RLE-6TN Cells

The RLE-6TN cell line is an immortalized rat alveolar type II epithelial cell line derived from adult Fischer 344 rats. RLE-6TN was established through spontaneous immortalization during attempts to introduce the SV40-T antigen gene into primary alveolar type II epithelial cells. Unlike its counterpart RLE-6T, which was positively transfected with the SV40-T antigen, RLE-6TN cells do not express the T-antigen gene. Despite this, RLE-6TN cells retain critical morphological and functional features characteristic of alveolar type II cells, including cytokeratin expression and the presence of lipid-containing lamellar inclusion bodies.

RLE-6TN cells have been widely used as an in vitro model for investigating lung epithelial cell biology, alveolar function, and responses to various physiological and pathological stimuli. They are particularly relevant for studying Na-K-ATPase regulation and activity in alveolar epithelial cells. Na-K-ATPase is essential for maintaining cellular ion gradients and trans-epithelial ion transport, processes critical for alveolar fluid clearance in the lungs. In studies, thyroid hormone (T3) has been shown to stimulate Na-K-ATPase activity in RLE-6TN cells by enhancing its translocation to the plasma membrane rather than increasing its transcription, highlighting a novel, rapid regulatory mechanism.

RLE-6TN cells demonstrate stable growth, with near-diploid karyotype stability, and are not tumorigenic in nude mice. They are negative for alkaline phosphatase activity but stain positive for cytokeratins 8, 18, and 19, confirming their epithelial origin. RLE-6TN cells can be maintained long-term in culture and serve as a reliable platform for mechanistic studies on alveolar epithelial repair, surfactant metabolism, and cellular responses to lung injury, toxins, and therapeutic agents.