Extracellular Signal-Regulated Kinase 5 SUMOylation Antagonizes Shear Stress–Induced Antiinflammatory Response and Endothelial Nitric Oxide Synthase Expression in Endothelial Cells

• Published in: Circulation research 2008-03, Vol.102 (5), p.538-545
• Main Authors: Woo, Chang-Hoon, Shishido, Tetsuro, McClain, Carolyn, Lim, Jae Hyang, Li, Jian-Dong, Yang, Jay, Yan, Chen, Abe, Jun-ichi
• Format: Article
• Language: English
• Subjects: Animals; Aorta - drug effects; Aorta - metabolism; Biological and medical sciences; Cells, Cultured; Diabetes Mellitus - chemically induced; Diabetes Mellitus - metabolism; Diabetes. Impaired glucose tolerance; Disease Models, Animal; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Endothelial Cells - metabolism; Enzyme Induction - drug effects; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Fundamental and applied biological sciences. Psychology; Glycation End Products, Advanced - pharmacology; Humans; Hydrogen Peroxide - pharmacology; Inflammation - metabolism; Male; Medical sciences; Mice; Mice, Inbred Strains; Mitogen-Activated Protein Kinase 7 - genetics; Mitogen-Activated Protein Kinase 7 - metabolism; Nitric Oxide Synthase Type III - metabolism; Oxidants - pharmacology; Protein Inhibitors of Activated STAT - antagonists & inhibitors; Protein Inhibitors of Activated STAT - metabolism; RNA, Small Interfering - pharmacology; Signal Transduction - drug effects; Signal Transduction - physiology; Streptozocin; Stress, Mechanical; SUMO-1 Protein - metabolism; Transcription, Genetic - drug effects; Vertebrates: cardiovascular system
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/CIRCRESAHA.107.156877

Shear stress–induced extracellular signal-regulated kinase (ERK)5 activation and the consequent regulation of Kruppel-like factor 2 and endothelial nitric oxide synthase expression represents one of the antiinflammatory and vascular tone regulatory mechanisms maintaining normal endothelial function. Endothelial dysfunction is a major initiator of atherosclerosis, a vascular pathology often associated with diabetes. Small ubiquitin-like modifier (SUMO) covalently attaches to certain residues of specific target transcription factors and could inhibit its activity. We investigated whether H2O2 and AGE (advanced glycation end products), 2 well-known mediators of diabetes, negatively regulated ERK5 transcriptional activity and laminar flow–induced endothelial nitric oxide synthase expression through ERK5 SUMOylation. H2O2 and AGE induced endogenous ERK5 SUMOylation. In addition, ERK5 SUMOylation was increased in the aortas from diabetic mice. ERK5 transcriptional activity, but not kinase activity, was inhibited by expression of Ubc9 (SUMO E2 conjugase) or PIAS1 (E3 ligase), suggesting the involvement of ERK5 SUMOylation on its transcriptional activity. Point-mutation analyses showed that ERK5 is covalently modified by SUMO at 2 conserved sites, Lys6 and Lys22, and that the SUMOylation defective mutant of ERK5, dominant negative form of Ubc9 (DN-Ubc9), and small interfering RNA PIAS1 reversed H2O2 and AGE–mediated reduction of shear stress–mediated ERK5/myocyte enhancer factor 2 transcriptional activity, as well as promoter activity of Kruppel-like factor 2. Finally, PIAS1 knockdown reversed the inhibitory effect of H2O2 in shear stress–induced Kruppel-like factor 2 and endothelial nitric oxide synthase expression. These data clearly defined SUMOylation-dependent ERK5 transcriptional repression independent of kinase activity and suggested this process as among the molecular mechanisms of diabetes-mediated endothelial dysfunction.