title: Treponema denticola invasion into human gingival epithelial cells.
abstract: Host cell invasion is important for periodontal pathogens in evading host defenses and spreading into deeper areas of the periodontal tissue. Treponema denticola has been implicated in a number of potentially pathogenic processes, including periodontal tissue penetration. Here we tested the ability of T. denticola strains to invade human gingival epithelial cells (HGEC). After 2 h infection, intracellular location of T. denticola cells was confirmed by confocal laser scanning microscopy (CLSM). Results from an antibiotic protection assay following [(3)H]uridine labeling indicated that invasion efficiency reached a maximum at 2 h after infection. Internalized T. denticola cells were still observed in HGEC at 24 h by CLSM. A dentilisin deficient mutant exhibited significantly decreased invasion (p < 0.05) compared with the wild-type strain. In inhibition assays, phenylmethylsulfonyl fluoride and metabolic inhibitors such as methyl-β-cyclodextrin and staurosporine significantly reduced T. denticola invasion. Under CLSM, T. denticola colocalized with GM-1 ganglioside-containing membrane microdomains in a cholesterol-dependent manner. These results indicated that T. denticola has the ability to invade into and survive within HGECs. Dentilisin activity of T. denticola and lipid rafts on HGEC appear to play important roles in this process.
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Inagaki
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan.
authors.forename: Ryuta
authors.initials: R
authors.lastname: Kimizuka
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan.
authors.forename: Eitoyo
authors.initials: E
authors.lastname: Kokubu
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Periodontology, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Saito
authors.affiliation: Oral Health Science Center, Tokyo Dental College, 2-9-18 Misaki-cho, Chiyoda-ku, Tokyo 101-0064, Japan; Department of Microbiology, Tokyo Dental College, 2-1-14 Misaki-cho, Chiyoda-ku, Tokyo 101-0061, Japan. Electronic address: ishihara@tdc.ac.jp.
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Ishihara
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004847:Epithelial Cells / Q000382:microbiology* / Q000473:pathology; D005881:Gingiva / Q000382:microbiology* / Q000473:pathology*; D006790:Host-Parasite Interactions; D006801:Humans; D021962:Membrane Microdomains / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D010447:Peptide Hydrolases / Q000172:deficiency / Q000378:metabolism; D010518:Periodontitis / Q000382:microbiology; D010664:Phenylmethylsulfonyl Fluoride / Q000494:pharmacology; D013145:Spirochaetales Infections / Q000382:microbiology*; D019311:Staurosporine / Q000494:pharmacology; D048373:Treponema denticola / Q000187:drug effects / Q000201:enzymology / Q000472:pathogenicity*; D047392:beta-Cyclodextrins / Q000494:pharmacology
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D047392:beta-Cyclodextrins; C108732:methyl-beta-cyclodextrin; D010664:Phenylmethylsulfonyl Fluoride; D010447:Peptide Hydrolases; C102570:dentilisin; D019311:Staurosporine
keywords: Gingival epithelial cell; Invasion; Periodontitis; Protease; Spirochetes