Autocrine ligands for the epidermal growth factor receptor mediate interleukin-8 release from bronchial epithelial cells in response to cigarette smoke.
Airway neutrophilia is a prominent feature of chronic obstructive pulmonary disease. As cigarette smoke (CS) and epidermal growth factor (EGF) both cause release of interleukin-8 (IL-8) from epithelial cells in vitro, we investigated whether autocrine ligands for the EGF receptor (EGFR) are involved in this proinflammatory response to CS. NCI-H292 or primary bronchial epithelial cells were cultured with or without cigarette smoke extract (CSE) or EGF for 6-48 h. We then tested culture supernatants for lactate dehydrogenase activity to assess cell viability, and for IL-8 and EGFR ligands by ELISA; quantitative RT-PCR was used to measure IL-8 and EGFR ligand mRNA. EGF and low concentrations of CSE both promoted cell survival and caused enhanced transcription and release of IL-8. Similarly, levels of mRNA encoding transforming growth factor alpha (TGF-alpha), heparin-binding EGF-like growth factor, and amphiregulin (AR) were increased, as was shedding of TGF-alpha and AR protein into the culture medium. With the exception of AR gene transcription, the CS-induced responses were blocked by the EGFR-selective kinase inhibitor AG1478. Furthermore, ~ 45% of CS-induced IL-8 release was inhibited by a neutralising anti-EGFR. Our data indicate that secretion of IL-8 in response to CSE is dependent on EGFR activation and that autocrine production of TGF-alpha makes a substantial contribution to this response.
Richter
Audrey
A
Respiratory Cell and Molecular Biology Division, School of Medicine, Southampton General Hospital, United Kingdom. aud@soton.ac.uk
O'Donnell
Rory A
RA
Powell
Robert M
RM
Sanders
Michael W
MW
Holgate
Stephen T
ST
Djukanović
Ratko
R
Davies
Donna E
DE
D000328:Adult; D066258:Amphiregulin; D001980:Bronchi / Q000166:cytology / Q000378:metabolism; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D066255:EGF Family of Proteins; D004815:Epidermal Growth Factor / Q000235:genetics / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8 / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D020545:Respiratory Mucosa / Q000378:metabolism*; D012907:Smoking / Q000378:metabolism*; D014026:Nicotiana / Q000009:adverse effects; D016211:Transforming Growth Factor alpha / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; D006023:Glycoproteins; D006133:Growth Substances; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D016209:Interleukin-8; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors