Differentiation of Type II Cells during Explant Culture of Human Fetal Lung Is Accelerated by Endogenous Prostanoids and Adenosine 3′,5′-Monophosphate*

Endocrinology ◽  
1991 ◽  
Vol 128 (6) ◽  
pp. 2916-2924 ◽  
Author(s):  
PHILIP L. BALLARD ◽  
LINDA W. GONZALES ◽  
MARY C. WILLIAMS ◽  
JAMES M. ROBERTS ◽  
MARK M. JACOBS
Keyword(s):  
Fetal Lung ◽  
Explant Culture ◽  
Type Ii Cells ◽  
Type Ii ◽  
Human Fetal Lung

scholarly journals Characterization of the β-Adrenergic Receptor in Isolated Human Fetal Lung Type II Cells

1992 ◽  
Vol 32 (3) ◽  
pp. 350-355 ◽  
Author(s):  
Cynthia K Ewing ◽  
Diane M Duffy ◽  
James M Roberts
Keyword(s):  
Adrenergic Receptor ◽  
Fetal Lung ◽  
Type Ii Cells ◽  
Type Ii ◽  
Human Fetal Lung

A CRE-like element plays an essential role in cAMP regulation of human SP-A2 gene in alveolar type II cells

1996 ◽  
Vol 271 (2) ◽  
pp. L287-L299 ◽  
Author(s):  
P. P. Young ◽  
C. R. Mendelson
Keyword(s):  
Gene Expression ◽  
Lung Tissue ◽  
Fusion Gene ◽  
Fetal Lung ◽  
Inducible Expression ◽  
Nuclear Proteins ◽  
Type Ii Cells ◽  
Type Ii ◽  
Nuclear Extracts ◽  
Human Fetal Lung

The human has two genes encoding surfactant protein-A (SP-A), termed SP-A1 and SP-A2; the SP-A2 gene is more highly regulated by cAMP and during fetal development than is SP-A1. In this study, by use of primary cultures of human type II cells transfected with fusion genes containing various amounts of SP-A2 5'-flanking DNA linked to human growth hormone (hGH) structural gene, as reporter, we found that -296 bp of SP-A2 upstream sequence is sufficient to direct high basal and cAMP-inducible expression in type II cells, but not in other cell types. By use of competitive EMSA, we observed that nuclear proteins isolated from midtrimester human fetal lung tissue bind specifically to a cAMP response element (CRE)-like sequence, TGACCTTA, at -242 bp, which we have termed CRESP-A2. Binding activity of CRESP-A2 for nuclear proteins from human fetal lung tissue before culture was manifest as two complexes of different mobilities and equivalent intensity. By contrast, upon differentiation of the human fetal lung in culture in the presence of dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP), the higher mobility complex was decreased to undetectable levels. By UV cross-linking analysis, using nuclear extracts from midgestation human fetal lung before culture and radiolabeled CRESP-A2 as a probe, we observed binding of proteins of approximately 50, 36, and 30 kDa. When nuclear extracts from human fetal lung cultured in the presence of DBcAMP were analyzed, binding of only the 50- and 36-kDa proteins was apparent. On the other hand, when the canonical CRE (TGACGTCA) known to bind the transcription factor CREB (M(r) approximately 43,000) was used as a probe, binding of only a approximately 43-kDa protein was evident using nuclear extracts from human fetal lung before and after culture. In type II cells transfected with an SP-A2(-296):hGH fusion gene in which CRESP-A2 was mutated, there was a marked reduction of basal and cAMP-stimulated fusion gene expression. These findings indicate that CRESP-A2 serves an important role in mediating basal and cAMP-inducible expression of the human SP-A2 gene in type II cells, that the fetal lung nuclear proteins bound to CRESP-A2 differ from those bound to the canonical palindromic CRE, and that changes in the complex of nuclear proteins bound to CRESP-A2 accompany induction of SP-A gene expression.

Differentiation of type II cells of human fetal lung in vitro

1981 ◽  
Vol 220 (1) ◽  
Author(s):  
JeanneM. Snyder ◽  
JohnM. Johnston ◽  
CaroleR. Mendelson
Keyword(s):  
Fetal Lung ◽  
Type Ii Cells ◽  
Type Ii ◽  
Human Fetal Lung

CEACAM6: A HORMONALLY REGULATED PROTEIN IN DIFFERENTIATING HUMAN FETAL LUNG TYPE II CELLS.

2007 ◽  
Vol 55 (1) ◽  
pp. S97
Author(s):  
P. L. Ballard ◽  
L. W. Gonzales ◽  
V. Kolla ◽  
N. Bailey
Keyword(s):  
Fetal Lung ◽  
Type Ii Cells ◽  
Type Ii ◽  
Human Fetal Lung

Regulation of human pulmonary surfactant protein gene expression by 1α,25-dihydroxyvitamin D3

2005 ◽  
Vol 289 (4) ◽  
pp. L617-L626 ◽  
Author(s):  
Sarabjit S. Phokela ◽  
Sara Peleg ◽  
Fernando R. Moya ◽  
Joseph L. Alcorn
Keyword(s):  
Lung Tissue ◽  
Fetal Lung ◽  
Surfactant Protein ◽  
Type Ii Cells ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Type Ii ◽  
Protein Levels ◽  
Human Fetal Lung ◽  
Dose Dependent

