Abstract
Atherosclerosis involves cellular immune responses and altered vascular smooth muscle cell (VSMC) function. Nitric oxide (NO)/cGMP is uniquely capable of inhibiting key processes in atherosclerosis. In this study, we determined the effects of NO/cGMP and their molecular mechanisms in the regulation of NF-kappaB-dependent gene expression in VSMCs. We found that cGMP-elevating agents such as the NO donor S-nitroso-N-acetylpenicillamine (SNAP) and C-type natriuretic peptide (CNP), reduced TNF-alpha-induced NF-kappaB-dependent reporter gene expression in rat aortic VSMCs in a cGMP-dependent manner. The effects of SNAP and CNP on NF-kappaB are mediated by cAMP-dependent protein kinase (PKA) but not cGMP-dependent protein kinase (PKG) based on the findings that the selective PKA inhibitor, PKI, abolished the effects of SNAP and CNP on NF-kappaB, whereas the PKG inhibitor Rp-8-Br-PET-cGMP had no effect. Inhibition of cGMP-inhibited cAMP-hydrolyzing phosphodiesterase 3 (PDE3) blocked SNAP- and CNP-elicited effects on NF-kappaB-dependent transcription. Furthermore, cGMP analogues such as 8-pCPT-cGMP, which selectively activates PKG but does not inhibit PDE3, had no effect on NF-kappaB-mediated transcription. Activation of PKA by SNAP or cAMP-elevating agents not only inhibited TNF-alpha-induced NF-kappaB-dependent reporter gene expression but also reduced endogenous NF-kappaB-dependent adhesion molecule and chemokine expression. These results suggest that SNAP and CNP exert inhibitory effects on NF-kappaB-dependent transcription by activation of PKA via cGMP-dependent inhibition of PDE3 activity. Therefore, PDE3 is a novel mediator of inflammation in VSMCs.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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3',5'-Cyclic-AMP Phosphodiesterases / metabolism*
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3',5'-Cyclic-AMP Phosphodiesterases / physiology
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Animals
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Blotting, Western
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Cells, Cultured
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Chemokine CCL2 / genetics
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Cyclic AMP-Dependent Protein Kinases / metabolism
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Cyclic GMP / analogs & derivatives*
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Cyclic GMP / metabolism*
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Cyclic GMP / pharmacology
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Cyclic GMP-Dependent Protein Kinases / metabolism
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Cyclic Nucleotide Phosphodiesterases, Type 3
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Enzyme Inhibitors / pharmacology
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Gene Expression Regulation / drug effects
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Guanylate Cyclase / antagonists & inhibitors
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Inflammation Mediators / metabolism
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Luciferases / genetics
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Luciferases / metabolism
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Muscle, Smooth, Vascular / cytology
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Muscle, Smooth, Vascular / drug effects
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Muscle, Smooth, Vascular / metabolism*
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NF-kappa B / genetics
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NF-kappa B / metabolism
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Natriuretic Peptide, C-Type / pharmacology
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Nitric Oxide / metabolism*
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Nitric Oxide Donors / pharmacology
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Oxadiazoles / pharmacology
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Quinoxalines / pharmacology
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RNA, Messenger / drug effects
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Rats
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S-Nitroso-N-Acetylpenicillamine / pharmacology
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Thionucleotides / pharmacology
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Transcription, Genetic / drug effects
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Tumor Necrosis Factor-alpha / pharmacology
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Vascular Cell Adhesion Molecule-1 / genetics
Substances
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1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one
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Chemokine CCL2
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Enzyme Inhibitors
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Inflammation Mediators
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NF-kappa B
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Nitric Oxide Donors
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Oxadiazoles
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Quinoxalines
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RNA, Messenger
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Thionucleotides
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Tumor Necrosis Factor-alpha
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Vascular Cell Adhesion Molecule-1
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Natriuretic Peptide, C-Type
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8-bromoguanosino-3',5'-cyclic monophosphorothioate
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Nitric Oxide
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8-((4-chlorophenyl)thio)cyclic-3',5'-GMP
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S-Nitroso-N-Acetylpenicillamine
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Luciferases
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Cyclic AMP-Dependent Protein Kinases
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Cyclic GMP-Dependent Protein Kinases
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3',5'-Cyclic-AMP Phosphodiesterases
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Cyclic Nucleotide Phosphodiesterases, Type 3
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Guanylate Cyclase
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Cyclic GMP