Role of dentilisin in Treponema denticola epithelial cell layer penetration

Treponema denticola is an oral anaerobic spirochete implicated in periodontal diseases. The chymotrypsin-like protease, dentilisin (PrtP), has been suggested to be an important virulence factor of T denticola. In this study, we examined the role of dentilisin in T denticola epithelial monolayer penetration by comparing the wild type and prtP mutant. Wild-type T denticola can disrupt transepithelial resistance (TER) and substantially penetrate the HEp-2 cell layer. The prtP mutant altered the monolayer only slightly and penetrated the Hep-2 layer in very low numbers. The membrane fraction of wild-type T denticola is able to complement the prtP mutant in monolayer penetration, while the comparable fraction from the mutant has no such effect. Immunofluorescence studies suggested that wild-type T denticola altered the TER by likely degrading the tight junctional proteins such as ZO-1. Cytotoxicity was not a major factor in the disruption of TER. The outer membrane vesicles (OMVs) of wild-type T denticola also disrupted epithelial barrier function and penetrated the epithelial layers. Taken together, these results suggest that T denticola penetrates the epithelial cell monolayers; by altering cellular tight junctions. (C) 2003 Editions scientifiques et medicales Elsevier SAS. All rights reserved.