Establishment of mouse gingival junctional epithelial cell line using a bioengineered tooth system.

Junctional epithelium (JE), one of the constituents of periodontal tissue, has several unique features to prevent bacterial infection. However, the molecular mechanisms of these cells remain to be completely elucidated because there has been no JE cell line to date. We have succeeded in isolating JE cells expressing green fluorescent protein (GFP) by using a bioengineered tooth technique in mice. The gene expressions of GFP-positive JE cells, isolated from around the erupted bioengineered teeth using flow cytometry, were analyzed by RNA sequencing. GFP-positive cells derived from the bioengineered tooth germs showed similar gene expression patterns to primary JE cells. The isolated GFP-positive JE cells were immortalized by transducing the simian virus 40 large T antigen using lentiviral vectors. The established GFP-positive JE cells maintained proliferative activity for more than 20 passages, and did not show cellular senescence as demonstrated by β-galactosidase assay. These cells also expressed similar gene expression patterns to primary JE cells. The established cell lines may prove useful for future investigation of JE characteristics in vitro.