Genetic dependence of the specific T-cell cytokine response to Porphyromonas gingivalis in mice

Background: Susceptibility to periodontal infections may, in part, be genetically determined. Porphyromonas gingivalis is a major periodontopathogen, and the immune response to this organism requires T-cell help. The aim of the present study was to examine the specific T-cell cytokine responses to P gingivalis outer membrane antigens in a mouse model and their relationship with H-2 haplotype. Methods: BALB/c and DBA/2J (H-2(d)), CBACaH (H-2(k)), and C57BL6 (H-2(b)) mice were immunized with P gingivalis outer membrane antigens weekly for 3 weeks. One week after the final injection, the spleens were removed, and 6 T-cell lines specific for P gingivalis were established for each mouse strain. The percentage of CD4 and CD8 cells in the P gingivalis-specific T-cell lines staining positive for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma, and IL-10 was determined by 2-color flow cytometry. Results: The cytokine profiles of T-cell lines from BALB/c and DBA/2J mice showed no significant differences. Significantly fewer IL4+, IFN-gamma+, and IL-10+ CD4 cells than IL-4+, IFN-gamma+, and IL-10+ CD8 cells, respectively, were demonstrated for both strains. P gingivalis-specific T-cell lines generated from CBACaH mice were similar to those generated from BALB/c and DBA/2J mice; however, the mean percentage of IL4+ CD4 cells in CBACaH mice was lower than the percentage of IFN-gamma+ CD4 cells. Also, the mean percentage of IFN-gamma+ CD4 cells in CBACaH mice was significantly increased compared to DBA/2J mice. Unlike the other 3 strains, T-cell lines established from C57BL6 mice contained similar percentages of cytokine-positive cells, although the percentage of IL-4+ CD4 cells was reduced in comparison to the percentage of CD8 cells. However, comparisons with the other 3 strains demonstrated a higher percentage of IL-4+ CD4 cells than in lines established from the spleens of DBA/2J mice, IFN-gamma+ CD4 cells than in lines established from BALB/c and CBACaH mice, and IL-10+ CD4 cells than in lines established from all 3 other strains. No significant differences in the percentage of positive CD8 cells were demonstrated between lines in the 4 strains of mice. Conclusion: The specific T-cell response to P gingivalis in mice may, in the case of the CD4 response, depend on MHC genes. These findings are consistent with the concept that patient susceptibility is important to the outcome of periodontal infection and may, in part, be genetically determined.

Real-time Polymerase Chain Reaction Quantification of Porphyromonas gingivalis and Tannerella forsythia in Primary Endodontic Infections

Introduction: Porphyromonas gingivalis and Tannerella forsythia are anaerobic bacteria commonly involved in root canal infections. Although previous investigations have assessed these species by strictly qualitative approaches, accurate determination of their cell levels by a sensitive quantitative technique may contribute with additional information regarding relevance in pain of endodontic origin. Method: The root canal levels of P gingivalis, T forsythia, and total bacteria were investigated by a quantitative polymerase chain reaction (PCR) assay based on unique copy molecular markers. A total of 32 symptomatic (n = 14) and asymptomatic (n = 18) cases of endodontic infections were analyzed. Root canal samples were collected; genomic DNA was extracted and submitted to SYBR Green I real-time PCR targeting the rgpB (P gingivalis), bspA (T forsythia), and rpoB (total bacteria) single copy genes. Results: Overall, R gingivalis, T forsythia, and the coexistence of both species were encountered in 28%, 66%, and 22% of the subjects, respectively. P gingivalis and T forsythia levels ranged from 5.65 x 10(-6) to 1.20 x 10(-2) and from 5.76 x 10(-6) to 1.35 x 10(-1). T forsythia was highly prevalent and numerous in the study groups, whereas P gingivalis was moderately frequent and less abundant, displaying 19-fold lower average levels than the former. Conclusions: The endodontic levels of P gingivalis and T forsythia, individually or in conjunction, did not display significant associations with the manifestation of pain of endodontic origin. (J Endod 2009,35:1518-1524)

Characterization of serum antibodies to Porphyromonas gingivalis in individuals with and without periodontitis

