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Alteration of Homeostasis in Pre-osteoclasts Induced by Aggregatibacter actinomycetemcomitans CDT.

Kawamoto D, Ando-Suguimoto ES, Bueno-Silva B, DiRienzo JM, Mayer MP - Front Cell Infect Microbiol (2016)

Bottom Line: This increase was also observed for TRAP(+) cells with ≥3nuclei, although this difference was not significant.After interaction with AaCDT, transcription of the rank (encoding the receptor RANK), nfatc1 (transcription factor), and ctpK (encoding cathepsin K) genes was downregulated in pre-osteoclastic cells.Therefore, the CDT may impair host defense mechanisms in periodontitis.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo São Paulo, Brazil.

ABSTRACT
The dysbiotic microbiota associated with aggressive periodontitis includes Aggregatibacter actinomycetemcomitans, the only oral species known to produce a cytolethal distending toxin (AaCDT). Give that CDT alters the cytokine profile in monocytic cells, we aimed to test the hypothesis that CDT plays a role in bone homeostasis by affecting the differentiation of precursor cells into osteoclasts. Recombinant AaCDT was added to murine bone marrow monocytes (BMMC) in the presence or absence of RANKL and the cell viability and cytokine profile of osteoclast precursor cells were determined. Multinucleated TRAP(+) cell numbers, and relative transcription of genes related to osteoclastogenesis were also evaluated. The addition of AaCDT did not lead to loss in cell viability but promoted an increase in the average number of TRAP(+) cells with 1-2 nuclei in the absence or presence of RANKL (Tukey, p < 0.05). This increase was also observed for TRAP(+) cells with ≥3nuclei, although this difference was not significant. Levels of TGF-β, TNF-α, and IL-6, in the supernatant fraction of cells, were higher when in AaCDT exposed cells, whereas levels of IL-1β and IL-10 were lower than controls under the same conditions. After interaction with AaCDT, transcription of the rank (encoding the receptor RANK), nfatc1 (transcription factor), and ctpK (encoding cathepsin K) genes was downregulated in pre-osteoclastic cells. The data indicated that despite the presence of RANKL and M-CSF, AaCDT may inhibit osteoclast differentiation by altering cytokine profiles and repressing transcription of genes involved in osteoclastogenesis. Therefore, the CDT may impair host defense mechanisms in periodontitis.

No MeSH data available.


Related in: MedlinePlus

Cytokines levels (TGF-β, IL-1β, TNF-α, and IL-6) in cell supernatant of BMMC added with AaCDT (12.5 and 25.0 μg/ml) after 6 days of incubation, in the absence (A) and presence (B) of 50 ng/ml RANKL. Controls consisted of cells without AaCDT): (0) negative control; (OPG) cells added with 100 ng/ml osteoprotegerin; (100 ng/ml RANKL) cells added with optimal RANKL concentration for osteoclastogenesis. Statistically significant difference (ANOVA-Tukey) when compared with negative control: *p < 0.05, **p < 0.01 and ***p < 0.001.
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Figure 3: Cytokines levels (TGF-β, IL-1β, TNF-α, and IL-6) in cell supernatant of BMMC added with AaCDT (12.5 and 25.0 μg/ml) after 6 days of incubation, in the absence (A) and presence (B) of 50 ng/ml RANKL. Controls consisted of cells without AaCDT): (0) negative control; (OPG) cells added with 100 ng/ml osteoprotegerin; (100 ng/ml RANKL) cells added with optimal RANKL concentration for osteoclastogenesis. Statistically significant difference (ANOVA-Tukey) when compared with negative control: *p < 0.05, **p < 0.01 and ***p < 0.001.

Mentions: After 6 days of incubation of monocyte with 12.5 or 25.0 μg/ml of AaCDT in absence of RANKL (Figure 3A) and addition of RANKL (Figure 3B), resulted in increased production of TGF-β and decreased production of IL-1β in the cultures without RANKL, but in the presence of RANKL, AaCDT exerted no effect on cytokines levels.


