Rat lung alveolar type II cell line maintains sodium transport characteristics of primary culture

• Published in: Journal of cellular physiology Vol. 169; no. 1; pp. 78 - 86
• Main Authors: Michaut, Patrick, Planes, Carole, Escoubet, Brigitte, Clement, Annick, Amiel, Claude, Clerici, Christine
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.10.1996
• Subjects: Amiloride - pharmacology; Amino Acid Transport Systems; Amino Acid Transport Systems, Neutral; Animals; Biological Transport; Carrier Proteins - metabolism; Cell Line; Cells, Cultured; Culture Media - pharmacology; Epithelial Cells; Epithelium - metabolism; Membrane Glycoproteins - metabolism; Monosaccharide Transport Proteins - metabolism; Pulmonary Alveoli - cytology; Pulmonary Alveoli - metabolism; Rats; Rats, Sprague-Dawley; Sodium - metabolism; Sodium Channels - drug effects; Sodium Channels - metabolism; Sodium-Glucose Transporter 1; Sodium-Phosphate Cotransporter Proteins; Sodium-Phosphate Cotransporter Proteins, Type II; Sodium-Potassium-Chloride Symporters; Sodium-Potassium-Exchanging ATPase - metabolism; Symporters
• ISSN: 0021-9541; 1097-4652
• DOI: 10.1002/(SICI)1097-4652(199610)169:1<78::AID-JCP8>3.0.CO;2-B

Culture of primary alveolar type II cells has been widely used to investigate the Na+ transport characteristics of alveolar epithelium. However, this model was restricted by early morphological and physiological dedifferentiation in culture. Recently, a cell line has been obtained by transfection of neonatal type II cells with the simian virus SV40 large T antigen gene (SV40‐T2). SV40‐T2 cells have retained proliferative characteristics of the primary type II cells (Clement et al., 1991, Exp. Cell Res., 196:198–205.) In the present study, we have characterized Na+ transport pathways in SV40‐T2 cells. SV40‐T2 cells retained most cardinal properties of the original alveolar epithelial cells. Na+ entry occurred, as in primary cultures, through both Na+‐cotransporters and amiloride‐sensitive Na+ channels. SV40‐T2 cells expressed Na+‐phosphate, Na+‐amino acid and Na+‐K+‐Cl− cotransports which are quantitatively similar to that of primary cultures. The existence of amiloride‐sensitive Na+ channels was supported by molecular and functional data. SV40‐T2 expressed the cloned α‐and γ‐mRNAs for the rat epithelial Na+ channel (rENaC), whereas β subunit was not detected, and 22Na+ influx was significantly inhibited by 10 μM amiloride. Na+, which enters SV40‐T2 cells, is extruded through a Na+, K+‐ATPase: mRNA for α1 and β1 isoforms of Na+, K+‐ATPase were present and Na+, K+‐ATPase activity was evidenced either on intact cells by the presence of a ouabain‐sensitive component of 86Rb+ influx or on cell homogenates by the measurement of ouabain‐inhibitable ATP hydrolysis. These results indicate that SV40‐T2 cell line displays most of the Na+ transport characteristics of well‐differentiated primary cells in the first days of culture. We conclude that the SV40‐T2 cell line provides a model of differentiated alveolar type II cells and may be a powerful tool to study, in vitro, the modulation of Na+ transport in pathophysiological conditions. © 1996 Wiley‐Liss, Inc.