The danger signal adenosine induces persistence of chlamydial infection through stimulation of A2b receptors

PLoS One. 2009 Dec 14;4(12):e8299. doi: 10.1371/journal.pone.0008299.

Abstract

Infections with intracellular bacteria such as chlamydiae affect the majority of the world population. Infected tissue inflammation and granuloma formation help contain the short-term expansion of the invading pathogen, leading also to local tissue damage and hypoxia. However, the effects of key aspects of damaged inflamed tissues and hypoxia on continued infection with intracellular bacteria remain unknown. We find that development of Chlamydia trachomatis is reversibly retarded by prolonged exposure of infected cells to extracellular adenosine, a hallmark of hypoxia and advanced inflammation. In epithelial cells, this effect was mediated by the A2b adenosine receptor, unique in the adenosine receptor family for having a hypoxia-inducible factor (HIF1-alpha) binding site at its promoter region, and was dependent on an increase in the intracellular cAMP levels, but was independent of cAMP-dependent protein kinase (PKA). Further study of adenosine receptor signaling during intracellular bacterial infection could lead to breakthroughs in our understanding of persistent infections with these ubiquitous pathogens.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine / pharmacology*
  • Cell Membrane Permeability / drug effects
  • Chlamydia Infections / metabolism*
  • Chlamydia Infections / microbiology
  • Chlamydia trachomatis / drug effects
  • Chlamydia trachomatis / growth & development
  • Chlamydia trachomatis / ultrastructure
  • Cyclic AMP / analogs & derivatives
  • Cyclic AMP / pharmacology
  • Cyclic AMP-Dependent Protein Kinases / metabolism
  • Extracellular Space / drug effects
  • Extracellular Space / metabolism
  • HeLa Cells
  • Humans
  • Inclusion Bodies / drug effects
  • Inclusion Bodies / ultrastructure
  • Receptor, Adenosine A2B / metabolism*
  • Signal Transduction / drug effects*

Substances

  • Receptor, Adenosine A2B
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Adenosine