-ATPase Function in A549 Cells

We hypothesized that viral mediated transfer of Na 1 ,K 1 -ATPase subunit genes to alveolar epithelial cells to overexpress Na 1 ,K 1 -ATPase could increase Na 1 ,K 1 -ATPase function. We produced replication-deficient human type 5 adenoviruses that contained cytomegalovirus (CMV)-driven cDNAs for the rat a 1 and b 1 subunits of Na 1 ,K 1 -ATPase (AdMRCMV a 1 and AdMRCMV b 1 , respectively). These viruses were used to transduce human adenocarcinoma cells (A549) in culture. Na 1 ,K 1 -ATPase function was increased by 2.5-fold in the AdMRCMV a 1 -infected cells. Sham and AdMRCMV b 1 -infected cells, and cells infected by a CMV-driven b -galactosidase-expressing adenovirus, had no increases in Na 1 ,K 1 -ATPase activity. A549 cells infected with multiplicities of infection of 10–200 of AdMRCMV a 1 demonstrated expression of a rat a 1 mRNA and increased a 1 protein; no change in b 1 message or protein was noted. Ouabain sensitivity was measured in A549 cells following infection with AdMRCMV a 1 . In contrast to controls, AdMRCMV a 1 -infected cells demonstrated two IC 50 s. The first was similar to the IC 50 s of the controls; the second IC 50 was 2 logs greater than the first, consistent with the presence of both the rat and human a 1 isozymes. These results demonstrate for the first time that adenoviruses can be used to augment Na 1 ,K 1 ATPase function. Factor, P., C. Senne, V. Dumasius, K. Ridge, H. A. Jaffe, B. Uhal, Z. Gao, and J. I. Sznajder. 1998. Overexpression of the Na 1 ,K 1 -ATPase a 1 subunit increases Na 1 ,K 1 -ATPase function in A549 cells. Am. J. Respir. Cell Mol. Biol. 18:741–749.