Alteration of Homeostasis in Pre-osteoclasts Induced by Aggregatibacter actinomycetemcomitans CDT.

Kawamoto D, Ando-Suguimoto ES, Bueno-Silva B, DiRienzo JM, Mayer MP - Front Cell Infect Microbiol (2016)

Cytokines levels (TGF-β, IL-1β, TNF-α, and IL-6) in cell supernatant of BMMC added with AaCDT (12.5 and 25.0 μg/ml) after 6 days of incubation, in the absence (A) and presence (B) of 50 ng/ml RANKL. Controls consisted of cells without AaCDT): (0) negative control; (OPG) cells added with 100 ng/ml osteoprotegerin; (100 ng/ml RANKL) cells added with optimal RANKL concentration for osteoclastogenesis. Statistically significant difference (ANOVA-Tukey) when compared with negative control: *p < 0.05, **p < 0.01 and ***p < 0.001.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4815040&req=5

Figure 3: Cytokines levels (TGF-β, IL-1β, TNF-α, and IL-6) in cell supernatant of BMMC added with AaCDT (12.5 and 25.0 μg/ml) after 6 days of incubation, in the absence (A) and presence (B) of 50 ng/ml RANKL. Controls consisted of cells without AaCDT): (0) negative control; (OPG) cells added with 100 ng/ml osteoprotegerin; (100 ng/ml RANKL) cells added with optimal RANKL concentration for osteoclastogenesis. Statistically significant difference (ANOVA-Tukey) when compared with negative control: *p < 0.05, **p < 0.01 and ***p < 0.001.
Mentions: After 6 days of incubation of monocyte with 12.5 or 25.0 μg/ml of AaCDT in absence of RANKL (Figure 3A) and addition of RANKL (Figure 3B), resulted in increased production of TGF-β and decreased production of IL-1β in the cultures without RANKL, but in the presence of RANKL, AaCDT exerted no effect on cytokines levels.

Bottom Line: This increase was also observed for TRAP(+) cells with ≥3nuclei, although this difference was not significant.After interaction with AaCDT, transcription of the rank (encoding the receptor RANK), nfatc1 (transcription factor), and ctpK (encoding cathepsin K) genes was downregulated in pre-osteoclastic cells.Therefore, the CDT may impair host defense mechanisms in periodontitis.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology, Institute of Biomedical Sciences, University of São Paulo São Paulo, Brazil.

ABSTRACT
The dysbiotic microbiota associated with aggressive periodontitis includes Aggregatibacter actinomycetemcomitans, the only oral species known to produce a cytolethal distending toxin (AaCDT). Give that CDT alters the cytokine profile in monocytic cells, we aimed to test the hypothesis that CDT plays a role in bone homeostasis by affecting the differentiation of precursor cells into osteoclasts. Recombinant AaCDT was added to murine bone marrow monocytes (BMMC) in the presence or absence of RANKL and the cell viability and cytokine profile of osteoclast precursor cells were determined. Multinucleated TRAP(+) cell numbers, and relative transcription of genes related to osteoclastogenesis were also evaluated. The addition of AaCDT did not lead to loss in cell viability but promoted an increase in the average number of TRAP(+) cells with 1-2 nuclei in the absence or presence of RANKL (Tukey, p < 0.05). This increase was also observed for TRAP(+) cells with ≥3nuclei, although this difference was not significant. Levels of TGF-β, TNF-α, and IL-6, in the supernatant fraction of cells, were higher when in AaCDT exposed cells, whereas levels of IL-1β and IL-10 were lower than controls under the same conditions. After interaction with AaCDT, transcription of the rank (encoding the receptor RANK), nfatc1 (transcription factor), and ctpK (encoding cathepsin K) genes was downregulated in pre-osteoclastic cells. The data indicated that despite the presence of RANKL and M-CSF, AaCDT may inhibit osteoclast differentiation by altering cytokine profiles and repressing transcription of genes involved in osteoclastogenesis. Therefore, the CDT may impair host defense mechanisms in periodontitis.

No MeSH data available.


Related in: MedlinePlus