Expression of Inflammatory Cytokine Genes In Vivo by Human Alveolar Bone-Derived Polymorphonuclear Leukocytes Isolated from Chronically Inflamed Sites of Bone Resorption

ABSTRACT Biofilm formation by the periodontal pathogen Aggregatibacter actinomycetemcomitans is dependent upon autoinducer-2 (AI-2)-mediated quorum sensing. However, the components that link the detection of the AI-2 signal to downstream gene expression have not been determined. One potential regulator is the QseBC two-component system, which is part of the AI-2-dependent response pathway that controls biofilm formation in Escherichia coli. Here we show that the expression of QseBC in A. actinomycetemcomitans is induced by AI-2 and that induction requires the AI-2 receptors, LsrB and/or RbsB. Additionally, inactivation of qseC resulted in reduced biofilm growth. Since the ability to grow in biofilms is essential for A. actinomycetemcomitans virulence, strains that were deficient in QseC or the AI-2 receptors were examined in an in vivo mouse model of periodontitis. The ΔqseC mutant induced significantly less alveolar bone resorption than the wild-type strain (P < 0.02). Bone loss in animals infected with the ΔqseC strain was similar to that in sham-infected animals. The ΔlsrB, ΔrbsB, and ΔlsrB ΔrbsB strains also induced significantly less alveolar bone resorption than the wild type (P < 0.03, P < 0.02, and P < 0.01, respectively). However, bone loss induced by a ΔluxS strain was indistinguishable from that induced by the wild type, suggesting that AI-2 produced by indigenous microflora in the murine oral cavity may complement the ΔluxS mutation. Together, these results suggest that the QseBC two-component system is part of the AI-2 regulon and may link the detection of AI-2 to the regulation of downstream cellular processes that are involved in biofilm formation and virulence of A. actinomycetemcomitans.

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Bone Resorption Caused by Three Periodontal Pathogens In Vivo in Mice Is Mediated in Part by Prostaglandin

Infection and Immunity ◽

10.1128/iai.66.9.4158-4162.1998 ◽

1998 ◽

Vol 66 (9) ◽

pp. 4158-4162 ◽

Cited By ~ 50

Author(s):

Yuval Zubery ◽

Colin R. Dunstan ◽

Beryl M. Story ◽

Lakshmyya Kesavalu ◽

Jeffrey L. Ebersole ◽

...

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Alveolar Bone ◽

Tissue Injury ◽

Bone Destruction ◽

Fusobacterium Nucleatum ◽

Host Responses ◽

Periodontal Pathogens ◽

Tissue Destruction

ABSTRACT Gingival inflammation, bacterial infection, alveolar bone destruction, and subsequent tooth loss are characteristic features of periodontal disease, but the precise mechanisms of bone loss are poorly understood. Most animal models of the disease require injury to gingival tissues or teeth, and the effects of microorganisms are thus complicated by host responses to tissue destruction. To determine whether three putative periodontal pathogens, Porphyromonas gingivalis, Campylobacter rectus, andFusobacterium nucleatum, could cause localized bone resorption in vivo in the absence of tissue injury, we injected live or heat-killed preparations of these microorganisms into the subcutaneous tissues overlying the calvaria of normal mice once daily for 6 days and then examined the bones histologically. We found that all three microorganisms (both live and heat killed) stimulated bone resorption and that the strain of F. nucleatum used appeared to be the strongest inducer of osteoclast activity. Treatment of the mice concomitantly with indomethacin reduced but did not completely inhibit bone resorption by these microorganisms, suggesting that their effects were mediated, in part, by arachidonic acid metabolites (e.g., prostaglandins). Our findings indicate that these potential pathogens can stimulate bone resorption locally when placed beside a bone surface in vivo in the absence of prior tissue injury and support a role for them in the pathogenesis of bone loss around teeth in periodontitis.

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Gamma Interferon (IFN-γ) and IFN-γ-Inducing Cytokines Interleukin-12 (IL-12) and IL-18 Do Not Augment Infection-Stimulated Bone Resorption In Vivo

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.11.1.106-110.2004 ◽

2004 ◽

Vol 11 (1) ◽

pp. 106-110 ◽

Cited By ~ 36

Author(s):

Hajime Sasaki ◽

Khaled Balto ◽

Nobuyuki Kawashima ◽

Jean Eastcott ◽

Katsuaki Hoshino ◽

...

