Pseudomonas aeruginosa Pyocyanin Is Critical for Lung Infection in Mice

ABSTRACT Pseudomonas aeruginosa secretes copious amounts of the redox-active phenazine, pyocyanin (PCN), during cystic fibrosis lung infection. PCN has been shown to interfere with a variety of cellular processes in cultured lung epithelial cells. Here, by using two respiratory tract models of infection, we demonstrate that PCN mediates tissue damage and necrosis during lung infection.

Download Full-text

Inhibition of Adhesion and Invasion of Pseudomonas aeruginosa to Lung Epithelial Cells: A Model of Cystic Fibrosis Infection

Lung Diseases - Selected State of the Art Reviews ◽

10.5772/30557 ◽

2012 ◽

Author(s):

Ayman M. ◽

Ghada Sawy ◽

Walid Elkhatib ◽

Ehab Noreddin ◽

Atef Shibl

Keyword(s):

Cystic Fibrosis ◽

Pseudomonas Aeruginosa ◽

Epithelial Cells ◽

Lung Epithelial Cells ◽

Lung Epithelial ◽

Adhesion And Invasion

Download Full-text

Tristetraprolin regulates IL-8 mRNA stability in cystic fibrosis lung epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.90601.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. L1012-L1018 ◽

Cited By ~ 27

Author(s):

Nagaraja Sethuraman Balakathiresan ◽

Sharmistha Bhattacharyya ◽

Usha Gutti ◽

Robert P. Long ◽

Catherine Jozwik ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Mrna Stability ◽

Posttranscriptional Regulation ◽

Lung Epithelial Cells ◽

Cellular Phenotype ◽

Lung Epithelial ◽

Vitro Analysis ◽

In Vitro Analysis

Cystic fibrosis (CF) is due to mutations in the CFTR gene and is characterized by hypersecretion of the proinflammatory chemokine IL-8 into the airway lumen. Consequently, this induces the highly inflammatory cellular phenotype typical of CF. Our initial studies revealed that IL-8 mRNA is relatively stable in CF cells compared with those that had been repaired with [WT]CFTR (wild-type CFTR). Relevantly, the 3′-UTR of IL-8 mRNA contains AU-rich sequences (AREs) that have been shown to mediate posttranscriptional regulation of proinflammatory genes upon binding to ARE-binding proteins including Tristetraprolin (TTP). We therefore hypothesized that very low endogenous levels of TTP in CF cells might be responsible for the relative stability of IL-8 mRNA. As predicted, increased expression of TTP in CF cells resulted in reduced stability of IL-8 mRNA. An in vitro analysis of IL-8 mRNA stability in CF cells also revealed a TTP-induced enhancement of deadenylation causing reduction of IL-8 mRNA stability. We conclude that enhanced stability of IL-8 mRNA in TTP-deficient CF lung epithelial cells serve to drive the proinflammatory cellular phenotype in the CF lung.

Download Full-text

MAPK signaling pathways regulate IL-8 mRNA stability and IL-8 protein expression in cystic fibrosis lung epithelial cell lines

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00051.2010 ◽

2011 ◽

Vol 300 (1) ◽

pp. L81-L87 ◽

Cited By ~ 32

Author(s):

Sharmistha Bhattacharyya ◽

Usha Gutti ◽

Jose Mercado ◽

Chad Moore ◽

Harvey B. Pollard ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Protein Expression ◽

