Pseudomonas aeruginosa pyocyanin activates NRF2-ARE-mediated transcriptional response via the ROS-EGFR-PI3K-AKT/MEK-ERK MAP kinase signaling in pulmonary epithelial cells

PLoS One. 2013 Aug 27;8(8):e72528. doi: 10.1371/journal.pone.0072528. eCollection 2013.

Abstract

The redox-active pyocyanin (PCN) secreted by the respiratory pathogen Pseudomonas aeruginosa generates reactive oxygen species (ROS) and causes oxidative stress to pulmonary epithelial cells. Nuclear factor (erythroid-derived 2)-like 2 (NRF2) confers protection against ROS-mediated cell death by inducing the expression of detoxifying enzymes and proteins via its binding to the cis-acting antioxidant response element (ARE). However, a clear relationship between NRF2 and PCN-mediated oxidative stress has not been established experimentally. In this study, we investigated the induction of NRF2-ARE response by PCN in the pulmonary epithelial cells. We analyzed the effect of PCN on NRF2 expression and nuclear translocation in cultured human airway epithelial cells, and in a mouse model of chronic PCN exposure. NRF2-dependent transcription of antioxidative enzymes was also assessed. Furthermore, we used inhibitors to examine the involvement of EGFR and its downstream signaling components that mediate NRF2-ARE-activation in response to PCN. PCN enhances the nuclear NRF2 accumulation and activates the transcription of ARE-mediated antioxidant genes. Furthermore, PCN activates NRF2 by inducing the EGFR-phosphoinositide-3-kinase (PI3K) signaling pathway and its main downstream effectors, AKT and MEK1/2-ERK1/2 MAP kinases. Inhibition of the EGFR-PI3K signaling markedly attenuates PCN-stimulated NRF2 accumulation in the nucleus. We demonstrate for the first time that PCN-mediated oxidative stress activates the EGFR-PI3K-AKT/MEK1/2-ERK1/2 MAP kinase signaling pathway, leading to nuclear NRF2 translocation and ARE responsiveness in pulmonary epithelial cells.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Animals
  • Antioxidant Response Elements*
  • Cell Line
  • Cell Nucleus / metabolism*
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • ErbB Receptors / metabolism*
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Humans
  • Lung / cytology
  • Lung / metabolism*
  • MAP Kinase Signaling System / drug effects*
  • Mice
  • NF-E2-Related Factor 2 / metabolism*
  • Oxidative Stress / drug effects
  • Phosphatidylinositol 3-Kinases / metabolism*
  • Proto-Oncogene Proteins c-akt / metabolism*
  • Pseudomonas aeruginosa / chemistry*
  • Pyocyanine / chemistry
  • Pyocyanine / pharmacology*
  • Reactive Oxygen Species / metabolism*
  • Transcription, Genetic / drug effects*

Substances

  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Nfe2l2 protein, mouse
  • Reactive Oxygen Species
  • Pyocyanine
  • EGFR protein, human
  • EGFR protein, mouse
  • ErbB Receptors
  • Proto-Oncogene Proteins c-akt
  • Extracellular Signal-Regulated MAP Kinases