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AT 2 ‐Receptor activation regulates myocardial eNOS expression via the calcineurin‐NF‐AT pathway
Author(s) -
Ritter Oliver,
Schuh Kai,
Breden Marc,
Röthlein Nicola,
Burkard Natalie,
Hein Lutz,
Neyses Ludwig
Publication year - 2003
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.02-0321fje
Subject(s) - enos , stimulation , receptor , angiotensin ii , medicine , endocrinology , calcineurin , chemistry , biology , microbiology and biotechnology , nitric oxide synthase , nitric oxide , transplantation
The role of AT 2 ‐receptors has recently been subject of considerable debate. We investigated the influence of AT 2 ‐stimulation/inhibition on myocardial endothelial NO‐synthase (eNOS, NOS‐III) promoter activity and eNOS protein expression. Stimulation of rat cardiomyocytes with angiotensin II (AngII) increased eNOS protein expression 3.3‐fold. This was blocked by Cyclosporin A (CsA). Inhibition of the AT1‐receptor did not reduce AngII‐mediated eNOS protein expression, whereas AT 2 stimulation increased it 2.4‐fold and AT 2 inhibition suppressed it. The modulatory effects of the AT 2 ‐receptor on eNOS expression was confirmed in mice with a genetic deletion of the AT 2 ‐receptor (AT 2 ‐KO). In gel shift assays two putative NF‐AT sites in a 1.6 kb eNOS promoter fragment showed NF‐AT binding and a supershift by NF‐AT2(‐c1)‐specific antibodies. Stimulation of transfected cells with AngII or specific AT2‐receptor agonists resulted in a significant increase in eNOS promoter activity, which was blocked by CsA, MCIP1, and mutation of an upstream NF‐AT site. Conclusion: 1) AngII‐stimulation of the myocardium, both in vivo and in vitro , is accompanied by increased expression of eNOS. 2) This effect is mediated by the calcineurin pathway and is induced by the AT 2 ‐receptor. 3) These results define a calcineurin/NF‐AT/eNOS pathway as downstream effector of AT 2 ‐receptor activation in the myocardium.