MasR and pGCA receptor activation protects primary vascular smooth muscle cells and endothelial cells against oxidative stress via inhibition of intracellular calcium

Abstract

Cardiovascular diseases (CVDs) are associated with vascular smooth muscle cell (VSMC) and endothelial cell (EC) damage. Angiotensin1-7 (Ang1-7) and B-type natriuretic peptide (BNP) are responsible for vasodilation and regulation of blood flow. These protective effects of BNP are primarily mediated by the activation of sGCs/cGMP/cGKI pathway. Conversely, Ang1-7 inhibits Angiotensin II-induced contraction and oxidative stress via Mas receptor activation. Thus, the aim of the study was to determine the effect of co-activation of MasR and particulate guanylate cyclase receptor (pGCA) pathways by synthesized novel peptide (NP) in oxidative stress-induced VSMCs and ECs. MTT and Griess reagent assay kits were used for the standardization of the oxidative stress (H 2 O 2 ) induced model in VSMCs. The expression of targeted receptors in VSMC was done by RT-PCR and Western blot analysis. Protective effect of NP in VSMC and EC was determined by immunocytochemistry, FACS analysis, and Western blot analysis. Underlying mechanisms of EC-dependent VSMC relaxation were done by determining downstream mRNA gene expression and intracellular calcium imaging of cells. Synthesized NP significantly improved oxidative stress-induced injury in VSMCs. Remarkably, the actions of NP were superior to that of the Ang1-7 and BNP alone. Further, a mechanistic study in VSMC and EC suggested the involvement of upstream mediators of calcium inhibition for the therapeutic effect. NP is reported to possess vascular protective activities and is also involved in the improvement of endothelial damage. Moreover, it is highly effective than that of individual peptides BNP and Ang1-7 and therefore it may represent a promising strategy for CVDs.

Identification and characterization of alamandine-(1-5), a new component of the Renin-Angiotensin System with unique properties

“…Considering that there were no important changes in the contractile effect in endothelium denuded vessels or by pre-treatment with L-Name, a direct effect on vascular smooth muscle would be possible. Indeed presence of Mas, MrgD and AT2R, receptors probably involved in this alamandine-(1-5) effect (see below), was reported in VSM cells [22][23][24][25][26] . It should be pointed out that, in view of the absence of losartan effect on the alamandine-(1-5) effect in aortic rings, AT1R appears not to play a role in the alamandine- (1)(2)(3)(4)(5) actions in mice aortic rings.…”

The RAAS Goodfellas in Cardiovascular System

“…Natriuretic peptides, particularly the atrial natriuretic peptide (ANP), are also known to have important vasodilatory and anti-hypertensive properties [98]. Recent evidence reported a strong protective effect of a novel dual-acting peptide (DAP) against vascular damage: this peptide, combining the Ang 1-7 sequence with part of the brain natriuretic peptide (BNP) and of ANP, enhances the cardiovascular protection provided by the single elements, acting via the co-activation of Mas and particulate guanylyl cyclase-A receptor, reducing H 2 O 2 -induced ROS generation, preventing vascular hypertrophy, attenuating intracellular calcium levels (and therefore, contraction) in VSMC and activating PI3K/AKT/eNOS pathway in ECs [99,100].…”