Keyword(s):

Bone Resorption ◽

Alveolar Bone ◽

Interleukin 1 ◽

Bone Destruction ◽

Gamma Interferon ◽

Interleukin 12 ◽

Wild Type ◽

Necrosis Factor Alpha ◽

Ifn Γ

ABSTRACT Periapical granulomas are induced by bacterial infection of the dental pulp and result in destruction of the surrounding alveolar bone. In previous studies we have reported that the bone resorption in this model is primarily mediated by macrophage-expressed interleukin-1 (IL-1). The expression and activity of IL-1 is in turn modulated by a network of Th1 and Th2 regulatory cytokines. In the present study, the functional roles of the Th1 cytokine gamma interferon (IFN-γ) and IFN-γ-inducing cytokines IL-12 and IL-18 were determined in a murine model of periapical bone destruction. IL-12−/−, IL-18−/−, and IFN-γ−/− mice were subjected to surgical pulp exposure and infection with a mixture of four endodontic pathogens, and bone destruction was determined by microcomputed tomography on day 21. The results indicated that all IL-12−/−, IL-18−/−, and IFN-γ−/− mice had similar infection-stimulated bone resorption in vivo as wild-type control mice. Mice infused with recombinant IL-12 also had resorption similar to controls. IFN-γ−/− mice exhibited significant elevations in IL-6, IL-10, IL-12, and tumor necrosis factor alpha in lesions compared to wild-type mice, but these modulations had no net effect on IL-1α levels. Recombinant IL-12, IL-18, and IFN-γ individually failed to consistently modulate macrophage IL-1α production in vitro. We conclude that, at least individually, endogenous IL-12, IL-18, and IFN-γ do not have a significant effect on the pathogenesis of infection-stimulated bone resorption in vivo, suggesting possible functional redundancy in proinflammatory pathways.

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The Possible Role of Neutrophils in the Induction of Osteoclastogenesis

Journal of Immunology Research ◽

10.1155/2019/8672604 ◽

2019 ◽

Vol 2019 ◽

pp. 1-14 ◽

Cited By ~ 1

Author(s):

Carolyn G. J. Moonen ◽

Teun J. de Vries ◽

Patrick Rijkschroeff ◽

Patrice E. Poubelle ◽

Elena A. Nicu ◽

...

Keyword(s):

Bone Resorption ◽

Polymorphonuclear Leukocytes ◽

Alveolar Bone ◽

Surface Expression ◽

Rankl Expression ◽

Experimental Conditions ◽

Periodontal Tissues ◽

Immune Mediators ◽

Receptor Activator

The ligand of the receptor activator of NF-κB (RANKL) is a key molecule in the formation of osteoclasts, the key cells that cause the disease-associated alveolar bone resorption in periodontitis. We hypothesized that polymorphonuclear leukocytes (PMNs), found as the most prominent cells of inflamed periodontal tissues, could play an important role in providing signals to trigger osteoclastogenesis and thus activating pathological bone resorption in periodontitis. RANKL expression was investigated on circulatory PMNs (cPMNs) and oral PMNs (oPMNs) taken from both controls and periodontitis patients. On average, 2.3% and 2.4% RANKL expression was detected on the cPMNs and oPMNs from periodontitis patients, which did not differ significantly from healthy controls. Since cPMNs may acquire a more osteoclastogenesis-facilitating phenotype while migrating into the inflamed periodontium, we next investigated whether stimulated (with LPS, TNF-α, or IL-6) cPMNs have the capacity to contribute to osteoclastogenesis. Enduring surface expression of RANKL for short-lived cells as cPMNs was achieved by fixating stimulated cPMNs. RANKL expression on stimulated cPMNs, as assessed by flow cytometry and immunohistochemistry, was limited (6.48±0.72%,mean expression±SEM) after 24 and 48 hours of stimulation with LPS. Likewise, stimulation with TNF-αand IL-6 resulted in limited RANKL expression levels. These limited levels of expression did not induce osteoclastogenesis when cocultured with preosteoclasts for 10 days. We report that, under the aforementioned experimental conditions, neither cPMNs nor oPMNs directly induced osteoclastogenesis. Further elucidation of the key cellular players and immune mediators that stimulate alveolar bone resorption in periodontitis will help to unravel its pathogenesis.

