Glycogen synthase kinase-3 mediates endothelial cell activation by tumor necrosis factor-alpha.
BACKGROUND
Endothelial cell transformation to a thrombogenic and inflammatory phenotype plays an important role in the pathogenesis of atherothrombosis, but the responsible signaling pathways remain to be elucidated. This study was designed to investigate the regulatory role of glycogen synthase kinase-3 (GSK-3) in tissue factor (TF) and vascular cell adhesion molecule (VCAM)-1 expression in tumor necrosis factor (TNF)-alpha-stimulated endothelial cells.


RESULTS
In human endothelial cells, TNF-alpha as well as thrombin induced rapid and transient dephosphorylation and hence, activation of GSK-3. A GSK-3 inhibitor, LiCl, suppressed TNF-alpha- and thrombin-induced TF and VCAM-1 expression, whereas NaCl had no effect. A specific GSK-3 inhibitor, TDZD-8, mimicked the inhibitory effects of lithium. GSK-3 inhibition also significantly suppressed the TNF-alpha-induced increase in TF activity and VCAM-1 cell-surface expression. The luciferase reporter system demonstrated that regulation of TF and VCAM-1 expression by GSK-3 was mediated at the transcriptional level. The TNF-alpha-induced increase in nuclear factor (NF)-kappaB DNA-binding activity was significantly suppressed by TDZD-8. TDZD-8 completely prevented the TNF-alpha-induced inhibitor of NF-kappaB (IkappaB)-alpha degradation but had no effect on IkappaB-kinase-beta phosphorylation.


CONCLUSIONS
GSK-3 regulates TNF-alpha-induced IkappaB-alpha degradation and NF-kappaB activation independent of IkappaB-kinase-beta and subsequent induction of TF and VCAM-1 expression in human endothelial cells. This study provides the experimental basis for a novel strategy of using GSK-3 inhibition to treat atherothrombotic vascular disease.
Eto
Masato
M
Department of Cardiology, Cardiovascular Center, University Hospital, Cardiovascular Research, Institute of Physiology, University of Zurich, Zurich, Switzerland.
Kouroedov
Alexei
A
Cosentino
Francesco
F
Lüscher
Thomas F
TF
D002478:Cells, Cultured; D042783:Endothelial Cells / Q000187:drug effects* / Q000502:physiology; D005786:Gene Expression Regulation; D038362:Glycogen Synthase Kinase 3 / Q000502:physiology*; D006801:Humans; D020672:I-kappa B Proteins / Q000378:metabolism; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000502:physiology; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D051057:Proto-Oncogene Proteins c-akt / Q000502:physiology; D013925:Thromboplastin / Q000235:genetics; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019010:Vascular Cell Adhesion Molecule-1 / Q000235:genetics
D020672:I-kappa B Proteins; D016328:NF-kappa B; C000606204:NFKBIA protein, human; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D000072000:NF-KappaB Inhibitor alpha; D013925:Thromboplastin; D051057:Proto-Oncogene Proteins c-akt; D038362:Glycogen Synthase Kinase 3