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Pulm Pharmacol Ther. 2015 Feb;30:110-20. doi: 10.1016/j.pupt.2014.05.007. Epub 2014 Jun 7.

Agonist-induced β2-adrenoceptor desensitization and downregulation enhance pro-inflammatory cytokine release in human bronchial epithelial cells.

Author information

1
Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103 Leipzig, Germany.
2
Department of Paediatric Cardiology, Heart Centre and Translational Centre Regenerative Medicine, University of Leipzig, Leipzig, Germany.
3
Institute of Bacteriology and Mycology, University of Leipzig, Leipzig, Germany.
4
Institute of Pharmacy, University of Leipzig, Leipzig, Germany.
5
Institute of Pharmacology, Pharmacy and Toxicology, University of Leipzig, An den Tierkliniken 15, 04103 Leipzig, Germany. Electronic address: gabraham@rz.uni-leipzig.de.

Abstract

It is not clear whether increased asthma severity associated with long-term use of β2-adrenoceptor (β2-AR) agonists can be attributed to receptor degradation and increased inflammation. We investigated the cross-talk between β-AR agonist-mediated effects on β2-AR function and expression and cytokine release in human bronchial epithelial cells. In 16HBE14o(-) cells grown in the presence and absence of β-AR agonists and/or antagonists, the β2-AR density was assessed by radioligand binding; the receptor protein and mRNA was determined using laser scanning cytometer and RT-PCR; cAMP generation, the cytokines IL-6 and IL-8 release were determined using AlphaScreen Assay and ELISA, respectively. Isoprenaline (ISO) and salbutamol (Salbu) induced a concentration- and time-dependent significant decrease in β2-AR density. Both Salbu and ISO reduced cAMP generation in a concentration-dependent manner while in same cell culture the IL-6 and IL-8 release was significantly enhanced. These effects were antagonized to a greater extent by ICI 118.551 than by propranolol, but CGP 20712A had no effect. Reduction of the β2-AR protein and mRNA could be seen when cells were treated with ISO for 24 h. Our findings indicate a direct link between cytokine release and altered β2-AR expression and function in airway epithelial cells. β2-AR desensitization and downregulation induced by long-term treatment with β2-AR agonists during asthma may account for adverse reactions also due to enhanced release of pro-inflammatory mediators and should, thus, be considered in asthma therapy.

KEYWORDS:

Asthma; Bronchial epithelial cells; cAMP; β(2)-agonists; β-adrenoceptors

PMID:
24915152
DOI:
10.1016/j.pupt.2014.05.007
[Indexed for MEDLINE]

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