Although Porphyromonas gingivalis is a defined pathogen in periodontal disease, many subjects control the infection without experiencing loss of attachment. Differences in host susceptibility to the disease may be reflected in the pattern of humoral antibodies against specific P. gingivalis antigens. The aim of this study was to determine the presence of antibodies against immunodominant P. gingivalis antigens as well as the isotype and subclass of anti-P. gingivalis antibodies against outer membrane antigens in four groups of patients: P. gingivalis-positive, 1) with and 2) without periodontitis, and P. gingivalis-negative, 3) with and 4) without periodontitis. Antigens of molecular weight 92, 63, and 32 kDa and lipopolysaccharide were found to be immunodominant. Group 1 subjects showed a significantly higher response to the 92 and 63 kDa antigens compared with other groups. The response to lipopolysaccharide was significantly higher in group 1, and lower in group 4 than in groups 2, 3. Immunoglobulin G(1) (IgG(1)), IgG(2) and IgM antibodies against P. gingivalis outer membrane were present in all subjects, while only some subjects were seropositive for IgG(3), IgG(4) and IgA. There were no differences in concentrations for IgG(1), IgG(3) and IgM. The IgG(2) concentration in group 4 was significantly higher than in groups 1 and 2, while the IgG(4) concentration in group 4 was significantly lower than in other groups. The frequency of seropositivity for IgG(4) and IgA was lowest in group 4, while IgG; seropositivity was almost exclusively seen in healthy patients iii groups 2, 4. These findings suggest that the presence of IgG(3) may reflect non-susceptibility to the disease, while lack of IgG(4) may be indicative of periodontal health and lack of infection.

Genetic variation in the recognition of Porphyromonas gingivalis antigens in mice

T-cell cytokine profiles, anti Porphyromonas gingivalis antibodies and Western blot analysis of antibody responses were examined in BALB/c, CBA/CaH, C57BL6 and DBA/2J mice immunized intraperitoneally with different doses of P. gingivalis outer membrane antigens, Splenic CD4 and CD8 cells were examined for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma and IL-LD by FAGS analysis and levels of anti-P. gingivalis antibodies in the serum samples determined by enzyme-linked immunosorbent assay. Western blot analysis was performed on the sera from mice immunized with 100 mug of P. gingivalis antigens. The four strains of mice demonstrated varying degrees of T-cell immunity although the T-cell cytokine profiles exhibited by each strain were not affected by different immunizing doses. While BALB/c and DBA/2J mice exhibited responses that peaked at immunizing doses of 100-200 mug of P. gingivalis antigens, CBA/CaH and C57BL6 demonstrated weak T-cell responsiveness compared with control mice. Like the T-cell responses, serum antibody levels were not dose dependent. DBA/23 exhibited the lowest levels of anti-P. gingivalis antibodies followed by BALB/c with CBA/CaH and C57BL6 mice demonstrating the highest levels. Western blot analysis showed that there were differences in reactivity between the strains to a group of 13 antigens ranging in molecular weight from 15 to 43 kDa. Antibody responses to a number of these bands in BALB/c mice were of low density, whereas CBA/CaH and C57BL6 mice demonstrated high-density bands and DBA/2J mice showed medium to high responses. In conclusion, different immunizing doses of P. gingivalis outer membrane antigens had little effect on the T-cell cytokine responses and serum anti-P. gingivalis antibody levels. Western blot analysis, however, indicated that the four strains of mice exhibited different reactivity to some lower-molecular-weight antigens. Future studies are required to determine the significance of these differences, which may affect the outcome of P. gingivalis infection.

Distribution of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis and Prevotella intermedia in an Australian population

Background, aim: The present study describes (i) the natural distribution of the three putative periodontopathogens Porphyromonas gingivalis, Prevotella intermedia and Actinobacillus actinomycetemcomitans in an Australian population and (ii) the relationship between these organisms, pocket depths and supragingival plaque scores. Methods: Subgingival plaque was collected from the shallowest and deepest probing site in each sextant of the dentition. In total, 6030 subgingival plaque samples were collected from 504 subjects. An ELISA utilising pathogen-specific monoclonal antibodies was used to quantitate bacterial numbers. Results:: A. actinomycetemcomitans was the most frequently detected organism (22.8% of subjects) followed by P. gingivalis and P. intermedia (14.7% and 9.5% of subjects respectively). The majority of infected subjects (83%) were colonised by a single species of organism. A. actinomyceteincomitans presence was overrepresented in the youngest age group but under-represented in the older age groups. Conversely, P. gingivalis and P. intermedia presence was under-represented in the youngest age group but over-represented in the older age groups. Differing trends in the distribution of these bacteria were observed between subjects depending upon the site of the infection or whether a single or mixed infection was present; however, these differences did not reach significance. Bacterial presence was strongly associated with pocket depth for both A. actinomyceteincomitans and P. gingivalis. For A. actinomycetemcomitans, the odds of a site containing this bacterium decrease with deeper pockets. In contrast, for P. gingivalis the odds of a site being positive are almost six times greater for pockets >3 ram than for pockets less than or equal to3 nun. These odds increase further to 15.3 for pockets deeper than 5 mm. The odds of a site being P. intermedia positive were marginally greater (1.16) for pockets deeper than 3 mm. Conclusions: This cross-sectional study in a volunteer Australian population, demonstrated recognised periodontal pathogens occur as part of the flora of the subgingival plaque. Prospective longitudinal studies are needed to examine the positive relationship between pocket depth and pathogen presence with periodontal disease initiation and/or progression.

