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 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 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 Identification of Porphyromonas gingivalis Genes Specifically Expressed in Human Gingival Epithelial Cells by Using Differential Display Reverse Transcription-PCR

2004 ◽  
Vol 72 (7) ◽  
pp. 3752-3758 ◽  
Author(s):  
Yoonsuk Park ◽  
Özlem Yilmaz ◽  
Il-Young Jung ◽  
Richard J. Lamont
Keyword(s):  
Epithelial Cells ◽  
Porphyromonas Gingivalis ◽  
Abc Transporter ◽  
Differential Display ◽  
Molecular Mechanisms ◽  
Gene Products ◽  
Reverse Transcription Pcr ◽  
Gingival Epithelial Cells ◽  
Insertional Inactivation ◽  
Human Gingival Epithelial Cells

ABSTRACT Porphyromonas gingivalis, one of the causative agents of adult periodontitis, can invade and survive within host epithelial cells. The molecular mechanisms by which P. gingivalis induces uptake and adapts to an intracellular environment are not fully understood. In this study, we have investigated the genetic responses of P. gingivalis internalized within human gingival epithelial cells (GECs) in order to identify factors involved in invasion and survival. We compared the differential display of arbitrarily PCR-amplified gene transcripts in P. gingivalis recovered from GECs with the display of transcripts in P. gingivalis control cultures. Over 20 potential differentially expressed transcripts were identified. Among these, pepO, encoding an endopeptidase, and genes encoding an ATP-binding cassette (ABC) transporter and a cation-transporting ATPase were upregulated in GECs. To investigate the functionality of these gene products, mutants were generated by insertional inactivation. Compared to the parental strain, mutants of each gene showed a significant reduction in their invasion capabilities. In addition, GEC cytoskeletal responses to the mutants were distinct from those induced by the parent. In contrast, adhesion of the mutant strains to GECs was not affected by lack of expression of the gene products. These results suggest that PepO, a cation-transporting ATPase, and an ABC transporter are required for the intracellular lifestyle of P. gingivalis.

scholarly journals Campylobacter jejuni Drives MyD88-Independent Interleukin-6 Secretion via Toll-Like Receptor 2

2009 ◽  
Vol 77 (4) ◽  
pp. 1553-1560 ◽  
Author(s):  
Lorna M. Friis ◽  
Monika Keelan ◽  
Diane E. Taylor
Keyword(s):  
Epithelial Cells ◽  
Campylobacter Jejuni ◽  
Interleukin 6 ◽  
Fluid Transport ◽  
Gastrointestinal Disease ◽  
Primary Response ◽  
Intestinal Epithelial ◽  
Toll Like Receptor ◽  
Independent Manner ◽  
Toll Like Receptor 2

ABSTRACT Gastrointestinal disease caused by Campylobacter jejuni is characterized by localized inflammation and the destruction of the epithelial cell barrier that forms host innate protection against pathogens. This can lead to an imbalance in fluid transport across the gastrointestinal tract, resulting in severe diarrhea. The mechanisms of host cell receptor recognition of C. jejuni and downstream immune signaling pathways leading to this inflammatory disease, however, remain unclear. The aim of this study was to analyze the mechanisms involved in C. jejuni induction of the acute-phase inflammatory response regulator interleukin-6 (IL-6). Polarized intestinal epithelial Caco-2 monolayers responded to infections with Salmonella enterica serovar Typhimurium and eight isolates of C. jejuni by an increase in levels of expression and secretion of IL-6. No such IL-6 response, however, was produced upon infection with the human commensal organism Lactobacillus rhamnosus GG. The IL-6 signaling pathway was further characterized using short interfering RNA complexes to block gene expression. The inhibition of myeloid differentiation primary response protein 88 (MyD88) expression in this manner did not affect C. jejuni-induced IL-6 secretion, suggesting a MyD88-independent route to IL-6 signal transduction in C. jejuni-infected human epithelial cells. However, a significant reduction in levels of IL-6 was evident in the absence of Toll-like receptor 2 (TLR-2) expression, implying a requirement for TLR-2 in C. jejuni recognition. Caco-2 cells were also treated with heat-inactivated and purified membrane components of C. jejuni to isolate the factor responsible for triggering IL-6 signaling. The results demonstrate that C. jejuni surface polysaccharides induce IL-6 secretion from intestinal epithelial cells via TLR-2 in a MyD88-independent manner.

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