Interaction between the human dental microbiome and host gingival model

Objective Interactions between the dental biofilm and host are important to study infectious oral diseases such as dental caries and periodontitis. Previous studies have reported the reaction of a host gingival model cocultured with bacteria or biofilms. However, these studies only report results of a gingival model, and a biofilm cocultured with a gingival model has never been investigated, although the microbiome of dental biofilms is associated with the maintenance of health and the onset of infectious oral diseases. Therefore, we aimed to investigate the reaction of a gingival model and experimental biofilm. An in situ dental biofilm model, which enables biofilm formation in the oral cavity, was used to prepare experimental biofilms. Methods The in situ biofilm was cocultured with a reconstructed human gingival (RHG) model. We performed 16S rRNA sequence analysis, metagenomic function prediction analysis, total bacterial cell counts using quantitative polymerase chain reaction and confocal laser microscopy observation in addition to gene expression and histological investigation of RHG. Results We found a change in Veillonella abundance in the in situ biofilms cocultured with RHG. Metagenomic function prediction analysis revealed that the activity of certain pathways associated with amino acid production, lactic acid fermentation and the glycolysis system significantly increased in biofilms cocultured with RHG. Conclusion The microbiome and functions of dental biofilms can be affected by host gingival tissues. Our findings will contribute to the establishment of a host–biofilm interaction model to understand the pathophysiology of oral infectious diseases.