The effects of interleukin-10 depletion in vivo on the immune response to Porphyromonas gingivalis in a murine model

Background: The immune response to Porphyromonas gingivalis in the mouse abscess model is known to be dependent upon CD4 T-cell activation and the regulatory role of cytokines. The role of interleukin-10 (IL-10) in this mouse model was examined in vivo. Methods: One-week-old, female BALB/c mice were divided into 4 groups. Groups 1 and 2 were given intraperitoneal (ip) injections of phosphate buffered saline (PBS) weekly for 5 weeks. Group 3 was given an ip injection of rat immunoglobulin. Group 4 was injected with rat anti-IL-10 antibodies. At week 6, group 1 was sham-immunized with PBS, and groups 2, 3, and 4 were injected with P gingivalis lipopolysaccharide (Pg-LPS) weekly for 2 weeks. One week after the final immunization, delayed-type hypersensitivity (DTH) was assessed by footpad swelling to Pg-LPS. The level of serum antibodies to Pg-LPS and IFN-gamma (IFN-gamma) was determined by enzyme-linked immunosorbent assay. Dorsal abscess formation induced by the injection of viable P gingivalis was examined daily for 30 days. Results: The footpad swelling of the anti-IL-10-treated group (group 4) was significantly higher than that of groups 1 to 3. Similarly, the serum IFN-gamma level in group 4 was much higher than that of the other experimental groups. There was no significant difference in serum IgG antibodies to Pg-LPS in any of the experimental groups. However, the level of IgM antibodies in group 4 mice was significantly lower than that in groups 2 and 3. In addition, serum IgG1 was suppressed in group 4 mice, while IgG2a antibodies were raised. However, there was no difference observed between the levels of IgG2b and IgG3 antibodies in any group of mice. The lesions in sham-immunized mice (group 1) persisted for 30 days, and those in group 2 and 3 were undetected by day 18 and 20, respectively. In sharp contrast, lesions in group 4 had healed completely by day 13. Conclusions: This study has shown that IL-10 depletion in vivo in P gingivalis LPS-induced immune response in mice led to an elevated DTH response, an increase in serum IFN-gamma levels, and raised levels of IgG and IgG2a antibodies. Treatment with anti-IL-10 antibodies resulted in suppressed IgG I and IgM responses and a more rapid healing of abscesses than in non-IL-10-depleted mice. These results suggest that IL-10 depletion in Pg-LPS-induced immune response in mice may lead to a Th1-like immune response and provide strong protection against a subsequent challenge with live P gingivalis in an abscess model.

Effect of Fusobacterium nucleatum on the T and B cell responses to Porphyromonas gingivalis in a mouse model

