AJP - Lung Cellular and Molecular Physiology, Vol 259, Issue 4 283-L293, Copyright © 1990 by American Physiological Society
Hormonally regulated proteins in cultured human fetal lung: analysis by two-dimensional gel electrophoresis
M. W. Odom, R. Ertsey and P. L. Ballard
Department of Pediatrics, Mt. Zion Hospital, San Francisco, California.
We used high-resolution two-dimensional polyacrylamide gel electrophoresis
(2-D PAGE) to identify hormonally regulated proteins in cultured human
fetal lung. Proteins labeled with [35S]methionine were separated by 2-D
PAGE, and fluorograms were analyzed by computer-assisted analysis of
densitometric scans. Dexamethasone (10 nM) and gamma-interferon (10 ng/ml)
induced (2- to 22-fold vs. control) distinct sets of proteins (comprising
approximately 2% of approximately 1,000 resolved proteins). Treatment with
forskolin (10 microM) plus 3-isobutyl-1-methylxanthine (IBMX, 100 microM),
which increases intracellular adenosine 3',5'-cyclic monophosphate (cAMP),
induced both unique proteins and several proteins induced by dexamethasone.
One protein (Mr 40,000, pI 4.4) was induced only with combined
dexamethasone and cAMP treatment. Dexamethasone repressed four proteins,
but inhibition was not observed with other hormones. Some of the regulated
proteins were enriched in either fibroblasts or type II cells isolated from
lung explants. We found no proteins that were consistently regulated by
triiodothyronine (T3) (2 nM) or transforming growth factor-beta (10 ng/ml).
Additionally, none of the hormonal treatments substantially altered the
rate of methionine incorporation into total protein. Thus we have
identified separate subsets of proteins that are regulated by
glucocorticoids, gamma-interferon, and cAMP; these proteins may be
important mediators of hormonal effects in the developing fetal lung.
