scholarly journals Treponema denticola Suppresses Expression of Human β-Defensin-3 in Gingival Epithelial Cells through Inhibition of the Toll-Like Receptor 2 Axis

2009 ◽  
Vol 78 (2) ◽  
pp. 672-679 ◽  
Author(s):  
Ji Eun Shin ◽  
Young Sook Kim ◽  
Ju-Eun Oh ◽  
Byung-Moo Min ◽  
Youngnim Choi
Keyword(s):  
Epithelial Cells ◽  
Suppressive Effect ◽  
Inhibitory Effect ◽  
Mitogen Activated Protein Kinase ◽  
Treponema Denticola ◽  
Toll Like Receptor ◽  
Periodontal Pathogens ◽  
Gingival Epithelial Cells ◽  
Toll Like Receptor 2 ◽  
Human Gingival Epithelial Cells

ABSTRACT We reported previously that Treponema denticola, one of the periodontal pathogens, suppresses the expression of human β-defensins (HBDs) in human gingival epithelial cells. To identify the mechanisms involved in this suppression, immortalized and normal human gingival epithelial cells were infected with live or heat-killed T. denticola for 24 h, and then the expression of HBDs was examined by real-time RT-PCR. Live T. denticola suppressed the expression of HBD-3 substantially and also suppressed the expression of HBD-1 and HBD-2. However, heat-killed bacteria did not produce a suppressive effect but instead slightly upregulated the levels of HBD-2 and HBD-3. In contrast to live T. denticola, which reduced the activation of mitogen-activated protein kinase (MAPK) and NF-κB within an hour of infection, heat-killed bacteria did not show any inhibitory effect on the MAPK and NF-κB signaling pathways. Knockdown of Toll-like receptor 2 (TLR2) via RNA interference abolished the suppressive effect of T. denticola on the expression of HBD-3. Heat-killed T. denticola but not live bacteria could activate TLR2 in CHO/CD14/TLR2 reporter cells, suggesting that T. denticola contains a heat-labile inhibitor(s) of TLR2 in addition to ligands recognized by TLR2. Indeed, live T. denticola was able to inhibit TLR2 activation by Pam3CSK. In conclusion, T. denticola suppressed the expression of HBD-3 by inhibiting the TLR2 axis in gingival epithelial cells. These results may provide new insight into the pathogenesis of periodontitis caused by T. denticola.

scholarly journals Oral Treponemes and Their Outer Membrane Extracts Activate Human Gingival Epithelial Cells through Toll-Like Receptor 2

2003 ◽  
Vol 71 (2) ◽  
pp. 717-725 ◽  
Author(s):  
Yasuyuki Asai ◽  
Takayoshi Jinno ◽  
Tomohiko Ogawa
Keyword(s):  
Monoclonal Antibody ◽  
Epithelial Cells ◽  
Mrna Expression ◽  
Outer Membrane ◽  
Periodontal Diseases ◽  
Treponema Denticola ◽  
Toll Like Receptor ◽  
Gingival Epithelial Cells ◽  
Toll Like Receptor 2 ◽  
Human Gingival Epithelial Cells

ABSTRACT Oral treponemes are considered to be important in the development and progression of periodontal diseases. We investigated the mechanisms of recognition and activation of human gingival epithelial cells (HGEC) with the oral treponemes Treponema denticola, Treponema vincentii, and Treponema medium and their outer membrane extracts (OMEs). T. vincentii and T. medium but not T. denticola produced interleukin 8 (IL-8) in an HGEC culture. Further, all three treponemes induced IL-8 mRNA expression and NF-κB activation in HGEC. Among them, T. denticola especially exhibited trypsin- and chymotrypsin-like protease activities, and the addition of chymostatin, a chymotrypsin protease inhibitor, resulted in detectable IL-8 production by HGEC cultured with T. denticola. Additionally, IL-8 mRNA expression in HGEC cultured with the three treponemes and their OMEs was definitely inhibited by the mouse anti-human Toll-like receptor 2 (TLR2) monoclonal antibody TL2.1. These findings suggest that oral treponemes and their OMEs activate HGEC through TLR2.

scholarly journals Toll-Like Receptor 2-Mediated Interleukin-8 Expression in Gingival Epithelial Cells by the Tannerella forsythia Leucine-Rich Repeat Protein BspA

2007 ◽  
Vol 76 (1) ◽  
pp. 198-205 ◽  
Author(s):  
Shinsuke Onishi ◽  
Kiyonobu Honma ◽  
Shuang Liang ◽  
Panagiota Stathopoulou ◽  
Denis Kinane ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Interleukin 8 ◽  
Host Cells ◽  
Leucine Rich Repeat ◽  
Toll Like Receptor ◽  
Periodontal Pathogens ◽  
Tannerella Forsythia ◽  
Multifunctional Protein ◽  
Gingival Epithelial Cells ◽  
Human Gingival Epithelial Cells