1α,25-Dihydroxyvitamin D3 [1,25(OH)2D3] has been reported to stimulate lung maturity, alveolar type II cell differentiation, and pulmonary surfactant synthesis in rat lung. We hypothesized that 1,25(OH)2D3 stimulates expression of surfactant protein-A (SP-A), SP-B, and SP-C in human fetal lung and type II cells. We found that immunoreactive vitamin D receptor was detectable in fetal lung tissue and type II cells only when incubated with 1,25(OH)2D3. 1,25(OH)2D3 significantly decreased SP-A mRNA in human fetal lung tissue but did not significantly decrease SP-A protein in the tissue. In type II cells, 1,25(OH)2D3 alone had no significant effect on SP-A mRNA or protein levels but reduced SP-A mRNA and protein in a dose-dependent manner when the cells were incubated with cAMP. SP-A mRNA levels in NCI-H441 cells, a nonciliated bronchiolar epithelial (Clara) cell line, were decreased in a dose-dependent manner in the absence or presence of cAMP. 1,25(OH)2D3 had no significant effect on SP-B mRNA levels in lung tissue but increased SP-B mRNA and protein levels in type II cells incubated in the absence or presence of cAMP. Expression of SP-C mRNA was unaffected by 1,25(OH)2D3 in lung tissue incubated ± cAMP. These results suggest that regulation of surfactant protein gene expression in human lung and type II cells by 1,25(OH)2D3 is not coordinated; 1,25(OH)2D3 decreases SP-A mRNA and protein levels in both fetal lung tissue and type II cells, increases SP-B mRNA and protein levels only in type II cells, and has no effect on SP-C mRNA levels.

Prostaglandin E2 integrates the effects of fluid distension and glucocorticoid on lung maturation

1998 ◽  
Vol 274 (1) ◽  
pp. L106-L111 ◽  
Author(s):  
J. S. Torday ◽  
H. Sun ◽  
J. Qin
Keyword(s):  
Fetal Lung ◽  
Explant Culture ◽  
Lung Fibroblasts ◽  
Type Ii Cells ◽  
Type Ii ◽  
Lung Maturation ◽  
Fetal Rat ◽  
Surfactant Production ◽  
Type Ii Cell ◽  
Fetal Lung Maturation

Both glucocorticoids and alveolar fluid distension affect the rate of fetal lung maturation, possibly representing a common cellular pathway. In an explant culture, there is a spontaneous increase in triglyceride incorporation into saturated phosphatidylcholine over time. This mechanism is stimulated by prostaglandin (PG) E2, blocked by both bumetanide and indomethacin, and overridden by exogenous PGE2. Type II cells synthesized and produced PGE2 between days 16 and 21 postconception, increasing fourfold between days 19 and 21. Fetal rat lung fibroblasts released triglyceride in response to PGE2, increasing 10- to 14-fold between days 19 and 21 postconception; phloretin (1 × 10−5 M) completely blocked this effect of PGE2 on triglyceride release. Dexamethasone stimulated both type II cell PGE2 synthesis (threefold) and fibroblast triglyceride release in response to PGE2 (60%) by day 20 cells. Stretching type II cells also increased PGE2 synthesis (∼100% at 1, 2, and 3 h vs. static cultures). Recombination of [3H]triglyceride-labeled fibroblasts with type II cells in an organotypic culture resulted in progressive incorporation of label into saturated phosphatidylcholine by type II cells. This process was also blocked by the addition of indomethacin and overridden by exogenous PGE2. These data suggest that the combined effects of alveolar fluid dilatation and glucocorticoids may coordinate the timely transfer of triglyceride from fibroblasts to type II cells for augmented surfactant production through their effects on PGE2 production and action as term approaches.

Glucocorticoid regulation of epithelial sodium channel genes in human fetal lung

1997 ◽  
Vol 273 (1) ◽  
pp. L227-L233 ◽  
Author(s):  
V. C. Venkatesh ◽  
H. D. Katzberg
Keyword(s):  
Rna Polymerase Ii ◽  
Actinomycin D ◽  
Critical Role ◽  
Fetal Lung ◽  
Explant Culture ◽  
Late Gestation ◽  
Na Channel ◽  
Second Trimester ◽  
Cyclic Monophosphate ◽  
Human Fetal Lung

Pulmonary epithelial Na+ channels (ENaC), composed of three distinct subunits (alpha, beta, and gamma), play a critical role in the regulation of fluid reabsorption from airspaces of late-gestation fetal lung. We studied the expression of ENaC subunit genes in cultured human fetal lung. All three mRNAs were expressed at low levels in second trimester lung (13-32% of adult values at 24 wk gestation). There was a spontaneous increase of approximately threefold over preculture values of all three subunits within 24 h of explant culture in serum-free Waymouth's medium. Dexamethasone (Dex) induced all three mRNAs by two- to threefold. Maximal induction was noted by 8 h with 30-100 nM Dex and half-maximal stimulation with 3-10 nM Dex. Cycloheximide decreased basal expression of all three subunits by 8 h but did not alter the response to Dex. Actinomycin D and 5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole (DRB), inhibitors of RNA polymerase II, decreased the basal and the Dex-induced expression of all three subunits with a more marked effect on human hENaC-gamma than on hENaC-alpha or hENaC-beta. Under conditions where transcription was blocked by actinomycin D or DRB, Dex did not alter the stability of the three mRNAs. Triiodothyronine (T3) at low (2 nM) or high (100 nM) concentrations had no effect on the expression of the three subunits in the presence or absence of low (10 nM) or high (100 nM) concentrations of Dex for 8 or 24 h. Similarly, 8-bromoadenosine 3',5'-cyclic monophosphate (2 microM) had no effect on basal or Dex-induced increase in the three subunits. We conclude that the three Na+ channel subunit genes are expressed in second trimester human fetal lung and are coordinately upregulated by glucocorticoid hormones but not by T3 or adenosine 3',5'-cyclic monophosphate. Glucocorticoid induction is receptor mediated, is primarily transcriptional, and does not require the induction of an intermediate protein for transcriptional enhancement. We speculate that induction of lung ENaC may contribute to the beneficial effects of antenatal glucocorticoids in premature babies.

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