Abstract
RLE-6TN is a cell line having similar characteristics with those in alveolar type II epithelial cells. However, the development of lamellar bodies, characteristic intracellular structures in type II cells, in RLE-6TN cells is not enough. In this study, RLE-6TN cells were transfected with rat ABCA3 gene using a retroviral vector, and phenotypical changes were examined. The expression of ABCA3 mRNA and protein as well as the number and size of lamellar body-like structures was increased in RLE/ABCA3 compared with RLE/Vector cells. Surprisingly, not only the expression of ABCA3 mRNA but also the expression of other mRNAs such as SP-A and PEPT2, that are highly expressed in type II cells than in type I cells, was increased in RLE/ABCA3 cells. In contrast, the expression of mRNAs that are highly expressed in type I cells was hardly increased by ABCA3 transfection. In addition, albumin uptake activity, that is much higher in type II cells than in type I cells, was also enhanced in RLE/ABCA3 cells. These results suggest that the introduction of a single transporter gene ABCA3 would direct RLE-6TN to more type II-like cells, and RLE/ABCA3 cells may be useful as a novel in-vitro model of alveolar type II epithelial cells.
