Protection against Chlamydia trachomatis infection in vitro and modulation of inflammatory response in vivo by membrane-bound glycosaminoglycans

Toni Darville*, Saul Yedgar, M. Krimsky, C. W. Andrews, Thomas Jungas, David M. Ojcius

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

3 Scopus citations

Abstract

Glycosaminoglycans (GAG) efficiently inhibit adherence of several strains of Chlamydia trachomatis to cell lines in vitro, but none of the GAG have been able to inhibit infections in vivo. One possible cause for failure of GAG inhibition in vivo is the inability to deliver a sustained concentration of GAG at the mucosal surface. We tested the possibility of enhancing cell protection by increasing the cell-surface concentration of GAG using membrane-anchored GAG (MAG), composed of phosphatidylethanolamine (PE)-linked GAG. These lipid conjugates were originally designed as extracellular phospholipase A 2 (PLA2) inhibitors and exhibit a dual effect: the lipid moiety incorporates into the cell membrane, interfering with the action of PLA2 on cell membranes, and the anchored GAG protects the cell membrane from exogenous inflammatory mediators. We tested the ability of MAG to block chlamydia infection in vitro and in vivo. The MAG blocked infection of epithelial cells in vitro when added to the cells at the same time or before infection, but not if added after the bacteria had already invaded the host cells. One of the MAG led to the production of aberrant Chlamydia vacuoles, suggesting it may inhibit intracellular PLA2 associated with development of the vacuole. Although the MAG did not inhibit vaginal infection of mice, they decreased significantly the level of secretion of the inflammatory cytokines TNF-α and IFN-γ but had no effect on secretion of the neutrophil chemokine, macrophage inflammatory protein-2 (MIP-2). Acute and chronic inflammatory cell infiltrates were not altered by MAG treatment. These findings suggest that lipid conjugation of GAG could be used as a novel approach for increasing cell-surface concentrations of GAG. The inconclusive in vivo results might be due to the physical properties of the tested MAG or an insufficient application protocol, and their improvement might provide the desired inhibitory effects.

Original languageEnglish
Pages (from-to)369-376
Number of pages8
JournalMicrobes and Infection
Volume6
Issue number4
DOIs
StatePublished - 04 2004
Externally publishedYes

Keywords

  • Chlamydia infection
  • Chlamydia trachomatis
  • Inflammatory response
  • Phosphatidylethanolamine-linked glycosaminoglycans

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