title: Keratinocyte growth factor stimulates CLC-2 expression in primary fetal rat distal lung epithelial cells.
abstract: Keratinocyte growth factor (KGF) is mitogenic for epithelial cells and induces cystic dilation of fetal lung explants through cystic fibrosis transmembrane conductance regulator-independent chloride channels. One candidate fetal lung chloride channel that is highly expressed on the apical surface of the respiratory epithelium and markedly downregulated after birth is CLC-2. We hypothesized that KGF regulates CLC-2 expression in the fetal lung. Primary fetal rat distal lung epithelial cell monolayers were grown in medium containing 10 ng/ml KGF for 48 h. CLC-2 protein was increased by Western blot analysis of whole-cell lysates in KGF-treated cultures. Similarly, KGF stimulated CLC-2 messenger RNA (mRNA) by Northern blot analysis. This enhanced expression was dose-dependent and maximal at 48 h with 10 ng/ml KGF. Promoter-reporter gene experiments demonstrated that KGF did not stimulate gene transcription. By inhibition of new mRNA synthesis with actinomycin D, evidence was obtained that KGF stabilizes CLC-2 mRNA. We speculate that KGF may positively influence pulmonary chloride and fluid secretion by a secondary pathway affecting CLC-2 degradation.
authors: Department of Pediatrics, Eudowood Division of Respiratory Sciences, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA. cblais@jhmi.edu
authors: C J
authors: CJ
authors: Blaisdell
authors: J P
authors: JP
authors: Pellettieri
authors: C E
authors: CE
authors: Loughlin
authors: S
authors: S
authors: Chu
authors: P L
authors: PL
authors: Zeitlin
mesh_terms: D000818:Animals; D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels / Q000096:biosynthesis / Q000235:genetics*; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects / Q000276:immunology*; D005333:Fetus; D051526:Fibroblast Growth Factor 10; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors; D005786:Gene Expression Regulation; D005865:Gestational Age; D006133:Growth Substances / Q000494:pharmacology; D008168:Lung / Q000166:cytology / Q000276:immunology*; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000096:biosynthesis; D014162:Transfection
chemical_list: D000090007:CLC-2 Chloride Channels; D018118:Chloride Channels; C496455:Fgf7 protein, rat; D051526:Fibroblast Growth Factor 10; D006133:Growth Substances; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D011994:Recombinant Proteins; D051523:Fibroblast Growth Factor 7; D005346:Fibroblast Growth Factors