Abstract
We explored the mechanistic involvement of the growth arrest and DNA damage-inducible gene GADD45a in lipopolysaccharide (LPS)- and ventilator-induced inflammatory lung injury (VILI). Multiple biochemical and genomic parameters of inflammatory lung injury indicated that GADD45a -/- mice are modestly susceptible to intratracheal LPS-induced lung injury and profoundly susceptible to high tidal volume VILI, with increases in microvascular permeability and bronchoalveolar lavage levels of inflammatory cytokines. Expression profiling of lung tissues from VILI-challenged GADD45a-/- mice revealed strong dysregulation in the B-cell receptor signaling pathway compared with wild-type mice and suggested the involvement of PI3 kinase/Akt signaling components. Western blot analyses of lung homogenates confirmed ∼50% reduction in Akt protein levels in GADD45a-/- mice accompanied by marked increases in Akt ubiquitination. Electrical resistance measurements across human lung endothelial cell monolayers with either reduced GADD45a or Akt expression (siRNAs) revealed significant potentiation of LPS-induced human lung endothelial barrier dysfunction, which was attenuated by overexpression of a constitutively active Akt1 transgene. These studies validate GADD45a as a novel candidate gene in inflammatory lung injury and a significant participant in vascular barrier regulation via effects on Akt-mediated endothelial signaling.
Original language | English (US) |
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Pages (from-to) | 1325-1337 |
Number of pages | 13 |
Journal | FASEB Journal |
Volume | 23 |
Issue number | 5 |
DOIs | |
State | Published - May 2009 |
Funding
Keywords
- Biomarker
- Mechanical ventilation
- Ubiquitination
- Vascular barrier regulation
ASJC Scopus subject areas
- Genetics
- Molecular Biology
- Biochemistry
- Biotechnology