This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Pena, J.
Right arrow Articles by Machen, T. E.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Pena, J.
Right arrow Articles by Machen, T. E.

 Previous Article  |  Next Article 

Infection and Immunity, July 2009, p. 2857-2865, Vol. 77, No. 7
0019-9567/09/$08.00+0     doi:10.1128/IAI.01355-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Pseudomonas aeruginosa Inhibition of Flagellin-Activated NF-{kappa}B and Interleukin-8 by Human Airway Epithelial Cells {triangledown}

Jose Pena, Zhu Fu, Christian Schwarzer, and Terry E. Machen*

Department of Molecular and Cell Biology, University of California, Berkeley, California 94720-3200

Received 5 November 2008/ Returned for modification 4 March 2009/ Accepted 2 May 2009

Pseudomonas aeruginosa-induced activation of NF-{kappa}B and secretion of proinflammatory cytokines by airway epithelial cells require that the bacteria express flagellin. We tested whether P. aeruginosa and human airway epithelial cells secrete factors that modulated this response. Experiments were performed with both the Calu-3 cell line and primary cultures of tracheal epithelial cells. P. aeruginosa strain PAK {Delta}fliC (flagellin knockout) did not activate NF-{kappa}B or interleukin-8 (IL-8) but inhibited flagellin-activated NF-{kappa}B by 40 to 50% and IL-8 secretion by 20 to 25%. PAK {Delta}fliC also inhibited NF-{kappa}B induced by IL-1β and Toll-like receptor 2 agonist Pam3CSK4. Similar inhibitions were observed with strains PAK, PAO1, and PA14. The inhibitory factor was present in conditioned medium isolated from PAK {Delta}fliC or Calu-3 plus PAK {Delta}fliC, but it was not present in conditioned medium isolated from Calu-3 cells alone or from PAK {Delta}fliC that had been heat treated. Inhibition by PAK {Delta}fliC-conditioned medium was exerted from either the apical or the basolateral side of the epithelium, was enhanced in simple Ringer's solution over that in tissue culture medium, and did not result from altered pH or depletion of glucose. The inhibitory effect of conditioned medium was abolished by boiling and appeared from filtration studies to result from effects of a factor with a molecular mass of <3 kDa. These and further studies with isogenic mutants led to the conclusion that the NF-{kappa}B and IL-8 response of airway epithelial cells to P. aeruginosa results from a balance of proinflammatory effects of flagellin and antiinflammatory effects of a small (<3-kDa), heat-sensitive factor(s) that is not lipopolysaccharide, C12 homoserine lactone, alginate, CIF, or exotoxin A, S, T, U, or Y.

* Corresponding author. Mailing address: Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200. Phone: (510) 642-2983. Fax: (510) 643-6791. E-mail: tmachen{at}berkeley.edu

{triangledown} Published ahead of print on 18 May 2009.

Editor: J. L. Flynn

Infection and Immunity, July 2009, p. 2857-2865, Vol. 77, No. 7
0019-9567/09/$08.00+0     doi:10.1128/IAI.01355-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»