HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 291/6/L1246    most recent 00016.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Baleeiro, C. E. O. Articles by Paine, R. Search for Related Content PubMed PubMed Citation Articles by Baleeiro, C. E. O. Articles by Paine, R., III

GM-CSF and the impaired pulmonary innate immune response following hyperoxic stress

¹Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, and ²Department of Veterans Affairs Medical Center, Ann Arbor, Michigan

Submitted 11 January 2006 ; accepted in final form 28 July 2006

We have previously demonstrated that mice exposed to sublethal hyperoxia (an atmosphere of >95% oxygen for 4 days, followed by return to room air) have significantly impaired pulmonary innate immune response. Alveolar macrophages (AM) from hyperoxia-exposed mice exhibit significantly diminished antimicrobial activity and markedly reduced production of inflammatory cytokines in response to stimulation with LPS compared with AM from control mice in normoxia. As a consequence of these defects, mice exposed to sublethal hyperoxia are more susceptible to lethal pneumonia with Klebsiella pneumoniae than control mice. Granulocyte/macrophage colony-stimulating factor (GM-CSF) is a growth factor produced by normal pulmonary alveolar epithelial cells that is critically involved in maintenance of normal AM function. We now report that sublethal hyperoxia in vivo leads to greatly reduced alveolar epithelial cell GM-CSF expression. Systemic treatment of mice with recombinant murine GM-CSF during hyperoxia exposure preserved AM function, as indicated by cell surface Toll-like receptor 4 expression and by inflammatory cytokine secretion following stimulation with LPS ex vivo. Treatment of hyperoxic mice with GM-CSF significantly reduced lung bacterial burden following intratracheal inoculation with K. pneumoniae, returning lung bacterial colony-forming units to the level of normoxic controls. These data point to a critical role for continuous GM-CSF activity in the lung in maintenance of normal AM function and demonstrate that lung injury due to hyperoxic stress results in significant impairment in pulmonary innate immunity through suppression of alveolar epithelial cell GM-CSF expression.

lung; macrophage; inflammation; alveolar epithelial cell; acute respiratory distress syndrome; granulocyte/macrophage colony-stimulating factor

This article has been cited by other articles:

				M. N. Ballinger, L. L. N. Hubbard, T. R. McMillan, G. B. Toews, M. Peters-Golden, R. Paine III, and B. B. Moore Paradoxical role of alveolar macrophage-derived granulocyte-macrophage colony-stimulating factor in pulmonary host defense post-bone marrow transplantation Am J Physiol Lung Cell Mol Physiol, July 1, 2008; 295(1): L114 - L122. [Abstract] [Full Text] [PDF]