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A peptide derived from rice inhibits alveolar bone resorption via suppression of inflammatory cytokine production

Journal of Periodontology ◽

10.1002/jper.18-0630 ◽

2019 ◽

Vol 90 (10) ◽

pp. 1160-1169 ◽

Cited By ~ 2

Author(s):

Yukari Aoki‐Nonaka ◽

Koichi Tabeta ◽

Mai Yokoji ◽

Aoi Matsugishi ◽

Yumi Matsuda ◽

...

Keyword(s):

Bone Resorption ◽

Inflammatory Cytokine ◽

Cytokine Production ◽

Alveolar Bone ◽

Inflammatory Cytokine Production

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OCLI-023, a Novel Pyrimidine Compound, Suppresses Osteoclastogenesis In Vitro and Alveolar Bone Resorption In Vivo

PLoS ONE ◽

10.1371/journal.pone.0170159 ◽

2017 ◽

Vol 12 (1) ◽

pp. e0170159 ◽

Cited By ~ 11

Author(s):

Hye Jung Ihn ◽

Taeho Lee ◽

Ju Ang Kim ◽

Doohyun Lee ◽

Nam Doo Kim ◽

...

Keyword(s):

Bone Resorption ◽

Alveolar Bone

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Structural Dissection andIn VivoEffectiveness of a Peptide Inhibitor ofPorphyromonas gingivalisAdherence toStreptococcus gordonii

Infection and Immunity ◽

10.1128/iai.00361-10 ◽

2010 ◽

Vol 79 (1) ◽

pp. 67-74 ◽

Cited By ~ 73

Author(s):

Carlo Amorin Daep ◽

Elizabeth A. Novak ◽

Richard J. Lamont ◽

Donald R. Demuth

Keyword(s):

Bone Resorption ◽

Bone Loss ◽

Alveolar Bone ◽

Alveolar Bone Loss ◽

Peptide Inhibitor ◽

Dental Biofilm ◽

Streptococcal Antigen ◽

Α Helix

ABSTRACTThe interaction of the minor fimbrial antigen (Mfa) with streptococcal antigen I/II (e.g., SspB) facilitates colonization of the dental biofilm byPorphyromonas gingivalis.We previously showed that a 27-mer peptide derived from SspB (designated BAR) resembles the nuclear receptor (NR) box protein-protein interacting domain and potently inhibits this interactionin vitro. Here, we show that the EXXP motif upstream of the NR core α-helix contributes to the Mfa-SspB interaction and that BAR reducesP. gingivaliscolonization and alveolar bone lossin vivoin a murine model of periodontitis. Substitution of Gln for Pro1171or Glu1168increased the α-helicity of BAR and reduced its inhibitory activityin vitroby 10-fold and 2-fold, respectively. To determine if BAR preventsP. gingivalisinfectionin vivo, mice were first infected withStreptococcus gordoniiand then challenged withP. gingivalisin the absence and presence of BAR. Animals that were infected with either 109CFU ofS. gordoniiDL-1 or 107CFU ofP. gingivalis33277 did not show a statistically significant increase in alveolar bone resorption over sham-infected controls. However, infection with 109CFU ofS. gordoniifollowed by 107CFU ofP. gingivalisinduced significantly greater bone loss (P< 0.01) than sham infection or infection of mice with either organism alone.S. gordonii-infected mice that were subsequently challenged with 107CFU ofP. gingivalisin the presence of BAR exhibited levels of bone resorption similar to those of sham-infected animals. Together, these results indicate that both EXXP and the NR box are important for the Mfa-SspB interaction and that BAR peptide represents a potential therapeutic that may limit colonization of the oral cavity byP. gingivalis.

