1. Angiotensin-(1-5) is a Potent Endogenous Angiotensin AT 2 -Receptor Agonist.
- Author
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Souza-Silva IM, Peluso AA, Elsaafien K, Nazarova AL, Assersen KB, Rodrigues-Ribeiro L, Mohammed M, Rodrigues AF, Nawrocki A, Jakobsen LA, Jensen P, de Kloet AD, Krause EG, Borgo MD, Maslov I, Widdop R, Santos RA, Bader M, Larsen M, Verano-Braga T, Katritch V, Sumners C, and Steckelings UM
- Abstract
Background: The renin-angiotensin system involves many more enzymes, receptors and biologically active peptides than originally thought. With this study, we investigated whether angiotensin-(1-5) [Ang-(1-5)], a 5-amino acid fragment of angiotensin II, has biological activity, and through which receptor it elicits effects., Methods: The effect of Ang-(1-5) (1µM) on nitric oxide release was measured by DAF-FM staining in human aortic endothelial cells (HAEC), or Chinese Hamster Ovary (CHO) cells stably transfected with the angiotensin AT
2 -receptor (AT2 R) or the receptor Mas. A potential vasodilatory effect of Ang-(1-5) was tested in mouse mesenteric and human renal arteries by wire myography; the effect on blood pressure was evaluated in normotensive C57BL/6 mice by Millar catheter. These experiments were performed in the presence or absence of a range of antagonists or inhibitors or in AT2 R-knockout mice. Binding of Ang-(1-5) to the AT2 R was confirmed and the preferred conformations determined by in silico docking simulations. The signaling network of Ang-(1-5) was mapped by quantitative phosphoproteomics., Results: Key findings included: (1) Ang-(1-5) induced activation of eNOS by changes in phosphorylation atSer1177 eNOS andTyr657 eNOS and thereby (2) increased NO release from HAEC and AT2 R-transfected CHO cells, but not from Mas-transfected or non-transfected CHO cells. (3) Ang-(1-5) induced relaxation of preconstricted mouse mesenteric and human renal arteries and (4) lowered blood pressure in normotensive mice - effects which were respectively absent in arteries from AT2 R-KO or in PD123319-treated mice and which were more potent than effects of the established AT2 R-agonist C21. (5) According to in silico modelling, Ang-(1-5) binds to the AT2 R in two preferred conformations, one differing substantially from where the first five amino acids within angiotensin II bind to the AT2 R. (6) Ang-(1-5) modifies signaling pathways in a protective RAS-typical way and with relevance for endothelial cell physiology and disease., Conclusions: Ang-(1-5) is a potent, endogenous AT2 R-agonist.- Published
- 2024
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