Angiotensin II-induced upregulation of MAP kinase phosphatase-3 mRNA levels mediates endothelial cell apoptosis.
Angiotensin II (Ang II) is central to the pathobiology of atherosclerosis. In endothelial cells (EC), Ang II induces apoptosis. The MAP kinase ERK1/2 plays a key role in regulating cell survival. We therefore investigated the effect of Ang II on ERK1/2. Incubation of EC with Ang II led to the dephosphorylation of ERK1/2 (43% of control). To characterize the phosphatase involved, we investigated the effect of Ang II on MAP kinase phosphatase expression. Ang II induced MAP kinase phosphatase-3 (MKP-3) mRNA levels to about 2-fold, whereas MKP-1 expression was not affected. Transfection with a dominant negative MKP-3 construct (dnMKP-3mt) prevented the Ang II-induced ERK1/2 dephosphorylation and apoptosis in EC (p < 0.001). ERK1/2 inactivation has been shown to result in the dephosphorylation and proteasomal degradation of the antiapoptotic protein Bcl-2. Ang II induced the degradation of Bcl-2 wild type, whereas the dephosphorylation-resistant Bcl-2 construct mimicking phosphorylation by ERK1/2 was resistant to Ang II stimulation. These results indicate that Ang II-induced apoptosis signaling in human EC is mediated via MKP-3-dependent dephosphorylation of ERK1/2, which in turn leads to the degradation of Bcl-2.
Rössig
Lothar
L
Department of Medicine IV, University of Frankfurt, Germany.
Hermann
Corinna
C
Haendeler
Judith
J
Assmus
Birgit
B
Zeiher
Andreas M
AM
Dimmeler
Stefanie
S
D000804:Angiotensin II / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D015153:Blotting, Western; D002478:Cells, Cultured; D054642:Dual Specificity Phosphatase 6; D004727:Endothelium / Q000166:cytology / Q000187:drug effects*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D020935:MAP Kinase Signaling System / Q000187:drug effects; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017027:Protein Tyrosine Phosphatases / Q000235:genetics* / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014162:Transfection; D015854:Up-Regulation / Q000187:drug effects*
D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D000804:Angiotensin II; D020928:Mitogen-Activated Protein Kinases; C517035:DUSP6 protein, human; D054642:Dual Specificity Phosphatase 6; D017027:Protein Tyrosine Phosphatases