Role of the Cell Wall Microenvironment in Expression of a Heterologous SpaP-S1 Fusion Protein by
            <i>Streptococcus gordonii</i>

Davis, Elisabeth M.; Kennedy, Dustin; Halperin, Scott A.; Lee, Song F.

doi:10.1128/aem.02178-10

Cited by 11 publications

(7 citation statements)

References 48 publications

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“…A possible explanation is that the increased adherence is the result of non-specific interactions between the bacterium and host cell due to a change in cell surface charges. SspA and SspB are calcium-binding proteins (Duan et al, 1994) and in the absence of these two proteins, OB219 has a more negative cell surface charge than the parent strain (Davis et al, 2011). However, the interactions did not involve PAMPs and cellular receptors that lead to cytokine production.…”

Section: Discussionmentioning

confidence: 94%

Role of surface proteins SspA and SspB of Streptococcus gordonii in innate immunity

Andrian

Wang

et al. 2012

Microbiology

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Streptococcus gordonii, a normal inhabitant of the human oral cavity, is a potential live vaccine vehicle. Several pathogen-associated molecular patterns from S. gordonii that are recognized by antigen-presenting cells have recently been identified. In this study, we have identified that the cell-wall-anchored proteins SspA and SspB are immunostimulatory components of S. gordonii. SspA and SspB are members of the antigen I/II family of proteins widely expressed by viridans oral streptococci. The results showed that the mutant (OB219) lacking SspA and SspB had a reduced ability to induce cytokine/chemokine production in epithelial cells and bone-marrow-derived dendritic cells as compared with the parent strain (DL1). Purified SspA induced interleukin-6 and monocyte chemotatic protein-1 production from human lung epithelial A549 cells. The induction could be inhibited by a function-blocking anti-β1 integrin mAb and the purified SspA could bind to β1 integrin precoated on microtitre plates, suggesting that the induction was effected by SspA-β1 integrin interactions. The role of SspA and SspB in innate immunity was further demonstrated in a mouse intranasal challenge experiment, which showed that the clearance of OB219, the recruitment of neutrophils (as indicated by myeloperoxidase activity), and chemokine and cytokine production in the lungs of OB219-inoculated mice were delayed or reduced as compared with the DL1-inoculated mice. In addition to the above, S. gordonii OB219 was more sensitive to polymyxin, nisin and histatin-5 than DL1, suggesting that SspA and SspB also play a role in susceptibility to cationic antimicrobial peptides. Collectively, the results indicate that SspA and SspB are immunostimulatory components of S. gordonii and play an important role in modulating the host's innate immunity.

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Section: Discussionmentioning

confidence: 94%

Role of surface proteins SspA and SspB of Streptococcus gordonii in innate immunity

Andrian

Wang

et al. 2012

Microbiology

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“…In this study, we found that the fluorescence signal of a surface displayed GFP‐SpaP fusion protein was reduced in the S. mutans strain lacking prsA . This result is consistent with observations that there was a positive correlation between the level of PrsA and the amount of a surface‐localized fusion protein consisting of S. mutans SpaP and the pertussis toxin S1 fragment following expression in the heterologous host S. gordonii (Davis et al ., ). Furthermore, the level of PrsA was found to be linearly proportional to the protein secretion rate in B. subtilis (Vitikainen et al ., ); whereas overproduction of PrsA could increase the stability of the amylase and the protective antigen from B. subtilis (Kontinen & Sarvas, ; Williams et al ., ; Vitikaninen et al ., ), and prevent degradation of proteins on the cell surface of L. lactis (Drouault et al ., ).…”

Section: Discussionmentioning

confidence: 97%

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans

Guo

et al. 2012

Molecular Oral Microbiology

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SUMMARY Streptococcus mutans is generally considered to be the principal etiological agent for dental caries. Many of the proteins necessary for its colonization of the oral cavity and pathogenesis are exported to the cell surface or the extracellular matrix, a process that requires the assistance of the export machineries. Bioinformatic analysis revealed that the S. mutans genome contains a prsA gene, whose counterparts in other gram positive bacteria, including Bacillus and Lactococcus encode functions involved in protein post-export. In this study, we constructed a PrsA-deficient derivative of S. mutans and demonstrated that the prsA mutant displayed an altered cell wall/ membrane protein profile as well as cell surface related phenotypes, including auto-aggregation, increased surface hydrophobicity, and abnormal biofilm formation. Further analysis revealed that the disruption of the prsA gene resulted in reduced insoluble glucan production by cell surface localized glucosyltransferases, and mutacin as well as cell surface-display of a heterologous expressed GFP fusion to the cell surface protein SpaP. Our study suggested that PrsA in S. mutans encodes functions similar to the ones identified in Bacillus, and thus is likely involved in protein post-export.

