The Effect of Pseudomonas aeruginosa on the Endoplasmic Reticulum Stress Response in Mammalian Cells

Abstract

Pseudomonas aeruginosa is an opportunistic pathogen imposing serious threat to cystic fibrosis patients. P. aeruginosa is equipped with many virulence factors that are controlled by the quorum sensing (QS) systems. These virulence factors modulate host responses such as the host stress responses. I demonstrated that P. aeruginosa wild-type (WT) strain PA14 activated the stress responses in A549 cells. Screening the mutants of different QS systems showed that a deletion in the QS regulator gene lasR led to a prolonged activation of the stress response compared to WT. Mutants of LasB and AprA, two LasR-regulated proteases, showed a delayed and lower levels of stress response activation compared to WT. Purified LasB treatment was sufficient to induce ISR in A549 cells, suggesting that it is a novel elicitor of this host stress response. My work indicates that P. aeruginosa is a pathological stressor which will help in the search of novel therapy.