Faculty Collaboration Database

Lipopolysaccharide-induced cytokine expression in alveolar epithelial cells: role of PKCζ-mediated p47phox phosphorylation. Chem Biol Interact 2011 Jan 15;189(1-2):72-81

Date

10/06/2010

Pubmed ID

20920494

DOI

10.1016/j.cbi.2010.09.026

Scopus ID

2-s2.0-79251550763 (requires institutional sign-in at Scopus site)   31 Citations

Abstract

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.

Author List

Leverence JT, Medhora M, Konduri GG, Sampath V

Authors

Girija Ganesh Konduri MD Chief, Professor in the Pediatrics department at Medical College of Wisconsin
Meetha Medhora Professor in the Radiation Oncology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acetophenones
Benzopyrans
Cell Line, Tumor
Enzyme Inhibitors
Enzyme-Linked Immunosorbent Assay
Humans
Immunoblotting
Intercellular Adhesion Molecule-1
Interleukin-8
Lipopolysaccharides
NADPH Oxidases
Naphthalenes
Oxidative Stress
Protein Kinase C
Pulmonary Alveoli
RNA, Messenger
Reverse Transcriptase Polymerase Chain Reaction
Signal Transduction
Superoxides
Tetradecanoylphorbol Acetate