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“…Cells from BHIS cultures with OD 600 values of 0.2 were boiled in SDS-PAGE sample buffer (250 mM Tris-HCl [pH 6.8], 2% sodium dodecyl sulfate, 10% glycerol, 10% 2-mercaptoethanol, 0.01% bromphenol blue), and the protein extracts were electrophoresed on 12.5% SDS-PAGE gels. The proteins were transferred to nitrocellulose membranes (Bio-Rad Laboratories) using standard techniques (34), blocked with 5% skim milk, and reacted with either rabbit anti-HtrA (S. pneumoniae) antiserum (1:500 dilution; a gift from Jeffrey Weiser, University of Pennsylvania) (35) or mouse anti-PrsA antiserum (36). The membranes were then reacted with goat anti-rabbit IgG-alkaline phosphatase (1:30,000 dilution; Sigma-Aldrich) or goat anti-mouse IgG-alkaline phosphatase (1:30,000 dilution; Sigma-Aldrich).…”

Section: Methodsmentioning

confidence: 99%

Mutation of the Thiol-Disulfide Oxidoreductase SdbA Activates the CiaRH Two-Component System, Leading to Bacteriocin Expression Shutdown in Streptococcus gordonii

2016

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Streptococcus gordonii is a commensal inhabitant of the human oral cavity. To maintain its presence as a major component of oral biofilms, S. gordonii secretes inhibitory molecules such as hydrogen peroxide and bacteriocins to inhibit competitors. S. gordonii produces two nonmodified bacteriocins (i.e., Sth 1 and Sth 2 ) that are regulated by the Com two-component regulatory system, which also regulates genetic competence. Previously we found that the thiol-disulfide oxidoreductase SdbA was required for bacteriocin activity; however, the role of SdbA in Com signaling was not clear. Here we demonstrate that ⌬sdbA mutants lacked bacteriocin activity because the bacteriocin gene sthA was strongly repressed and the peptides were not secreted. Addition of synthetic competence-stimulating peptide to the medium reversed the phenotype, indicating that the Com pathway was functional but was not activated in the ⌬sdbA mutant. Repression of bacteriocin production was mediated by the CiaRH two-component system, which was strongly upregulated in the ⌬sdbA mutant, and inactivation of CiaRH restored bacteriocin production. The CiaRH-induced protease DegP was also upregulated in the ⌬sdbA mutant, although it was not required for inhibition of bacteriocin production. This establishes CiaRH as a regulator of Sth bacteriocin activity and links the CiaRH and Com systems in S. gordonii. It also suggests that either SdbA or one of its substrates is an important factor in regulating activation of the CiaRH system. IMPORTANCEStreptococcus gordonii is a noncariogenic colonizer of the human oral cavity. To be competitive in the oral biofilm, S. gordonii secretes antimicrobial peptides called bacteriocins, which inhibit closely related species. Our previous data showed that mutation of the disulfide oxidoreductase SdbA abolished bacteriocin production. In this study, we show that mutation of SdbA generates a signal that upregulates the CiaRH two-component system, which in turn downregulates a second two-component system, Com, which regulates bacteriocin expression. Our data show that these systems are also linked in S. gordonii, and the data reveal that the cell's ability to form disulfide bonds is sensed by the CiaRH system. O ral biofilms are highly competitive, constantly fluctuating environments. The bacteria that colonize this niche contend with a high density of competing bacteria of an estimated 2,000 different taxa and dramatic environmental changes that are dependent on host behavior (1, 2). Streptococcus gordonii is a pioneer colonizer of this environment, where it initiates biofilm formation by binding directly to the acquired salivary pellicle on the tooth surface (2, 3). Once established, S. gordonii persists within the host as part of the oral microbiota. The presence of S. gordonii is associated with oral health (4, 5), and it has been shown to inhibit biofilm formation by cariogenic species (6, 7).S. gordonii uses several strategies to gain advantage over its competitors and to colonize the oral cavity successfully...

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Role of the Cell Wall Microenvironment in Expression of a Heterologous SpaP-S1 Fusion Protein by Streptococcus gordonii

Cited by 11 publications

References 48 publications

Role of surface proteins SspA and SspB of Streptococcus gordonii in innate immunity

Role of surface proteins SspA and SspB of Streptococcus gordonii in innate immunity

Phenotypic characterization of the foldase homologue PrsA in Streptococcus mutans

Mutation of the Thiol-Disulfide Oxidoreductase SdbA Activates the CiaRH Two-Component System, Leading to Bacteriocin Expression Shutdown in Streptococcus gordonii

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