Acetylcholine and nicotine stimulate the release of granulocyte-macrophage colony stimulating factor from cultured human bronchial epithelial cells

Abstract

Primary cultures of human bronchial epithelial cells (HBE-cells) were established to measure granulocyte-macrophage colony stimulating factor (GM-CSF) release. HBE-cells showed a basal GM-CSF release (82±20 ng/well/24 h; 30 donors), which was increased by interleukin-1 β (IL-1β, 1 ng/ml) by 270%. This effect was blocked by 1 μM dactinomycin or 10 μM cycloheximide, i.e. the stimulatory effect of IL-1β depended on de-novo synthesis. Histamine (100 μM) and acetylcholine (100 nM) stimulated GM-CSF release more than two-fold above the baseline. Nicotine (1 μM) increased GM-CSF release to a similar extent, and this effect was prevented by 30 μM (+)-tubocurarine. The stimulatory effect was attenuated or even lost with high agonist concentrations (10 μM acetylcholine; 100 μM nicotine) suggesting receptor desensitization. The muscarinic receptor agonist oxotremorine did not affect GM-CSF release. Serotonin, substance P and calcitonin-gene related peptide had no effect on GM-CSF release. In conclusion, acetylcholine can trigger GM-CSF release from human airway epithelial cells via stimulation of nicotinic receptors.