Background: Nontypeable Haemophilus influenzae (NTHi) is one of the most frequently involved pathogens in bacterial exacerbations of chronic obstructive pulmonary disease (COPD). In the airways, the main tissue target of NTHi is represented by bronchial epithelium, where this pathogen can further amplify the inflammatory and structural changes induced by proinflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha). Therefore, the aim of this study was to investigate, in primary cultures of human bronchial epithelial cells, the effects of NTHi on signal transduction pathways, apoptotic events and chemokine production activated by TNF-alpha. Moreover, we also evaluated the effects exerted on such cellular and molecular phenomena by budesonide. Methods: p38 MAPK phosphorylation was analyzed by Western blotting, using an anti-phospho-p38 MAPK monoclonal antibody. Apoptosis was assayed by active caspase-3 expression. Interleukin-8 (IL-8/CXCL8) was detected in cell-free culture supernatants by ELISA. Results: NTHi was able to markedly potentiate the stimulatory actions of TNFalpha on p38 MAPK phosphorylation, caspase-3 expression and IL-8 secretion. All these effects were significantly (P < 0.01) inhibited by budesonide. Conclusions: These results suggest that NTHi and TNF-alpha can synergistically stimulate, via activation of p38 MAPK signalling pathway, airway epithelial cell apoptosis and IL-8 release. Furthermore, budesonide can be very effective in preventing, through inhibition of p38 MAPK phosphorylation, both structural and proinflammatory changes elicited in bronchial epithelium by NTHi and TNF-alpha.
Effects of budesonide on p38 MAPK activation, apoptosis and IL-8 secretion, induced by TNF-alpha and Haemophilus influenzae in human bronchial epithelial cells
VATRELLA, Alessandro;
2010-01-01
Abstract
Background: Nontypeable Haemophilus influenzae (NTHi) is one of the most frequently involved pathogens in bacterial exacerbations of chronic obstructive pulmonary disease (COPD). In the airways, the main tissue target of NTHi is represented by bronchial epithelium, where this pathogen can further amplify the inflammatory and structural changes induced by proinflammatory cytokines such as tumour necrosis factor-alpha (TNF-alpha). Therefore, the aim of this study was to investigate, in primary cultures of human bronchial epithelial cells, the effects of NTHi on signal transduction pathways, apoptotic events and chemokine production activated by TNF-alpha. Moreover, we also evaluated the effects exerted on such cellular and molecular phenomena by budesonide. Methods: p38 MAPK phosphorylation was analyzed by Western blotting, using an anti-phospho-p38 MAPK monoclonal antibody. Apoptosis was assayed by active caspase-3 expression. Interleukin-8 (IL-8/CXCL8) was detected in cell-free culture supernatants by ELISA. Results: NTHi was able to markedly potentiate the stimulatory actions of TNFalpha on p38 MAPK phosphorylation, caspase-3 expression and IL-8 secretion. All these effects were significantly (P < 0.01) inhibited by budesonide. Conclusions: These results suggest that NTHi and TNF-alpha can synergistically stimulate, via activation of p38 MAPK signalling pathway, airway epithelial cell apoptosis and IL-8 release. Furthermore, budesonide can be very effective in preventing, through inhibition of p38 MAPK phosphorylation, both structural and proinflammatory changes elicited in bronchial epithelium by NTHi and TNF-alpha.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
