AJP - Lung Cellular and Molecular Physiology, Vol 268, Issue 5 818-L825, Copyright © 1995 by American Physiological Society
Oxygen modulates surfactant protein mRNA expression and phospholipid production in human fetal lung in vitro
M. J. Acarregui, J. J. Brown and R. K. Mallampalli
Department of Pediatrics, University of Iowa College of Medicine, Iowa City 52242, USA.
We studied the effect of 20-95% O2 on mRNA levels for the
surfactant-associated proteins (SP)-A, SP-B, and SP-C and [3H]choline
incorporation into total phosphatidylcholine and type II cell-specific
disaturated phosphatidylcholine (DPPC) in human fetal lung in culture. SP-A
mRNA levels were increased by 25 and 39% in lung explants incubated in 70
and 95% O2, respectively, compared with levels in tissues incubated in 20%
O2. SP-B mRNA levels were unaffected by O2, whereas SP-C mRNA levels were
increased by 85, 102, and 115% in atmospheres of 35, 50, and 70% O2,
respectively. [3H]choline incorporation into total phosphatidylcholine and
DPPC were both increased in human fetal lung explants incubated in
increased O2 concentrations compared with tissues incubated in 20% O2.
Tissue levels of adenosine 3',5'-cyclic monophosphate (cAMP)-dependent
protein kinase (PKA) activity were not affected by O2 concentration,
implying that the changes observed in SP mRNA levels and [3H]choline
incorporation may not be mediated through alterations in PKA enzyme
activity. These findings demonstrate that O2 regulates SP mRNA expression
and phospholipid production in human fetal lung in vitro. We speculate that
surfactant composition and possibly function may be regulated by O2 in
human lung.
