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

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Gharib, S. A. Articles by Altemeier, W. A. PubMed Articles by Gharib, S. A. Articles by Altemeier, W. A.

Dissecting the Lung's Transcriptional Program during Noninjurious Mechanical Ventilation

¹ Department of Medicine, University of Washington School of Medicine, Seattle, Washington; and ² Department of Medicine, University of Toronto, Toronto, Ontario, Canada

Correspondence and requests for reprints should be addressed to William A. Altemeier, M.D., Box 356522, 1959 NE Pacific St., Seattle, WA 98115. E-mail: billa{at}u.washington.edu

The role of mechanical ventilation (MV) with moderate tidal volumes in the pathogenesis of acute lung injury (ALI) is not fully understood. We hypothesized that noninjurious MV initiates a pro-inflammatory transcriptional program in the lung. Twelve mice were randomized to MV (tidal volume, 10 ml/kg; positive end-expiratory pressure, 0 cm H₂O; FI_O2, 0.21) or spontaneous breathing (Control). After 4 hours, total RNA was isolated from whole lungs and each sample hybridized to an Affymetrix MOE 430A GeneChip (Santa Clara, CA). Multidimensional scaling and gene ontology analysis of differentially expressed genes was performed. Gene–gene interaction network analysis was undertaken to identify key transcription factors activated during MV. Our computational results were confirmed with electrophoretic mobility shift assays (EMSA) and with whole-lung chromatin immunoprecipitation (ChIP) assay. Despite the overt absence of lung injury, MV resulted in the differential expression of over 700 genes, providing a distinct transcriptional signature. A gene–gene interaction network comprising 175 differentially expressed genes was computationally constructed and noted to be highly enriched for pro-inflammatory pathways. Four critical nodes were identified in this network corresponding to JUN, FOS, MYC, and RELA. EMSA confirmed AP-1 DNA binding in nuclear extracts from ventilated mice. Recruitment of JunD to the promoter of F3 (tissue factor), a lung injury–associated gene, which is up-regulated by MV, was confirmed by ChIP assay. MV at a tidal volume of 10 ml/kg activates a pro-inflammatory transcriptional program in the lung, potentially making it highly susceptible to ALI in the presence of a secondary insult. Using a novel computational framework, we systematically dissected these MV-activated programs and their transcriptional regulators, thereby identifying potential targets for modulating ventilator-associated lung injury.

FOOTNOTES

Funding: National Institutes of Health Grants HL074223 (S.A.G.), HL071020 (W.A.A.), HL073996, and HL072370 (W.C.L.). W.C.L. is supported by a Canada Research Chair in Infectious Disease and Inflammation from the Canadian Institutes of Health Research.

Conflict of Interest Statement: None of the authors has a financial relationship with a commercial entity that has an interest in the subject of this manuscript.

(Received in original form August 3, 2007; accepted in final form October 16, 2007)

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Gharib, S. A. Articles by Altemeier, W. A. PubMed Articles by Gharib, S. A. Articles by Altemeier, W. A.