Fibrosis is part of airway remodelling observed in bronchial asthma and COPD. Pro-fibrotic activity of lung fibroblasts may be suppressed by β-adrenoceptor activation. We aimed, first, to characterise the expression pattern of β-adrenoceptor subtypes in human lung fibroblasts and, second, to probe β-adrenoceptor signalling with an emphasis on anti-fibrotic actions. Using reverse transcription PCR, messenger RNA (mRNA) encoding β 2 -adrenoceptors was detected in MRC-5, HEL-299 and primary human lung fibroblasts, whereas transcripts for β 1 -and β 3 -adrenoceptors were not found. Real-time measurement of dynamic mass redistribution in MRC-5 cells revealed β-agonistinduced G s -signalling. Proliferation of MRC-5 cells (determined by [ 3 H]-thymidine incorporation) was significantly inhibited by β-agonists including the β 2 -selective agonist formoterol (−logIC 50 , 10.2) and olodaterol (−logIC 50 , 10.6). Formoterol's effect was insensitive to β 1 -antagonism (GCP 20712, 3 μM), but sensitive to β 2 -antagonism (ICI 118,551; apparent, pA 2 , 9.6). Collagen synthesis in MRC-5 cells (determined by [ 3 H]-proline incorporation) was inhibited by β-agonists including formoterol (−logIC 50 , 10.0) and olodaterol (−logIC 50 , 10.3) in a β 2 -blockersensitive manner. α-Smooth muscle actin, a marker of myofibroblast differentiation, was down-regulated at the mRNA and the protein level by about 50% following 24 and 48 h exposure to 1 nM formoterol, a maximally active concentration. In conclusion, human lung fibroblasts exclusively express β 2 -adrenoceptors and these mediate inhibition of various markers of pro-fibrotic cellular activity. Under clinical conditions, anti-fibrotic actions may accompany the therapeutic effect of long-term β 2 -agonist treatment of bronchial asthma and COPD.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.