title: Glucose transporter gene expression in freshly isolated and cultured rat pneumocytes.
abstract: Alveolar epithelium in situ takes up luminal glucose by cotransport with sodium. Cultured alveolar type II pneumocytes have only sodium-independent glucose uptake. It is unclear which isoforms are responsible for glucose transport in these cells and why sodium-glucose cotransport activity disappears during culture. GLUT1, GLUT4, GLUT5 and SGLT1 mRNA were detected in freshly isolated rat alveolar type II cells by reverse transcriptase-polymerase chain reaction. We show that SGLT1 mRNA was 90% lower in cells cultured in plastic wells for 2 or 4 days than in freshly isolated cells. mRNAs coding for the facilitated transporters were reduced from 40% (GLUT1) and 75% (GLUT4 and GLUT5) in cultured cells. Cells cultured at the air-liquid interface better preserved their phenotype as attested by significantly higher surfactant-associated protein mRNA levels. However, these cells had no higher GLUT1 and SGLT1 gene expression. Thus, alveolar type II cells lose sodium-glucose cotransport activity in part because of a decrease in mRNA levels. These changes in gene expression and/or mRNA stability may be an additional consequence of the shift towards the type I cell phenotype observed in cultured type II pneumocytes.
authors: INSERM U82, Faculté Xavier Bichat, Paris, France.
authors: K
authors: K
authors: Mamchaoui
authors: Y
authors: Y
authors: Makhloufi
authors: G
authors: G
authors: Saumon
mesh_terms: D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002478:Cells, Cultured; D015870:Gene Expression / Q000502:physiology; D005947:Glucose / Q000378:metabolism; D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D008297:Male; D008562:Membrane Glycoproteins / Q000235:genetics; D009004:Monosaccharide Transport Proteins / Q000235:genetics*; D009124:Muscle Proteins; D010641:Phenotype; D011650:Pulmonary Alveoli / Q000166:cytology / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D020545:Respiratory Mucosa / Q000166:cytology / Q000502:physiology; D012964:Sodium / Q000378:metabolism; D051269:Sodium-Glucose Transporter 1
chemical_list: D051272:Glucose Transporter Type 1; D051275:Glucose Transporter Type 4; D051296:Glucose Transporter Type 5; D008562:Membrane Glycoproteins; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; C495679:Slc2a1 protein, rat; C495694:Slc2a4 protein, rat; C495676:Slc5a1 protein, rat; D051269:Sodium-Glucose Transporter 1; D012964:Sodium; D005947:Glucose