Am. J. Respir. Cell Mol. Biol., Vol 11, No. 1, 07 1994, 57-65.
Glucocorticoids do not alter peptidase expression on a human bronchial epithelial cell line
D Proud, MC Subauste and PE Ward
Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland.
Respiratory epithelial cell surface neutral endopeptidase 24.11 (NEP-
24.11) degrades proinflammatory peptides, and it has been suggested that
glucocorticoids may reduce airway inflammation, in part, by upregulation of
NEP-24.11. Despite the potential importance of the epithelium as a
metabolic barrier, little is known regarding what other peptidases may be
present on the epithelial cell surface. Using an immortalized bronchial
epithelial cell line (BEAS-2B), we have shown that human epithelial cells
express no detectable angiotensin- converting enzyme, carboxypeptidase N,
or dipeptidyl(amino)peptidase IV, but express significant levels of
aminopeptidase M (AmM), as well as NEP-24.11. The presence of these enzymes
was demonstrated via their degradation of biologically active peptides and
by flow cytometry. Exposure of cells to the glucocorticoid budesonide
(10(-7) M) for up to 5 days did not markedly alter the expression of
NEP-24.11 or AmM, as assessed by flow cytometry, nor did glucocorticoid
treatment modify rates of peptide hydrolysis by NEP-24.11 or AmM. Thus,
BEAS-2B cells have both AmM and NEP-24.11 on their surface, and expression
of these enzymes is not altered by glucocorticoids.
