Nitric oxide down-regulates MKP-3 mRNA levels: involvement in endothelial cell protection from apoptosis

• Published in: The Journal of biological chemistry 2000-08, Vol.275 (33), p.25502-25507
• Main Authors: Rössig, L, Haendeler, J, Hermann, C, Malchow, P, Urbich, C, Zeiher, A M, Dimmeler, S
• Format: Article
• Language: English
• Subjects: Animals; Apoptosis; Blotting, Western; Cells, Cultured; COS Cells; Cytochrome c Group - metabolism; Down-Regulation; Dual Specificity Phosphatase 6; Endothelium, Vascular - metabolism; Enzyme Activation; Humans; Mitochondria - metabolism; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases - metabolism; Models, Biological; Nitric Oxide - metabolism; Nitric Oxide - physiology; Phosphoric Monoester Hydrolases - metabolism; Phosphorylation; Plasmids - metabolism; Protein Biosynthesis; Protein Tyrosine Phosphatases - metabolism; Proto-Oncogene Proteins c-bcl-2 - metabolism; RNA, Messenger - metabolism; Time Factors; Transcription, Genetic; Transfection; Tumor Necrosis Factor-alpha - metabolism; Umbilical Veins - metabolism
• ISSN: 0021-9258
• DOI: 10.1074/jbc.M002283200

MAP kinase-dependent phosphorylation processes have been shown to interfere with the degradation of the antiapoptotic protein Bcl-2. The cytosolic MAP kinase phosphatase MAP kinase phosphatase-3 (MKP-3) induces apoptosis of endothelial cells in response to tumor necrosis factor alpha (TNFalpha) via dephosphorylation of the MAP kinase ERK1/2, leading to Bcl-2 proteolysis. Here we report that the endothelial cell survival factor nitric oxide (NO) down-regulated MKP-3 by destabilization of MKP-3 mRNA. This effect of NO was paralleled by a decrease in MKP-3 protein levels. Moreover, ERK1/2 was found to be protected against TNFalpha-induced dephosphorylation by coincubation of endothelial cells with the NO donor. Subsequently, both the decrease in Bcl-2 protein levels and the mitochondrial release of cytochrome c in response to TNFalpha were largely prevented by exogenous NO. In cells overexpressing MKP-3, no differences in phosphatase activity in the presence or absence of NO were found, excluding potential posttranslational modifications of MKP-3 protein by NO. These data demonstrate that upstream of the S-nitrosylation of caspase-3, NO exerts additional antiapoptotic effects in endothelial cells, which rely on the down-regulation of MKP-3 mRNA.