Human gingival epithelial cells produce chemotactic factors interleukin-8 and monocyte chemoattractant protein-1 after stimulation with Porphyromonas gingivalis via toll-like receptor 2.
BACKGROUND
The mechanism of stimulation of human gingival epithelial cells (HGEC) by Porphyromonas gingivalis (Pg) has not been fully clarified yet. In order to investigate the possible activation of HGEC by Pg through Toll-like receptors (TLRs), we analyzed the production of chemotactic factors and the activated nuclear factor-kappa B (NF-kappaB).


METHODS
The mRNA expression of TLRs and the protein expression of TLR2 and TLR4 in HGEC and gingival tissue were assessed using reverse transcription-polymerase chain reaction (RT-PCR) assay and immunohistochemical staining. Primary cultured HGEC (nHGEC) and HGEC transformed by simian virus 40 T antigen (OBA-9) were activated by a sonic extract (SE) of Pg to examine cytokine production and NF-kappaB activation using enzyme-linked immunosorbant assay (ELISA). In addition, Pg mediated activation of NF-kappaB in a TLR2-transfectant was also investigated.


RESULTS
RT-PCR results revealed that HGEC expressed mRNA of TLR2, TLR4, TLR5, and TLR9, although the expression profiles of each cell line were slightly different. In addition, immunostaining revealed the prominent expression of TLR2 not only in nHGEC, but also in the gingival epithelium of the tissue specimen. Interestingly, nHGEC and OBA-9 secreted IL-8 and monocyte chemoattractant protein (MCP)-1 upon stimulation with Pg SE more efficiently than LPS and fimbriae of Pg. Furthermore, Pg SE increased the activated NF-kappaB not only in OBA-9, but also in 293T cells transfected with the human TLR2 gene.


CONCLUSIONS
TLR2 participates, at least partly, in the signaling pathway to induce chemokine production in gingival epithelium as a reaction against Pg component(s), probably other than lipopolysaccharide and fimbriae.
Kusumoto
Yutaka
Y
Department of Periodontology, Division of Oral Biology and Disease Control, Osaka University Graduate School of Dentistry, Osaka, Japan.
Hirano
Hiroyuki
H
Saitoh
Keiko
K
Yamada
Satoru
S
Takedachi
Masahide
M
Nozaki
Takenori
T
Ozawa
Yasuhiro
Y
Nakahira
You
Y
Saho
Teruyuki
T
Ogo
Hideji
H
Shimabukuro
Yoshio
Y
Okada
Hiroshi
H
Murakami
Shinya
S
D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000276:immunology; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000276:immunology*; D004396:Coloring Agents; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D010861:Fimbriae, Bacterial / Q000276:immunology; D005881:Gingiva / Q000276:immunology* / Q000382:microbiology; D006801:Humans; D016209:Interleukin-8 / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D008562:Membrane Glycoproteins / Q000276:immunology*; D016328:NF-kappa B / Q000276:immunology; D016966:Porphyromonas gingivalis / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis; D011956:Receptors, Cell Surface / Q000276:immunology*; D015398:Signal Transduction; D018709:Statistics, Nonparametric; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors; D014162:Transfection; D014170:Transformation, Genetic / Q000235:genetics
D000952:Antigens, Polyomavirus Transforming; D018932:Chemokine CCL2; D004396:Coloring Agents; D016209:Interleukin-8; D008070:Lipopolysaccharides; D008562:Membrane Glycoproteins; D016328:NF-kappa B; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C495346:TLR5 protein, human; C495371:TLR9 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051198:Toll-Like Receptor 5; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors