Effect of beta2-adrenoceptor agonists and other cAMP-elevating agents on inflammatory gene expression in human ASM cells: a role for protein kinase A

Am J Physiol Lung Cell Mol Physiol. 2008 Sep;295(3):L505-14. doi: 10.1152/ajplung.00046.2008. Epub 2008 Jun 27.

Abstract

In diseases such as asthma, airway smooth muscle (ASM) cells play a synthetic role by secreting inflammatory mediators such as granulocyte-macrophage colony-stimulating factor (GM-CSF), IL-6, or IL-8 and by expressing surface adhesion molecules, including ICAM-1. In the present study, PGE(2), forskolin, and short-acting (salbutamol) and long-acting (salmeterol and formoterol) beta(2)-adrenoceptor agonists reduced the expression of ICAM-1 and the release of GM-CSF evoked by IL-1beta in ASM cells. IL-1beta-induced IL-8 release was also repressed by PGE(2) and forskolin, whereas the beta(2)-adrenoceptor agonists were ineffective. In each case, repression of these inflammatory indexes was prevented by adenoviral overexpression of PKIalpha, a highly selective PKA inhibitor. These data indicate a PKA-dependent mechanism of repression and suggest that agents that elevate intracellular cAMP, and thereby activate PKA, may have a widespread anti-inflammatory effect in ASM cells. Since ICAM-1 and GM-CSF are highly NF-kappaB-dependent genes, we used an adenoviral-delivered NF-kappaB-dependent luciferase reporter to examine the effects of forskolin and the beta(2)-adrenoceptor agonists on NF-kappaB activation. There was no effect on luciferase activity measured in the presence of forskolin or beta(2)-adrenoceptor agonists. This finding is consistent with the observation that IL-1beta-induced expression of IL-6, a known NF-kappaB-dependent gene in ASM, was also unaffected by beta(2)-adrenoceptor agonists, forskolin, PGE(2), 8-bromo-cAMP, or rolipram. Collectively, these results indicate that repression of IL-1beta-induced ICAM-1 expression and GM-CSF release by cAMP-elevating agents, including beta(2)-adrenoceptor agonists, may not occur through a generic effect on NF-kappaB.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-2 Receptor Agonists*
  • Albuterol / analogs & derivatives
  • Albuterol / pharmacology
  • Cells, Cultured
  • Colforsin / pharmacology
  • Cyclic AMP / metabolism*
  • Cyclic AMP-Dependent Protein Kinases / metabolism*
  • Dinoprostone / pharmacology
  • Gene Expression / drug effects
  • Granulocyte-Macrophage Colony-Stimulating Factor / biosynthesis
  • Granulocyte-Macrophage Colony-Stimulating Factor / genetics
  • Humans
  • Inflammation Mediators / metabolism*
  • Intercellular Adhesion Molecule-1 / biosynthesis
  • Intercellular Adhesion Molecule-1 / genetics
  • Interleukin-6 / biosynthesis
  • Interleukin-6 / genetics
  • Interleukin-8 / biosynthesis
  • Interleukin-8 / genetics
  • Myocytes, Smooth Muscle / drug effects*
  • Myocytes, Smooth Muscle / metabolism*
  • Respiratory System / cytology
  • Respiratory System / drug effects*
  • Respiratory System / metabolism*
  • Salmeterol Xinafoate

Substances

  • Adrenergic beta-2 Receptor Agonists
  • CXCL8 protein, human
  • IL6 protein, human
  • Inflammation Mediators
  • Interleukin-6
  • Interleukin-8
  • Intercellular Adhesion Molecule-1
  • Colforsin
  • Salmeterol Xinafoate
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • Cyclic AMP
  • Cyclic AMP-Dependent Protein Kinases
  • Dinoprostone
  • Albuterol