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PLoS One. 2014 Jun 18;9(6):e100169. doi: 10.1371/journal.pone.0100169. eCollection 2014.

GADD45a promoter regulation by a functional genetic variant associated with acute lung injury.

Author information

1
Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America.
2
Centro de Investigacion Biomedica en red Enfermedades Respiratorias, Instituto de Salud Carlos III, Madrid, Spain; Research Unit, Hospital Universitario Nuestra Senora de Candelaria, Tenerife, Spain.
3
Division of Pulmonary, Critical Care and Sleep, University of Chicago, Chicago, Illinois, United States of America.
4
Division of Pulmonary, Critical Care, Sleep and Allergy, Department of Medicine, University of Illinois at Chicago, Chicago, Illinois, United States of America; Department of Pediatrics, University of Illinois at Chicago, Chicago, Illinois, United States of America.
5
Arizona Health Sciences Center, University of Arizona, Tucson, Arizona, United States of America.

Abstract

RATIONALE:

Growth arrest DNA damage inducible alpha (GADD45a) is a stress-induced gene we have shown to participate in the pathophysiology of ventilator-induced lung injury (VILI) via regulation of mechanical stress-induced Akt ubiquitination and phosphorylation. The regulation of GADD45a expression by mechanical stress and its relationship with acute lung injury (ALI) susceptibility and severity, however, remains unknown.

OBJECTIVES:

We examined mechanical stress-dependent regulatory elements (MSRE) in the GADD45a promoter and the contribution of promoter polymorphisms in GADD45a expression and ALI susceptibility.

METHODS AND RESULTS:

Initial studies in GADD45a knockout and heterozygous mice confirmed the relationship of GADD45a gene dose to VILI severity. Human lung endothelial cells (EC) transfected with a luciferase vector containing the full length GADD45a promoter sequence (-771 to +223) demonstrated a >4 fold increase in GADD45a expression in response to 18% cyclic stretch (CS, 4 h) compared to static controls while specific promoter regions harboring CS-dependent MSRE were identified using vectors containing serial deletion constructs of the GADD45a promoter. In silico analyses of GADD45a promoter region (-371 to -133) revealed a potential binding site for specificity protein 1 (SP1), a finding supported by confirmed SP1 binding with the GADD45a promoter and by the significant attenuation of CS-dependent GADD45a promoter activity in response to SP1 silencing. Separately, case-control association studies revealed a significant association of a GADD45a promoter SNP at -589 (rs581000, G>C) with reduced ALI susceptibility. Subsequently, we found allelic variation of this SNP is associated with both differential GADD45a expression in mechanically stressed EC (18% CS, 4 h) and differential binding site of interferon regulatory factor 7 (IRF7) at this site.

CONCLUSION:

These results strongly support a functional role for GADD45a in ALI/VILI and identify a specific gene variant that confers risk for ALI.

PMID:
24940746
PMCID:
PMC4062486
DOI:
10.1371/journal.pone.0100169
[Indexed for MEDLINE]
Free PMC Article
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