Glucocorticoids promote survival of anti-inflammatory macrophages via stimulation of adenosine receptor A3

Blood. 2010 Jul 22;116(3):446-55. doi: 10.1182/blood-2009-10-247106. Epub 2010 May 11.

Abstract

Active resolution of inflammation is a previously unrecognized process essential for tissue homeostasis. Monocytes play a pivotal role in the generation as well as resolution of inflammation. Glucocorticoids (GCs) are widely used anti-inflammatory agents. We demonstrate that GCs exhibit antiapoptotic effects in monocytes resulting in differentiation to an anti-inflammatory phenotype. The molecular basis of this novel antiapoptotic effect is a prolonged activation of the extracellular signal regulated kinase/mitogen-activated protein kinase (ERK/MAPK) pathway resulting in inhibition of caspase activities and expression of antiapoptotic genes via activation of c-Myc. We identified up-regulation and activation of A3 adenosine receptor (A3AR) as the initial trigger of this antiapoptotic pathway. In summary, we deciphered a novel molecular pathway promoting survival of anti-inflammatory monocytes. Specific activation of A3AR or its downstream signaling pathways may thus be a novel strategy to modulate inflammation in autoimmune disorders with fewer side effects via induction of inflammatory resolution rather than immunosuppression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Inflammatory Agents / pharmacology
  • Apoptosis / drug effects
  • Base Sequence
  • Caspases / metabolism
  • Cell Differentiation / drug effects
  • Cell Survival / drug effects
  • Cells, Cultured
  • DNA Primers / genetics
  • Dexamethasone / pharmacology
  • Glucocorticoids / pharmacology*
  • Humans
  • MAP Kinase Signaling System / drug effects
  • Macrophages / cytology
  • Macrophages / drug effects*
  • Macrophages / metabolism*
  • Methylprednisolone / pharmacology
  • Models, Biological
  • Monocytes / cytology
  • Monocytes / drug effects
  • Monocytes / metabolism
  • Receptor, Adenosine A3 / genetics
  • Receptor, Adenosine A3 / metabolism*
  • Staurosporine / pharmacology
  • Triamcinolone / pharmacology
  • Up-Regulation / drug effects

Substances

  • Anti-Inflammatory Agents
  • DNA Primers
  • Glucocorticoids
  • Receptor, Adenosine A3
  • Triamcinolone
  • Dexamethasone
  • Caspases
  • Staurosporine
  • Methylprednisolone