| Title | Sp1 transcription factor as a molecular target for nitric oxide-- and cyclic nucleotide--mediated suppression of cGMP-dependent protein kinase-Ialpha expression in vascular smooth muscle cells. | | Author(s) | Sellak H, Yang X, Cao X, Cornwell T, Soff GA, Lincoln T | | Institution | Department of Molecular and Cellular Pathology, University of Alabama in Birmingham, 35294-0019, USA. | | Source | Circ Res 2002 Mar 8; 90(4):405-12. | | MeSH | Animals
Binding Sites
Cattle
Cells, Cultured
Cyclic AMP-Dependent Protein Kinases
Cyclic GMP-Dependent Protein Kinases
Down-Regulation
Enzyme Inhibitors
Gene Expression
Genes, Reporter
Humans
Lipopolysaccharides
Muscle, Smooth, Vascular
Mutagenesis, Site-Directed
Nitric Oxide
Nitric Oxide Donors
Nucleotides, Cyclic
Promoter Regions (Genetics)
Protein Binding
Rats
Receptors, Cytoplasmic and Nuclear
Sp1 Transcription Factor
Transfection
Tumor Necrosis Factor-alpha
| | Abstract | cGMP-dependent protein kinase (PKG) expression is highly variable and decreases in cultured vascular smooth muscle cells (VSMCs), exposure of cells to nitric oxide (NO), or in response to balloon catheter injury in vivo. In this study, the mechanisms of human type I PKG-alpha (PKG-Ialpha) gene expression were examined. Three structurally unrelated NO donors decreased PKG-Ialpha promoter activity after transfection of a promoter/luciferase construct in VSMCs. Promoter deletion analysis demonstrated that (1) a 120-bp promoter containing tandem Sp1 sites was sufficient to drive basal PKG-Ialpha promoter activity, and (2) NO was inhibitory at this site. Cyclic nucleotide analogues also suppressed PKG-Ialpha promoter activity with cAMP being more potent than cGMP. The effects of cyclic nucleotides to suppress PKG-Ialpha promoter activity were attenuated by a specific cAMP-dependent protein kinase (PKA) inhibitor. Single or double mutation of Sp1 binding sites abolished PKG-Ialpha expression. Moreover, Sp1 binding activity on the PKG-Ialpha promoter was detected in A7r5 cells, and this binding was inhibited by NO and cyclic nucleotides. These results indicate that PKG-Ialpha gene expression is driven by an Sp1 transcription mechanism, and that NO and cAMP inhibit Sp1-mediated PKG-Ialpha gene expression through separate mechanisms. | | Language | eng | | Pub Type(s) | Journal Article
| | PubMed ID | 11884369 |
|
