Document Detail


Lipopolysaccharide-induced cytokine expression in alveolar epithelial cells: role of PKCζ-mediated p47phox phosphorylation.
MedLine Citation:
PMID:  20920494     Owner:  NLM     Status:  In-Process    
Abstract/OtherAbstract:
Chronic inflammation incited by bacteria in the saccular lung of premature infants contributes to the pathogenesis of bronchopulmonary dysplasia (BPD). LPS-mediated type II alveolar epithelial cell (AEC) injury induces the expression of pro-inflammatory cytokines that trigger pulmonary neutrophil influx, alveolar matrix degradation and lung remodeling. We hypothesized that NADPH oxidase (Nox)-dependent mechanisms mediate LPS-induced cytokine expression in AEC. We examined the role of p47phox in mediating LPS-dependent inflammatory cytokine expression in A549 cells (which exhibit phenotypic features characteristic of type II AEC) and elucidated the proximal signaling events by which Nox is activated by LPS. LPS-induced ICAM-1 and IL-8 expression was associated with increased superoxide formation in AEC. LPS-mediated oxidative stress and cytokine expression was inhibited by apocynin and augmented by PMA demonstrating that Nox-dependent redox signaling regulates LPS-dependent pro-inflammatory signaling in AEC. In LPS-treated cells, p47phox translocated from the cytoplasm to the perinuclear region and co-localized with gp91phox. LPS also induced a temporal increase in p47phox serine304 phosphorylation in AEC. While inhibition of classical PKC and novel PKC with calphostin and rottlerin did not inhibit ICAM-1 or IL-8 expression, the myristolyated PKCζ pseudosubstrate peptide (a specific inhibitor of PKCζ) inhibited LPS-induced cytokine expression in AEC. Inhibition of PKCζ also attenuated LPS-mediated p47phox phosphorylation and perinuclear translocation in AEC. Consistent with these data, LPS activated PKCζ in AEC as evidenced by increased threonine410 phophorylation. We conclude that PKCζ-mediated p47phox activation regulates LPS-dependent cytokine expression in AEC. Selective inhibition of PKCζ or p47phox might attenuate LPS-mediated inflammation and alveolar remodeling in BPD.
Authors:
Jeremy T Leverence; Meetha Medhora; Girija G Konduri; Venkatesh Sampath
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2010-10-30
Journal Detail:
Title:  Chemico-biological interactions     Volume:  189     ISSN:  1872-7786     ISO Abbreviation:  Chem. Biol. Interact.     Publication Date:  2011 Jan 
Date Detail:
Created Date:  2011-01-10     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0227276     Medline TA:  Chem Biol Interact     Country:  Ireland    
Other Details:
Languages:  eng     Pagination:  72-81     Citation Subset:  IM    
Copyright Information:
Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.
Affiliation:
Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI, United States.
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