Identification of glucocorticoid- and adenovirus E1A-regulated genes in lung epithelial cells by differential display.
Adenovirus infection has been implicated in the pathogenesis of lung inflammatory diseases for which glucocorticoids provide effective antiinflammatory treatment. In this study, the differential display assay was used to identify messenger RNAs (mRNAs) differentially expressed in dexamethasone (1 microM for 24 h)-treated A549 lung epithelial cells compared to A549 cells transfected with the adenoviral E1A gene. Thirty-seven complimentary DNAs (cDNAs) (15 glucocorticoid-regulated, 22 adenovirus E1A-regulated) were isolated. DNA sequence analysis showed that 35 of these were unique, 2 were identical with each other, and 3 were common to the glucocorticoid- and E1A-regulated groups. Genes identified included those involved in transcription/translation, cytoskeletal/contractile element genes, metabolic enzyme genes, and genes associated with cell regulation/signal transduction. After further analysis of the isolated clones by Northern blotting, ribonuclease protection, and semiquantitative RT-PCR (reverse transcriptase-polymerase chain reaction), 10 of the 14 glucocorticoid-regulated and one of the three common to both the adenovirus E1A- and glucocorticoid-regulated cDNAs were confirmed for this control of their expression. We conclude that the strategy of identifying cDNAs regulated by both adenovirus E1A and glucocorticoids provides a promising approach for identifying genes that may be important in the pathogenesis of lung inflammation and therefore targets for glucocorticoid treatment.