Nitric oxide down-regulates MKP-3 mRNA levels: involvement in endothelial cell protection from apoptosis.
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.
Rössig
L
L
Molecular Cardiology, Department of Internal Medicine IV, University of Frankfurt, Germany.
Haendeler
J
J
Hermann
C
C
Malchow
P
P
Urbich
C
C
Zeiher
A M
AM
Dimmeler
S
S
D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D019556:COS Cells; D002478:Cells, Cultured; D003574:Cytochrome c Group / Q000378:metabolism; D015536:Down-Regulation; D054642:Dual Specificity Phosphatase 6; D004730:Endothelium, Vascular / Q000378:metabolism; D004789:Enzyme Activation; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D008954:Models, Biological; D009569:Nitric Oxide / Q000378:metabolism / Q000502:physiology*; D010744:Phosphoric Monoester Hydrolases / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D014176:Protein Biosynthesis; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D013997:Time Factors; D014158:Transcription, Genetic; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014471:Umbilical Veins / Q000378:metabolism
D003574:Cytochrome c Group; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D010744:Phosphoric Monoester Hydrolases; C517035:DUSP6 protein, human; D054642:Dual Specificity Phosphatase 6; D017027:Protein Tyrosine Phosphatases