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Deferoxamine Reduces Inflammation and Osteoclastogenesis in Avulsed Teeth

International Journal of Molecular Sciences ◽

10.3390/ijms22158225 ◽

2021 ◽

Vol 22 (15) ◽

pp. 8225

Author(s):

Ko Eun Lee ◽

Mijeong Jeon ◽

Seunghan Mo ◽

Hyo-Seol Lee ◽

Je Seon Song ◽

...

Keyword(s):

Bone Resorption ◽

Alveolar Bone ◽

Root Surface ◽

Tartrate Resistant Acid Phosphatase ◽

Micro Ct ◽

Sprague Dawley ◽

Micro Computed Tomography ◽

Model Cell

Replacement and inflammatory resorption are serious complications associated with the delayed replantation of avulsed teeth. In this study, we aimed to assess whether deferoxamine (DFO) can suppress inflammation and osteoclastogenesis in vitro and attenuate inflammation and bone resorption in a replanted rat tooth model. Cell viability and inflammation were evaluated in RAW264.7 cells. Osteoclastogenesis was confirmed by tartrate-resistant acid phosphatase staining, reactive oxygen species (ROS) measurement, and quantitative reverse transcriptase–polymerase chain reaction in teeth exposed to different concentrations of DFO. In vivo, molars of 31 six-week-old male Sprague–Dawley rats were extracted and stored in saline (n = 10) or DFO solution (n = 21) before replantation. Micro-computed tomography (micro-CT) imaging and histological analysis were performed to evaluate inflammation and root and alveolar bone resorption. DFO downregulated the genes related to inflammation and osteoclastogenesis. DFO also reduced ROS production and regulated specific pathways. Furthermore, the results of the micro-CT and histological analyses provided evidence of the decrease in inflammation and hard tissue resorption in the DFO group. Overall, these results suggest that DFO reduces inflammation and osteoclastogenesis in a tooth replantation model, and thus, it has to be further investigated as a root surface treatment option for an avulsed tooth.

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Beta-Cryptoxanthin Inhibits Lipopolysaccharide-Induced Osteoclast Differentiation and Bone Resorption via the Suppression of Inhibitor of NF-κB Kinase Activity

Nutrients ◽

10.3390/nu11020368 ◽

2019 ◽

Vol 11 (2) ◽

pp. 368 ◽

Cited By ~ 5

Author(s):

Narumi Hirata ◽

Ryota Ichimaru ◽

Tsukasa Tominari ◽

Chiho Matsumoto ◽

Kenta Watanabe ◽

...

Keyword(s):

Bone Resorption ◽

Molecular Mechanism ◽

Transcriptional Activation ◽

Alveolar Bone ◽

Biological Activities ◽

Osteoclast Differentiation ◽

Docking Simulation ◽

Vitro Assay

Beta-cryptoxanthin (β-cry) is a typical carotenoid found abundantly in fruit and vegetables such as the Japanese mandarin orange, persimmon, papaya, paprika, and carrot, and exerts various biological activities (e.g., antioxidant effects). We previously reported that β-cry suppressed lipopolysaccharide (LPS)-induced osteoclast differentiation via the inhibition of prostaglandin (PG) E2 production in gingival fibroblasts and restored the alveolar bone loss in a mouse model for periodontitis in vivo. In this study, we investigated the molecular mechanism underlying the inhibitory effects of β-cry on osteoclast differentiation. In mouse calvarial organ cultures, LPS-induced bone resorption was suppressed by β-cry. In osteoblasts, β-cry inhibited PGE2 production via the downregulation of the LPS-induced mRNA expression of cyclooxygenase (COX)-2 and membrane-bound PGE synthase (mPGES)-1, which are PGE synthesis-related enzymes, leading to the suppression of receptor activator of NF-κB ligand (RANKL) mRNA transcriptional activation. In an in vitro assay, β-cry directly suppressed the activity of the inhibitor of NF-κB kinase (IKK) β, and adding ATP canceled this IKKβ inhibition. Molecular docking simulation further suggested that β-cry binds to the ATP-binding pocket of IKKβ. In Raw264.7 cells, β-cry suppressed RANKL-mediated osteoclastogenesis. The molecular mechanism underlying the involvement of β-cry in LPS-induced bone resorption may involve the ATP-competing inhibition of IKK activity, resulting in the suppression of NF-κB signaling.

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