Production of the acute-phase protein lipopolysaccharide-binding protein by respiratory type II epithelial cells - Implications for local defense to bacterial endotoxins
Ma. Dentener et al., Production of the acute-phase protein lipopolysaccharide-binding protein by respiratory type II epithelial cells - Implications for local defense to bacterial endotoxins, AM J RESP C, 23(2), 2000, pp. 146-153
Citations number
46
Categorie Soggetti
da verificare
Journal title
AMERICAN JOURNAL OF RESPIRATORY CELL AND MOLECULAR BIOLOGY
This study demonstrates for the first time that respiratory epithelial cell
s are able to produce the acute phase protein lipopolysaccharide (LPS)-bind
ing protein (LBP), which is known to play a central role in the defense to
bacterial endotoxins (or LPS). Indications for local presence of LBP in hum
an lung was obtained via reverse transcriptase/polymerase chain reaction th
at showed LBP messenger RNA (mRNA) expression. Therefore, LBP production by
the human lung epithelial cell line A549, a human adenocarcinoma with feat
ures of type II pneumocytes, was studied. These cells produced LBP in respo
nse to interleukin (IL)-1 beta, IL-6, and tumor necrosis factor-alpha, a re
sponse that was strongly enhanced by dexamethasone. In addition, LBP mRNA w
as detected in A549 cells, in increasing amounts as a result of stimulation
. The pattern of cytokine-induced LBP production in A549 cells was similar
to the pattern in the human liver epithelial cell line HuH-7. Moreover, the
molecular weight of A549-derived LBP was approximately 60 kD, which is sim
ilar to HuH-7-derived LBP, Biologic activity of LBP produced by A549 cells
was evaluated on the basis of its ability to interact with LPS. Further ind
ications that type II alveolar epithelial cells are able to produce LBP wer
e obtained from the observations that the murine lung type II epithelial ce
ll line C10 produced murine LBP, and that isolated human primary type II pn
eumocytes expressed LBP mRNA, which was enhanced after stimulation of cells
. The local production of this endotoxin binding protein by lung epithelial
cells might contribute to a highly specific response at the site of exposu
re to bacteria and bacterial endotoxins.