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Role of glycolipids in the pathogenesis of Enterococcus faecalis urinary tract infection.

Diederich AK, Wobser D, Spiess M, Sava IG, Huebner J, Sakιnç T - PLoS ONE (2014)

Bottom Line: We also demonstrated that these mutants showed a more than three-fold increased binding to human bladder carcinoma cells line T24 compared to the wild-type strain.Lipoteichoic acid (LTA), wall-teichoic acid (WTA), and glycosaminoglycans (GAGs) were not significantly involved in binding of E. faecalis to the bladder epithelial cell line.Further experiments will be needed to clarify the exact mechanism underlying the adhesion through glycolipids and their cognate receptors.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany.

ABSTRACT

Background: After uropathogenic Escherichia coli (UPEC), Enterococcus faecalis is the second most common pathogen causing urinary tract infections. Monoglucosyl-diacylglycerol (MGlcDAG) and diglucosyl-diacylglycerol (DGlcDAG) are the main glycolipids of the E. faecalis cell membrane. Examination of two mutants in genes bgsB and bgsA (both glycosyltransferases) showed that these genes are involved in cell membrane glycolipid biosynthesis, and that their inactivation leads to loss of glycolipids DGlcDAG (bgsA) or both MGlcDAG and DGlcDAG (bgsB). Here we investigate the function of bgsB and bgsA regarding their role in the pathogenesis in a mouse model of urinary tract infection and in bacterial adhesion to T24 bladder epithelial cells.

Results: In a mouse model of urinary tract infection, we showed that E. faecalis 12030ΔbgsB and E. faecalis 12030ΔbgsA mutants, colonize uroepithelial surfaces more efficiently than wild-type bacteria. We also demonstrated that these mutants showed a more than three-fold increased binding to human bladder carcinoma cells line T24 compared to the wild-type strain. Bacterial binding could be specifically inhibited by purified glycolipids. Lipoteichoic acid (LTA), wall-teichoic acid (WTA), and glycosaminoglycans (GAGs) were not significantly involved in binding of E. faecalis to the bladder epithelial cell line.

Conclusions: Our data show that the deletion of bgsB and bgsA and the absence of the major glycolipid diglucosyl-diacylglycerol increases colonization and binding to uroepithelial cells. We hypothesize that secreted diglucosyl-diacylglycerol blocks host binding sites, thereby preventing bacterial adhesion. Further experiments will be needed to clarify the exact mechanism underlying the adhesion through glycolipids and their cognate receptors.

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Effect of different glycosaminoglycans and their lyases on attachment of E. faecalis 12030 strains to T24 uroepithelial cells.E. faecalis 12030 wild-type (A, white bar), E. faecalis 12030ΔbgsB mutant (B, grey bar) and E. faecalis 12030ΔbgsA mutant (C, black bar) were used. Binding of this strains to the confluent monolayers of uroepithelial cells was investigated in the presence of H/heparin (a, 10–1000 µg/mL concentrations), CSB/chondroitin sulfate (b, 10–1000 µg/mL concentrations), HS/heparin sulfate (c, 10–500 µg/mL concentrations), heparin and chondroitin lyase ABC (d, e, heparin lyase 0.5–2 units/mL and chondroitin lyase ABC 0.5–1 units/mL) were used to digest the GAGs chains for 10 min prior to and 2 h after bacterial infection. In all cases an inhibition of bacterial binding to T24 cells were not possible. Bars represent average ± S.E. Using ANOVA test were no significant differences for all (p>0.05) data.
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pone-0096295-g003: Effect of different glycosaminoglycans and their lyases on attachment of E. faecalis 12030 strains to T24 uroepithelial cells.E. faecalis 12030 wild-type (A, white bar), E. faecalis 12030ΔbgsB mutant (B, grey bar) and E. faecalis 12030ΔbgsA mutant (C, black bar) were used. Binding of this strains to the confluent monolayers of uroepithelial cells was investigated in the presence of H/heparin (a, 10–1000 µg/mL concentrations), CSB/chondroitin sulfate (b, 10–1000 µg/mL concentrations), HS/heparin sulfate (c, 10–500 µg/mL concentrations), heparin and chondroitin lyase ABC (d, e, heparin lyase 0.5–2 units/mL and chondroitin lyase ABC 0.5–1 units/mL) were used to digest the GAGs chains for 10 min prior to and 2 h after bacterial infection. In all cases an inhibition of bacterial binding to T24 cells were not possible. Bars represent average ± S.E. Using ANOVA test were no significant differences for all (p>0.05) data.

Mentions: Previous results demonstrated a role of glycosaminoglycans (GAGs) in adhesion to gastrointestinal epithelial cells [22], [23]. To investigate the role of GAGs in E. faecalis binding to bladder epithelial cells, we used heparin, heparan sulfate, and chondroitin sulfate. As shown in figure 3, no significant inhibition of bacterial binding to T24 cells was observed with any of the GAGs using the wild-type strain (Figure 3 A, a–c) and both glycolipid mutants (Figure 3B and 3C, a–c). Although we did not see an effect with different GAGs, we performed additional experiments using enzymatic digestion of GAGs on target cells. As expected, digestion of GAGs with heparin lyase (Figure 3d) and chondroitin lyase (Figure 3e) did not yield any significant change in binding for all strains.


Role of glycolipids in the pathogenesis of Enterococcus faecalis urinary tract infection.

