Modulation of GM-CSF release by enantiomers of β-agonists in human airway smooth muscle

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30 Scopus citations


Background: β2-Adrenergic receptor agonists can reduce the release of GM-CSF by human airway smooth muscle cells (HASMCs). These effects are considered anti-inflammatory and are ascribed to the activity of the (R)-enantiomer within the racemate of the agonist. However, the effect of the (S)-enantiomer on GM-CSF release, once thought to be inert, has not been extensively explored. Objective: We hypothesized that the (S)-enantiomer may counter the effects of the (R)-enantiomer, potentially increasing GM-CSF release. Therefore, the effects of administration of individual and combined enantiomers on GM-CSF release were examined. Methods: Cultured HASMCs were stimulated with IL-1β, TNF-α, and IFN-γ and treated with (R)-enantiomers and (S)-enantiomers of albuterol and formoterol, with and without propranolol and ICI-118,551, and in combination with dexamethasone. GM-CSF in the resulting conditioned media was assessed by ELISA. Results: (R)-enantiomers significantly reduced GM-CSF release by as much as 41% (P < .05), which was reversible with propranolol. In contrast, (S)-enantiomers significantly increased GM-CSF release by as much as 34% (P < .05) over release with no drug, and by 25% to 40% (P < .05) when added with (R)-enantiomers. The decremental effect of dexamethasone was amplified by (R)-enantiomers but inhibited by (S)-enantiomers. Both propranolol and ICI-118,551 alone increased GM-CSF release in a concentration-dependent fashion, similar to (S)-enantiomers. Conclusion: We conclude that GM-CSF release by HASMC is downregulated by (R)-enantiomers and enhanced by (S)-enantiomers. The reversal of (R)-enantiomer and dexamethasone effects by the (S)-enantiomer suggests suppression of their anti-inflammatory effects, perhaps through an antagonistic mechanism similar to propranolol.

Original languageEnglish (US)
Pages (from-to)65-72
Number of pages8
JournalJournal of Allergy and Clinical Immunology
Issue number1
StatePublished - Jul 2005
Externally publishedYes


  • Albuterol
  • Formoterol
  • Inverse agonist
  • Levalbuterol
  • Propranolol
  • Racemic
  • cAMP
  • β-receptors

ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology


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