Ventilator-induced lung injury (VILI) is a common cause of the morbidity and mortality associated with excessive lung cell stretch produced by mechanical ventilation. High permeability pulmonary edema is a cardinal feature of VILI, however, the mechanisms involved are unclear. These changes likely involve direct damage to endothelial cells (EC) or """"""""stress failure"""""""", as well as subtle events involving EC signaling pathways which modulate by an actin-based system that effects cell contraction and stress fiber formation. We hypothesize that endothelial cells exposed to excessive cyclic stretch undergo phenotypic changes that result in increased contractile protein expression resulting in enhanced agonist-driven contractility and permeability. Utilizing an in vitro model, human pulmonary artery endothelial cells (HPAEC) and human microvascular endothelial cells (HMEC) will be exposed to cyclic stretch (5% and 18% radial elongation).
In specific aim #1, we will characterize the time- and strain-dependent effect of stretch on macro and micro lung EC.
In specific aim #2, using Affymetrix cDNA microarrays, we will determine altered contractile protein gene expression patterns modified by cyclic stretch. EC contraction is often regulated by EC myosin light chain kinase (MLCK), an enzyme first cloned by the sponsor's laboratory that drives myosin light chain phosphorylation, a precursor of actomyosin contraction.
In specific aim #3, the role of MLCK in EC barrier dysfunction after stretch will be investigated with measures of MLCK activity and elaboration of the effects of pharmacologic inhibitors as well as and overexpression of MLCK mutant constructs. These studies, which define EC biochemical and genomic response to cyclic stretch, may result in new therapeutic strategies that target VILI.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32HL071411-01
Application #
6552794
Study Section
Special Emphasis Panel (ZRG1-F10 (20))
Program Officer
Colombini-Hatch, Sandra
Project Start
2003-01-23
Project End
Budget Start
2002-07-24
Budget End
2003-07-23
Support Year
1
Fiscal Year
2002
Total Cost
$52,084
Indirect Cost
Name
Johns Hopkins University
Department
Public Health & Prev Medicine
Type
Schools of Public Health
DUNS #
045911138
City
Baltimore
State
MD
Country
United States
Zip Code
21218
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