Developmental differences of cystic fibrosis transmembrane conductance regulator functional expression in isolated rat fetal distal airway epithelial cells.
Fluid secretion from the pulmonary epithelium may play a significant role in determining intrauterine lung development. We used suspensions of distal pulmonary epithelial cells isolated from rat fetuses to assess a shift in secretory mechanisms occurring in the lung of this species during late gestation. The impact of cAMP on distal airway epithelial cells isolated from d 18 to d 21 rat fetuses was evaluated with measurements of cell volume and 36Cl efflux rates. At d 18, 8-Br-cAMP stimulated a volume reduction measured by electronic cell sizing that was prevented by the Cl- channel blocker anthracene-9-carboxylate (A-9C) and reflected in an increased rate of A-9C sensitive 36Cl efflux. Because the cystic fibrosis transmembrane conductance regulator (CFTR) is thought to be a cAMP-regulated Cl- channel, we measured the effect of prior cell incubation with oligodeoxynucleotides antisense to the transcription site of the human CFTR gene on these events. We found that in antisense oligomer-treated cells, but not in sense oligomer-treated controls, volume and 36Cl efflux responses to 8-Br-cAMP were prevented in d 18 cells. In d 21 cells, 8-Br-cAMP did not stimulate volume reduction but the calcium ionophore A23187 did elicit cell volume reduction in cells suspended in an isotonic Ca(2+)-containing medium that was prevented by A-9C. This response to the ionophore was not found in the d 18 cells, and incubation with the antisense CFTR oligomer had no effect on the ionophore-induced responses in d 21 cells.(ABSTRACT TRUNCATED AT 250 WORDS)
MacLeod
R J
RJ
McGill University-Montreal Children's Hospital Research Institute, Department of Paediatrics, Quebec, Canada.
Hamilton
J R
JR
Kopelman
H
H
Sweezey
N B
NB
D015124:8-Bromo Cyclic Adenosine Monophosphate / Q000494:pharmacology; D000818:Animals; D001483:Base Sequence; D000001:Calcimycin / Q000494:pharmacology; D048429:Cell Size / Q000187:drug effects; D018118:Chloride Channels / Q000187:drug effects / Q000378:metabolism; D002712:Chlorides / Q000378:metabolism; D003550:Cystic Fibrosis / Q000235:genetics / Q000378:metabolism*; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D005333:Fetus / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D005865:Gestational Age; D066298:In Vitro Techniques; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016376:Oligonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D051381:Rats
D018118:Chloride Channels; D002712:Chlorides; D008565:Membrane Proteins; D016376:Oligonucleotides, Antisense; D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D015124:8-Bromo Cyclic Adenosine Monophosphate; D000001:Calcimycin