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Tobacco upregulates P. gingivalis fimbrial proteins which induce TLR2 hyposensitivity.

Bagaitkar J, Demuth DR, Daep CA, Renaud DE, Pierce DL, Scott DA - PLoS ONE (2010)

Bottom Line: We have previously shown that cigarette smoke extract (CSE) represents an environmental stress to which P. gingivalis adapts by altering the expression of several virulence factors - including major and minor fimbrial antigens (FimA and Mfa1, respectively) and capsule - concomitant with a reduced pro-inflammatory potential of intact P. gingivalis.We hypothesized that CSE-regulation of capsule and fimbrial genes is reflected at the ultrastructural and functional levels, alters the nature of host-pathogen interactions, and contributes to the reduced pro- inflammatory potential of smoke exposed P. gingivalis.These studies provide some of the first information to explain, mechanistically, how tobacco smoke changes the P. gingivalis phenotype in a manner likely to promote P. gingivalis colonization and infection while simultaneously reducing the host response to this major mucosal pathogen.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, United States of America.

ABSTRACT

Background: Tobacco smokers are more susceptible to periodontitis than non-smokers but exhibit reduced signs of clinical inflammation. The underlying mechanisms are unknown. We have previously shown that cigarette smoke extract (CSE) represents an environmental stress to which P. gingivalis adapts by altering the expression of several virulence factors - including major and minor fimbrial antigens (FimA and Mfa1, respectively) and capsule - concomitant with a reduced pro-inflammatory potential of intact P. gingivalis.

Methodology/principal findings: We hypothesized that CSE-regulation of capsule and fimbrial genes is reflected at the ultrastructural and functional levels, alters the nature of host-pathogen interactions, and contributes to the reduced pro- inflammatory potential of smoke exposed P. gingivalis. CSE induced ultrastructural alterations were determined by electron microscopy, confirmed by Western blot and physiological consequences studied in open-flow biofilms. Inflammatory profiling of specific CSE-dysregulated proteins, rFimA and rMfa1, was determined by quantifying cytokine induction in primary human innate and OBA-9 cells. CSE up-regulates P. gingivalis FimA at the protein level, suppresses the production of capsular polysaccharides at the ultrastructural level, and creates conditions that promote biofilm formation. We further show that while FimA is recognized by TLR2/6, it has only minimal inflammatory activity in several cell types. Furthermore, FimA stimulation chronically abrogates the pro-inflammatory response to subsequent TLR2 stimulation by other TLR-2-specific agonists (Pam3CSK4, FSL, Mfa1) in an IkappaBalpha- and IRAK-1-dependent manner.

Conclusions/significance: These studies provide some of the first information to explain, mechanistically, how tobacco smoke changes the P. gingivalis phenotype in a manner likely to promote P. gingivalis colonization and infection while simultaneously reducing the host response to this major mucosal pathogen.

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Related in: MedlinePlus

CSE induces phenotypic surface changes in P. gingivalis.(A) Typical Western blot of FimA in lysates of 1×106 P. gingivalis cells sequentially passaged in GAM, GAM-CSE, and then fresh GAM, respectively. (B) Typical relative band intensities establish that FimA expression is increased on CSE-exposure, but that FimA expression reverts to control levels upon sub-culturing P. gingivalis back into fresh GAM. Representative transmission electron images of P. gingivalis grown in GAM (C) or GAM-CSE (D). The black arrow indicates the P. gingivalis capsule, which is greatly reduced in presence of CSE. These CSE-induced phenotypic changes are concomitant with an increased binding of P. gingivalis to the FimA ligand, fibronectin (E) and surface availability of FimA (F).
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pone-0009323-g001: CSE induces phenotypic surface changes in P. gingivalis.(A) Typical Western blot of FimA in lysates of 1×106 P. gingivalis cells sequentially passaged in GAM, GAM-CSE, and then fresh GAM, respectively. (B) Typical relative band intensities establish that FimA expression is increased on CSE-exposure, but that FimA expression reverts to control levels upon sub-culturing P. gingivalis back into fresh GAM. Representative transmission electron images of P. gingivalis grown in GAM (C) or GAM-CSE (D). The black arrow indicates the P. gingivalis capsule, which is greatly reduced in presence of CSE. These CSE-induced phenotypic changes are concomitant with an increased binding of P. gingivalis to the FimA ligand, fibronectin (E) and surface availability of FimA (F).

Mentions: Our previous microarray data indicated that CSE induced the expression of genes key to the synthesis and assembly of FimA (PG2133 and PG2134), concomitant with a suppression of several genes in capsular biosynthesis locus (capK, PG0117, PG0118 and wecC) [14]. We now show that CSE-exposure reversibly increases FimA protein, as shown in Figures 1A and B. Transmission electron micrographs clearly establish that these CSE-regulated transcriptional and translational activities are reflected at the ultrastructural level, as shown in Figures 1C and 1D. Furthermore, CSE-induced FimA is both surface exposed, as assessed by availability to FimA-specific antibodies (Figure 1F), and functional, as assessed by binding to the established FimA ligand, fibronectin [24] (Figure 1E).


Tobacco upregulates P. gingivalis fimbrial proteins which induce TLR2 hyposensitivity.