T cell cytokine profiles and specific serum antibody levels in five groups of BALB/c mice immunized with saline alone, viable Fusobacterium nucleatum ATCC 25586, viable Porphyromonas gingivalis ATCC 33277, F. nucleatum followed by P. gingivalis and P. gingivalis followed by F nucleatum were determined. Splenic CD4 and CD8 cells were examined for intracytoplasmic interleukin (IL)-4, interferon (IFN)-gamma and IL-10 by dual colour flow cytometry and the levels of serum anti-F. nucleatum and anti-P. gingivalis antibodies determined by an ELISA. Both Th1 and Th2 responses were demonstrated by all groups, and while there were slightly lower percentages of cytokine positive T cells in mice injected with F. nucleatum alone compared with the other groups immunized with bacteria., F nucleatum had no effect on the T cell production of cytokines induced by P gingivalis in the two groups immunized with both organisms. However, the percentages of cytokine positive CD8 cells were generally significantly higher than those of the CD4 cells. Mice immunized with F nucleatum alone had high levels of serum anti-E nucleatum antibodies with very low levels of P. gingivalis antibodies, whereas mice injected with P gingivalis alone produced anti-P. gingivalis antibodies predominantly. Although the levels of anti-E nucleatum antibodies in mice injected with E nucleatum followed by P. gingivalis were the same as in mice immunized with F nucleatum alone, antibody levels to P. gingivalis were very low. In contrast, mice injected with P. gingivalis followed by F nucleatum produced equal levels of both anti-P. gingivalis and anti-F nucleatum antibodies, although at lower levels than the other three groups immunized with bacteria, respectively. Anti-Actinobacillus actitiomycetemcomitans, Bacteroides forsythus and Prevotella intermedia serum antibody levels were also determined and found to be negligible. In conclusion, F nucleatum immunization does not affect the splenic T cell cytokine response to P. gingivalis. However, F nucleatum immunization prior to that of P. gingivalis almost completely inhibited the production of anti-P gingivalis antibodies while P. gingivalis injection before F. nucleatum demonstrated a partial inhibitory effect by P. gingivalis on antibody production to F. nucleatum. The significance of these results with respect to human periodontal disease is difficult to determine. However, they may explain in part differing responses to P. gingivalis in different individuals who may or may not have had prior exposure to F. nucleatum. Finally, the results suggested that P. gingivalis and F. nucleatum do not induce the production of cross-reactive antibodies to other oral microorganisms.

The role of CD4(+) cells in vivo on the induction of the immune response to Porphyromonas gingivalis in mice

Background: It has previously been suggested that CD4(+) T cells play a pivotal role in regulating the immune response to periodontal pathogens. The aim of the present study therefore was to determine delayed type hypersensitivity (DTH), spleen cell proliferation, serum and splenic anti-Porphyromonas gingivalis antibody levels, and lesion sizes following challenge with viable P. gingiualis in CD4-depleted BALB/c mice immunized with P. gingiualis outer membrane proteins (OMP). Methods: Four groups of BALB/c mice were used. Groups 1 and 2 were injected intraperitoneally (ip) with saline for 3 consecutive days and then weekly throughout the experiment. Groups 3 and 4 were injected ip with rat immunoglobulin and a monoclonal rat anti-mouse CD4 antibody, respectively. Two days later, group 1 mice were injected ip with saline only, while all the other groups were immunized ip with P. gingiualis OMP weekly for 3 weeks. One week later following the last immunization of OMP, 3 separate experiments were conducted to determine: 1) the DTH response to P. gingiualis OMP by measuring footpad swelling; 2) the levels of antibodies to P. gingiualis in serum samples and spleen cell cultures using an enzyme-linked immunosorbent assay, as well as spleen cell proliferation after stimulation with OMP; and 3) the lesion sizes after a subcutaneous challenge with viable P. gingiualis cells. Results: In CD4(+) T-cell-depleted mice (group 4), the DTH response and antigen-stimulated cell proliferation were significantly suppressed when compared to groups 2 and 3. Similarly, the levels of serum and splenic IgM, IgG, and all IgG subclass antibodies to P. gingiualis OMP were depressed. Delayed healing of P. gingivalis-induced lesions was also observed in the CD4(+) T-cell-depleted group. Conclusions: This study has shown that depletion of CD4(+) T cells prior to immunization with P. gingiualis OMP led to the suppression of both the humoral and cell-mediated immune response to this microorganism and that this was associated with delayed healing. These results suggest that the induction of the immune response to P. gingiualis is a CD4(+) T-cell-dependent mechanism and that CD4(+) T cells are important in the healing process.

Acquisition and loss of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia over a 5-year period: effect of a triclosan/copolymer dentifrice

Objectives: The present study describes the natural history of Porphyromonas gingivalis, Actinobacillus actinomycetemcomitans and Prevotella intermedia over a 5-year period and the effect of a triclosan/copolymer dentifrice on these organisms in a normal adult population. Material and Methods: Subgingival plaque samples were collected from 504 adult volunteers. Probing pocket depths (PPD) and relative attachment levels were measured using an automated probe. Participants were matched for disease status (CPI), plaque index, age and gender, and allocated to receive either a triclosan/copolymer or placebo dentifrice. Re-examination and subgingival plaque sampling was repeated after 1, 2, 3, 4 and 5 years. P. gingivalis, A. actinomycetemcomitans and P. intermedia were detected and quantitated using an enzyme linked immunosorbent assay. Logistic regression and generalised linear modelling were used to analyse the data. Results: This 5-year longitudinal study showed considerable volatility in acquisition and loss (below the level of detection) of all three organisms in this population. Relatively few subjects had these organisms on multiple occasions. While P. gingivalis was related to loss of attachment and to PPD greater than or equal to3.5 mm, there was no relationship between A. actinomycetemcomitans or P. intermedia and disease progression over the 5 years of the study. Smokers with P. gingivalis had more PPD greater than or equal to3.5 mm than smokers without this organism. There was no significant effect of the triclosan dentifrice on P. gingivalis or A. actinomycetemcomitans . Subjects using triclosan were more likely to have P. intermedia than those not using the dentifrice; however this did not translate into these subjects having higher levels of P. intermedia and its presence was uniform showing no signs of increasing over the course of the study. Conclusion: The present 5-year longitudinal study has shown the transient nature of colonisation with P. gingivalis , A. actinomycetemcomitans and P. intermedia in a normal adult population. The use of a triclosan-containing dentifrice did not lead to an overgrowth of these organisms. The clinical effect of the dentifrice would appear to be independent of its antimicrobial properties.