ABSTRACT Tannerella forsythia is a gram-negative anaerobe strongly associated with chronic human periodontitis. This bacterium expresses a cell surface-associated and secreted protein, designated BspA, which has been recognized as an important virulence factor. The BspA protein belongs to the leucine-rich repeat (LRR) and bacterial immunoglobulin-like protein families. BspA is, moreover, a multifunctional protein which interacts with a variety of host cells, including monocytes which appear to respond to BspA through Toll-like receptor (TLR) signaling. Since gingival epithelium forms a barrier against periodontal pathogens, this study was undertaken to determine if gingival epithelial cells respond to BspA challenge and if TLRs play any role in BspA recognition. This study was also directed towards identifying the BspA domains responsible for cellular activation. We provide direct evidence for BspA binding to TLR2 and demonstrate that the release of the chemokine interleukin-8 from human gingival epithelial cells by BspA is TLR2 dependent. Furthermore, the LRR domain of BspA is involved in activation of TLR2, while TLR1 serves as a signaling partner. Thus, our findings suggest that BspA is an important modulator of host innate immune responses through activation of TLR2 in cooperation with TLR1.

scholarly journals Treponema denticola Activates Mitogen-Activated Protein Kinase Signal Pathways through Toll-Like Receptor 2

2007 ◽  
Vol 75 (12) ◽  
pp. 5763-5768 ◽  
Author(s):  
John Ruby ◽  
Kunal Rehani ◽  
Michael Martin
Keyword(s):  
Protein Kinase ◽  
Mapk Signaling ◽  
Innate Immune ◽  
Mitogen Activated Protein Kinase ◽  
Signal Pathways ◽  
Treponema Denticola ◽  
Toll Like Receptor ◽  
Extracellular Signal ◽  
Mitogen Activated Protein ◽  
Toll Like Receptor 2

ABSTRACT Treponema denticola, a spirochete indigenous to the oral cavity, is associated with host inflammatory responses to anaerobic polymicrobial infections of the root canal, periodontium, and alveolar bone. However, the cellular mechanisms responsible for the recognition of T. denticola by the innate immune system and the underlying cell signaling pathways that regulate the inflammatory response to T. denticola are currently unresolved. In this study, we demonstrate that T. denticola induces innate immune responses via the utilization of Toll-like receptor 2 (TLR2) but not TLR4. Assessment of TLR2/1 and TLR2/6 heterodimers revealed that T. denticola predominantly utilizes TLR2/6 for the induction of cellular responses. Analysis of the mitogen-activated protein kinase (MAPK) signaling pathway in T. denticola-stimulated monocytes identified a prolonged up-regulation of the MAPK extracellular signal-related kinase 1/2 (ERK1/2) and p38, while no discernible increase in phospho-c-Jun N-terminal kinase 1/2 (JNK1/2) levels was observed. With the aid of pharmacological inhibitors selectively targeting ERK1/2 via the mitogen-activated protein kinase/extracellular signal-related kinase 1/2 kinase and p38, we further demonstrate that ERK1/2 and p38 play a major role in T. denticola-mediated pro- and anti-inflammatory cytokine production.

scholarly journals Treponema denticola invasion into human gingival epithelial cells

2016 ◽  
Vol 94 ◽  
pp. 104-111 ◽  
Author(s):  
Satoru Inagaki ◽  
Ryuta Kimizuka ◽  
Eitoyo Kokubu ◽  
Atsushi Saito ◽  
Kazuyuki Ishihara
Keyword(s):  
Epithelial Cells ◽  
Treponema Denticola ◽  
Gingival Epithelial Cells ◽  
Human Gingival Epithelial Cells

scholarly journals Toll-Like Receptor 2 and NALP2 Mediate Induction of Human Beta-Defensins by Fusobacterium nucleatum in Gingival Epithelial Cells

2008 ◽  
Vol 77 (3) ◽  
pp. 1044-1052 ◽  
Author(s):  
Suk Ji ◽  
Ji Eun Shin ◽  
Young Sook Kim ◽  
Ju-Eun Oh ◽  
Byung-Moo Min ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Fusobacterium Nucleatum ◽  
Enzyme Linked Immunosorbent Assay ◽  
Toll Like Receptor ◽  
Jnk Signaling ◽  
Reverse Transcription Pcr ◽  
Pyrin Domain ◽  
Gingival Epithelial Cells ◽  
Toll Like Receptor 2 ◽  
Beta Defensins