Bagaitkar J, Demuth DR, Daep CA, Renaud DE, Pierce DL, Scott DA - PLoS ONE (2010)

CSE induces phenotypic surface changes in P. gingivalis.(A) Typical Western blot of FimA in lysates of 1×106 P. gingivalis cells sequentially passaged in GAM, GAM-CSE, and then fresh GAM, respectively. (B) Typical relative band intensities establish that FimA expression is increased on CSE-exposure, but that FimA expression reverts to control levels upon sub-culturing P. gingivalis back into fresh GAM. Representative transmission electron images of P. gingivalis grown in GAM (C) or GAM-CSE (D). The black arrow indicates the P. gingivalis capsule, which is greatly reduced in presence of CSE. These CSE-induced phenotypic changes are concomitant with an increased binding of P. gingivalis to the FimA ligand, fibronectin (E) and surface availability of FimA (F).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2864253&req=5

pone-0009323-g001: CSE induces phenotypic surface changes in P. gingivalis.(A) Typical Western blot of FimA in lysates of 1×106 P. gingivalis cells sequentially passaged in GAM, GAM-CSE, and then fresh GAM, respectively. (B) Typical relative band intensities establish that FimA expression is increased on CSE-exposure, but that FimA expression reverts to control levels upon sub-culturing P. gingivalis back into fresh GAM. Representative transmission electron images of P. gingivalis grown in GAM (C) or GAM-CSE (D). The black arrow indicates the P. gingivalis capsule, which is greatly reduced in presence of CSE. These CSE-induced phenotypic changes are concomitant with an increased binding of P. gingivalis to the FimA ligand, fibronectin (E) and surface availability of FimA (F).
Mentions: Our previous microarray data indicated that CSE induced the expression of genes key to the synthesis and assembly of FimA (PG2133 and PG2134), concomitant with a suppression of several genes in capsular biosynthesis locus (capK, PG0117, PG0118 and wecC) [14]. We now show that CSE-exposure reversibly increases FimA protein, as shown in Figures 1A and B. Transmission electron micrographs clearly establish that these CSE-regulated transcriptional and translational activities are reflected at the ultrastructural level, as shown in Figures 1C and 1D. Furthermore, CSE-induced FimA is both surface exposed, as assessed by availability to FimA-specific antibodies (Figure 1F), and functional, as assessed by binding to the established FimA ligand, fibronectin [24] (Figure 1E).

Bottom Line: We have previously shown that cigarette smoke extract (CSE) represents an environmental stress to which P. gingivalis adapts by altering the expression of several virulence factors - including major and minor fimbrial antigens (FimA and Mfa1, respectively) and capsule - concomitant with a reduced pro-inflammatory potential of intact P. gingivalis.We hypothesized that CSE-regulation of capsule and fimbrial genes is reflected at the ultrastructural and functional levels, alters the nature of host-pathogen interactions, and contributes to the reduced pro- inflammatory potential of smoke exposed P. gingivalis.These studies provide some of the first information to explain, mechanistically, how tobacco smoke changes the P. gingivalis phenotype in a manner likely to promote P. gingivalis colonization and infection while simultaneously reducing the host response to this major mucosal pathogen.

View Article: PubMed Central - PubMed

Affiliation: Department of Microbiology and Immunology, School of Medicine, University of Louisville, Louisville, Kentucky, United States of America.

ABSTRACT

Background: Tobacco smokers are more susceptible to periodontitis than non-smokers but exhibit reduced signs of clinical inflammation. The underlying mechanisms are unknown. We have previously shown that cigarette smoke extract (CSE) represents an environmental stress to which P. gingivalis adapts by altering the expression of several virulence factors - including major and minor fimbrial antigens (FimA and Mfa1, respectively) and capsule - concomitant with a reduced pro-inflammatory potential of intact P. gingivalis.

Methodology/principal findings: We hypothesized that CSE-regulation of capsule and fimbrial genes is reflected at the ultrastructural and functional levels, alters the nature of host-pathogen interactions, and contributes to the reduced pro- inflammatory potential of smoke exposed P. gingivalis. CSE induced ultrastructural alterations were determined by electron microscopy, confirmed by Western blot and physiological consequences studied in open-flow biofilms. Inflammatory profiling of specific CSE-dysregulated proteins, rFimA and rMfa1, was determined by quantifying cytokine induction in primary human innate and OBA-9 cells. CSE up-regulates P. gingivalis FimA at the protein level, suppresses the production of capsular polysaccharides at the ultrastructural level, and creates conditions that promote biofilm formation. We further show that while FimA is recognized by TLR2/6, it has only minimal inflammatory activity in several cell types. Furthermore, FimA stimulation chronically abrogates the pro-inflammatory response to subsequent TLR2 stimulation by other TLR-2-specific agonists (Pam3CSK4, FSL, Mfa1) in an IkappaBalpha- and IRAK-1-dependent manner.

Conclusions/significance: These studies provide some of the first information to explain, mechanistically, how tobacco smoke changes the P. gingivalis phenotype in a manner likely to promote P. gingivalis colonization and infection while simultaneously reducing the host response to this major mucosal pathogen.

Show MeSH
Related in: MedlinePlus