Differences in mouse strain influence leukocyte and immunoglobulin phenotype response to Porphyromonas gingivalis

This study examined the nature of the infiltrating cells in Porphyromonas gingivalis-induced lesions and immunoglobulins in the serum samples of BALB/c (H-2(d)), C57BL6 (H-2(b)), DBA/2J (H-2(d)) and CBA/CaH (H-2(k)) mice. Mice were immunized intraperitoneally with P. gingivalis outer membrane antigens or sham-immunized with phosphate-buffered saline followed by subcutaneous challenge with live organisms 1 week after the final immunization. The resulting skin abscesses were excised 7 days later, cryostat sections cut and an immunoperoxidase method used to detect the presence of CD4(+) and CD8(+) T-cell subsets, CD14(+) macrophages and CD19(+) B cells. Peroxidase positive neutrophils and IgG1- and IgG2a-producing plasma cells were also identified. Anti P. gingivalis IgG1 and IgG2a subclass antibodies were determined in serum obtained by cardiac puncture. Very few CD8(+) T cells and CD19(+) B cells were found in any of the lesions. The percentages of CD4(+) cells, CD14(+) cells and neutrophils were similar in lesions of immunized BALB/c and C57BL6 mice, with a trend towards a higher percentage of CD14(+) cells in sham-immunized mice. The percentage of CD14(+) cells was higher than that of CD4(+) cells in immunized compared with sham-immunized DBA/2J mice. The percentages of CD4(+) and CD14(+) cells predominated in immunized CBA/CaH mice and CD4(+) cells in sham-immunized CBA/CaH mice. The percentage of neutrophils in immunized CBA/CaH mice was significantly lower than that of CD14(+) cells and CD4(+) cells in sham-immunized mice. IgG1(+) plasma cells were more dominant than IgG2a(+) cells in immunized BALB/c, C57BL6 and DBA/2J mice, whereas IgG2a(+) plasma cells were more obvious in sham-immunized mice. IgG2a(+) plasma cells were predominant in immunized and sham-immunized CBA/CaH mice. In the serum, specific anti-P. gingivalis IgG2a antibody levels (Th1 response) were higher than IgG1 levels (Th2 response) in sham-immunized CBA/CaH and DBA/2J mice. In immunized BALB/c mice, IgG2a levels were lower than IgG1 levels, while IgG2a levels were higher in immunized C57BL6 mice. In conclusion, this study has shown differences in the proportion of infiltrating leukocytes and in the subclasses of immunoglobulin produced locally and systemically in response to P. gingivalis in different strains of mice, suggesting a degree of genetic control over the response to P. gingivalis.

Presence of Porphyromonas and Prevotella species in the oral microflora of cattle with periodontitis

Abstratc: Bovine periodontitis is a progressive purulent infectious process associated with the presence of strictly and facultative anaerobic subgingival biofilm and epidemiologically related to soil management in large geographic areas of Brazil. This study aimed to detect species of the genera Porphyromonas and Prevotella, which occurr in periodontal pockets of cattle with lesions deeper than 5mm (n=26) and in gingival sulcus of animals considered periodontally healthy (n=25). Presence of the microorganisms was evaluated by independent-culture medium diagnostic method, using polymerase chain reaction (PCR) with specific primers of Porphyromonas asaccharolytica, P. endodontalis, P. gingivalis, P. gulae, Prevotella buccae, P. intermedia, P. loescheii, P. melaninogenica, P. nigrescens, P. oralis and P. tannerae. The species P. endodontalis (80.7%), P. melaninogenica (73.1%) and P. intermedia (61.5%) were the most predominant in samples of cattle with periodontitis. Regarding non-injured gingival sulcus of cattle, P. endodontalis (40%) and P. loeschei (40%) prevailed. Porphyromonas gingivalis, P. gulae and Prevotella tannerae were not detected in the 51 samples studied. Data evaluation by T test, enabled to verify that ocorrence of Porphyromonas asaccharolytica (p=0.000003), P. endodontalis (p=0.0023), Prevotella buccae (p=0.0017), P. intermedia (p=0.0020), P. melaninogenica (p=0.00006) and P. oralis (p=0.0028) is correlated with bovine periodontitis.

