Am. J. Respir. Cell Mol. Biol., Vol 14, No. 2, Feb 1996, 161-169.
Cellular expression of ceruloplasmin in baboon and mouse lung during development and inflammation
F Yang, WE Friedrichs, L deGraffenried, DC Herbert, FJ Weaker, BH Bowman and JJ Coalson
Department of Cellular and Structural Biology, University of Texas Health Science Center, San Antonio 78284, USA.
Ceruloplasmin (CP) is an important extracellular antioxidant and free
radical scavenger. Although CP is expressed mainly in the liver, recent
studies have identified the lung as another major site of CP synthesis. The
sites and cell types that are responsible for CP expression in baboon and
mouse lung are described. CP mRNA is detected in primordial bronchial
epithelium in baboon fetuses by 60 days of gestation. At 140 days of
gestation and thereafter, CP mRNA is found in airway epithelium and in the
ductal cells of the submucosal glands. In developing and mature mice, CP
mRNA is present in epithelial cells throughout the airway. In
endotoxin-treated mice, the amount of CP mRNA increases several-fold in
large airways but increases only moderately in small airways. This suggests
that the high concentration of CP in the mucus lining of the upper airway,
which serves to filter harmful substances, is particularly important during
stressful conditions. Endotoxin treatment in mice also results in the
induction of high levels of CP mRNA in a subset of alveolar wall cells. The
data suggest that the airway epithelial cells are the major source of CP in
the lung fluid and support ceruloplasmin's critical role in host defense
against oxidative damage and infection in the lung.
