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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 Proteinase K and sodium meta-periodate treatment of E. faecalis glycolipid mutants and wild-type strain on attachment to T24 uroepithelial cells.The mutants E. faecalis 12030ΔbgsB, E. faecalis 12030Δ bgsA and wild-type strain 12030 were treated with Proteinase K (a, 0.1 mg/mL) and sodium meta periodate (b–d, 0.03125–0.5 mM). Bacteria grown in the same conditions without the proteinase K and sodium-meta periodate were used as controls. There were no significant differences (p>0.05) calculated with ANOVA. Bars represent average ± S.E.
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pone-0096295-g004: Effect of Proteinase K and sodium meta-periodate treatment of E. faecalis glycolipid mutants and wild-type strain on attachment to T24 uroepithelial cells.The mutants E. faecalis 12030ΔbgsB, E. faecalis 12030Δ bgsA and wild-type strain 12030 were treated with Proteinase K (a, 0.1 mg/mL) and sodium meta periodate (b–d, 0.03125–0.5 mM). Bacteria grown in the same conditions without the proteinase K and sodium-meta periodate were used as controls. There were no significant differences (p>0.05) calculated with ANOVA. Bars represent average ± S.E.

Mentions: To determine whether bacterial surface proteins are involved in the binding of mutants to bladder cells, we treated both mutant strains and the wild-type strain with proteinase K (0.1 mg/mL) prior to attachment. After proteolytic treatment neither the glycolipid mutant nor the wild-type strain showed any significant decrease in binding to T24 cells (Figure 4a). Sodium meta-periodate was used to assess the role of bacterial polysaccharides in adhesion. Both glycolipid mutants and wild-type strain were treated with different concentrations of sodium meta-periodate (0.03–0.5 mM) before they were incubated with T24 cells, and no obvious difference in bacterial binding was detected (Figure 4b–d).


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 Proteinase K and sodium meta-periodate treatment of E. faecalis glycolipid mutants and wild-type strain on attachment to T24 uroepithelial cells.The mutants E. faecalis 12030ΔbgsB, E. faecalis 12030Δ bgsA and wild-type strain 12030 were treated with Proteinase K (a, 0.1 mg/mL) and sodium meta periodate (b–d, 0.03125–0.5 mM). Bacteria grown in the same conditions without the proteinase K and sodium-meta periodate were used as controls. There were no significant differences (p>0.05) calculated with ANOVA. Bars represent average ± S.E.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0096295-g004: Effect of Proteinase K and sodium meta-periodate treatment of E. faecalis glycolipid mutants and wild-type strain on attachment to T24 uroepithelial cells.The mutants E. faecalis 12030ΔbgsB, E. faecalis 12030Δ bgsA and wild-type strain 12030 were treated with Proteinase K (a, 0.1 mg/mL) and sodium meta periodate (b–d, 0.03125–0.5 mM). Bacteria grown in the same conditions without the proteinase K and sodium-meta periodate were used as controls. There were no significant differences (p>0.05) calculated with ANOVA. Bars represent average ± S.E.
Mentions: To determine whether bacterial surface proteins are involved in the binding of mutants to bladder cells, we treated both mutant strains and the wild-type strain with proteinase K (0.1 mg/mL) prior to attachment. After proteolytic treatment neither the glycolipid mutant nor the wild-type strain showed any significant decrease in binding to T24 cells (Figure 4a). Sodium meta-periodate was used to assess the role of bacterial polysaccharides in adhesion. Both glycolipid mutants and wild-type strain were treated with different concentrations of sodium meta-periodate (0.03–0.5 mM) before they were incubated with T24 cells, and no obvious difference in bacterial binding was detected (Figure 4b–d).

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