Diederich AK, Wobser D, Spiess M, Sava IG, Huebner J, Sakιnç T - PLoS ONE (2014)

Effect of different glycosaminoglycans and their lyases on attachment of E. faecalis 12030 strains to T24 uroepithelial cells.E. faecalis 12030 wild-type (A, white bar), E. faecalis 12030ΔbgsB mutant (B, grey bar) and E. faecalis 12030ΔbgsA mutant (C, black bar) were used. Binding of this strains to the confluent monolayers of uroepithelial cells was investigated in the presence of H/heparin (a, 10–1000 µg/mL concentrations), CSB/chondroitin sulfate (b, 10–1000 µg/mL concentrations), HS/heparin sulfate (c, 10–500 µg/mL concentrations), heparin and chondroitin lyase ABC (d, e, heparin lyase 0.5–2 units/mL and chondroitin lyase ABC 0.5–1 units/mL) were used to digest the GAGs chains for 10 min prior to and 2 h after bacterial infection. In all cases an inhibition of bacterial binding to T24 cells were not possible. Bars represent average ± S.E. Using ANOVA test were no significant differences for all (p>0.05) data.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4012979&req=5

pone-0096295-g003: Effect of different glycosaminoglycans and their lyases on attachment of E. faecalis 12030 strains to T24 uroepithelial cells.E. faecalis 12030 wild-type (A, white bar), E. faecalis 12030ΔbgsB mutant (B, grey bar) and E. faecalis 12030ΔbgsA mutant (C, black bar) were used. Binding of this strains to the confluent monolayers of uroepithelial cells was investigated in the presence of H/heparin (a, 10–1000 µg/mL concentrations), CSB/chondroitin sulfate (b, 10–1000 µg/mL concentrations), HS/heparin sulfate (c, 10–500 µg/mL concentrations), heparin and chondroitin lyase ABC (d, e, heparin lyase 0.5–2 units/mL and chondroitin lyase ABC 0.5–1 units/mL) were used to digest the GAGs chains for 10 min prior to and 2 h after bacterial infection. In all cases an inhibition of bacterial binding to T24 cells were not possible. Bars represent average ± S.E. Using ANOVA test were no significant differences for all (p>0.05) data.
Mentions: Previous results demonstrated a role of glycosaminoglycans (GAGs) in adhesion to gastrointestinal epithelial cells [22], [23]. To investigate the role of GAGs in E. faecalis binding to bladder epithelial cells, we used heparin, heparan sulfate, and chondroitin sulfate. As shown in figure 3, no significant inhibition of bacterial binding to T24 cells was observed with any of the GAGs using the wild-type strain (Figure 3 A, a–c) and both glycolipid mutants (Figure 3B and 3C, a–c). Although we did not see an effect with different GAGs, we performed additional experiments using enzymatic digestion of GAGs on target cells. As expected, digestion of GAGs with heparin lyase (Figure 3d) and chondroitin lyase (Figure 3e) did not yield any significant change in binding for all strains.

Bottom Line: We also demonstrated that these mutants showed a more than three-fold increased binding to human bladder carcinoma cells line T24 compared to the wild-type strain.Lipoteichoic acid (LTA), wall-teichoic acid (WTA), and glycosaminoglycans (GAGs) were not significantly involved in binding of E. faecalis to the bladder epithelial cell line.Further experiments will be needed to clarify the exact mechanism underlying the adhesion through glycolipids and their cognate receptors.

View Article: PubMed Central - PubMed

Affiliation: Division of Infectious Diseases, University Hospital Freiburg, Freiburg, Germany.

ABSTRACT

Background: After uropathogenic Escherichia coli (UPEC), Enterococcus faecalis is the second most common pathogen causing urinary tract infections. Monoglucosyl-diacylglycerol (MGlcDAG) and diglucosyl-diacylglycerol (DGlcDAG) are the main glycolipids of the E. faecalis cell membrane. Examination of two mutants in genes bgsB and bgsA (both glycosyltransferases) showed that these genes are involved in cell membrane glycolipid biosynthesis, and that their inactivation leads to loss of glycolipids DGlcDAG (bgsA) or both MGlcDAG and DGlcDAG (bgsB). Here we investigate the function of bgsB and bgsA regarding their role in the pathogenesis in a mouse model of urinary tract infection and in bacterial adhesion to T24 bladder epithelial cells.

Results: In a mouse model of urinary tract infection, we showed that E. faecalis 12030ΔbgsB and E. faecalis 12030ΔbgsA mutants, colonize uroepithelial surfaces more efficiently than wild-type bacteria. We also demonstrated that these mutants showed a more than three-fold increased binding to human bladder carcinoma cells line T24 compared to the wild-type strain. Bacterial binding could be specifically inhibited by purified glycolipids. Lipoteichoic acid (LTA), wall-teichoic acid (WTA), and glycosaminoglycans (GAGs) were not significantly involved in binding of E. faecalis to the bladder epithelial cell line.

Conclusions: Our data show that the deletion of bgsB and bgsA and the absence of the major glycolipid diglucosyl-diacylglycerol increases colonization and binding to uroepithelial cells. We hypothesize that secreted diglucosyl-diacylglycerol blocks host binding sites, thereby preventing bacterial adhesion. Further experiments will be needed to clarify the exact mechanism underlying the adhesion through glycolipids and their cognate receptors.

Show MeSH
Related in: MedlinePlus