of the epithelium. In contrast, hBD-3 expression extended toward superficial layers of the epithelium. In the case of Fn AHN 9508 biofilm, LL-37 was localized in the cell layers of the dento-epithelial junction.