ABSTRACT We previously reported that infection by Fusobacterium nucleatum strongly induced the expression of both human beta-defensin 2 (HBD-2) and HBD-3 by gingival epithelial cells. The aim of this study was to characterize the pattern recognition receptors (PRRs) and regulatory mechanisms involved in the induction of HBD-2 and -3 expression by F. nucleatum in gingival epithelial cells. Immortalized human gingival epithelial HOK-16B cells were infected with live or heat-killed F. nucleatum, and the expression of HBDs and interleukin-8 (IL-8) was examined by real-time reverse transcription-PCR and enzyme-linked immunosorbent assay, respectively. Live, but not heat-killed, F. nucleatum invaded HOK-16B cells, as seen by confocal microscopy and flow cytometry. Live F. nucleatum induced both HBD-2 and -3 efficiently, whereas heat-killed bacteria induced only HBD-3 at a reduced level. Knockdown of NACHT-LRR- and pyrin domain-containing protein 2 (NALP2), the most abundant intracellular PRR in HOK-16B cells, by RNA interference (RNAi) significantly reduced the induction of HBD-3 but not HBD-2 and IL-8. In addition, knockdown of Toll-like receptor 2 (TLR2) by RNAi reduced the upregulation of HBD-2 and -3 but not IL-8. Heat-killed F. nucleatum was hindered in its ability to activate TLR2 and JNK signaling pathways. Theses data show that TLR2 and NALP2 mediate the induction of HBDs by F. nucleatum in gingival epithelial cells, but thresholds for the two HBD genes are different.

scholarly journals Bacterial Fimbriae and Their Peptides Activate Human Gingival Epithelial Cells through Toll-Like Receptor 2

2001 ◽  
Vol 69 (12) ◽  
pp. 7387-7395 ◽  
Author(s):  
Yasuyuki Asai ◽  
Yoshinori Ohyama ◽  
Keika Gen ◽  
Tomohiko Ogawa
Keyword(s):  
Epithelial Cells ◽  
Lipid A ◽  
Periodontal Diseases ◽  
Host Responses ◽  
Central Component ◽  
Toll Like Receptor ◽  
Common Component ◽  
Fimbrial Subunit ◽  
Gingival Epithelial Cells ◽  
Human Gingival Epithelial Cells

ABSTRACT Gingival epithelial cells are a central component of the barrier between oral microflora and internal tissues. Host responses to periodontopathic bacteria and surface components containing fimbriae are thought to be important in the development and progression of periodontal diseases. To elucidate this mechanism, we established immortalized human gingival epithelial cells (HGEC) that were transfected with human papillomavirus. HGEC predominantly expressed Toll-like receptor (TLR) 2, but not TLR4 or CD14. They also induced interleukin-8 (IL-8) production when stimulated withPorphyromonas gingivalis fimbriae andStaphylococcus aureus peptidoglycan, but notEscherichia coli-type synthetic lipid A. Furthermore, an active synthetic peptide composed of residues 69 to 73 (ALTTE) of the fimbrial subunit protein, derived from P. gingivalis and similar to a common component of cell wall peptidoglycans in parasitic bacteria,N-acetylmuramyl-l-alanyl-d-isoglutamine (MDP), significantly induced IL-8 production and NF-κB activation in HGEC, and these cytokine-producing activities were augmented by a complex of soluble CD14 and lipopolysaccharide-binding protein (LBP). IL-8 production in HGEC stimulated with these bacterial components was clearly inhibited by mouse monoclonal antibody to human TLR2. These findings suggest that P. gingivalis fimbrial protein and its active peptide are capable of activating HGEC through TLR2.

Possible requirement of intercellular adhesion molecule-1 for invasion of gingival epithelial cells byTreponema medium

2007 ◽  
Vol 53 (11) ◽  
pp. 1232-1238 ◽  
Author(s):  
Riyoko Tamai ◽  
Yasuyuki Asai ◽  
Atsushi Kawabata ◽  
Toshitaka Akisaka ◽  
Tomohiko Ogawa
Keyword(s):  
Epithelial Cells ◽  
Adhesion Molecule ◽  
Periodontal Diseases ◽  
Intercellular Adhesion ◽  
Intercellular Adhesion Molecule ◽  
Intercellular Adhesion Molecule 1 ◽  
Principal Role ◽  
Gingival Epithelial Cells ◽  
Toll Like Receptor 2 ◽  
Human Gingival Epithelial Cells

Oral treponemes are members of the spirochete family of bacteria associated with periodontal diseases. In the present study, we demonstrate that intercellular adhesion molecule-1 (ICAM-1) on human gingival epithelial cells (HGEC) contributed to the invasion of Treponema medium , a medium-sized oral Treponema, into those cells. The quantity of T. medium in HGEC was found to peak at 2 h after inoculation and then decreased gradually. Immunofluorescence microscopy findings showed that the bacteria were colocalized with ICAM-1 on HGEC. Furthermore, knockdown of ICAM-1 in HGEC resulted in inhibition of T. medium invasion by RNA interference, whereas that of Toll-like receptor 2 did not. These results suggest that ICAM-1 may be required for the invasion of T. medium into HGEC, and they indicate that the molecule plays a principal role in the primary stages of the development and progression of chronic periodontitis.

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