Signaling Pathways ◽

Mrna Stability ◽

Mapk Signaling ◽

Lung Epithelial Cells ◽

Lung Epithelial ◽

The Stability ◽

Mapk Signaling Pathways

Cystic fibrosis (CF) is characterized by a massive proinflammatory phenotype in the lung, caused by mutations in the CFTR gene. IL-8 and other proinflammatory mediators are elevated in the CF airway, and the immediate mechanism may depend on disease-specific stabilization of IL-8 mRNA in CF lung epithelial cells. MAPK signaling pathways impact directly on IL-8 protein expression in CF cells, and we have hypothesized that the mechanism may also involve stabilization of the IL-8 mRNA. To test this hypothesis, we have examined the effects of pharmacological and molecular inhibitors of p38, and downstream MK2, ERK1/2, and JNK, on stability of IL-8 mRNA in CF lung epithelial cells. We previously showed that tristetraprolin (TTP) was constitutively low in CF and that raising TTP destabilized the IL-8 mRNA. We therefore also tested these effects on CF lung epithelial cells stably expressing TTP. TTP binds to AU-rich elements in the 3′-UTR of the IL-8 mRNA. We find that inhibition of p38 and ERK1/2 reduces the stability of IL-8 mRNA in parental CF cells. However, neither intervention further lowers TTP-dependent destabilization of IL-8 mRNA. By contrast, inhibition of the JNK-2 pathway has no effect on IL-8 mRNA stability in parental CF cell, but rather increases the stability of the message in cells expressing high levels of TTP. However, we find that inhibition of ERK1/2 or p38 leads to suppression of the effect of JNK-2 inhibition on IL-8 mRNA stability. These data thus lend support to our hypothesis that constitutive MAPK signaling and proteasomal activity might also contribute, along with aberrantly lower TTP, to the proinflammatory phenotype in CF lung epithelial cells by increasing IL-8 mRNA stability and IL-8 protein expression.

Download Full-text

077 Oxidative stress induces ERK1/2 MAP kinase but not NF̃vB activation in cystic fibrosis lung epithelial cells: potential mechanism for excessive IL-8 secretion

Revue des Maladies Respiratoires ◽

10.1016/s0761-8425(07)74368-1 ◽

2007 ◽

Vol 24 (9) ◽

pp. 1230

Author(s):

E. Boncœur ◽

E. Bonvin ◽

V. Saint Criq ◽

C. Muselet-Charlier ◽

D.C. Gruenert ◽

...

Keyword(s):

Oxidative Stress ◽

Cystic Fibrosis ◽

Epithelial Cells ◽

Map Kinase ◽

Lung Epithelial Cells ◽

Cystic Fibrosis Lung ◽

Potential Mechanism ◽

Lung Epithelial

Download Full-text

Involvement of phospholipase A2 in Pseudomonas aeruginosa-mediated PMN transepithelial migration

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00390.2005 ◽

2006 ◽

Vol 290 (4) ◽

pp. L703-L709 ◽

Cited By ~ 21

Author(s):

Bryan P. Hurley ◽

Natecia L. Williams ◽

Beth A. McCormick

Keyword(s):

Pseudomonas Aeruginosa ◽

Epithelial Cells ◽

Lung Epithelial Cells ◽

Polymorphonuclear Cells ◽

Diacylglycerol Lipase ◽

Rate Limiting Step ◽

Lung Epithelial ◽

Human Pmns ◽

Epithelial Barriers ◽

Rate Limiting

Inflammation resulting from bacterial infection of the respiratory mucosal surface during pneumonia and cystic fibrosis contributes to pathology. A major consequence of the inflammatory response is recruitment of polymorphonuclear cells (PMNs) to the infected site. To reach the airway, PMNs must travel through several cellular and extracellular barriers, via the actions of multiple cytokines, chemokines, and adhesion molecules. Using a model of polarized lung epithelial cells (A549 or Calu-3) grown on Transwell filters and human PMNs, we have shown that Pseudomonas aeruginosa induces PMN migration across lung epithelial barriers. The process is mediated by epithelial production of the eicosanoid hepoxilin A3 (HXA3) in response to P. aeruginosa infection. HXA3 is a PMN chemoattractant metabolized from arachidonic acid (AA). Given that release of AA is believed to be the rate-limiting step in generating eicosanoids, we investigated whether P. aeruginosa infection of lung epithelial cells resulted in an increase in free AA. P. aeruginosa infection of A549 or Calu-3 monolayers resulted in a significant increase in [3H]AA released from prelabeled lung epithelial cells. This was partially inhibited by PLA2 inhibitors ONO-RS-082 and ACA as well as an inhibitor of diacylglycerol lipase. Both PLA2 inhibitors dramatically reduced P. aeruginosa-induced PMN transmigration, whereas the diacylglycerol lipase inhibitor had no effect. In addition, we observed that P. aeruginosa infection caused an increase in the phosphorylation of cytosolic PLA2 (cPLA2), suggesting a mechanism whereby P. aeruginosa activates cPLA2 generating free AA that may be converted to HXA3, which is required for mediating PMN transmigration.

Download Full-text