Erschienen in:
01.07.2011 | Original Contribution
Regulation of vascular guanylyl cyclase by endothelial nitric oxide-dependent posttranslational modification
verfasst von:
Marc Oppermann, Tatsiana Suvorava, Till Freudenberger, Vu Thao-Vi Dao, Jens W. Fischer, Martina Weber, Georg Kojda
Erschienen in:
Basic Research in Cardiology
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Ausgabe 4/2011
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Abstract
In isolated cells, soluble guanylyl cyclase (sGC) activity is regulated by exogenous nitric oxide (NO) via downregulation of expression and posttranslational S-nitrosylation. The aim of this study was to investigate whether such regulatory mechanism impact on endothelium-dependent vasodilation in a newly developed mouse strain carrying an endothelial-specific overexpression of eNOS (eNOS++). When compared with transgene negative controls (eNOSn), eNOS++-mice showed a 3.3-fold higher endothelial-specific aortic eNOS expression, increased vascular cGMP and VASP phosphorylation, a L-nitroarginine (L-NA)-inhibitable decrease in systolic blood pressure, but normal levels of peroxynitrite and nitrotyrosine formation, endothelium-dependent aortic vasodilation and vasodilation to NO donors. Western blot analysis for sGC showed similar protein levels of sGC-α1 and sGC-β1 subunits in eNOSn and eNOS++. In striking contrast, the activity of isolated sGC was strongly decreased in lungs of eNOS++. Semiquantitative evaluation of sGC-β1-S-nitrosylation demonstrated that this loss of sGC activity is associated with increased nitrosylation of the enzyme in eNOS++, a difference that disappeared after L-NA-treatment. Our data suggest the existence of a physiologic NO-dependent posttranslational regulation of vascular sGC in mammals involving S-nitrosylation as a key mechanism. Because this mechanism can compensate for reduction in vascular NO bioavailability, it may mask the development of endothelial dysfunction.