The Influence of Human Respiratory Epithelia on Pseudomonas aeruginosa Gene Expression

To gain insights into the initial phases of P. aeruginosa infections and to identify P. aeruginosa genes regulated in response to respiratory epithelia we exposed P. aeruginosa to cultured primary differentiated human airway epithelia. We used a P. aeruginosa strain (PAO1) that causes acute damage to the epithelia and a mutant (PAOSC11) with defects in Type III secretion and in rhamnolipid synthesis. The mutant did not cause rapid damage to epithelia as did the wildtype. Keywords: Pseudomonas aeruginosa and respiratory epithelia We performed three comparisons: First comparison:To identify genes regulated in the initial phase of an acute P. aeruginosa infection, we performed transcriptome analyses of wildtype PAO1 co-incubated with respiratory epithelia. For a baseline comparison we used wildtype P. aeruginosa PAO1 grown in broth culture. Second comparison:To identify genes regulated in the initial phase of a chronic P. aeruginosa infection (an infection that does not result in acute injury to the epithelium), transcriptome analyses were done with the TTSS, rhamnolipid synthesis mutant (PAOSC11) co-incubated with respiratory epithelia in our in vitro infection model. For a baseline comparison we used PAOSC11 grown in broth culture. Third comparison: We compared the transcript profiles of wildtype PAO1 exposed to epithelia and the PAOSC11 mutant exposed to epithelia.