Induction of Toll‐Like Receptor Expression by Porphyromonas gingivalis |
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| Authors: | Nawarat Wara‐aswapati Anek Chayasadom Rudee Surarit Waranuch Pitiphat Jason A. Boch Toshiyuki Nagasawa Isao Ishikawa Yuichi Izumi |
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| Affiliation: | 1. Department of Periodontology, Faculty of Dentistry, Khon Kaen University, Khon Kaen, Thailand.;2. Research Group of Chronic Inflammatory Oral Diseases and Systemic Diseases Associated with Oral Health, Khon Kaen University.;3. Department of Oral Biology, Faculty of Dentistry, Mahidol University, Bangkok, Thailand.;4. Department of Community Dentistry, Faculty of Dentistry, Khon Kaen University.;5. Department of Oral Medicine, Infection and Immunity, Harvard School of Dental Medicine, Boston, MA.;6. Division of Periodontology and Endodontology, School of Dentistry, Health Sciences University of Hokkaido, Hokkaido, Japan.;7. Institute of Advanced Biomedical Engineering and Science, Tokyo Women's Medical University, Tokyo, Japan.;8. Department of Hard Tissue Engineering, Faculty of Dentistry, Tokyo Medical and Dental University, Tokyo, Japan.;9. Global Center of Excellence Program, International Research Center for Molecular Science in Tooth and Bone Diseases, Tokyo Medical and Dental University. |
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| Abstract: | Background: Toll‐like receptors (TLRs) play pivotal roles in host immune responses and have been suggested to be involved in the development of many infectious diseases. In this study, the mRNA expression levels of TLR2, TLR4, and TLR9 and their relationship with periodontopathic bacteria in periodontal tissue are examined. Furthermore, the mechanism of TLR induction by Porphyromonas gingivalis is investigated in human gingival fibroblasts (HGFs). Methods: Gingival tissue and subgingival plaque samples were collected from 19 patients with chronic periodontitis (CP) and 16 control individuals without periodontitis. Gene expression levels in the tissues and in HGFs were analyzed by reverse transcription‐polymerase chain reaction (RT‐PCR). The numbers of periodontopathic bacteria were determined by quantitative real‐time PCR. Results: The expression levels of TLR2 and TLR9 were significantly higher in the tissues of patients with CP compared to the tissues of control individuals. The mRNA levels of TLR2 and TLR9, but not TLR4, were positively correlated with the number of P. gingivalis in subgingival plaque. P. gingivalis sonicated extract, P. gingivalis lipopolysaccharide, P. gingivalis DNA, and tumor necrosis factor‐α(TNF‐α) could significantly upregulate the mRNA expression of TLR2 in HGFs. Furthermore, P. gingivalis–mediated TLR2 expression was suppressed by TNF‐α antibody. Conclusions: This study suggests that P. gingivalis infection induces TLR2 and TLR9 upregulation in patients with CP. P. gingivalis–induced TLR2 expression in HGFs is partially dependent on TNF‐α and may lead to sensitization of HGFs to bacterial components encountered in the periodontal microenvironment. |
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| Keywords: | Chronic periodontitis fibroblasts Porphyromonas gingivalis Toll‐like receptor 2 tumor necrosis factor‐alpha |
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