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

TitleGADD45a promoter regulation by a functional genetic variant associated with acute lung injury.
Publication TypeJournal Article
Year of Publication2014
AuthorsMitra S, Wade MS, Sun X, Moldobaeva N, Flores C, Ma S-F, Zhang W, Garcia JGN, Jacobson JR
JournalPLoS One
Date Published2014
ISSN Number1932-6203
KeywordsAcute Lung Injury, Adult, Aged, Animals, Binding Sites, Cell Cycle Proteins, Endothelial Cells, Female, Gene Dosage, Gene Expression Regulation, Genes, Reporter, Heterozygote, Humans, Interferon Regulatory Factor-7, Luciferases, Lung, Male, Mechanotransduction, Cellular, Mice, Mice, Knockout, Middle Aged, Nuclear Proteins, Polymorphism, Single Nucleotide, Promoter Regions, Genetic, Protein Binding, Sp1 Transcription Factor, Stress, Mechanical, Ventilator-Induced Lung Injury

<p><b>RATIONALE: </b>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.</p><p><b>OBJECTIVES: </b>We examined mechanical stress-dependent regulatory elements (MSRE) in the GADD45a promoter and the contribution of promoter polymorphisms in GADD45a expression and ALI susceptibility.</p><p><b>METHODS AND RESULTS: </b>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.</p><p><b>CONCLUSION: </b>These results strongly support a functional role for GADD45a in ALI/VILI and identify a specific gene variant that confers risk for ALI.</p>

Alternate JournalPLoS ONE
PubMed ID24940746
PubMed Central IDPMC4062486
Grant ListUL1 TR000430 / TR / NCATS NIH HHS / United States