Protein composition of apical surface fluid from the human airway cell line Calu-3: effect of ion transport mediators.
BACKGROUND
Analysis of the protein components of airway secretions is a potential means of detecting and characterizing biochemical alterations associated with airway diseases.


METHODS
We evaluated airway protein secretions using the airway epithelial cell line Calu-3 grown at an air-liquid interface. To observe changes in apically secreted proteins, we analyzed the protein content of apical surface fluid (ASF) washings of Calu-3 monolayers treated with ion transport mediators.


RESULTS
Immunoassay screening for antibacterial and inflammatory proteins indicated the presence of measurable levels of lysozyme and IL-8 in Calu-3 ASF. RT-PCR and immunoassay studies indicated that Calu-3 cells do not produce clara cell 10 kDa protein (CC10). The total protein secretion of Calu-3 was not altered by bradykinin, but amiloride and adenosine significantly increased Calu-3 protein secretion. Lysozyme secretion was not altered by bradykinin, but amiloride and adenosine significantly reduced lysozyme secretion. IL-8 secretion was not altered by bradykinin or adenosine, but amiloride significantly decreased IL-8 secretion.


CONCLUSIONS
Our results demonstrate the presence of antibacterial protein lysozyme and the pro-inflammatory cytokine IL-8 in Calu-3 ASF and that ion transport mediators such as bradykinin, amiloride and adenosine influence the secretion of Calu-3 ASF proteins.
Babu
Polani B Ramesh
PB
Nemours Research Lung Center, Alfred I. duPont Hospital for Children, 1600 Rockland Road, Wilmington, DE 19803, USA. rbabu@nemours.org
Chidekel
Aaron
A
Shaffer
Thomas H
TH
D000241:Adenosine / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D001693:Biological Transport, Active / Q000502:physiology; D015153:Blotting, Western; D001826:Body Fluids / Q000378:metabolism; D001920:Bradykinin / Q000494:pharmacology; D004232:Diuretics / Q000494:pharmacology; D004847:Epithelial Cells / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D007118:Immunoassay; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000737:chemistry; D007477:Ions / Q000378:metabolism; D007781:Lactoferrin / Q000096:biosynthesis; D009113:Muramidase / Q000096:biosynthesis* / Q000737:chemistry; D012333:RNA, Messenger / Q000096:biosynthesis; D012140:Respiratory Tract Diseases / Q000378:metabolism / Q000473:pathology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014665:Vasodilator Agents / Q000494:pharmacology
D004232:Diuretics; D016209:Interleukin-8; D007477:Ions; D012333:RNA, Messenger; D014665:Vasodilator Agents; D000584:Amiloride; D009113:Muramidase; D007781:Lactoferrin; D000241:Adenosine; D001920:Bradykinin