Expression of TGF-alpha, EGF, and EGF receptor in fetal rat lung.
To define the distribution of transforming growth factor-alpha (TGF-alpha) and its relationship to epidermal growth factor (EGF) and EGF receptor in lung development and to determine whether epithelial cells produce TGF-alpha, we studied the expression of TGF-alpha, EGF, and their receptor in late-gestation fetal rat lung and in cultured fetal rat lung cells. TGF-alpha, EGF, and EGF receptor were colocalized in epithelial and smooth muscle cells of bronchioles and bronchi and in epithelial cells of saccules. Epithelial cells cultured from late-gestation fetal rat lung transcribe TGF-alpha and EGF receptor mRNA and produce TGF-alpha and EGF receptor proteins. Cultured fibroblasts contained EGF receptor mRNA, but no detectable TGF-alpha mRNA. These results demonstrate fetal lung epithelial cells are a source for TGF-alpha and suggest that TGF-alpha might act through an autocrine or paracrine mechanism with epithelial and mesenchymal cells. The colocalization of TGF-alpha and EGF suggests that these growth factors might act in parallel in lung development.
Strandjord
T P
TP
Department of Pediatrics, University of Washington, Fred Hutchinson Cancer Research Center, Seattle 98195.
Clark
J G
JG
Madtes
D K
DK
D000818:Animals; D001483:Base Sequence; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D005333:Fetus / Q000378:metabolism*; D008168:Lung / Q000196:embryology*; D008969:Molecular Sequence Data; D015345:Oligonucleotide Probes / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D014018:Tissue Distribution; D016211:Transforming Growth Factor alpha / Q000378:metabolism*
D015345:Oligonucleotide Probes; D016211:Transforming Growth Factor alpha; D004815:Epidermal Growth Factor; D066246:ErbB Receptors