Bronchial epithelial cells play a central role in airway remodelling associated with asthma. In this process, a key function is exerted by transforming growth factor-β (TGF-β), whose biological effects are mediated at least in part by mitogen-activated protein kinases (MAPK). Therefore, the main aim of our study was to investigate, in primary cultures of human bronchial epithelial cells (HBEC), the effects of TGF-β on MAPKp38 phosphorylation. In addition, since we have previously shown in human pulmonary endothelial cells that dexamethasone is able to inhibit MAPK activation, a further objective of our research was to verify whether glucocorticoids might interfere with MAPK signalling also in HBEC. After being obtained from fresh surgical specimens, HBEC were grown to confluence and incubated for 2 h with TGF-β1 (10 ng/ml), in the presence or in the absence of a pretreatment with budesonide (10-8 M, for 12 h). Activated p38 was detected by Western blotting, using an anti-phospho-p38 monoclonal antibody that specifically recognizes the phosphorylated, active forms of this MAPK subgroup. TGF-β induced a 5-fold increase in p38 phosphorylation, which was fully prevented by budesonide. Our results provide valuable information about the signal transduction pathways mediating the biological effects of TGF-β in airway epithelium, which represents the first and one of the most important targets of inhaled glucocorticoids such as budesonide. Therefore, the powerful inhibitory effect on p38 phosphorylation-dependent activation, exerted by this drug in bronchial epithelial cells, may significantly contribute to its therapeutic action in asthma.
P38 signalling pathway in primary cultures of human bronchial epithelial cells: effects of transforming growth factor-β and pharmacological modulation by budesonide
VATRELLA, Alessandro;
2002-01-01
Abstract
Bronchial epithelial cells play a central role in airway remodelling associated with asthma. In this process, a key function is exerted by transforming growth factor-β (TGF-β), whose biological effects are mediated at least in part by mitogen-activated protein kinases (MAPK). Therefore, the main aim of our study was to investigate, in primary cultures of human bronchial epithelial cells (HBEC), the effects of TGF-β on MAPKp38 phosphorylation. In addition, since we have previously shown in human pulmonary endothelial cells that dexamethasone is able to inhibit MAPK activation, a further objective of our research was to verify whether glucocorticoids might interfere with MAPK signalling also in HBEC. After being obtained from fresh surgical specimens, HBEC were grown to confluence and incubated for 2 h with TGF-β1 (10 ng/ml), in the presence or in the absence of a pretreatment with budesonide (10-8 M, for 12 h). Activated p38 was detected by Western blotting, using an anti-phospho-p38 monoclonal antibody that specifically recognizes the phosphorylated, active forms of this MAPK subgroup. TGF-β induced a 5-fold increase in p38 phosphorylation, which was fully prevented by budesonide. Our results provide valuable information about the signal transduction pathways mediating the biological effects of TGF-β in airway epithelium, which represents the first and one of the most important targets of inhaled glucocorticoids such as budesonide. Therefore, the powerful inhibitory effect on p38 phosphorylation-dependent activation, exerted by this drug in bronchial epithelial cells, may significantly contribute to its therapeutic action in asthma.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