Asociación de la presencia de aggregatibacter actinomycetemcomitans, porphyromonas gingivalis y prevotella intermedia en conjunto con la enfermedad periodontal con embarazo pretermino y producto de bajo peso.

Tesis (Maestría en Ciencias Odontológicas con Orientación en Periodoncia con Implantología) UANL, 2012.

Quantification of Porphyromonas gingivalis and fimA genotypes in smoker chronic periodontitis

Teixeira SRL, Mattarazo F, Feres M, Figueiredo LC, de Faveri M, Simionato MRL, Mayer MPA. Quantification of Porphyromonas gingivalis and fimA genotypes in smoker chronic periodontitis. J Clin Periodontol 2009; 36: 482-487. doi: 10.1111/j.1600-051X.2009.01411.x. Porphyromonas gingivalis fimA genotypes were associated with virulence factors in vitro, but little evidence of an association with disease severity were shown in humans. We aimed to correlate levels of P. gingivalis fimA genotypes II and IV and probing depth in smoker-chronic periodontitis subjects. One hundred and sixty eight subgingival samples of 20 smokers non-treated chronic periodontitis subjects obtained from sites with different probing depths [shallow (<= 3 mm), intermediate (4-6 mm), deep (>= 7 mm)] were analysed by real-time PCR for P. gingivalis and genotypes fimA II and IV. P. gingivalis and fimA IV were detected in all subjects, whereas fimA II was detected in 18 subjects (90%). One hundred and fifty two sites (90.5%) harboured P. gingivalis. Genotypes II and IV were detected in 28% and 69.6% of sites, respectively. The proportions of genotypes II and IV in relation to P. gingivalis levels were similar in shallow, intermediate and deep probing sites (2.4%, 4.6%, 1.4% for genotype II and 15.5%, 17.7%, 11.7% for genotype IV, respectively), indicating that other non-tested genotypes were more abundant. Increased levels of genotype IV were associated with increasing probing depth, but not of genotype II. The data suggested an association between P. gingivalis genotype fimA IV and disease severity in smoker-chronic periodontitis subjects.

Effect of a calcium hydroxide/chlorhexidine paste as intracanal dressing in human primary teeth with necrotic pulp against Porphyromonas gingivalis and Enterococcus faecalis

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Porphyromonas gingivalis-mediated shedding of extracellular matrix metalloproteinase inducer (EMMPRIN) by oral epithelial cells: a potential role in inflammatory periodontal disease

Extracellular matrix metalloproteinase inducer (EMMPRIN) or CD 147 is a transmembrane glycoprotein expressed by various cell types, including oral epithelial cells. Recent studies have brought evidence that EMMPRIN plays a role in periodontitis. In the present study, we investigated the effect of Porphyromonas gingivalis, a major pathogen in chronic periodontitis, on the shedding of membrane-anchored EMMPRIN and on the expression of the EMMPRIN gene by oral epithelial cells. A potential contribution of shed EMMPRIN to the inflammatory process of periodontitis was analyzed by evaluating the effect of recombinant EMMPRIN on cytokine and matrix metalloproteinase (MMP) secretion by human gingival fibroblasts. ELISA and immunofluorescence analyses revealed that P. gingivalis mediated the shedding of epithelial cell-surface EMMPRIN in a dose- and time-dependent manner. Cysteine proteinase (gingipain)-deficient P. gingivalis mutants were used to demonstrate that both Arg- and Lys-gingipain activities are involved in EMMPRIN shedding. Real-time PCR showed that P. gingivalis had no significant effect on the expression of the EMMPRIN gene in epithelial cells. Recombinant EMMPRIN induced the secretion of IL-6 and MMP-3 by gingival fibroblasts, a phenomenon that appears to involve mitogen activated protein kinases. The present study brought to light a new mechanism by which P. gingivalis can promote the inflammatory response during periodontitis. (C) 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.