Interaction of Pseudomonas aeruginosa with epithelial cells: Identification of differentially regulated genes by expression microarray analysis of human cDNAs

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen that plays a major role in lung function deterioration in cystic fibrosis patients. To identify critical host responses during infection, we have used high-density DNA microarrays, consisting of 1,506 human cDNA clones, to monitor gene expression in the A549 lung pneumocyte cell line during exposure to P. aeruginosa. We have identified host genes that are differentially expressed upon infection, several of which require interaction with P. aeruginosa and the expression of the major subunit of type IV pili, PilA. Differential expression of genes involved in various cellular functions was identified, and we selected the gene encoding the transcription factor interferon regulatory factor 1 (IRF-1) for further analysis. The levels of the IRF-1 transcript increased 3-to 4-fold in A549 cells after adherence by P. aeruginosa. A similar increase of IRF-1 mRNA was observed in A549 cells exposed to wild-type P. aeruginosa when compared to an isogenic, nonpiliated strain. However, this difference was abolished when serum was present during the incubation of bacteria. Exposure of A549 cells to purified P. aeruginosa lipopolysaccharide did not result in a significant increase in IRF-1 mRNA. Although the P. aeruginosa-induced increased IRF-1 expression depends on the presence of bacterial adhesin, our findings do not preclude the possibility that other bacterial products are responsible for IRF-1 activation, which is enhanced by bacterial adherence to cells. These data show that microarray technology can be an important tool for studying the complex interplay between bacterial pathogens and host.

Pseudomonas aeruginosa Flagellin and Alginate Elicit Very Distinct Gene Expression Patterns in Airway Epithelial Cells: Implications for Cystic Fibrosis Disease

“…A previous analysis of the interaction of P. aeruginosa with type II pneumocytelike human airway epithelial cells (3) exposed A549 cells to the motile wild-type strain PAK (70) and the isogenic type IV pili mutant PAK-NP (a pilA mutant, defective in adherence to epithelial cells) (71). In this study, which was more limited than ours in the scope of genes interrogated, the increased expression of a limited number of these proinflammatory genes was dependent to some degree on adherence (3). Furthermore, a recent study of CF airway epithelial cells exposed to P. aeruginosa suggests that flagellin, and not pilin, is the factor responsible for cytokine gene up-regulation (5).…”

“…A number of P. aeruginosa virulence factors, including flagella, pili, LPS, quorum-sensing molecules, proteases, toxins, and others, are critical in the establishment of acute infections, as well as in chronic lung infections associated with cystic fibrosis (CF) 4 (1,2). This repertoire of virulence factors promotes adherence to host cells, damages host tissues, elicits inflammation, and possibly disrupts host defenses by altering gene expression in host cells (3)(4)(5). P. aeruginosa environmental strains are usually flagellated and therefore motile, in contrast to many CF isolates (6).…”

Regulation of Matrilysin Expression in Airway Epithelial Cells by Pseudomonas aeruginosa Flagellin

“…Indeed, expression of human BD-2 in human colon epithelial cells is induced by Salmonella enteritidis flagellin (34). Insight into the response of respiratory epithelial cells to airway pathogens has recently been provided by microarray analysis of genes differentially expressed after infection with P. aeruginosa and Bordetella pertussis, illustrating the potent pro-inflammatory response mounted by epithelial cells upon interaction with bacteria (35,36). Therefore, our data include matrilysin in the panoply of genes induced early and strongly by bacterial exposure.…”

Cag pathogenicity island-specific responses of gastric epithelial cells to Helicobacter pylori infection

“…A common finding in many of these investigations is up-regulation of genes involved in the inflammatory response (17)(18)(19). This pattern is not restricted to cells of the immune system but can be elicited in epithelial cells as well (20,21). Beyond a common innate immune response to infection, different cells may have characteristic signatures to different pathogens, often as the result of the highly specific activities of a particular pathogen's virulence determinants.…”